Straight stroke limit switch and control device capable of adapting to different strokes

Abstract

The application relates to a straight stroke limit switch and control device which can be adapted to different strokes. The limit switch comprises: a micro switch assembly, which comprises a full opening position switch and a full closing position switch; a support frame, which is provided with an axially extending opening position sliding groove and a closing position sliding groove, the full opening position switch is adjustably installed at the opening position sliding groove, and the full closing position switch is adjustably installed at the closing position sliding groove; a shell, which is used for installing the support frame and the micro switch assembly; a feedback shaft, which is arranged in the shell and is fixedly connected with an actuator of a valve body, the feedback shaft is provided with a cam assembly, the cam assembly comprises at least one first fixed ring; when the feedback shaft moves to a full opening position of the valve body along with the actuator, the cam assembly triggers the full opening position switch; when the feedback shaft moves to a full closing position of the valve body along with the actuator, the cam assembly triggers the full closing position switch.

Description

Technical Field

[0001] This invention relates to the field of industrial pneumatic valve control components, and more specifically, to a linear limit switch and control device adaptable to different strokes. Background Technology

[0002] In industrial fluid control systems, pneumatic diaphragm valves and pneumatic angle seat valves are the two most widely used types of linear stroke control valves. Valve bodies of different diameters and brands naturally exhibit significant stroke dispersion, and there has never been a unified standardized stroke parameter in the industry.

[0003] Currently, the mainstream general-purpose linear limit switches in the industry generally adopt a factory-preset fixed-stroke rigid triggering structure, which has the following defects: First, the cross-category compatibility is poor. The installation position and effective length of the trigger arm of the micro switch are fixed parameters that cannot be adjusted. It can only be adapted to a single valve body with a specific stroke and cannot cover the differentiated stroke requirements of two types of valves. The on-site spare parts inventory is diverse and the management cost is high. On-site debugging relies entirely on manual grinding of the cam assembly and repeated loosening and tightening of screws to adjust the switch position. The efficiency of adapting and debugging a single valve is extremely low.

[0004] Meanwhile, the rubber diaphragm of the diaphragm valve will deform and extend due to repeated bending over a long period of time, and the piston seal of the angle seat valve will wear and move over a long period of time. The unique structural characteristics of these two types of valves will cause continuous stroke drift. Traditional fixed structure limit switches cannot compensate for this kind of operating error. After long-term use, the switch position triggering deviation is very likely to occur. This can lead to internal leakage of the valve and abnormal wear of the sealing surface, or even overload and burnout of the actuator. In high-requirement scenarios such as food, medicine and fine chemicals, it may even cause production safety accidents.

[0005] Therefore, there is an urgent need to provide a linear limit switch that can adapt to different actual strokes and adjust and compensate for stroke drift, so as to meet the position detection requirements of linear valves such as diaphragm valves and angle seat valves. Summary of the Invention

[0006] The technical problem to be solved by the present invention is that existing limit switches cannot simultaneously meet the requirements of different strokes. In view of the above-mentioned defects of the prior art, a linear limit switch and control device that can be adapted to different strokes is proposed.

[0007] The technical solution adopted by this invention to solve its technical problem is: to propose a linear limit switch that can be adapted to different strokes, comprising: The micro switch assembly includes: a fully open switch and a fully closed switch; The support frame is provided with an axially extending open position slide groove and a closed position slide groove. The fully open position switch is adjustablely installed in the open position slide groove, and the fully closed position switch is adjustablely installed in the closed position slide groove. Housing for mounting the support frame and the micro switch assembly; A feedback shaft is disposed within the housing and fixedly connected to the actuator of the valve body. A cam assembly is provided on the feedback shaft, and the cam assembly includes at least one first fixed ring. When the feedback shaft moves with the actuator to the fully open position of the valve body, the cam assembly triggers the fully open position switch; when the feedback shaft moves with the actuator to the fully closed position of the valve body, the cam assembly triggers the fully closed position switch.

[0008] In some embodiments, the support frame includes a first switch base and a second switch base, the first switch base and the second switch base are arranged perpendicularly to each other, the open position slide groove is disposed on the first switch base, and the closed position slide groove is disposed on the second switch base.

[0009] In some embodiments, the open position slide groove includes two parallel open position slide grooves disposed on the first switch base, and the close position slide groove includes two parallel close position slide grooves disposed on the second switch base. The fully open switch is installed between the two open position slides, and the fully closed switch is installed between the two closed position slides.

[0010] In some embodiments, after the axial position adjustment is completed, the fully open switch and the fully closed switch are respectively fixed to the first switch base and the second switch base by fixing pins or fixing screws and nuts.

[0011] In some embodiments, the upper end of the inner side of the fully open switch is provided with an open contact, and the lower end of the inner side of the fully closed switch is provided with a closed contact. The triggering directions of the open contact and the close contact are perpendicular to each other, and the actuating ends of the open contact and the close contact are both oriented toward the feedback shaft.

[0012] In some embodiments, the cam assembly includes only the first retaining ring; The first retaining ring moves axially with the feedback shaft and contacts the open contact when the feedback shaft moves to the fully open position of the valve body, and contacts the closed contact when the feedback shaft moves to the fully closed position of the valve body.

[0013] In some embodiments, the cam assembly further includes a second retaining ring, wherein the first retaining ring and the second retaining ring are spaced apart along the axial direction of the feedback shaft; The first retaining ring is used to trigger the fully open position switch when the feedback shaft moves to the fully open position of the valve body, and the second retaining ring is used to trigger the fully closed position switch when the feedback shaft moves to the fully closed position of the valve body; The axial spacing between the first fixed ring and the second fixed ring constitutes the stroke compensation distance, and the actual detection distance between the open contact and the closed contact is equal to the sum of the actual movement stroke of the valve body actuator and the stroke compensation distance.

