Abstract
Method and apparatus for air flow regulation comprise a vertically oriented conduit, a sail assembly positioned in the conduit and moveable therewithin responsively to air flow through the conduit to regulate rate of air flow through the conduit and to stop air flow through the conduit upon air flow rate through the conduit exceeding a preselected value with a detector for sensing when the sail assembly has stopped air flow thought the conduit as a result of air flow rate exceeding said pre-selected value.
Claims
1. An air flow regulator comprising: a) a conduit; b) a sail assembly positioned in the conduit and movable therewithin responsively to air flow through the conduit to regulate air flow through the conduit.
2. The regulator of claim 1 further comprising: a) a detector for sensing when air flow through the conduit has stopped as a result of air flow rate exceeding said pre-selected value.
3. A method for regulating air flow, comprising: a) providing a conduit; b) positioning a movable sail assembly including a sail within the conduit; c) positioning a stop within the conduit; d) permitting the sail assembly to move responsively to air flow through the conduit between a position at which air flows around the sail assembly and through the conduit and a position at which the sail assembly contacts a stop and blocks air flow through the conduit; and e) detecting when the sail assembly contacts the stop to block air flow.
4. The method of claim 3 further comprising providing an electromagnetic beam for detection of when the sail assembly contacts the stop.
5. The method of claim 4 wherein the electromagnetic beam is a visible light beam.
6. The method of claim 4 wherein the electromagnetic beam is an infrared beam.
7. The method of claim 4 further comprising permitting the sail to tilt relative to the remainder of the sail assembly respecting the axis of the conduit.
8. The method of claim 3 further comprising providing a sail which is triangular.
9. The method of claim 3 further comprising providing a telescoping cylindrical member as a part of the sail assembly.
10. The method of claim 9 further comprising providing within the conduit a stationary baffle having a cylindrical outlet, and permitting the cylindrical member of the sail assembly to move telescopingly within the baffle cylindrical outlet.
11. Air flow regulating apparatus, comprising: a) a conduit; b) a second conduit telescopingly movable along and within the first conduit; c) a baffle for forcing air flow in the first conduit through the second conduit; d) a sail within the first conduit, connected to the second conduit and being movable responsively to air flow within the first conduit; e) a stop within and connected to the first conduit for regulating axial travel of the second conduit; and f) a detector for sensing when the second conduit contacts the stop.
12. Apparatus of claim 11 wherein the second conduit has an edge adapted for substantially air tightly contacting a sealing surface of the stop to preclude air flow through the second conduit upon the second conduit contacting the sealing surface.
13. Apparatus of claim 12 wherein the stop is perpendicular to axes of the first and second conduits.
14. Apparatus of claim 13 wherein the first and second conduits are coaxial and the first conduit is movable coaxially within the second conduit.
15. Apparatus of claim 13 wherein the stop is planar.
16. An air flow regulator comprising: a) a conduit; b) a pair of open-ended tubular-like segments within the conduit, an outer tubular segment being fixed and the other being slideably axially movable along the fixed segment; c) a plate extending partially across the interior of the conduit, positioned for contacting and limiting travel of the moveable tubular segment, the plate covering an outlet end of the movable tubular segment upon contact therewith; d) a sail connected to the moveable segment, positioned in the d upstream of the segments.
17. The air flow regulator of claim 16 wherein the segments are telescoping.
18. The air flow regulator of claim 16 wherein the tubular segments are cylindrical.
19. The air flow regulator of claim 16 wherein the surface of the plate contacted by the moveable tubular segment is planar.
20. The air flow regulator of claim 19 wherein the portion of the moveable tubular segment contacting the plate surface is annular.
21. The air flow regulator of claim 16 wherein a surface of the plate contacted by the moveable tubular segment is flat, the tubular segments are cylindrical, and a circular edge of the tubular segment contacting the plate surface is annular and normal to the axis of the tubular segment.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0117] FIG. 1 is a schematic representation of a resin delivery system with a single air flow regulator in accordance with aspects of the invention.
[0118] FIG. 2 is a schematic representation of a resin delivery system with a plurality of air flow regulators in accordance with aspects of this invention.
[0119] FIG. 3 is an isometric view of the exterior of an air flow regulator portion of apparatus for pneumatically conveying granular plastic resin as disclosed in U.S. Pat. Nos. 9,371,198 and 9,604,793.
[0120] FIG. 4 is a front elevation of the air flow regulator illustrated in FIG. 3.
