Valve limit switch

Abstract

The invention relates to the technical field of switches, in particular to a valve limit switch which comprises a disc, the disc is coaxially connected outside the output end of a rotating shaft and arranged between two reeds at intervals, and the disc is provided with a conductive path generated based on the rotating angle of a valve clack. The conductive path at least comprises a closing conductive position corresponding to the closing limit position of the valve clack and an opening conductive position corresponding to the opening limit position of the valve clack, and when the disc rotates along with the valve clack, the closing conductive position and the opening conductive position can make contact with the contact and sequentially send out a limit closing signal and a limit opening signal. The discs are arranged between the two reeds at intervals, the reeds cannot be bent no matter what state the discs are in, the service life of the reeds is prolonged, and traditional dynamic components such as swing arms and shifting pieces are omitted; and meanwhile, a resistance difference exists between the closed conductive position and the opening conductive position, so that one group of contacts can correspond to various control signals.

Description

Technical Field

[0001] The present invention relates to the technical field of switches, specifically a valve limit switch. Background Art

[0002] In the field of industrial automation control, the precise control of valves is crucial. As a key device that can accurately feedback the open or closed position state of a valve, a valve limit switch is widely used in the pipeline systems of many industries such as petroleum, chemical, electric power, and metallurgy.

[0003] Existing valve limit switches generally adopt a mechanical contact structure, that is, a cam linkage structure, and there are the following core problems:

[0004] Mechanical fatigue and life limitation: The traditional toggle trigger structure relies on the repeated bending of an elastic toggle to trigger a microswitch, resulting in metal fatigue fracture, and the life is only 100,000 - 500,000 times. In high - requirement scenarios such as nuclear power, frequent replacement of the switch causes economic losses due to shutdown.

[0005] Insufficient triggering accuracy: There is an angular error of more than ±2° between the cam and the contact, which cannot meet the requirements of precise control. Summary of the Invention

[0006] The present invention aims at the problems in the prior art and provides a valve limit switch. The specific technical solutions are as follows:

[0007] A valve limit switch, comprising:

[0008] A housing, installed on the valve;

[0009] A microswitch, installed in the housing. The input end of the microswitch has two oppositely arranged reeds, and the end faces of the two reeds facing each other have corresponding contacts;

[0010] A rotating shaft, the input end of the rotating shaft is drivingly connected to the valve stem, and the output end rotatably extends into the housing;

[0011] And a disc, coaxially connected to the output end of the rotating shaft and spaced between the two reeds. The disc has a conductive path generated based on the rotation angle of the valve flap. The conductive path at least includes a closed conductive position corresponding to the closed limit position of the valve flap and an open conductive position corresponding to the open limit position of the valve flap. When the disc rotates with the valve flap, the closed conductive position and the open conductive position can contact the contacts and sequentially emit a limit - closed signal and a limit - open signal.

[0012] As a further technical solution of the present invention, the contact is a point - type structure, and the conductive path is an annular structure coaxial with the disc.

[0013] As a further technical solution of the present invention, the contact is a radially extending sheet structure, and the conductive path is an involute structure.

[0014] As a further technical solution of the present invention, the closed conductive position and the open conductive position have a resistance difference.

[0015] As a further technical solution of the present invention, the two reed pieces are driven by a pre-pressure to make the contact closely adhere to the surface of the disc to form axial anti-vibration.

[0016] As a further technical solution of the present invention, there is at least one transition conductive position between the closed conductive position and the open conductive position in the conductive path.

[0017] As a further technical solution of the present invention, in the conductive path, the resistance values of multiple transition conductive positions on the path from the closed conductive position to the open conductive position increase or decrease.

[0018] As a further technical solution of the present invention, adjacent closed conductive positions, open conductive positions, and transition conductive positions are isolated by an insulating region.

[0019] The beneficial effects of the present invention are as follows:

[0020] (1) In the present application, the disc is arranged between the two reed pieces at intervals. No matter what state the disc is in, it will not cause the bending of the reed pieces, extending the service life of the reed pieces. The traditional dynamic components such as swing arms and paddles are eliminated. There is only planar sliding friction between the contact and the disc, and the service life is increased to more than 10 million times.

[0021] (2) In the present application, at the same time, the closed conductive position and the open conductive position have a resistance difference, so that a set of contacts can correspond to multiple control signals, replacing the traditional multi-cam control method, updating the layout inside the housing, reducing the required internal space of the housing, and reducing the volume of the housing.

[0022] (3) In the present application, through the setting of the transition conductive position, not only the extreme open position and the extreme closed position of the valve during rotation can be detected, but also the opening and closing process of the valve can be monitored, and the real-time opening of the valve can be accurately fed back. By the triggering sequence and timing of the conductive regions, it can be judged whether the valve is stuck in a specific interval. The operation and maintenance personnel can view the working status of the valve in different conductive regions in real time through the terminal. Description of the Drawings

[0023] Figure 1 Shows the structural schematic diagram of Embodiment 1;

[0024] Figure 2 Shows the structural schematic diagram of the disc in Embodiment 1;

[0025] Figure 3 A schematic diagram of the structure of Example 2 is shown;

[0026] Figure 4 The schematic diagram of the structure of the disc in Example 2 is shown.

