Valve

Abstract

Valve for a gaseous medium, comprising a) a valve body (1) comprising an active part (3) with a main valve seat (13) and a control part (4) with a vent valve seat (30), which are formed on opposite end regions of a connecting body (2) which has a connecting channel (14) with an outlet (28) for the medium, b) a main valve chamber (12) formed in the working part (3), to which an inlet (27) for the medium is associated and in which a main sealing element (15) that can be pressed against the main valve seat (13) is mounted, c) a venting valve chamber (29) connected to a venting channel (44) and formed in the control part (4), in which a venting sealing element (31) for the venting valve seat (30) is mounted, d) a plunger (18) which is axially displaceable in the connecting channel (14) and which connects the main sealing body (15) and the vent sealing body (31) in such a way that the vent valve seat (30) is open when the main valve seat (13) is closed, e) a disc spring diaphragm (35) which co-delimits the vent valve chamber (29), is attached to the plunger (18) and is associated with the vent sealing element (31) such that the spring force of the disc spring diaphragm (35) is directed away from the vent valve seat (30), and f) a pressure chamber (41) which is bounded by the disc spring diaphragm (35) and a closure cover (40) which has an air connection (42), characterized in that g) that the main sealing body (15) and the vent sealing body (31) each have a seal holder (16, 32) and a seal (17, 33) which is designed as an annular seal and is mounted in an annular groove of the seal holder (16, 32), and that the main sealing body (15) and the vent sealing body (31) are each arranged on an end part (20, 21) of the plunger (18) whose diameter is smaller than the diameter of the middle part (19) of the plunger (18), h) that a flat disc spring (24) is provided in the working part (3), which is penetrated by the end part (20) of the plunger (18) and coaxially centers the latter and rests with a central area on the lower side of the seal holder (16), i) that in the control part (4) a flat disc spring diaphragm (35) is provided which is penetrated by the end part (21) of the plunger (18) and coaxially centers the latter, rests on the seal holder (32) with a central surface area on the upper side and has a spring disc (37) which is embedded in a medium-tight elastomer covering (38), j) that a collar (5) is formed on the connecting body (2) of the valve body (1) between the active part (3) and the control part (4), which is slightly larger in diameter than the active part (3) and slightly smaller than the control part (4), and that the active part (3), the control part (4) and the collar (5) each have a sealing ring (7, 8, 9) on their circumference, which are each mounted in an annular groove.

Description

[0001] The invention relates to a valve having the features of the preamble of claim 1.

[0002] US Patent 3,042,072 A discloses a diaphragm valve whose valve body has a connecting body with an active part and a control part, which have sealing rings mounted on their circumference and are of the same diameter. Furthermore, the valve body has corrugated diaphragms in the active part and the control part, which are mounted by means of sealing beads at the ends of an axially displaceable plunger, wherein frustoconically inclined sealing bead surfaces engage in funnel-shaped, inclined valve seats.

[0003] EP 1 484 540 A1 discloses a pneumatic valve with a valve body in which a plunger supporting valve seat seals is axially displaceable. A diaphragm made of an elastic material and with a corrugated cross-section is associated with the plunger.

[0004] DE 198 51 143 B4 discloses a solenoid valve with a disc-shaped magnetic armature that includes a sealing plate for a valve seat. The sealing plate consists of a disc-shaped flat spring and an elastomer sheath that encloses the flat spring on both sides.

[0005] DE 20 17 776 A discloses a three-way valve which has a plunger which can be axially displaced in a valve body, on which two valve discs are provided which alternately move into an open or closed position, wherein at least one of the valve discs has an elastic intermediate part.

[0006] US Patent 5,261,442 A discloses a diaphragm valve with leak detection for various liquids. The valve body contains two diaphragms and two valve seats positioned opposite each other, between which an axially displaceable plunger with corresponding valve seat seals is mounted.

[0007] The object of the invention is to further develop a valve of this type in such a way that a high level of safety and permanently reliable control, opening and closing function can be achieved using simple means.

[0008] This problem is solved according to the invention by the features of claim 1.

[0009] Advantageous embodiments and further developments of the invention are characterized by the features of the dependent claims.

[0010] Further advantages and essential details of the invention can be found in the following description and the drawing, which schematically shows a preferred embodiment as an example.