[0014] In some embodiments, the feedback shaft is provided with a plurality of mounting holes spaced apart along its axial direction, and both the first fixing ring and the second fixing ring are provided with fixing holes corresponding to the mounting holes; The first retaining ring and the second retaining ring are fixed to the feedback shaft by means of retaining pins passing through corresponding retaining holes and selected assembly holes, respectively, so as to adjust the stroke compensation distance.

[0015] In some embodiments, the limit switch further includes a terminal assembly, the terminal assembly including two terminal blocks fixedly disposed inside the housing; The terminal assembly is electrically connected to the fully open switch and the fully closed switch respectively, and is used to connect to an external control system to output a fully open signal and a fully closed signal for the valve body.

[0016] The present invention also provides a control device, including a valve body, an external control system, and a linear limit switch adaptable to different strokes as described in any of the above. The feedback shaft of the limit switch is connected to the actuator of the valve body, and the terminal assembly of the limit switch is connected to the external control system. The external control system is used to receive the fully open signal output by the fully open switch and the fully closed signal output by the fully closed switch, so as to monitor the open and closed status of the valve body. The external control system is equipped with a valve position abnormality judgment logic module. When only a fully open signal or only a fully closed signal is received, the valve position jamming alarm is automatically triggered. The external control system has a reserved low-power wireless communication interface, which can be connected to a LoRa wireless transmission module to synchronously upload the valve position status signal to the remote operation and maintenance platform.

[0017] Implementing this invention has at least the following beneficial effects: By setting open and closed position slide grooves on the support frame, the fully open and fully closed switches can be adjusted along the axial direction of the feedback shaft, thereby adjusting the detection distance between the two contacts to adapt to linear stroke valve bodies with different actual strokes; by setting a single fixed ring or a first and second fixed ring spaced axially on the feedback shaft, for valve bodies with larger strokes, the single fixed ring can be used to complete the fully open and fully closed triggering, and for valve bodies with smaller strokes, the stroke compensation distance between the two fixed rings can be used to achieve the corresponding triggering, thereby achieving position detection while maintaining the installation and adjustment space of the switch; by fixing the fixed ring to the selected mounting hole of the feedback shaft and fixing it after the switch position is adjusted, it is beneficial to improve the repeatability stability of the trigger position and reduce the possibility of deviation in the open and closed position detection caused by valve body stroke differences or long-term operation. Attached Figure Description

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings: Figure 1 This is a schematic diagram of the overall structure of the linear limit switch that can be adapted to different strokes provided by the present invention; Figure 2 yes Figure 1 The sectional view shown is along line AA. Figure 3 This is a schematic diagram of the internal structure of the linear limit switch that can be adapted to different strokes provided by the present invention; Figure 4 This is a schematic diagram of the assembly structure of the feedback shaft, the first fixing ring, and the second fixing ring provided by the present invention. Figure 5 This is an exploded structural diagram of the feedback shaft, the first fixing ring, and the second fixing ring provided by the present invention. Figure 6 This is a schematic diagram of the cooperative structure of the support frame, micro switch assembly, feedback shaft and cam assembly provided by the present invention; Figure 7 This is a three-dimensional structural diagram of the bottom shell provided by the present invention; Figure 8 This is a three-dimensional structural diagram of the support frame provided by the present invention; Figure 9 This is a schematic diagram of the assembly structure of the support frame and micro switch assembly provided by the present invention; Figure 10 This is a schematic diagram of the control device provided by the present invention; Figure 11 This is a block diagram showing the structure and signal connection of the control device provided by the present invention.

[0019] Explanation of icon numbers: Housing 100, bottom housing 110, lower bearing 111, first mounting base 112, second mounting base 113, front housing 120, upper bearing 121, transparent cover plate 130, range extender copper sleeve 140. Support frame 200, first switch base 210, second switch base 220, open position slide 201, closed position slide 202; Micro switch assembly 300, fully open switch 310, open contact 311, fully closed switch 320, closed contact 321; Feedback shaft 400, cam assembly 410, first retaining ring 411, second retaining ring 412, fixing pin 413, mounting hole 401; Terminal assembly 500; Valve body 600, actuator 610. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] This invention relates to a linear limit switch that can be adapted to different strokes. It is designed specifically for two mainstream linear pneumatic control valves: diaphragm valves and angle seat valves. It can be widely used in fluid control scenarios with high requirements for pipeline valve sealing and switch position feedback accuracy, such as food and beverage, biopharmaceutical, fine chemical, and municipal water treatment.

[0022] like Figures 1 to 6As shown, this invention provides a linear limit switch adaptable to different strokes, including a housing 100, a support frame 200, a micro switch assembly 300, and a feedback shaft 400. The feedback shaft 400 is located at the center of the housing 100. One end of the feedback shaft 400 is connected to the actuator 610 of the valve body 600, and the other end extends through the bottom of the housing 100 to the top of the housing 100, moving up and down synchronously with the opening and closing actions of the valve body 600. The support frame 200 is disposed inside the housing 100 and has an open position slide groove 201 and a closed position slide groove 202 extending along the up-and-down movement direction of the feedback shaft 400. The micro switch assembly 300 includes a fully open switch 310 and a fully closed switch 320, which are respectively installed in the open position slide groove 201 and the closed position slide groove 202, and can be fixed to the support frame 200 after position adjustment. The fully open switch 310 has an open contact 311 facing the feedback shaft 400, and the fully closed switch 320 has a closed contact 321 facing the feedback shaft 400. By adjusting the installation positions of the fully open switch 310 and the fully closed switch 320 along the open slide groove 201 and the closed slide groove 202, the effective detection distance between the open contact 311 and the closed contact 321 can be changed to match the actual stroke of the corresponding valve body 600. A cam assembly 410 is provided on the feedback shaft 400, and the cam assembly 410 includes at least one retaining ring.

