DRY SPRINKLER ASSEMBLIES

Abstract

A dry sprinkler for a fire protection system having a configuration with one or more coupling arrangements for connection to a fluid supply piping of the system. The dry sprinkler structure further includes an inner surface and inner assembly to provide a preferred discharge performance. The dry sprinkler provides for a flow rate from the outlet of the sprinkler in accordance with the start pressure at the inlet of the sprinkler and the rated discharge coefficient, K factor, ranging between 16.8 GPM/PSI½ and 33.6 GPM/PSI½.

Claims

1. A dry sprinkler comprising: an outer structural assembly having a proximal inlet, a distal outlet, and an internal passageway extending between the inlet and the outlet defining a longitudinal axis of the sprinkler and a nominal K-factor as determined by a flow rate of fluid in gallons per minute from the distal outlet divided by the square root of a pressure of the fluid fed into the proximal inlet, the outer structural assembly including: an outlet frame including an internal bore defining a distal portion of the passageway including the outlet, the outlet frame including a deflector axially spaced at a fixed distance from the outlet; an inlet fitting including a proximal head portion and a distal body portion, the head portion having an external thread defining a nominal external thread diameter, the body portion including an external groove defining a nominal groove diameter being nominally greater than the nominal external thread diameter, the external thread and groove providing the sprinkler with alternate threaded-type and grooved-type coupling arrangements for connection to a fluid supply pipe, the inlet fitting haying an inner surface defining a sealing surface of the dry sprinkler, the inner surface of the inlet fitting defining a proximal portion of the passageway having a first section and a second section distal of the first section with an internal diameter of the second section being greater than an internal diameter of the first section; and a casing tube disposed between the inlet fitting and an outlet frame, the casing tube having an internal surface defining a section of the passageway between the outlet frame and the inlet fitting; a thermal trigger assembly engaged with the outlet frame in an unactuated state of the sprinkler; and a seal assembly disposed along the passageway, the seal assembly being supported by the thermal trigger assembly and in contact with the sealing surface in an unactuated state of the sprinkler, the sealing assembly being located in the second section in an actuated state of the sprinkler such that the sealing assembly is spaced from the sealing surface so as to permit fluid to flow from the outlet at about the flow rate defined by the nominal K-factor, the nominal K-factor ranging from 16.8 GPM/PSI.sup.1/2 to 33.6 GPM/PSI.sup.1/2.

2. The dry sprinkler of claim 1, wherein the sealing surface is located such drat at leas portion of the external thread extends distally of the sealing surface.

3. The dry sprinkler of claim 1, wherein at least a portion of the external thread of the inlet fitting extends proximally of the sealing surface.

4. The dry sprinkler of claim 1, wherein the seal assembly includes a mounting member and a spring seal, the spring seal includes a central opening, the mounting member having a diverter portion extending through the central opening.

5. The dry sprinkler of claim 4, wherein the diverter portion is substantially conical and a diverter height of about 0.5 inches.

6. A dry sprinkler comprising: an outer structural assembly having a proximal inlet, a distal outlet, and an internal passageway extending between the inlet and the outlet defining a longitudinal axis of the sprinkler and a nominal K-factor as determined by a flow rate of fluid in gallons per minute from the distal outlet divided by the square root of a pressure of the fluid fed into the proximal inlet, the nominal K-factor ranging from 16.8 GPM/PSI.sup.1/2 to 33.6 GPM/PSI.sup.1/2, the outer structural assembly including: an outlet frame including an internal bore defining a distal portion of the passageway including the outlet, the outlet frame including a deflector axially spaced at a fixed distance from the outlet; art inlet fitting including a proximal head portion and a distal body portion, the head portion having an external thread for a threaded-type coupling, the body portion including an external groove for a grooved-type coupling, the inlet fitting having an inner surface defining a proximal portion of the internal passageway and a sealing surface; and a casing tube disposed between the inlet fitting and an outlet frame, the casing tube having an internal surface defining a section of the passageway between the outlet frame and the inlet fitting; a thermal trigger assembly for thermally triggering the sprinkler from an unactuated state to an actuated state, the trigger being engaged with the outlet frame in an unactuated state of the sprinkler; and an internal structural assembly disposed within the passageway supported by the thermal trigger, the internal structural assembly translating axially from a first position to a second position upon the sprinkler going front the unactuated state to the actuated state, the internal structural assembly including: a fluid tube having a proximal end and a distal end; and a seal assembly supported by the fluid tube and in contact with the sealing surface in the first position, the sealing assembly being spaced from the sealing surface in the second position so as to permit fluid to flow from the outlet at about the flow rate defined by the nominal K-factor, the seal assembly includes a mounting member and a spring seal disposed on the mounting member for contacting the sealing surface in the first position, the mounting member being affixed to the proximal end of the fluid tube such that the sealing assembly member and the fluid tube are maintained in a fixed distance relationship to one another in translation of the internal structural assembly from the first and second positions; and a guide tube disposed in the outlet frame and engaged with the fluid tube.

7. The dry sprinkler of claim 6, wherein the external thread of the inlet fitting extends proximally of the sealing surface.

8. The dry sprinkler of claim 6, wherein the spring seal includes a central opening, the mounting member having a diverter portion extending through the central opening.

9. The dry sprinkler of claim 8, wherein the diverter portion is substantially conical and a diverter height of about 0.5 inches.

10. A dry sprinkler comprising: an outer structural assembly having a proximal inlet, a distal outlet, and an internal passageway extending between the inlet and the outlet defining a longitudinal axis of the sprinkler and a nominal K-factor as determined by a flow rate of fluid in gallons per minute from the distal outlet divided by the square root of a pressure of the fluid fed into the proximal inlet, the nominal K-factor ranging from 16.8 GPM/PSI.sup.1/2 to 33.6 GPM/PSI.sup.1/2, the outer structural assembly including: an outlet frame including an internal bore defining the outlet, the outlet frame including a deflector axially spaced at a fixed distance from the outlet; and an inlet fitting including a proximal head portion and a distal body portion, the inlet fitting having a coupling arrangement for at, least one of a thread-type coupling and groove-type coupling arrangement for connection to a fluid supply pipe, the inlet fitting including a sealing surface of the dry sprinkler disposed axially along the inner surface; a casing tube disposed between the inlet fitting and an outlet frame, the casing tube having an internal surface defining a section of the passageway between the outlet frame and the inlet fitting; a thermal trigger assembly for thermally triggering the sprinkler from an unactuated state to an actuated state, the trigger being engaged with the outlet frame in an unactuated state of the sprinkler; and an internal structural assembly disposed within the passageway supported by the thermal trigger, the internal structural assembly translating axially from a first position to a second position upon the sprinkler going from the unactuated state to the actuated state, the internal structural assembly including: a fluid tube having a proximal end and a distal end; and a seal assembly supported by the fluid tube and in contact with the sealing surface in the first position, the sealing assembly being spaced from the sealing surface in the second position so as to permit fluid to flow from the outlet at about the flow rate defined by the nominal K-factor, the seal assembly being engaged with a proximal end of the fluid tube such that the seal assembly translates with respect to the fluid tube upon translation of the internal structural assembly from the first position to the second position, the fluid tube translating a first distance with respect to the sealing surface and the seal assembly translating a second distance with respect to the sealing surface a second distance greater than the first distance; and a guide tube disposed in the outlet frame and engaged with the fluid tube.

11. The dry sprinkler of claim 10, wherein the seal assembly comprises a yoke assembly having a mounting member and a seal spring engaged with the mounting member, the mounting member including a plurality of levers each pivotally engaged with the mounting member, wherein the levers pivot from a first orientation to a second orientation so as to translate the mounting member relative to the fluid tube.

12. The dry sprinkler of claim 11, wherein the spring seal includes a central opening, the mounting member having a diverter portion extending through the central opening.

13. The dry sprinkler of claim 12, wherein the diverter portion is substantially conical and a diverter height of about 0.5 inches.

