Valve system with improved sealing

Abstract

A valve system (1) includes a valve body (20) and a stuffing box (30) assembled to the valve body (20). The valve body (20) has an inner surface (29) defining an annular groove (21). The annular groove (21) includes an upper side (22), a lower side (23), and a bottom (24) extending axially between the upper side (23) and the lower side (23). The annular groove (21) together with the stuffing box (30) forms an annular cavity (80) for receiving a sealing element (15).

Description

Technical Field

[0001] The present invention relates to valve systems, and more particularly, but not exclusively, to pressure-actuated fluid valve systems. Background Technology

[0002] As shown in Figure 1A, a commonly used valve system includes a valve body 20 that houses a plunger 40, one end of which is fixed to a reciprocating valve stem 50. The valve stem 50 extends at its other end into a top box (not shown) of the valve system. The top box may include an actuator for controlling the reciprocating motion of the valve stem 50.

[0003] The valve system also includes a stuffing box 30, which is fixed to the valve body 20 and houses annular packing 60 for sealing the valve stem 50.

[0004] In the currently known systems, after the stuffing box 30 is threadedly connected to the valve body 20, a visible protrusion P is formed on the outer surface of the valve body 20. Dirt and the like may accumulate at this protrusion P, which is undesirable considering the general requirements of some industries such as the food and hygiene industries.

[0005] Furthermore, in known products, a sealing element 15 (typically made of polytetrafluoroethylene (PTFE)) for preventing liquid leakage between the stuffing box and the valve body is received in an annular cavity 80 formed between the stuffing box and the valve body, as shown in Figure 1B.

[0006] In this configuration, the sealing element 15 is compressed substantially axially by the stuffing box 30. Due to the large contact area between the sealing element 15 and the stuffing box 30, this configuration requires a relatively high tightening torque to compress the sealing element 15. Furthermore, since the sealing element 15 is rarely or never compressed radially, fluid 87 is not prevented from entering the space between the sealing element 15 and the stuffing box 30 on the radially inner side of the sealing element 15, as shown. Therefore, the pressure of the fluid 87 may, under certain circumstances, cause the sealing element 15 to flow into the axial gap 84 between the valve body 20 and the stuffing box 30. This stress release of the sealing element due to such deformation can lead to the possibility of leakage over time. Seal loosening can also cause loosening of the threads between the stuffing box 30 and the valve body 20.

[0007] DE4042035 discloses a sealing device on a valve spindle. The device includes a stuffing box disposed between a collar threaded thereon and a flange of the valve body. The stuffing box includes recesses that form cavities with the flange and collar, respectively, for receiving a sealing element. In DE 4042035, due to the large contact area between the sealing element and the stuffing box, the cavities also require relatively high tightening torque to compress the sealing element.

[0008] The existing valve system needs further improvement, and at least partially to make up for the above-mentioned shortcomings. Summary of the Invention

[0009] An exemplary embodiment of the present invention relates to a valve system including a valve body and a stuffing box assembled to the valve body. The valve body has an inner surface defining an annular groove having an upper side, a lower side, and a bottom extending axially between the upper and lower sides. The annular groove, together with the stuffing box, forms an annular cavity for receiving a sealing element.

[0010] The terms “upper” and “lower” refer to the relative positions along the longitudinal axis of the vertically oriented system, with the stuffing box located above the valve body.

[0011] In this invention, the sealing element is at least partially received in the groove. Therefore, the portion of the sealing element received in the groove is not axially compressed by the stuffing box. Consequently, due to the reduced contact area between the stuffing box and the sealing element, the assembly requires a lower tightening torque for sealing. In this way, it is easier to radially expand the sealing element against the stuffing box and valve body, forming the corresponding sealing surface. Fluid flow at the interface between the sealing element and the stuffing box, and along the entire height of the sealing element, can be more easily avoided.

[0012] The depth of the groove can be at least 1 mm.

[0013] The shoulder on the lower side of the limiting groove on the inner surface of the valve body can abut axially with the stuffing box.

[0014] The stuffing box preferably includes a first shoulder and a second shoulder.

[0015] The first shoulder can be configured to make axial contact with the sealing element.

[0016] The second shoulder can axially abut against the shoulder on the lower side of the limiting groove of the valve body.

[0017] The stuffing box may include a preferably cylindrical surface that extends axially between a first shoulder and a second shoulder and is configured to make radial contact with the sealing element.

