Dry Pumps

BOC EDWARDS QDP40 & QDP-80 DRY PUMPS:

The QDP pumps operate at pressures between atmospheric and ultimate vacuum with no lubricating or sealing fluid in the pumping chamber. This ensures a clean pumping system without back-migration of oil into the system being evacuated. QDP pumps have enclosed, water-cooled motors and are therefore suitable for applications in clean environments where fan cooling is unacceptable. The QDP pumps are each fitted with a gas system, exhaust-silencer and check-valve. The pump is fixed to the framework by vibration isolators. The framework has castors and leveling feet. The QDP pumps are four-stage, positive displacement rotary pumps in which pairs of  intermeshing rotors (of different profiles mounted on common shafts) are held in correct phase relation by a pair of timing-gears. The timing-gears and the adjacent double-row angular contact ball-bearings, are oil lubricated. The pump shafts and rotors are made from cast-iron. The internal and external shaft-seals on the motor drive-shaft are made of polytetrafluoroethylene (PTFE). Bearings are located on the high vacuum end of the shaft, near to the pump-inlet. These bearings are packed with perfluoropolyether (PFPE) grease.

BOC EDWARDS IQDP-40 & IQDP-80 DRY PUMPS:

The IQDP pump is a four-stage, positive displacement rotary pump in which pairs of intermeshing rotors (of different profiles mounted on common shafts) are held in correct phase relation by a pair of timing-gears. The timing-gears and the adjacent double-row angular contact ball-bearings, are oil lubricated. The low vacuum stage of the IQDP pump has an indirect cooling system, all other stages are air-cooled by natural convection and radiation. In the secondary circuit of the indirect cooling system, coolant circulates around the pump-body by natural convection. In the primary circuit, cooling-water is circulated through copper coils to extract heat from the coolant. In operation, the pump is maintained at a constant temperature by a TCV (thermostatic control-valve) which controls the supply of cooling-water to the primary circuit in the pump. The pump-motor is cooled by water flowing through a cooling jacket which surrounds the motor. The pump-motor cooling circuit is separate from the pump cooling circuit. The cooling-water supply and return pipelines are connected to the pump by connectors on the end of the IQ system. A surface temperature sensor is fitted to the pump-motor. The output of the sensor is monitored by the Sensor Monitoring Module and is used to provide a warning of cooling system failure.