Valve

Abstract

A valve including a valve housing through which a process medium can flow and in which a valve seat is located, which surrounds a through-flow opening and to which a valve member mounted on a spindle is assigned in such a way that the valve member can be moved by means of an actuating stroke of the spindle between a blocking position in which the valve member bears against the valve seat in a process medium-tight manner and an open position in which the valve member is raised off the valve seat, and wherein an interface for coupling a drive unit generating the actuating stroke of the spindle is provided on the valve housing, and wherein a sealing device through which the spindle passes is accommodated in the valve housing, the sealing device is accommodated in a seal cartridge which is separate from the valve housing and configured as an operational pre-assembly.

Claims

1. A valve comprising a valve housing through which a process medium can flow and in which a valve seat is located, which surrounds a through-flow opening and to which a valve member mounted on a spindle is assigned in such a way that the valve member is moved by means of an actuating stroke of the spindle between a blocking position in which the valve member bears against the valve seat in a process medium-tight manner and an open position in which the valve member is raised off the valve seat, and wherein an interface for coupling a drive unit generating the actuating stroke of the spindle is provided on the valve housing, and wherein a sealing device through which the spindle passes is accommodated in the valve housing, the sealing device comprising a spring and a seal assembly including sealing means bearing against the spindle while forming a seal and wherein the sealing device is accommodated in a seal cartridge which is separate from the valve housing and configured as an operational pre-assembly and which comprises a cartridge housing, which is secured to the valve housing, and in which the seal assembly and the spring are accommodated in such a way that the seal assembly is resiliently preloaded against the cartridge housing by the spring, and wherein the cartridge housing has a locating section comprising an encasing region and a base region, the encasing region encasing the seal assembly and the spring, and the base region provided with a central through-hole, and wherein the base region has an inner cone surface complementing a mating outer cone surface formed on the seal assembly, wherein the diameter of the through-hole is greater than the outer diameter of an end region of the seal assembly to such an extent that the seal assembly, owing to the mutually complementary cone surfaces and the preload generated by the spring, projects through the through-hole, terminating outside the encasing region with its free end.

2. A valve according to claim 1, wherein the seal cartridge has a mounting interface for self-retaining mounting on the valve housing, the mounting interface being formed on the cartridge housing.

3. A valve according to claim 2, wherein the mounting interface has a male thread formed on the outer surface of the cartridge housing.

4. A valve according to claim 3, wherein the cartridge housing has a cover section, which is connected to the locating section and has a through-opening for the spindle, and on which the mounting interface is formed, the cover section being cylindrical and the male thread for tightening into the valve housing being formed on a lateral surface of the cartridge housing.

5. A valve according to claim 4, wherein the cover section has a support surface, which faces the locating section and on which the spring is supported.

6. A valve according to claim 4, wherein the cover section and the locating section are welded to one another.

7. A valve according to claim 1, wherein the sealing device comprises a sealing unit, which is formed separately from the seal assembly and bears against the spindle while forming a seal, and which is positioned at an axial distance from the seal assembly, the sealing unit comprising at least one annular sealing element with at least one sealing lip bearing against the spindle to form a seal.

8. A valve according to claim 7, wherein the annular sealing element comprises at least two axially spaced sealing lips.

9. A valve according to claim 7, wherein the sealing unit is located in a cover section of the cartridge housing.

10. A valve according to claim 1, wherein the valve housing is constructed in several parts, with a fluid ducting part including the valve seat and a separately formed hollow-cylindrical interface part with the interface for coupling the drive unit.

11. A valve according to claim 10, wherein the interface part is releasably secured to the fluid ducting part.

12. A valve according to claim 11, wherein the releasable connection between the interface part and the fluid ducting part is implemented by way of a screw connection which comprises a male thread formed on the interface part and a female thread formed on a coupling section of the fluid ducting part.

13. A valve according to claim 10, wherein the seal cartridge is accommodated in the interface part and releasably secured there.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) A preferred embodiment of the invention is shown in the drawing and explained in greater detail below. In the drawing:

(2) FIG. 1 is a perspective view of a preferred embodiment of the valve according to the invention,

(3) FIG. 2 is a front view of the valve from FIG. 1,

(4) FIG. 3 is a longitudinal section through the valve along line from FIG. 2,

(5) FIG. 4 is an exploded view in longitudinal section of the components of the valve according to FIG. 3, and

(6) FIG. 5 is an enlargement of detail X from FIG. 4

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(7) FIGS. 1 to 5 show a preferred embodiment of the valve 11 according to the invention. The valve 11 is suitable for use as a process valve in the process industry.

