Vogelsang VX Series, Manual

Page: 71 / 202

Rotary lobe pump
Operating instructions
VX100Q, VX136Q..QD..QDM2, VX186Q..QD..QDM2, VX230Q..QD
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7.2 Buffer chamber assemblies
7.2.1 Pressurisable buffer fluid tank
The pressurisable buffer fluid tank (hereinafter “tank”) with manual air pump ensures a constant and defined
buffer chamber pressure (buffer chamber pressure = tank pressure).
The tank is for safely monitoring the buffer chamber.
Installing the tank
1. Remove the plug from the buffer chamber and fill it to
the maximum level.
2. Screw the tank directly into the cast body of the buffer
chamber. Fill the tank about one quarter full.
3. With a manual air pump or via a compressed air supply
outlet, set the desired tank pressure.
Tank pressure
The tank pressure should be about 0.5 bar higher than the
average pressure in the pump.
Tank pressure = 0.5 bar + (pressure on the suction side +
pressure on the discharge side) / 2
Example
One pump primes with 0.4 bar suction and presses with 2.0
bar overpressure.
Pressure on the suction side:
– 0.4 bar, pressure on the
discharge side: 2.0 bar
Tank pressure = 0.5 bar +
2
) bar 2 bar 4 , 0 (
 
= 1.3 bar
In this example, the tank pressure is 1.3 bar.
Independently of this, the tank pressure with a single
mechanical seal must be max. 5 bar and max. 10 bar with a
double mechanical seal.
Rotary lobe change
Before changing the rotary lobes, depressurise the tank
pressure and prime it again after changing.
Buffer fluid tank with pressure gauge, filling
valve and manual air pump
Open buffer fluid tank
Trouble indication
Trouble at the sealing system after the running-in period may
be displayed:
•
as a result of severe contamination of the buffer fluid in
the tank
•
as a result of buffer fluid escaping (tank is empty)
•
as a result of increasing buffer fluid (tank is full)
Topping up buffer fluid
1. Drain the pressure from the buffer chamber via the air
valve.
2. Loosen the upper screw connection of the upper
housing (hold the union nut tight so that the lower screw
connection does not come loose).
3. Top up the buffer fluid in the tank
4. Readjust pressure
Filling/draining buffer chamber
B draining, 6 hexagon head screw plug
Fig. 16 : Buffer chamber monitoring