14. The dry sprinkler of claim 10, wherein the external thread of the inlet fitting extends distally of the sealing surface.

15. A dry sprinkler comprising: an outer structural assembly having a proximal inlet, a distal outlet, and an internal passageway extending between the inlet and the outlet defining a longitudinal axis of the sprinkler, the outer structural assembly including: an outlet frame including an internal bore defining a distal portion of the passageway including the outlet, the outlet frame including a deflector axially spaced at a fixed distance from the outlet; an inlet fitting including a proximal head portion and a distal body portion, the head portion having an external thread and the body portion including an external groove, the external thread and groove providing the sprinkler with alternate coupling arrangements for connection to a fluid supply pipe, the inlet fitting having an inner surface defining a sealing surface of the dry sprinkler disposed along the head portion such that the external thread extends distally of the sealing surface; and a casing tube disposed between the inlet fitting and an outlet frame, the casing tube having an internal surface defining a section of the passageway between the outlet frame and the inlet frame; a thermal trigger assembly for thermally triggering the sprinkler from an unactuated state to an actuated state, the thermal trigger assembly engaged with the outlet frame in an unactuated state of the sprinkler; and a seal assembly disposed along the passageway, the seal assembly being supported by the trigger in contact with the sealing surface in an unactuated state of the sprinkler, the sealing assembly in an actuated state of the sprinkler being spaced from the sealing surface, wherein the sealing assembly remains centered along the longitudinal axis in each of the unactuated and actuated states.

16. The dry sprinkler of claim 15, wherein the sealing surface is located such that at least a portion of the external thread extends distally of the sealing surface.

17. The dry sprinkler of claim 15, wherein at least a portion of the external thread of the inlet fitting extends proximally of the sealing surface.

18. A dry sprinkler comprising: an outer structural assembly having a proximal inlet, a distal outlet, and an internal passageway extending between the inlet and the outlet defining a longitudinal axis of the sprinkler, the outer structural assembly including: an outlet frame including an internal bore defining the outlet, the outlet frame including a deflector axially spaced at a fixed distance from the outlet; an inlet fitting including a proximal head portion and a distal body portion, the head portion including an external thread for a threaded-type coupling connection to a fluid supply pipe, the inlet fitting having an inner surface defining a proximal portion of the internal passageway coaxially and symmetrically disposed about the longitudinal axis, the inlet fitting including a sealing surface of the dry sprinkler disposed axially along the inner surface such that the external thread extends proximally of the sealing surface; and a casing tube disposed between the inlet fitting and an outlet frame; a thermal trigger assembly for thermally triggering the sprinkler from an unactuated state to an actuated state, the thermal trigger assembly engaged with the outlet frame in an unactuated state of the sprinkler; and a seal assembly disposed along the passageway coaxially aligned along the longitudinal axis, wherein in the unactuated state of the sprinkler, the seal assembly is supported by the thermal trigger assembly so as to be in contact with the sealing surface, and in an actuated state of the sprinkler the sealing assembly being spaced from the sealing surface, the proximal portion of the passageway being coaxially aligned and symmetrically disposed about the sealing assembly in each of the unactuated and actuated states.

19. A dry sprinkler comprising: an outer structural assembly having a proximal inlet, a distal outlet, and an internal passageway extending between the inlet and the outlet defining a longitudinal axis of the sprinkler, the outer structural assembly including: an outlet frame including an internal bore defining the outlet, the outlet frame including a deflector axially spaced at a fixed distance from the outlet; an inlet fitting including a proximal head portion and a distal body portion, the inlet fitting having a coupling arrangement for at least one of a thread-type coupling and groove-type coupling arrangement for connection to a fluid supply pipe, the inlet fitting having an inner surface defining a proximal portion of the internal passageway and a sealing surface; and a casing tube disposed between the inlet fitting and an outlet frame: a thermal trigger assembly for thermally triggering the sprinkler from an unactuated state to an actuated state, the trigger being engaged with the outlet frame in an unactuated state of the sprinkler; and an internal structural assembly disposed within the passageway supported by the thermal trigger, the internal structural assembly including: a fluid tube having a proximal end and a distal end, the fluid tube translating axially from a first position to a second position upon the sprinkler going from the unactuated state to the actuated state; and a seal assembly supported by the fluid tube, the seal assembly being contacting the sealing surface in the first position, the sealing assembly being spaced from the sealing surface in the second position so as to permit fluid to flow from the outlet at about the flow rate defined by the nominal K-factor, the seal assembly translating with respect to the fluid tube upon translation of the internal structural assembly from the first position to the second position.

20. The dry sprinkler of claim 19, wherein inlet fitting includes an external thread, the sealing surface is located such that at least a portion of the external thread extends distally of the sealing surface.

21. The dry sprinkler of claim 19, wherein inlet fitting includes an external thread, the sealing surface is located such that at least a portion of the external thread extends proximally of the sealing surface.

22. The dry sprinkler of claim 19, wherein the seal assembly comprises a yoke assembly having a mounting member and a seal spring engaged with the mounting member, the mounting member including a plurality of levers each pivotally engaged with the mounting member, wherein the levers pivot from a first orientation to a second orientation so as to translate the mounting member relative to the fluid tube.

23. The dry sprinkler of claim 22, wherein the spring seal includes a central opening, the mounting member having a diverter portion extending through the central opening.

24. The dry sprinkler of claim 23, wherein the diverter portion is substantially conical and a diverter height of about 0.5 inches.

25. The dry sprinkler of any one of the above claims, wherein the inlet fitting defines an entrance surface proximal of the sealing surface, the entrance surface having a radiused profile.

26. The dry sprinkler of any one of the above claims, wherein the inlet fitting defines an entrance surface proximal of the sealing surface, the entrance surface having a tapered profile.

27. The dry sprinkler of any one of the above claims, wherein the nominal K-factor is nominally one of (i) 16.8 (16.0-17.6) GPM/(PSI).sup.1/2; (ii) 19.6 (18.6-20.6) GPM/(PSI).sup.1/2; (iii) 22.4 (21.3-23.5) GPM/(PSI).sup.1/2; (iv) 25.2 (23.9-26.5) GPM/(PSI).sup.1/2; (v) 28.0 (26.6-29.4) GPM/(PSI).sup.1/2; and 33.6 (31.9-35.3) GPM/(PSI).sup.1/2.

28. The dry sprinkler of any one of the above claims, wherein the nominal K-factor is 16.8 GPM/(PSI).sup.1/2, the external groove defines a nominal 2 inches for coupling to a correspondingly sized pipe or pipe fitting.

29. The dry sprinkler of any one of the above claims, wherein external threads comprise American National Standard Taper Pipe Thread (NPT) defining a nominal 1.25 inch.

30. The dry sprinkler of any one of the above claims, wherein the casing tube defines a nominal pipe diameter of 1½ inch and an axial length between about two to about fifty inches.

31. The dry sprinkler of any one of the above claims, wherein the inner surface of the inlet fitting expands the passageway from the sealing surface and distally converges toward the casing tube.

32. The dry sprinkler of any one of the above claims, wherein the external groove defines a nominal 2 inches and the sealing surface defines an internal opening diameter of about 1¼ inch.

33. The dry sprinkler of any one of the above claims, wherein the external pipe thread defines a 1¼ inch diameter and the sealing surface defines an internal opening with a diameter of about one inch (1 in.).

34. The system of any one of claims 6, 10 and 19, wherein the internal assembly comprises a fluid tube, a guide tube and trigger seat supported by the thermal trigger in the unactuated state of the sprinkler, the fluid tube including a plurality of apertures and a plurality of projections.

35. The system of any one of claims 1, 15, and 18, wherein the dry sprinkler further comprises an internal assembly comprises a fluid tube, a guide tube and trigger seat supported by the thermal trigger in the unactuated state of the sprinkler, the fluid tube including a plurality of apertures and a plurality of projections.

36. The dry sprinkler of any one of the above claims, wherein the outlet defines a diameter of about 0.95 inch with the sprinkler having the K-factor value to about 17 GPM/(PSI).sup.1/2.

