ACTUATOR FOR A PROCESS PLANT

Abstract

The invention relates to an actuator (10) for a process plant, comprising an actuating valve (14) and an actuating drive (12) which has an actuating drive housing (20) and a drive rod (18) mounted in the actuating drive housing (20), wherein the actuating drive housing (20) is connected to a valve housing (22) of the actuating valve (14) via a connecting housing. The invention is characterized in that a second rod coupling (46) and an adjusting rod (42) are provided, the adjusting rod (42) being provided in the region between the drive rod (18) and the valve rod (38), one rod coupling (44, 46) coupling the adjusting rod (42) to the drive rod (18), and one rod coupling (44, 46) coupling the adjusting rod (42) to the valve rod (18).

Claims

1-20. (canceled)

21. Actuator (10) for a process plant, comprising an actuating valve (14) and an actuating drive (12) which has an actuating drive housing (20) and a drive rod (18) mounted in the actuating drive housing (20), wherein the actuating drive housing (20) is connected to a valve housing (22) of the actuating valve (14) via a connecting housing, for example a yoke (16), wherein the actuating valve (14) comprising a valve seat (24) and a valve member (36) which interacts with the valve seat (24) and is connected to a valve rod (38) which protrudes into the connecting housing (16), wherein a first rod coupling (44) is provided in order to transfer the driving three between the drive rod (18) and the valve rod (38), and wherein the modular unit composed of the drive rod (18), the valve rod (38) and the first rod coupling (44) is mounted movably relative to the connecting housing (16) via a rotation lock (44d, 50, 52), characterized in that second rod coupling (46) and an adjusting rod (42) are provided, the adjusting rod (42) being provided in the region between the drive rod (18) and the valve rod (38), one rod coupling (44, 46) coupling the adjusting rod (42) to the drive rod (18) and one rod coupling (44, 46) coupling the adjusting rod (42) to the valve rod (18).

22. Actuator according to claim 1, characterized in that the second rod coupling (46) interconnects the drive rod (18) and the adjusting rod (42).

23. Actuator according to claim 1, characterized in that the second rod coupling (46) positively connects the drive rod (18) to the adjusting rod (42) in a direction of the axis (60) of the drive rod (18).

24. Actuator according to claim 1, characterized in that the first rod coupling (44) comprises the rotation lock (44d, 50, 52), which is connected to the connecting housing (16) and allows a drive movement.

25. Actuator according to claim 1, characterized in that the first rod coupling (44) interconnects the adjusting rod (42) and the valve rod (38).

26. Actuator according to claim 25, characterized in that the first rod coupling (44) connects the valve rod (38) to the adjusting rod (42) in a non-positive or positive manner in a direction of the axis (60) ofthe valve rod (38).

27. Actuator according to claim 1, characterized in that the first rod coupling (44) has a length which comprises a minimum contact area for the valve rod (38) with the first rod coupling (44), which is necessary for the non-positive connection, the minimum contact area for the adjusting rod (42) with the first rod coupling (44), and the maximun compensation range for a plurality of different actuating valves (14) and/or the maximum adjustment range for adjusting the stroke of the valve member (36) of the actuating valve

28. Actuator according to claim 1, characterized in that the valve rod (38) has an external thread at its free end that is associated with the first rod coupling (44), the first rod coupling (44) having an internal thread associated with the external thread of the valve rod (38), so that a fine adjustment of the distance of the valve rod (38) with respect to the adjusting rod (42) can be made in the first rod coupling (44).

29. Actuator according to claim 1, characterized in that the adjusting rod (42) has an external thread at its free end that is associated with the first rod coupling (44), the first rod coupling (44) having an internal thread associated with the external thread of the adjust-ing rod (42), so that fine adjustment of the distance of the adjusting rod (42) with respect to the valve rod (38) can be made in the first rod coupling (44).

30. Actuator according to claim 1, characterized in that the adjusting rod (42) has at its free end that is associated with the second rod coupling (46), an outer contour which, interacting with the inner contour of the second rod coupling (46) adapted thereto, results in a form fit in the axial direction of the adjusting rod (42).