[0121] FIG. 5 is an isometric sectional view of the air flow regulator illustrated in FIGS. 3 and 4, with the section taken at arrows 3-3 in FIG. 4.
[0122] FIG. 6 is a sectional view in elevation of the air flow regulator illustrated in FIGS. 3 and 5, with the section taken at lines and arrows 3-3 in FIG. 4, with air flow through the air flow regulator being depicted in FIG. 6 by curved dark arrows.
[0123] FIG. 7 is a sectional view in elevation, similar to FIG. 6, of the air flow regulator illustrated in FIGS. 3 through 6, but with the air flow regulator internal parts in position whereby there is no air entering the air flow regulator and hence there is no air flow upwardly through the air flow regulator, in contrast to the condition with such air flow shown in FIG. 6.
[0124] FIG. 8 is a sectional view in elevation, similar to FIGS. 6 and 7 of the air flow regulator illustrated in FIGS. 3 through 7, but with the air flow regulator internal parts in position where there is an excessive amount of air attempting to enter the air flow limited but there is no air flow upwardly through the air flow regulator due to the air flow regulator valve having moved to block air flow upwardly through the air flow regulator, in contrast to air flow upwardly through the air flow regulator as shown in FIG. 4.
[0125] FIG. 9 is an exploded isometric view of the air flow regulator illustrated in FIGS. 3 through 8.
[0126] FIG. 10 is an isometric view of the movable portion of the air flow regulator illustrated in FIGS. 3 through 9.
[0127] FIG. 11 is a sectional view of an air flow regulator similar to FIGS. 6, 7 and 8, illustrating an alternate construction of the baffle portion of the air flow regulator.
[0128] FIG. 12 is sectional view of the air flow regulator similar to FIGS. 6, 7, and 11, illustrating a second alternate construction of the baffle portion of the air flow regulator.
[0129] FIG. 13 is a sectional view in elevation, similar to FIG. 7, of an improved air flow regulator in accordance with the invention, with the air flow regulator internal parts in position whereby there is no air entering the air flow regulator, the sail assembly has not been lifted by any air flow, the electromagnetic beam passes through the air flow regulator without impinging on any internal parts and there is no air flow upwardly through the air flow regulator.
[0130] FIG. 14 is a sectional view in elevation of the air flow regulator illustrated in FIG. 13, with the air flow regulator internal parts in position whereby no air can flow through the air flow regulator due to those internal parts having blocked air flow due to instantaneous air flow exceeding the design value and with the electronic beam, which would normally go from an emitter to a detector, being blocked by the air flow regulator internal parts, thereby indicating that air flow has exceeded a maximum design value and has been halted.
[0131] FIG. 15 is a sectional view in elevation, similar to FIG. 7, of an adjustable air flow regulator in accordance with the invention, with the air flow regulator internal parts in position whereby a moderate amount of air is entering the air flow regulator, the sail assembly has been lifted by air flow, and the air flow regulator internal valve has not contacted a stop defining an intermediate valve position and hence an intermediate maximum air flow rate through the air flow regulator.
[0132] FIG. 16 is a sectional view in elevation of the adjustable air flow regulator illustrated in FIG. 15, with the stop illustrated in FIG. 15 withdrawn and the air flow regulator internal parts in position whereby no air can flow through the air flow regulator due to those internal parts now having blocked air flow due to instantaneous air flow exceeding the maximum design value.
DESCRIPTION OF THE PREFERRED EMBODIMENT AND BEST MODE KNOWN FOR PRACTICE OF THE INVENTION
[0133] In this application, unless otherwise apparent from the context it is to be understood that the use of the term vacuum means air at slightly below atmospheric pressure. The vacuum (meaning air at slightly below atmospheric pressure) provides a suction effect that is used to draw granular plastic resin material out of a supply and to convey that granular plastic resin material through various conduits to receivers where the granular resin material can be temporarily stored before being molded or extruded. Hence, in this application it is useful for the reader mentally to equate the term vacuum with the term suction.
[0134] This invention is based on the flow regulator disclosed and claimed in U.S. Pat. No. 9,371,198 referenced above and adds at least a sensor to detect when the regulator has stopped flow, or to detect other flow conditions, according to the location of the sensor.