[0023] In one embodiment, the cam assembly 410 includes a first fixing ring 411, which is fixedly mounted on the feedback shaft 400 and moves up and down synchronously with the feedback shaft 400. When the valve body 600 moves from the fully closed position to the fully open position, the feedback shaft 400 drives the first fixing ring 411 to move upward, and the first fixing ring 411 moves to a position that contacts the open contact 311 of the fully open position switch 310, so as to drive the fully open position switch 310 to act and output a fully open signal of the valve body 600; when the valve body 600 moves from the fully open position to the fully closed position, the feedback shaft 400 drives the first fixing ring 411 to move downward, and the first fixing ring 411 moves to a position that contacts the close contact 321 of the fully closed position switch 320, so as to drive the fully closed position switch 320 to act and output a fully closed signal of the valve body 600.

[0024] With only the first retaining ring 411 installed, the first retaining ring 411 sequentially engages with the open contact 311 and the closed contact 321 during the up-and-down movement of the feedback shaft. This structure is suitable for situations where the actual stroke of the valve body actuator can cover the detection distance between the open contact 311 and the closed contact 321, and is particularly suitable for linear angle seat valves and linear diaphragm valves with a stroke of 20-35 mm.

[0025] In another embodiment, such as Figures 4-6As shown, the cam assembly 410 includes a first retaining ring 411 and a second retaining ring 412 spaced apart along the axial direction of the feedback shaft 400. The first retaining ring 411 is used to cooperate with the open contact 311 of the fully open switch 310, and the second retaining ring 412 is used to cooperate with the closed contact 321 of the fully closed switch 320. When the feedback shaft 400 moves to the fully open position with the actuator 610 of the valve body 600, the first retaining ring 411 triggers the fully open switch 310; when the feedback shaft 400 moves to the fully closed position with the actuator 610 of the valve body 600, the second retaining ring 412 triggers the fully closed switch 320.

[0026] The axial spacing between the first fixed ring 411 and the second fixed ring 412 forms a stroke compensation distance. Based on the actual travel distance of the actuator 610 of the valve body 600 from the fully closed position to the fully open position, the actual detection distance between the open contact 311 and the closed contact 321 is equal to the sum of the actual travel distance and the stroke compensation distance. Therefore, when the actual travel distance of the valve body 600 is less than the detection distance between the open contact 311 and the closed contact 321, the stroke compensation distance between the first fixed ring 411 and the second fixed ring 412 can be set to allow the two fixed rings to trigger the fully open switch 310 and the fully closed switch 320 at their respective positions. This double fixed ring structure is particularly suitable for linear angle seat valves and linear diaphragm valves with a travel distance of 5–20 mm.

[0027] By setting two types of cam assemblies 410—single fixed ring and double fixed ring—the appropriate triggering structure can be selected according to the actual stroke of the actuator 610 of the valve body 600. For valve bodies 600 with a large stroke, a single fixed ring can complete the detection of fully open and fully closed positions, resulting in a simpler structure. For valve bodies 600 with a small stroke, a double fixed ring structure with stroke compensation distance can be used, eliminating the need to excessively reduce the preset detection distance between the open contact 311 and the closed contact 321, thus achieving full open and full closed position detection. This facilitates the adaptation of the same limit switch to linear angle seat valves and linear diaphragm valves with different strokes, while preserving installation, adjustment, and positioning space for the micro switch assembly 300.

[0028] Furthermore, such as Figure 4 and Figure 5As shown, the feedback shaft 400 is provided with a plurality of mounting holes 401 spaced apart along its axial direction. Each mounting hole 401 is used to provide optional installation positions for the first fixing ring 411 and the second fixing ring 412. The first fixing ring 411 and the second fixing ring 412 are both provided with fixing holes corresponding to the mounting holes 401. During assembly, according to the actual stroke of the actuator 610 of the valve body 600 and the preset detection distance between the open contact 311 and the closed contact 321, the corresponding mounting hole 401 on the feedback shaft 400 is selected, and the fixing pin 413 is made to pass through the fixing hole of the first fixing ring 411 or the second fixing ring 412 and the selected mounting hole 401 in sequence, thereby fixing the first fixing ring 411 or the second fixing ring 412 onto the feedback shaft 400.

[0029] When the cam assembly 410 includes only the first fixed ring 411, the corresponding mounting hole 401 can be selected according to the actual movement stroke of the valve body 600 to adjust the axial installation position of the first fixed ring 411 on the feedback shaft 400, so that the first fixed ring 411 can trigger the open contact 311 when the feedback shaft 400 moves upward to the fully open position, and trigger the closed contact 321 when the feedback shaft 400 moves downward to the fully closed position.

[0030] When the cam assembly 410 includes a first fixed ring 411 and a second fixed ring 412, the mounting holes 401 for installing the first fixed ring 411 and the second fixed ring 412 can be selected respectively to adjust the axial spacing between the two fixed rings, thereby adjusting the stroke compensation distance. After the first fixed ring 411 and the second fixed ring 412 are fixed, they correspond to the trigger positions of the fully open switch 310 and the fully closed switch 320 respectively, so that the double fixed ring cam assembly 410 can be adapted to linear stroke valve bodies 600 with different actual strokes.

[0031] By providing several mounting holes 401 on the feedback shaft 400 and using fixing pins 413 to position the first fixing ring 411 and the second fixing ring 412 within the selected mounting holes 401, the position of a single fixing ring or the interval between two fixing rings can be adjusted without replacing the feedback shaft 400 and the fixing rings. The cooperation between the fixing pins 413 and the mounting holes 401 provides a clear axial positioning reference for the fixing rings, which helps reduce the possibility of axial movement of the fixing rings during the valve's reciprocating motion, leading to trigger position offset, and improves the ease of adjustment and repeatability stability of the opening and closing position signals under different valve stroke conditions.