31. Actuator according claim 29, characterized in that the adjusting rod (42) has a wrenching flat (42a) between the external thread and the external contour for engagement by a wrenching tool so as to enable rotation of the adjusting rod (42.) by means of the wrenching tool engaging the wrenching flat (42a).

32. Actuator according to claim 1, characterized in that the first rod coupling (44) comprises two half shells (44a, 44b) screwed together and embracing the free ends of the adjusting rod (42) and the valve rod (38).

33. Actuator according to claim 32, characterized in that the drive rod (18), the adjusting rod (42) and the valve rod (38) are arranged concentrically to each other and to a drive axis (60), wherein the half shells (44a, 44b) rest against each other in a plane that extends through the drive axis (60).

34. Actuator according to claim 1, characterized in that the rotation lock engages in a rail (50) on the connecting housing (16) which extends parallel to the drive rod (18).

35. Actuator according to claim 1, characterized in that the rotation lock has releasably arranged sliding shoes, which are designed in particular as sliding bolts (52), via which the rotation lock rests against the connecting housing (16) and is supported thereon and which enables it to slide along the connecting housing (16) in contact therewith during a stroke movement of the drive rod (18).

36. Actuator according to claim 35, characterized in that the sliding shoes (52) are made of plastic.

37. System of an actuator according to claim 1, having a plurality of actuating drives (12) ardor actuating valves (14) and having a plurality of adjusting rods (42), each being of a different length, which enables a method for adjusting a stroke of a valve member (36) of a actuating valve (14), in that by selecting the actuating drive (12) and/or the actuating valve (14) and the appropriate length of the adjusting rod (42), a first rough compensation of the distance between the drive rod (18) and the valve rod (38) is made.

38. System according to claim 37, characterized in that a second fine adjustment is made by turning the adjusting rod (42) with its external thread relative to the internal thread of the first rod coupling (44).

39. System according to claim 37, characterized in that the second fine adjustment is made by turning the valve rod (38) with its external thread relative to the internal thread of the first rod coupling (44).

40. System according to claim 37, characterized in that the second tine adjustment is made by arranging the valve rod (38) and the adjusting rod (42) relative to one another in the first rod coupling (44) and subsequently clamping the first rod coupling (44).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In the drawings,

[0040] FIG. 1 is a lateral view of the actuator according to the invention with an actuating drive, a connecting housing and an actuating valve, the actuating housing being shown in longitudinal section except for its upper portion;

[0041] FIG. 2 is a front perspective view of the ready-to-use connecting housing including a drive rod, an adjusting rod and a valve rod as well as first and second rod couplings;

[0042] FIG. 3 is a front perspective view, taken from the side, of the connecting housing without the drive rod, without the second rod coupling, with the adjusting rod and the valve rod, with the first rod coupling shown in exploded view, and

[0043] FIG. 4 is a front view of the drive housing ready for operation.

DESCRIPTION OF THE INVENTION

[0044] Figures 1 to 4 are views of an embodiment of an actuator 10 according to the invention. The actuator 10 essentially comprises a pneumatic actuating drive 12, an actuating valve 14, and a connecting housing in the form of a yoke 16.

[0045] The actuating drive 12 includes an actuating drive housing 20, the interior of which is separated into a working chamber and a reset chamber by a support plate-diaphragm arrangement. The actuating drive housing 20 is provided with a pneumatic input port, not shown here, through which a loading pressure can be applied to the working chamber. The working chamber is fluid-tightly separated from the reset chamber via the support plate-diaphragm arrangement. Return springs are arranged in the reset chamber. The loading pressure moves the support plate-diaphragm arrangement in one direction against the force of the return springs and, when the loading pressure decreases, it is moved in the other direction by the force of the return springs. The actuating drive 12 is a conventional actuating drive. Therefore, the individual parts of the actuating drive 12 mentioned above are not shown in detail.

[0046] A drive rod 18 is attached to the support plate-diaphragm arrangement. The support plate-diaphragm arrangement is provided with a stop that limits upward axial movement of the drive rod 18. The drive rod 18 extends through the reset chamber, through the lower wall of the actuating drive housing 20, and with its valve end extending vertically into the yoke 16.

