Before the selection of water ring vacuum pump, it is necessary to make clear several basic concepts: in theory, vacuum means that there is no substance in the volume. (there is no real vacuum in practice) generally speaking, the pressure in the container is lower than the normal atmospheric pressure (101325pa), which is called the vacuum condition.
The degree of vacuum indicates the degree of gas thinning under vacuum, which is generally indicated by the pressure value. In practice, there are generally two terms for vacuum degree: positive vacuum and relative vacuum. The value read from the vacuum gauge is called vacuum degree. The value of vacuum degree indicates that the practical value of system pressure is lower than that of atmospheric pressure.
The value indicated from the table is also called the table pressure, which is also called the limit relative pressure in the industry, that is: vacuum degree = atmospheric pressure – positive pressure (atmospheric pressure is generally 101325pa, the limit positive pressure of water ring vacuum pump is 3300pa; the limit positive pressure of rotary vane vacuum pump is about 10Pa). The working pressure of water ring vacuum pump should meet the requirements of process working pressure.
The vacuum degree should be half to one order of magnitude higher than that of vacuum equipment. (for example, the vacuum process requires a vacuum degree of 100 Pa (positive pressure), and the vacuum degree of the vacuum pump selected should be at least 50 pa-10 PA). Generally, if the pressure is required to be higher than 3300pa, the water ring vacuum pump is preferred as the vacuum equipment.
Water ring vacuum pump uses water as working fluid to extract vacuum, and corrosive gas is inevitable in the industrial production process, so we attach great importance to its material selection. As a professional vacuum pump manufacturer, what are the materials used for water ring vacuum pump?
1. Gray cast iron: gray cast iron is a kind of cast iron obtained by the first stage of graphitization. All or most of the carbon exists in the form of flake graphite, and the fracture is gray dark. Therefore, it is named as gray cast iron, inoculated cast iron, rare earth gray cast iron, etc. Gray cast iron has certain strength, but its plasticity and toughness are very low. This property is related to the properties of graphite itself and its existing form in cast iron structure.
It has good shock absorption, can effectively absorb the vibration energy of the machine when making the base or frame and other parts of the machine equipment with gray cast iron, and has good lubrication performance, thermal conductivity and casting performance. It is suitable for castings with complex structure and thin-walled castings because of its good fluidity, small linear shrinkage and volume shrinkage, and its castings are not easy to crack.
2. Spheroidal graphite cast iron: Spheroidal graphite is obtained by spheroidizing and inoculation treatment, which effectively improves the mechanical properties of cast iron, especially the plasticity and toughness, so as to obtain higher strength than carbon steel. Because of its excellent properties, it has been successfully used to cast some parts with complex stress, high strength, toughness and wear resistance. The so-called “replacing steel with iron” mainly refers to ductile iron.
3. Impeller stainless steel: impeller stainless steel material is 304 stainless steel, 316 stainless steel, 316L stainless steel.
4. Stainless steel for overflow parts: pump body, disc and impeller are made of 304 stainless steel, 316 stainless steel and 316L stainless steel.
5. Integral stainless steel: pump body, disc, impeller, pump cover and pump shaft are made of 304 stainless steel, 316 stainless steel and 316L stainless steel; pump body, disc, impeller, pump cover, pump shaft, connecting pipe, upper steam separator, etc.
After understanding the material of water ring vacuum pump, is it very touching to you? For the attention of different materials in use, compare your equipment to understand it in detail.