37. The thy sprinkler of any one of the above claims, wherein the outlet is about 1.125 inches and wherein the seal assembly defines an axial displacement of about 0.75 inch with the sprinkler having the K-factor value to about 19.6 CPM/(PSI).sup.1/2,

38. The dry sprinkler in any one of the above claims, wherein the thermal trigger assembly element is one of a solder thermal trigger assembly and frangible bulb.

39. The dry sprinkler in any one of the above claims, wherein the trigger element is thermally rated for any one of 135, 155, 165, 175, 200, 214 or 286 degrees Fahrenheit.

40. The dry sprinkler in any one of the above claims, wherein the trigger element has an RT1 of 50 (meters-seconds).sup.1/2 or less.

41. The dry sprinkler in any one of the above claims, wherein the trigger element has an RTI of 80 (meters-seconds).sup.1/2 or more.

Description

BRIEF DESCRIPTIONS OF THE DRAWINGS

[0022] The accompanying drawings, which are incorporated herein and constitute part of this specification, illustrate exemplary embodiments of the invention, and, together with the general description given above and the detailed description given below, serve to explain the features of the invention.

[0023] FIG. 1A illustrates a preferred threaded connection of a preferred thy sprinkler of using a threaded connection with a fluid supply pipe;

[0024] FIG. 1B illustrates a preferred grooved-type coupling connection of the preferred dry sprinkler of FIG. 1A casing a groove-type coupling;

[0025] FIG. 1C is a cross-sectional view of a preferred embodiment of a dry sprinkler in an unactuated state;

[0026] FIG. ID is a cross-sectional view of the preferred sprinkler of FIG. 1 in an actuated state;

[0027] FIG. 2 is one preferred embodiment of an inlet fitting for use in a dry sprinkler;

[0028] FIG. 3 is another preferred embodiment of an inlet kitting for use in the dry sprinkler of FIGS. 1C and ID;

[0029] FIG. 4 is a detailed view of another cross-section of a portion of the dry sprinkler of FIGS. 1C and ID;

[0030] FIG. 4A is an alternate a detailed cross-sectional view of the dry sprinkler of FIGS. 1C and ID having a thermal trigger in the form of a frangible bulb.

[0031] FIG. 5 is a detailed cross-sectional view of the seal assembly in the dry sprinkler of FIGS. IC and ID;

[0032] FIG. 6 is a detailed cross-sectional view of another preferred seal assembly for use in the dry sprinkler of FIGS. 1C and ID;

[0033] FIG. 7 is a cross-sectional perspective view of the dry sprinkler of FIGS. 1C and ID;

[0034] FIG. 8 is a cross-sectional view of another preferred embodiment of a dry sprinkler in an unactuated state using the inlet fitting of FIG. 2;

[0035] FIG. 8A is a cross-sectional view of the dry sprinkler of FIG. 8 in an actuated state;

[0036] FIG. 9 is a perspective view of a yoke sub-assembly in a first configuration for use in the dry sprinkler of FIGS. 8 and 8A;

[0037] FIG. 9A is a perspective view of the yoke sub-assembly in FIG. 9 in a second configuration for use in the dry sprinkler of FIGS. 8 and 8A;

[0038] FIG. 9B is a detailed cross-sectional view of the yoke sub-assembly of FIG. 9.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039] FIGS. 1A and IB illustrate a preferred embodiment of a dry sprinkler 10 installed and coupled to a pipe fitting of a piping network, which is supplied with a fire fighting fluid, e.g., fluid from a pressurized fluid supply source. The preferred embodiments described herein include dry sprinklers that are suitable for use, for example, with a dry pipe system (e.g. at least a portion of the system is exposed to freezing temperatures in an unheated portion of a building) or a wet pipe system (e.g. the entire system is not exposed to freezing temperatures in an unheated portion of a building) or both. Fluid supply piping systems may be installed in accordance with the NFPA 13. As seen in FIGS. 1C and ID, the dry sprinkler 10 includes an miter structure assembly 18, an inner structural assembly 50, and a thermal trigger 80. The outer structure assembly 18 defines an internal passageway 18a that extends along a central longitudinal axis A-A between a proximal inlet end 12 and a distal outlet end 14. The outer structure assembly 18 preferably includes an inlet fitting 20 at the proximal end, an outlet frame 30 at the distal end with a casing tube 22 preferably in between coupling the inlet fitting 20 to the outlet frame 30.

[0040] The inlet fitting 20 includes an outer surface 20b and an inner surface 20c which in the sprinkler assembly, preferably defines a portion of the passageway 18a. The inlet fitting outer surface 20b preferably includes fitting threads 204, a clamp groove 266, and a tool engagement portion 268 at the preferably distal end of the fitting 20. The preferred inlet fitting 20 defines a proximal head portion 220 that includes the external fitting threads 204 and a larger distal body portion 260 that includes the external clamp groove 266. The body portion further preferably defines a step transition between the fitting threads 204 and the groove 266 that is preferably circularly circumscribed about the axis A-A so as to define a transition portion 206 of the inlet fitting 20, as seen for example, in FIGS. 2 and 3. The threads 204 and groove 266 provide the dry sprinkler with a single fitting having preferred alternative means for coupling the dry sprinkler 10 to the fluid supply lines of a sprinkler system. More specifically, the threads 204 permit the dry sprinkler to be coupled to a fluid supply line by a threaded connection, as seen for example, in FIG. 1A. The clamp groove 266 permits the dry sprinkler 10 to be connected to the fluid supply line by a groove-type coupling connection, as seen for example, in FIG. 1B. The distal end portion of the fitting 20 preferably includes a tool engagement portion 268 having an exterior shape, e.g., a hexagon, that is suitable for applying, for example, a torque to the inlet fitting 20 when the dry sprinkler 10 is threadably coupled to the piping network via the fitting threads 204. The preferred shape of the inlet fitting 20 with the proximal head portion and larger body portion with the narrowing taper allows for the distal end of the inlet fitting to be coupled to a narrower casing tube 22. Minimizing dimensions of the sprinkler components, such as for example the diameter of the casing tube, can reduce the overall weight and volume of the sprinkler making the sprinkler manageable for handling and shipping. Accordingly, the preferred dry sprinkler can maintain a preferred sprinkler weight (lbs.) to length (inches) ratio. For one preferred embodiment of the sprinkler 10 having a preferred nominal K-factor of 16.8 GPM/(PSI).sup.1/2, a total assembled sprinkler length of about 37 inches, and a total assembled sprinkler weight of about ten pounds (10 lbs.), the preferred sprinkler defines a preferred weight to length ratio of about 0.27 lbs./in. and a preferred weight to K-factor ratio of about 0.6 lbs per GPM/(PSI).sup.1/2. Alternatively, the outer surface 20b may define alternative profiles over its axial length. For example, the outer surface may define a broadening profile in the proximal to distal direction over the length of the inlet fitting 20.

