NVDM-250 High vacuum Diffusion Pump
The operation of the NVDM-250 diffusion pump is based on the capture and transfer of the pumped gas by a steam jet flowing from the slit gaps of the steam line nozzles towards the outlet flange. The oil reflector of the NVDM-250 diffusion pump is a flange with a cooling tube passing through it, soldered to a cap located in the center of the flange. The NVDM-250 open-type diffusion pump heater is a metal housing with a ceramic base laid in it with a heating element in the form of a spiral made of nichrome wire.
During the operation of the pump, it is necessary to monitor the flow rate and temperature of the cooling water, the level of the working fluid and its temperature. Replacement or refilling of the working fluid depends on the operating mode of the pump (inlet pressure, pumping duration, etc.) and the composition of the pumped medium. Therefore, the time after which the working fluid is replaced or refilled can be from 100 to 1000 or more hours. A large flow rate of the working fluid is observed when the pump is operating in the range of inlet pressures from 6.6 × 10-2 to 13.3 Pa (from 5 ×10-4 to 1 ×10-1 mmHg).
Water at the inlet to the cooling systems of the housing and oil reflector must be supplied with a pressure of no more than 0.5 MPa (5 kgf / cm2) and temperature from plus 4°C to plus 25°C. The recommended cooling water consumption is 100+15 l/h and is regulated by the outlet water temperature, which should not exceed plus 400C. The water drain should be free (with a jet break). Not allowed: operation of the pump without water cooling, exceeding the maximum exhaust pressure of 33.3 Pa (0.25 mmHg) The level of the working fluid during operation, at which the parameters of the pump NVDM-250 are provided, must correspond to min 8mm, max 13mm. The volume of the filled working fluid is 0.55 l
Produced in: Kazan