Edwards nEXT400 User Manual

To keep the cleanliness of the vacuum system, we recommend you to vent the pump
bef
ore you set the pump (or vacuum system) to o, when the speed of the pump is
between full rotaonal speed and 50% of the full rotaonal speed. Between this speed,
the rotor spins suciently fast to suppress the back‑streaming of hydrocarbon oil from
the backing pump.
Do not connect the vent valve to the backing pipeline to prevent the contaminaon.
Connect the inlet of the vent valve to the vent gas supply. Refer to Vent gas specicaon
and vent control data on page 27 for the vent gas specicaon.
To do vent, obey one of the methods given in Manual vent valve on page 58 to
Alternave valve connected to the vacuum system on page 60.
4.9.1 Manual vent valve
A manual vent valve is supplied with the pump. Do not open the manual vent valve too
quickly, as it is not possible to precisely control the rate of increase in pressure using the
manual vent valve. We recommend you to open the manual vent valve only aer the
speed of the pump decreases to 50% of the full rotaonal speed.
4.9.2 TAV5 or TAV6 solenoid vent valve
The TAV5 and TAV6 solenoid valves are available as an accessory. Refer to Accessories on
page 99. You can use the solenoid valves as follows:
▪ Use a TAV5 or TAV6 solenoid valve in the place of the manual vent valve on the
pump
▪ Use a TAV5 or TAV6 solenoid valve connected to a convenient ange on the
v
acuum system
If the vent valve is connected to the vacuum system, select a point upstream of
the pump to prevent the back‑streaming of oil from the backing pump.
If you use the TAV5 vent valve, you can hard‑vent the pump only when it is at full speed
(if the vacuum system has a volume of ve litres or more).
If you use the TAV6 vent valve, you can hard‑vent the pump only when it is at full speed
(if the vacuum system has a volume of 10 litres or more).
Install an applicable vent restrictor and vent the pump when it is at full speed or use the
controlled venng opon when:
▪ the volume of the vacuum system is less than 5 litres (when using a
TA
V5 vent valve) or
▪ the volume of the vacuum system is less than 10 litres (when using a TAV6 vent
valve).
Refer to Table: Vent restrictor orice diameter (with atmospheric pressure at the inlet of
the vent valve) for an applicable orice size to be installed to the vent valve for the given
vacuum system volumes to limit the rate of increase in pressure. Refer to Figure:
Maximum allowed rate of increase in pressure during venng: pressure against me
(pump inially at full speed).
04/2022 - ©Edwards Limited
Page 58B80000880_G
B80000880_G - Inst
allaon

Edwards nEXT400 Specifications

General

Brand	Edwards
Model	nEXT400
Category	Water Pump
Language	English