The use of the appropriate model of dry vacuum pump to solve the original mechanical vacuum pump can not solve the two major problems:
One is the pump working medium reflux pollution is pumping container, and this reflux in many cases affect the quality of products, quantity, increase the maintenance cost of equipment.
The second is due to some reaction in the process of the vacuum pump media serious deterioration, so that the pump can not work normally. Our company has a complete range of product models, which can be roughly divided into:
1. Double circular lobe type. Its design and the most popular and widely used roots pump is very similar. In fact, some of the earliest dry pump design ideas were to superimpose roots pumps. This multi-stage design makes the gas path quite complicated, and each stage requires a large flow of nitrogen to dilute and isolate. At the same time, in order to achieve a good vacuum, there are very strict requirements on the clearance of each level. Of course, this design has a relatively low power consumption due to an increased internal compression ratio.
2, internal compression screw type. In addition to the use of a pair of non-equidistant screws, the internal compression screw design and external compression screw design are very similar in principle. The continuous reduction of the volume between the screws causes compression inside them. This design produces internal compression that reduces power consumption to the level of a multistage pump. But in many processes, this internal compression and multistage pump, easy to cause the physical and chemical changes in the pump body gas solidification or liquefaction.
3, combined type (roots + claw). Roots is used to improve the air extraction efficiency at lower pressure and claw is used to improve the air extraction efficiency at higher pressure. Its basic principle and gas path are exactly the same as the loft-shaped design described above. Some manufacturers have changed the final stage to a star design, so that the gas can be divided into five parts in one rotation, just as a three-lobed design can be divided into three parts. Similarly, in many processes, each stage of the modular design requires a larger flow of nitrogen to dilute and isolate.
4. Three-leaf lobed type. The dry vacuum pump is designed in exactly the same way as the double lobed design except that the gas is divided into three parts in one rotation instead of two parts like the double lobed design. The two designs have the same advantages and disadvantages. In order to further reduce power consumption, some manufacturers choose two dc motors in the transmission section, but this will also result in reduced torque and a decreased ability to restart. As with the double lobe design, each stage of the triple lobe design requires a larger flow of nitrogen to dilute and isolate.
5, external compression screw type. Use a pair of equidistant screws. This minimizes internal compression and makes the gas path shortest and easiest. In this way, the gas stays in the dry vacuum pump body for the shortest time. Although this design is relatively high in power consumption due to the reduced internal compression ratio, it shows great stability in many complex semiconductor processes. This single-stage design makes the requirement for nitrogen content very small and simple, which makes it interchangeable in different processes. Nitrogen can even be used in many cleaning processes.
With the expansion of dry vacuum pump application field, suitable type to meet the application needs, play different roles, hope you can choose their own satisfactory products.