Drive for a process valve, method for operating the drive, and process valve
Patent Information
- Application Number
- EP2023733340
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-06-29
- Filing Date
- 2023-06-19
- Publication Date
- 2025-05-07
AI Technical Summary
Existing process valve drives require multiple components and pistons to achieve different strokes, leading to increased wear, complexity, and size, while failing to effectively manage foaming during filling processes.
A drive mechanism with a single movable piston and a stroke divider, supported by compression springs, allows for two distinct strokes (primary and secondary) using a single piston, reducing component count and wear, and enabling adjustable intermediate positions to manage foaming by varying the distance between the stroke divider and piston.
This configuration enables efficient operation with reduced components and wear, allowing for effective foaming reduction during filling processes, and provides a compact design by utilizing a single piston for multiple functions, typically requiring multiple valves or drives.
Smart Images
Figure 1.1
Abstract
Description
[0001] Title : Actuator for a process valve , method for
[0002] Operating the actuator and process valve
[0003] Description
[0004] The invention relates to a drive for a process valve, a method for operating the drive and a process valve.
[0005] The problems of the state of the art are solved by :
[0006] A drive according to claim 1, a method according to a dependent claim and a process valve according to a further dependent claim.
[0007] One aspect of the description concerns the following subject matter:
[0008] A drive for a process valve comprising: a drive piston which is movably mounted within a drive housing along an actuating axis and divides an interior of the drive housing into a control chamber connected to an actuating fluid connection and a further chamber; at least one first compression spring which is supported on the drive housing and on an associated section of the drive piston and which presses the drive piston towards a rest position of the drive piston; at least one stroke divider which is movably mounted along the actuating axis and which limits a primary stroke of the drive piston in a first end position oriented in the direction of the drive piston, and which limits a secondary stroke of the drive piston in a second end position oriented away from the drive piston;and at least one second compression spring, which is supported on the drive housing and on the stroke divider, and which presses the stroke divider in the direction of the drive piston.;
[0009] The proposed design requires only a single drive piston to realize two different strokes. Thus, only one bearing and one seal for the drive piston are required. The design of the stroke divider allows for an intermediate position between the primary and secondary strokes to be varied.
[0010] By dividing the stroke into a primary stroke and a secondary stroke, functions that would normally require multiple valves or a differently designed drive can be implemented using a single proposed drive. For example, when filling foaming process media, the primary stroke can help reduce or prevent foaming during filling or during the final filling, i.e., at the beginning and end of the filling process.
[0011] Compared to dual-piston drives, for example, this advantageously results in a reduction in the number of components. Furthermore, wear is reduced because the stroke divider is more resilient to malfunctions. Furthermore, the drive provided is smaller.
[0012] For example, it is advantageous that the distance between the stroke divider and the drive piston corresponds to the primary stroke when the drive piston is in its rest position.
[0013] For example, it is advantageous that a distance between a stop which is arranged fixedly to the drive housing at least during operation and a counter-stop of the stroke divider assigned to the stop corresponds to the secondary stroke when the stroke divider is in its first end position.
[0014] It is advantageous, for example, that a stroke limiter which is arranged fixedly relative to the drive housing at least during operation provides a stop for the stroke divider, wherein the stop of the stroke limiter limits the first end position of the stroke divider.
[0015] Advantages are achieved by the stroke divider providing a stop facing the drive piston, wherein the stop of the stroke divider limits an intermediate position of the drive piston when a counter-stop of the drive piston associated with the stop encounters the stop of the stroke divider. It is advantageous, for example, that the position of the counter-stop is adjustable along the actuating axis.
[0016] This example makes it possible to adjust both the end position and the intermediate position together.
[0017] Furthermore, it is advantageous, for example, that the position of the stroke limiter can be adjusted along the adjusting axis.
[0018] This allows the intermediate position between primary stroke and secondary stroke to be advantageously adjusted.
