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• Perfectly suited for conveying acid vapours
and monomers or products that lead to
polymerization when other vacuum technolo-
gies are used

Disadvantages:
• Operating fluids must be treated or correctly
disposed of.

Fig. 5 - Huckepack once-through oil-lubricated rotary vane
vacuum pump

3. Huckepack rotary vane vacuum pumps are
water cooled, thus allowing the operating tem-
perature to be regulated within a certain range.

Huckepack rotary vane vacuum pumps are rotating
positive displacement pumps. The vanes are pla-
ced in slots in a rotor, which rotates eccentrically
in a cylindrical housing. Because of the centrifugal
force created by the rotating motion of the rotor
the vanes slide out of the slots and they come into Fig. 6 - Huckepack once-through oil-lubricated rotary
vane vacuum pump operating principle
contact with the cylinder wall.
This creates spaces with different volumes, which
in turn generate the suction and compression ef-
fect. To reduce friction and improve the seal, oil is Conclusions
continuously injected into the compression cham- All of the vacuum generation technologies discus-
ber. This process takes place in both compression sed here have advantages and disadvantages.
stages before the process gas is discharged toge-
ther with the operating fluid via the outlet and can In most cases, analysis of all
subsequently be removed. Both stages are water
cooled. Versions with once-through water cooling factors leads to a customized
and water circulation are available. “vacuum system, directly tailored
Because the lubricant only flows through the va- to the process requirements
cuum pump once, nearly all liquids with a viscosity
in the range of 150 centistokes (cSt) can be used.
These constantly flush the vacuum pump during There is no single ideal solution for all applications.
operation, protecting it from corrosion and depo- It is therefore important to seek consultation from a
sits. Busch offers vanes made of three different vacuum expert and take into account all important
materials to ensure resistance to most solvents. parameters in the process, starting with process
conditions, process gases and integration into pro-
Advantages of once-through oil-lubricated rotary cess control, through to economic efficiency, safety
vane vacuum pumps: and reliability of future vacuum generation. In most
• High vacuum level cases, consideration of these factors leads to a cu-
• Extremely robust and reliable stomized vacuum system that is directly tailored to
• Easy servicing the requirements.

Uli Merkle

Uli Merkle works for more than 30 years in the sector of industrial vacuum technology. He is Head of
Marketing Services at Busch Dienste GmbH in Germany, a company of the international group of Busch
Vacuum Solutions. He released numerous publications about industrial applications with vacuum techno-
logy. He can be contacted at uli.merkle@busch.de

Impiantistica Italiana - Settembre-Ottobre 2020 95 95