Use and maintenance of oil diffusion pump
Time：2020-09-11 14:30 Click：
The main factors affecting the performance of the vacuum tube furnace assembly diffusion pump
The main factors affecting the performance of the diffusion pump are:
(1) Diffusion pump oil vapor backflow, the solution is to install a cold trap on the vacuum system, which can effectively prevent the oil vapor backflow.
(2) Anti-diffusion of gas molecules, by adding a Roots pump or dual mechanical pump in the high vacuum unit, increasing the pumping speed of the fore-stage pump and reducing the pressure at the outlet of the diffusion pump, which not only reduces the anti-diffusion of gas molecules , And it can also reduce the backflow of oil vapor.
(3) For the cracking and decomposition of diffusion pump oil, use qualified diffusion pump oil to prevent cracking and decomposition.
(4) Diffusion pump is dirty, pollutants are left in the pump and circulate repeatedly. The diffusion pump should be cleaned and the pump oil should be replaced.
Precautions for use
(1) Regularly check the performance of the pump and replace the diffusion pump oil that meets the requirements. Refer to the instruction manual.
(2) The cooling water must be unblocked before heating and during the working process of the diffusion pump. After the heating is stopped, the cooling water must be turned off after the pump oil has been completely cooled. The specific cooling water temperature can be turned off. See the instructions for details.
(3) When the diffusion pump stops working, the inside of the pump should be kept in a vacuum state to avoid oxidizing the pump oil due to release into the atmosphere, so as to extend the life of the pump oil.
(4) Heating can only be carried out when the front vacuum of the diffusion pump is reached, otherwise it will accelerate the oxidation of the pump oil.
(5) The gas to be pumped should be dry, non-corrosive, and dust-free.
(6) If the vacuum suddenly drops during the normal operation of the diffusion pump, first check whether the heater is open, and then check whether there is a leak.
(7) The newly installed diffusion pump cannot reach the ultimate vacuum, so check whether the seal is reliable and the assembly is correct.
(8) During the working process of the diffusion pump, attention should be paid to the working condition of the front stage mechanical pump, because the deterioration of the front stage mechanical pump directly affects the normal operation of the oil diffusion pump.
(9) It is required that the ultimate pressure of the mechanical pump should be one order of magnitude lower than the front pressure of the diffusion pump.
(1) The oil diffusion pump should be placed vertically during installation or maintenance to keep the pump core components in normal working conditions.
(2) When cleaning the parts and pump cavity, first clean with aviation gasoline, then wipe with silk dipped in ether or acetone, and dry at 80-100℃ or blow dry with electric hair dryer.
(3) After cleaning, perform assembly in order. Keep the pump core perpendicular to the pump bottom and concentric with the pump cavity. The nozzle gaps at all levels should be adjusted according to the original requirements.
(4) The rubber seal should be reliable at the connection seal.
(5) If the diffusion pump is not used temporarily, the storage period should be kept in a vacuum state at room temperature to avoid pump oil contamination and parts corrosion, and the remaining water in the cooling water jacket should be blown out.
(6) After long-term work, the performance of the pump gradually deteriorates. Check whether the oil volume is reduced or oxidized. If necessary, increase the oil volume. When replacing new oil, clean and dry.