[0019] One aspect of the description relates to the following subject matter: A method for operating the drive according to the previous aspect, comprising: applying, by means of a control unit, a first pressure as a control pressure, so that the drive piston, starting from its rest position, travels through the primary stroke to an intermediate position; and applying, by means of the control unit, a second pressure as a control pressure, which is greater than the first pressure, so that the drive piston, starting from the intermediate position, travels through the secondary stroke to an end position.
[0020] The drawing shows:
[0021] Figure 1 shows a process valve in a schematic
[0022] sectional view;
[0023] Figures 2, 3, 5 each show a pneumatic actuator for the process valve in a schematic sectional view; and Figure 4 shows a schematic time diagram with respective
[0024] Pressure and stroke curves.
[0025] Figure 1 shows a schematic view of a process valve 200. A drive 100 is, for example, a pneumatic drive and comprises a drive piston 104 which is movably mounted within a drive housing 102 along an actuating axis S. The drive piston 104 divides an interior of the drive housing 102 into a control chamber 108 connected to an actuating fluid connection 106 and a further chamber 110. The drive piston 104 is fixedly or rigidly connected to an actuating rod 112. Alternatively, an elastic element in the force path or another type of force-transmitting coupling, i.e. in particular between the drive piston 104 and a shut-off body, can be provided between the actuating rod 112 or a part thereof.
[0026] At least one first compression spring 114 is supported on the drive housing 102 and on an associated portion 116 of the drive piston 104. The at least one first compression spring 114 presses the drive piston 104 toward a rest position R_104 of the drive piston 104.
[0027] At least one stroke divider 120, which is movably mounted along the actuating axis S, limits a primary stroke H1 of the drive rod 112 or the primary stroke H1 of the drive piston 104 in a first end position oriented in the direction of the drive piston 104 - that is to say when the stroke divider 120 is in this first end position. The stroke divider 120 limits a secondary stroke H2 of the drive rod 111 or the secondary stroke H2 of the drive piston 104 in a second end position oriented away from the drive piston 104. A second compression spring 124 is supported on the drive housing 102 and on the stroke divider 120 and presses the stroke divider 120 in the direction of the drive piston 104.
[0028] It is shown that a distance between the stroke divider 120 and the drive piston 104 corresponds to the primary stroke Hl when the drive piston 104 is in its rest position R_104.
[0029] In other words, the primary stroke Hl is determined by a minimum distance between the drive piston 104 and the stroke divider 120 when both the drive piston 104 and the stroke divider 120 are in their rest position, in which the compression springs 114 and 124 have their maximum extension along the actuating axis S in the installed state.
[0030] The compression springs 114 and 124 are thus supported on an inner wall of a cover of the drive housing 102.
[0031] It is also shown that a distance between a stop 122, which is arranged fixedly relative to the drive housing 102 at least during operation of the drive 100, and a counter-stop 123 of the stroke divider 120 assigned to the stop 122 corresponds to the secondary stroke H2 when the stroke divider 120 is in its first end position R_120.
[0032] In other words, the secondary stroke H2 is determined by a minimum distance between the stroke divider 120 and the stop 122 which is fixed to the drive housing 102 when the stroke divider 120 is in its rest position, in which the compression spring 124, in the installed state, has its maximum extension along the adjusting axis S. In an example not shown, a further stroke limiter is provided which comprises the stop 122 for the stroke divider 120. This further stroke limiter - and thus the stop 122 - is designed to be adjustable along the adjusting axis S, for example via intermeshing threads of the drive housing 102 and the further stroke limiter. During operation of the drive 100, the stop 122 is fixed to the drive housing 102 and limits the end position of the drive piston 104 or the end position of the drive rod 112.
[0033] A position of the stop 122 along the actuating axis S is adjustable and fixed during operation of the drive 100.
[0034] A stroke limiter 130, which is arranged fixedly relative to the drive housing 102 at least during operation, provides a stop 132 for the stroke divider 120, wherein the stop 132 of the stroke limiter 130 limits the first end position of the stroke divider 120.
