Valve Actuators

Abstract

Disclosed herein is an actuator for a valve, comprising: a main shaft extending along an axial centerline of the main shaft and having an opening for receiving a valve stem; a first planetary gear system including a plurality of planetary gears, a first sun gear, and a first ring gear configured to rotate the main shaft about the axial centerline; and a motor for rotating the first planetary gear system, wherein the axial centerline of the main shaft coincides with the central axis of the sun gear of the planetary gear system.

Description

Technical Field

[0001] The present invention relates to an actuator for a valve, and in particular to an actuator having a central opening for receiving a valve stem of a gate valve, a globe valve, or a similar object operated by a stem.

Background Art

[0002] Valves are used to control the flow of fluid in pipes. Valves are normally operated manually, often by a handle, handwheel or plug. Examples include plugs for turning water on and off in showers and kitchen sinks.

[0003] However, there is an increasing demand for actuators that enable operation of valves from remote locations. This is useful, for example, when a captain wants to adjust the ballast water on a ship but does not want to send a crew member into the engine room to open or close the valve. Hydraulic, pneumatic, and electric actuators are used for this purpose. For economic and environmental reasons, electric actuators are taking market share from hydraulic and pneumatic actuators.

[0004] An actuator generally consists of a motor and a gear system. To attach the actuator to the valve, the handwheel of the valve is removed, and the output shaft of the actuator is attached to the valve shaft. The valve shaft is referred to as a valve spindle (for butterfly valves and ball valves) or a valve stem (for globe valves and gate valves). The actuator is controlled by a microcontroller that receives commands via a signal cable and drives the motor to an open position, a closed position, or an intermediate position based on the received commands. After operation, the controller reports operation completion or an error to the main system.

[0005] There are many types and sizes of valves. Some valves, such as butterfly valves and ball valves, are opened and closed by turning a valve spindle attached to the valve's moving part a quarter turn. Other valves, such as globe valves and gate valves, have a stem that moves the valve's moving part up and down.

[0006] Both globe valves and gate valves typically have a stem, part of which is a threaded rod. The main difference between globe valves and gate valves relates to the design of the actuator for these valves. The stem of the globe valve rotates and moves up and down with the handwheel because the stem is screwed in from above and below via a nut that is usually part of the globe valve housing. The stem of a gate valve typically does not rotate. The handwheel is attached to a nut and thrust bearing, allowing the stem to be screwed in from above or below.

[0007] Because the spindle does not move up and down, it is relatively easy to configure an electric actuator capable of operating butterfly valves and ball valves. An example of an actuator made for this purpose is the Eltorque QT250 actuator. This type is not suitable for globe valves or gate valves because the stem cannot move up and down. Disclosure of the latest technologies

[0008] AUMA Riester GmbH&CO.KG manufactures actuators capable of operating gate valves. These actuators feature a gear wheel driven by a worm wheel mounted on the main shaft of an electric actuator, instead of the handwheel of a manual actuator. The motor and gear system of this type of actuator are positioned perpendicular to the stem.

[0009] In AUMA actuators, the stem nut is integrated into the actuator, and this component is rotated by a gear system. To operate the gate valve, the stem nut is threaded, thereby translating the threaded valve stem as it rotates. The valve actuator resulting from this design is not particularly small.

[0010] US2013140476A1 discloses a rotary valve adapter assembly comprising an adapter plate configured to be attached to a rotary valve body.

[0011] No. 20200052A1 discloses an induction valve drive mechanism that minimizes the overall volume of the induction valve drive mechanism while maintaining a large output torque.

[0012] US2011275477A1 discloses a planetary gear reducer including a gear bracket having a central hole and first, second, and third positioning parts arranged parallel to the central hole.

[0013] US2007191177A1 discloses an automatic gear ratio switching device comprising an input carrier, an output carrier, and an intermediate carrier.

[0014] US11118658B1 discloses a planetary gear system and method relating to a flow control actuator for providing a selectable torque and speed range.

[0015] CN114233916A discloses a marine intelligent miniature electric actuation mechanism comprising a motor, an output shaft, and a planetary gear unit.