[0011] The valve according to the invention is shown enlarged in a sectional view in the drawing. It is designed as a pneumatically controlled three-way valve intended for a gaseous medium. In its unactuated rest position, the valve is in the closed position. It comprises a valve body 1, which has a connecting body 2. A lower working part 3 and an upper control part 4 are arranged on the connecting body 2. Between the working part 3 and the control part 4, the valve body 1 has a collar 5 formed on the connecting body 2. The connecting body 2, the collar 5, the working part 3, and the control part 4 are manufactured as a prefabricated, one-piece unit made of a single material and are concentric with respect to a central axis 6. A further embodiment of the valve can also be a two-way design with an inlet 27 and an outlet 28, which is not described in detail here.

[0012] The drawing shows that the diameter of the collar 5 is significantly larger than the remaining diameter of the connecting body 2. In contrast, the functional part 3 has a slightly smaller diameter than the collar 5, while the control part 4 has a slightly larger diameter than the collar 5. Both the functional part 3 and the collar 5, as well as the control part 4, each have an annular groove on their circumference, in which a sealing ring 7, 8, 9 is mounted. The sealing rings 7, 8, 9 can advantageously be made of an elastomer. It can also be seen that the valve body 1 has a radially projecting, annular or flange-shaped collar 10 at its top, which is formed from the same material on the control part 4 and extends beyond the sealing ring 9.

[0013] The functional part 3 has a base wall and a circumferential wall 11, which together define a main valve chamber 12. A main valve seat 13, coaxial with the central axis 6, is formed on the base wall. This seat connects to a connecting channel 14 of the same diameter, which is coaxially formed in the connecting body 2, and projects slightly into the main valve chamber 12. The main valve seat 13 is closed by a main sealing element 15, which is coaxially mounted in the main valve chamber 12 and comprises a seal holder 16 and an annular seal 17. The seal 17, which preferably consists of an elastomer, lies in an annular groove of the seal holder 16 and seals the main valve seat 13.

[0014] The main sealing element 15 is arranged on a plunger 18, which is located coaxially with the central axis 6 in the connecting channel 14 of the connecting body 2. The plunger 18 has a central section 19 as well as a lower end section 20 and an upper end section 21, as shown in the drawing. The diameter of the end sections 20, 21 is smaller than the diameter of the central section 19, so that shoulders 22, 23 are formed. The lower end section 20 passes through the seal holder 16 of the main sealing element 15 in a closely matched bore and is supported by a surface section facing the main valve seat 13 on the shoulder 22 of the plunger 18.

[0015] In the working part 3, a flat disc spring 24 is provided, which is penetrated by the end part 20 of the tappet 18 and coaxially centers the latter. The disc spring 24 rests with a central region against the lower side of the seal holder 16 and is supported with a circumferential edge against a stepped stop 25 formed on the circumferential wall 11 of the working part 3. The drawing shows that the diameter of the disc spring 24 is significantly larger than the diameter of the main valve seat 13. Advantageously, the diameter of the disc spring 24 can be approximately 2.5 to 2.9 times larger than the main valve seat 13, with the factor preferably being approximately 2.7.

[0016] The disc spring 24 can be designed such that, in addition to its function of coaxially centering the plunger 18, it also helps to hold the main sealing element 15 in the closed position shown. However, it can also be advantageous to design the disc spring 24 so that it presses the main sealing element 15 against the main valve seat 13 with a small or large force.

[0017] A fastening element 26 is slid onto the end part 20 of the plunger 18. In a preferred embodiment, this fastening element is designed as a clamping disc, which, after being slid onto the end part 20, is self-retainingly positioned on the latter. This ensures that the disc spring 24 and the main sealing element 15, which rests against the shoulder 22, are immovably connected to the plunger 18. The downward-facing side of the active part 3, as shown in the drawing, serves as the inlet 27 for the medium, which enters the main valve chamber 12 through openings formed in the disc spring 24. The outlet 28 for the medium is formed in the wall of the connecting body 2 in the area between the active part 3 and the collar 5.

[0018] The control part 4 has a coaxial venting chamber 29 into which a venting valve seat 30, coaxial with the central axis 6, projects slightly and connects to the connecting channel 14 of the connecting body 2, which has the same diameter. In the area between the control part 4 and the collar 5, the valve body 1 has a venting channel 44 through which the medium coming from the venting valve chamber 29 can escape. A venting sealing element 31 is associated with the venting valve seat 30. This element is coaxially mounted in the venting valve chamber 29 and has a seal holder 32 and an annular seal 33. The vent sealing element 31 is arranged on the upper end part 21 of the plunger 18 by the end part 21 passing through the seal holder 32 in a closely fitted bore and is supported by a surface part facing the vent valve seat 30 on the shoulder 23 of the plunger 18.The seal 33, which preferably consists of an elastomer, lies in an annular groove of the seal holder 32 and is intended for sealing the vent valve seat 30. In the drawing, the vent sealing element 31 is in the open position, so that there is a gap 34 between the vent valve seat 30 and the vent sealing element 31, which corresponds to the axial stroke of the plunger 18.

