Safety valve

Abstract

A safety valve has a valve seat (8) and a sealing body (12) movable relative to the valve seat (8) along a first axis (X), the sealing body being biased with a holding force (F.sub.H) along this first axis (X) in the direction of the valve seat (8). A sealing element (24) is arranged on the sealing body (12) in a manner such that with one first side (32) it can be brought into sealing contact with the valve seat (8). A pressure surface situated on a second side (34) of the sealing element (24), which is opposite to the first side (32), is connected via a pressure channel (40) to a pressure region (4) surrounded by the valve seat (8). The sealing body (12) has a contact surface (25) coming to bear on a rest surface (10) in the closed condition of the safety valve.

Claims

1. A safety valve comprising: a valve seat (8) surrounding a pressure region; a sealing body (12) movable relative to the valve seat (8) along a first axis (X), the sealing body being biased and having a holding force (F.sub.H) along the first axis (X) in a direction of the valve seat (8); a sealing element (24) arranged on the sealing body (12) and having a first side (32) to be brought into sealing contact with the valve seat (8) and a second side (34) opposite to the first side (32), and a pressure surface situated on the second side (34) of the sealing element (24) and connected via at least one pressure channel (40) to the pressure region; and a contact surface (25) arranged on the sealing body (12), the contact surface coming to bear on a rest surface (10) in a closed condition of the safety valve.

2. The safety valve according to claim 1, wherein the sealing body (12) comprises at least one contact element, on which the contact surface (25) is formed.

3. The safety valve according to claim 1, wherein the sealing element (24) is movable relative to the sealing body (12).

4. The safety valve according to claim 3, wherein the sealing element (24) is movable along the first axis (X).

5. The safety valve according to claim 4, wherein the sealing body (12) comprises a holding element (26) which encompasses the first side (32) of the sealing element (24).

6. The safety valve according to claim 1, wherein the pressure channel (40) is formed in at least one of the holding element (26) and the sealing element (24).

7. The safety valve according to claim 1, wherein sealing body (12) comprises a recess (18) open in the direction of the valve seat (8), the recess (18) being arranged in at least one of the sealing element (24) and the holding element (26).

8. The safety valve according to claim 1, wherein a pressure space (38) is formed between the pressure surface of the sealing element (24) and a first surface (36) of the sealing body (12) lying opposite the pressure surface, wherein the pressure space (38) is connected via the pressure channel (40) to the pressure region (4) within the valve seat (8).

9. The safety valve according to claim 1, wherein the pressure surface of the sealing element (24) in a direction transverse to the first axis (X) has a larger surface (A.sub.+) than a part-surface (A−) of the first side (32) of the sealing element (24), the part-surface being enclosed by the valve seat (8) in the closed condition of the safety valve.

10. The safety valve according to claim 1, wherein the rest surface (10) is formed within the valve seat (8).

11. The safety valve according to claim 1, wherein the rest surface (10) is formed outside the valve seat (8).

12. The safety valve according to claim 11, wherein the rest surface (10) peripherally surrounds the valve seat (8).

13. The safety valve according to claim 12, wherein the rest surface (10) is designed as one piece with the valve seat (8).

14. The safety valve according to claim 1, wherein an elastic seal (30, 30′) is arranged between the sealing element (24) and the sealing body (12) along an outer periphery of the pressure surface (A.sub.D).

15. The safety valve according to claim 14, wherein the sealing element (24, 24′) and the seal (30, 30′) are designed as one piece.

16. The safety valve according to claim 14, wherein the seal (30, 30′) is arranged in a groove (28) formed peripherally to the first axis (X) on an outer periphery of the sealing element (24).

17. The safety valve according to claim 14, wherein the seal (30, 30′) is arranged in a groove (28) formed peripherally to the first axis (X) on an inner periphery of the sealing body (12).

18. The safety valve according to claim 1, wherein the sealing element (24) comprises an elastic material.

19. The safety valve according to claim 1, wherein the sealing element (24) comprises a metallic material.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) The foregoing summary, as well as the following detailed description of the invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there are shown in the drawings embodiments which are presently preferred. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. In the drawings:

(2) FIG. 1 is a schematic, partial longitudinal section view of a safety valve according to an embodiment of the invention;

(3) FIG. 2 is an enlarged sectional view of the detail II of the safety valve according to FIG. 1;

(4) FIG. 3 is an enlarged sectional view of a further representation of the detail II from FIG. 1; and

(5) FIG. 4 is a longitudinal section of an alternative embodiment of a sealing body of the safety valve according to FIGS. 1 and 2.