[0135] When air flow is below the design limit, the regulator remains fully open. The moment air flow exceeds the design limit the regulator closes instantly and fully to the point at which it properly stops flow. The movement is sudden and complete. There is no intermediate modulation of the regulator. It does not close gradually nor does any air flow close it partially. For this reason it is easy to detect closing. The preferred way to do this is to place a photo detection device on one side of the regulator, so that it can detect when a beam of light is either blocked, or reflected by the valve closing. A clear window may be used, or the detection device can be mounted into the tubular wall of the regulator. Infrared lasers and other electromagnetic beam based devices may also be used.
[0136] Referring to the drawings in general and to FIG. 1 in particular, apparatus for conveying granular plastic resin material from the supply to receivers that retain and dispense the resin material when needed by a process machine is illustrated in FIG. 1. The apparatus, which is designated generally 88 in FIG. 1, preferably includes a vacuum pump designated generally 92 and shown schematically in FIG. 1. The vacuum pump preferably includes a vacuum pump suction head 93 also shown schematically in FIG. 1. Connected to the vacuum pump suction head 93 is an airflow regulator 30 shown only in schematic form in FIG. 1, but shown in various details in FIGS. 3 through 14. Airflow regulator 30 receives vacuum drawn by vacuum pump 92 through vacuum drawing conduit 100.
[0137] Vacuum drawing conduit 100 is connected to a plurality of receivers 16, each of which receives, retains and dispenses, as needed, granular plastic resin material to a machine, such as a gravimetric blender, or an extruder, or a molding press, as located preferably below a receiver 16. These machines are not illustrated in FIG. 1 to enhance the clarity of the drawing.
[0138] Further illustrated in FIG. 1 is a hopper 18 for storage of granular plastic resin material therein and a resin conveying conduit 98, which serves to draw resin from hopper 18 and to deliver the resin through resin conveying conduit 98 to the respective receivers as vacuum is drawn by the vacuum pump, with vacuum propagating through air flow regulator 30, vacuum drawing conduit 100, the various receivers 16, and resin conveying conduit 98, back to hopper 18.
[0139] FIG. 2 shows an alternate embodiment of a resin conveying system where this alternate embodiment of the conveying system has been designated 88A. FIG. 2, as in FIG. 1, depicts a vacuum pump 92 shown in schematic form having a vacuum pump suction head 93 also depicted in schematic form. In the alternate embodiment illustrated in FIG. 2, vacuum drawing conduit 100 leads directly into and communicates with vacuum pump suction head 93. In the embodiment illustrated in FIG. 2, an air flow regulator 30 is provided for each receiver 16, with the air flow regulator 30 for a respective receiver 16 being located in a portion of a connection conduit 102 that connects a respective receiver to vacuum drawing conduit 100. In FIG. 2, each air flow regulator 30 is depicted in a vertical orientation, just as is airflow regulator 30 depicted in a vertical orientation in FIG. 1. Each receiver is connected by connection conduit 102 to vacuum drawing conduit 100 with air flow regulator 30 forming a portion of connection conduit 102.
[0140] In FIG. 2, as in FIG. 1, a first conduit 98 serves to convey granular plastic resin from hopper 18 to the respective receivers in response to vacuum drawn by vacuum pump 92 as that vacuum propagates from vacuum pump 92 through second conduit 100, connection conduits 102, receivers 16, and resin conveying conduit 98 to hopper 18.
[0141] During operation of the resin conveying systems shown schematically in FIGS. 1 and 2, upon actuation of vacuum pump 92, vacuum is drawn at vacuum pump suction head 93. This vacuum, as it propagates back to hopper 18, serves to draw resin out of hopper 18 and into the respective receivers 16. In the embodiment illustrated in FIG. 2, individual air flow regulators 30 limit the suction or vacuum drawn by vacuum pump 92 through a given associated receiver 16. In the embodiment illustrated in FIG. 1, a single air flow regulator 30 limits the vacuum drawn through all receivers 16 forming a portion of the granular resin conveying system illustrated in FIG. 1.
[0142] Referring to FIGS. 1 and 2, the air flow regulator 30 portion of the resin delivery systems is preferably in the general form of a substantially vertically oriented tubular conduit, preferably having inlet and outlet ends 54, 56 respectively. The tubular character of air flow regulator 30 is apparent from FIGS. 3 through 14, where air flow regulator 30 preferably includes a vertically oriented exterior tubular conduit 32, with open-end caps 58, 60 defining and providing open inlet and outlet ends 54, 56 respectively. End caps 58, 60 are open, of generally cylindrical configuration, and are configured to fit closely about vertically oriented tubular conduit 32 so as to provide a substantially air tight fit between end caps 54, 56 and tubular conduit 32.
