Valve system for ATEX environments

Abstract

A valve system (1) including a valve having a valve stem (50), a valve body (20), and a stuffing box (30) assembled to the valve body, the valve system including a gasket (60) in contact with the valve stem (50) and the stuffing box (30), the gasket (60) including an electrically conductive material.

Description

Technical Field

[0001] This invention relates to valve systems, and particularly to valve systems for use in ATEX environments. Background Technology

[0002] ATEX is an abbreviation for "Atmosphere Explosible," referring to European Directive 2014 / 34 / EC. This directive regulates the placement of explosion-proof electrical and mechanical equipment, components, and protective systems on the market. One aspect of the ATEX directive requires that appropriate measures, such as proper grounding of the equipment, be taken to prevent electrostatic discharges that could trigger a dangerous explosion.

[0003] Existing valve systems typically include a plunger fixed at one end to a reciprocating valve stem. The plunger includes a PTFE disc seal configured to contact the valve body when the valve is closed. The valve stem extends at the other end into a top box within the valve system. The top box typically houses a piston and spring for controlling the reciprocating motion of the valve stem. The valve typically includes a plastic piston and / or piston washer that contact a plastic stop at the other end.

[0004] Because of the non-conductive components at the top and bottom, if charge or energy is generated due to the impact of the plunger on its seat, there is no ground continuity available to discharge the charge to the ground.

[0005] WO2015072472 discloses a valve with antistatic function, which includes a conductive thin corrugated plate member installed in an annular mounting groove, the annular mounting groove being disposed in the axial mounting portion of the valve body and / or valve stem, and the plate member contacting the outer peripheral surface of the valve stem and the inner peripheral surface of the axial mounting portion.

[0006] WO2005 / 002292 discloses an electrical grounding assembly for a control valve, the control valve including a valve body and valve internals electrically isolated from the valve body. The electrical grounding assembly includes a resilient grounding connector having a combination of a resilient region and a conductive surface compressed between the valve body and the valve internals to form and maintain internal electrical contact between the valve body and the valve internals.

[0007] The existing valve system needs further improvement, and at least partially to make up for the above-mentioned shortcomings. Summary of the Invention

[0008] An exemplary embodiment of the present invention relates to a valve system including a valve having a valve stem, a valve body, and a stuffing box assembled to the valve body. The valve system includes a gasket in contact with the valve stem and the stuffing box, the gasket comprising a conductive material.

[0009] Gaskets ensure grounding and electrical continuity between the moving valve stem and the stuffing box.

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

[0011] The gasket preferably comprises an annular portion and at least one flexible leg extending axially from the annular portion. The flexibility of the leg ensures positive contact with the sliding valve stem throughout its service life without adding too much friction to its movement.

[0012] Preferably, one or more flexible legs extend axially from the inner circumference of the annular portion. The washer may include multiple flexible legs, such as four legs equidistantly arranged on the inner circumference of the annular portion.

[0013] The flexible leg can contact the valve stem. The flexible leg may have a raised edge at its free end. Preferably, this raised edge does not contact the valve stem. Preferably, the flexible leg contacts the valve stem at the contact point. This limits friction between the valve stem and the washer.

[0014] The annular portion may contact the stuffing box. The stuffing box may include a stuffing box body that houses the stuffing box spring. The inner surface of the stuffing box may include a shoulder. The annular portion may be disposed between the shoulder and the stuffing box spring.

[0015] The packing box preferably comprises a conductive material, and the annular portion preferably contacts the packing box body, which is preferably made of metal.

[0016] The annular portion and the flexible leg are preferably integrally formed. The gasket may comprise bronze or other conductive alloys, or be made of bronze or other conductive alloys, such as brass or copper-beryllium alloys.

[0017] The stuffing box can accommodate a stuffing box spring, which is used to apply an axial force to at least one seal to cause its radial expansion to ensure a seal. An annular portion can be at least partially sandwiched between the inner surface of the stuffing box and the stuffing box spring. This allows electrical contact to be maintained between the gasket and the stuffing box.

