US2952214A

US2952214A - Fuel pump

Info

Publication number: US2952214A
Application number: US636442A
Authority: US
Inventors: Harold E Adams
Original assignee: Nash Engineering Co
Current assignee: Nash Engineering Co
Priority date: 1957-01-25
Filing date: 1957-01-25
Publication date: 1960-09-13
Anticipated expiration: 1977-09-13

Description

Sept. 13, 1960 Filed Jan. 25, 1957 H. E. ADAMS FUEL PUMP 7 Sheets-Sheet 1 INVENTOR. Harold 15. Adams ATTORNEY-5 Sept. 13, 1960, H. E. ADAMS 2,952,214

FUEL; PUMP Filed Jan. 25, 1957 7 Sheets-Sheet 2 4 INVENTOR.

Ham/a7 E. Adams A TTOff/YE Y5 Sept. 13, 1960 Filed Jan. 25, 1957 E. ADAMS 2,952,214

FUEL PUMP 7 Sheets-Sheet 3 I grime/rm Harold'i/ldams.

Sept. 13, 1960 I H] E. ADAMS I 2,952,214

FUEL PUMP Filed Jan. 25, 1957 7 Sheets-Sheet 4 a v vue/rvbo n Haro/d 15A dam:

Sept. 13, 1960 I H. E. ADAMS FUEL PUMP Filed Jan. 25, 1957 7 Sheets-Sheet 6 Fig? Mme/War Harv/d EA dams ATTORNEYS Sept. 13, 1960 I H. E. ADAMS 2,952,214

FUEL PUMP Filed Jan. 25, 1957 7 Sheets-Sheet 7 Myer/for Ham/d E. Adams A TTORNFYS United States Patent FUEL PUMP Harold E. Adams, South Norwalk, Conn., assignor to Nash Engineering Company, South Norwalk, Conn., a corporation of Connecticut Filed Jan. 25, 1957, Ser. No. 636,442. 16 Claims. (Cl. 103-113) The pump of this invention is constructed to handle multiple component liquid fuels near their boiling points through tortuous suction lines. The diflicult nature of this operation is well known in the aircraft industry where fuel has to be transported within the airplane from fuel tanks located in the fuselage or in the wing, out to the main engine, which may be located at the outermost point of the wing or above or'below the wing. The piping between the tank and the engine has to follow the airplane configuration. These piping conditions are usually so bad in relation to the gas and vapor forming characteristics of the fuel that it is impractical to 'draw the fuel through this piping by means of an ordinary pump located at the engine.

It is general practice to place an additional p mp within the fuel tank to transport the fuel through the piping to the inlet of the main engine pump under a sufiicient pressure to overcome the pressure drop of the piping and meet the inlet pressure requirement of the main engine pump. Such pumps in the art are known as tank mounted booster pumps. 7

By the use of novel features of my pump, I can place it at the engine and pump the fuel through the intervening suction lines without the continuous aid-of the additional tank mounted booster pump.

The principal pumping difiiculty is caused by the friction drop existing in the piping when fuel is flowing, which results in the evolution of gases and vapors in the pipe from the fuel. High spots or pockets formed by the piping allow the evolved gases and vapors to accumulate therein. In some cases these bubbles grow and gradually reduce the available pipe area for the flow of the liquid fuel, even to the point of causing the stoppage of all pump inlet passageway with gas or vapor, both of which will starve the pump and engine resulting in fuel flow stoppage. Such characteristics are often known inthe art as vapor lock.

Because of the aforementioned difiiculty, it is common practice to supply a sufiicient pressure or static head at the inlet to the piping system so that the pressure throughout the piping system is enough to prevent the coming out of solution of gases or vapors due to the friction drop, with a margin of pressure left to pressurize the inlet to the main engine pump. This pressure head is usually provided, on land installations, by raising the tank to a static height suflicient to give the desired pressure. This, of course, cannot be accomplished in an airplane, so the desired pressurizing of the piping system is usually obtained by means of a tank mounted fuel booster pump. In some cases, tanks are pressurized by air or gas erally practised on aircraft because of the objectional weight penalty, etc.