[0143] As illustrated in FIG. 5, air flow regulator 30 preferably includes, within vertically oriented exterior tubular conduit 32, a horizontally positioned plate 46, which is oriented perpendicularly to the axis of tubular conduit 32. Plate 46 is preferably configured as a circular disk of lesser diameter than the inner diameter of vertically oriented tubular conduit 32, with plate 46 further preferably including three legs extending outwardly from the circular interior disk portion of plate 46. Legs of plate 46 are designated 62 in FIG. 9, while the circular interior portion of plate 46 is designated 64 in FIG. 9. Plate 46 is secured to the interior of vertically oriented outer tubular conduit 32 by attachment of legs 62 to the interior surface of tubular conduit 32. Any suitable means of attachment, such as by welding, adhesive, mechanical screws, or end portion of legs 62 defining tabs fitting into slots within tubular conduit 32 as shown in FIG. 5, may be used.
[0144] As shown in FIGS. 5, 6, and 7, a baffle 52 is positioned within vertically oriented outer tubular conduit 32, below plate 46. Baffle 52 has a lower conical portion 66 and an upper cylindrical portion 44, with cylindrical portion 44 defining a fixed internal tubular segment of air flow regulator 30. Baffle 52 is preferably retained in position by a pair of screws designated 68, 70 respectively. Baffle 52 preferably rests on screw 68. Screw 70 preferably fits against the fixed internal tubular segment 44 portion of baffle 52 to secure baffle 52 in position within vertically oriented external tubular conduit 32. Lateral force applied by screw 70 in a direction perpendicular to the axis of vertically oriented external tubular conduit 32, with screw 70 in contact with fixed internal tubular segment 44, serves to effectively retain baffle 52 against movement within vertically oriented external tubular conduit 32.
[0145] The upper portion of baffle 52, defining fixed internal tubular segment 44, is adapted for sliding telescopic engagement with movable tubular segment 42. Fixed to movable tubular segment 42 is a first strut 48 preferably extending transversely across the upper portion of movable tubular segment 42 and preferably secured on either end to movable tubular segment 42, as illustrated in FIG. 10. Preferably extending downwardly from first strut 48 is a second strut 50, preferably secured to first strut 48 and preferably also to a sail 34, as illustrated in FIG. 10 and in FIGS. 5, 6, 7, 8, 9, 13 and 14.
[0146] Movable sail 34 is preferably planar and positioned fixedly on second strut 50 to remain perpendicular with respect to the axis of vertically oriented outer tubular conduit 32. Movable sail 34 is preferably of generally triangular configuration, as illustrated in FIGS. 9 and 10, with the sides of the triangle curving slightly inwardly. The curved edges 72 of movable sail 34 converge and terminate to form small rectangularly shaped extremities of sail 34, which are designated 76 in FIG. 9.
[0147] Movable sail 34 is positioned within generally vertically oriented outer tubular conduit 32 so that rectangular extremities 76 are closely adjacent to but do not contact the inner surface of vertically oriented outer tubular conduit 32, so long as sail 34 moves vertically up and down within vertically oriented external tubular conduit 32. The rectangular shape of extremities 76 with their outwardly facing planar surface assures minimal friction and consequent minimal resistance to movement of movable sail 34 in the event one of rectangular extremities 76 contacts the interior surface of vertically oriented tubular conduit 32, should sail 34 for some reason move laterally or otherwise and become skew to the vertical axis of tubular conduit 32.
[0148] Movable internal tubular segment 42 is telescopically movable, unitarily with sail 34, relative to and along fixed internal tubular segment 44. A lower limit of movement of movable tubular segment 42 is illustrated in FIG. 7, where the first strut portion 48 of movable tubular segment 42 (shown in FIG. 10) rests on the upper circular edge of fixed internal tubular segment 44. This is the condition when no air is flowing or drawn through the air flow regulator and gravity causes sail 34 together with movable internal tubular segment 42 to drop, with first strut 48 coming to rest on the upper circular edge of fixed tubular segment 44.
[0149] When air is flowing through air flow regulator 30, as illustrated generally in FIG. 6, the moving air pushes against movable sail 34, moving it upwardly. Movable internal tubular segment 42 moves upwardly unitarily with sail 34 due to the fixed connection of movable tubular segment 42 and movable sail 34 made via first and second struts 48, 50, as illustrated in FIGS. 5, 6, 7, 9, and 10.