[0027] Description of the drawings: 100, housing; 110, upper housing; 120, lower housing; 200, micro switch; 210, reed; 220, contact; 300, rotating shaft; 400, disc; 410, closed conductive position; 420, open conductive position; 430, transition conductive position; 440, insulating area. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments.

[0029] Figure 1 A schematic diagram of the structure of Embodiment 1 is shown; Figure 2 The structure diagram of the disc 400 in Embodiment 1 is shown; Figure 3 A schematic diagram of the structure of Example 2 is shown; Figure 4 A schematic structural diagram of the disc 400 in Embodiment 2 is shown.

[0030] The valve limit switch comprises a housing 100, a micro switch 200, a rotating shaft 300 and a disc 400, wherein the housing 100 is integrally mounted on the valve, the micro switch 200 is mounted in the housing 100 and electrically connected to the outside, and is used to convert the mechanical movement of the valve into an electrical signal and send it to the solenoid valve control unit, so as to timely prevent the valve from being excessively opened and closed; one end of the rotating shaft 300 is rotatably arranged in the housing 100, and the other end extends and is transmission-connected to the valve stem, and can rotate synchronously with the valve stem to transmit the rotation of the valve stem to the housing 100; the disc 400 is coaxially connected to the insertion end of the rotating shaft 300, and can rotate synchronously with the rotation of the rotating shaft 300, that is, the disc 400 will rotate with the rotation of the valve disc, so as to monitor the rotation angle of the valve disc in real time, and is used to toggle the input end of the micro switch 200 to send different control signals.

[0031] Figure 1 and Figure 3 In the embodiment, the housing 100 includes an upper housing 110 and a lower housing 120, which cover each other to form an internal sealed accommodation space for accommodating the micro switch 200, and the upper housing 110 and the lower housing 120 are installed by bolts.

[0032] Figure 1 and Figure 3In it, the input end of the microswitch 200 has two relatively arranged reed pieces 210. Corresponding contacts 220 are provided on the end faces of the two reed pieces 210 facing each other. The two reed pieces 210 are driven by a pre-pressure to approach each other and make the two contacts 220 fit together to form a circuit; in actual use, when the two contacts 220 come into contact, a circuit is formed, that is, an electrical signal is sent to the solenoid valve control unit, and the two reed pieces 210 are driven to approach and contact each other by the pre-pressure before use, indicating that the microswitch 200 is a normally-on structure; it is beneficial to the subsequent contact effect with the disk 400 spaced between the two reed pieces 210, forming axial anti-vibration and ensuring that the signal is uninterrupted and not lost.

[0033] Figure 2 and Figure 4 In it, the disk 400 is spaced between the two reed pieces 210, and the two contacts 220 are respectively pressed against the two end faces of the disk 400. The disk 400 has a conductive path generated based on the rotation angle of the valve flap. The conductive path at least includes a closed conductive position 410 corresponding to the closed limit position of the valve flap and an opening conductive position 420 corresponding to the opening limit position of the valve flap. When the disk 400 rotates with the valve flap, the two contacts 220 can contact the closed conductive position 410 and the opening conductive position 420 and sequentially send out a limit closing signal and a limit opening signal; that is to say, as the disk 400 rotates, when the closed conductive position 410 in the conductive path on the disk 400 corresponds to the positions of the two contacts 220, at this time, the two contacts 220 are conducted through the closed conductive position 410 to form a loop to send out an electrical signal, that is, the limit closing signal; when the opening conductive position 420 in the conductive path on the disk 400 corresponds to the positions of the two contacts 220, at this time, the two contacts 220 are conducted through the opening conductive position 420 to form a loop to send out an electrical signal, that is, the limit opening signal; by arranging the disk 400 between the two reed pieces 210, no matter what state the disk 400 is in, it will not cause the bending of the reed pieces 210, extending the service life of the reed pieces 210. The traditional swing arms, paddles and other dynamic components are cancelled. There is only planar sliding friction between the contacts and the disk, and the service life is increased to more than 10 million times of the shell; there is a resistance difference between the closed conductive position 410 and the opening conductive position 420; in actual use, due to the different resistance values of the closed conductive position 410 and the opening conductive position 420, the electrical signals generated in the loop are also different, so as to distinguish the limit opening signal and the limit closing signal; this design enables a set of contacts to correspond to multiple control signals, replacing the traditional multi-cam control method. Only one disk 400 and two microswitches 200 are required to realize the control of multiple signals, updating the layout inside the shell 100, which can reduce the internal space required for the shell 100, reduce the volume of the shell 100, and make the shell 100 more suitable for some narrow spaces.