[0041] The clamp groove 266 is preferably disposed along the distal body portion 260 downstream of the head portion 220 and more preferably distal of the inlet fitting threads 204. The preferred transition portion 206 provides a surface 202 that faces, contacts, engages and/or preferably abuts the end of a complimentary grooved pipe or pipe fitting of a fluid supply branch line. More preferably, the surface 202 of the transition portion 206 generally provides a surface that extends substantially perpendicularly to the longitudinal axis A-A of the sprinkler and in one aspect defines a stop surface. Accordingly, the groove 266 is preferably located distally of the surface 202, between the surface 202 and the distal end portion, so that the dry sprinkler 10 and the mating pipe fitting can be preferably coupled together by commercially available groove-type pipe couplings. Accordingly the transition between the surface 202 and the groove 26 may define a variable profile provide it permits for a groove-type coupling. Moreover, the portion of the outer surface of the inlet fitting disposed to each side of the groove 266 defines an axial length and profile to permit the groove-type coupling. As is known in the art, a grooved coupling, such as for example Grinnell Grooved Fire Protection Products, Figure 772, Rigid Coupling as shown in Tyco Fire Building Products Technical Data Sheet TFP1950 (July 2004) can be used to couple a fitting, e.g., the inlet fitting 20, with the piping network or another fitting, such as for example, a T-fitting that similarly includes a counterpart groove. For the dry sprinkler 10 having a preferred nominal K-factor of 16.8 GPM/(PSI).sup.1/2, the inlet fitting 20 and the clamp groove 266 are sized to a preferred minimum nominal 2 inch size pipe for coupling to a correspondingly sized pipe or pipe fitting. However, the inlet fitting and its clamp groove can be alternatively sized to be smaller or larger to provide a dry sprinkler with a K-factor other than a nominal 16.8 GPM/(PSI).sup.1/2, provided the resultant dry sprinkler can provide the desired sprinkler flow performance as described herein. Because the stop surface 202 abuts the mating pipe fitting when forming a groove-type pipe coupling connection therebetween, the portion of the inlet fitting 20 proximal of the stop surface 202 is preferably configured for insertion within the inside diameter of the grooved pipe or pipe fitting to which the dry sprinkler 10 is coupled, as seen for example, in FIG. IB.

[0042] The external threads 204 of the dry sprinkler 10 are used in forming a preferred threaded connection between the dry sprinkler and a fluid supply piping network. The transition portion 206 provides a preferred stop that limits relative threaded engagement between the inlet head 20 and the supply pipe or pipe fitting. The inlet end 12 of the fitting 20 and the threads 204 are preferably configured with American National Standard Taper Pipe Thread (NPT) under ANSI/ASME B1.20.1-1983. For example, the inlet fitting threads 204 are preferably formed as at least one of ¾ inch, 1 inch, 1.25 inch NPT and/or international Standard ISO 7-1 (3d. ed., 1994). For a threaded-type coupling installation as shown for example in FIG. 1A, the fluid supply piping fitting BL may be an internally threaded T-Fitting or union with a nominally sized internal thread for complimentary threaded engagement with the external thread 204. In one particular embodiment of the threaded-type coupling installation, the nominal size of the internal thread of the fluid supply pipe fitting is smaller than the external diameter of the distal body portion 260 and more particularly smaller than the external diameter of the transition portion 206. In order that the proximal end of the inlet fitting 20 having the threads 204 can be inserted within the mating pipe fitting in the case of forming a groove-type coupling connection, the size of the fitting threads 204 are preferably a function of the grooved coupling size. More specifically, the thread diameter is maximized yet sized to fit inside fluid supply pipe or fitting. For example, where the groove 266 of the inlet fitting is sized for coupling to a nominal two inch pipe, the inlet fitting thread 204 is at a maximum 1¼ inch NPT. Accordingly the external thread 204 diameter of the inlet fitting is preferably less than the transition portion 206 external diameter.

[0043] With reference to FIGS. 2 and 3, the inlet fitting 20 preferably includes an inner surface 20c which defines and cinctures a proximal part of the passageway 18a and more preferably: (i) defines a preferred entrance surface 222, (ii) defines a sealing surface 224 for contacting an internal sealing assembly in the unactuated state of the dry sprinkler, and/or (iii) defines an internal chamber of the inlet for housing the internal sealing assembly and/or other internal components of the sprinkler when the dry sprinkler 10 is in the actuated state such that the fluid flows from the outlet to provide at an expected rate for the given inlet pressure. Like reference numerals refer to like features unless otherwise provided. According to the preferred embodiments shown in FIGS. 2 and 3, features of the inlet fitting inner surface 20c and the passageway 18a preferably define two or more sections within the inlet fitting 20 and more preferably define four sections I, II, III and IV that are each cinctured by different surfaces of the inlet fitting inner surface 20c. Section I preferably defines the inlet portion of the passageway 18a of the inlet fitting 20 preferably proximal to the transition portion 206 between the entrance surface 222 and the sealing surface 224. Section II preferably defines an expanding region of the passageway to transition distally from Section I between the sealing surface 224 and the widest portion of the interior of the inlet fitting 20 and the passageway 18a of Section III of the inlet fitting. Section IV preferably converges narrowly in the axial direction toward the distal end of the fitting 20 and the casing tube 22. The inlet fitting inner surface 20c can be alternatively configured provided the resultant profile of the passageway 18a in the inlet fitting 20 facilitates the desired fluid flow therethrough. In one preferred aspect, the proximal portion of the passageway 18a defined by the inner surface 20c is coaxially aligned and more preferably symmetrically disposed about the longitudinal axis A-A.

[0044] The preferred inlet fitting 20 of FIG. 3 is preferably a singular, integrated piece constructed of a homogenous material having the fitting threads 204, the clamp groove 266, and the head 268. The inlet fitting 20 is preferably cast or forged and machined as a single component having a head portion 220 and a larger body portion 260. The head portion 220 is preferably cast or forged and machined to include the desired external threads 204 and internal inlet surface 222. The body portion 260 preferably is cast and machined to include the external groove 266 for the groove-type coupling, and internally machined to include the internal thread proximate the distal end portion of the fitting 20 along with the surface profile defining the sealing surface 224 and varying sections of the passageway 18a.

[0045] Alternatively, the inlet fitting 20′, as shown in FIG. 2, includes a separate inlet head 220′ and inlet body 260′ which are coupled to one another to provide, in combination, the fitting threads 204, the clamp groove 266, and the head 268. Relative threaded engagement between the inlet head 220 and the inlet body 260 preferably includes coupling threads 20d on the inlet fitting outer surface 20b of the inlet head 220 that cooperatively engage coupling threads 20e on the inlet body 260. With reference to FIG. 2, the longitudinal positions of the coupling threads 20e on the inlet fitting inner surface 20c and the groove 266 on the inlet fitting outer surface 20b are offset or longitudinally spaced from one another so as to provide the inlet body 260 with a wall thickness that is adequate to avoid structural deformation and/or failure when coupling the dry pipe sprinkler 10 to the piping network (not shown) using either one of the fitting threads 204 or the clamp groove 266.

[0046] Referring to FIGS. 2 and 3, a preferred inlet entrance surface 222 defines the internal surface profile over which fluid is introduced into the dry sprinkler 10. The inlet entrance surface 222 can define various profiles leading to the sealing surface 224. As shown in FIG. 2, the preferred inlet entrance surface 222 defines a radiused profile and more preferably a convex profile with respect to the longitudinal axis A-A to form a compound curved surface intersecting a generally planar sealing surface 224. In an alternative profile as seen in FIG. 3, the inlet entrance surface 222 can be substantially a frustoconical surface disposed about the longitudinal axis A-A that has, in a cross-sectional view, a profile converging towards the longitudinal axis A-A and intersecting the inner surface defining the generally planar sealing surface 224. Preferably, the profile is linear; however, the profile could be, for example, stepped.

[0047] The axial location of the sealing surface 224 along the longitudinal axis A-A can define the type of system, wet or dry, to which the dry sprinkler 10 can be preferably coupled to. For example, where the sealing surface 224 of the inlet fitting 20, as shown in FIGS. 1C, ID and 3, is located at an axial distance below the inlet end 12 of the fitting 20 to define a volume of the passageway I8a proximal the sealing surface 224. The dry sprinkler 10 of FIGS. 1C and ID is preferably configured for installation in a wet system. In one particular embodiment, a portion of the external threads 204 extend proximally of the sealing surface 224. However, where the sealing surface 224 is axially located such that the sealing assembly of the sprinkler 10 can prevent any fluid accumulation over the inlet surface 222 in the unactuated state of the sprinkler, as seen for example in FIG. 2 and FIG. 8, explained in greater detail below, the dry sprinkler 10 is preferably configured for installation in either a wet system or a dry system.

