Pump selection is a necessary link in the purchase process. It requires a deep discussion and exchange between the purchaser and the technical personnel according to the specific working conditions, so as to determine the type selection and material of the vacuum pump finally. When purchasing or selecting the liquid ring vacuum pump, attention shall be paid to:
How to understand selection of liquid ring vacuum pump
The type of pump is mainly determined by the air volume, vacuum degree or exhaust pressure required by the work. When roots vacuum pump works, it is expected to work in the high efficiency area as much as possible, that is, in the area of critical vacuum degree or critical exhaust pressure.
When preventing working in the vicinity of maximum vacuum or maximum exhaust pressure. Working in this area, not only the power is very low, but also the work is very variable, so it is difficult to have oscillation and music. As for the vacuum pump with high vacuum degree, when it is working in this area, cavitation often occurs. The more marked sign of such phenomenon is that there is no music and vibration in the pump.
Cavitation will lead to the damage of vacuum pump body, impeller and other parts, resulting in the pump can not work, the selection of liquid ring vacuum pump knowledge! If the vacuum degree or exhaust pressure is high, the single-stage pump is often unable to be full. Perhaps, it is required that the vacuum pump is still without large air volume under the condition of high vacuum degree.
That is to say, the function curve is required to be relatively flat when the vacuum is high, and two-stage pump can be selected. If the vacuum degree is required to be more than – 710mmhg, liquid ring atmospheric pump or liquid ring roots vacuum unit can be selected as vacuum pumping installation and disassembly. If only vacuum pump is used, single-stage pump is better than force. Because of the simple structure of single-stage pump, it is difficult to control and protect.
And it has good cavitation resistance under high vacuum. If it is only used for the compressor with large air volume, the double-stage pump specific force is suitable. Because of the large air volume, small volume and light weight of the two-stage pump, the radial force can achieve active balance, the shaft can not be difficult to crack, and the service life of the vacuum pump is long.
Vacuum pump mechanical safety requirements
According to GB / t8196, exposed moving parts shall be equipped with protective devices for preventive protection. If the protection device can prevent the test manipulator specified in en60529 from contacting with moving parts, it can be considered that the protection effect of the protection device is sufficient. All accessible edges and corners shall be designated as areas to avoid injury. If protection is achieved only after the complete installation of the vacuum system, temporary protection measures shall be provided during the installation of the vacuum pump (for example, if the population of the vacuum pump can reach the mechanical parts of the pump, the population of the pump shall be covered).
In the process of using vacuum pump equipment, the vacuum parts should have enough strength to withstand extrusion. Where such hidden dangers cannot be eliminated, anti pressure devices shall be set to control the ejected objects. The exhaust filter shall have enough capacity to ensure the safe operation of the vacuum pump under the condition of maximum air extraction. Measures shall be provided to ensure that the filter will not cause the vacuum pump population pressure to exceed its maximum allowable working pressure in case of saturation or blockage. If the debris accumulated at the pump exhaust port or in the vacuum system cannot be avoided, an exhaust pressure monitoring device or a pressure regulating valve shall be provided.