The process temperature is 135°C; can magnetostriction be used?
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Dear teachers, the process temperature is 135°C; it is a mixture of 66% sulfuric acid and ***. The level gauge is installed at the top to measure the sulfuric acid interface. The tank is filled with liquid at a pressure of 3 bar. Currently, a fluorine-lined reed switch level gauge is being used, and it is planned to replace it with a fluorine-lined magnetostrictive level gauge. Is it correct to use a magnetostrictive level gauge? Today, the seller from Croni called and said that PFA-lined magnetostrictive sensors cannot be used in this type of process. Under these process conditions, apart from the double-flange level gauge (one is already installed on the tank), what other type of level gauge can be used to measure the sulfuric acid interface?
Under such temperature conditions, magnetostriction may indeed not be as effective. A dual-flange differential pressure transmitter will work perfectly; the diaphragm can be made of tantalum or lined with PTFE, which ensures accuracy and low cost. Adding temperature compensation for level adjustment is sufficient.
What needs to be measured is the interface; dual-flange level gauges require stable density, otherwise there will be measurement errors. Reed switches can meet this requirement, and there is no need to modify magnetic expansion types
Currently, a reed switch level gauge is being used; it has a fluorine-coated interior, and it’s not clear whether the coating is made of PTFE or PTA. Why can a reed switch be used in this application? In the same system, fluorine-lined butterfly valves are used, which are also lined with fluorine. Teacher, do you think they can’t be used because the fluorine lining cannot withstand a temperature of 135 degrees?
This post was last edited by qugd on 2021-2-26 at 13:57. It’s not a matter of whether the material is resistant to corrosion, but rather the effect of expansion and contraction caused by temperature changes on its strength and service life. The lining of the instrument is certainly not as thick or as strong as that of other devices
Are you sure it’s full? If the total liquid level is fixed, use a blow-out type level gauge. Tantalum is chosen for the material.
? I mean using a pneumatic differential pressure gauge; when the total liquid level remains constant, changes in the interface can reflect changes in differential pressure. It works very well in practice
Which blowing device should be chosen? With the tank always filled with liquid at a pressure of 3 kilograms, the material will flow back into the air pipe