In the case of airplanes dependent upon the pressurization of the fuel lines by tank mounted booster pumps, the airplane is vulnerable to the failure of the tank mounted booster pumps or any malfunction of this fuel fiow, or the partial filling of the.

to obtain this result, but this is not gen- I pump or its driving motor. Such failure usually results in the necessity of the airplane to come down to a much lower altitude to obtain a higher ambient absolute pressure, such that the fuel will not evolve gases or vapors. The main engine pump, or its booster pump, located at the engine, generally has very limited performance, even at the reduced altitude and speed, without the assistance of the tank mounted booster pump. This, of course, is not a desirable situation and it is the purpose of my pump to enable the airplane to continue normal flight at a high altitude, in the event of the failure of the tank mounted booster pump.

When the fuel is being pumped from the fuel tank through the fuel piping system under conditions of reduced pressure approac 'ng saturated gas conditions, or where the absolute pressure in the pipe line nears the vapor pressure of the fuel, there occurs the evolution from the fuel of the saturated air and gas, plus the vaporization of some of the lighter, more volatile constituents of the fuel. This evolved gas and vapor will accumulate in the high points or pockets in the fuel line. These gas pockets grow, to the point where it breaks the syphon effect of the piping and imposes an additional lift on the pump. It may be carried over in gulps if the flow velocity is great enough, or, under lowvelocity, the gas-vapor pocket may grow until it reaches the pump inlet. At this point, the pump only has the gas-vapor to work on and there results a serious interruption in the delivery of fuel to the engine.

My novel application to an airplane fuel system is shown herein as typical of the type of work for which my pump is well'suited but it can be used on many other difficult two-phase pumping problems and I do not intend that it be limited merely to the application shown. A high point or gas collecting pocket may be deliberately added to the suction line above and ahead of the pump inlet to collect evolved gases for the gas removal element to handle. This pocket may also be deliberately connected to a large chamber to serve as a surge and separating chamber in the case of the two-phase liquidgas flows involving severe slugging and other turbulent conditions which would be difiicult to pump with either a positive or a centrifugal type pump.

In my novel pump, dependently and continuously withdraw the gas and vapor from the pocket or pockets in the pipe line as they form. By thus continuously withdrawing this gas and vapor, the suction line ahead ofthe inlet of the pump is kept relatively free of large intermittent bubbles and gulps of air, which would otherwise interrupt the pumping action. This additional vapor and gas removal provides a denser head of liquid at the entrance of the pump, which, of course, giva a better inlet condition for the pump itself and thus further aids in the efiicient handling of the fuel.

This novel auxiliary vapor-gas removal feature, which is built into my pump, is in addition to several other features which will subsequently be described and which are included to give a self-contained novel pumping unit for problems of this kind.

Other features and advantages will hereinafter appear.

In the drawings which form part of the specification:

Fig. 1 is an elevation of an airplane showing the invention applied thereto;

Fig. 2 is a view on a larger scale showing part of the piping system of Fig. 1;

Fig. 3 is a view similar to- Fig. 2, showing how the parts function when my invention is employed;

Fig. 4 is a vertical longitudinal section taken on the line 4-4, of Fig. 6 looking in the direction of the arrows;

Fig. 5 is a vertical longitudinal view in section taken on the line 55 of Fig.- 6;

I provide built-in means to in- I Fig. 6 is a vertical section taken on the line 6-6 of Fig. 4 looking in the direction of the arrows;

Fig. 7 is a vertical section taken on the line 7--7 of Fig. 4 looking in the direction of the arrows; and

Fig. 8 is a vertical section taken on the line 8-,8 of Fig. 4 looking in the direction of the arrows.

In the specification similar reference characters designate similar parts in each of the various views.

A typical arrangement of fuel piping on a modern airplane is shown in Fig. 1. In this arrangement, the fuel is carried in one of the fuel tanks 1 from which it is pumped by the booster pump 2, through the fuel lines 3 and 3a, which lead across the wing structure to the engine pylon mounting. Then the fuel piping leads to the lower end of this mounting to the engine driven booster pumps 7 of my invention only one of which is shown.

It will be noted from this view that there is a high spot in the pipe line at 4, at which a bubble may form. There is also indicated a fitting '5 in the line, which is typical of a valve, heat exchanger, strainer, etc., which will produce a local pressure drop point immediately beyond it and where additional bubble formation is likely to occur. An auxiliary suction pipe 6 is run from the pump 7 of the invention with connections to each of these gas forming locations at 10 and 11. The booster pump delivers through its discharge line 8 into the main engine pump shown at 9 and fuel is delivered from there into the engine by the main engine pump.