DETAILED DESCRIPTION OF THE INVENTION

(6) A safety valve which is represented schematically in FIG. 1 comprises a valve body 2 which surrounds a pressure region 4 which leads a medium. A valve seat 8 which is radially symmetrical about a longitudinal axis X of the valve body 2 and formed on a face side 6 of the valve body 2 formed perpendicularly to the longitudinal axis X, extends in the form of an annular projection parallel to the longitudinal axis X about the pressure region 4. Unless described otherwise hereinafter, the longitudinal axis X is to be understood as the symmetry and movement axis of the subsequently described design of the safety valve. A rest surface 10 is formed transversely to the longitudinal axis X, laterally or radially outside the valve seat 8 on the face side 6 of the valve body 2.

(7) A disc-shaped sealing body 12 is arranged lying opposite the face side 6 of the valve body 2, along the longitudinal axis X. The sealing body 12 is biased by a holding force F.sub.H which acts along the longitudinal axis X in the direction of the valve body 2. A plunger 14, via which a pilot-controlled biasing of the sealing body 12 in the direction of the valve seat 2 is rendered possible, can be arranged at a side of the sealing body 12 which is away from the valve body 8, i.e., the biasing of the sealing body 12 is effected in a pressure-dependent manner. A spring preloading or spring biasing of the sealing body 12 in the direction of the valve seat 8 with the holding force F.sub.H can alternatively be envisaged.

(8) The sealing body 12 comprises an annulus-shaped recess 18, which faces the valve seat 8 and which at the outer periphery is delimited by a collar or edge 20 of the sealing body 12, the collar or edge extending to the face side 6, and is centrally delimited by a pin (stub) 22 of the sealing body 12, which extends in the direction of the longitudinal axis X to the face side 6. In the closed condition of the safety valve, a contact surface 25 formed by the face side of the edge 20 bears on the rest surface 10, i.e., the sealing body 12 is in contact with the valve body 2 via the holding force F.sub.H. The flow of force thereby does not run via the valve seat 8, but via the contact surface 25 and the rest surface 10.

(9) An annulus-shaped sealing element 24, as well as a holding element 26 which is likewise designed in an annulus-shaped manner, is arranged within the recess 18. Thereby, the holding element 26 is arranged peripherally surrounding the pin 22 and is held in the recess via a nut 48. The sealing element 24 bears on the edge 20 of the sealing body 12, at the inner periphery. The sealing element 24 in its outer periphery and peripherally of the longitudinal axis X comprises a groove 28, in which an O-ring 30 is arranged as an elastic seal, with which the sealing element 24 in the recess 18 bears on the inner periphery of the edge 20 in a pressure-tight manner.

(10) The sealing element 24 is preferably made of plastic, in particular of fluoropolymers. With this, it is designed in a resistant manner with regard to different fluids and/or gases. With regard to the application, it can be advantageous if the sealing element 24 has a certain elasticity, or however can withstand high pressures without thereby being deformed. The sealing element 24 can alternatively also be formed from metal or from a metal alloy.

(11) The holding element 26 is radially arranged in the recess 18 between the pin 22 and the sealing element 24, so that it annularly surrounds the pin. The holding element 26 is surrounded by the medium in the closed condition of the safety valve. The sealing element 24 in the closed condition of the safety valve, with a first side 32 facing the face side 6 of the valve body 2 bears on the valve seat 8 of the valve body 2 (FIG. 2). The sealing body 12 in the recess 18 has a first surface 36 which faces the valve seat 8 and which lies opposite a second side 34 of the sealing element 22. The second side 34 is thereby formed on the sealing element 24, away from the first side 32. A pressure space 38 is thereby formed in the inside of the recess 18, between the second side 34 of the sealing element 24 and the first surface 36 of the sealing body 12.

(12) The holding element 26 comprises a pressure channel 40, which extends parallel to the longitudinal axis X as a through-hole and connects the pressure region 4 in the inside of the valve seat 8 to the pressure space 38. This means that the medium is located in the pressure channel 40 and in the pressure space 38 and everywhere has the same pressure as it also has in the pressure region 4.

(13) The sealing element 24 on its inner periphery facing the holding element 26 comprises a slot or step extending transversely to the longitudinal axis X. The holding element 26 at its outer periphery comprises a catch (lug) element 42, which extends radially outward and which has a positive fit with the slot of the sealing element 24. The catch element 42 engages positively into the slot of the sealing element 24 in a manner such that the sealing element 24 is limited in its movement possibility relative to the sealing body 12 in the direction of the longitudinal axis X. The catch element 42 thereby comprises a catch surface 44, which is designed transversely to the longitudinal axis X on a side of the catch 42 which is away from the face side 6 of the valve body 2. This catch surface bears on the first side 32 of the sealing element 24 in the step at its inner periphery and thus encompasses the sealing element 24 from its first side 32. The holding element 26 is preferably arranged on the sealing body 12 in a manner such that the catch surface 44 has such a distance to the first surface 36 of the sealing body 12, that a certain play is formed along the longitudinal axis X between the sealing element 24 and the catch element 42, within which play the sealing element 24 can move axially relative to the sealing body 12.

