Issues with the air path of the control valve
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May I ask how the air path for this control valve works? Please, experts, help solve this!
My neck is so tired. My head is twisted at 90°, which hinders my thinking. Rotate the image
The typical air circuit layout for control valves is air filter and pressure regulator – positioner – air-operated valve – limit switch – actuator. However, it’s not clear what type of control valve this is, nor whether it controls movement in one direction or the other
Weren’t any photos taken when the valve was removed at first? ?
Check to see if there are any known valves to compare with! There should be many such valve catalysts
In the diagram, the black line represents the path of the inlet flow, which ultimately reaches the valve positioner. If we ignore all the other complex pipelines, then there is a single pipe that leads from the positioner to either above or below the diaphragm head; this constitutes a standard control valve (FO or FC). The yellow line in the diagram goes from the hold-down valve to the upper side of the diaphragm head, and it appears that there is also a pipeline connected to the lower side of the diaphragm head at the location indicated by the red arrow. Therefore, it can be inferred that it is a double-acting valve. The pipeline near the pressure maintaining valve is too messy, making it difficult to see the outlet pipelines; thus, it’s hard to conduct an analysis
This post was last edited by ZhiGE on 2019-4-11 at 20:07. Typical applications of the FISHER377 hold valve: 1. When the instrument air pressure is normal, the actuator adjusts the valve position; 2. When the instrument pressure is low, the valve locks or holds in place. 3. There are typically 3 types of gas path connections; by referring to the gas path diagram in the attachment, it is possible to determine which function will be achieved.