[0018] Preferably, the valve system includes a plunger housed in a valve body; the plunger may be fixed at one end to a reciprocating valve stem.

[0019] The valve may include a first interface extending axially between the valve body and the stuffing box, the first interface being located axially further away from the plunger than the annular groove. The first interface may be located at a distance from the longitudinal axis of the system, a distance less than the distance between the bottom of the groove and the axis, but preferably greater than the distance between the axially extending surface between the first shoulder and the second shoulder and the axis.

[0020] The valve may include a second interface extending axially between the valve body and the stuffing box, the second interface being located axially closer to the plunger than the annular groove. The second interface may be located at a distance from the longitudinal axis of the system, a distance smaller than the distance between the axially extending surface between the first shoulder and the second shoulder and the axis.

[0021] The stuffing box is preferably assembled to the valve body by screwing, and the valve system includes corresponding threads on the stuffing box and the valve body. When viewed along the longitudinal axis of the valve system, the annular cavity is preferably located closer to the plunger than the threads. Therefore, the sealing element prevents fluid from flowing into the threads.

[0022] Sealing elements may include or be made of PTFE.

[0023] The valve system can be a pressure-actuated valve system or a motor-actuated valve system.

[0024] Exemplary embodiments of the present invention also relate to a method for assembling a valve body and a stuffing box for a valve system, the stuffing box including a collar that contacts the top surface of the valve body, the method comprising deforming the stuffing box during assembly of the stuffing box to the valve body, preferably by screwing the stuffing box to reduce the height of the collar protrusion after assembly.

[0025] By deforming the collar during assembly, the present invention allows for a smoother surface to be formed at the joint line between the stuffing box and the valve body without leaving any substantial stagnation area at the joint line.

[0026] In particular, the valve system thus obtained may not include any acute or right angles between the top surface of the valve body and the top surface of the collar.

[0027] Exemplary embodiments of the present invention also relate to a method for assembling a valve body and a stuffing box for a valve system, the valve body being screwed onto the stuffing box, the valve body having an inner surface defining an annular groove having an upper side, a lower side, and a bottom extending axially between the upper and lower sides, the annular groove and the stuffing box together forming an annular cavity for receiving a sealing element, the stuffing box including a collar contacting the top surface of the valve body, the method comprising deforming the stuffing box during assembly to the valve body, thereby reducing the height of the collar protrusion after assembly.

[0028] The assembled valve system can exhibit all or some of the characteristics of the valve system described above.

[0029] The method may include a first step of positioning the collar of the stuffing box on the top surface of the valve body while maintaining an axial clearance between the underside of the annular groove and the stuffing box, particularly between the underside of the annular groove and the second shoulder of the stuffing box.

[0030] The method may include a second step: mechanically deforming the collar of the stuffing box, particularly due to twisting during assembly, until the lower side of the annular groove contacts the stuffing box, particularly until the shoulder of the valve body defining the lower side of the annular groove contacts the second shoulder.

[0031] Exemplary embodiments of the present invention also relate to a valve system including a valve body and a stuffing box assembled to the valve body by screwing, the stuffing box including a collar in contact with the top surface of the valve body, the collar of the stuffing box deforming during the assembly of the stuffing box to the valve body.

[0032] Embodiments of the invention will now be described in further detail with reference to the accompanying drawings. These embodiments are merely illustrative and are not intended to limit the scope of the invention. Attached Figure Description

[0033] - Figure 1A (already described) is a schematic longitudinal cross-section of a known valve system;

[0034] - Figure 1B (already described) is an enlarged view of the opening groove sealing structure;

[0035] - Figure 2 This is a schematic diagram of the valve system of the present invention;

[0036] - Figure 3 This is a partial view of the valve system of the present invention;

[0037] - Figure 4 and Figure 5 yes Figure 3 Enlarged view of the central circle areas IV and V;

[0038] - Figure 5A and Figure 5B They are Figure 5 Separate views of the valve body and stuffing box;

[0039] - Figure 6 yes Figure 3 A partial view of the valve system at the start of assembly;

[0040] - Figure 7 and Figure 8 yes Figure 6 Enlarged view of the circled areas VII and VIII in the image. Detailed Implementation

[0041] like Figure 2As shown, the valve system 1 of the present invention includes a valve body 20 and a top box 10. The valve body 20 houses a plunger 40, one end of which is fixed to a reciprocating valve stem 50. The other end of the reciprocating valve stem 50 extends into the top box 10, which includes an actuator for controlling the up-and-down movement of the valve stem 50 along the longitudinal axis X of the system, thereby controlling the opening and closing of the valve via the plunger 40.