[0048] In the preferred embodiment of the inlet fitting 20′ of FIG. 2, the sealing surface 224 is axially located in Section I along the axis A-A, preferably between the entrance surface 222 and the start of fitting threads 204. Alternatively, the sealing surface may be axially located in the head portion 220 of the inlet fitting such that the external threads 204 extend distally of the sealing surface 224. Because the preferred configuration of the inlet fittings threads 204 define the minimum diameter of the inlet fitting 20, the sealing surface 224 diameter is minimized. For a maximum pipe thread diameter of 1¼ inch diameter of the fitting thread 204, the sealing surface defines a preferred internal opening with a diameter of about one inch (1 in.). In the preferred embodiment of the inlet fitting 20 of FIG. 3, the sealing surface 224 is preferably axially located along the body portion 260 of the fitting substantially axially in line with the enlarged transition portion 206 between the end of the external fitting threads 204 and the external clamp groove 266. For a preferred two inch (2 in.) diameter transition portion 206 and more particularly nominal two inch external pipe groove 266, the sealing surface 224 preferably defines a preferred internal opening diameter of about 1¼ inch.

[0049] For the preferred outer structure assembly is of FIGS. 1C and ID, the casing tube 22 extends between an inlet fitting end 24 and an outlet frame end 26. The casing tube 22 has a casing tube inner surface 22a that cinctures part of the passageway 18a. The second coupling threads 22c are disposed proximate the inlet fitting end 24, and the third coupling threads 22d are disposed proximate the outlet frame end 26. The casing tube inner surface 22a preferably includes an interior groove 28a disposed along the longitudinal axis A-A axially proximate to the third coupling threads 22d, and the casing tube outer surface 22b preferably includes an exterior groove (not shown) disposed along the longitudinal axis A-A axially proximate to the second coupling threads 22c.

[0050] According to the preferred embodiment shown in FIG. ID, a casing tube outer surface 22b has complementary second coupling threads 22c formed proximate the inlet 12 that cooperatively engage first coupling threads 20a of the inlet fitting 20. The outer casing tube surface 22b preferably also has third coupling threads 22d formed proximate the outlet 14 that cooperatively engage fourth coupling threads 30a of the outlet frame 30. Alternatively, the casing tube 22 can be coupled to inlet fitting 20 and outlet frame 30 by any suitable technique, such as, for example, crimping, bonding, welding, or by a pin and groove. According to the preferred embodiment, the inlet fitting 20 is provided with first coupling threads 20a so that the inlet fitting 20 can be coupled to the second coupling threads 22c on the casing tube 22. Due to the preferably narrowing taper of the inlet fitting 20 from the transition portion 206 to the smaller distal end portion 268, the casing tube 22 has a preferably smaller diameter over its length than the transition portion 206. For example, where the transition portion 206 and groove 266 are sized for coupling to a nominal two inch pipe fitting, the casing tube 22 is preferably constructed with a nominal 1¼ inch diameter pipe, Schedule 10 galvanized steel pipe. Alternatively, the inlet fitting 20 and the casing tube 22 can be formed as a unitary member such that first and second coupling threads 20a and 22c are not utilized. For example, the casing tube 22 can extend as a single tube from the inlet 12 to the outlet 14. Alternatives to the threaded connection to secure the inlet fitting 20 to the casing tube 22 can also be utilized such as other mechanical coupling techniques, ch can include crimping or bonding.

[0051] Various configurations of the outlet frame 30 can be used with the dry sprinklers lo according to the preferred embodiments. Any suitable outlet frame 30, however, may be used so long as the outlet frame 30 positions a fluid deflecting structure 40 preferably axially spaced from the outlet 14 of the dry sprinkler 10 at a preferably fixed distance. A preferred outlet frame 30 is shown in the dry sprinkler assembly 10 in FIG. 1C. FIG. 4 shows the preferred outlet 30 in greater detail.

[0052] According to the preferred embodiment shown in FIG. 4, the outlet frame 30 has an outlet frame outer surface 30b and an outlet frame inner surface 30c, which surfaces cincture part of the passageway 18a. The outlet frame outer surface 30b can be provided with the coupling threads 30a formed proximate a casing tube end 32 of the outlet frame 30. The coupling threads 30a preferably cooperatively engage the coupling threads 22d of the casing tube 22. The outlet frame 30 inner surface 30c defines a bore 34 cincturing the passageway 18a at the casing tube end 32 of the outlet frame 30.

[0053] Referring again to FIG. 1C, a free end of the outlet frame 30 can include at least one frame arm 38 that is coupled to the fluid deflecting structure 40. Preferably, the outlet frame 30 and frame arm 38 are formed as a unitary member. The outlet frame 30, frame arm 38, and fluid deflecting structure 40 can be made from rough or fine casting, and, if desired, machined. Referring to FIG. 1C, the fluid deflecting structure 40 may include an adjustment screw 42 and a planar surface member 44 coupled to the frame arm 38 and preferably fixed at a spaced axial distance from the outlet frame 30. Accordingly, as shown, the preferred outlet frame 30 and deflecting structure 40 provide for a pendent dry sprinkler configuration. The planar surface member 44 is configured to deflect the fluid flow to form an appropriate spray pattern. Instead of a planar surface member 44, other configurations could be employed to provide the desired fluid deflection pattern. However other deflecting structures and dry sprinkler configurations are possible, such as for example, a sidewall deflector can be used to provide for a horizontal sidewall sprinkler. The adjustment screw 42 is provided with external threads 42a that can be used to adjust an axial spacing between the inner structure assembly 50 and the thermal trigger 80. The adjustment screw 42 preferably includes a seat portion 42b that engages the thermal trigger 80. Although the adjustment screw 42 and the planar surface member 44 have been described as separate parts, they can be formed as a unitary member.

[0054] The inner structural assembly 50 of dry sprinkler permits fluid flow between the inlet 12 and the outlet 14. The inner structural assembly 50, preferably, is disposed within the tubular outer structure assembly 18. The terms “tube” or “tubular,” as they are used herein, denote an elongate member with a suitable cross-sectional shape transverse to its longitudinal axis, such as, for example, circular, oval, or polygonal. Preferably, each of the inlet fitting 20 and inner structure assembly 50 can be made of a copper, bronze, brass, galvanized carbon steel, carbon steel, or stainless steel material. Moreover, the cross-sectional profiles of the inner and outer surfaces of a tube may be different. According to the preferred embodiment shown in FIGS. 1C, ID and 5, the inner structural assembly 50 includes a fluid tube 52, a guide tube 56, a trigger seat 58, and a seal assembly 60. In the preferred configuration of the dry sprinkler 10, the seal assembly 60 is engaged with or coupled to the fluid tube 52, and the fluid tube 52 is engaged with or coupled to the guide tube 56, and the guide tube 56 is engaged with or coupled to the trigger seat 58. For the preferred outer structure assembly having the preferred dual connection fitting, any internal assembly may be used provided its operation upon actuation of the dry sprinkler provides the necessary flow.

[0055] According to the preferred embodiment shown in FIGS. 1C and ID, the fluid tube 52 includes a tubular body extending along the longitudinal axis A-A between a seal assembly end 52a and a guide tube end 52b. The longitudinal length of the fluid tube 52 preferably corresponds to or is substantially the same as that of the casing tube 22. For a preferred nominal 1½ inch casing tube 22, the fluid tube 52 is preferably constructed from 1.125 in. (Inner Diameter)×1.25 in. (Outer Diameter) preferably stainless steel tubing. The overall length of the dry sprinkler 10 can be selected for preferably locating the outlet frame 30 at a desired distance from a fluid supply pipe, for example, a ceiling, a wall, or a floor of an enclosed area. The overall length can be any value, and is preferably between about two to about fifty inches, more preferably ranging from a minimum of about 9 inches to about 48 inches or other fixed length, depending on the application of the dry sprinkler 10. In one embodiment, the casing tube 36 may define a nominal axial length from its proximal end to its distal end ranging from about 1.5 inches to about 40.5 inches.