A larger cross section illustrating typical flow conditions in the fuel piping system at the critical areas 4 and is shown in Fig. 2. It will be noted that the gas bubble in Fig. 2 has grown to such an extent as to prettymuch restrict the flow of fuel, as well as to break the syphon elfect of the down leg of the pipe. There is only a small channel of fuel running along the lower part of the pipe. Under these conditions, the inlet to the pump is open to the gas, which would in itself result in failure of a normal centrifugal pump. Even a positive displacement pump cannot reach the fuel until it removes this air. All advantage of a possible static head of fuel assisting the pump on the suction side is also lost because of the channeling of the liquid in the pipe line instead of the pipe line being filled solid with liquid.

Fig. 3 shows the improvement in the flow conditions when my invention is applied in the manner prescribed. Local restrictions are placed at It} and 11 to match the capacity of line 6. It will be noted that the pipe line 3 is kept full of fuel, thus preventing gas and vapors from being drawn into the pump inlet and also providing a static head of fuel above the pump inlet for better pumping conditions.

The pump itself is shown in Figs. 4, 5, 6, 7 and 8. The main centrifugal pump impeller 15 is in accordance with the teachings of my Patent 2,461,865. This impeller, by its design, is capable of handling a liquid with a high percentage of gas and vapor present with the liquid. The impeller passageways 17a between impeller blades 17 are so proportioned as to centrifugally separate the gas and vapor from the liquid within the bladed portion of the impeller. The gas-free liquid is discharged against pressure through the volute 18 and main discharge of the pump 19, while the separated gas and uncondensed vapor are directed towards an annular collecting groove 20 near to and surrounding the main inlet 16 to the impeller. From this collecting groove 20 one of the built-in liquid ring compressors 24 continuously withdraws the separated gas. It may be also noted that my said copending application, Serial 256,580, is designed for operation as an engine driven booster pump. Improvements of the present invention over this co-pending application will be readily observed from the following description.

In the present invention, I provide what amounts to four pumps with one unitary impeller 15. The main suction of the pump is located at 16. The fuel entering through this suction opening is picked up by the blades 17 of the vapor-gas separating portion of the impeller. The fuel and vapor or gas mixture picked up by these blades 17 are separated by centrifugal action within the casing as the blades rotate in a manner similar to that described in my Patent 2,461,865. Fig. 8 shows a cross section through these impeller blades 17. The separated gas-free liquid is delivered through the volute passageway 18 and the final discharge 19, while the separated gas and non-condensible vapors are directed to the collecting groove 20 near the entrance of the casing. At point 21 (Fig. 4) these gases and vapors collected in the groove 20 are withdrawn through passageway 22 (Figs. 4 and 6) to the inlet port 24a of one suction chamber 24 of a liquid ring compressor 32 provided on the opposite side of the impeller 15, having blades 23 and the lobe casings 24 and 30. The gases and vapors are compressed by the liquid ring compressor 32 and delivered through discharge ports 24b to the interior annular space 25 (Fig. 7). Fig. 4 is a cross section showing the above passageways. From here, the mixture of condensed vapors, gas and liquid are picked up by the intermediate blades 26 of the second stage centrifugal pump formed by these blades 26 and the two

side walls

27 and 27a of the main impeller 15. The mixture discharged by the liquid ring compressor 32 to chamber 25 is thus continuously picked up and centrifugally discharged through the blades passageways 28 to the volute chamber 18 into which the main liquid flow has been discharged by the previous mentioned set of blades 17. Fig. 7 shows a cross section through the blades 26 of the second stage impeller.

In the process of suction and compression in the liquid ring compressor 32 the vapors are condensed and most of the free gas is absorbed at the higher discharge pressure at 25 from the liquid ring compressor. They are further pressurized by the action of the intermediate centrifugal 26 and the liquid delivered to the same terminal pressure as that developed by the main impeller blades 17. The introduction of the intermediate blades 26 of the present invention allows the liquid ri-ng compressor 32 to operate over a normal compression range rather than having to operate over abnormally high compression ranges, as is the case with my co-pending application, Serial 256,580, where it has to deliver the compressed mixture either against that developed by the main impeller or against the reduced regulated pressure from the main impeller.

