Selection of liquid level gauge for vacuum tank
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Description of the situation: 1. Vacuum level in the reflux tank: -70±5. 2. Medium: natural benzene. 3. Temperature: 30±5°C. 4. The parameters vary little. 5. The reflux tank is small; the height is 1.2 meters as measured by a glass plate level gauge. A glass plate level gauge is used on-site to monitor the liquid level, while the DCS system in the control room uses a float level gauge for remote monitoring. The outdoor liquid level reading differs significantly from that shown on the DCS, and the float level gauge may experience sticking. Can a double-flange differential pressure transmitter be used? What problems might arise if it is used? What type of level gauge should be chosen if it’s not possible? Thank you so much for your reply, expert! I’m a complete novice in the chemical industry; please offer your guidance
Double-flange differential pressure transmitters should be usable； It depends on the model you choose; some older models with silicone oil capillaries are not suitable ； It is recommended to consider installing a radar level gauge. Thank you
Why are the older models with silicone oil not suitable? Is there any instruction?
It is susceptible to external temperatures, resulting in significant deviations and fluctuations； This is especially evident under negative pressure! Thank you
The use of differential pressure in a vacuum is very inaccurate. It is recommended to use patches
Dual flanges are not recommended, as bulging can occur on the negative pressure side! ! ! Differential pressure measurement is not recommended!
Radar or capacitive types are better; differential pressure types are not very accurate when used in negative pressure conditions, as they tend to exhibit errors
How cheap are remote-controlled magnetic flap valves? The effect should be good; magnetostriction works too