● lubrication of all moving parts
● filling part of the dead volume under the exhaust valve
● sealing the gap between the intake and exhaust channel, and between the vanes and the working
chamber
● ensuring an optimal temperature balance through heat transfer
3.1.2 Cooling
The rotary vane pump is cooled by thermal radiation from its surface, the air current from the two fans
and the pumped gas.
In case of thermally unfavorable ambient conditions, Pfeiffer Vacuum recommends the use of a pump
version with oil/water heat exchanger.
● Air cooling (standard)
● Oil/water heat exchanger (optional)
3.1.3 Gas ballast system
The gas ballast system supplies air to the working chamber of the rotary vane pump periodically at the
beginning of the compression phase. When pumping down vapors, this air prevents condensation within
certain limits in the rotary vane pump. The gas ballast valve affects the final pressure of the rotary vane
pump.
3.1.4 Operating fluid return via the float valve
Function of the operating fluid return
The operating fluid return functions only at an operating pressure of < 800 hPa.
The rotary vane pump is equipped with an operating fluid return as standard. If the operating fluid col-
lected in the operating fluid separator reaches a certain level, a float valve opens and the ejected oper-
ating fluid is returned to the intake port of the vacuum pump.
3.2 Identifying the product
► To ensure clear identification of the product when communicating with Pfeiffer Vacuum, always
keep all of the information on the rating plate to hand.
► Observe the motor-specific data on the motor rating plate attached separately.
3.3 Product features
Pump type
Characteristics
Hena 401
● Nominal pumping speed
─ 50 Hz: 410 m
3
/h
─ 60 Hz: 480 m
3
/h
● Vacuum connection and gas outlet: G 3"
● Operating fluid return via the float valve
● Gas ballast unit with shut-off valve
● Oil/water heat exchanger (optional)
Hena 401 K
As per Hena 401, in addition with:
● Intake flange DN 160 ISO-F for direct assembly of a roots pump
● Base frame
Product description
19/70
