wilden diaphragm vacuum pump|Application of Diaphragm Vacuum Pump
Its hydrocarbon-free suction chamber makes the diaphragm pump particularly suitable as a backing pump with a turbomolecular pump. Even a two-stage diaphragm pump can achieve an ultimate pressure of approximately 5 hPa. For the backing pump of a turbomolecular pump, this is sufficient. The clean vacuum is particularly suitable for analysis and R&D applications. Because there is no gas ballast, the diaphragm pump cannot pump out water vapor. Even if a small amount of water vapor is desorbed from the wall of the high vacuum equipment, the ultimate pressure of the diaphragm pump can rise sharply. However, some diaphragm pumps are equipped with a gas ballast valve, which operates according to a patented method. To this end, gas is allowed to enter the connecting passage between the first and second stages of the two-stage diaphragm pump, and this is connected to the suction chamber of the first stage through a small hole.
If a larger amount of moisture accumulates and a diaphragm pump without gas ballast is used, a suitable separator or cold trap must be connected upstream to prevent the formation of a large amount of condensate in the pump. But the ultimate pressure will increase.
Diaphragm pumps are different in their ultimate pressure, pumping speed and stability of sucking corrosive gases. The pumping speed of this type of pump is between 3 and 160 l·min-1 (0.25 to 9.6 m3·h-1). A two-stage pump can achieve an ultimate pressure lower than 4 hPa, and a four-stage pump can achieve an ultimate pressure lower than 0.5 hPa. The pumping speed and the achievable final pressure depend on the frequency of the power supply.
The corrosion-resistant gas pump with coated diaphragm and corrosion-resistant casing is suitable for sucking corrosive gases.
The naming method of the pump is l · min-1 to indicate the pumping speed and the number to indicate the number of stages of the pump.
