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.