BE6100
Edition 08/2018
Page 7 of 13
In the case of a G4 execution, the leakage connection
must be piped without back pressure (see drawing 4)
and routed back into the tank in a non-pressurised
state. The connection MUST never be closed or valved
off.
Pressure relief valves
(DBV’s)
Always protect screw pumps against pressure overload,
-do not use screw pumps without pressure relief
valves!
When operating pressure relief valves, it is
forbidden
to operate the pump
above the stated nominal pres-
sure
.
Check the function of the pressure relief valve after
Ionger downtimes.
replace damaged parts if necessary.
Every pressure limiting valve provided by the manufac-
turer is adjusted to a specific pressure and is designed
to meet the requirements of the application.
When using third party valves, adjustable valves or
multiple valves in parallel the following conditions must
be ensured:
1. To protect the motor and pump from overloading the
valves must be set to a specific maximum opening
pressure (valves must be sized to handle 100% of
the pump’s flow rate).
2. When using multiple valves in parallel, the individual
opening pressures of the valves must vary from
each other to avoid multiple valves opening simulta-
neously. Otherwise resonances and vibrations can
occur. Our technical department is glad to advise
you with regards to your particular case.
ATTENTION
Defective pressure relief valves may lead to pump dam-
age.
Excess pressure can also damage other system compo-
nents or cause human injuries.
Do not direct the bypass flow from the pressure relief valve
directly into the pump supply line (Danger of overheating).
Pressure Gauge
Briefly open shutoff valve at the pressure gauge to
check for proper supply pressure, then close again. The
shutoff valve protects the pressure gauge from pressure
surges, which may damage the pressure gauge.
Piping
No pipes or fittings mounted to the pump system should
not put any physical stress on the pump components.
Avoid any unnecessary changes in pipe cross-sections
or in pipe direction (this can cause noise).
The nominal pipe diameters may not be smaller than
the nominal diameter of the pump suction and dis-
charge.
Clean all pipes, fittings and fixtures: remove burr and
welding beads; clean tanks thoroughly.
Flange gaskets must not protrude inside into the pipe.
Make sure that NO metal chips or fines can fall into the
tank after initial pump installation (e.g. drilling holes in
tank lid for name plate mounting, etc).
Air relief valve
The installation of an air relief valve at the highest point
of the discharge pipe is recommended.
Attention
! If the end of the discharge piping is located
below the clean tank in a closed loop arrangement the
clean tank may drain due to the elevation difference.
This can be avoided by installing check valves or air re-
lief valves.
G4 execution
Keep leakage
hole open
also see
section ‘Piping’
Drawing 4