[0018] Preferably, the flexible outrigger does not come into contact with the spring.

[0019] The inner diameter of the annular portion can be larger than the diameter of the portion of the valve stem received in the stuffing box. The gasket can have a constant thickness.

[0020] Preferably, the valve is a pressure-operated valve. In a variation, the valve is a solenoid valve.

[0021] The valve stem may include a conductive material and is preferably made of metal (e.g., stainless steel).

[0022] The valve system may include a plastic stop at the first end of the valve stem and a valve disc made of plastic material, such as a PTFE valve disc, connected to the second end of the valve stem. This valve disc seals the valve body when the valve system is closed.

[0023] The valve system may include a top box housing a plastic piston, with a valve stem extending through and attached to the piston. For example, a first end of the valve stem extends into the top box. The piston defines an upper chamber and a lower chamber within the top box. The upper chamber may house a spring configured to apply a downward force to the piston. The top box may include a liquid or gas inlet / outlet, allowing pressurization or depressurization of the respective upper and lower chambers. Pressurization of the lower chamber biases the spring, causing the piston and valve stem to move upward in a fixed relationship with the piston.

[0024] The outer surface of the valve stem may define a shoulder, and the valve system may include a plastic gasket disposed between the shoulder and the bottom of the piston, which helps to prevent fluid leakage between the upper and lower chambers of the top box.

[0025] Exemplary embodiments of the present invention also relate to a method for grounding the valve system of the present invention, wherein the valve stem is grounded only through a washer.

[0026] Exemplary embodiments of the present invention also relate to a method for manufacturing a valve system suitable for ATEX environments, comprising arranging conductive washers around a valve stem to obtain the valve system of the present invention.

[0027] 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

[0028] - Figure 1 This is a schematic longitudinal cross-sectional view of the valve system according to the present invention;

[0029] - Figure 2 yes Figure 1 Enlarged view of area II in the middle circle;

[0030] - Figure 3 A perspective view of an example gasket according to the invention; and

[0031] - Figure 4 It is an image showing a longitudinal cross-sectional view of a gasket parallel to the longitudinal axis of the valve system. Detailed Implementation

[0032] like Figure 1As shown, the valve system 1 of the present invention includes a valve body 20 and a top box 10, the top box 10 housing a plastic piston 14. A valve stem 50, made of a conductive material (e.g., stainless steel), extends through and is fixed to the piston 14. The valve stem is received in a plastic stop 79 at a first end and extends into the valve body 20 through a second end. The valve system includes a plunger 40, which includes a PTFE valve disc 80 connected to the second end of the valve stem 50. The valve disc 80 seals the valve body 20 in the closed state of the valve system.

[0033] The valve stem 50 includes a shoulder 56 on its outer surface. A plastic washer 41 is disposed between the shoulder 56 and the bottom of the piston 14.

[0034] The valve system in the illustrated embodiment is a pressure-operated valve and includes two fluid inlets / outlets 44 in the top housing 10. The stuffing box includes a stuffing box body 31 that houses a spring 70 and herringbone packing 35 actuated by the stuffing box spring 70. The inner surface of the stuffing box body defines a shoulder 34 facing the spring 70. The stuffing box body 31 is made of a conductive material and, for example, stainless steel.

[0035] like Figure 2 As shown, valve system 1 also includes a gasket 60 that contacts both valve stem 50 and stuffing box 30. Gasket 60 is made of a conductive material, such as brass, bronze, or a copper-beryllium alloy.

[0036] like Figure 3 As shown, the gasket 60 includes an annular portion 61 and four flexible legs 63 extending axially from the inner periphery 62 of the annular portion 62. The flexible legs 63 are regularly arranged around the longitudinal axis X of the valve system.

[0037] like Figure 2 As shown, the annular portion 61 is disposed between the axial end of the spring 70 and the shoulder 34 of the stuffing box body 31. The annular portion 61 is at least partially in contact with the shoulder 34. A flexible support leg 63 is disposed between the valve stem 50 and the spring 70.