[0042] like Figure 3 As shown, the stuffing box 30 is screwed onto the valve body 20 via mating threads 16, which are located on the inner surface 29 of the valve body 20 and the outer surface 39 of the stuffing box 30. The stuffing box 30 includes a central hole 51, within which the valve stem 50 can slide.

[0043] like Figure 4 As can be seen, the top surface 38 of the collar 37 forms a smooth mating line 8 with the adjacent top surface 28 of the valve body 20, and there are no substantially acute or right-angled external protrusions between the top surfaces 28 and 38. In this way, no substantial stagnant area is formed at the mating line 8, which helps to prevent unwanted substances from accumulating therein.

[0044] like Figure 5 and Figure 5A As shown, the valve body 20 includes an annular groove 21 on its inner surface 29. The annular groove 21 includes a bottom 24, an upper side 22, and a lower side 23. The bottom 24 of the annular groove 21 extends axially between the upper side 22 and the lower side 23. The lower side 23 is defined by a shoulder 98 of the valve body.

[0045] The annular groove 21 preferably has a depth d measured in a direction parallel to the radial direction of the valve system, the depth d being at least 1 mm.

[0046] The annular groove 21 has a height h measured in a direction parallel to the longitudinal axis X of the valve system, which is preferably between 2 mm and 5 mm.

[0047] When measured radially, the width w1 of the shoulder 98 is preferably between 2 mm and 10 mm.

[0048] like Figure 5 and Figure 5B As shown, the stuffing box 30 includes a first shoulder 45 and a second shoulder 46 on its outer surface 39. The first shoulder 45 is configured to axially contact the sealing element 15. The second shoulder 46 axially abuts against the shoulder 98 of the lower side 23 defining the groove 21.

[0049] The first shoulder and the second shoulder are separated by an axially extending cylindrical surface 34.

[0050] The width w2 of the first shoulder section 45 can be between 2mm and 10mm.

[0051] The width w3 of the second shoulder 46 can be between 2mm and 10mm.

[0052] In the illustrated embodiment, when viewed in the longitudinal direction X of the valve system, the annular cavity 80 is located closer to the plunger 40 than the thread 16.

[0053] The valve system includes a first interface 84 between the stuffing box 30 and the valve body 20, which is located further from the plunger 40 than the annular cavity 80. For example... Figure 5 As can be seen, the first interface 84 is located radially inside the bottom 24 of the groove 21.

[0054] The valve system includes a second interface 83 between the stuffing box 30 and the valve body 20, which is located axially closer to the plunger 40 than the annular cavity 80. The second interface 83 is radially inward of surface 34.

[0055] To assemble the valve system, screw the packing box 30 into the valve body until the collar 27 abuts against the top surface 28 of the valve body 20, as follows. Figure 6 and Figure 7 As shown. Figure 8 As shown in detail, there is an axial gap 99 with a height of h' between the lower side 23 of the groove 21 and the shoulder 46.

[0056] Then, by further screwing the packing box 30 into the valve body 20, the collar 37 is mechanically deformed, thereby forming... Figure 4 The structure shown.

[0057] During this plastic deformation of the collar, the height h of the collar 37 protruding from the top surface 28 decreases, essentially to a value less than 1 mm. In this way, there is no noticeable discontinuity between the top surface 28 of the valve body 20 and the top surface 38 of the collar 37, which helps to avoid unwanted material buildup in the area around the joint line 8.

[0058] At the end of the turning, the shoulder 98 of the valve body abuts against the second shoulder 46 of the packing box 20, thereby axially compressing and radially expanding the sealing element 15 by the first shoulder 45 and the shoulder 98.

[0059] Therefore, four sealing interfaces are formed respectively between the sealing element 15 and the bottom 24, between the sealing element 15 and the lower side 23, between the sealing element 15 and the cylindrical surface 34, and between the sealing element 15 and the first shoulder 45.

[0060] The stuffing box 30 will not axially compress the sealing element 15 on the portion of the sealing element 15 that is received in the annular groove 21.

[0061] like Figure 5As shown, after assembly, the first shoulder 45 is closer to the lower side 23 in the axial direction than the upper side 22 of the annular groove 21.

