When the Roots pump body gas molecules in the gap in the flow of molecular flow. The rotor gap conductance of the Roots pump can be calculated using the Knudsen duct flow guide formula. When Roots pump suction pressure of 133.3 ~ 1.333Pa, the gas molecules in the gap in the flow of molecular flow. Clearance of the conduit can be used Knud pipe Conduction Formula calculation. Where M is Gas molecular weight , T is the temperature, K PK , K PP , K TM , K TNN is the Clausau coefficient of the radial, profiled, fixed and floating fulcrum faces. σ PK , σ PP , σ TM , σ TNN are gap heights (m). Based on empirical data, for a pump with a pumping speed of 0.25-1.5 m 3 / s, K PP = K PK = 0.23. The gap between the end faces is a rectangular channel, and the length of the gap in the direction of the leakage of the rotor is l = r + c (r and c are the radii of the head and the waist of the rotor). inferred for Gap guide C B is calculated assuming that the gas passes through two gap heights σ PK , one gap height σ PP , two end gap heights σ TM and σ TNN , and a gap length D + 2a, as shown in the figure 2 Figure 2 Roots pump clearance around the schematic The gap between the rotor and the selected material, that is Thermal expansion coefficient Different, the rotor material and the rotor peripheral speed. Such as aluminum alloy rotor circumferential speed u = 30-80m / s, steel rotor u2 = 50-100m / s, while the titanium alloy rotor u2 = 80-150m / s, but also cast iron rotor, u2 lower. Refrigeration equipment is mainly used for food refrigeration, all kinds of cargo refrigeration and summer air conditioning. According to the working principle, it can be divided into compression refrigeration equipment, absorption refrigeration equipment, steam jet refrigeration equipment, heat pump refrigeration equipment and electric heating refrigeration equipment. Refrigeration Equipment,Stainless Steel Mini Fridge,Mini Fridge,Supermarket Refrigerator Equipment ShanDong XiMaiD Commercial electrical appliance Co. LTD , https://www.sdcakecabinet.com