[0150] If air flow upwardly through air flow regulator 30 reaches an extreme value, above an acceptable level of operation of the resin delivery system of which air flow regulator 30 is a part, the excessive force (resulting from the high volume of air flow contacting sail 34) pushes sail 34 upwardly to the point that upper annular edge 78 of movable internal tubular segment 42 contacts plate 46. In this condition, which is illustrated in FIG. 8, no air can pass between the upper annular edge 78 of movable tubular segment 42 and flow limiting horizontal plate 46, and air flow stops.
[0151] Once air flow stops through vertically oriented outer tubular conduit 32, gravity pulling downwardly on sail 34, connected movable internal tubular segment 42, and first and second struts 48, 50, causes these parts, which may be connected together and fabricated as a single integral assembly as shown in FIG. 8, to move downwardly, thereby again permitting air flow upwardly through air flow regulator 30 as depicted generally in FIG. 6. Consequently, air flow regulator 30 is self-regulating in that when air flow is too high, the force of air moving or impinging on sail 34 pushes movable internal tubular segment 42 upwardly until upper annular edge 78 of movable tubular segment 42 contacts plate 46 and no air can then escape upwardly between the upper annular edge 78 of movable tubular segment 42 and plate 46. This stops air flow through flow regulator 30 until downward movement of sail 34 together with movable internal tubular segment 42 moves upper annular edge 78 of movable tubular segment 42 away from plate 46, again permitting air to flow through the upper extremity of movable tubular segment 42, with air passing between upper annular edge 78 of movable internal tubular segment 42 and flow limiting horizontal plate 46, and then escaping through upper outlet end 56 of air flow regulator 30.
[0152] With the self-regulating characteristic of air flow regulator 30, the assembly consisting of movable internal tubular segment 42, first and second struts 48, 50 and sail 34 may oscillate somewhat about the position at which air flow drawn by suction is at the desired level, as the vacuum pump drawing air through flow regulator 30 varies in cubic feet per minute of air drawn.
[0153] Desirably, ends of first strut 48, which is depicted as being horizontally disposed in the drawings, are mounted in movable tubular segment 42 in movable fashion such that first strut 48 can move slightly, rotationally, relative to movable internal segment 42. This is to provide a small amount of play in the event movable sail 34 and second strut 50, which is vertically oriented and connected to movable sail 34, become skew with respect to the vertical axis of vertically oriented exterior tubular conduit 32. Should this occur, the movable characteristic of first strut 48, being slightly rotatable relative to movable internal tubular segment 42, effectively precludes movable internal tubular segment 42 from binding with respect to fixed internal tubular segment 44 and thereby being restricted from what would otherwise be freely telescoping movement of movable internal tubular segment 42 relative to fixed internal tubular segment 44.
[0154] Desirably first strut 48 is rotatable relative to movable internal tubular segment 42, to provide maximum freedom of vertical motion of movable internal tubular segment 42 in the event movable sail 34 becomes skew to the axis of vertically oriented exterior tubular conduit 32, with consequent frictional force restricting vertical movement of movable sail 34.
[0155] Baffle 52 preferably includes two portions, the upper portion preferably being defined by fixed internal tubular segment 44 and a lower portion preferably being defined by conical portion 66 of baffle 52. A lower edge of baffle 52 is circular and is designated 84 in the drawings. Circular edge 84 fits closely against the annular interior wall of vertically oriented exterior tubular conduit 32 so that all air passing upwardly through air flow regulator 30, namely through vertically oriented exterior tubular conduit 32, is constrained to flow through the interior of baffle 52. The tight fitting of the circular lower edge of baffle 52 against the interior wall of vertically oriented exterior tubular conduit 32 forces all air entering flow regulator 30 from the bottom to flow through the interior of baffle 52, flowing upwardly through lower conical portion 66 of baffle 52.
[0156] The air then flows further upwardly through the interior of fixed internal tubular segment 44. Thereafter, if movable internal tubular segment 42 is spaced away from flow limiting horizontal plate 46, air flows along the surface of movable internal tubular segment 42, passing the upper annular edge 78 of movable internal tubular segment 42; air then flows around the space between edge 82 of flow limiting horizontal plate 46 and the interior annular wall of vertically oriented exterior tubular conduit 32. The air then flows out of air flow regulator 30 via open outlet end 56 formed in end cap 60.
