Firma:              Edwards

Modell:            RV8

Kommentar:    Dokumente engl.

Description

The Edwards RV rotary vane pump is shown in Figure 1. Refer to Figure 1 for item numbers in brackets in the following descriptions. The RV pumps are two-stage, oil-sealed, sliding-vane vacuum pumps. The pump has NW25 inlet (4) and outlet (7) ports, a gas-ballast control (5) and a mode selector (11). When the pump is switched off, an inlet-valve seals the inlet and prevents the suck-back of ai and oil into the vacuum system.

The RV3 and RV5 pumps have a retractable lifting handle (3). The RV8 and the RV12 pumps are fitted with a lifting bracket for use with suitable lifting equipment.

An oil-pump delivers pressurised oil to the vacuum pumping mechanism in the RV pump. You can inspect the level and condition of the oil in the oil-box through a sight-glass (8). Two oil filler-plugs (6) and an oil drain-plug (9) are provided on the oil-box.

The pump mechanism is driven directly by a single-phase or three-phase electric motor through a flexible motor-coupling. The motor is totally enclosed and is cooled by the motor cooling-fan which directs air along the motor fins. The pumps are cooled by an additional fan attached to the motor-coupling.

Single-phase motors are fitted with an on/off switch (12) and a thermal overload device. When the motor is too hot, the thermal overload device switches off the pump. The thermal overload device has an automatic reset; when the motor cools down, the device resets and (unless you have incorporated suitable control equipment which must be manually reset: see Section 3.6.2), the motor will restart.

The pump is mounted on a base plate on rubber feet (10). Details of suitable vibration isolators and other accessories are provided in Section 7.

Performance modes and controls

The pump has two controls : the mode selector (11) and the gas-ballast control (5). Six possible combinations of these controls allow for a wide choice of operating characteristics so you can optimize the performance of the puinp for a given application.

Mode selector

The mode selector has two positions; refer to Section 4.1 to select these positions. Throughout the rest of this manual, the following convention is used:

•      The High Vacuum mode is specified by the symbol.

•      The High Throughput mode is specified by thea symbol.

With the mode selector set to High Vacuum mode ‚pressurised oil is fed to the low vacuum stage only. In this mode of operation, the pump provides the best possible ultimate vacuuin.

With the mode selector set to High Throughput mode ‚pressurised oil is fed to the high vacuum and low vacuum stages. In this mode of operation, the pump cart sustain long-term high inlet pressures.

Gas-ballast control

To puxnp high vapour loads, gas-ballast is delivered into the pump to prevent condensation of the vapour carned by the pumped gases.

Air can be introduced to the low vacuum stage through the gas-ballast valve. Alternatively, an inert gas such as nitrogen can be supplied through a suitable extemal valve.

The gas-ballast control has three positions:

•      Closed (position ‘0‘)

•      Low flow (position ‘I‘)

•      High flow (position ‘II‘).

Construction

The pump-shafts and rotors are made of high-grade cast-iron. The pump-body and oil-box are made from cast-aluminium. All surfaces of the pump which are exposed to the pumped gases are free from copper, zinc and cad.mium.

Other materials of construction include fluorocarbon elastomer, nitrile, silicon, chemically­resistant polymers, nickel and stainless steel.

Mechanical data General

Degree of protection (IEC 34-5: 1981)                                      IP44 (single-phase pumps)

                                                                                                 IP54 (three-phase pumps)

Maximum tilt angle                                                                    10°

Motor rotational speed (50 Hz supply)                                      1470 r.min ^-1

Motor rotational speed (60 Hz supply)                                      1760 r.min ^-1

                                                                                                  RV8

Maximum mass, without oil (kg)                                               26.0

Noise and vibration data

Sound pressure, measured at ultimate vacuum 1 metre from 1-phase        3-phase

the end of the pump to ISO 11201, High Vacuum mode,

50 Hz operation                                                                       48 dB (A)        50 dB(A)

Vibration severity: measured at the inlet port to ISO 2372 (1974) Class 1C Class 1C