[0035] The stop 132 is provided by at least one surface of the stroke limiter 130 facing away from the drive piston 104.
[0036] The stroke limiter 132 guides the stroke divider 120 along the adjusting axis S .
[0037] The position of the stroke limiter 130 can be adjusted along the adjusting axis S. For this purpose, the stroke limiter 130 has an external thread which engages with an internal thread fixed to the drive housing 102. The position of the stroke limiter 130 can be adjusted by means of a tool engaging with the stroke limiter 130. For example, an internal thread fixed to the drive housing 102 is provided, in which internal thread the stroke limiter 130 is held by means of an external thread. The position of the stroke limiter 130 along the adjusting axis, and thus the intermediate position, can be adjusted by means of the rotational position of the stroke limiter 130.
[0038] If a counter stop 133 of the stroke divider 120 and the stop 132 of the stroke limiter 130 are in contact with each other, then the first end position R_120 of the stroke divider 130 is reached.
[0039] The stroke divider 120, which is shaped in sections like a cylinder jacket, is mounted linearly along the actuating axis S by means of the stroke limiter 130. The stroke limiter 130 is also designed in sections like a cylinder jacket.
[0040] The stop 132 is provided by an outwardly projecting collar 136 of the stroke limiter 130. An inwardly projecting collar 138 of the stroke divider 120 engages around the collar 136.
[0041] An outwardly projecting collar 140 of the stroke divider 120 provides a contact surface 142 for the second compression spring 124, facing away from the drive piston 104. Furthermore, the collar 140 provides the stop 126, which establishes the position of the intermediate position between the primary stroke H1 and the secondary stroke H2.
[0042] In one example, the collar 140 is not fully formed in the circumferential direction, but rather interrupted, and in a more extensive example, it may also resemble a type of crown. In the aforementioned examples, radially outwardly projecting elements form the collar 140 and an interrupted contact surface 142.
[0043] The process valve 200 is designed, for example, as a seat valve or diaphragm valve. The process valve 200 comprises a valve body 210 which is arranged fixedly relative to the drive housing 102 and which comprises a fluid channel (not shown) which carries a process fluid. The fluid channel connects at least two fluid connections 230 and 240 to one another in a fluid-conducting manner. The flow through the fluid channel is determined by a position of a shut-off body 250. The position of the shut-off body 250, in cooperation with a valve seat in the valve body 210, limits the flow of the process fluid through the valve body 230. The shut-off body 250 is mechanically connected to the drive rod 112. The position or stroke of the drive rod 112 therefore determines the position of the shut-off body 250.
[0044] The process valve 200 is shown in Figure 1 as an example in a normally closed state, which means that the shut-off body 250 rests against the valve seat without any effective control pressure applied and no fluid can flow between the connections 220 and 230.
[0045] In this case, the total stroke is composed of the primary stroke H1 and the secondary stroke H2. The rest position R_104 of the drive piston 104 can be defined, for example, by the position of the valve seat in the valve body 210 and the shut-off body 250. The primary stroke H1 is limited, on the one hand, by the pressing of the shut-off body 250 onto the valve seat and, on the other hand, by the first end position of the stroke divider H1. The control pressure in the control chamber 108 works against the force of the compression spring 114.
[0046] A method for operating the drive 100 comprises: applying, by means of a control unit 300, a first pressure p1 as the control pressure p, so that the drive rod 112, starting from its rest position R_104, travels through the primary stroke H1 to an intermediate position Z; and applying, by means of the control unit 300, a second pressure p2 as the control pressure p, which is greater than the first pressure P1, so that the drive rod 112, starting from the intermediate position Z, travels through the secondary stroke H2 to an end position E.
[0047] The control unit 300 generates the control pressure p with the pressure value pl, the pressure value p2 or the ambient pressure value in dependence on a control signal c in order to set the intermediate position, the end position or the rest position of the valve rod 112 or the drive piston 104.