[0056] The fluid tube 52 can include additional features which facilitate flow through the tube and/or assist in maintaining the substantially centered axial alignment of the tube 52 along the passageway 18a. As shown for example in FIG. 5, the fluid tube 52 preferably includes one or more spaced apart apertures or openings 52c located between the ends of the tube for introducing fluid into the fluid tube 52. In addition, the fluid tube may include one or more surface features which can act against the casing tube 22 to maintain the fluid substantially centrally aligned along the passageway 18a. For example, the fluid tube 52 may include one or more spaced apart surface features, projections, dimples, ridges or bumps 52d, preferably formed in the tube 52, such that the projection 52d contacts the inner surface of the casing tube 22 to maintain the fluid tube substantially centrally axially aligned within the casing tube 22. Although the surface features 52d are shown in FIG. 5 as being formed in the tube, the surface features may be separate structures that are attached or affixed to the fluid tube. The surface features 52d are preferably sized and located so as not to greatly interfere with the desired flow and performance characteristics of the dry sprinkler 10. By substantially maintaining the fluid tube in proper axial alignment along the passageway 18a, the surface features 52d can stabilize the internal structure of the dry sprinkler 10 during shipping and/or transport.

[0057] According to the preferred embodiment shown in FIGS. 1C, ID and 4, the guide tube 56 also includes a tubular body extending along the longitudinal axis A-A between a proximal fluid tube end 56a and a distal outlet frame end 56b. The trigger seat end 56b preferably has an outside diameter sized to smoothly slide in the bore 34 of the outlet frame 30. The fluid tube end 56a of the guide tube 56 preferably has an outer surface sized to engage the proximal inlet surface of the outlet frame 30 as a stop surface. With reference to the unactuated dry sprinkler shown in FIG. 1C, the axial distance between the proximal end surface of the outlet frame 30 and the enlarged fluid tube end 56a defines the preferred axial travel of the inner structural assembly 50 upon actuation of the sprinkler. The fluid tube end of the guide tube 56 has an inside diameter sized to receive the guide tube end 52b of the fluid tube 52. The guide tube 56 has a guide tube inner surface 56c that preferably cinctures the passageway I8a in the guide tube 56.

[0058] According to the preferred embodiment shown in FIG. 4, the trigger seat 58 can include a disk member extending along the longitudinal axis A-A between the guide tube end 58a, and a thermal trigger end 58b. In the unactuated position of the dry sprinkler 10 (FIG 1C), the guide tube end 58a of the trigger seat 58 is coupled, e.g., contiguously abuts, the trigger seat end of the guide tube 56, and the thermal trigger end 58b can include a nub portion 58c. The nub portion 58c preferably has an interior cavity configured to contiguously engage a terminal end of the thermal trigger 80, which controls displacement of the inner structural assembly 50 relative to the outer structure assembly 18.

[0059] The thermal trigger 80 is disposed proximate to the outlet 14 of the dry sprinkler 10. Preferably, the thermal trigger 80 is a solder link used in combination with a strut 80a and lever 80b Alternatively, the thermal trigger 80 is a frangible bulb that is interposed between the nub portion 58c on the trigger seat 58 and a seat portion 42b of the adjustment screw 42, as seen for example, in FIG. 4A. Instead of a frangible bulb 82 or a solder link, the thermal trigger 80 may be any suitable arrangement of components that reacts to the appropriate condition(s) by actuating the dry sprinkler 10.

[0060] The thermal trigger 80 operates to: (1) maintain the inner assembly 50 in the unactuated state of the dry sprinkler 10 over a preferred first range of temperatures between about minus 60 degrees Fahrenheit to about just below a temperature rating of the thermal trigger 80 so as to maintain the seal assembly 60 in a fluid tight sealed position against the sealing surface 224; and (2) permit the inner assembly 50 to move along the longitudinal axis A-A over a second range of temperatures at or greater than the temperature rating of the thermal trigger 80 so as to place the dry sprinkler 10 in an actuated state with the seal assembly 60 at an axial position within the inlet fitting 20 such that fluid flows from the sprinkler at an anticipated rate for the given starting fluid pressure at the inlet of the sprinkler and the rated K-factor of the dry sprinkler. More specifically, based on the rated K-factor of the dry sprinkler 10 of the preferred embodiments, the dry sprinkler 10 allows for an actual minimum flow rate in gallons per minute (GPM) through the outlet as a product of the rated K-factor and the square root of the pressure in pounds per square inch gauge (psig) of the fluid fed into the inlet 12 of the dry sprinkler 10. The preferred dry sprinkler 10 has a preferred actual minimum flow rate from the outlet 14 of approximately equal to 95% of the magnitude of a rated. K-factor times the square root of the pressure of the flow of fluid fed into the inlet 12 of each embodiment. The dry sprinkler 10 has a preferred rated discharge coefficient, or rated K-factor, that is greater than 14 GPM/PSI.sup.1/2 and is preferably 16.8 GPM/PSI.sup.1/2 or greater. Accordingly, the sprinkler 10 can have a nominal K-factor being any one of 16.8 GPM/PSI.sup.1/2, 19.6 GPM/PSI.sup.1/2, 22.4 GPM/PSI.sup.1/2, 25.2 GPM/PSI.sup.1/2, 28.0 GPM/PSI.sup.1/2, 33.6 GPM/PSI.sup.1/2 or greater at 50% increments over 5.6 GPM/PSI.sup.1/2. However, any suitable nominal value for the K-factor could be provided for the dry sprinkler of the preferred embodiments.

[0061] The temperature rating of the thermal trigger 80 can be a suitable temperature such as, for example, about a nominal 135, 155, 165, 175, 200, 214 or 286 degrees Fahrenheit and plus-or-minus (+/−) 20% of each of the stated values. The thermal trigger 80 is further preferably defined by its thermal sensitivity and more particularly by its Response Time Index (RTI) to measure the rapidity with which the thermal trigger 80 operates in a specific sprinkler assembly as measured under standardized test conditions provided by, for example, Underwriters Laboratories (UL), NFPA 13 provides that sprinklers defined as fast response have a thermal element with an RTI of 50 (meters-seconds).sup.1/2 or less; and sprinklers defined as standard response have a thermal element with an RTI of 80 (meters-seconds).sup.1/2 or more. The dry sprinkler 10 and its thermal trigger 80 can have an RT1 so as to be either a fast response or a standard response sprinkler so as to provide suitable fire protection for a given dry sprinkler installation.

[0062] In an unactuated state of the dry sprinkler 10, the inner structural assembly 50 is supported against a portion of the outer structure assembly 18 so that the seal assembly 60 of the inner structure assembly 50, contacts the sealing surface 224 of the inlet fitting 20. Referring to FIGS. 1C, ID and 5, the seal assembly 60 preferably includes a metallic annulus or disc spring seal 680, e.g., a Belleville spring, which contacts the sealing surface 224 on the inlet fitting 20 in the unactuated position of the dry sprinkler 10. Accordingly, the spring seal 680 preferably provides both a biasing force and a fluid seal. The seal assembly 60, in conjunction with the sealing surface 224 of the inlet fitting 20, can form a seal against fluid pressure proximal at or above the sealing surface 224 at any start pressure from approximately zero to approximately 175 psig so that the portion of the passageway 18a distal of the sealing surface 224 is generally free of the fluid disposed above the seal when in an unactuated state. The start pressure, i.e., an initial pressure present at the inlet 12 when the dry sprinkler 10 is actuated, can be at various start pressures. The start pressure is at a preferred minimum five pounds per square inch (5 psig.) and may range from about 5 psig. to about 175 psig.

[0063] The spring seal 680 is preferably biased from the sealing surface 224 as the spring seal 680 forms a generally truncated cone generally coaxial with the longitudinal axis A-A. The inner structural assembly 50 may optionally include a biasing member, for example, a spring as shown and described in U.S. Pat. No. 7,559,376 (FIG. 1A, spring 55). In a preferred embodiment, this biasing member extends between the outer structural assembly 18 and the inner structural assembly 50 to bias the inner structural assembly 50 from its position in the unactuated state of the dry sprinkler 10 to its actuated position in the open configuration of the dry sprinkler 10. The force of this biasing member adds to the force of a spring seal 680 of the preferred seal assembly 60 in the closed configuration of the dry sprinkler 10 and adds to the force of the flowing fluid in the open configuration of the dry sprinkler 10.

