The working principle of oil diffusion pump is similar to that of water vapor injection pump, both of which carry gas by high speed steam jet to achieve the purpose of air extraction. The difference is that the diffusion pump works in the high vacuum area, and its working pressure range is 10-2 ~ 10-6pa. Widely used in electronic, chemical, metallurgical, mechanical, petroleum and atomic energy industries.
Main factors influencing the performance of diffusion pump:
(1) return flow of oil vapor in diffusion pump, the solution is to install a cold trap on the vacuum system, which can effectively prevent the return flow of oil vapor.
(2) the diffusion of gas molecules, the increase in high vacuum unit through a double mechanical pump, roots pump or increasing the backing pump pumping speed, reduce the pressure of air outlet diffusion pump, such not only can reduce the gas molecular diffusion, but also can reduce the oil vapor reflux.
(3) cracking and decomposition of diffusion pump oil. Qualified diffusion pump oil is adopted to prevent cracking and decomposition. (4) the diffusion pump is dirty, and the pollutant remains in the pump for repeated circulation. The diffusion pump should be cleaned and the pump oil should be replaced.
Notes for use:
(1) regularly check the performance of the pump and replace the required diffusion pump oil. Refer to the operation manual.
(2) the diffusion pump before heating and cooling water in the process of work must be ensure unblocked, stop heating, must ensure that the pump oil has to close the cooling water after cooling down, specific to what temperature closed cooling water cooling.
(3) when the diffusion pump stops working, the pump should be kept in a vacuum state to avoid the oxidation of pump oil caused by atmospheric release, so as to extend the life of pump oil.
(4) only when the pre-stage vacuum of the diffusion pump is reached, the heating can be carried out; otherwise, the oxidation of the pump oil will be accelerated.
(5) the gas to be pumped shall be dry, non-corrosive and dust free.
(6) if the vacuum level drops suddenly when the diffusion pump is working normally, first check whether the heater is off the road, and then check whether there is any leakage point.
(7) if the newly installed diffusion pump cannot reach the limit vacuum degree, check whether the seal is reliable and the assembly is correct.
(8) in the working process of diffusion pump, attention should be paid to the working condition of the former mechanical pump, because the deterioration of the former mechanical pump will directly affect the normal operation of oil diffusion pump.
(9) it is required that the limit pressure of the mechanical pump should be one order of magnitude lower than that of the diffuser pump.
(1) when installing or maintaining the oil diffusion pump, it shall be placed vertically to keep the pump core components in a normal working state.
(2) clean the parts and the pump cavity, with aviation gasoline cleaning first, then dip in with silk ether or acetone and scrubbing, and in 80-100 ℃ with dryer for drying or under.
(3) after cleaning, assemble according to the order, keep the pump core perpendicular to the pump bottom and concentric with the pump cavity, and adjust the nozzle clearance according to the original requirements.
(4) connect the sealing place, the rubber seal should be reliable.
(5) if the diffusion pump is not used for the time being, the storage period should be kept in a vacuum at room temperature to avoid oil contamination and corrosion of parts of the pump, and to blow off the remaining water in the cooling water jacket.
(6) after a long period of work, the pump performance gradually deteriorates, and the amount of oil should be checked to see whether it reduces or oxidizes. If necessary, the amount of oil should be increased, and the new oil should be cleaned and dried after replacement.