[0016] EP3109526A1 "Motor-driven valve" discloses a motor-driven valve having a simple configuration that can eliminate hysteresis that occurs when the direction of rotation changes, without significantly modifying conventional motor-driven valves.

[0017] CN210566567U, "Power-off self-locking valve electric actuating device," discloses a power-off self-locking valve electric actuating device. This valve comprises a valve body to which a fixed sleeve is attached. A valve plate is fixed between the fixed sleeve and the valve body, a valve rod is fixed on top of the fixed sleeve, and the valve plate is attached to the bottom of the valve rod via a threaded structure. [Overview of the project] [Problems that the invention aims to solve]

[0018] The object of the present invention is to provide an actuator for a stemmed valve. The main problem that the present invention seeks to solve is a method for manufacturing a miniature actuator for globe valves, gate valves, or other stemmed valves. The advantage that the present invention has over the prior art is its miniaturization. [Means for solving the problem]

[0019] According to a first aspect of the present invention, a valve actuator is provided comprising a main shaft having an opening extending along the axial centerline of the main shaft for receiving a valve stem; a first planetary gear system including a plurality of planetary gears, a first sun gear, and a first ring gear, configured to rotate the main shaft about its axial centerline; and a motor for rotating the first planetary gear system, wherein the axial centerline of the main shaft coincides with the axis of the sun gear of the planetary gear system.

[0020] As used herein, the term "valve actuator" refers to a device that can be attached to a valve and can open or close the valve upon receiving a signal to open or close the valve.

[0021] The reference to the first planetary gear system being configured to rotate the main shaft around its axial centerline means that the gear system is arranged to be coupled to the main shaft such that when the planetary gear system rotates or acts, it rotates the main shaft. The coupling between the main shaft and the first planetary gear system does not necessarily have to be direct, and there may be one or more additional gear systems or other mechanisms arranged to couple the first planetary gear system to the main shaft.

[0022] In an embodiment, the first sun gear and / or the first ring gear is arranged in the actuator so as to surround the main shaft and the opening thereof, and in use, the valve stem can translate up and down along the rotation axis of the first sun gear and / or the first ring gear, and the shaft extends through the central opening of the first sun gear and / or the ring gear. A bearing may be provided between the first sun gear and the main shaft to allow the first sun gear to rotate about the main shaft. The first ring gear may be manufactured as a part of the actuator housing, or may be manufactured as a separate component that is fixedly mounted within said housing.

[0023] In an embodiment, the actuator comprises a hollow valve nut coupled to the main shaft, having a center line coinciding with the axial center line of the main shaft, and provided with a through hole through which the valve stem extends in use, the inner surface of the through hole is formed to interact with the valve stem, and translates the valve stem along the axial center line of the shaft when the main shaft rotates. The valve nut may be coupled to the main shaft so as to rotate together with the main shaft.

[0024] In an embodiment, the valve nut is configured to be detachably connected to the main shaft. In this way, the actuator can be easily adapted to work with valves of various types / sizes. In an embodiment, the valve nut and the main shaft are formed as one integral part. The valve nut and the shaft may for example be machined from the same piece of material, or molded as one piece. The detachable connection may for example be achieved by one or more screws that can be removed to replace the valve nut.

[0025] In an embodiment, the motor for rotating the first planetary gear system is an electric motor.

[0026] In an embodiment, the actuator is rotatable about the axial centerline of the main shaft, and comprises a rotor frame coupled to the main shaft via a first planetary gear system. In an embodiment, the rotor frame is hollow and surrounds the main shaft. Accordingly, the main shaft extends through the center of the rotor frame. This reduces the installation footprint of the actuator, allowing a compact design.

[0027] In an embodiment, the actuator comprises a locking mechanism including a locking element that is movable between a locked position, in which the locking element is pressed against the main shaft or a lock ring fixed to the main shaft to prevent rotation of the main shaft, and an unlocked position, in which the main shaft can rotate relative to the locking element. In the unlocked position, the locking element is not pressed against the main shaft or the lock ring, so movement of the main shaft is not impeded. The novel feature of this embodiment is that the locking mechanism locks against the main shaft instead of the housing of the actuator. This again provides a particularly compact configuration of the entire mechanism.