[0157] In an alternate embodiment of the air flow regulator, baffle 52 may be constructed from two pieces that fit closely together, with the two pieces being in facing contact in the area where they define fixed internal tubular segment 44, but diverging one from another in the area where they define conical portion 66 of baffle 52. As illustrated in FIG. 12, the two portions of baffle 52 are designated 66A and 66W where they diverge, with baffle portion 66A serving to channel air flow upwardly through vertically oriented exterior tubular conduit 32 into fixed internal tubular segment portion 44 of baffle 52. The space between the lower parts of baffle portions 66A and 66B is filled with a filler material 86 to provide additional assurance that all air entering vertically oriented exterior tubular conduit 32 from the bottom flows through fixed internal tubular segment 44 and on through movable internal tubular segment 42, and does not pass around the edge of baffle 52, namely between baffle 52 and the interior surface of vertically oriented exterior tubular conduit 32. Filler material 86 provides additional structural rigidity for flow regulator 30.
[0158] In another alternative environment of the air flow regulator, baffle 52 is one piece, preferably molded plastic, as illustrated in FIG. 11, where baffle 52 is designated 52B to distinguish it from the baffle construction illustrated in FIG. 12 and the baffle construction illustrated in the other drawing figures. In the baffle construction illustrated in FIG. 11, the one piece construction means that there is no need or space for any filler material.
[0159] The assembly illustrated in FIG. 10 comprising the moveable internal tubular segment 42, first strut 48, second strut 50 and moveable sail 34 may be constructed as a single piece or several pieces as required. The assembly of moveable internal segment 42, first and second struts, 48, 50 and moveable sail 34 is referred to as a sail assembly. It is not required that first and second struts 48, 50 be separate pieces; they may preferably be fabricated as a single piece. Additionally, second strut 50, which has been illustrated as a machine screw in FIGS. 9 and 10, need not be a machine screw. Any suitable structure can be used for second strut 50 and it is particularly desirable to fabricate first and second struts 48 and 50 from a single piece of plastic or metal, by molding, by machining, by welding, or by otherwise fastening two pieces together. Similarly with the hex nut, which is unnumbered in FIG. 10 and illustrated there, any other suitable means for attachment of the second strut or a vertical portion of a strut assembly to moveable sail 34 may be used.
[0160] Referring to FIGS. 13 and 14, an air flow regulator in accordance with the invention has been designated generally 30 and includes a vertically oriented exterior tubular conduit 32 and a moveable sail 34; these components are preferably the same as those described with respect to air flow regulator 30 above.
[0161] Air flow regulator 30 further includes a pair of concentric telescoping tubular segments 40, a moveable internal tubular segment 42, a fixed internal tubular segment 44, a flow limiting horizontal plate 46, first and second struts 48, 50, a baffle 52, and an inlet end 54 and an outlet end 56, all preferably the same as the air flow regulator illustrated in the other drawing figures and as described above. Other parts that are shown in FIGS. 13 and 14, and that appear to be identical to corresponding parts shown in FIGS. 3 through 12, are identical and are not further delineated herein for the sake of some brevity.
[0162] Air flow regulator 30 in accordance with the invention includes a pair of housings 110, 112 mounted on either side of vertically oriented exterior tubular conduit 32, where housing 110 is provided generally for an emitter 114, and housing 112 is provided generally for a detector 116. Any suitable emitter-detector combination can be used. Preferably emitter 114 emits an electromagnetic beam 118 and detector 116 detects beam 118 when beam 118 impinges on detector 116. Emitter 114 and detector 116 are mounted within housings 110, 112 at the positions illustrated in FIGS. 13 and 14. At this position, when emitter 114 emits an electromagnetic beam 118 and moveable internal tubular segment 42 is in contact with flow limiting horizontal plate 46, electromagnetic beam 118 is blocked by the cylindrical wall of tubular segment 42. Hence, detector 116 does not detect any electromagnetic beam and detector 116 sends a signal to an appropriate monitoring station or computer or other device indicating that the air flow regulator has blocked flow due to air flow through the air flow regulator exceeding the pre-selected design value.
[0163] When air is permitted to flow through the air flow regulator, due to moveable internal tubular segment being below and not contacting flow limiting horizontal plate 46, electromagnetic beam 118 from emitter 114 is detected by detector 116. (The beam is indicated as 118 in the drawing.) Detection of electromagnetic beam 118 by detector 116 indicates that either there is some permissible flow through the air flow regulator 30 or the entire resin delivery system has been shut down, meaning there is no air flow entering air flow regulator 30 at inlet end 54. However, the no air flow operation, or no air flow entering inlet end 54 is essentially of no interest, in that the air flow regulator of the invention, with the emitter-detector combination, is a self-limiting device as described above.