[0048] The application of the control pressure p means that so much control fluid or actuating fluid is supplied to or removed from the control chamber 108 that the desired control pressure p prevails within the control chamber 108.
[0049] Figure 2 shows a state of the drive 100 in which, starting from Figure 1, the primary stroke H1 has already been completed. For example, it is shown that the stroke divider 120 provides a stop 126 facing the drive piston 104, wherein the stop 126 of the stroke divider 120 limits the intermediate position Z of the drive piston 104 when a counter-stop 128 of the drive piston 104, associated with the stop 16, strikes the stop 126 of the stroke divider 120.
[0050] When the drive piston 104 encounters the stop 126, it experiences a counterforce caused by the second compression spring 124. In the intermediate position Z of the drive piston 104, the forces of the first compression spring 114 and the second compression spring 124 act as a counterforce to the force generated by the control pressure p in the control chamber 108 on the drive piston 104.
[0051] The first outer compression spring 114 is effective for the primary stroke H1, whereas the second compression spring 124 initially has no effect when passing through the primary stroke H1. After the drive piston 104 impacts the stroke divider 120, the force generated by the two compression springs 114, 124 must be overcome by means of a control pressure p in the control chamber 108 increased to the pressure value p2 in order to achieve the secondary stroke H2 in the direction of the end position opposite the rest position of the drive piston 104.
[0052] The first compression spring 114 has a larger diameter than the second compression spring 124. The second compression spring 124 is located inside the first compression spring 114. The stroke divider 120 is located partially inside the second compression spring 124. The stroke limiter 130 is located between the drive rod 112 and the stroke divider 120 in a section perpendicular to the actuating axis S. Figure 3 shows the drive 100, in which the drive piston 104 and thus the drive rod 112 are in an end position E opposite the rest position. In the end position E, the control pressure p in the control chamber 108 has been increased to the pressure value p2 from Figure 1 to such an extent that the forces of the two compression springs 114, 124 counteracting the control pressure p have been overcome. The drive piston 104 and the stroke divider 120 lie directly against one another. The stroke divider 120 rests on the drive housing 102 via the counter stop 123.In other words, the end position E of the drive piston 104 is reached when both the stroke divider 120 rests against the stop 122 and the drive piston 104 rests against the stroke divider 120.
[0053] Figure 4 shows an example of the time course of the control pressure p and the time course of the stroke H . At time t1 the drive piston begins to move out of the rest position R_104 after the control pressure p has been increased to the pressure value pl at time t0 . At time t2 the drive piston reaches the intermediate position Z . The pressure value pl is not sufficient to additionally compress the second compression spring, which is why the drive piston remains in the intermediate position when the pressure value pl is applied. Starting from time t3 the control pressure p is increased further in the direction of the pressure value p2 , which is reached at time t5 . Even before the pressure value p2 is reached the drive piston begins to move out of the intermediate position Z in the direction of the end position E at time t4, which is reached at time t6.In contrast to Figures 1 to 3, Figure 5 shows the drive 100 for implementing an operating mode or control function that is reversed compared to Figures 1 to 3. For example, a normally open process valve 200 can be provided with the same valve body 210 instead of the normally closed position. For the rest, reference is made to the description of Figures 1 to 3.
Claims
Patent claims A drive (100) for a process valve (200) comprising: a drive piston (104) which is movably mounted within a drive housing (102) along an actuating axis (S), which divides an interior of the drive housing (102) into a control chamber (108) connected to an actuating fluid connection (106) and a further chamber (110); at least one first compression spring (114) which is supported on the drive housing (102) and on an associated section (116) of the drive piston (104), and which presses the drive piston (104) in the direction of a rest position (R_104) of the drive piston (104); at least one stroke divider (120) which is movably mounted along the actuating axis (S) and which, in a first end position oriented in the direction of the drive piston (104), limits a primary stroke (H1) of the drive piston (104), and which, in a second end position oriented away from the drive piston (104), limits a secondary stroke (H2) of the drive piston (104);and at least one second compression spring (124) which is supported on the drive housing (102) and on the stroke divider (120) and which presses the stroke divider (120) in the direction of the drive piston (104); 2. The drive (100) according to claim 1, wherein a distance between the stroke divider (120) and the drive piston (104) corresponds to the primary stroke (Hl) when the drive piston (104) is in its rest position (R_104).