[0034] Continue to refer toFigure 2 and Figure 4 in the conduction path, there is at least one transitional conduction position 430 between the closed conduction position 410 and the open conduction position 420; through the setting of the transitional conduction position 430, not only can the extreme open position and the extreme closed position of the valve during rotation be detected, but also the opening and closing process of the valve can be monitored. For example, when the transitional conduction position 430 is set at the middle position between the closed conduction position 410 and the open conduction position 420, when the two groups of reed switches 210 contact the transitional conduction position 430 to form a conduction loop, it indicates that the valve opening reaches 50%; it can accurately feedback the real-time opening of the valve, and judge whether the valve is stuck in a specific interval through the triggering sequence and timing of the conductive area. The operation and maintenance personnel can view the working status of the valve in different conductive areas in real time through the terminal; in Figure 2 and Figure 4 , three groups of transitional conduction positions 430 are set, that is, signals are sent when the valve opening reaches 25%, 50% and 75%, and the valve opening situation can be monitored in real time; in the conduction path, the resistance values of multiple transitional conduction positions 430 on the path from the closed conduction position 410 to the open conduction position 420 increase or decrease; the difference in signals is distinguished through the change in resistance value to realize the possibility of real-time monitoring; when the resistance value of the closed conduction position 410 is greater than the resistance value of the open conduction position 420, the multiple transitional conduction positions 430 decrease on the path extending from the closed conduction position 410 to the open conduction position 420, and vice versa.

[0035] For example, the resistance value of the closed conduction position 410 is 50Ω, the resistance value of the open conduction position 420 is 10Ω, and three groups of transitional conduction positions 430 are set, then the resistance values of the three transitional conduction positions 430 can be 40Ω, 30Ω and 20Ω respectively.

[0036] It should be noted that in some other embodiments, the number and position of the transitional conduction positions 430 are not specifically limited and can be arranged according to the monitoring accuracy.

[0037] Continue to refer to Figure 2 and Figure 4 , the adjacent closed conduction position 410, open conduction position 420 and transitional conduction position 430 are isolated by an insulating area 440; the insulating area ensures that when the valve is in a non-target position, the contacts cannot form a closed loop by blocking the current path between the contacts, thus avoiding the output of false signals. For example, when the valve is in the insulating area, even if there is vibration or mechanical offset, the contacts still remain disconnected, preventing the control system from misjudging as the "fully open" or "fully closed" state; significantly reducing the arc risk between the contacts, preferably made of ceramic material.

[0038] Embodiment 1

[0039] See Figure 1 and Figure 2 , the contact 220 is a dot structure, and the conductive path is an annular structure coaxial with the disk 400; that is to say, the radial position of the contact 220 is the same as the radial position of the conductive path. When the disk 400 rotates, the contact 220 moves along the trajectory of the conductive path to ensure the accuracy of monitoring.

[0040] Embodiment 2

[0041] See Figure 3 and Figure 4 , the contact 220 is a radially extending sheet structure, and the conductive path is an involute structure; that is to say, although the contact 220 is a radially extending sheet structure, it can still form a single path, which can prevent multiple conductive regions from contacting the contact 220 at the same time, and the involute design can be adapted to valves with valve flaps opening and closing more than 360°, effectively saving space.

[0042] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them.

Claims

1. Valve limit switch, characterized in that, Comprising: A housing (100), mounted on the valve; A microswitch (200), mounted within the housing (100), the input end of the microswitch (200) having two oppositely arranged reed pieces (210), and corresponding contacts (220) being provided on the end faces of the two reed pieces (210) facing each other; A rotating shaft (300), the input end of the rotating shaft (300) being drivingly connected to the valve stem, and the output end rotatably extending into the housing (100); And a disc (400), the disc (400) being coaxially connected to the outside of the output end of the rotating shaft (300) and being spaced between the two reed pieces (210), the disc (400) having a conductive path generated based on the rotation angle of the valve flap, the conductive path at least including a closed conductive position (410) corresponding to the closed limit position of the valve flap and an opening conductive position (420) corresponding to the opening limit position of the valve flap, and when the disc (400) rotates with the valve flap, the closed conductive position (410) and the opening conductive position (420) can contact the contacts (220) and sequentially emit a limit closing signal and a limit opening signal.

2. The valve limit switch according to claim 1, characterized in that: The contact (220) is of a point-like structure, and the conductive path is of an annular structure coaxial with the disc (400).

3. The valve limit switch according to claim 2, wherein: The contact (220) is of a radially extending flaky structure, and the conductive path is of an involute structure.

4. The valve limit switch according to claim 2 or 3, characterized in that: The closed conductive position (410) and the opening conductive position (420) have a resistance difference.

5. The valve limit switch according to claim 2 or 3, characterized in that: The two reed pieces (210) are driven by a pre-pressure to make the contacts (220) closely adhere to the surface of the disc (400) to form axial anti-vibration.

6. The valve limit switch according to claim 5, characterized in that: In the conductive path, there is at least one transition conductive position (430) between the closed conductive position (410) and the opening conductive position (420).

7. The valve limit switch according to claim 6, characterized in that: In the conductive path, the resistance values of multiple transition conductive positions (430) on the path from the closed conductive position (410) to the opening conductive position (420) increase or decrease.

8. The valve limit switch according to claim 6, wherein: Adjacent closed conductive positions (410), opening conductive positions (420) and transition conductive positions (430) are isolated by an insulating region (440).

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