[0064] In operation, when the thermal trigger 80 is actuated, the thermal trigger SO separates from the dry sprinkler 10. The separation of the thermal trigger 80 removes the support for the inner structural assembly 50 against the resilient spring force of the preferred spring seal 680 and/or the pressure of the fluid at the inlet 12. Consequently, the spring seal 680 separates from the sealing surface 224 as the inner structural assembly 50 translates along the longitudinal axis A-A toward the outlet 14 to its fully actuated position, as shown for example, in FIG. ID. In the preferred embodiment in which the seal assembly 60 is affixed to the fluid tube, the seal assembly and fluid tube remain at a fixed distance relationship in the translation of the inner structurally assembly 50 from the unactuated to the actuated positions. Moreover, in one aspect the seal assembly 60 remains aligned along the longitudinal axis in each of the unactuated and actuated positions of the inner structurally assembly 50. In another preferred aspect, the interior chamber defined by the inner surface of the inlet fitting 20 remains symmetric about the inner structurally assembly 50.

[0065] The axial force provided by the spring seal 680 assists in separating the inner structural assembly 50 from the sealing surface 224 of the inlet fitting 20. With the seal assembly 60 spaced from the sealing surface 224 and preferably located in Section III of the inlet fitting 20, water or another suitable firefighting fluid is allowed to flow through the inlet 12, through the casing 22 and fluid tube 52, out the outlet 14 and impact the planar surface member 44 or another form of deflector distributes the fluid flow over a protection area below the dry sprinkler 10.

[0066] The preferred sealing surface 224 of the inlet fitting 20 of FIG. 5 preferably defines an inner diameter of about 1.2 inch. Accordingly, the outer diameter of the spring seal 680 is preferably slightly larger at about 1.3 inches to define area of about 1.3 square inches. Upon sprinkler actuation, the inner assembly preferably locates the spring seal 680 in Section III of the passageway 18a of the inlet fitting 20 at a preferred axial distance of about 0.45 inches below the sealing surface 224. Section III of the passageway 18a preferably defines a diameter of about two inches (2 in.), which corresponds to a cross-sectional area of the passageway through Section III being about 3.1 square inches. Subtracting the surface area projection defined by the spring seal 680 from the area defined by Section III defines an annular opening having a preferred area of slightly less than two square inches (2 sq. in) through which fluid may flow. Preferred seal surface 224 defines a preferred ratio of the seal surface opening diameter to the Section III diameter to be about 0.6. With an attached sprinkler frame 30 haying an outlet 14 with a preferred diameter of about 0.95 inches, it has been determined for a fluid delivery to the inlet 12 of the sprinkler, the preferred dry sprinkler 10 experiences an internal fluid flow and discharge profile that defines a K-factor value of about 17.29 GPM/(PSI).sup.1/2 for the dry sprinkler, which is in the K-factor range of a nominal K-factor 16.8 GPM/(PSI).sup.1/2.

[0067] It has been determined that the K-factor of the preferred dry sprinkler can be altered by a small structural changes in the sprinkler. For example, where the outlet 14 diameter is increased by about 18% to about 1.125 inches and the sealing assembly 60 axial displacement is increased by about 67% to 0.75 inches below the sealing surface 224, the preferred dry sprinkler 10 experiences an internal fluid flow and discharge profile that defines a K-factor value of about 20.47 GPM/(PSI).sup.1/2 a fluid delivery to the inlet 12 of the sprinkler. The K-factor of 20.47 GPM/(PSI).sup.1/2 falls within the K-factor range of a nominal K-factor of 19.6 GPM/(PSI).sup.1/2. Thus, it has been shown for a fractional increase in the structural dimensions of the preferred thy sprinkler, an increase by one nominal K-factor can be realized. Further modifications of the parameters of the inlet fitting can provide for the desired K-Factor. Alternatively in combination with such changes, the inlet size can be increased to achieve various K-factors. Such parameters include changes to the nominal external thread and groove diameters of the inlet fitting in combination with changes in the internal diameters defined by the internal surface of the inlet fitting and features of the internal structural assembly. For one preferred embodiment of a dry sprinkler having an inlet fitting, such as shown in FIG. 3, with an external thread diameter of 1.5 inches and an external groove diameter is nominally 2.5 inches, a nominal K-factor of 25 GPM/(PSI).sup.1/2 can be provided when combined with an internal surface defining a minimum inlet surface diameter in the proximal head portion of about 1.3 inches, a nominal fluid tube diameter of 1.5 inches and an outlet diameter of 1.4 inches. For the preferred K-25 sprinkler, the internal assembly included a seal spring having a diameter of 1.5 inches with an axial translation distance of about 0.75 inches in translation from the seal surface to an actuated position within the inlet fitting.

[0068] As discussed above, the axial location of the sealing surface 224 within the inlet fitting 20 can define a preferred installation of the dry sprinkler 10 into one of: (i) a wet only system installation; or (ii) a wet or dry system installation. FIGS. 1C, ID, 5, 6, and 7 showed preferred embodiments of a dry sprinkler 10 having an inlet fitting 20 with a sealing surface 224 for a preferably wet system installation. According to the preferred embodiments, the preferred spring seal 6,80 is disposed about a mounting member 620 that is preferably fixed to and more preferably at least partially disposed in the proximal end 52a of the fluid tube 52. Preferably, the coupling between mounting member 620 and fluid tube 52 can include a weld, adhesive, a pin, a threaded-type coupling, an interference coupling, or any coupling technique suitable for fixedly coupling the mounting portion 620 with the fluid tube 52.

[0069] The preferred mounting member 620 includes a diverting portion 620a formed integrally with the mounting portion 620b. The diverting portion 620a preferably defines a surface conical profile to engage and support the spring seal 680 and divert incoming fluid flow about the inner assembly 50. More preferably, the diverter portion preferably extends through the central opening of the seal 680 such that the spring seal is located substantially at the transition between the mounting portion 620b and the diverting portion 620a. The preferred conical diverting portion 620a defines in cross-section height h being preferably about 0.5 inches, and the angle of inclination of the conical face 662″ with respect to longitudinal axis A-A is preferably about 70 degrees. The mounting member 620 is preferably hollowed so as to define an interior volume that commingles the interior of the fluid tube 52 when the member 620 is affixed to the tube end 52a. The preferred hollowed structure of the mounting member 620 reduces the weight/mass of the member and the inner assembly 50 as a whole.

[0070] An alternative construction of the mounting member 620 is shown in FIG. 6. More specifically, the mounting portion is shown as a substantially solid member. More preferably, the mounting member 620″ includes a diverter element 620a″ coupled to a separate mounting element 620b″. The spring seal 680 is preferably disposed between the diverter element 620a″ and the mounting element 620b″. The separate elements are shown being threaded to one another, but they may be coupled or affixed to one another by alternative means. In the mounting member 620 configuration of FIG. 5 or FIG. 6, the mounting portion is affixed to the fluid tube 52 such that the mounting portion 620 is not displaced with respect to the fluid tube 52.

[0071] Respectively shown in FIGS. 8 and 8A, is an alternate embodiment of the dry sprinkler 10′ in an unactuated and actuated state that is configured for wet or dry system installation. The dry sprinkler 10′ is shown with the inlet fitting 20 of FIG. 2 in which the sealing surface 224 is located axially proximal to or substantially adjacent to the inlet fitting threads 204 in Section I and more specifically between the entrance surface 222 and the axial start of the fitting threads 204. Accordingly, to properly locate the seal assembly 60 within the preferred Section III inlet fitting 20, the seal assembly requires a longer axial displacement from the sealing surface 224 as compared to the dry sprinkler 10 embodiment of FIGS. 1 and 1A.

