ProMinent Sigma 3 Basic Operating Instructions Manual page 37

P_SI_0023
Fig. 17: Permissible alignment of the relief
valve
Diaphragm rupture sensor
CAUTION!
Danger of cracking
Cracking of the PVT liquid end can occur if a metal over‐
flow line is connected to the relief valve.
– Never connect a metal overflow line to the relief
valve.
CAUTION!
Danger of the integral relief valve failing
The integral relief valve no longer operates reliably with
feed chemicals having a viscosity of greater than 200
mPa s.
– Only use the integral relief valve with feed chemicals
having a viscosity up to 200 mPa s.
CAUTION!
Warning against leaks
Feed chemical which remains in the overflow line at the
relief valve, can attack the valve or cause it to leak
– Route the overflow line with a continuous slope and
moreover with the tube nozzle pointed downwards -
see Fig. 17.
If the overflow line is fed into the suction line, the bleed
function is blocked.
Therefore lead the overflow line back into the storage
tank.
When operating the integral relief valve close to the
opening pressure, a minimal overflow into the overflow
line can occur.
CAUTION!
Danger resulting from unnoticed diaphragm rupture
If the pump has been ordered with an electric diaphragm
rupture sensor, it still has to be installed.
– Screw the enclosed diaphragm rupture sensor into
the liquid end.
CAUTION!
Warning of unnoticed diaphragm rupture
Only above approximately 2 bar system back pressure is
a signal generated in the event of the rupture of a dia‐
phragm.
– Only rely on the diaphragm rupture sensor with back
pressures of greater than 2 bar.
Or install a back pressure valve and set it to a min‐
imum of 2 bar – if the installation permits this.
Installation, hydraulic
37