Must a self-acting control valve be used for the nitrogen sealing of storage tanks?
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The nitrogen seal pressure is 1 kPa gauge. 1. Is it possible to use a control valve + pressure transmitter? 2. Compared with self-acting control valves, which one has a better effect?
All I’ve seen are self-acting types; control valves are just too expensive.
The requirements for nitrogen sealing are not high; a self-acting control valve is sufficient. If pressure display is required, a pressure transmitter + control valve can also be used.
Our storage tanks are equipped with control valves and pressure transmitters, and there are two sets of such equipment: one control valve for intake and one for exhaust, along with one pressure transmitter. Step-by-step control; you can check it out.
Considering the requirements for the nitrogen-sealed medium, it’s likely difficult to achieve accurate control at 1 kPa with control valves, and the cost is also too high
A self-regulating valve will do.
Any one will do; it’s just that the control valve is a bit expensive – it depends on your operating conditions. If high requirements are needed, then a control valve must be used; if the requirements are not high, self-acting valves are cheaper. However, self-acting valves do tend to break easily; we have had to replace several of our self-acting control valves. Either we refrain from using control valves, or we replace them with manual valves or breather valves instead.
If it’s to be effective, a combination of a control valve and a pressure transmitter is the best choice~~~Self-acting valves are advantageous in terms of cost, but they are not suitable for applications that require high reliability~~~It’s advisable for the poster to consider all relevant factors before making a decision~~
Here, we have replaced all the self-regulating valves with self-adjusting valves coupled with pressure transmitters. A pressure transmitter for the nitrogen seal in the storage tank is essential; the cost difference lies only in the valves themselves
All of them can be achieved, and there are various ways to do so. It can be controlled via two control valves in a split-range manner, or by a combination of two self-acting control valves, or by a combination of a control valve and a breather valve.