Samson’s locator, complete with an actuator and a handwheel; the DCS commands 100 at the site while closing it to 50, and commands 50 at the site with full closure
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The medium is liquid nitrogen at a temperature of over -100 degrees. The handwheel switches can be set to 0 and 100, after which the handwheel is turned back to its original position. The issue of the valve getting stuck can be ruled out; I suspect that perhaps the handwheel was not in the correct position before, which caused the limitation
This of yours is the rhythm by which the actuator needs to be adjusted to the zero and full positions
A few days ago, before driving, they said it had expired
Then I can only suspect that the handwheel isn’t in the correct position or that there’s some kind of limit in place. It doesn’t seem to be that case though. This is a pneumatically operated valve; before using the dual-action positioner, should the handwheel not be set in the fully closed position?
When I arrived for the night shift today, I asked whether it was possible to buy a Thomson locator that allows calibration without having to remove it from the control valve, so that calibration can be done offline; it was said that this is possible, as Thomson’s devices have such a function
I’m not sure if it can work offline; it seems that the zero and full positions are incorrect. It’s best to perform calibration online
Set the handwheel to the automatic position, and first perform an automatic verification.
This handwheel has no markings; manual/automatic position
It would be good to have a photo showing the handwheel, the actuator, and the feedback mechanism, etc
The control valve is installed horizontally, directly inside the cryogenic chamber; the conditions there are extremely harsh. I’ll take some photos tomorrow for you to see – the pipes are covered in thick layers of frost everywhere
We have encountered this issue before; it was a problem with the selection of the actuator. There are two types of such actuators – one type can only be adjusted to 50% opening, while another type allows for full opening