[0019] In the control section 4, a flat disc spring diaphragm 35 is provided, which is penetrated by the end section 21 of the plunger 18 and coaxially centers the latter. The disc spring diaphragm 35 rests with a central surface area on the upper side of the seal holder 32 and is supported with a circumferential edge area on a step 36 formed on the wall of the control section 4. The disc spring diaphragm 35 consists of a thin spring disc 37 embedded in an elastomer covering 38, thus providing a hermetic seal that reliably prevents the passage of a gaseous medium. In a preferred embodiment, the spring disc 37 is vulcanized into the elastomer covering 38 both between different spring struts and on opposite side surfaces, largely without voids, so that an intimate bond between the spring disc 37 and the elastomer covering 38 is achieved, resulting in a compact assembly.The drawing shows that the diameter of the disc spring diaphragm 35 is considerably larger than the diameter of the vent valve seat 30. Advantageously, the diameter of the disc spring diaphragm 35 can be approximately 2.5 to 2.9 times larger than the vent valve seat 30, with the factor preferably being approximately 2.7.

[0020] The disc spring diaphragm 35 can be designed such that, in addition to coaxially centering the plunger 18, it significantly contributes to holding the vent sealing element 31 in the open position shown. For this purpose, it is advantageous to design the disc spring diaphragm 35 with the spring washer 37 such that, in the unactuated normal rest position, it reliably lifts the elastomer sealing element 31 from the vent valve seat 30 with a relatively large force and, via the plunger 18, presses the main sealing element 15 tightly against the main valve seat 13. For various applications, it can be particularly advantageous to design the disc spring diaphragm 35 of the control part 4 such that its spring force is greater than the force of the disc spring 24 of the active part 3.

[0021] A fastening element 39 is slid onto the upper end part 21 of the plunger 18. In a preferred embodiment, this fastening element is also designed as a clamping disc, which, after being slid onto the end part 21, is self-retainingly positioned on the latter. This ensures that the disc spring diaphragm 35 and the vent sealing element 31, which rests against the shoulder 23, are immovably and firmly connected to the plunger 18.

[0022] The control section 4 of the valve body 1 has a sealing cap 40 at its top. This cap is arranged coaxially with the central axis 6 in the plane of the collar 10 and rests on an edge surface of the control section 4. The diameter of the sealing cap 40 is dimensioned such that it fits tightly and securely against an inner surface of the side wall of the control section 4 when the valve is assembled by pressing it in. In this process, the sealing cap 40 presses firmly against the circumferential edge of the disc spring diaphragm 35 with a flat portion from above, thus ensuring a reliable seal. In the area above the disc spring diaphragm 35, the sealing cap 40 has a recess for a pressure chamber 41, in which the upper plunger end part 21 and the fastening element 39 are located.The concentric pressure chamber 41 is designed with a diameter such that the pressure surface 42 of the disc spring diaphragm 35, which also limits the pressure chamber 41, is larger than the clear cross-sectional area of ​​the vent valve seat 30. Above the plunger end part 21, the sealing cover 40 has a concentric air connection 42 designed as a bore, through which, for example, a pneumatic control medium of a three-way pilot valve (not shown here) can be introduced into and also introduced out of the pressure chamber 41.

[0023] The drawing also clearly shows that the connecting channel 14, as well as the main valve seat 13 and the vent valve seat 30, are more than twice in diameter, i.e., significantly larger, than the central part 19 of the plunger 18. Since the connecting channel 14 and the plunger 18 are concentric with respect to the central axis 6, the plunger 18 is surrounded by an annular gap 43, which is provided for the medium. To allow the medium to flow unhindered from the main valve chamber 12 through the main valve seat 13 to the outlet 28 when the valve is open, and to vent through the vent valve seat 30 into the vent valve chamber 29 and the vent channel 44 when the valve is closed (as shown in the drawing), the axial stroke of the plunger 18, and thus also the distance 34 between the open main valve seat 13 and the main sealing body 15, is determined by the valve's design.between the open vent valve seat 30 and the open vent valve body 31 such that the annular free cross-sectional area in the region of the circumference of the open main valve seat 13 or the circumference of the open vent valve seat 30 is at least equal to the cross-sectional area of ​​the annular gap 43.

[0024] The valve according to the invention is designed such that it can be inserted into a receiving bore, for example, of an actuator housing (not shown here), with the necessary seals in the receiving bore being achieved via the sealing rings 7, 8, 9. The actuator can, for example, be a single-acting pneumatic cylinder whose spring-loaded piston can be moved in one direction by means of supplied compressed air and, when the cylinder is vented, is pushed back into its initial position by the force of the spring.