[0062] The ratio l / h between the distance l from the first shoulder 45 to the lower side 23 and the height h of the annular groove 21 is preferably between 0.5 and 0.9.

[0063] The ratio between the depth d of the groove 21 and the width w2 of the first shoulder 45, i.e., d / w2, is preferably at least 2.

[0064] This invention is not limited to any specific set-top box, and various modifications can be made to the set-top box without departing from the scope of this invention.

Claims

1. A valve system (1) comprising a valve body (20) and a stuffing box (30) assembled to the valve body (20), the valve body (20) having an inner surface (29) defining an annular groove (21) including an upper side (22), a lower side (23), and a bottom (24) extending axially between the upper side (22) and the lower side (23), the annular groove (21) together with the stuffing box (30) forming an annular cavity (80) for receiving a sealing element (15), the stuffing box (30) including a first shoulder (45) and a second shoulder (46), the first shoulder (45) being in axial contact with the sealing element (15).

2. The valve system according to claim 1, wherein, The depth of the annular groove (21) d (At least 1mm) 3. The valve system according to claim 1, wherein, The shoulder (98) of the valve body (20) defining the lower side (23) of the annular groove (21) abuts axially with the stuffing box (30).

4. The valve system according to claim 3, wherein, The second shoulder (46) axially abuts against the shoulder (98) that defines the lower side (23) of the annular groove (21).

5. The valve system according to claim 1, wherein, The valve body (20) includes a cylindrical surface (34) that extends axially between the first shoulder (45) and the second shoulder (46) and is in radial contact with the sealing element (15).

6. The valve system according to claim 1, wherein, The valve body (20) houses a plunger (40) fixed at one end to a reciprocating valve stem (50).

7. The valve system according to claim 6, wherein, The stuffing box (30) is screwed onto the valve body (20), and the valve system includes corresponding threads (16) on the stuffing box (30) and the valve body (20), in the longitudinal direction (X) of the valve system, the annular cavity (80) is closer to the plunger (40) than the threads (16).

8. The valve system according to claim 6, comprising a first interface (84) extending axially between the valve body (20) and the stuffing box (30), and located axially further away from the plunger (40) than the annular cavity (80), and located at a distance (d1) from the longitudinal axis (X) of the system, the distance (d1) being less than the distance (d2) between the bottom (24) of the annular groove (21) and the axis (X).

9. The valve system according to claim 6, comprising a second interface (83) extending axially between the valve body (20) and the stuffing box (30), the second interface (83) being located axially closer to the plunger (40) than the annular cavity and at a distance (d4) from the longitudinal axis of the system, the distance (d4) being less than the distance (d3) between the cylindrical surface (34) of the valve body (20) extending axially between the first shoulder (45) and the second shoulder (46) and the axis (X).

10. The valve system according to claim 1, wherein the stuffing box (30) is screwed onto the valve body (20), the stuffing box (30) including a collar (37) in contact with the top surface (28) of the valve body (20), wherein the collar (37) of the stuffing box (30) is deformed during assembly of the stuffing box (30) onto the valve body (20), thereby reducing the height (h) of the collar (37) after assembly.

11. A method for assembling a valve body (20) and a stuffing box (30) of a valve system (1) according to claim 1, the stuffing box (30) comprising a collar (37) in contact with a top surface (28) of the valve body (20), the method comprising deforming the stuffing box (30) by screwing during assembly of the stuffing box (30) to the valve body (20), thereby reducing the height (h) of the protrusion of the collar (37) after assembly.

12. The method according to claim 11, comprising the first step of: placing the stuffing box (30) in contact with the top surface (28) of the valve body (20) while maintaining a gap (99) between the lower side (23) of the annular groove (21) and the stuffing box (30).

13. The method of claim 12, comprising the second step of: mechanically deforming the collar (37) of the stuffing box (30) due to the twisting torque during the assembly, thereby defining the shoulder (98) of the lower side (23) of the annular groove (21) into contact with the stuffing box (30).

14. The method according to claim 13, wherein, The gap (99) is axially formed between the lower side (23) of the annular groove (21) and the second shoulder (46).

15. The method according to claim 14, wherein, The second step includes mechanically deforming the collar (37) of the stuffing box (30) so that the lower side (23) of the annular groove (21) contacts the second shoulder (46).

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