[0032] Furthermore, such as Figure 8As shown, the support frame 200 is provided with a first switch base 210 and a second switch base 220, which are arranged perpendicularly to each other and both extend along the axial direction of the feedback shaft 400. The first switch base 210 is provided with two parallel open position slide grooves 201, and the second switch base 220 is provided with two parallel close position slide grooves 202. Both the two open position slide grooves 201 and the two close position slide grooves 202 extend along the axial direction of the feedback shaft 400.

[0033] like Figure 9 As shown, the fully open switch 310 is installed between two open-position slides 201 and can be synchronously adjusted along the axial direction of the feedback shaft 400 under the guidance of the two open-position slides 201; the fully closed switch 320 is installed between two closed-position slides 202 and can be synchronously adjusted along the axial direction of the feedback shaft 400 under the guidance of the two closed-position slides 202. Both the open-position slides 201 and the closed-position slides 202 are provided with scales for indicating the axial position of the switches, with a minimum scale division of 0.1 mm.

[0034] After adjusting the fully open switch 310 and the fully closed switch 320 to positions that match the actual stroke of the valve body 600, the fully open switch 310 and the fully closed switch 320 are fixed to the corresponding first switch base 210 and second switch base 220 by fixing pins or fixing screws and nuts to maintain their adjusted axial positions.

[0035] Two parallel open-position slideways 201 or closed-position slideways 202 form a dual-point guide and support for the same microswitch. Combined with a scale for quantitative adjustment of the switch position, this allows for a clear adjustment reference for the installation positions of the fully open switch 310 and the fully closed switch 320. After positioning, the fixing pin or screw locks the corresponding switch, which helps reduce the possibility of deflection, tilting, or axial movement of the microswitch assembly 300 under long-term reciprocating motion or vibration conditions of the valve body 600. This reduces the deviation in the open and closed position detection, improves the adaptability of the limit switch to different valve strokes, enhances adjustment convenience, and increases the stability of the position detection.

[0036] Furthermore, such as Figure 9As shown, the open contact 311 is located at the upper end of the inner side of the fully open switch 310, and the closed contact 321 is located at the lower end of the inner side of the fully closed switch 320. The open contact 311 and the closed contact 321 are perpendicular to each other, and their actuating ends are both oriented towards the feedback shaft 400. By setting the fully open contact 311 and the fully closed contact 321 at the upper and lower ends of the inner side of the corresponding microswitches, the two contacts can be staggered in the axial direction of the feedback shaft 400, corresponding to the movement paths of the cam assembly 410 on the feedback shaft 400 in the fully open and fully closed positions, respectively. The triggering directions of the two contacts are perpendicular to each other, allowing the triggering actions of the fully open switch 310 and the fully closed switch 320 to occur in different directions, reducing the possibility of mutual interference between the two contacts during installation, adjustment, and operation. Meanwhile, the actuating ends of both contacts are set towards the feedback shaft 400, so that the cam assembly 410 on the feedback shaft 400 can directly contact the corresponding contacts along the predetermined motion path. This helps to shorten the transmission path between the cam assembly 410 and the contacts, reduce the possibility of trigger position deviation caused by offset contact or lateral collision, and thus improve the detection stability of the valve body 600's fully open and fully closed position signals.

[0037] Furthermore, the axial length of the open position slide 201 is 20 mm, and the axial length of the closed position slide 202 is 5 mm. The fully open position switch 310 can be axially adjusted within the range of 0 to 20 mm along the open position slide 201, and the fully closed position switch 320 can be axially adjusted within the range of 0 to 5 mm along the closed position slide 202.

[0038] In the baseline installation state, the center positions of the fully open switch 310 and the fully closed switch 320 have an initial distance of 10 mm along the axial direction of the feedback shaft 400. When the fully open switch 310 and the fully closed switch 320 are adjusted in directions that move them away from each other, the effective detection distance between the open contact 311 and the closed contact 321 increases with the adjustment amount of the fully open switch 310 and the fully closed switch 320. Therefore, the effective detection distance can be adjusted within the range of 5 to 35 mm to match different linear stroke valve bodies 600 whose actual stroke falls within this range. By setting open position slide grooves 201 and closed position slide grooves 202 with different adjustment strokes, the fully open switch 310 and the fully closed switch 320 can be adjusted along the axial direction of the feedback shaft 400, thereby changing the actual detection distance between the open contact 311 and the closed contact 321.

[0039] When the cam assembly 410 includes only the first fixed ring 411, the first fixed ring 411 triggers the open contact 311 and the closed contact 321 respectively during the up-and-down movement of the feedback shaft 400. At this time, the actual detection distance between the open contact 311 and the closed contact 321 corresponds to the actual stroke of the actuator 610 of the valve body 600. The positions of the fully open switch 310 and the fully closed switch 320 can be adjusted along the open slide groove 201 and the closed slide groove 202 to match the actual detection distance between the two contacts with the actual stroke of the valve body 600.

[0040] When the cam assembly 410 includes a first fixed ring 411 and a second fixed ring 412, the axial distance between the first fixed ring 411 and the second fixed ring 412 forms a stroke compensation distance. At this time, the actual detection distance between the open contact 311 and the closed contact 321 is equal to the sum of the actual movement stroke of the actuator 610 of the valve body 600 and the stroke compensation distance. Based on the actual movement stroke of the valve body 600, the stroke compensation distance is first determined by adjusting the installation position of the first fixed ring 411 and the second fixed ring 412 on the feedback shaft 400. Then, the axial positions of the fully open switch 310 and the fully closed switch 320 are adjusted respectively through the open slide groove 201 and the closed slide groove 202 so that the actual detection distance between the two contacts corresponds to the "actual movement stroke plus the stroke compensation distance".

