V-line 899x.xxx
USER’S MANUAL
52
13.1.2.
Installation at the filling station with overground (aboveground) tanks
A safety relief check valve (PZV), opening at vacuum pressure Hs = – 0,03 MPa max. induced by
dispenser pump, shall be installed in the suction piping (PT) connecting the dispenser and the
storage tank. The check valve (PZV) is usually connected to the suction fitting located on the tank
cover. The check valve prevents permanent supply of stored fuels into the pumping monoblock
when the dispenser is out of operation.
The pumping monoblock of dispensers (P 640 type) is designed with air separator permanently open
to the deaerating chamber formed by the space in the monoblock body and the space of the
monoblock cover. There is a hole in the upper wall of the cover with integrated DN 6 adapter for
connecting the air outlet pipe (OT).
To eliminate the overfilling of the deaeration chamber of the pumping monoblock and discharging of
fuel into the interior of the dispenser and consequently into its close area in case of the leakage or
blocking of the check valve flap when the dispenser is out of operation, it is necessary to connect
the separator outlet of the pumping monoblock to the storage tank. This connection shall be carried
out by means of a tube (OT) min. 8 x 1 (DN 6) connected to the tube adapter DN 6. The tube
adapter with the gasket is screwed into the opening M 12 x 1,5 in the upper wall of the monoblock.
The tube outlet mouths in the tank above the level of the stored fuel. The connection shall be
carried out by means of the tube adapter DN 6 screwed into the tank cover (tapped hole M 12 x 1,5
in the tank cover shall be made).
Closing the outlet opening of the pumping monoblock separator is not allowed. Accumulation of
separated air or fuel vapours and their sequential compression in this closed space of the pumping
monoblock or a change in the fuel volume owing to the ambient temperature increase can induce
excessive pressure in the hydraulic system. Thus blockage of the fuel dispensing or another defect
could occur.
A stop-valve (UV) of relevant nominal inside diameter shall be installed in the suction piping as close
to the dispenser as possible (e.g. in the shaft close to the dispenser).
Piping from air separator (OT
– min. DN 6 – 8 x 1) install in the tank area above the level of storage
fuel.
Scheme of the fuel dispenser installation
– see fig. 2, 3 and 4.
Fig. 2 - Fuel dispenser connection to
the overground tank
PT – fuel suction piping
VR – return piping for vapour recovery
(DN min. 20)
OT – piping from air separator (min. DN 6)
PZV – return valve (Hs = -30 kPa)
UV – stop-valve
DN – inner diameter of suction piping (mm)
L – lehgth of suction piping (m)