3. The drive (100) according to claim 1 or 2, wherein a distance between a stop (122) arranged fixedly to the drive housing (102) at least during operation and a counter-stop (123) of the stroke divider (120) associated with the stop (122) corresponds to the secondary stroke (H2) when the stroke divider (120) is in its first end position (R_120).
4. The drive (100) according to claim 3, wherein a position of the counter-stop (123) is adjustable along the actuating axis.
5. The drive (100) according to one of claims 1 to 4, wherein a stroke limiter (130) arranged fixedly at least during operation relative to the drive housing (102) provides a stop (132) for the stroke divider (120), wherein the stop (132) of the stroke limiter (130) limits the first end position of the stroke divider (120).
6. The drive (100) according to claim 5, wherein a position of the stroke limiter (130) along the actuating axis (S) is adjustable.
7. The drive (100) according to one of claims 1 to 6, wherein the stroke divider (120) provides a stop (126) facing the drive piston (104), wherein the stop (126) of the stroke divider (126) limits an intermediate position (Z) of the drive piston (104) when a counter-stop (128) of the drive piston (104) associated with the stop (16) strikes the stop (126) of the stroke divider (120).
8. The drive (100) according to one of the preceding claims, wherein the drive piston (104) is rigidly connected to a drive rod (112).
9. The drive (100) according to one of the preceding claims, wherein the first compression spring (114) is always and in every operating state of the drive (100) supported on the drive housing (102) and on the associated portion (116) of the drive piston (104).
10. The drive (100) according to one of the preceding claims, wherein the second compression spring (124) is always supported on the drive housing (102) and on the stroke divider (120) in every operating state of the drive (100).
11. The drive (100) according to one of the preceding claims, wherein the first compression spring (114) and the second compression spring (124) are arranged together in the further chamber (110) different from the control chamber (108).
12. The drive (100) according to one of the preceding claims, wherein the first compression spring (114) has a counterforce to the Passing through the primary stroke (H1), wherein the second compression spring (124) does not provide a counterforce for passing through the primary stroke (H1), and wherein the first and second compression springs (114, 124) together already share a counterforce for passing through the secondary stroke (H2). The drive (100) according to one of the preceding claims, wherein the drive piston (104) divides the interior of the drive housing (102) into the single control chamber (108) of the drive (100) and the further chamber (110). The drive (100) according to one of the preceding claims, wherein the first compression spring (114) and the second compression spring (124) are arranged within the further chamber (110). A method for operating the drive (100) according to one of the preceding claims, comprising: Applying, by means of a control unit (300), a first pressure (pl) as control pressure (p), so that the drive piston (104), starting from its rest position (R_104), travels through the primary stroke (Hl) to an intermediate position (Z); and Applying, by means of the control unit (300), a second pressure (p2) as control pressure (p), which is greater than the first pressure (Pl), so that the drive piston (104) travels through the secondary stroke (H2) starting from the intermediate position (Z) to an end position (E). A process valve (200) comprising the drive (100) according to one of claims 1 to 12. The process valve (200) according to claim 16, wherein the process valve (200) comprises a valve body (210) arranged stationary with respect to the drive housing (102), wherein the valve body (210) comprises a fluid channel fluidically connecting at least two fluid connections (230, 240) to one another for conducting a process fluid which differs from an actuating fluid which is supplied to the actuating fluid connection (106), wherein the flow through the fluid channel is determined by a position of a shut-off body (250), wherein the position of the shut-off body (250), in cooperation with a valve seat in the valve body (210), limits the flow of the process fluid through the valve body (230), and wherein the shut-off body 250 is mechanically connected to the drive rod (112).