The Working Principle Of Turbo Pump

Jan 14, 2021

The working principle of a turbo pump is to make gas molecules move in a specific direction by colliding with a moving solid surface. The rapidly rotating fan rotor hits the gas molecules and blows them from the inlet of the pump to the outlet, thereby forming and maintaining a vacuum state. The following is to understand the working principle of the turbo pump.

Most turbo pumps use multi-stage pumps. Each stage has fast rotating rotor blades and stator blades. The pump works like a compressor, which gives energy to the gas instead of expelling it.

When gas molecules enter the inlet of the pump, they are hit by the rotor blades, and the mechanical energy of the blades is transferred to the gas molecules, thereby giving them kinetic energy.

Gas molecules use this kinetic energy to enter the gas transfer holes on the stator. The gas molecules collide with the rotor surface again, and then move outward to the outlet.

When installing the turbo pump rotor shaft through two ball bearings, because of the presence of lubricating oil in the bearings, both bearings need to be placed on the fore-stage vacuum side. The rotor has a large mass and can be supported on one side.

From the perspective of rotor dynamics, the use of hybrid bearing support is more advantageous. Hybrid bearings require the use of a dual bearing concept.

Install an oil-lubricated ball bearing on the shaft end on the front vacuum side. At the other end of the vacuum side, a maintenance-free, wear-free permanent magnet bearing is installed to center the rotor radially.

The brushless DC motor that can support up to 1500HZ rotation frequency is ideal for driving the rotor. This frequency allows the blades to reach the speed required to pump the gas.

The driver is directly connected to the pump and should use 24V, 48V or 72V direct current. Either an external power supply or a power supply unit integrated with the electronic unit of the pump can be used.

The turbo pump can generate a clean vacuum within 10 hPa. Due to its high compression ratio, it prevents oil from entering the inlet area.

A stainless steel cover can be used to make these pumps more suitable for R&D applications. Turbo pumps can also be used to vacuum large vessels, and rotary vane pumps can be used as backup pumps.

If a turbo drag pump is involved, a two-stage diaphragm pump must be used as a backup pump. However, due to the low pumping speed, it takes a long time to empty a large container.