The compressed Maxwell vacuum gauge is a good standard instrument for vacuum measurement in the pressure range of - 3 Pa of 1x10. Of course, the above-mentioned Maxwell vacuum gauge refers to the compression type vacuum gauge with the inner diameter of the measuring capillary tube between 0.6 and 1.2mm, and the volume of the compressed ball is between 150-1500ml. It belongs to the PM-8 type compressed Maxwell vacuum gauge produced by our company at present, and the measurement range is between - 3PA and 5pa of 5x10.
Pm-7 lifting type Maxwell vacuum gauge is an upgraded version of rotary Maxwell vacuum gauge. The measuring range of pm-7 lifting type Maxwell vacuum gauge is about 0.1pA ~ 1000Pa, and the measurement error is controlled within 10%. Its advantages are mainly shown in the following aspects:
1、 The label is made according to one-to-one data. First, the inner diameter of the capillary tube and the volume of the compressed ball are measured, and then the mathematical coefficient K is calculated. According to the calculation theory, the various vacuum degrees below the (0) position line can be obtained by using the square calibration method, which makes it impossible for individuals who like to copy this kind of vacuum meter.
2、 Now when measuring, it is not necessary to rotate the whole vacuum gauge at right angles. As long as the instrument is vertically fixed on the facade, the air suction port is connected with the vacuum system. In vacuum measurement, just lift the mercury storage device below to let mercury slowly enter the compression bulb and measuring capillary. When the height of mercury column reaches the set line, directly look at the measuring capillary The scale line corresponding to the inner mercury column is the vacuum degree at the moment. After reading it, slowly put down the mercury storage device to complete the measurement.
3、 Now, because of the simplified structure of the glass tube, the probability of the glass tube being damaged by vibration has been reduced to the lowest point; and a pressurizer device is added in the design of the glass instrument, so that the vacuum gauge can quickly balance the pressure inside the vacuum gauge when measuring.
4、 The reference line of the current measurement meets the requirements of the original design of the compressed Maxwell vacuum gauge. Unlike the rotary vacuum gauge, the height of the mercury column will be more and more upward with the amplification of the vacuum degree, resulting in great error.
5、 The volume of pm-7 lifting Maxwell vacuum gauge is now one fourth of that of the former rotary Maxwell vacuum gauge (300x70x32mm). The structure is compact, the measurement accuracy is good, and the service life is 5 to 10 times of the old one.
6、 In the design of glass pipe, the principle of convenient cleaning is strived for, so that the unprofessional technical workers can also dismantle it by themselves, clean the pollutants inside the glass pipe, and replace it with pure mercury and vacuum hose, which saves a lot of unnecessary economic expenditure.
In conclusion, pm-7 lifting Maxwell vacuum gauge is the best vacuum measurement product to replace the old rotary Maxwell vacuum gauge.