Another feature distinguishing this invention, which is shown in Fig. 5, is the provision of a separate lobe 30 which is used to maintain a suction through connection 31 and pipe 6 to the vapor-forming pockets 10 and 11 in the suction line 3, as previously outlined. Vapor and gas are withdrawn from these pockets through connection 31 into the port 30a of the liquid ring compressor lobe section 30. The suction and compressive action in this lobe 30 are entirely independent of the suction and compressive action of the other lobe 24 used for scavenging the main impeller 15. The vapors and gas removed from the pipe line pockets are compressed in the liquid ring compressor 30 and discharged through ports 30b into the same annular chamber 25 that receives the discharge from the impeller scavenging lobe 24. The discharges of the two liquid ring compressor lobe sections 24 and 30 are therefore combined at this point and both are pumped to the higher volute pressure 18 by the common second stage impeller blades 26.

It will be noted that the gas-vapor phase is handled in two stages. The first stage is a liquid ring compressor using the pipe line liquid as the liquid piston. This liquid is continuously replenished by liquid drawn in with the gas and vapor. In the liquid ring pump, the mixture is compressed to an intermediate stage pressure and in so doing, the vapors are condensed and the gases are reabsorbed back in the liquid so that little, if any, free gas or vapor is present in the discharge from the liquid detect;

ring compressor. It is practically all liquid. After this work of compression has been completed and to stabilize this liquid further, it is passed through the second stage centrifugal pump. Here it is brought up to the final pump discharge pressure and discharged into the common and final liquid discharge.

I The liquid ring compressors are only required to have the compression ratio necessary to condense and absorb the vapors and gases removed from both the collecting

pockets

4 and 5 and the main impeller entrance groove 20. The second stage centrifugal impeller is furnished to deliver this liquid from the discharge of the liquid ring pump to the final discharge pressure of the main centrifugal pump.

From the above description it will be understood that I provide four pump portions A, B, C and D with one unitary impeller 15. Pump portion A has the property of centrifugally separating the entrained gas and liquid arriving atits inlet, and serves to discharge the liquid separately through a discharge connection, and to reject the separated air and vapor to a separate port, where it will be handled by pump portion B.

The parts which make up pump portion A include the vanes 17, Figs. 5 and 8 in cooperation with the enveloping casing 40 and the volute -18 formed therein. Vanes 17 are integral with the central driving shroud 27, which is driven by the main shaft 41, this shaft being driven by a motor, not shown, through the coupling member 42. The casing 40 also forms the main inlet to the pump 16, the air vapor collecting groove 20 with its connection 21 for removal of the separated air and vapor and the final discharge connection 19.

It will thus be seen that the function of pump portion A is to pump the liquid from the system 3 to which it is connected, pressurizing it and delivering it to higher pressure'through the discharge connection 19. Pump portions B and C are included in casing 32. This casing surrounds a rotor formed by blades 23, attached. to an extension 27a, Fig. 4, and driven by the central driving member 27 through blades 26. This rotor also has an external shroud member 45 enclosing the ends of the blades 23. These pump portions B and C are of double-lobed liquid ring compressor type. Pump portion B of this double lobed liquid ring pump is defined by one lobe 24,- as shown in Figs. 4 and 6, together with central inlet port 24a and discharge port 24b.

The function of pump portion B is to continuously remove the separated gas and vapor directed to the an nular groove 20 and the take-up point 2-1, removing this mixture from the pump portion A through conduit 22 and inlet port 24a. A further function of pump portion B is to compress the gas and vapors so removed. In this process it condenses the said vapors and causes the gas to be absorbed by the liquid of the liquid ring portion in lobe 24, delivering the excess liquid upon final com pression through the discharge port 241:, from which port it is picked up by pump portion D to which I shall refer later.

Pump portion C is defined by the opposite lobe 30, Figs. 5 and 6, of the liquid ring pump, and is provided with inlet port 30a and discharge port 30b. The function of this pump portion C is to remove gas and vapor from high collection points formed in the suction. line piping attached to the main pump at 16, this suction being maintained through connection 31 and pipe 6, the purpose being to continuously remove gas and vapor collecting in the high points of the suction line, withdrawing them into the liquid ring pump through inlet port 30a, and compressing this mixture and discharging the condensed mixture through the discharge port 30b to the inlet 25 of the aforementioned pump portion D.