[0025] As already mentioned, the valve shown is in its closed position. In this position, the compressed air supplied through inlet 27 is present in the main valve chamber 12 and additionally presses the main sealing element 15 against the main valve seat 13 by the force of the disc spring diaphragm 35 and, if applicable, also the disc spring 24.

[0026] When control air is supplied to the valve via the pilot valve (not shown here), which can be a solenoid valve, this air enters the pressure chamber 41 through the air port 42 and acts on the diaphragm 35. Once the pressure of the control air has increased to a level greater than the combined opposing forces of the diaphragm 35, the disc spring 24, and the incoming compressed air, the diaphragm 35 is forced downwards, pressing the vent seal 31 tightly against the vent valve seat 30. Simultaneously with the displacement of the vent seal 31, the plunger 18 and the main seal 15 are also displaced downwards, with the latter lifting off the main valve seat 13 by a distance of 34. This displacement of the main seal 15 causes the disc spring 24 to be forced downwards.

[0027] Through the main valve seat 13, which is now open, compressed air flows from the main valve chamber 12 into the annular gap 43 and from there through the outlet 28 into the actuator cylinder, thereby moving its piston against the spring force. This operating state is maintained as long as the control air is present in the pressure chamber 41 of the control unit 4.

[0028] When the actuator, and thus also the valve according to the invention, is to be returned to its previous initial or rest state, the pilot valve must be deactivated so that the control air supply is shut off and the control element 4 is vented, with the control air escaping from the pressure chamber 41 through the air connection 42. Thus, the disc spring diaphragm 35, the disc spring 24, and the compressed air present at the vent valve seat 30 push the vent sealing element 31 upwards into the opening position shown, whereby the main sealing element 15 simultaneously closes the main valve seat 13 again via the plunger 18. The actuator piston is pushed back in the cylinder by the spring, so that the latter is vented and the compressed air in the cylinder escapes to the atmosphere through the outlet 28, the annular gap 43, the vent valve seat 30, the vent valve chamber 29, and the vent channel 44.

[0029] For various applications, it can be advantageous to operate the valve according to the invention not only in the closed or open end position, but also in intermediate positions, which are preferably continuously or finely adjustable, so that the compressed air supplied to the consumer, e.g., actuator, can be precisely metered. For this purpose, it can be advantageous to design the valve with a proportional control function, wherein the stroke of the plunger 18 is preferably proportional to the control air pressure introduced into the pressure chamber 41. This also allows the distance 34 between the main valve seat 13 and the main sealing element 15, or between the vent valve seat 30 and the vent sealing element 31, to be adjusted proportionally to the control air pressure. Furthermore, it can be advantageous to design the disc spring diaphragm 35 such that the spring characteristic of the spring disc 37 embedded in the elastomer covering 38 is not linear, but progressive.This makes it possible to keep the sealing elements 15, 31 in equilibrium or their distances 34 in the desired positions via the control air pressure. To enable precise and largely automatic proportional control, a flow meter (not shown) can preferably be assigned to the output 28 of the valve body 1. The measurement results of this flow meter are transmitted continuously or at intervals to a pressure regulator (also not shown), which, based on the measurement results, sets, maintains, or adjusts the pressure of the control air according to the respective requirements.

[0030] A significant advantage is that a powerful, large volume of compressed air is supplied to the actuator via the valve according to the invention, which can be controlled by means of a small pilot valve, to meet high requirements, whereby in particular a long-lasting high safety and a permanently reliable functioning of the force-amplifying valve are ensured by the special, structurally integrated, disc spring diaphragm 35 in the control part 4.