[0041] The open-position slide 201 provides a large position adjustment range for the fully open switch 310, used for overall adaptation to different valve body 600 strokes and different fixed ring intervals; the closed-position slide 202 provides a smaller range of fine adjustment for the fully closed switch 320, used for calibration of the fully closed trigger position. Through the linkage of the open-position slide 201, the closed-position slide 202, and the stroke compensation distance, the open and closed position detection requirements of both large-stroke and small-stroke valve bodies 600 can be met without making the open-position contact 311 and the closed-position contact 321 too close. When the distance between the open-position contact 311 and the closed-position contact 321 is too small, the installation, adjustment, and locking space of the two microswitches is limited, and the influence of installation errors, axial movement of the feedback shaft 400, and vibration during the movement of the valve body 600 on the trigger position increases relatively, easily leading to deviations in the open and closed position detection or unstable signals. Therefore, by adapting the stroke compensation distance between the first fixed ring 411 and the second fixed ring 412 to the small stroke valve body 600, accurate position detection can be achieved while maintaining a reasonable detection distance between the open position contact 311 and the closed position contact 321.

[0042] Meanwhile, the two open-position slides 201 and the two closed-position slides 202 respectively form a dual-point guide and support for the corresponding micro switch assembly 300, which can maintain its installation posture stability during the adjustment of the switch position; combined with the locking effect of the slide scale and the fixing pin or fixing screw, it is beneficial to improve the accuracy of the stroke compensation distance and detection distance setting, the stability of repeat positioning, and the adaptability under different valve stroke conditions.

[0043] Furthermore, such as Figure 3 As shown, the limit switch also includes a terminal assembly 500, which includes a terminal holder fixedly disposed within the housing 100. The terminal assembly 500 is electrically connected to the fully open switch 310 and the fully closed switch 320 respectively, and is used to connect to an external control system to transmit the fully open and fully closed signals of the valve body 600 output by the fully open switch 310 and the fully closed switch 320 to the external control system, thereby realizing remote monitoring of the movement state of the valve body 600.

[0044] Furthermore, such as Figure 1 and Figure 2 As shown, the housing 100 includes a bottom shell 110 and a top shell 120. The bottom shell 110 and the top shell 120 are respectively provided with corresponding screw holes on their peripheries. The bottom shell 110 and the top shell 120 are fixedly connected by fasteners passing through the screw holes to jointly form a cylindrical cavity that accommodates the support frame 200, the micro switch assembly 300 and the feedback shaft 400.

[0045] like Figure 7 As shown, the inner bottom surface of the bottom shell 110 is provided with a first mounting seat 112 and a second mounting seat 113. The first mounting seat 112 includes two first cylindrical mounting posts spaced apart along the inner bottom surface of the bottom shell 110, and each first cylindrical mounting post is provided with a first mounting hole that passes through it along its axial direction; the support frame 200 is fixed to the first mounting seat 112 by fasteners that pass through the first mounting holes.

[0046] The second mounting base 113 includes two second cylindrical mounting posts spaced apart along the inner bottom surface of the base shell 110. Each second cylindrical mounting post has a second mounting hole extending through it axially. The upper end face of each second cylindrical mounting post gradually slopes downward from the side away from the central axis of the base shell 110 towards the side closer to the central axis of the base shell 110, such that the height of the upper end face of each second cylindrical mounting post on the side closer to the central axis of the base shell 110 is lower than the height of the upper end face on the side away from the central axis of the base shell 110. The terminal holder in the terminal assembly 500 is fixed to the second mounting base 113 by fasteners passing through the second mounting holes.

[0047] By tilting the upper end face of the second cylindrical mounting post toward the central axis of the bottom shell, clearance space and installation space can be provided for the side of the terminal block facing the central axis of the bottom shell, reducing the possibility of spatial interference between the terminal block and other components inside the shell, and facilitating the installation of the terminal assembly within the limited internal space of the shell.

[0048] like Figure 2 and Figure 3 As shown, the feedback shaft 400 is arranged along the central axis of the cylindrical cavity. The lower end of the feedback shaft 400 passes through the mounting hole in the center of the bottom shell 110 and is connected to the actuator 610 of the valve body 600 through a thread at the lower end. The upper end of the feedback shaft 400 extends toward the front shell 120. The bottom shell 110 and the front shell 120 are respectively provided with bearing mounting parts for mounting the lower bearing 111 and the upper bearing 121. The feedback shaft 400 is rotatably engaged with the bottom shell 110 and the front shell 120 through the lower bearing 111 and the upper bearing 121, respectively, to provide radial support and axial positioning for the feedback shaft 400. The upper bearing 121 and the lower bearing 111 are embedded in the housing 100, so that the feedback shaft 400, the bearings and the housing 100 form a compact integrated assembly structure.

[0049] The housing 120 has a shaft hole at its center corresponding to the feedback shaft 400. The shaft hole is used to accommodate the upper bearing 121 and provide extension space for the upper end of the feedback shaft 400. A transparent cover plate 130 is provided above the shaft hole, covering the shaft hole so that the movement of the feedback shaft 400 and the retaining ring can be observed without disassembling the housing 100.

[0050] The bottom shell 110 and the top shell 120 together form a cylindrical cavity, and the upper bearing 121 and the lower bearing 111 are used to support and position the feedback shaft 400. This can improve the installation stability of the feedback shaft 400 during the up and down movement process and reduce the possibility that the feedback shaft 400 will be misaligned and affect the mating position of the fixed ring with the open contact 311 and the closed contact 321.

