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Dec. 10, 1946.
c. A; PUGH ETAL
2,412,289
PUMP HAVING BYPASS WITH SPEED-SENSITIVE AND PRESSURE—HESPONSIVE_ CONTROL
Filed May 16, 1942
2 Sheets-Sheet 1 .
CYRIL A. PUGH X
1% Doucms G. BOOTH
Dec. 10, 1946.
c. A. PUGH ETAL_
2,412,239 ‘
PUMP HAVING BYPASS WITH SPEED-SENSITIVE AND PRESSURE-RESPONSIVE CONTROL
Filed May 16, 1942
2 Sheets-Sheet 2
Cm”. A. PucH 1'
Dave us C. BOOTH
luvznrok:
Patented Dec. 10,1946
2,412,289
UNITED STATES PATENT OFFICE‘
2,412,289
PUMP HAVING BYPASS WITH SPEED-SENSI-_
TIVE AND ‘PRESSURE-RESPONSIVE CON
TROL
Cyril Alphonso Pugh and Douglas Gerhard Booth,
Ili'ord, England, assignorsto ‘The Plessey Com
panyLimited, Ili'ord, Essex, England, a British
company
Application May 16, 1942. Serial No. 443,186
‘
In Great Britain April 7, 1941
2 Claims. (Cl. 103-12)
2
This application corresponds to the application
of Cyril Alphonso Pugh, Douglas Gerhard Booth,
and The Plessey Company Limited, Serial No.
tion;
4,635/41, which was ?led in Great Britain on
April 'I, 1941, and which was issued as British
ure 1;
Patent'No. 549,205, complete speci?cation accept
ed Nov. 11, 1942.
of the apparatus essential to the present inven
Figure 2 is a section on the line 2-4 of Fig
'
" Figure 3 is‘ an end view looking from the right
of Figure l, and
_
Figure 4 diagrammatically represents the posi
This invention consists in improvements in or
tion of the valve in relation to the main and by
relating to ?uid supply and control systems for '- pass conduits.
use in aircraft and is especially applicable to sys 10
As diagrammatically illustrated in Figure 4, the
tems for supplying liquid fuel under pressure to
pump is represented at to as having an inlet H
an aircraft engine or other fuel-consuming
and an outlet ii. A port i 3 directs pressure ?uid
means.
1
from the pump outlet towards one face of a valve
One object of the invention is to provide a
M which controls a branch passage it connect
supply of fluid at a pressure which varies both 15 ing the inlet with the outlet of the pump as a
. with‘the speed of the engine or rate at which
by-pass return to the pump itself.
the ?uid is consumed and also with atmospheric
Inthe construction illustrated in Figures 1 to‘
pressure.
.
3, theapparatus is contained in a main casing
According to the present invention a ?uid-sup
56 having a cover I‘! bolted thereto as at E8.
ply and control system comprises in combination 20 Within‘ the "casing it is a. positive displacement
a pump driven by an engine or other fuel con
pump represented as a, whole by the reference
suming means, which pump delivers ?uid at ex
numeral it, the rotor of the pump containing
cess ?ow and has a .by-pass between the inlet
vanes which revolveabout a shaft 2d. The cas
and outlet, valve means controlling this by-pass,
ing- of the pump provides an inlet, also indicated
a speed-sensitive device driven incompany with 26 by the reference numeral ii in the section shown
the pump, and pressure responsive means which
in Figure 2, and an outlet 82, these two passages
varies automatically in e?ective length and, con
stitutes an‘ operative connection between the
speed-sensitive device and the by-pass valve
bearing numbers corresponding to the reference
numerals employed in Figure 4.
Parallel with the shaft 20 is the valve I4 in
means to vary the e?ective length 01' that opera 30 . the lower part 01 casing it and this valve controls
tive connection, whereby the force with which the
the by-pass passage it as already described, the
speed-sensitive device acts upon the valve isv
formation of the inlet passage H in thecasing
varied by changes in pressure to which the pres
being'such as to a?ord communication with the
sure-responsive means is subjected. /
by-pass passage is as indicated in dotted lines in
For a given range oi! speed and a given'range 35 Figure 2. 0n the outlet side of the pump the
of atmospheric pressure, the mechanism serving
outlet passage incasing I8 is formed also as
to actuate the valve or valves controlling the vby
clearly shown to communicate with the passage
pass is arranged to operate according to a pre
‘
I3 leading to the outlet I2.
