To
meet the varying conditions of operation and possible space
considerations, the following schemes show how the fuel pump can
be selected and sited to suit any particular requirement.
(
i )
Engine driven
The
pump should be driven at approximately half
engine speed. Subject to a maximum driven speed
of 6000 rev/min. The pump should be mounted as low
as possible to achieve maximum positive pressure head
to pump inlet and to provide cooling. Inlet and outlet
of pump must be mounted in a vertical plane, outlet
uppermost, to insure that the built-in non-return
valve functions correctly.
(
ii )
Single motor-driven pump
(
iii )
Twin motor-driven pumps delivering through a two-way
non-return valve.
(
iv )
One motor-driven and one engine-driven pump connected
in series – both with internal or external by-pass
valves (illustration
LSK535).
(
v )
One motor-driven and one engine-driven pump connected
in series with by-pass valve in the engine-driven pump
but no equivalent valve in the motor-driven pump.
(
vi )
One motor-driven and one engine-driven pump connected
in parallel with two non-return valves mounted
separately ( illustration
LSK449)
(
vii )
As
( vi ) but less the non-return valve associated with the
engine-driven pump. This arrangement will suit
installations where the engine-driven pump is situated
high up.