[0072] The preferred sealing surface 224 of the inlet fitting 20 of FIG. 8 preferably defines an inner diameter of about one inch (1 in.) and more specifically defines an inner diameter of approximately 0.952 inches, which corresponds to an area of about 0.712 square inches defined by the opening at the sealing surface. Accordingly, the outer diameter of the spring seal 680 is preferably about 1.000 inch, which corresponds to a 0.785 square inch surface area projection. Upon sprinkler actuation, the yoke sub-assembly 600 locates the spring seal 680 in section III of the passageway 18a of the inlet fitting 20. Section III of the passageway 18a preferably defines a diameter of about two inches (2 in.), which corresponds to a cross-sectional area of the passageway through Section III being about three square inches. Subtracting the surface area projection defined by the spring seal 680 from the area defined by Section III defines an annular opening having an area of about two square inches (2 sq. in) through which fluid may flow.

[0073] To provide the desired axial displacement of the seal assembly 60, the dry sprinkler 10 includes a contractible inner assembly 50′ in which the seal assembly 60 preferably includes a yoke sub-assembly 600. The yoke sub-assembly 600 preferably provides for relative axial displacement between the seal assembly 60 and the fluid tube 52. Accordingly, between the two preferred embodiments of the dry sprinkler 10, 10′ shown in FIG. 1C and FIG. 8, the thermal trigger 80, fluid guide tube 56 and fluid tube 52 can have the same axial displacement relative to the outer structural assembly 18 of the dry sprinkler; thus minimizing or eliminating the need for maintaining different sized casing tubes for the two embodied sprinklers 10, 10′. The yoke sub-assembly 600 provides the additional axial displacement of the seal assembly 60 for proper operation and fluid flow from the dry sprinkler 10′. Although the contractible inner assembly 50′ is suited for use in with the dual coupling arrangement of the preferred inlet fitting 20 described above and shown in FIG. 2, it should be understood that the preferred inner assembly 50′ and yoke subassembly 600 can be used with any dry sprinkler in which relative axial displacement is required between the seal assembly 60 and the fluid tube 52, regardless of the number of coupling arrangements of the inlet fitting 20.

[0074] According to the preferred embodiment shown in FIGS. 8 and 8A, the seal assembly 60 preferably includes a yoke sub-assembly 600. More specifically, the yoke subassembly 600 shown in FIG. 9 is preferably configured with the mounting portion 620b′ as a yoke 610 with preferably four levers 640 pivotally coupled to the mounting member 620 by, for example, four respective dowel pins 650, the diverter 620a′ and the spring seal 680. Referring additionally to FIG. 9A, the yoke 610 includes a tubular body that extends along the longitudinal axis A-A between a proximal end 610a and a distal end 610b. Distributed around a peripheral surface 610c of tubular body 610 is a plurality of windows or openings 614 that each extend longitudinally from near the proximal end 610a toward the distal end 610b, and further preferably includes four windows 614 disposed equiangularly about the longitudinal axis A-A. Each window 614 in the peripheral surface 610c provides an opening to a chamber 616 in the tubular body 612. Preferably, individual channels 618 lead from each window 614 to the chamber 616 in the center of the tubular body 610.

[0075] Referring to FIGS. 9, 9A and 9B, individual levers 640 are pivotally pinned in each of the channels 618. Preferably, the pivot action of the levers 640 is provided by dowel pins 650 extending from opposite sides of an individual lever 640 and into corresponding sockets 618a on opposite sides of a corresponding channel 618. The sockets 618a preferably extend between the channels 618 and facets 610d of the peripheral surface 610c. Accordingly, individual dowel pins 650 extend along respective pivot axes B-B through portions of the tubular body 610 and through individual levers 640.

[0076] Preferably, each lever 640 pivots about axis B-B between a first orientation in which the lever 640 extends substantially perpendicular to the longitudinal axis A-A in the unactuated state of the sprinkler 10′ of FIG. 8, to a second orientation in which the lever 640 is substantially parallel to the longitudinal axis A-A in the actuated state of the sprinkler 10′ of FIG. 8A. The levers 640 are placed in their first orientation by the contact with the inner surface of the inlet fitting 20 at a first lever distance from the pivot axis B-B, and by the contact with the fluid tube 52 at a second lever distance from the pivot axis B-B. The first lever distance is preferably greater than the second lever distance. Accordingly, in the unactuated arrangement of the yoke sub-assembly 600, the fluid tube 52 bears one surface of the lever 640 and an inner surface of the inlet fitting 20, for example transverse surface 234, bears on an opposing surface of the lever 640 to place the levers 640 in their first orientation outside of the channels 618. The levers perpendicular orientation support the yoke assembly atop the fluid tube 52 such that axial length of the inner assembly 50 is maximized within the passageway 18 and the seal spring 680 is in contact with the sealing surface 224. In the unactuated state of the dry sprinkler 10′, the diverting clement 620a′ extends above the sealing surface substantially adjacent the inlet and proximal end of the fitting 20. The conical face of the diverting element 620a′ minimize and preferably prevents fluid from icing over above the sealing surface 224 by substantially occupying the space above the sealing surface, as seen in FIG. 8, where fluid may otherwise collect. Accordingly, the arrangement of the dry sprinkler 10′ is well suited for either wet or dry system installation.

[0077] In the actuated arrangement of the dry sprinkler 10′ and the yoke sub-assembly 600, operation of the thermal trigger 80 causes an initial axial displacement of the inner structural assembly 50 along the longitudinal axis A-A toward the outlet 14. The preferred axial displacement is defined by the axial length between the top of the outlet frame 30 and the proximal end of the guide tube 65 in the unactuated state of the sprinkler. This initial movement permits the lever 640 to separate from the surface 234 of the inlet 20, allowing the levers 640 to pivot about the pivot axes B-B into their second orientation and into their respective channels 618. The contraction or collapse of the levers 640 into the channels 618 axially displace the yoke sub-assembly 600 along the longitudinal axis A-A relative to the fluid tube 52. More specifically, the levers 640 pivot so as to remove support of the yoke 610 such that the yoke 610 is axially displaced within the tube 52. In one preferred embodiment of actuation of the sprinkler 10′, the fluid tube 52 axially translates from the sealing surface at a first distance. Pivot of the levers 640 provide that the yoke sub-assembly 600 axially translates from the sealing distance at a second distance greater than the first distance.

[0078] Referring again to FIGS. 9, 9A and 9B, the diverter portion 620a is provided at one, preferably upper end 610a of the tubular body 610 and includes a threaded mounting aperture 622. Surrounding the threaded mounting aperture 622 is a boss portion 624 that is sized to approximately correspond to an internal diameter of the spring seal 680, which preferably provides a fluid seal with respect to the boss portion 624 on the yoke sub-assembly 600. Surrounding the mounting portion 620b′ is a travel stop 630 portion preferably projecting radially from the peripheral surface of the tubular body 610. The travel stop 630 limits the distance that the yoke sub-assembly 600 travels along the longitudinal axis A-A inside of and with respect to the fluid tube 52 in the actuated arrangement of the yoke sub-assembly 600. The travel stop 630 shown preferably includes a ring circumscribing the tubular body 612; however, the travel stop 630 may alternatively include one or more projections for engaging the yoke sub-assembly end 52a of the fluid tube 52 to limit the distance that the yoke sub-assembly 600 is permitted to travel inside the fluid tube 52. Accordingly, the axial distance between the travel stop 630 and the proximal end of the fluid tube 52 in the unactuated state of the sprinkler 10 defines the axial travel of the yoke subassembly 600 relative to the fluid tube 52.

[0079] While the present invention has been disclosed with reference to certain embodiments, numerous modifications, alterations, and changes to the described embodiments are possible without departing from the sphere and scope of the present invention, as defined in the appended claims. Accordingly, it is intended that the present invention not be limited to the described embodiments, but that it has the full scope defined by the language of the following claims, and equivalents thereof.