[0028] In an embodiment, the locking mechanism comprises at least one unlocking pin coupled to the rotor frame for moving the locking element from the locked position to the unlocked position when the rotor frame rotates in either direction about the axial centerline of the main shaft. The use of an unlocking pin coupled to the rotor in this manner means that (intended) rotation of the shaft by the rotor frame is not impeded, while rotation of the shaft by other means is prevented. Accordingly, undesired actuation of the valve is prevented.

[0029] In embodiments, the actuator comprises a second planetary gear system including a second plurality of planetary gears, a second sun gear, and a second ring gear, the second planetary gear system being arranged to couple the first planetary gear system to the main shaft and rotate the main shaft around its axial centerline. The second planetary gear system may have the same structure as the first planetary gear system and may be arranged to surround the shaft. The second planetary gear system is typically located above (further from the valve nut) the first planetary gear system. In embodiments, one or more planetary gear systems similar to the second planetary gear system may be added on top of the second planetary gear system, if desired. Since each planetary gear system has a gear ratio and the system as a whole requires a certain total gear ratio, the number of planetary gear systems depends on specific design requirements, and the ratios of the individual systems are multiplied to obtain the total gear ratio. Thus, the addition of one or more additional planetary gear systems increases the flexibility of the actuator in terms of feasible gear ratios.

[0030] In an embodiment, the actuator comprises a first split annular gear system including a lower annular sun gear, a plurality of lower annular planetary gears, a plurality of upper annular planetary gears, an annular gear carrier, and an upper annular sun gear, the upper annular sun gear being arranged to rotate with the main shaft. In an embodiment, the first annular gear system is configured to reverse the direction of rotation of the main shaft. This can be achieved by the upper annular sun gear having more teeth than the lower annular sun gear. Thus, in an embodiment, the number of teeth on the upper annular sun gear is greater than the number of teeth on the lower annular sun gear. The advantage of including this split annular gear system is that the gear ratio can be potentially higher than that of a planetary gear system, and the need for a plurality of planetary gear systems can be reduced. Furthermore, if the annular gear system is also configured to reverse the direction of rotation, the emergency operating wheel has the same direction of rotation as the valve stem or nut, making manual operation of the valve more intuitive.

[0031] In one embodiment, the hollow valve nut is provided with a female thread that allows the threaded valve stem to freely translate upward along the centerline of the main shaft as the main shaft rotates. This configuration is suitable for gate valves and other valves where it is undesirable for the stem to rotate when translating axially along the main shaft. The female thread refers to the threads located on the surface of the valve nut through-hole, which is the inward-facing surface toward the central axis.

[0032] In embodiments, the through-hole of the valve nut has a non-circular cross-section, allowing a valve stem having a similar cross-section to freely translate upward along the centerline of the main shaft as the main shaft rotates. This configuration is suitable for globe valves and other valves where rotation of the stem is acceptable as it translates axially along the main shaft. Furthermore, the cross-sectional shape of the valve nut hole may have a non-circular shape, such as a square, triangle, ellipse, rectangle, pentagon, hexagon, or other polygon.

[0033] In embodiments, the rotor frame is the frame of the rotor of an electric motor and is configured to rotate about the axial centerline of the main shaft. The motor, including the rotor frame, is configured to rotate the main shaft around its axial centerline. The rotor may have a magnetic, squirrel-cage, or other shape that allows interaction between the magnet and the stator. The stator may surround the rotor frame. In embodiments, the motor is configured to rotate the main shaft by transmitting torque through a bottom emergency shaft and the rotor frame to rotate the main shaft. In this configuration, the motor is mounted outside the actuator housing and may be a "commercially available" electric, hydraulic, or pneumatic motor.

