Edwards EH Mechanical Booster Pumps
The EH mechanical booster pumps feature the unique hydrokinetic
drive, providing an efficient power transmission with benefits in
economy, performance and compactness. The hydrokinetic drive
provides the following features:
- Pump down times cut by 50%, when compared with direct drive pumps
- No bypass lines or pressure switches required
- Universal voltage motors
- Reduced capital and operating costs
- Air cooled motors - with water cooled options
- Quiet, minimum vibration
The EH mechanical booster pumps, based on the simple Roots principle, remain the favorite pumps for applications where high
pumping speeds over 3000 m3h-1 / 1776 ft3min-1 are required in the
pressure region of 0.01 to 50 mbar / 0.0075 to 37.5 Torr. These
pumps must always be backed by another pump which can deliver
against a high pressure differential to atmospheric pressure.
Operating at relatively low pressures, the mechanical booster pump
is not exposed to the same concentrations of corrosive process
media as is the backing pump, which makes it highly reliable.
High Performance Pumping Mechanism
The EH has a high quality, oil-free pumping mechanism. This offers:
- Quiet, vibration free operation
- Rugged and corrosion resistant
- Advanced shaft-seal technology - no oil contamination of process chamber
The corrosion resistant pumping mechanism is manufactured from
high grade cast iron. The proven shaft-seal arrangement ensures that
no oil enters the pumping stator, and the absence of internal and
external by-pass lines and valves which may corrode or stick
minimizes maintenance requirements.
The design of the shaft seals is optimized to ensure that no lubricants
can migrate into the pumping mechanism. This maintains booster
pump performance in applications which demand the highest
standard of cleanliness. In addition, this prevents the build-up of
trapped particles on the rotor lobes and end-faces which have very
The dynamically balanced rotors and precision ground gears
contribute to the smooth, quiet operation of the pumps, as demanded
by manufacturers of advanced technology equipment.
Broad Application Coverage
EH mechanical boosters are available to cover a broad range of
industrial and chemical process applications.
Industrial EH boosters are safe to handle non-flammable gases and
vapors within the normal operating parameters of the booster.
ATEX classified EH boosters are annotated with the suffix "T3" or
- EH boosters may be supplied with ATEX classification either as part of a pump system or stand-alone, on application. Please consult Edwards.
- ATEX compliance is typically specified for use in Europe, but may also be required in other areas.
ATEX compliant EH boosters are suitable for operation in ATEX systems rated as follows:
All of the EH1200C, EH1200 T160, EH2600C, EH2600 T3, EH2600
T160, EH4200C, EH4200 T3 and EH4200 T160 chemical EH pumps
are fitted with flameproof motors:
- Pumps suitable for 50 Hz operation are fitted with a flameproof
motor approved to EEx d. Gas Group IIA, lIB, Temperature Class
- Pumps suitable for 60 Hz operation are fitted with a flameproof
motor approved to CSA, Division 1 area, Gas Class I Group C & D,
and Dust Class II Group F & G, Temperature Class T3C.
Internal and External Classifications
(Ex) II 2G c IIB T3 or
(Ex) II 2G c IIB T160
The notations used in these ratings are as follows:
|Specifies that the chemical EH pump can be used in a potentially explosive atmosphere
Equipment Group II
Equipment Category 2 (gas)
Suitable to pump gas group IIB
Gas auto-ignition temperature
For equipment category 1 (gas) consult Edwards.
Gas Auto-Ignition Temperature
The temperature classifications applied to the chemical EH pumps
relate to the auto-ignition temperature of flammable materials that can
- The EH1200C, EH2600C, EH4200C and chemical EH pumps that
have a T3 classification are suitable for pumping flammable
materials that have an auto-ignition temperature greater than
- Chemical EH pumps that have a T160 classification are suitable for
pumping flammable materials that have an auto-ignition
temperature greater than 160 °C.
Explosion proof boosters are annotated with the suffix "C".
- EH boosters may be ordered with explosion proof motors either
individually, or as part of an explosion proof system.
- Explosion proof is generally applicable in N. America and the rest
of the world (excluding Europe).
Explosion-proof boosters will be supplied fitted with an explosion-proof
motor (suitable for 60 Hz operation) approved to CSA, Division
1 area, Gas Class I Group C & D and Dust Class II Group F & G,
Temperature Class T3C.
EH Pumps with Hydrokinetic Drive
EH booster pumps have a unique and patented hydrokinetic fluid
drive, which couples the motor to the pumping mechanism. The
hydrokinetic drive offers the following advantages:
- Pump down times cut by up to 50%
- Reduced capital and operating costs
- No pressure sensors, by-pass lines or valves
- Can operate continuously at all pressures - when used with a backing pump
EH booster pumps have universal voltage, air-cooled motors and are
available with effective pumping speeds of up to 4140 m3h-1 /
2440 ft3min-1. The pump bodies of the EH1200, EH2600 and EH4200
pumps are water-cooled.
Two versions of each EH booster pump are available, with different
oils used for the lubrication of the seals and gears. The standard
version uses mineral oils, such as Ultragrade 20. The alternative
version has PFPE (perfluoropolyether) oils and is suitable for
applications where oxygen or other reactive and corrosive gases are
Pump-Down Times cut by up to 50%: The hydrokinetic drive allows
the booster pump to be started at the same time as the backing pump
(at atmospheric pressure) as it prevents motor overload. The EH
booster pump therefore assists the pumping process from the start of
pump-down. In comparison pumping systems with conventional,
direct drive mechanical booster pumps (where the booster pump is
switched on when the chamber pressure has been reduced to,
typically, less than 10 mbar / 7.5 Torr), the total evacuation time can
be reduced by as much as 50%.
Automatic Overload Protection: The hydrokinetic drive automatically
varies the rotational speed of the pump. This protects the motor from
overload, prevents over-heating, and allows the pump to operate with
high pressure differentials. Consequently, EH booster pumps are not
damaged by sudden increases of inlet pressure and even by the entry
of solid debris into the pump.
Important Cost Savings: When you use EH mechanical booster
pumps, you save money on installation and operation. Your capital
costs are reduced as you do not need valves, by-pass lines and
pressure switches, and you can use a smaller backing pump than
with conventional drive booster pumps. Operation costs are reduced
because EH booster pumps have smaller motors than direct drive
pumps and, when operating at full speed, they use only a fraction of
the rated power.