US2238502A - Pumping apparatus - Google Patents

Description

April 15, 1941. .N. s. M UIR- ETA'L- 2,2 8,502"

PUMPING APPARAT S Filed Jan. 17, 1940 A ltomey I Patented Apr. 15

Neil Shaw Muir and William 'C'hll'lel mm",- -Farnborongh, and John Harold Whitaker.

Ughtcliife, England ap ucl u n January 11, 1940, sci-m re. 14,330

Great Britain January 1 i 1 Claim- This invention relates to pumping apparatus more especially for operation by a source of power vention is particularly but not exclusively applicable to apparatus for delivering fuel from a main f fu'el reservoir either directly or through reducing or other valves or through a gravity tank or other subsidiary reservoir to the caburettor or carburettors or other fuel feeding apparatus of one or .more internal combustion engines.

For example in aircraft the main fuel reservoirs may be situated at a distance from the engine, for example in the wings, and if the pump is driven directly by the engine the supply .of fuel may fail due to the atmospheric pressure being insufllcient to force the fuel to it or-the pump being incapable of sucking the fuel to the necessary height, par- .ticularly when starting up.

apparatus comprises a delivery pump, a fluid motor for driving the delivery pump, and an operatingpump for delivering fluid under pressure to drive ,the'fluid motor, characterised in that the fluid delivered by the operating pump to the motor is derived from the supply of fluid to be pumped.

Thus in one form fluid motor coupled to the delivery pump to drive it, an operating pump and conduits for tapping .oil a portion of the fluid delivered by the delivery The delivery pump and fluid motor may have a common delivery outlet and their rotors may be coaxial and directly coupled or constituted by a single combined freely mounted rotor.

Preferably the motor is. constituted 'by an inward flow turbine which possesses a stable speed characteristic. Thus, for example, one face of a combined rotor may have its outer portion formed with vanes of an inward flow turbine and its inner portion formed with vanes of a centrifugal delivery pump and be adapted to cooperate with a single outlet at an intermediate radius formed in a casing common to the turbine and pump. The centrifugal pump is preferably situated so that the liquid enters it downwardly.

The invention may be carried into effect in various ways but one specific arrangement will be described by way of example with reference to the accompanying drawing. in which of the invention apparatus "for pumping liquid includes a delivery pump, a

(Cl. tilt- 5) Figure 1 is a diagram of a fuel supply system for an aircraft, and I Figure'2 is a diagrammatic sectional view of the combined delivery pump and fluid motor on a larger scale. Y

The purpose of the pumping system is to deliver fuel suchas petrol to an internal combustion engine A from a fuel tank B which may be situated at a distance from it. To this end there is mounted in the bottom of the fuel tank or adjacent thereto a combined fluid motor and delivery pump. As shown in greater detail in Figure 2 this comprises a common casing C within which is mounted a combined rotor D. The outer portion of the rotor is formed to constitute vanes E of an inward flow turbine whilst the inner portion has on its upper face vanes Fat a centrifugal delivery pump. The rotor is mounted in bearings C which are indicated diagrammatically as consisting of ball bearings but may be any preferred form of bearing suited to the prevailing conditions as to operation and lubrication or lack of lubrication. The inlet to the centrifugal 'pump takes place in a downward direction at (l whilst the inlet C to the turbine is at-the outer periphery of the casing and is provided with gu de vanes C. A common outlet 0 serves both the turbine and the motor at an intermediate radius.

The arrangement of the pipe lines is shown in Figure l. in operation the delivery pump F 'delivers li uid through a delivery pipe G to the carburettor A of theinternal combustion engine A. At a point in the pipe G near the engine'the liquid passes into a small reservoir H from which a portion of it can be drawn off through a pipe J to an or erating pump K driven directly by the main engine or an auxiliary engine. The operatlng pump K delivers such fuel at an increased pressure through a pipe L to the inlet C of the 40 turbine so as to drive it and operate the delivery pump F. Thus it will be seen that the arrangement relies upon utilising a small portion of a fluid at a relatively high pressure to deliver a larger portion of 45 the same fluid at a lower pressure.

Preferably the delivery pipe G from the-delivery pump includes a handoperated priming pump M for the initial flll'ing of the main pump and pipe system and carburettor or other fuel feeding ap- 50 paratus on the engine. A fuel flow meter N may also be provided together with a pressure reducing valve P adapted to give any required fuel pressure at the carburettor or the like. Alternatively the pressure regulating valve on the operating pump to K may be controlled by the pressure in the main delivery pipe line and arranged to maintain a predetermined pressure at the carburettor by varying the pressure of the supply to the turbine.

Preferably a light spring-loaded valve Q is provided in the inlet to the turbine to prevent emptying the fuel from the pipe line L when pumping from the operating pump K ceases. The pipe G may also be provided. with a self-sealing valve if desired.

It will be appreciated that the vinvention provides an arrangement which automatically ceases to deliver fuel in the event of failure of either of the pipes leading to the fuel tank. Thus if the delivery pipe L of the operating pump K is fractured the liquid delivered by the operating pump K will not reach the turbine whilst if the delivery pipe G of the delivery pump F is fractured the supply of fuel to ,the operating pump K will cease and accordingly in either case the turbine will stop and all delivery of fuel will cease. The system a oids the use of suction and relies on a positive pressure atall parts of the fluid path,

and the centrifugal delivery pump functions as a separator tending to force any bubbles of air in the liquid towards the axis whence they can escape back into the tank.

What we claim as our invention and desire to secure by Letters Patent is: A

A pumping apparatus especially adapted for use with an internal combustion engine, and a tank for liquid comprising a centrifugal delivery pump and inward flow turbine arranged vadjacent the tank to deliver liquid from it to the engine and having a single combined rotor mounted to rotate freely whereof the outer portion of one face is formed with vanes to constitute the rotor of the turbine whilst the inner portion of the same face is formed with vanes to constitute the rotor of the delivery pump, the two sets of vanes coopcrating with a common delivery outlet at an intermediate radius. I

JOHN HAROLD WHITAKER.

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