[0034] In one embodiment, the actuator includes an encoder, which is mounted on the main shaft and comprises an encoder gear device configured to count the number of rotations of the main shaft. The encoder gear device may optionally rotate the encoder shaft via a set of encoder gears such that the encoder shaft rotates once for every integer rotations (generally two or more rotations, preferably 15 to 40 rotations, most preferably 30 rotations) of the main shaft. By counting the number of rotations of the main shaft, the position of the valve can be monitored. The relative number of rotations can be precisely adjusted as desired.

[0035] Next, embodiments of the present invention will be described simply as illustrative examples with reference to the following drawings. [Brief explanation of the drawing]

[0036] [Figure 1] The diagram shows a cross-sectional view of the entire actuator, as well as isometric views from above and below. [Figure 2] The first assembly step involves attaching the bottom of the actuator and the first planetary gear system. [Figure 3] This shows the second assembly step of installing the second planetary gear system. [Figure 4] The third assembly step involves installing the split annular gear. [Figure 5] The fourth assembly step, which involves installing the automatic locking mechanism, is shown. [Figure 6] The fifth assembly step shows the installation of the rotor and stator of the electric motor for operating the actuator. [Figure 7] The sixth assembly step shows the installation of the emergency handle and encoder gear mechanism. In the diagram, most of the parts are hidden, so the plate to which these parts are normally mounted is concealed. [Figure 8] This shows the same thing as in Figure 7, but without showing the hidden parts. [Figure 9] This indicates the main shaft. [Figure 10]The first solar gear for the first planetary gear system is shown. [Figure 11] This shows the carrier for the planetary gears in a multi-stage planetary gear system. [Figure 12] This shows a cross-sectional view of the upper planetary gear of a multi-stage planetary gear system. [Figure 13] Figure 1 shows a cross-sectional view of the automatic locking mechanism. [Figure 14] This shows the rotor inside the motor. [Figure 15] This shows the emergency mechanism separated into two parts. [Modes for carrying out the invention]

[0037] Figures 1–8 include cross-sectional views and at least one isometric view of the same assembly step. The remaining figures show important or partially obscured parts in Figures 1–8.

[0038] The lower part of Figure 1 shows a valve nut (40) suitable for operating a gate valve. Since the valve nut (40) is a nut that moves the stem of the gate valve up and down, it needs to be machined to fit the threads of the stem. The valve nut can be fixed to the main shaft (2) with a bolt (47), making it easy to replace. When the actuator operates a globe valve, the threads (40A) of the valve nut (40) are replaced with a hole having a non-circular cross-section. The hole may have the same dimensions as the opening (51) that extends axially through the main shaft (2). The cross-section of the hole may be any non-circular shape, such as a square, triangle, ellipse, rectangle, pentagon, or hexagon. It is preferable to include a shape with three or more corners to help prevent slippage. A particularly advantageous shape for the cross-section of the valve nut opening is a hexagon. If the actuator is intended only to operate a globe valve, the cross-section of the central opening of the valve nut (40) and the cross-section of the valve stem should preferably have the same shape and fit well together. If the actuator is intended solely for operating a gate valve, the opening (51) in the main shaft (2) may be the same size and shape as the central opening of the valve nut (40), or it may be replaced with a round opening (51) which is much easier to machine. Figure 1 shows a hexagonal opening (51) in the main shaft (2), where the opening (51) is large enough to accommodate a threaded stem when operating a gate valve, and the same size as the hole in the valve nut when operating a globe valve, so that the actuator can operate both globe valves and gate valves with only minor adjustments. A seal (39) at the bottom of the main shaft prevents water and debris from entering the actuator. The valve nut (40) and the main shaft (2) rotate within the actuator bottom (1). For mounting the actuator to the valve, the actuator bottom (1) has a threaded hole (1A). Bearings (43, 44) ensure that the main shaft rotates smoothly. Any suitable coupling means may be used to couple the valve nut to the stem. Furthermore, the valve nut (40) and the main shaft (2) can also be constructed as a single component.The advantages of this design are that it reduces the number of actuator parts and that the bottom seal (39) can have the same diameter as the top seal (41). The disadvantage is that the actuator can only fit one type of valve because both the stem diameter and stem thread dimensions must match the type of valve.