[0038] The flexible outrigger 63 bends radially inward, as... Figure 4 As shown. The flexible leg has a raised edge 64 that does not contact the valve stem 50. The flexible leg 63 contacts the valve stem 50, for example, only through a contact point.

[0039] The diameter r of the inner circumference 62 of the annular portion 61 is greater than the diameter of the portion of the valve stem 50 that is received in the stuffing box 30.

[0040] The width w of the flexible outrigger can be between 2mm and 5mm.

[0041] The length l of the flexible outrigger can be between 5mm and 15mm.

[0042] The gasket can be produced, for example, by stamping a sheet of metal to form a metal block comprising an annular portion and a portion extending radially from the inner circumference of the annular portion before bending. This radially extending portion can be bent from a flexible support leg. The radially extending portion can be bent at an angle of 60° to 80° to ensure contact with the valve stem 50.

[0043] The orientation of the flexible support leg 63 ensures contact with the valve stem 50 while reducing friction between the flexible support leg 63 and the valve stem 50.

[0044] 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.

[0045] The number of flexible outriggers 63 does not have to be four.

Claims

1. A valve system (1) including a valve having a valve stem (50), a valve body (20), and a stuffing box (30) assembled to the valve body, the valve system including a gasket (60) in contact with the valve stem (50) and the stuffing box (30), the gasket (60) comprising a conductive material, the gasket (60) including an annular portion (61) and a plurality of flexible legs (63) extending axially from the annular portion (61), the flexible legs (63) extending axially from the inner periphery (62) of the annular portion (61).

2. The valve system according to claim 1, wherein, The plurality of flexible legs (63) are arranged at equal intervals on the inner periphery (62) of the annular portion (61).

3. The valve system according to claim 1, wherein, The washer (60) includes four flexible legs (63) arranged equidistantly on the inner periphery (62) of the annular portion (61).

4. The valve system according to claim 1, wherein, The annular portion (61) and the flexible support leg (63) are integrally formed.

5. The valve system according to claim 4, wherein, The annular portion (61) and the flexible leg (63) comprise bronze, brass, or a copper-beryllium alloy.

6. The valve system according to claim 1, wherein, The flexible support leg (63) contacts the valve stem (50), and the annular portion (61) contacts the stuffing box (30).

7. The valve system according to claim 1, wherein, The flexible leg (63) has a raised edge (64) that does not contact the valve stem.

8. The valve system according to claim 7, wherein, The flexible support leg (63) makes accurate contact with the valve stem (50).

9. The valve system according to claim 1, wherein, The stuffing box (30) includes a stuffing box body (31) that houses a stuffing box spring (70), and the annular portion (61) is at least partially sandwiched between the inner surface (39) of the stuffing box body (31) and the stuffing box spring (70).

10. The valve system according to claim 1, wherein, The diameter (r) of the inner circumference (62) of the annular portion (61) is greater than the diameter of the portion of the valve stem (50) received in the stuffing box (30).

11. The valve system according to claim 1, wherein, The valve stem (50) comprises a conductive material.

12. The valve system according to claim 1, comprising a plastic stop (79) at a first end of the valve stem (50) and a valve disc (80) of plastic material connected to a second end of the valve stem (50).

13. The valve system of claim 1, comprising a top box (10) housing a plastic piston (14), the valve stem (50) extending through the piston (14).

14. The valve system according to claim 13, wherein, The outer surface of the valve stem (50) defines a shoulder, and the valve system includes a plastic gasket (41) disposed between the shoulder and the bottom of the piston (14).

15. A method for grounding a valve system according to any one of claims 1 to 14, wherein, The valve stem (50) is grounded only through the washer (60).

16. A method for manufacturing a valve system suitable for ATEX environments, comprising arranging a conductive washer (60) around the valve stem (50) to obtain a valve system according to any one of claims 1 to 14.

17. Use of the valve system according to any one of claims 1 to 14 in an ATEX environment.

Images