[0047] The actuating valve 14 includes an actuating valve housing 22 having a valve seat 24 disposed within the actuating valve housing 22. The actuating valve housing 22 is provided with an inlet port 26 through which process fluid enters the actuating valve housing 22, and with an outlet port 28 through which process fluid exits the actuating valve housing 22. The inlet opening 26 and the outlet opening 28 are each surrounded by a flange 30, 32 in order to connect the actuating valve housing 22 in a known manner to an inlet pipe (not shown here) and an outlet pipe (not shown here), and thus to integrate it into a pipe system. A fluid passage 34 for the process fluid extends in the actuating valve 14 from the inlet port 26 through the valve seat 24 to the outlet port 28.

[0048] Cooperating with the valve seat 24 is a valve member 36 connected to a valve rod 38. The valve rod 38 is aligned vertically, in axial alignment with the drive rod 18. At the end of the valve rod 22 facing away from the drive rod 18, the valve rod 22 is connected to the valve member 36. The valve seat 24 defines a valve opening. Via the valve member 36, the valve seat 24 is closed or more or less released as required. The position of the valve member 36 relative to the valve seat 24 adjusts, for example, a flow rate of the process fluid through the actuating valve 14, or, when the valve member 36 rests on the valve seat 24, altogether prevents the flow of the process fluid through the actuating valve 14.

[0049] A guide sleeve 40 is provided in the actuating valve body 22 for guiding the valve rod 38, as well as a seal packing (not shown).

[0050] An adjusting rod 42 is arranged between the valve rod 38 and the drive rod 18 so as to be coaxial with the valve rod 38 and the drive rod 18. The valve-side end of the adjusting rod 42 and the drive-side end of the valve rod 38 are connected to one another via a first rod coupling 44.

[0051] The adjusting rod 42 extends beyond the first rod coupling 44 in the direction of the drive rod 18. The drive-side end of the adjusting rod 42 and the valve-side end of the drive rod 18 are connected to one another via a second rod coupling 46.

[0052] In the region associated with the first rod coupling 44, the valve rod 38 and the adjusting rod 42 have the same diameter. The first rod coupling 44 comprises two half shells 44a and 44b, each having a cylindrical inner contour 44c that is adapted to the cylindrical outer contour of the valve rod 38 and the adjusting rod 42 in the associated region.

[0053] The two half shells 44a and 44b are connected to one another by screws 48 in such a way that the adjusting rod 42 and the valve rod 38 are non-positively fixed relative to one another in the axial direction at a predetermined distance from each other.

[0054] The first rod coupling 44 has a length consisting of a minimum contact surface of the valve rod 38 with the inner contour 44c necessary for the non-positive connection, a minimum length necessary for a threaded connection between the first rod coupling 44 and the adjusting rod 42, and the maximum compensation range for several different actuating valves 14 and the maximum adjustment range for adjusting the stroke of the valve member 36 of the actuating valve 14.

[0055] On its one side, the yoke 16 is provided with a guide rail 50 aligned parallel to the longitudinal extent of the yoke 16 and thus to the direction of movement of the actuating drive 12. The half shell 44a and the half shell 44b engage the guide rails 50 at their front and rear sides. For this purpose, the half shells 44a, 44b are provided with a guide leg 44d. Each guide leg 44d extends parallel to the guide rail 50 and is provided with sliding bolts 52 on the inside.

[0056] The sliding bolts 52 and the guide rail 50 are matched to one another in terms of material. There is permanent contact between them. Selecting matching materials enables a sliding action with as little frictional resistance as possible during operation of the actuator 10. For this purpose, the guide rail 50 is made of cast steel and the sliding bolts 52 are made of plastic.

[0057] Through its guide leg 44d with the sliding bolts 52, in cooperation with the guide rail 50, the first rod coupling 44 thus serves as a rotation lock for the valve rod 38 which is firmly connected to the first rod coupling 44.