[0039] Figure 2 shows the first assembly step. The first ring gear (5) is positioned on top of the actuator base (1). The first ring gear (5) and the actuator base (1) can be manufactured as a single part, but here they are shown as two parts for ease of manufacture. Inside the ring gear (5) is the first planetary gear (4), which has a bearing (4A) and a shaft (4B). The shaft is pressed into a hole (2B) in the main shaft (2) by a press path. These holes (2B) are only visible in Figure 9. The same applies to the bearing path (2A). In the center is the first sun gear (3, 6). The first sun gear consists of two parts (3, 6) joined by a press path. These may be manufactured as a single part. Radial needle bearings (46) and axial needle bearings (44) ensure that the first sun gear (3, 6) rotates smoothly around the main shaft (2). The modulus of the first planetary gear system is 1.5 in the presented figure. The modulus is not fixed and can be changed to a value appropriate to the design parameters according to the specific design.

[0040] Figure 3 shows the second assembly step. A second ring gear (9) having gear teeth (9A) is mounted on top of the first ring gear (5). The second ring gear is smaller to provide space for a large needle bearing (45). Once all the outer parts are bolted together through the holes in the outermost part (49), the large axial needle bearing (45) transmits thrust force between all the parts that together form the housing (1, 5, 9, 16, 17, 22, 23) and the first sun gear (3, 6), and this thrust force is transmitted again to the valve nut (40) through the needle bearing and main shaft (2). Without the large bearing (45), thrust bearings would be required throughout the entire actuator, and including the large bearing (45) simplifies the valve structure, but this is optional. Inside the second ring gear (9) is a second planetary gear (8) having a needle bearing (8A) and a shaft (8B). The shaft is pressed into the holes of the first sun gear (6). These holes (6B) are shown in Figure 10, which shows the upper half of the first sun gear (6). Note also the path (6A) for the large axial needle bearing (45). The second sun gear (7) is joined to the lower sun gear (10) of the split annular gear. The modulus of the second planetary gear system is 1.0 in the presented figure. The modulus is not fixed and can be changed to a value appropriate to the design parameters according to the specific design. If desired, one or more planetary gear systems similar to the second planetary gear system can be added on top of the second planetary gear system.

[0041] Figure 4 shows the third assembly step, where a split annular gear system is added. The reason for including the split annular gear system is to achieve a higher gear ratio compared to a normal planetary gear system at this stage. This is because the sun gear in each step must have a diameter larger than the diameter of the main shaft. For example, in the presented figure, the first planetary sun gear (3) has 64 teeth, and the first planetary ring gear (5) has 104 teeth. This results in a gear ratio of only 2.625. Thus, the three-stage planetary gear system has a gear ratio of only about 18. In a split annular gear system, the gear ratio can be significantly larger. However, the torque transmission capacity of the split annular gear is lower than that of a planetary gear system. Therefore, including a split annular gear system coupled to the main shaft (2) via one or more planetary gear systems is an optional addition, although it has certain advantages.

[0042] The split annular gear system in Figure 4 consists of gears with a modulus of 0.5. The modulus is not fixed and can be changed to a value appropriate to the design parameters according to the specific design. In the presented figure, the lower annular sun gear (10) is the output and has 160 teeth, but various numbers of teeth are possible for different applications. In one example, the lower annular planetary gear (11) has 36 teeth. In this example, the upper annular planetary gear (14) has 32 teeth, but it is clear that different numbers of teeth can be selected for one or both gears depending on the desired operation. The lower annular planetary gear (11) and the upper annular planetary gear (14) are mounted on the same shaft (14A). Since there is a press path between the holes of the planetary gears (11, 14) and the shaft (14A), the planetary gears (11, 14) and the shaft (14A) rotate as a single part. The shaft (14A) is mounted in the hole of the annular gear carrier (12) by needle bearings (12A). The annular gear carrier (12) is shown in Figure 11. The annular gear upper sun gear (13) has 164 teeth in this example, but various numbers of teeth are possible for different applications. The annular gear upper sun gear (13) is mounted to the main shaft (2) by a press path and moves with the main shaft (2). The annular gear upper ring (20A) is part of the lower automatic locking (20) mechanism. The annular gear upper ring (20A) has 228 teeth in this example, but various numbers of teeth are possible for different applications. The annular gear upper ring (20A) is the input to the annular gear. The gear ratio in the annular gear using the presented configuration is approximately 9.3, but various gear ratios are possible for different applications. Since the upper sun gear has more teeth than the lower sun gear, the direction of rotation in the annular gear is opposite. This is desirable because the main shaft (2) rotates in the same direction when the emergency handle (29) is rotated. This also results in a slightly higher overall gear ratio. The upper annular sun gear moves together with the main shaft (2), and the gear ratio is affected by the rotational speed of the main shaft (2), so calculating the gear ratio is not straightforward. Figure 12 shows a cross-sectional view through the annular upper sun gear (13).

