2XZ Series Double Stage Rotary Vane Vacuum Pumps

2XZ series rotary vane vacuum pump is double stage high speed oil sealed rotary
vane vacuum pump (hereinafter referred it as "the pump" for short). Its pumping
principle is same as that of 2X type pump. Rotors are eccentrically mounted
within the cylindrical housing of the stators and vanes are fitted freely
inside the respective slots of the rotor.

When the rotor rotates at high speed, vanes in the rotor slot are urged
outwards by centrifugal force as well as by spring force so as to keep close
contact at their tips with the stator wall throughout rotation. Thus the inlet
port and outlet port on the stator are separated by them. The volume of the
space leading to the inlet port expands progressively and periodically with gas
filling the space through inlet pipe, meanwhile the volume of the space leading
to the outlet port diminishes progressively and periodically to compress the
gas previously sucked.

By means of gas pressure and oil pressure exhaust valve on the outlet port is
opened to expel gas out of the pump through the valve, then vacuum is obtained
at the intake side of the pump. Fig 1 shows the working principle of a single
stage pump. Double stage pump is the arrangement of two single stage pumps in
series. When the intake pressure is higher, both stages of the pump may exhaust
simultaneously, while at lower suction pressure gas is first expelled out from
first stage to second stage, then from second stage exhausts to the open air.

2XZ type pump is equipped with gas-ballast valve. Its function is to fill the
exhaust space with certain amount of air, when the valve is open, so to reduce
the proportion of the partial pressure of vapor in the total discharge
pressure.

As the partial pressure of vapor is lower than that of the saturated vapor
pressure corresponding to the working temperature of the pump, vapor can be
discharged from the pump with the filled air in order to avoid condensation of
vapor in the pump oil and to prevent oil from emulsifying by the condensed
vapor so as to prolong the useful lift of oil. However the ultimate vacuum of
the pump shall drop, and the temperature of the pump shall rise when the gas-
ballast valve is open.

2XZ type pump has the outstanding advantages of small size, light weight, low
noise and easy to star etc. Besides, devices to prevent oil from sucking back
and leakage of oil from axle sealing to contaminate environment are also
provided.


Characteristics
Simple voice, simple structure, high efficiency
Extreme high vacuum, pumping speed large
Use gas ballast valve, can be able to pump condensable gas, such as water vapor
Pressure oil circulating system
Automatic fuel oil returning check valve
Applications
The pump is one of the basic equipment to exhaust a sealed vessel. It can be
used either independently and can also be served as fore-pump for booster pump
diffusion pump and molecular pump or as holding pump for a vacuum system and as
a pre pump for titanium pump.
The pump is allowed to work continuously for long time under the condition that
atmospheric temperature of 5ºC-40ºC and intake pressure below 1300Pa. While the
pumped gas contain relative humidity more than 90%, gas-ballast valve should be
opened.
With the inlet port widely opened to atmosphere, the pump is not allowed to
work more than one minute.
The pump is not suitable for pumping over-oxidized, poison, explosive and
corrosive gas, gas containing particulate dust as well as gases which react
chemically with the pump.
It can be used for electric vacuum devices and thermos manufacturing, vacuum
welding, printing, plastics, refrigeration equipment repair, medical analysis
device industry, solar energy industry, electric light source industry, vacuum
furnace industry and scientific research unit, instrumentation, etc. It is more
suitable for laboratory use because of its advantages like small size, light
weight and quiet operation etc.

Minimum Order: 1 sets

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