(14) The holding element 26 thus with its catch element 42 limits the movability of the sealing element 24 along the longitudinal axis X in the direction of the valve body 2. A thread, on which a nut 48 is screwed, such that the nut 48 fastens the holding element 26 on the sealing body 12, is formed on the pin 22 of the sealing body 12 which extends in the direction of the valve body 2. Other suitable fasteners for fastening the holding element 22 on the sealing body 2 can also be arranged alternatively to the nut 48, wherein for this the pin 22 of the sealing body 12 can also have another suitably adapted design. The nut 48 or an alternative suitable fastener is designed in a manner such that the pressure channel 40 formed in the holding element 26 is not closed due to their arrangement, and thus the connection between the pressure region 4 of the valve body 2 and the pressure channel 40 as well as the pressure space 38 is not interrupted.

(15) In the closed condition of the safety valve, a force which is effected by the same pressure p of the medium which prevails on the first and second side 32, 34, acts in each case upon the sealing element 24 upon its first side 32 as well as upon its second side 34 (FIGS. 2, 3). Whereas the force on the first side 32 is directed away from the valve seat, the force on the second side 34 is directed in the direction of the safety valve seat. The forces thus act counter to one another. The active surface A− of the first side 32 is the annulus-shaped, pressure-impinged surface of the sealing element 24 transverse to the longitudinal axis X, the surface being enclosed by the valve seat 8 and surrounding the holding element. The active surface A− thereby has a radial annular width d−. The active surface A.sub.+ on the second side 34 of the sealing element 24 is the annulus-shaped, pressure-impinged surface which faces the sealing body 12 and the pressure space 38. The active surface A.sub.+ thereby has a radial annular width d.sub.+ (see FIG. 3). The sealing element is designed in a manner such that the active surface A.sub.+ is larger than the active surface A−, i.e., that with a pressure p of the medium, the sealing element 24 is pressed in the direction of the valve seat 8 with a resulting force F.sub.R≈p(A.sub.+ minus A−), and thus comes to bear on the valve seat 8 in a sealing manner.

(16) Forces which are caused by the pressure of the medium also still act on the sealing body 12 in the direction of the valve seat 2, apart from the holding force F.sub.H. The pressure p, in a manner directed away from the face side 6 of the valve body 2, acts upon the surface of the pin 22 and the first surface 36 of the sealing body 12 in the recess 18, thus upon the circular surface A.sub.D with the diameter d.sub.A of the recess 18, from which a force F.sub.D counteracting the holding force F.sub.H and the resulting force F.sub.R results.

(17) The recess 18 has a diameter d.sub.A so that with a limit pressure p.sub.g of the medium, the force F.sub.D which arises on the sealing body 12 by way of the medium and which is directed away from the valve seat 8 is larger than the sum of the holding force F.sub.H and the resulting force F.sub.R. Thus, the sealing body 12 is brought out of contact with the rest surface 10 departing from the limit pressure p.sub.g. If the axial travel of the sealing body 12 is larger than the axial play of the sealing element 24, the sealing element 24, due to the positive bearing of the catch element 42 of the holding element 26 in the recess of the sealing element 26, is also brought out of contact with the valve seat 8, so that a part of the medium can escape out of the pressure region 4, until the pressure of the medium in the pressure region 4 falls below the limit pressure p.sub.g. The force F.sub.D is then no longer greater than the holding force F.sub.H. The sealing body 12 moves back, and the sealing element 24 comes back into sealing contact on the valve seat 8, whereas the sealing body 12 with its contact surface 25 comes into contact with the rest surface 10, where by the safety valve is closed again.

(18) In the alternative embodiment shown in FIG. 4 by way of a sketch, a sealing body 12′ is designed similarly to the sealing body 12, and comprises a recess 18, in which a sealing element 24′ with a seal having a sealing lip 30′ and which is arranged in a groove 28 and is resilient or spring-biased and is arranged with a holding element 26, and these are held in the recess 18 via a nut 48. A resilient or spring-biased seal 30′ improves the media compatibility and temperature resistance compared to an O-ring 30. An annulus-shaped slot 50 is designed in the recess 18, in the side of the sealing body 12′ which faces the valve seat 8, in a manner such that a radially inner first part of the slot 50 which faces the longitudinal axis X is connected to the pressure channel 40, and a radially outer second part of the slot 50, which is away from the longitudinal axis X, is connected to the pressure space 38. The slot 50 thus permits a connection of the pressure channel 40 designed as a through-hole, to the pressure space 38, wherein this connection runs peripherally about the longitudinal axis X. A pressure impingement of the second side 34 of the sealing element 24′, as well as of the side of the sealing body 12′ which is formed lying opposite this second side 34, is not only ensured close to the pressure channel 40, but also completely peripherally about the longitudinal axis X. An equally distributed pressure build-up in the pressure space 38 likewise improves a level lifting of the sealing body 12 from the rest surface 10 of the valve body 2.

(19) It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.