[0043] Figure 5 shows the fourth assembly step, in which the automatic locking mechanism is assembled. The purpose of the automatic locking mechanism is to ensure that torque can only be transmitted from the motor to the valve. The automatic locking mechanism prevents torque from being transmitted from the valve to the motor, thereby ensuring that the valve does not move unintentionally. The novelty in this actuator is that the automatic lock locks against the main shaft (2) rather than the housing (1, 5, 9, 16, 17, 22, 23). The reason for this design is that it is efficient and results in a compact, space-saving design, as the automatic locking mechanism can be located inside the motor. In one example, the automatic locking mechanism consists of a bottom automatic lock (20), one or more rollers (20B), one or more release pins (19A), and a lock ring (21). The lock ring (21) has a press path against the main shaft (2), so they rotate together. The rollers (20B) are pressed into the locked position by a spring (20C) shown in the cross-sectional view of Figure 13. When the spring (20C) moves the roller (20B) toward the unlock pin (19A), a locking action is brought about by a machined surface (20D) that presses the roller (20B) against both the auto-locking bottom (20) and the lock ring (21). As the rotor frame (19) rotates, one of the unlock pins (19A) pushes one of the rollers out of the locked position. This allows the rotor frame (19) to rotate in the direction of rotation. The two unlock pins engage in press paths with two holes in the rotor frame (19). The inclusion of two unlock pins and two rollers means that the locking mechanism can function for the rotor frame (19) rotating in either direction.

[0044] Figure 6 shows the fifth assembly step. In this step, the rotor, comprising a rotor frame (19), magnets (18), an optional emergency operation gear wheel (27), and an unlock pin (19A), is mounted on the automatic locking mechanism. In Figure 6, most of the rotor is hidden, and the rotor is also shown in Figure 14. The rotor rotates around the main shaft (2) and is supported by ball bearings (43) and axial thrust needle bearings (44) that roll on a lock ring (21). A stator, comprising laminated iron (17), coil supports (16, 22), and coils (17A), is positioned outside the rotor. An annular gear carrier support (15) provides additional support to the annular gear carrier (12) via a large radius bearing (43). The annular gear carrier support (15) also provides support to the stator, ensuring that the stator is centered on the main shaft (2). The axial centerline of the stator and the axis of rotation of the rotating frame (19) coincide with the axial centerline of the main shaft. In this respect, the entire device is extremely compact. The electric motor may be a three-phase axial flux PM motor with 12 poles and dispersed windings. However, the actuator may be any electric motor of appropriate dimensions. The motor may preferably have a through hole in the center and may be mounted around the main shaft. Thus, all "commercial" motors are excluded.

[0045] It is possible to add a second “emergency shaft” and place a “commercial” motor or another motor on this emergency shaft to drive the actuator, but this solution would be significantly bulkier than the presented design. The motor mounted in this way may be an electric motor, a hydraulic motor, or a pneumatic motor. In this case, magnets (18), coils (17A), laminated steel (17), etc., may not be required. Such an embodiment includes a rotating frame (19), but the rotating frame (19) is rotated via the emergency shaft rather than forming part of the rotor of the motor itself. Even if the rotating frame (19) forms part of the motor, an emergency shaft may be included for use in emergencies when the primary motor fails to function for some reason.