Pump portion D is a centrifugal liquid pump formed by the intervening blades 26 extending between the drive shroud member 27 and the opposite shroud member 27a,

and is shown incross section in Fig'. 71 The purpose of this pump is to take the discharge from pump portions B and C, through suction connection 25, and centrifugally pressurizing this mixture and delivering it to the volute 18 at the higher pressure maintained in volute 18 by pump portion A, thus removing this work of delivering to the higher pressure from the compressor pump portions B and C, so that they can operate in their normal compression range. The output from pump portion D' is thus combined with the outlet from pump portion A in the main collecting volute 18, from which it is discharged through the final discharge connection 19.

Briefly stated, I provide a vapor separating centrifugal pump or booster equipped with an individual vapor re moval pump portion, which constantly removes separated vapors and gas from the interior of the main pumping element and these elements are also combined with a separate and independent vapor removal element to continuously remove the evolved gases as they collect at remote high points in the suction line ahead of the main pump, and the vapor-gas removal pump portions compress and condense these vapors and absorb the gases, discharging both with other liquid to the common discharge of a second stage centrifugal, which then discharges this combined mixture with the liquid discharge of the main centrifugal impeller element.

The four combined pumping elements are thus designed to work together for the efficient delivery of pressurized, stabilized liquid from a suction line flowing with this liquid in a separated two-phase and unstable con- 'dition.

The liquid ring compressor pump portions B and C are supplied with liquid for the sealing ring of these compressors by the normal amount of entrained liquid coming to them with the gas and vapors removed from the impeller collecting ring 20 and the vapor removal line 6, respectively. There are times, however, when the proportion of gas-vapor in the suction line 3 might be such as to preclude the possibility of liquid being carried over to the compressor pump portions B and C with the removed gas and vapor, in which event the liquid ring compressor pump portions B and C might exhaust the supply of sealing liquid therein and thereafter become inoperative because of the loss of the liquid ring and subsequent gas or vapor binding of the compressor.

To insure the continued maintenance of the liquid ring in this compressor, I provide means for supplying liquid from the pressurized portion of the volute 18 to the lobes of the compressor pump portions B and C. In addition to the liquid in the volute there will be the liquid available, in the pipe line 8 or, should a special situation develop, where additional seal liquid might be required to be on tap, I provide an additional auxiliary storage chamber connected to the volute or the seal supply chamber 50 for this purpose. A

The sealing liquid auxiliary supply chamber 50 is shown in Figs. 5 and 6 and is an annular chamber formed by the outer casing 53 and the inner casing 54 of the liquid ring compressor, as shown in Fig. 4.

Seal liquid supply for chamber 50 is fed from the volute 18 through feed hole 51.

The liquid seal feed hole 55 for compressor B is shown in FlgS. 4 and 6 and the liquid seal feed hole 52 for the pump portion C is shown on Figs. 5 and 6. noted that these seal feed holes are located in the lobe at the point of highest pressure built up Within the lobe casing, that is, at a point near the final discharge from the lobe. These holes are placed so as to enter the casing at the highest pressure point of the compressor casing This pressure, however, is less than the pressure in thevolute by the difference between the pressure built up by the intermediate second stage pump portion D. Under these circumstances, a small amount of liquid only wouldbe supplied to the compressor lobes; as would occur with the pressure differences noted. If,

however, the liquid ring pump should start to run out of seal, with resulting lessened pressure within the respective lobe casings, the reduction in pressure at this point would result in a greater pressure difference across the seal feed holes 52 and 55, with resultant increase in delivery of liquid to the liquid ring casing to restore the liquid ring to its full depth.

In the manner above shown, I provide for a continuous supply of liquid for the liquid ring compressor, even though the inlet connections to each respective compressor handle gas and vapor alone. In this way, the operation of the liquid ring compressor is maintained under such dry inlet conditions to keep up the efficient handling of vapor and gas under most critical main inlet conditions.

I have described what I believe to be the best embodiments of my invention. I do not wish, however, to be confined to the embodiments shown, but what I desire to cover by Letters Patent is set forth in the appended claims.