(8) As FIGS. 1 and 3 show in particular, the valve 11 has a valve housing 12, in which a through-flow passage 15 extends between an inlet 13 and an outlet 14.

(9) If used in the food industry, the valve housing is preferably made of stainless steel. If aggressive substances such as acids are used as process medium, the valve housing is expediently made of a plastic material with a higher chemical resistance against such substances.

(10) In the through-flow passage 15, between the inlet 13 and the outlet 14, there is a through-flow orifice 16 surrounded by an annular valve seat 17. The valve seat 17 is expediently designed as an annulus. Theoretically, however, an oval form of the valve seat is conceivable as well.

(11) A valve member 18 located on a spindle 19 is assigned to the valve seat 17.

(12) Purely by way of example, the valve member 18 is shown as a multi-part unit, in this case comprising a disc 20 with a through-hole 21, through which an end section 22 of the spindle can be inserted. The disc is welded to the spindle, for example. The valve member 18 further includes a counterpart 23 with a blind hole-type locating opening 24, which is provided with a female thread 25. Complementary thereto, the end section 22 of the spindle 19 has a male thread 26, by means of which the counterpart 23 can be tightened onto the end section 22 of the spindle 19. Between the counterpart 23 and the disc 20, an annular seal ring 27 is clamped; this is expediently made of a plastic material, for example PTFE.

(13) By means of an actuating stroke of the spindle 19, the valve member 18 is movable between a blocking position, in which the valve member 18 bears against the valve seat with its seal ring 27 to form a seal, and an open position (FIG. 3), in which the valve member 18 is lifted off the valve seat 17. The actuating stroke of the spindle 19 is generated by a drive unit (not shown) which is coupled by way of an interface 28 formed on the valve housing 12. The drive unit may be a fluidic, in particular pneumatic, drive unit. In the latter case, the actuating stroke of the spindle 19 can, for example, be generated by an operating cylinder to which fluid pressure is applied. Alternatively, the drive unit could be designed as an electric drive unit.

(14) As FIG. 3 in particular shows, the valve housing 12 is constructed in several parts. The valve housing 12 has a fluid ducting part 29, in which the through-flow passage 15 and the valve seat 17 are formed. The valve housing 12 further has an interface part 30, where the interface 28 for coupling the drive unit is formed. The interface part 30 is designed as a hollow cylinder and has several functional sections. One of these is a cylindrical locating section 31 with a male thread 32 on its lateral surface. This male thread 32 corresponds to a female thread 34 formed on a locating stub 33 of the fluid ducting part 29, whereby the interface part 30 can be tightened onto the fluid ducting part 29. This makes the removal of the interface part 30 from the fluid ducting part 29 easy, for example for replacement by another interface part 30 with another interface 28. At smaller nominal widths, the interface part 30 and the fluid ducting part 29 can be designed as a single part, which may be made of a casting material, for example.

(15) On the outer lateral surface of the locating section 31, there is further provided a continuous annular groove into which a seal ring 35 is inserted and located there. This outer seal ring 35 provides the seal between the interface part 30 and the fluid ducting part 29.

(16) On the inner lateral surface of the locating section 31, there is provided a further annular groove into which a seal ring 37 is inserted and located there.

(17) A further functional section of the interface part 30 is an interface section 36, on which the interface 28 is formed. The interface section is integrally joined to the locating section 31 but has a larger diameter than the latter, so that the annular shoulder formed at the transition between the interface section 36 and the locating section 31 forms a stop which hits the locating stub 33 of the fluid ducting part 29, thereby predetermining the length of thread engagement of the interface part 30.

(18) The valve 11 further comprises a sealing device 38, through which the spindle 19 passes and which comprises a seal assembly 39 including sealing means preloaded by spring means and bearing against the spindle 19 while forming a seal.

(19) The sealing device 38 is accommodated in a seal cartridge 40, which is separate from the valve housing 12 and configured as an operational pre-assembly.

(20) As FIG. 5 in particular shows, the seal cartridge 40 comprises a cartridge housing 41, which can be or is secured to the valve housing 12 and in which the seal assembly 39 and the spring means are accommodated.

(21) The cartridge housing 41 has several functional sections. A locating section 42 is provided for the accommodation of the seal assembly 39 and the spring means. The locating section 42 has the shape of a beaker and comprises an encasing region 43 encasing the seal assembly 39 and the spring means and a base region 45 provided with a central through-hole 44.

