Switching position feedback device of straight stroke pneumatic actuating mechanism
By using a rotatable coaxial connection device and a replyer in the straight-stroke pneumatic actuator, the problem of relative position deviation between the valve feedback lever and the stroke switch turn arm is solved, and the stable transmission of the switch position signal is achieved and the long life of the feedback device is reduced, thereby reducing maintenance costs.
Patent Information
- Application Number
- CN202421969230.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-14
- Publication Date
- 2025-02-28
- Estimated Expiration
- 2034-08-14
AI Technical Summary
The valve feedback lever of the straight-stroke pneumatic actuator is offset from the stroke switch crank arm relative to the position, resulting in the inability to accurately transmit the switch position signal, and it is easy to cause damage to the stroke switch when it is opened or closed quickly.
The feedback rod is physically connected to the replyer by a rotatable coaxial connection device, buffering the impact force, avoiding hard impact, and a replyer is used to replace the original mechanical position stroke switch.
It effectively avoids hard collision between the feedback lever and the stroke switch turn arm, improves the transmission stability and reliability of the switch position signal, extends the service life of the feedback device, and reduces maintenance costs.
Smart Images
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Abstract
Description
Technical Field
[0001] The utility model relates to a switch position feedback device for a linear pneumatic actuator. Background Art
[0002] Linear pneumatic actuators use compressed air to act on a cylinder spring to open and close valves. The fully open and fully closed positions are typically indicated by the movement of a mechanical travel switch attached to the cylinder. When the pneumatic actuator actuates, it moves a feedback lever connected to the valve stem. When the actuator reaches the fully open or fully closed position, the feedback lever contacts the travel switch arm, actuating the switch and transmitting a signal to the DCS for display and control. However, frequent valve opening and closing, valve vibration, and feedback lever rotation can cause the valve feedback lever and travel switch arm to shift relative to each other, preventing the feedback lever from accurately contacting the arm and delaying timely transmission of the valve position signal to the DCS for control. Furthermore, rapid valve opening and closing can easily impact the travel switch arm, causing damage and failure. For critical actuators such as the turbine's high- and low-pressure bypass valves, the pump recirculation control valve, and the turbine body drain valve, accurate indication of their open and close positions is directly related to turbine efficiency and impacts the unit's safe and stable operation. Utility Model Content
[0003] The utility model is to solve the above-mentioned technical problems and provides a switch position feedback device for a linear pneumatic actuator.
[0004] In order to achieve the above purpose, the utility model adopts the following technical solutions:
[0005] A linear pneumatic actuator switch position feedback device comprises: an actuator and a valve stem, wherein a fixed base is fixed on the actuator, the fixed base is fixed to a feedback device, the output end of the feedback device is fixed to a coaxial connection device, the coaxial connection device is fixed to a feedback rod through a through hole of the fixed base, and a fixed rod is fixed to the valve stem of the actuator, and the fixed rod passes through a sliding hole of the feedback rod.
[0006] The linear pneumatic actuator switch position feedback device has a fixed base that is a square frame structure with fixing holes provided thereon for fixing. Beneficial effects
[0007] 1. The utility model physically connects the feedback rod and the feedback device of the responder through a rotatable coaxial connection device to avoid the switch position feedback failure caused by falling off and separation.
[0008] 2. The coaxial connection device of the utility model can buffer the impact force generated when the valve moves quickly, avoid hard collision between the feedback rod and the travel switch arm, and effectively extend the service life of the feedback device.
[0009] 3. This utility model uses one reply device to replace the original two mechanical position limit switches, which can further reduce the cost of equipment maintenance. BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Attachment Figure 1 It is a structural diagram of the utility model;
[0011] Attachment Figure 2 It is a structural diagram of the reply device and the fixed base;
[0012] In the figure: 1. Feedback lever; 2. Fixed base; 3. Coaxial connection device; 4. Responder; 5. Valve stem; 6. Fixed lever; 7. Actuator; 8. Fixed hole; 9. Sliding hole. DETAILED DESCRIPTION
[0013] Reference Figure 1 A linear pneumatic actuator switch position feedback device, which consists of: an actuator 7 and a valve stem 5, a fixed base 2 is fixed on the actuator, the fixed base is fixed to the responder 4, the output end of the responder is fixed to the coaxial connection device 3, the coaxial connection device is fixed to the feedback rod 1 through the through hole of the fixed base, a fixed rod 6 is fixed on the valve stem of the actuator, and the fixed rod passes through the sliding hole 9 of the feedback rod.
[0014] The fixed base of the linear pneumatic actuator switch position feedback device is a square frame structure with fixing holes 8 for fixing.
[0015] Linear pneumatic actuators rely on compressed air acting on a cylinder spring to actuate the valve's opening and closing motion. The fully open and fully closed positions are typically indicated by the action of a mechanical travel switch mounted on the cylinder. When the pneumatic actuator actuates, it moves the feedback lever on the valve stem, causing it to press against the travel switch arm in the fully open or fully closed position, actuating the travel switch. This signal is then transmitted to the DCS for display and control. For critical actuators such as the turbine's high- and low-pressure bypass valves, the steam pump recirculation regulating valve, and the turbine body drain valve, accurate indication of their opening and closing position is directly related to turbine operating efficiency and impacts the unit's safe and stable operation. This device replaces the existing two mechanical travel switches with a simple feedback mechanism as the valve's opening and closing position feedback device. Through a rotatable coaxial connection, the valve's linear motion is converted into circular motion by the feedback mechanism, eliminating impact from the valve's feedback lever on the feedback mechanism and preventing feedback mechanism failure. This improves the stability and reliability of the switch position signal transmission.
[0016] The fixed base is mounted on the actuator, the reply device is fixed to the fixed base by bolts, the output end of the reply device is fixed to the rotatable coaxial connection device, one end of the feedback rod is mounted at the input of the rotatable coaxial connection device and fixed by a nut, a fixed rod 6 is fixed to the valve stem of the actuator, and the fixed rod passes through the sliding hole 9 of the feedback rod;
[0017] During installation, adjust the fixed base and install it in the middle of the actuator's full stroke, ensuring that the feedback lever is horizontal when the actuator is in the middle position. When the valve is fully open, the feedback lever drives the rotatable coaxial connection device to move the feedback device to the fully open position. At this time, the contact position in the feedback device is adjusted to transmit the fully open signal to the DCS. When the valve is fully closed, the operation steps are the same as for fully opening.
Claims
1. A switch position feedback device for a linear pneumatic actuator, comprising: The actuator and valve stem are characterized in that: a fixed base is fixed on the actuator, the fixed base is fixed to the reply device, the output end of the reply device is fixed to the coaxial connecting device, the coaxial connecting device is fixed to the feedback rod through the through hole of the fixed base, and a fixed rod is fixed on the valve stem of the actuator, and the fixed rod passes through the sliding hole of the feedback rod.
2. The switch position feedback device for a linear pneumatic actuator according to claim 1 is characterized in that: The fixed base is a square frame structure, and is provided with fixing holes for fixing.