[0058] The adjusting rod 42 is provided with an external thread 42c in the area associated with the first rod coupling 44, and the first rod coupling 44 is provided with an internal thread in the internal contour 44c in the area associated with the adjusting rod 42. This thus allows the distance between the valve rod 38 and the adjusting rod 42, and hence the stroke, to be further adjusted in the assembled state. For this purpose, the adjusting rod 42 has wrenching fiats 42a in the region of the adjusting rod 42 that protrudes from the first rod coupling 44. A wrenching tool can engage the wrenching flats 42a and turn the adjusting rod 42 relative to the first rod coupling 44 via the thread, thus changing the distance to the valve rod 38. In addition, the valve rod 38 may also be provided with an external thread 38a, and with an internal thread in the region of the first rod coupling 44 associated with the valve rod 38, as is illustrated in FIG. 4.

[0059] The region of the adjusting rod 42 associated with the second rod coupling 46 is of a stepped design, which is terminated by a retaining head 42b on the drive rod side. The end of the drive rod 18 on the valve rod side is of a corresponding mirror-inverted design. The inner contour of the second rod coupling 46 is designed to match this so that a backlash-free form fit is achieved.

[0060] The second rod coupling 46 also consists of two half shells that are connected to each other by screws 54. The second rod coupling 46 extends laterally on the outside to a point which serves as a pointer 56. A marking 58 is provided laterally on the inside of the yoke 16. The position of the pointer 56 relative to the marking 58 can be used to read the position of the valve member 36 relative to the valve seat 24, and thus the stroke. The second rod coupling 46 may also include mechanical stroke sensing means adapted to be coupled to a positioner or to a stroke indicator in order to output an actuating signal pro-portional to the stroke value.

[0061] The first rod coupling 44 and the second rod coupling 46 each comprise two half shells. The drive rod 18, the adjusting rod 42 and the valve rod 38 are arranged concentrically to one another and to a drive axis 60. The half shells each rest against each other in a plane that passes through the drive axis 60,

[0062] A set of adjusting rods 42 of different lengths is available for adjusting the stroke of the actuator 10 for an actuating valve 14 selected from several actuating valves of different sizes. Selecting a suitable length of an adjusting rod 42 allows an initial rough adjustment of the compensation of the distance between the valve rod 38 and the drive rod 18 as well as an adjustment of the desired stroke. A further possibility for adjustment is provided by the arrangement of the valve rod 38 relative to the first rod coupling 44 over the clamping range as the range in which a clamping/non-positive connection of the first rod coupling 44 and the valve rod 38 is possible.

[0063] Fine adjustment can then be made by rotating the adjusting rod 42 relative to the first rod coupling 44 using a tool wrench and the thread 42c.

[0064] The invention is thus characterized by providing various possibilities of an adjustment or compensation of the different spacing between a valve rod 38 and the drive rod 18 When different actuating valves 14 are connected for an actuating drive 12 with a predetermined yoke 16.

[0065] List of Reference Signs [0066] 10 actuator [0067] 12 actuating drive [0068] 14 actuating valve [0069] 16 yoke [0070] 18 drive rod [0071] 20 actuating drive housing [0072] 22 actuating valve body [0073] 24 valve seat [0074] 26 inlet port of actuating valve housing 20 [0075] 28 outlet port of actuating valve housing 20 [0076] 30 flange at inlet port 26 [0077] 32 flange at outlet port 28 [0078] 34 fluid passage of actuating valve housing 20 [0079] 36 valve member [0080] 38 valve rod [0081] 38a external thread of valve rod 38 [0082] 40 guide sleeve [0083] 42 adjusting rod [0084] 42a wrenching flat for adjusting rod 42 [0085] 42b retaining head of adjusting rod 42 [0086] 42c external thread of adjusting rod 42 [0087] 44 first rod coupling [0088] 44a half shell of first rod coupling 44-front [0089] 44b half shell of first rod coupling 44-rear [0090] 44c inner contour of first rod coupling 44 [0091] 44d guide leg of first rod coupling 44 [0092] 46 second rod coupling [0093] 48 screws of first rod coupling 44 [0094] 50 guide rail [0095] 52 sliding bolt of first rod coupling 44 [0096] 54 screws of second rod coupling 46 [0097] 56 tip, pointer of second rod coupling 46