I claim:

1. In combination, a first pump portion having a liquid discharge connection and a separate gas and vapor discharge port, said first pump portion including a first rotary element having vanes and a casing having a volute formed therein for cooperating with said vanes and leading to said discharge connection to centrifugally separate the liquid from the gas and vapor entrained therein, to pressurize said liquid and to deliver the liquid to said liquid discharge connection and the gas and air to said separate gas and vapor discharge port, second and third pump portions constituting a double lobe liquid ring compressor including wall means defining a substantially elliptical chamber and a second rotary element rotatable therein, said second pump portion having a discharge port and an inlet connected to said vapor discharge port to continuously remove the said separated gas and vapor from said separate gas and vapor port of said first pump portion, and to compress the gas and vapor so removed, and to cause the said gas and vapor to be absorbed by the liquid of the liquid ring portion of said compressor and to deliver the said liquid to its said discharge port, said third pump portion having a separate discharge port and an inlet extending to the exterior of said third pump portion for connection to an external suction line to continuously remove gas and vapor from said suction line and to compress the said gas and vapor so removed, and to cause the said gas and vapors to be absorbed by the liquid of the liquid ring portion of said compressor, and deliver the said liquid to its said separate discharge port, and a fourth pump portion, said fourth pump portion including a third rotary element arranged to take the discharge from the discharge ports of said second and third pump portions and to centrifugally pressurize this mixture and deliver it at the higher pressure into the discharge connection of said first pump portion.

2. The combination of claim 1, in which each of the rotating elements is comprised in a unitary impeller structure.

3. The combination of claim 1, in which each of the rotary elements is comprised in a unitary impeller, said impeller comprising a central driving shroud, said first pump portion comprising vanes integral with said driving shroud and extending from one side of said shroud, said second and third pump portions comprising blades extending from the other side of said shroud, and said fourth pump portion comprising blades intervening between said last-mentioned blades and said shroud.

4. In a fuel system including a fuel tank, an engine fuel pump removed from said tank, fuel piping from said tank to said fuel pump, said piping having a pocket in which evolved gas and vapors from the fuel accumulate, the improvement comprising a booster pump installed in said fuel piping, said booster pump comprising a first pump having its inlet connected to said fuel piping and 8 having -a 1iquid discharge connection and a separate gas and vapor discharge port, said first pump portion including a first rotary element having vanes and a casing having a volute formed therein for cooperating with said vanes and leading to said discharge connections to centrifugally separate the liquid from the gas and vapor entrained therein, to pressurize said liquid and to deliver the liquid to said liquid discharge connection and the gas and air to said separate gas and vapor discharge port, second and third pump portions constituting a double lobe liquid ring compressor, including wall means defining a substantially elliptical chamber and a second ro tary element rotatable therein, said second pump portion having a discharge port and an inlet connected to said vapor discharge port to continuously remove the said separated gas and vapor from said separate gas and vapor port of said first pump, and to compress the gas and vapor so removed, and to cause the said gas and vapor to be absorbed by the liquid of said compressor and to deliver the said liquid to its said discharge port, said third pump portion having a separate discharge port and an inlet extending to said piping in the location of said pocket to continuously remove gas and vapor from said fuel piping and to compress the said gas and vapor so removed, and to cause the said gas and vapors to be absorbed by the liquid of the liquid ring portion of said compressor, and deliver the said liquid to its said separate discharge port, and a fourth pump portion, said fourth pump portion including a third rotary element arranged to take the discharge from the discharge ports of said second and third pump portions and to centrifugally pressurize this mixture and deliver it at the higher pressure into the discharge connection of the said first pump portion.

5. The combination of claim 4, in which each of said first, said second, and said third and fourth pump portions include a rotating element formed into a unitary impeller.

6. The combination of claim 5, wherein said impeller comprises a central driving shroud, said first pump portion comprising vanes integral with said driving shroud and extending from one side of said shroud, said second and third pump portions comprise blades extending from the other side of said shroud, and said fourth pump portion comprises blades intervening between said lastmentioued blades and said shroud. I

7. The subject matter of claim 1, in combination with means for supplying liquid to the lobes of the second and third pump portions.

8. The subject matter of claim 7, in which the said means comprises means constituting an auxiliary supply chamber and connections from said chamber to said second and third pump portions.

