What is the purpose of the vent valve on a magnetic flap level gauge?
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As the title suggests, the vent valve of a magnetic flap level gauge doesn’t seem to be very useful; I see it is included in some model selections, but I’ve never seen one in use. Also, what kind of magnetic flap is suitable for acetic acid or propionic acid? Would a 304 body with a 316 float work? Due to the high temperatures involved, it’s difficult to choose a version with a PTFE lining. Furthermore, what kind of level gauge is appropriate for use in distillation towers? Our company used electric float level gauges before, and they worked well with good stability, but many smaller companies find them too expensive, so they opt for cheaper alternatives. Double-flange type level gauges also cost around eight to ten thousand yuan; magnetic flap level gauges might be a viable option as well.
Zero calibration? I guess it should be like that
The housing of the flap is a small container in which non-condensable gases – those that cannot be cooled by the ambient temperature, such as nitrogen or methane – gradually accumulate at the top inside the gauge chamber; more and more of these gases may accumulate over time； There are also those where the equipment is sealed and pressurized with N2 before driving. Therefore, a vent at the top is standard equipment for level gauges; as for whether a valve is installed or not, it depends on the factory’s practices. For acetic acid and propionic acid, which type of magnetic flap should be chosen? The main body should be the same as that of the pipeline; if corrosion is a concern due to the thin walls of the float, titanium material can be considered. 18-8 stainless steel and titanium are standard materials for floats; titanium floats are standard components in acetic acid/*AO acid plants. Titanium bodies are also available, and they aren’t as expensive as one might think. . For industrial plant levels, the traditional methods such as differential pressure and float switches are still used; the electrical output from these devices serves as a \"secondary signal\", which can be in the form of an analog signal or a switch signal. The test setup can indeed use a flip plate along with a transmitter. . .
We use magnetic flap level gauges quite frequently. Some of these level gauges suffer from blockages at their upper and lower inlets and outlets, or the float may get stuck, which is when a vent valve becomes necessary.
The upper end of the magnetic flap level gauge we selected has a hole, through which a valve can be installed, or it can be sealed directly with screws. It can be drained or cleaned if necessary.
Venting – it may serve the purpose of discharging waste as well as releasing exhaust gases
Looking at the replies under this post, for such a simple question, not a single person got it right! A magnetic flap, or a glass plate, or a float, usually has a valve on it called an exhaust valve, which is used to vent the gas phase. There is a valve below, called the drain valve. Both valves are standard fittings, but sometimes the upper vent valve is replaced with a plug that can be unscrewed and then re-tightened. When there is a problem with the level gauge, such as too much dirt under the magnetic flip plate that affects the measurement and requires maintenance, it is necessary to first close the primary valve, then open the drain valve to release the fluid. Sometimes it isn’t possible to remove all the fluid completely due to trapped air, so it is needed to open the valve above in order to clear everything thoroughly. But sometimes there is still dirt, so some oil or water needs to be poured in from above, and sometimes steam is used for purging. When measuring media that are **extremely flammable or explosive and other highly dangerous media, sealed discharge is required, and neither of these two valves can be omitted!
The medium we are measuring is a liquid, but gas-liquid mixing can occur easily; however, the float does not give an accurate indication
In other words, in the gas-liquid two-phase state the float is at a higher position, so a vent valve is needed to discharge the gas phase?
But sometimes there is still dirt, so some oil or water needs to be poured in from above, and sometimes steam is used for purging. When measuring media that are **extremely flammable or explosive and other highly dangerous media, sealed discharge is required, and neither of these two valves can be omitted! I understand these two points. The mention of holding one’s breath earlier refers to the situation where the float drops too quickly during waste discharge, thereby blocking the waste discharge valve. Neither of these valves can be missing; they are necessary to ensure that no material leaks out. Because our company has never used magnetic flap valves with vent valves. There are no threads on the upper part either; it’s completely sealed. In the past, when the company designed and selected instruments, those with drain valves were chosen as well.