7
determined relationship on the one hand between
The pump I9 drives a centrifugal speed respon
the delivery pressure of the pump and the speed, 40 sive device of which the main spindle is repre
and on the other hand between the delivery pres
sented at 2| and the centrifugal members are
sure and the atmospheric pressure.
shown as comprising bellcrank arms 22, 23 piv
Other features of the invention consist in the
oted at 24 in a disc integral with spindle 2|.
provision of means which may be adjustable for
Arms 22 bear on a plate 25 that is mounted by
limiting the travel of the governor device to main 45 means of a. thrust bearing 26 on the end or a
plunger 21 which itseli at its opposite end is en
tain a predetermined pressure, and also in pro
gaged with one arm of a control lever 28 pivoted
viding means to correct the pressure according to
at 28 centrally of its length in cars extending
variations in temperature, for instance atmos
inwardly from the cover II. The other end of
pheric temperature.
._
'
'_
50 lever 28 bears against the end of a tubular mem
In order that the invention may be more clearly
ber 30 which can slide endwise on a fixed or ad
understood, a preferred example will now be de
justable rod ii in the same manner as the
scribed with the aid oi.’ the accompanying draw
plunger 21, which also is tubiuar, and mounted
ings, in which-,
to slide ‘on a ?xed or adjustable rod 32. The
Figure 1 is a central section through those parts 65 tubular member II is integral with one end of a
2,412,289
’
'
3
.
'
.
4
or other iuel-consunnng means, which pump de
livers ?uid at excess ?ow and has a by-pass be
tween the inlet and outlet, valve means control
closed bellows ‘I, the other end or which is con-,
nected at “to the by-pass valve It. A com
pression spring 85 is located within the bellows
and acts on the ends of the latter to provide a
ling said byepass, a speed-sensitive device driven
in company with the pump, and pressure-respon
sive means which varies automatically in e?ective
length and constitutes an operative connection
between the speed-sensitive device and said valve
spring loadins against atmospheric pressure.
In operation, thev output pressure of the pump
ll acts on the by-pass valve is with a tendency
to open this valve. Under normal conditions of
operation, the valve will be more or less open
means to vary the eii'ective length or that opera
passing the excess delivery of the ?uid back to 10 tive connection, whereby the force with which the _
speed-sensitive device acts upon the valve is varied
the suction side of the pump as can be clearly
- by changes in pressure to which the pressure-,
seen from a study of the diagram, Figure 4. The
responsive means is subjected, said pressure
delivery pressure from the pump is controlled by
responsive means including a collapsible device
the force with which the speed responsive device
resiliently controlled to provide a loading for the
acts upon valve It and this pressure will rise
v ve.
'
with increasing speed of the speed responsive de- '
2. A ?uid-supply and control system compris
vice until a predetermined stop position is
ing in combination a Dump driven by an engine or
reached.
other fuel-consuming means, which pump delivers
In the case of a decrease in atmospheric pres,
sure acting upon bellows it, the'bellows lengthen 20 ?uid at excess flow and has a by-pass between the
inlet and outlet, valve means vcontrolling said by- _
pass, a speed-sensitive device driven in company
with the pump, and pressure-responsive means
under the action of the compression spring 35.
This spring reacting through the-valve on the
delivery pressure moves the centrifugal members
of the speed responsive device to a position of
which varies automatically in e?ective length and
shorter effective. radius so that the controlling 25 constitutes an operative connection between the
speed-sensitive device and said valve means to
force produced by the said device is decreased
vary the eiiective length of that operative con
and the valve is thus permitted to open under the
nection, whereby the force with which the speed
action of the delivery pressure on the valve and
sensitive device acts upon the valve is varied by
so reduce this pressure. The converse oi.’ this
, will, of course, occur with an increase in, atmos 30 changes in pressure to which the pressure-respon
sive means is subjected, said pressure-responsive
pheric pressure.
.
means including a. collapsible, resilient device, the
In order to correct the ?uid pressure for varia
resilience of which provides a loading for the
tions in temperature the bellows may be gas ?lled.
We claim:
1. A ?uid-supply and‘ control system compris
ing in combination a pump driven by an engine
valve.
3,5
>
7
CYRIL ALPHONSO PUGH.
DOUGLAS GERHARD BOOTH.
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