9. A pump comprising a rotatable main lmpeller, casing wall means defining a central fiuid inlet and a peripheral volute discharge for said impeller, a rotatable liquid ring compressor rotor, said casing wall means including a centrally located rotor inlet and rotor discharge and a substantially elliptical ring in which said rotor is rotatable and including a connection between a location in the vicinity of said fluid inlet and the central portion of said rotor to deliver air and vapor from said impeller to said rotor for compression and condensation of liquid thereby, and an intermediate impeller having a central inlet connecting said rotor discharge and positioned to discharge peripherally into said volute discharge.

10. A pump according to claim 9, wherein said casing Wall means includes portions at the center of said rotor defining two inlets one of which is connected to receive air and vapor from a location exteriorly of said 11. A pump comprising a casing having a central inlet opening and an annular discharge passage, a continuously rotated main shaft, a triple function impeller rotor affixed to said ,sh-aft including impeller means positioned adjacent said inlet and arranged to discharge fluid radially 9 to said discharge portion, said casing including a substantially elliptical chamber and conduit means connecting a portion of said casing in the vicinity of said inlet with the central portion of said elliptical chamber, said impeller means including a liquid compressor rotor portion afiixed to said shaft for rotation in said elliptical chamber, and an intermediate impeller portion aflixed to said shaft and having a central inlet in communication with the central portion of said elliptical chamber and arranged to discharge radially to said discharge portion.

.12. A pump according to claim 11. including conduit means in said casing connecting the central portion of said chamber to the exterior of said casing for -11 nection to an external fluid line.

13. A pump according to claim 11 wherein said impeller means is of unitary construction.

14. In a pump system comprising a fuel reservoir, and a suction line extending above said reservoir and having a suction therein, said suction line including a portion in which gas and vapors evolved from the fuel tend to accumulate, the improvement comprising a pump connected to said suction line, the pump including a rotatable main impeller, casing walls defining a centnal fluid inlet connected to said suction line and a peripheral volute discharge, wall means defining a substantially elliptical chamher, a rotatable liquid ring compressor rotor arranged for rotation within said chamber and air and vapor discharge port defined in said casing adjacent said inlet, means connecting said port with the central portion of said elliptical chamber to deliver air and vapor from said impeller to said rotor for compression and condensation of liquid thereby, means connecting the gas and vapor accumulation portion of said suction line to the central portions of said elliptical chamber, and an intermediate impeller having a central inlet connecting said rotor discharge and positioned to discharge peripherally into said volute discharge.

15. In a fuel system including, a fuel tank, an engine fuel pump removed from said tank, fuel piping from said tank to said engine fuel pump, said piping having a pocket in which gas and vapors evolved from the fuel accumulate, the improvement comprising the addition of a booster pump located in the vicinity of said engine pump, said pump having a main inlet connected to said piping and a discharge connected to deliver fuel to said engine pump, said pump including a liquid compressor portion having a separate compressor portion inlet connected to the gas and vapor pocket of said piping to continuously remove gas and vapors from said piping and including rotating means to cause said gas and vapor to be absorbed by the liquid of said compressor portion.

16. In a fuel system according to claim 15, impeller means connected to said compressor portion, and arranged to continuously receive liquid therefrom and deliver it at increased pressure to the discharge of said booster pump.

References Cited in the file of this patent 1 UNITED STATES PATENTS 1,983,131 Hume Dec. 4, 1934 2,018,110 Auter Oct. 22, 1935 2,278,397 Scheibe et a1 Mar. 31, 1942 2,306,841 Adams Dec. 29 1942 2,500,227 Adams Mar. 14, 1950 2,500,228 Adams Mar. 14, 1950 2,581,828 Ad ams Jan. 8, 1952 2,737,897 Dewees Mar. 13, 1956 2,845,871 Compton Aug. 5, 1958 FOREIGN PATENTS 345,973 Great Britain Sept. 27, 1929 511,305 Great Britain Aug. 16, 1939 UNITED STATES PATENT OFFICE CERTIFICATION OF CORRECTION Patent No. 2,952,214 September 13 1960 Harold E. Adams rror appears in the above numbered pat- It is hereby certified'that e the said Letters Patent should read as ent requiring correction and that corrected below.

Column '7, line 75, after "pump" insert portion --=a Signed and sealed this 26th day of June 1961.

(SEAL) Attest:

ERNEST W. SWIDER Attesting Officer DAVID L. LADD Commissioner of Patents