[0046] Figure 7 shows the locations of the emergency shaft and the optional encoder gear unit. This figure is not an assembly step, as many components are not shown in their final assembly positions. The locations of parts hidden by the encoder plate (24) are shown. In Figure 7, the encoder gear wheel (35) is mounted on the main shaft (2). This encoder gear wheel interacts with the encoder gear unit (36) to rotate the encoder shaft (37) within the absolute encoder (38). The encoder gear unit (36) is positioned so that the encoder shaft rotates once for every approximately 30 rotations of the main shaft. This allows the absolute encoder (38) to determine the number of rotations of the main shaft (2) and, consequently, the position of the valve. It is assumed that the total stroke length of the valve is less than 30 rotations so that the absolute encoder (38) fits within one rotation, but these parameters are adjustable. For example, if the actuator is mounted on a valve with a stroke length greater than 30 rotations, the encoder gear unit may be reconfigured.

[0047] Figure 7 shows the shafts and handles for emergency operation of the valve. The lower emergency shaft (25) has a gear wheel (26) that interacts with a gear wheel (27) on top of the motor. Therefore, the lower emergency shaft (25) rotates when the motor rotates the valve. Rotation of the upper emergency shaft (28) and handle (29) during normal operation is undesirable because it would cause rapid wear of the emergency shaft seal (42). Therefore, there is a clutch between the upper emergency shaft (28) and the lower emergency shaft (25).

[0048] The clutch functions as follows: When the emergency operation is not used, the lock wing (34) remains on the lock (31). In this way, the lock wing (34) lifts and holds the emergency shaft (28). When the emergency handle (29) is rotated, the lock wing rotates to a position where it is released from the lock (31). Then, the spring (33) pushes down the upper emergency shaft (28). The edge (28A) of the upper emergency shaft (28) descends into the slot (25A) of the lower emergency shaft (25) as the upper emergency shaft (28) rotates further. Thus, the rotation of the emergency handle (29) rotates the rotating frame (19) and moves the valve. The guide pin (28B) ensures that the upper emergency shaft (28) descends straight down. The nut (30) attaches the lock wing (34) and the emergency handle (29) to the upper emergency shaft (28). The bolt (31A) secures the lock (31) to the top cover (23). Figure 15 shows the emergency shaft in more detail. In Figure 15, the emergency handle (29) and nut (30) are omitted so that the lock wing is visible.

[0049] Figure 8 shows the sixth assembly step. Here, most of the components shown disassembled in Figure 7 are attached to the encoder plate (24), and the edges of the encoder plate (24) are inserted by sliding into the stator. The bearing between the encoder plate (24) and the main shaft (2) is not essential, but it contributes to positioning the laminated iron (17) of the stator around the rotor. The encoder plate (24) functions as a support for the encoder (38), encoder shaft (37), encoder gear mechanism (36), and lower emergency shaft (25).

[0050] Figure 1 shows the seventh and final assembly step to complete the actuator. Here, the top cover (23), top seal (41), emergency shaft seal (42), top emergency shaft (28), top emergency shaft spring (33), emergency handle (29), nut (30), lock wing (34), lock (31), and bearing (34) are mounted on top of the actuator. Wires from the encoder and motor can be routed through the hole (23A) in the top cover (23). Other solutions for routing the wires are also possible. If the actuator is for underwater use, the connections must be IP68 rated.

[0051] After the actuator is attached to the valve, the hole in the central shaft can be filled with grease and a cover can be placed over the hole. This ensures that the valve nut (40) remains lubricated for a very long period of time.

Claims

1. A main shaft (2) having an opening (51) for receiving a valve stem of a gate valve or globe valve, which extends through the main shaft (2) along the axial centerline of the main shaft (2) and is arranged to translate along the axial centerline, A first planetary gear system (3, 4, 5, 6) is configured to rotate the main shaft (2) about an axial centerline, and includes a plurality of planetary gears (4), a first sun gear (3, 6), and a first ring gear (5). A motor for rotating the first planetary gear system, comprising a hollow rotor frame surrounding the main shaft extending through the center of the rotor frame, Equipped with, An actuator for a gate valve or globe valve, wherein the axial center line of the main shaft (2), the central axis of the sun gear of the planetary gear system, and the rotation axis of the rotor frame coincide.