[0164] Air flow regulator 30 preferably contains no springs. Air flow regulator 30 preferably contains no sensors to provide operating feedback to a control device for regulation of air flow regulator 30. No feedback control sensors are needed since because flow regulator 30 is self-regulating and once in place, an air flow regulator is not subject to outside intervention or control. Air flow regulator 30 preferably includes a tubular valve, closing against a flat surface, where the tubular valve is defined by movable internal tubular segment 42 closing against flow limiting horizontal plate 46. Movable internal tubular segment 42 is in the form of an open-ended cylinder and is connected to a plate in the form of movable sail 34 to move movable tubular segment 42 against flow limiting horizontal plate 46. Air flow regulator 30 uses gravity alone to open the valve defined by the assembly of movable internal tubular segment 42, movable sail 34, and the connecting structure therebetween.
[0165] In the embodiment of the air flow regulator of this invention illustrated in FIGS. 15 and 16, there are effectively two design limits where design limit denotes the maximum air flow allowable through the air flow regulator. In this embodiment of the air flow regulator of the invention, a first design limit occurs when air flow through the air flow regulator is sufficient to move moveable sail 34 and hence moveable internal segment 42 upwardly to a position at which moveable internal tubular segment and the assembly of first and second struts 48, 50 contact piston 124 of solenoid 120, when piston 124 is extended from solenoid 120 and is at the position illustrated in FIG. 15. When the assembly of first and second struts 48, 50 moves slightly upwardly from the position illustrated in FIG. 15 and contacts the lower extremity of piston 124, when piston 124 is extended from solenoid 120 as illustrated in FIG. 16, this defines a second design limit. Air flow through air flow regulator 30, when the assembly of struts 48, 50 contacts the lower extremity of piston 124 when extended, is one of the two design limits. The second design limit occurs when the assembly of struts 48, 50 is just below and about to touch flow limiting plate 46. With air flow through flow the regulator with the struts 48, 50 at that position, air flow through regulator 30 is at a maximum. Once air flow increases even slightly, the air flow impinging sail 34 pushes assembly of struts 48, 50 and hence moveable tubular segment 42 upwardly against flow limiting plate 46, and flow through the flow regulator stops. Consequently, the air flow through regulator 30, when the upper extremity of moveable tubular segment 42 is just short of flow limiting plate defines the second design limit of air flow through regulator 30.
[0166] Regarding nomenclature, 30 denotes the regulator illustrated in FIGS. 1 through 12; 30 denotes the regulator illustrated in FIGS. 13 and 14; and 30 denotes the regulator illustrated in FIGS. 15 and 16. With the large number of common parts and operating characteristics common to these three regulators, sometimes the designators 30 and 30 etc. are used to refer to all of these regulators; the context makes clear as to when a specific characteristic is one of the regulators is the subject of the text.
[0167] As respecting the embodiment illustrated in FIGS. 15 and 16, when air flow is below the first design limit, regulator 30 remains fully open. The moment air flow equals the first design limit, the assembly of struts 48, 50 carrying moveable tubular segment 42 contacts the circular surface, unnumbered in the drawings, of piston 124 when piston 124 is in its extended position relative to solenoid 120. So long as piston 124 remains extended from solenoid 120, air flow through regulator 30. cannot exceed the first design limit. However, once solenoid 120 is de-actuated and piston 124 retracts into solenoid 120 to the position illustrated in FIG. 16, air flow through regulator 30. can increase up to the second design limit which, as noted above, occurs as moveable internal tubular segment 42 is approaching and in close proximity to flow limiting horizontal plate 46.
[0168] Apparatus for conveying granular plastic resin material from the supply to receivers that retain and dispense the resin material when needed by a process machine is illustrated in FIG. 1. The apparatus, which is designated generally 88 in FIG. 1, preferably includes a vacuum pump designated generally 92 and shown schematically in FIG. 1. The vacuum pump preferably includes a vacuum pump suction head 93 also shown schematically in FIG. 1. Connected to the vacuum pump suction head 93 is an airflow regulator 30 shown only in schematic form in FIG. 1, but shown in detail in various forms in FIGS. 3 through 16. Airflow regulator 30 receives vacuum drawn by vacuum pump 92 through vacuum drawing conduit 100.
