1.0- GENERAL CONSTRUCTION
1.1 General
This Dry Vacuum pump compresses the incoming gas by means of two screw rotors, having a
profile comprising plurality of curves, i.e. Archimedean curve, Quimby curve and arc, which
rotate smoothly with a certain clearance maintained between each other and the inside wall of
the casings.
The pump is so constructed as to allow no oil to be mixed with the handled gas.
The power of motor is transmitted to the main rotor shaft through a V-Pulley or a coupling
device, and further to the driven rotor shaft through a timing gear.
1.2 Construction
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Screw Shaft
The Screw shaft is made of high grade ductile cast iron. The screw shaft had been through
precision machining done by a numerically controlled special machine. The screw shaft will
have a perfect dynamic balance after machining.
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Timing Gear
The timing gear is the most important part of the screw vacuum pump, and it is necessary for
turning the rotors with a certain clearance kept from each other. The gears tooth surface is heat
treated, and then polished with a special high precision tooth polishing machine for noises
control.
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Bearing
The bearing on fixed side is an angular contact ball bearing and that on free side is a roller
bearing of heavy load capacity. These bearings have been selected as to stand high speed and
heavy service load and to assure clearances between gears and Screws are maintained.
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Shaft Seal
The shaft seals consist of Shaft Lip Seals on Suction side, mechanical Seal and Viton Oil Seal
on Discharge side.
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Oil level Gauge
Oil Level Gauge is located at Front End Cover. Oil should be supplied to the top level of Center
Line. If the oil level is too low, Gear, Bearing and Mechanical Seal will be damaged as a result of
improper lubrication. While pump is not running, check the oil level and/or contamination then.
Refill or change the oil if needed. The oil is splashed over by rotation of timing gear to lubricate
bearings and Mechanical seals.
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