Claims

[1] Valve for a gaseous medium comprising a) a valve body (1) comprising an active part (3) with a main valve seat (13) and a control part (4) with a vent valve seat (30), which are formed on opposite end regions of a connecting body (2) which has a connecting channel (14) with an outlet (28) for the medium, b) a main valve chamber (12) formed in the working part (3), to which an inlet (27) for the medium is associated and in which a main sealing element (15) that can be pressed against the main valve seat (13) is mounted, c) a venting valve chamber (29) connected to a venting channel (44) and formed in the control part (4), in which a venting sealing element (31) for the venting valve seat (30) is mounted, d) a plunger (18) which is axially displaceable in the connecting channel (14) and which connects the main sealing body (15) and the vent sealing body (31) in such a way that the vent valve seat (30) is open when the main valve seat (13) is closed, e) a disc spring diaphragm (35) which co-delimits the vent valve chamber (29), is attached to the plunger (18) and is associated with the vent sealing element (31) such that the spring force of the disc spring diaphragm (35) is directed away from the vent valve seat (30), and f) a pressure chamber (41) bounded by the disc spring diaphragm (35) and a closure cover (40) which has an air port (42), characterized by , g) that the main sealing body (15) and the vent sealing body (31) each have a seal holder (16, 32) and a seal (17, 33) which is designed as an annular seal and is mounted in an annular groove of the seal holder (16, 32), and that the main sealing body (15) and the vent sealing body (31) are each arranged on an end part (20, 21) of the plunger (18) whose diameter is smaller than the diameter of the middle part (19) of the plunger (18), h) that a flat disc spring (24) is provided in the working part (3), which is penetrated by the end part (20) of the plunger (18) and coaxially centers the latter and rests with a central area on the lower side of the seal holder (16), i) that in the control part (4) a flat disc spring diaphragm (35) is provided which is penetrated by the end part (21) of the plunger (18) and coaxially centers the latter, rests on the seal holder (32) with a central surface area on the upper side and has a spring disc (37) which is embedded in a medium-tight elastomer covering (38), j) that a collar (5) is formed on the connecting body (2) of the valve body (1) between the active part (3) and the control part (4), which is slightly larger in diameter than the active part (3) and slightly smaller than the control part (4), and that the active part (3), the control part (4) and the collar (5) each have a sealing ring (7, 8, 9) on their circumference, which are each mounted in an annular groove. [2] Valve according to the preceding claim, characterized by, that the main valve seat (13) and the vent valve seat (30) are designed to point in opposite directions at the end regions of the connecting body (2) and the main sealing body (15) and the vent sealing body (31) are arranged facing each other on the plunger (18). [3] Valve according to one or more of the preceding claims, characterized by , that the diameter of the connecting channel (14) is larger than the diameter of the plunger (18) located in the latter and that an annular gap (43) surrounding the plunger (18) is formed in the connecting body (2) for the medium. [4] Valve according to one or more of the preceding claims, characterized by , that the sealing elements (15, 31) are supported on each shoulder (22, 23) of the plunger (18). [5] Valve according to one or more of the preceding claims, characterized by, that the disc spring (24) is arranged on the side of the main sealing body (15) facing away from the main valve seat (13) and that the disc spring diaphragm (35) is arranged on the side of the vent sealing body (31) facing away from the vent valve seat (30). [6] Valve according to one or more of the preceding claims, characterized by , that a circumferential edge of the disc spring (24) is supported on a stop (25) of the working part (3) and a circumferential edge part of the disc spring diaphragm (35) is supported on a step (36) of the control part (4). [7] Valve according to one or more of the preceding claims, characterized by , that the disc spring (24) is approximately 2.5 to 2.9 times larger in diameter in relation to the main valve seat (13) and the disc spring diaphragm (35) is approximately 2.7 to 2.5 times larger in diameter in relation to the vent valve seat (30). [8] Valve according to one or more of the preceding claims, characterized by, that the circumferential edge part of the disc spring diaphragm (35) is pressure-tightly fixed to the step (36) of the control part (4) by means of the closure cover (40). [9] Valve according to one or more of the preceding claims, characterized by , that the spring force of the disc spring diaphragm (35) in the control part (4) is greater than the force of the disc spring (24) in the working part (3). [10] Valve according to one or more of the preceding claims, characterized by , that a pressure surface of the disc spring diaphragm (35) facing the pressure chamber (41) in the control part (4) is larger than the clear cross-sectional area of ​​the vent valve seat (30). [11] Valve according to one or more of the preceding claims, characterized by , that the control part (4) of the valve body (1) has a radially projecting collar (10). [12] Valve according to one or more of the preceding claims, characterized by, that the valve body (1), the plunger (18), the main sealing body (15), the disc spring (24), the vent sealing body (31), the disc spring diaphragm (35), the fastening elements (26, 39) and the sealing cap (40) are designed coaxially with respect to a central axis (6). [13] Valve according to one or more of the preceding claims, characterized by , that the axial stroke of the plunger (18) is dimensioned such that the annular free cross-sectional area in the region of the circumference of the open main valve seat (13) or the circumference of the open vent valve seat (30) is at least equal to the cross-sectional area of ​​the annular gap (43). [14] Valve according to one or more of the preceding claims, characterized by, that the stroke of the plunger (18) and the distance (34) between the main valve seat (13) and the main sealing body (15) and / or the vent valve seat (30) and the vent sealing body (31) are proportional to the control air pressure introduced into the pressure chamber (41).

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