[0169] Vacuum drawing conduit 100 is connected to a plurality of receivers 16, each of which receives, retains and dispenses, as needed, granular plastic resin material to a process machine, such as a granulator blender, or an extruder, or a molding press preferably located below a receiver 16. The process machines are not illustrated in FIG. 1 to enhance the clarity of the drawing.
[0170] Further illustrated in FIG. 1 is a hopper 18 for storage of granular plastic resin material therein and a resin conveying conduit 98, which serves to draw resin from hopper 18 and to deliver the resin through resin conveying conduit 98 to the respective receivers as vacuum is drawn by the vacuum pump, with vacuum propagating through air flow regulator 30, vacuum drawing conduit 100, the various receivers 16, and resin conveying conduit 98, back to hopper 18.
[0171] FIG. 2 shows an alternate embodiment of a resin conveying system designated 88A. FIG. 2, like FIG. 1, depicts a vacuum pump 92 shown in schematic form having a vacuum pump suction head 93 also depicted in schematic form. In the alternate embodiment illustrated in FIG. 2, vacuum drawing conduit 100 leads directly into and communicates with vacuum pump suction head 93. In the embodiment illustrated in FIG. 2, an air flow regulator 30 is provided for each receiver 16, with the air flow regulator 30 for a respective receiver 16 being located in a portion of a connection conduit 102 that connects a respective receiver to vacuum drawing conduit 100. In FIG. 2, each air flow regulator 30 is depicted in a vertical orientation, just as is airflow regulator 30 depicted in a vertical orientation in FIG. 1. Each receiver is connected by connection conduit 102 to vacuum drawing conduit 100 with air flow regulator 30 forming a portion of connection conduit 102.
[0172] In FIG. 2, as in FIG. 1, a first conduit 98 serves to convey granular plastic resin from hopper 18 to the respective receivers in response to vacuum drawn by vacuum pump 92 as that vacuum propagates from vacuum pump 92 through second conduit 100, connection conduits 102, receivers 16, and resin conveying conduit 98 to hopper 18.
[0173] During operation of the resin conveying systems shown schematically in FIGS. 1 and 2, upon actuation of vacuum pump 92, a vacuum is drawn at vacuum pump suction head 93. This vacuum, as it propagates back to hopper 18, serves to draw resin out of hopper 18 and into the respective receivers 16. In the embodiment illustrated in FIG. 2, individual air flow regulators 30 limit the suction or vacuum drawn by vacuum pump 92 through a given associated receiver 16. In the embodiment illustrated in FIG. 1, a single air flow regulator 30 limits the vacuum drawn through all of receivers 16 of the granular resin conveying system illustrated in FIG. 1.
[0174] In the air flow regulator illustrated in FIGS. 3 through 16, the movable internal tubular segment 42 is preferably made with a very thin wall, preferably from metal tubing, where the wall is preferably less than 1/32 inch in thickness.
[0175] The air flow regulator of the invention functions equally well with a vacuum pump drawing air through air flow regulator 30 from bottom to top by application of vacuum to outlet end 56 as depicted generally in FIGS. 1 and 2, or by air being supplied under positive pressure at inlet end 54 for passage upwardly through air flow regulator 30.
[0176] Although schematic implementations of present invention and at least some of its advantages are described in detail hereinabove, it should be understood that various changes, substitutions and alterations may be made to the apparatus and methods disclosed herein without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of this patent application is not intended to be limited to the particular implementations of apparatus and methods described in the specification, nor to any methods that may be described or inferentially understood by those skilled in the art to be present as described in this specification.
[0177] As one of skill in the art will readily appreciate from the disclosure of the invention as set forth hereinabove, apparatus, methods, and steps presently existing or later developed, which perform substantially the same function or achieve substantially the same result as the corresponding embodiments described and disclosed hereinabove, may be utilized according to the description of the invention and the claims appended hereto. Accordingly, the appended claims are intended to include within their scope such apparatus, methods, and processes that provide the same result or which are, as a matter of law, embraced by the doctrine of the equivalents respecting the claims of this application.
[0178] As respecting the claims appended hereto, the term comprising means including but not limited to, whereas the term consisting of means having only and no more, and the term consisting essentially of means having only and no more except for minor additions which would be known to one of skill in the art as possibly needed for operation of the invention.
