Why should screw vacuum pump use nitrogen? This is the related question we will talk about in this issue. The answer to this question is in the following elaboration:
1. The purpose of injecting nitrogen into the screw vacuum pump is to form a weak protective gas film on the inner wall of the vacuum pump. The nitrogen pressure should not be too high or too small, which will affect the vacuum pumping effect and increase energy consumption; too small may lead to the formation of no protection effect.
2. The pump pumping corrosive gas will use nitrogen, which will purge the pump to delay the corrosion of corrosive gas to the pump.
3. Some gases used in vacuum coating process have corrosive effect on screw vacuum pump, so this kind of pump will be used. But the nitrogen in the wall is separate from the pump.
4. How many units of nitrogen can be flushed to give the color they need. Some colors use acetylene. In practice, most of them use argon.
5. Gas tight, dilute process gas. Reduce corrosion and process adhesion.
6. It is difficult for nitrogen to react with the outside world without a certain temperature, pressure or catalyst. Therefore, in the process of screw vacuum pump system cleaning, the use of nitrogen purging, more safe and reliable.
7. The adsorption heat of nitrogen is small and the adsorption time is short. When nitrogen is adsorbed on the wall surface of dry vacuum system pump, it will be easily pumped away. The nitrogen purge in vacuum system cleaning makes full use of this characteristic. In vacuum coating, nitrogen molecules will first adsorb on the wall of the vacuum system after purging and cleaning the vacuum system with dry nitrogen.
Because the adsorption sites on the surface of the vessel wall are fixed, other molecules such as water molecules will be reduced after being filled with nitrogen molecules. Therefore, the whole pumping time of the vacuum system will be greatly reduced.
How to judge the quality of filter element of screw vacuum pump?
How to judge the quality of filter element of screw vacuum pump? This is what we are going to talk about in this issue
1、 Look at the thickness of the core framework of the filter element
Generally, the internal and external skeleton thickness of screw vacuum pump filter element is between 0.8mm-1.5mm, but some businesses reduce the framework to 0.3mm-0.5mm in order to reduce the layer cost. There is no difference in appearance, but it seriously affects the compressive capacity of the filter element.
2、 Look at the material of filter element
The main filter material of air filter element of screw vacuum pump is filter paper. The inferior filter paper used in fake filter element can not prevent dust from entering the engine, thus affecting the normal operation of the engine. Generally, the color of the filter paper of the excellent vacuum pump filter element is uniform, and the paper surface is relatively flat; while the color of the filter paper of the inferior filter element is not uniform, the paper surface is hairy and the texture is very poor.
3、 Look at the gel of the filter element
At present, the structure of the filter element of screw vacuum pump is generally composed of filter paper and rubber, and the glue of the true filter element is different from that of the false filter element. The rubber of genuine filter element has good texture and elasticity, while the rubber of counterfeit filter element is soft and poor in texture. It is easy to identify the method is to fold the air filter element in half. After loosening, the excellent filter element will quickly recover to its original state. Due to the rubber texture problem, the false vacuum pump filter element has poor adhesion with the filter paper, and the mark in the middle of the fold is obvious.
The main content of this issue is these, I hope you know more about screw vacuum pump.