Bareshaft (Belt Drive) Booster Pumps; Direct Drive Booster Pumps (With Shaft-Mounted Motors); Integral Bypass Valve (Model 615 Pumps Only); Oxygen And Reactive Gas Service - Edwards 900-607-MH05 Instruction Manual

1.7

Bareshaft (belt drive) booster pumps

The booster pumps have been designed to withstand loading from standard V-belts, for standard operation from 800
to 3600 r min-1 (r.p.m.). The loads induced into the drive shaft depend on the power applied to the shaft. Edwards
specifies a minimum pulley diameter for the drive shaft based on motor power. You must never use a pulley with a
smaller diameter than those specified in this manual. Refer to Table 12 for specific details on pulley diameters.
Edwards can provide booster pumps and motors sized for most applications.
1.8

Direct drive booster pumps (with shaft-mounted motors)

Direct drive eliminates the tension loads associated with belt drives. The direct drive booster pump consists of a
standard booster pump, coupling, motor support, and C-face (NEMA) or D-flange (IEC) motor. Optional variable
frequency drives are available from Edwards to improve performance on booster pumps without bypass valves.
Consult Edwards for application information. Various voltage, frequency, speed and power motors are available.
Large power motors (> 22.37 kW, 30 h.p.) cannot be supported by a motor support alone.
1.9

Integral bypass valve (model 615 pumps only)

Model 615 booster pumps can be supplied with an integral bypass valve for operation from atmospheric pressure. The
bypass regulates the amount of compression across the booster pump body. The limiting speed for the bypass booster
pump is 3600 r min-1 (r.p.m.). The bypass valve regulates the pressure differential across the booster pump to 7.9 x
103 Pa (79 mbar, 60 Torr). Maximum discharge temperature and maximum temperature rise are the same as for the
standard 615 booster pumps. Under some operating conditions, it is not possible to operate the bypass booster pumps
continuously because of the heat generated from gas compression. These conditions depend on chamber size and
backing pump speeds. Consult Edwards if pump-down exceeds 45 minutes. Refer to Figure 3 detail E for a cross-
section view of a bypass booster pump.
1.10

Oxygen and reactive gas service

Edwards can prepare bareshaft booster pumps for hazardous gas duties (where pumped gases could react with the
hydrocarbon lubricants in standard pumps). When prepared for hazardous gas duties, the booster pumps will be free
of hydrocarbons and must be used with inert lubricating oil which will not react with the hazardous gases pumped.
You must take special care when operating booster pumps on oxygen pumping duties: refer to the "Vacuum pump
and vacuum system safety - chemical & industrial systems" publication (Edwards Publication Number P400-40-100).
© Edwards Limited 2008. All rights reserved.
Edwards and the Edwards logo are trademarks of Edwards Limited.
S900-01-880 Issue C
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