Edwards® Vacuum - Turbo pumps and accessories
EXT turbomolecular pumps
EXT75DX compound turbomolecular pump
EXT255DX compound turbomolecular pump
EXT255H compound turbomolecular pump
EXT406PX compound turbomolecular pump
EXT556H compound turbomolecular pump Turbomolecular pump controllers
Edwards Vacuum: EXC controllers
Edwards Vacuum: TIC turbo controller
Edwards: TIC turbo & instrument controller
EXT accessoriesEdwards EXT accessories EXT pump to controller cable EXT ACX air-cooler EXT BX bakeout band EXT PRX10 purge-restrictor EXT TAV vent-valve EXT Vent-port adaptor EXT Vibration isolator EXT VRX vent-restrictor EXT turbo pump spares
EXPT combined outfitsEdwards EXPT 1 &2 pumping stations
STP magnetically levitated turbomolecular pumps and accessoriesEdwards Vacuum - STP turbo pumps STP-XA4503C turbomolecular pump STP-iX455 turbomolecular pump STP301/STP301C turbomolecular pump STP-L301/STP-L301C turbomolecular pump STP603/STP603C turbomolecular pump STP1003/STP1003C turbomolecular pump STPH301C high performance turbo pump STPH451C high performance turbo pump STPA803C "advantage" turbo pump STPA1303C "advantage" turbo pump STPA1603C turbomolecular pump STPA2203C "advantage" turbo pump STP-XA2703C turbo pump STP-XA3203C turbo pump
Edwards® turbo molecular pumps (turbo vacuum pumps) overview, information and definitions
A turbomolecular pump (TMP) A compound molecular pump (CMP) Turbo vacuum pumps - pumping speed Turbo vacuum pumps - quiescent electrical power Turbo vacuum pumps - compression ratio Turbo vacuum pumps - ultimate pressure Turbo vacuum pumps - bearing and suspension Turbo vacuum pumps - rotor Turbo vacuum pumps - motor Turbo vacuum pumps - corrosive applications Turbo vacuum pumps - purge port Turbo vacuum pumps - venting Turbo vacuum pumps - inlet screen Turbo vacuum pumps - cooling Turbo vacuum pumps - scope of supply | Turbomolecular pumps and controllersTurbomolecular and compound molecular pumps and Controllers use advanced technology to facilitate high
and ultra high vacuum.
Key performance aspects
A turbomolecular pump (TMP)
- Multi-stage axial-flow turbine: High speed rotating blades initiate compression by increasing the chance of gas molecules
moving in the direction of pumping
- Turbomolecular pump are optimised
for molecular flow conditions and need an appropriately sized 2 stage
rotary vane pump or an oil free scroll pump exhausting to the atmosphere.
A compound molecular pump (CMP)
- Combed bladed turbomolecular stages with
molecular drag stages on the same rotor
- High critical foreline pressures (typically up to 10 mbar)
- Option to employ smaller backing pumps or dry diaphragm backing pumps
Pumping speed
(volume flow rate)
- Dictated by the rotor diameter, inlet flange
size and rotational speed
- Pumping speed reduces at high inlet
pressures, depending on the backing pump
edwards turbo vacuum pumps (top)
- When inlet pressure increases, both motor power dissipation and pump
temperature rise
- Maximum perpetual inlet pressure dictates the
maximum throughput limit for stable pumping and is dependent on the methods of cooling
- Beyond this pressure, pump rotational speed is reduced as the pump is limited by sensors responsible for temperature
- With water-cooled vacuum pumps, the actual maximum throughput is dictated by the size of
the backing pump
Quiescent electrical power
- Nominal power expended by a vacuum pump operating at full speed with low gas throughput - below 10–3 mbar
- In the course of run-up time/during operation at a high gas
throughput/above critical backing pressure, a vacuum pump's power
dissipation will increase and draw near to the maximum power output for the controller
- Critical backing pressure for conventional
turbomolecular pumps is approx 0.1 to 0.2 mbar.
Compression ratio
- Determined by rotational speed
- The number of pump stages
- Molecular weight of pumped gas.
Compression is greater for heavier gases and is responsible for the requirement for effective suppression, and the reason why the ratio for hydrogen is key for ultra high
vacuum installations.
Ultimate pressure
measured according to Pneurop standards, is the lowest pressure
achieved in the test system, 48 hours after bakeout. The system is
backed only by a two-stage rotary vane pump. Fluoroelastomer inlet
seals are used with ISO-flanged pumps and metal seals are used with
CF-flanged pump models.
Bearing and suspension technologies Technologies of bearing and suspension are generally available:
- Magnetic bearings
- Mechanical ceramic
ball bearings.
- Ceramic bearings, which are lubricated for life by
either grease or oil, have recently replaced steel bearings.
- Silicon nitride ceramic balls are lighter, harder and smoother than
steel counterparts, giving longer life and lower vibration
- Reliability is increased because the ball and race
materials differ, Preventing micro pitting.
- Magnetic
bearings further increase reliability.
edwards turbo vacuum pumps (top)
Rotor technologies - Conventional full stack turbomolecular
(typically 12 stages)
- Compound molecular (combining turbomolecular
and drag stages)
- Stable and rigid rotors for optimum vacuum
performance.
Motor technology - Brushless d.c. motors are common, and are usually available in 24 and 80 volt
versions
- Ref' Edwards® 24 volt pumps:Edwards® TIC line of controllers are
available with integrated instrument controllers.
- Ref' Edwards®80 volt pumps the Edwards® EXC line of controllers get the best out of performance
- Controllers often incorporate a regenerative back-up supply providing
power in the case of electrical supply failure, keeping the ventvalve
closed for several minutes.
edwards turbo vacuum pumps (top)
Corrosive applications - Maximum life and reliability in the harsh process environment
encountered in semiconductor wafer processing applications
- Turbomolecular pumps from the Edwards® STP-C and
STPH-C series serve this application well.
- These Maglev pumps carry magnetic
bearings which perform well in harsh conditions
Purge port - Many turbo vacuum pumps have purge ports used to purge the motor/bearing cavity with an inert gas.
- It is common practice to purge the pump when corrosive and/or abrasive gas mixtures, or gas mixtures contain oxygen content over 20% are pumped
- The Edwards® PRX10
purge-restrictor is recommended to set the purge gas flow rate
edwards turbo vacuum pumps (top)
Venting - It is recommended - in order to maintain cleanliness of vacuum system, that a turbomolecular pump is vented at or above half rotational speed. In other words during the period when rotor speed is quick enough to reduce backstreaming of
hydrocarbons from the backing line
- The vent ports on modern vacuum
pumps are often part way up the rotor stack to ensure maximum cleanliness even
with fluoroelastomer sealed vent-valves. Each Edwards® pump is usually supplied with a
manual vent-valve. Care must be taken not
to open this manual vent valves too quickly, vacuum pump bearing life may be affected
- Small volume
vacuum systems: Rate of pressure rise will be pronounced over that of a large volume for any vent flow rate, hence the possibly necessity to restrict the vent gas
flow. Edwards® offer their VRX range of vent restrictors for Edwards® EXT pumps
edwards turbo vacuum pumps (top
|