(22) By way of example, the seal assembly is shown in the form of a V-sleeve packing, with a plurality of annular V-sleeves 46 stacked on top of one another in the axial direction being provided as individual sealing elements. As FIGS. 4 and 5 in particular show, the V-sleeves 46 are approximately V-shaped in cross-section and stacked in the manner of riders, so that the V-sleeves 46 widen radially under pressure, thereby providing a fluid-tight contact on the spindle 19. The contact pressure of the V-sleeves 46 is generated by the spring means referred to above, which comprise a compression spring 47 and provide a preload for the entire V-sleeve packing in a way to be explained in greater detail below.

(23) As FIG. 5 shows particularly clearly, the seal assembly 39 comprises a wiper 70 assigned to the base region and mounted there. The wiper 70 is likewise made of a plastic material, which may, however, be more rigid than that of the V-sleeves. The wiper 70 has a hollow-cylindrical base section 71, from the end faces of which an annular bearing ridge 73, on which the V-sleeves 46 placed above are mounted in the manner of riders, projects upwards. The base section 71 is adjoined in the axial direction by a lip section 72, which has on its outer circumference a cone surface 48 acting together with a cone surface 49 formed on the inside of the base region 45.

(24) A further functional section of the cartridge housing 41 is a cover section 50 having a through-opening 51 for the spindle. The cover section is provided with a mounting interface 52 to be explained in greater detail below. The cover section 50 is cylindrical and has an annular groove 53, which is concentric with the through-opening 51 and into which an end section of the encasing region 43 of the locating section 42 dips to be joined there to the cover section 50. The locating section 42, i.e. the encasing region 43, it expediently welded to the cover section 50. The annular end face of the cover section 50, which is formed between the annular groove 53 and the through-opening 51, forms a support surface 54 for the compression spring 47. The opposite end of the compression spring 47 is supported on a backing ring 55, which is movably mounted within the encasing region 43 and which may be designed as a washer, for example. The backing ring 55 is pressed onto the V-sleeve packing, so that this and the V-sleeves 46 are preloaded towards the base region 45. The contact pressure of the compression spring 47 induces a radial spreading of the V-sleeves 46 and an axial displacement of the V-sleeve packing. As the through-hole 44 in the base region 45 is larger than the outer diameter of the spindle 19, a part 74 of the lip section 72 of the wiper 70 can pass through the through-hole 44, so that it terminates a little outside the locating section as shown in FIG. 5. The protruding annular part 74 of the lip section 72 is therefore capable of wiping or scraping off any dirt, process medium or the like accumulated on the spindle 19.

(25) In the region of the through-opening 51, a bearing bush 60 is further secured in, for example pressed into, the cover section 50; this used for the bearing-mounting and the radial location of the axially movable spindle 19.

(26) In addition to the seal assembly 39, the sealing device 38 further comprises a sealing unit 56, which is formed separately from the seal assembly 39. The sealing unit 56 comprises at least one annular sealing element 57, which is secured in an annular bearing chamber 58 formed for this purpose in the cover section 50. The sealing element 57 consists of an elastomer material. In the illustrated embodiment, the sealing element 57 has two axially spaced sealing lips 59a, 59b, which bear against the outer circumference of the spindle 19 while providing a fluid-tight seal. In addition to the sealing function, the sealing lips 59a, 59b have a further function, each of them serving as a wiper, preventing the ingress of dirt from the environment into the process medium via the control medium.

(27) The seal cartridge 40 therefore provides a dual sealing action, i.e. a seal against the process medium and a seal against the control medium or the environment. The seal cartridge 40 further provides a dual wiper.

(28) In the assembly of the valve 11, which can be seen in FIG. 4, various modules are assembled quickly and easily. First, the spindle 19, which can be separated from the drive unit, is installed into the fluid ducting part 29 of the valve housing 12. The interface part 30 can then be screwed onto the fluid ducting part 29. Finally, the seal cartridge 40 can be screwed into the interface part 30. Alternatively, the seal cartridge 40 can be screwed into the interface part 30 before the interface part 30 is secured to the fluid ducting part 29. Lastly, the drive unit can be coupled by bolting a component of the drive unit provided for this purpose to the interface 28. The mounting of the drive unit on the interface 28 is independent of the seal cartridge 40. The seal cartridge is therefore not required for coupling the drive unit. This makes the dismantling of the valve 11, for example for replacing the seal cartridge 40, a very simple and quick operation as well, by uncoupling the drive from the interface 28 and unscrewing the seal cartridge 40 from the interface part 30.