[0051] The upper bearing 121 and lower bearing 111 are embedded within the housing 100, which helps to reduce the overall size of the limit switch and allows the support structure of the feedback shaft 400 to form a compact assembly with the housing 100. The transparent cover 130 allows observation of the movement of the feedback shaft 400 and the fixing ring without disassembling the housing 100, facilitating installation, debugging, and abnormal condition inspection. The terminal assembly 500 centrally connects the micro switch assembly 300 to the external control system via a terminal block, which facilitates the unified output and remote observation of the fully open and fully closed signals of the valve body 600.

[0052] Furthermore, such as Figure 2As shown, the limit switch also includes a range extender copper sleeve 140, which is sleeved on the upper end of the feedback shaft 400 and located between the feedback shaft 400 and the housing 120. The range extender copper sleeve 140 extends axially along the feedback shaft 400, with its lower end sleeved on the upper end of the feedback shaft 400 and its upper end inserted into the shaft hole of the housing 120.

[0053] When the feedback shaft 400 moves downward to the fully closed position along with the actuator 610 of the valve body 600, the upper end of the feedback shaft 400 remains within the extension copper sleeve 140, and the upper end of the extension copper sleeve 140 remains within the shaft hole of the housing 120, thereby reducing the possibility that the upper end of the feedback shaft 400 may disengage from the shaft hole due to the large stroke. Subsequently, when the feedback shaft 400 moves upward, the extension copper sleeve 140 can provide guidance for the feedback shaft 400, keeping the feedback shaft 400 aligned with the shaft hole, thereby reducing the possibility that the feedback shaft 400 may become misaligned, stuck, or unable to reset smoothly.

[0054] By setting the extended range copper sleeve 140, the guiding continuity and positional stability of the feedback shaft 400 during the large stroke reciprocating motion can be improved, reducing the risk of failure of the housing 100 due to the feedback shaft 400 disengaging from the shaft hole of the housing 120. This is especially beneficial for meeting the requirements of explosion-proof application scenarios with high requirements for the reliability of the housing 100.

[0055] The present invention will now be described through specific embodiments.

[0056] Example 1

[0057] This embodiment provides a linear limit switch adaptable to different strokes, including a housing 100, a support frame 200, a micro switch assembly 300, and a feedback shaft 400. The micro switch assembly 300 includes a fully open switch 310 and a fully closed switch 320. The fully open switch 310 and the fully closed switch 320 can be axially adjusted along the open slide groove 201 and the closed slide groove 202, respectively, and are fixed by fixing pins or fixing screws after adjustment.

[0058] In this embodiment, the cam assembly 410 includes a first fixing ring 411 and a second fixing ring 412 axially spaced along the feedback shaft 400. The first fixing ring 411 engages with the open contact 311 of the fully open switch 310, and the second fixing ring 412 engages with the closed contact 321 of the fully closed switch 320. The actual detection distance between the open contact 311 and the closed contact 321 is set to 8 mm, and the axial spacing between the first fixing ring 411 and the second fixing ring 412 forms a stroke compensation distance, which is set to 3 mm.

[0059] When the actuator 610 of the valve body 600 moves from the fully closed position to the fully open position, the feedback shaft 400 drives the first fixed ring 411 and the second fixed ring 412 to move synchronously; the first fixed ring 411 moves to the position that contacts the open contact 311, driving the fully open switch 310 to act and output a fully open signal; when the actuator 610 of the valve body 600 moves from the fully open position to the fully closed position, the second fixed ring 412 moves to the position that contacts the closed contact 321, driving the fully closed switch 320 to act and output a fully closed signal.

[0060] In this embodiment, the actual stroke of the actuator 610 in the valve body 600 is 5 mm, and the actual detection distance between the open contact 311 and the closed contact 321 is 8 mm, satisfying the condition that the actual detection distance equals the sum of the actual stroke and the stroke compensation distance. Therefore, by setting a stroke compensation distance of 3 mm, the limit switch can be adapted to linear angle seat valves and diaphragm valves with a stroke of 5 mm.

[0061] Example 2

[0062] This embodiment has the same basic structure as Embodiment 1, except that: the cam assembly 410 includes a first fixed ring 411 and a second fixed ring 412 spaced apart along the axial direction of the feedback shaft 400, the actual detection distance between the open contact 311 and the closed contact 321 is set to 25 mm, and the stroke compensation distance between the first fixed ring 411 and the second fixed ring 412 is set to 5 mm.

[0063] In this embodiment, the actual stroke of the actuator 610 in the valve body 600 is 20 mm. By fixing the first fixing ring 411 and the second fixing ring 412 to the corresponding mounting hole positions on the feedback shaft 400, the axial interval between the two fixing rings is 5 mm; then, by adjusting the positions of the fully open switch 310 and the fully closed switch 320 through the open position slide groove 201 and the closed position slide groove 202, the actual detection distance between the open contact 311 and the closed contact 321 is 25 mm.

[0064] When the actuator 610 of the valve body 600 moves to the fully open position, the first retaining ring 411 contacts the open contact 311, driving the fully open switch 310 to actuate and output a fully open signal; when the actuator 610 of the valve body 600 moves to the fully closed position, the second retaining ring 412 contacts the closed contact 321, driving the fully closed switch 320 to actuate and output a fully closed signal. Since the actual detection distance of 25 mm between the open contact 311 and the closed contact 321 is equal to the sum of the actual movement stroke of the valve body 600 (20 mm) and the stroke compensation distance (5 mm), this embodiment can be adapted to linear angle seat valves and diaphragm valves with a movement stroke of 20 mm.

[0065] Example 3

[0066] This embodiment has the same basic structure as Embodiment 1, except that the cam assembly 410 only includes a first fixing ring 411, which is fixedly mounted on the feedback shaft 400. The actual detection distance between the open contact 311 and the closed contact 321 is set to 35 mm.

