Help needed regarding issues with pneumatic control butterfly valves
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We have a pneumatically actuated control butterfly valve here, with a handwheel. The current situation is that as the valve position increases from low to high, it reaches around 42 and can no longer go any further. If the handwheel is turned to a position greater than 42, and then a signal is sent to set the valve to a lower position, it is still possible to pass the 42 mark. The cylinder and positioning mechanism were removed, and then the movement was attempted again – it worked smoothly. 42 is a value that can be passed. Turning the valve with the handwheel is also very loose. The 42 setting is also quite loose; there’s no feeling of tightness. The locator has been replaced now, but the problem still exists. Has anyone ever encountered this situation? The positioner is from Siemens, the cylinder is from Sumo, and the valve is also from Sumo.
This post was last edited by CHANGBAISHI on 2020-5-19 at 15:53. Please upload images to facilitate discussion. When in automatic mode, the position controlled by the handwheel should be set to 100% fully open so that automatic control can operate without restrictions. It can also be seen from the appearance that it is set at an unrestricted position (maximum or minimum). For reference
The itinerary wasn’t chosen incorrectly; after confirming the previous parameters, initialize it
This post was last edited by liuyuqian on 2020-5-19 23:29. To initialize the locator: 1. Hold down the \"small hand button\" for 5 seconds; once inside, use the \"small hand button\" to find step 50, then press \"+\" for 5 seconds until \"ocay\" appears. Release the button, and then use the \"small hand button\" to exit； 2. Use the “+” and “-” buttons to close the valve completely, adjust the control knob to an opening degree of 5–9, and then use the “+” and “-” buttons again to open the valve fully, adjusting the control knob to an opening degree of 95 ； 3. Use the “+” and “-” buttons to set the valve to position 50 (check whether the actual valve position is indeed at 50). 4. Hold down the “small hand button” for 5 seconds to reach step 4, then press “+” for 5 seconds; the valve will enter self-tuning mode. 5. Once completed, hold down the “small hand button” for 5 seconds to exit and switch to automatic mode; remote adjustment should then work properly. Pay attention to the reaction of step 7.
I’m not quite sure what you mean. How does the movement take place after the locator and cylinder are removed? If the problem persists even after replacing the positioner, then consider the cylinder – maybe the spring isn’t installed properly, which causes stress at around 42. For example, the spring is twisted
Confirm the type of cylinder; it is likely a fork-type one. Offline tuning works fine, which indicates that there should be no problems with the valve body, actuator, and positioner. The torque output of the fork puller is not linear; verify whether the torque at 42° meets the required torque value. Or the fork mechanism itself is worn, resulting in uneven output. For reference.