Vacuum pump measurement method

The function of vacuum pump is to remove gas molecules from the vacuum chamber, reduce the gas pressure in the vacuum chamber, and make it reach the required vacuum degree. Generally speaking, there is a large range from atmosphere to extremely high vacuum. So far, no vacuum system can cover this range. Therefore, in order to meet the requirements of process index, working efficiency and equipment working life of different products, different vacuum system configuration needs to be selected for different vacuum sections.

Thermocouple vacuum gauge: a vacuum gauge that measures the vacuum degree based on the principle that the potential of the thermocouple is related to the temperature of the heating element and the temperature of the element is related to the heat conduction of the gas.

Ionization vacuum gauge: it is composed of cylinder collector, grid and filament in the center of grid. The cylinder collector is outside the grid. The hot cathode emits electrons to ionize the gas molecules, and the ions are collected by the collector. The vacuum gauge measures the gas pressure according to the collected ion current.

Composite vacuum gauge: it is composed of thermocouple vacuum gauge and hot cathode ionization vacuum gauge. The measurement range is from atmosphere to 10-5pa.

Cold cathode ionization meter: there are a pair of cathode plates at both ends of the anode cylinder. Under the action of external magnetic field, panning discharge is formed in the anode cylinder to generate ions. The vacuum meter measures the gas pressure according to the size of the ion flow collected by the cathode plate.

Resistance vacuum gauge: a vacuum gauge that measures the vacuum degree through the bridge circuit based on the principle that the resistance of the heating element is related to the temperature and the temperature of the element is related to the gas conduction.

Mclaw vacuum gauge: also known as compression type vacuum gauge, it compresses the gas to be measured to a very small volume with mercury (or oil), and then compares the liquid column difference between the open tube and the closed tube, and directly calculates the gas pressure with Boyle’s law.

Capacitance film vacuum gauge: This is a kind of hot cathode ionization gauge with cathode and collector inverted. The collector is a filament, which is placed in the center of the grid, and the filament is placed outside the grid, thus reducing the influence of soft X-ray, extending the lower limit of measurement, and measuring ultra-high vacuum. Three different gauges are integrated into a small and economical gauge. The process pressure and basic pressure are measured from 5×10-10 to 1500 mbar. Due to the advantages of high accuracy, fast dynamic response, no relation between the measurement results and gas composition, corrosion resistance and pressure shock resistance, the capacitance film vacuum meter has been paid more and more attention. It can replace mercury manometer, oil pressure gauge, resistance vacuum gauge, thermocouple vacuum gauge and even partially ionization gauge.

Common vacuum pumps include dry screw vacuum pump, liquid ring pump, reciprocating pump, slide valve pump, rotary vane pump, roots pump and diffusion pump. These pumps are essential main pumps in the application of vacuum technology in various industries of national economy. Vacuum pump is a kind of device or equipment that uses mechanical, physical, chemical or physicochemical methods to extract air from the container to obtain vacuum. Generally speaking, vacuum pump is a device which can improve, produce and maintain vacuum in a closed space by various methods.

Vacuum pump measurement method