Vacuum instrument commonly used in vacuum furnace

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There are two main types of vacuum instruments commonly used in vacuum furnace:
One is the vacuum measuring instrument, also known as the vacuum gauge;
Second, the vacuum system gas flow meter, also known as the gas flowmeter.

1. Vacuum measuring instrument
(1) Static deformation vacuometer (also known as elastic element vacuometer) USES the effect of atmosphere on the surface of a vessel connected with vacuum to generate elastic deformation to measure pressure.

(2) The static liquid level vacuum gauge USES the liquid level difference at both ends of the U-shaped tube to measure the pressure.

(3) The principle of the compression type vacuum gauge is to apply Boyle’s law on the basis of the U-shaped tube. It is to increase the pressure of a certain amount of gas to be measured after isothermal compression, so that the U-shaped tube vacuum gauge can be used for measurement. Then, the relationship between volume and pressure is used to calculate the pressure to be measured.

(4) The heat conduction vacuum gauge is made based on the principle of gas heat conduction and pressure under low pressure. Resistance vacuum gauge and thermocouple vacuum gauge are commonly used.

(5) The thermal radiation vacuum gauge is made based on the principle of gas thermal radiation and pressure under low pressure.

(6) Ionization gauge is made by using the principle that gas molecules are ionized by collisions of hot particles under low pressure and the ion flow generated changes with pressure, such as hot-cathode ionization vacuum juice, cold-cathode ionization vacuum gauge and radioactive ionization vacuum gauge.

(7) The discharge tube indicator USES the gas discharge condition and discharge color related to pressure to determine the vacuum degree, which can generally only be used as a qualitative measurement.

(8) Other vacuum meters include diaphragm type vacuum meter, magnetic suspension rotor vacuum meter, field microscope, quadrupole mass spectrometer, cyclotron mass spectrometer, radio frequency mass spectrometer, etc.

2. Vacuum system gas flow meter
(1) Gas flowmeter When the vacuum furnace is used for carburizing, nitriding and other chemical heat treatment processes, it is necessary to input gas or liquid cementing agent into the vacuum chamber, usually using the rotor flowmeter to detect and control the flow rate.

(2) Vacuum needle valve Vacuum fine tuning valve is used to regulate the flow of gas or liquid media into the vacuum chamber, the body usually must be made of stainless steel.