[0067] In this embodiment, the actual stroke of the actuator 610 of the valve body 600 is 35mm. By adjusting the positions of the fully open switch 310 and the fully closed switch 320 along the open position slide 201 and the closed position slide 202, the actual detection distance between the open contact 311 and the closed contact 321 corresponds to the actual stroke of the actuator 610 of the valve body 600.

[0068] When the actuator 610 of the valve body 600 moves from the fully closed position to the fully open position, the feedback shaft 400 drives the first fixing ring 411 to move upward to contact the open contact 311, thus driving the fully open switch 310 to actuate. When the actuator 610 of the valve body 600 moves from the fully open position to the fully closed position, the feedback shaft 400 drives the first fixing ring 411 to move downward to contact the closed contact 321, thus driving the fully closed switch 320 to actuate. Because the actual travel of the valve body 600 in this embodiment is relatively large, the first fixing ring 411 can trigger both the open and closed contacts 311 during the up-and-down movement of the feedback shaft 400, thus eliminating the need for a second fixing ring 412 for travel compensation. This embodiment is suitable for linear angle seat valves and diaphragm valves with a travel of 35 mm.

[0069] The above embodiments show that, for a linear valve body 600 with a large stroke, a cam assembly 410 including only a first fixed ring 411 can be used, and the detection distance between the two contacts can be adjusted by the open position slide groove 201 and the closed position slide groove 202 to match the actual stroke of the valve body 600; for a linear valve body 600 with a small stroke, a cam assembly 410 including a first fixed ring 411 and a second fixed ring 412 can be used, and the stroke compensation distance between the two fixed rings can be combined with the adjustment of the open position slide groove 201 and the closed position slide groove 202 to achieve full open and full closed position detection while maintaining a reasonable detection distance between the open position contact 311 and the closed position contact 321.

[0070] like Figure 11 As shown, the present invention also provides a control device, including a valve body 600, an external control system, and a linear limit switch adaptable to different strokes in any of the above embodiments.

[0071] like Figure 10As shown, the limit switch is installed on the upper end of the valve body 600. The feedback shaft 400 of the limit switch is connected to the actuator 610 of the valve body 600 so as to move up and down synchronously with the actuator 610. The terminal assembly 500 of the limit switch is electrically connected to the fully open switch 310 and the fully closed switch 320 respectively, and is connected to the external control system.

[0072] When the actuator 610 of the valve body 600 moves to the fully open position, the feedback shaft 400 drives the cam assembly 410 to trigger the fully open position switch 310, and the terminal assembly 500 transmits the corresponding fully open signal to the external control system. When the actuator 610 of the valve body 600 moves to the fully closed position, the feedback shaft 400 drives the cam assembly 410 to trigger the fully closed position switch 320, and the terminal assembly 500 transmits the corresponding fully closed signal to the external control system. The external control system monitors the current open / closed state of the valve body 600 based on the received fully open or fully closed signal.

[0073] The control device can select either a cam assembly 410 that includes only the first fixed ring 411 or a cam assembly 410 that includes the first fixed ring 411 and the second fixed ring 412, based on the actual stroke of the actuator 610 of the valve body 600. By adjusting the positions of the fully open switch 310, the fully closed switch 320 and the fixed rings, the actual detection distance of the limit switch can be matched with the movement stroke of the valve body 600.

[0074] By connecting a linear limit switch adaptable to different strokes to an external control system, the mechanical motion states of the valve body 600 in the fully open and fully closed positions can be converted into remotely transmittable electrical signals, enabling the external control system to promptly acquire the position status of the valve body 600. Combining single-fixed-ring and double-fixed-ring cam assemblies 410, and the adjustment functions of the open-position slide groove 201 and the closed-position slide groove 202, the control device can adapt to linear valve bodies 600 with different actual strokes, which helps reduce the possibility of inaccurate position detection due to differences in the valve body 600's stroke.

[0075] In this embodiment, the external control system is equipped with a valve position anomaly detection logic module. When only a fully open signal or only a fully closed signal is received, a valve position jamming alarm is automatically triggered. The valve position anomaly detection logic module of the external control system is implemented using an industrial-grade PLC logic unit, requiring no additional hardware costs and allowing for functional deployment solely through ladder logic programming.

[0076] Specifically, the fully open signal from the limit switch is connected to port DI1 of the PLC, and the fully closed signal is connected to port DI2 of the PLC. Both ports are set with a 200ms hardware anti-bounce delay to completely eliminate false triggering problems caused by valve body movement jitter and contact bounce in industrial environments. Under normal operating conditions, after the valve body completes the fully open action, port DI1 continuously receives a high-level signal while port DI2 remains low; after the valve body completes the fully closed action, port DI2 continuously receives a high-level signal while port DI1 remains low. Both states are considered normal valve positions. When ports DI1 and DI2 simultaneously detect high-level signals, or when both ports remain low for more than 3 seconds, the logic module automatically determines that there is a valve position jamming fault, immediately triggers the system's audible and visual alarm, and simultaneously outputs a forced pressure relief command to the valve body actuator to prevent the actuator from continuously increasing pressure in the jammed state, which could damage the diaphragm. If only the DI1 port receives a high-level signal for more than 5 seconds, or only the DI2 port receives a high-level signal for more than 5 seconds, the logic module determines it as a single-channel contact sticking fault and outputs a separate "limit switch contact abnormal" alarm signal to prompt maintenance personnel to replace the contact components in advance to avoid unplanned downtime.