2. A hollow valve nut (40) is connected to the main shaft (2), has an axial centerline that coincides with the axial centerline of the main shaft, and has a through hole through which the valve stem extends during use. An actuator for a gate valve or globe valve according to claim 1, comprising, wherein the inner surface of the through hole is formed to interact with the valve stem, and when the main shaft rotates, it causes the valve stem to translate along the axial centerline of the main shaft (2).

3. The valve nut (40) is configured to be removably connected to the main shaft (2), as described in claim 2, for a gate valve or globe valve actuator.

4. The valve nut (40) and the main shaft (2) are formed as a single integrated part, the actuator for a gate valve or globe valve according to claim 2.

5. The actuator for a gate valve or globe valve according to claim 1, wherein the motor for rotating the first planetary gear system is an electric motor.

6. A rotor frame (19) is rotatable about the axial center line of the main shaft (2) and is coupled to the main shaft (2) via the first planetary gear system (3, 4, 5, 6). An actuator for a gate valve or globe valve according to claim 1, comprising:

7. The actuator for a gate valve or globe valve according to claim 6, wherein the rotor frame (19) is hollow and surrounds the main shaft (2).

8. A locking element (20) is provided to prevent the rotation of the main shaft (2) by allowing it to move between a locked position in which the locking element (20) is pressed against the main shaft (2) or a locking ring (21) fixed to the main shaft (2), and an unlocked position in which the main shaft (2) can rotate relative to the locking element (20). An actuator for a gate valve or globe valve according to claim 1, comprising a locking mechanism including the locking mechanism.

9. The actuator for a gate valve or globe valve according to claim 8, wherein the locking mechanism includes at least one unlocking pin (19A) coupled to the rotor frame (19) to move the locking element (20) from the locked position to the unlocked position when the rotor frame (19) rotates in any direction about the axial center line of the main shaft (2).

10. An actuator for a gate valve or globe valve according to claim 1, comprising a second planetary gear system (7, 8, 9) including a second plurality of planetary gears (8), a second sun gear (7), and a second ring gear (9), wherein the planetary gear system (7, 8, 9) is arranged to connect the first planetary gear system (3, 4, 5, 6) to the main shaft and rotate the main shaft (2) around its axial centerline.

11. An actuator for a gate valve or globe valve according to claim 1, comprising a first split annular gear system (10, 11, 12, 13, 14) including a lower annular sun gear (10), a plurality of lower annular planetary gears (11), a plurality of upper annular planetary gears (14), an annular gear carrier (12), and an upper annular sun gear (13), wherein the upper annular sun gear (13) is arranged to rotate together with the main shaft (2).

12. The actuator for a gate valve or globe valve according to claim 11, wherein the annular gear system (10, 11, 12, 13, 14) is configured such that the upper annular sun gear (13) has more teeth than the lower annular sun gear (10) to reverse the direction of rotation of the main shaft (2).

13. The actuator for a gate valve or globe valve according to claim 1, wherein the hollow valve nut (40) has a female thread that allows the threaded valve stem to freely translate upward along the axial centerline of the main shaft (2) when the main shaft (2) rotates.

14. The actuator for a gate valve or globe valve according to claim 1, wherein the through hole of the hollow valve nut (40) has a non-circular cross-section, and as the main shaft (2) rotates, a valve stem having a similar cross-section can freely translate upward along the centerline of the main shaft (2).

15. The rotor frame (19) is the frame of the rotor of the electric motor and is configured to rotate about the axial center line of the main shaft (2), as described in claim 6, for a gate valve or globe valve actuator.

16. The actuator for a gate valve or globe valve according to claim 6, wherein the motor is configured to rotate the main shaft (2) by transmitting torque via the bottom emergency shaft (25) and the rotor frame (19) in order to rotate the main shaft (2).

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