[0077] The external control system also includes a reserved low-power wireless communication interface. This interface can connect to an external LoRa wireless transmission module to synchronously upload valve position status signals to a remote maintenance platform. The reserved low-power wireless communication interface uses a TTL level serial port definition and can be directly plugged into the Siwei Wireless LoRa6500Pro series or Ebitec E22 series LoRa data transmission modules without the need for additional adapter circuit boards. Specifically, the VCC pin of the wireless communication interface outputs a stable 3.3V power supply, and the TXD and RXD pins are directly cross-connected to the serial port pins of the LoRa module. The reserved SET configuration pin can be directly connected to the module's configuration control terminal. Users can remotely modify the LoRa module's communication frequency band, NET ID, and NODE ID parameters via external configuration software without disassembling the device casing.

[0078] The actual communication process of the low-power wireless communication interface is as follows: Connect two external LoRa modules to the wireless communication interfaces of two control devices at different workstations. Configure the NET IDs of both modules to the same value using PC configuration software, and set the NODE IDs to 001 and 002 respectively. Configure the air communication rate to 2.4kbps. Remove the configuration jumper cap on the USB adapter board to allow the modules to enter normal transparent transmission mode. The valve position signals from both control devices can then be synchronously uploaded to a remote maintenance platform 1.2km away via the LoRa network. In industrial sites with factory walls obstructing the view, the packet loss rate can be controlled to within 0.1%. The built-in AES128 encryption function of the module can be enabled with a single click via the reserved control pin on the interface, preventing unauthorized tampering of the valve position signals during wireless transmission.

[0079] The contents not described in detail in this specification are existing technologies known to those skilled in the art.

[0080] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They do not limit the scope of protection of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

[0081] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A linear limit switch adaptable to different strokes, characterized in that, include: The micro switch assembly includes: a fully open switch and a fully closed switch; The support frame is provided with an axially extending open position slide groove and a closed position slide groove. The fully open position switch is adjustablely installed in the open position slide groove, and the fully closed position switch is adjustablely installed in the closed position slide groove. Housing for mounting the support frame and the micro switch assembly; A feedback shaft is disposed within the housing and fixedly connected to the actuator of the valve body. A cam assembly is provided on the feedback shaft, and the cam assembly includes at least one first fixed ring. When the feedback shaft moves with the actuator to the fully open position of the valve body, the cam assembly triggers the fully open position switch; when the feedback shaft moves with the actuator to the fully closed position of the valve body, the cam assembly triggers the fully closed position switch.

2. The linear limit switch adaptable to different strokes according to claim 1, characterized in that, The support frame includes a first switch base and a second switch base, which are arranged perpendicularly to each other. The open position slide groove is provided on the first switch base, and the closed position slide groove is provided on the second switch base.

3. The linear limit switch adaptable to different strokes according to claim 2, characterized in that, The open position slide groove includes two parallel open position slide grooves disposed on the first switch base, and the closed position slide groove includes two parallel closed position slide grooves disposed on the second switch base. The fully open switch is installed between the two open position slides, and the fully closed switch is installed between the two closed position slides.

4. The linear limit switch adaptable to different strokes according to claim 3, characterized in that, After the axial position adjustment is completed, the fully open switch and the fully closed switch are respectively fixed to the first switch base and the second switch base by fixing pins or fixing screws and nuts.

5. The linear limit switch adaptable to different strokes according to claim 1, characterized in that, The fully open switch has an open contact at the upper end of its inner side, and the fully closed switch has a closed contact at the lower end of its inner side. The triggering directions of the open contact and the close contact are perpendicular to each other, and the actuating ends of the open contact and the close contact are both oriented toward the feedback shaft.

6. The linear limit switch adaptable to different strokes according to claim 5, characterized in that, The cam assembly includes only the first retaining ring; The first retaining ring moves axially with the feedback shaft and contacts the open contact when the feedback shaft moves to the fully open position of the valve body, and contacts the closed contact when the feedback shaft moves to the fully closed position of the valve body.

7. The linear limit switch adaptable to different strokes according to claim 5, characterized in that, The cam assembly further includes a second retaining ring, and the first retaining ring and the second retaining ring are spaced apart along the axial direction of the feedback shaft; The first retaining ring is used to trigger the fully open position switch when the feedback shaft moves to the fully open position of the valve body, and the second retaining ring is used to trigger the fully closed position switch when the feedback shaft moves to the fully closed position of the valve body; The axial spacing between the first fixed ring and the second fixed ring constitutes the stroke compensation distance, and the actual detection distance between the open contact and the closed contact is equal to the sum of the actual movement stroke of the valve body actuator and the stroke compensation distance.

8. The linear limit switch adaptable to different strokes according to claim 7, characterized in that, The feedback shaft is provided with a plurality of mounting holes spaced apart along its axial direction, and both the first fixing ring and the second fixing ring are provided with fixing holes corresponding to the mounting holes. The first retaining ring and the second retaining ring are fixed to the feedback shaft by means of retaining pins passing through corresponding retaining holes and selected assembly holes, respectively, so as to adjust the stroke compensation distance.

9. The linear limit switch adaptable to different strokes according to claim 1, characterized in that, The limit switch further includes a terminal assembly, which includes two terminal blocks fixedly disposed inside the housing. The terminal assembly is electrically connected to the fully open switch and the fully closed switch respectively, and is used to connect to an external control system to output a fully open signal and a fully closed signal for the valve body.

10. A control device, characterized in that, Includes a valve body, an external control system, and a linear limit switch adaptable to different strokes as described in any one of claims 1 to 9; The feedback shaft of the limit switch is connected to the actuator of the valve body, and the terminal assembly of the limit switch is connected to the external control system. The external control system is used to receive the fully open signal output by the fully open switch and the fully closed signal output by the fully closed switch, so as to monitor the open and closed status of the valve body. The external control system is equipped with a valve position abnormality judgment logic module. When only a fully open signal or only a fully closed signal is received, the valve position jamming alarm is automatically triggered. The external control system has a reserved low-power wireless communication interface, which can be connected to a LoRa wireless transmission module to synchronously upload the valve position status signal to the remote operation and maintenance platform.

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