US2301496A - Fuel pumping system - Google Patents

Description

Nov. 10, 1942. L. l. ALDRICH FUEL PUMPING SYSTEM Filed March 24, 1941 IN VENTOR.

' the pump directly to the intake thereof.

"Patented Nov. 10, 1942 OFFICE FUEL PUMPING SYSTEM Loyd I. Aldrich, Wyoming, Ill.

AlmllcationMarch 24, 1941, Serial-N0. 384,827

8 Claims.

My present invention relates to a fuel system for fuel or other liquid having a pump so designed as to eliminate noise.

One object of the invention is to provide a pump which is of comparatively simple construction and which has features of 'design which give the effect of an air chamber as used in connection with water pumps or the like to eliminate the noise resulting from unequal flow of liquid as the impellers of the pump successively pass the outlet of the pump. In this connection, i-t.may be mentioned that impeller type pumps, such as those embodying a pair of meshing gears, have heretofore been used extensively for the pumping of fuel oil'under pressure to a burner nozzle. Considerable noise hasbeen experienced in the operation of such pumps where a pressure relief valve acts as a by-pass to return fuel in excess of that required for operation of the burner nozzle usually from the outlet of Such noise is amplified particularly when the supply tank is nearly empty, due to being transmitted into the tank and the ends thereof acting as diaphragms responding to the periodic changes in fuel velocity as it flows to the pump.

Another object, therefore, of my present invention is to provide a pump wherein voids-in the fuel are generated by an arrangement which auxiliary intake being so located with respectto the main intake and the outlet of the pump that it upplies the fuel required and permits preferred and desirable embodiment of the invention in the accompanying drawing, in which:

Figure 1 is a semi-diagrammatic view showing my pumping system used in connection with an tip I! for spraying oil into the blast of air to operation of the pump in such fashion that the voids above referred to are generated.

With these and other objects in view, my invention consists in the construction, arrangement and'combination of the various parts of my device whereby the objects contemplated are attained, as hereinafter more fully setforth, point-' ed out in my claims and illustrated in the accompanying drawing. Although the invention is-sus- I ceptible of a variety of embodiments, it is unnecmunlcates.

produce a combustible mixture, and a by-pass and nozzle opening valve arrangement including a valve stem I3 and a valve plunger l4. The valve stem I3 is normally held seated against a seat 15 by a spring IS. The spring It may be adjusted by means of a rod H to the desired pressure of fuel oil discharged from the nozzle tip l2. v

A supply pipe I8 is connected with the nozzle valve NV for supplying oil through a strainer l9 to the valve seat It and to the interior of the piston l4. Such oil acts against the inner end of the piston II to first force it toward theright in Figure 1 against the tension of the spring l6, thereby opening the nozzle valve at l3-l5 and finally permitting by-pass of some of the fuel oil through ports l8 into an enlarged space IQ of the nozzle valve NV. The oil then flows through a pipe 20 to a return line 2|. The spring ll will balance the pressure of oil supplied from the pipe II to maintain a given pressure (somewhat lowerthan supplied by the pipe) of discharge from the nozzle tip l2. The excess oil is then returned or by-passed through l8, I9, 20 and 2! to the pump.

The pump itself is indicated generally at P and includes a casing 22 having a pair of impellers therein indicated at 23 and 24. The impellers are shown as of the meshing gear type, although they may be'of any suitable shape. The casing "has a main inlet 25 with which the return pipe 1| communicates, an outlet with which the pipe ll communicates and an auxiliary inlet 21 with which a fuel supply pipe 28 comnoted, are located, as usual, opposite each other standpoints. Accordingly, I have illustrated .a B5

and substantially in alignment with the meshing teeth of the impellers 23 and 24. The auxiliary inlet 21' constitutes my novel contribution to the art for producing a silently operating pump. The

The pipe 28 extends from a source of fuel supply, such as atank T. v V

The main inlet 25 and the outlet 26,'it will be auxiliary inlet 21 is located a distance spaced from the main inlet 25, which is greater than the distance between the, outer end of two adjacent teeth of the impeller 24. Accordingly, the auxiliary inlet 21 is at all times sealed by at least one impeller tooth from direct communication with the main inlet 25 and likewise from direct communication with the outlet 26.

My arrangement can be somewhat modified, for instance as shown in Figure 2, wherein a second auxiliary inlet 21* is provided for the impeller 23 and the fuel supply pipe 28 extends to both this auxiliary inlet and the auxiliary inlet 21. A more mechanically balanced arrangement is thus secured.

Practical operation In the operation of my piunping system, assuming that the capacity of the pump at the outlet 26 is fifteen gallons per hour g. p. h.) as indicated on the drawing, and that the nozzle tip l2 at the pressure set by the spring l6 discharges -a discharge nozzle connected with the outlet thereof, a pressure relief valve between said nozzle and said outlet, a return line from said pressure relief valve communicating with the main inlet of said pump, and an intake for supplying additional liquid fuel to said pump, said intake being connected with a source of liquid fuel and being located to discharge into the space occupied by one of the gears of said pump at a point spaced a distance from said main inlet which is greater than the distancebetween the outer ends of two one gallon per hour, then fourteen gallons per 23 will accordingly generate voids 29 between any pair of teeth not in communication with the :main inlet or the outlet 26. In a similar manner, the impeller 24 will generate a void as at between any pair of teeth not communicating with .the main inlet 25 and the auxiliary inlet 21, but each pocket between adjacent teeth between the auxiliary inlet 21 and the outlet 26 will be filled to capacity (eight gallons per hour). The additional gallon per hour is supplied by the supply line 28, which gallon is added to the seven received from the main inlet 25.

The voids 29 and 30 are generated by a vaporizing action which takes place because of the vacuum created and which has the effect of vaporizing the higher ends of the fuel oil. The voids 29 and 30 thus serve in the capacity of minute air chambers to absorb the shock of variations in rate of liquid flow caused by the alternate meshing and unmeshing of the teeth of the im pellers 23 and 24. As soon as the pockets between the gear teeth communicate with the outlet 26, however, the oil is then under pressure to elimi-. nate the voids and prevent them from interfering with the atomizing action at the nozzle tip I 2.

In Figure 2 a better mechanically balanced arrangement is illustrated, although I have found that operation of the arrangement shown in Figure 1 is satisfactory and less complicated of manufacture. My arrangement gives the effect of an air chamber in the outlet line from the pump which is satisfactory in connection with pumping water or the like, but in connection with oil is inoperable because the air is absorbed by the oil and finally eliminated, as well as interfering with atomization of the oil at the nozzle tip.

Some changes may be made in the construction and arrangement of theparts of my device without departing from the real spirit and purpose of my invention, and it is my intention to cover by my claims any modified forms of structure or use of mechanical equivalents which may be reasonably included within their scope without sacrificing any of the advantages thereof.

I claim as my invention:

1. In a fuel pumping system, a gear type pump,

adjacent gear teeth.

2. In a liquid pumping system, a pump casing, a pair of meshing impellers therein, a liquid discharge element connected with the outlet of said casing, a pressure relief valve between said element and said outlet, a return line from said pressure relief valve communicating with the main inlet of said casing, and an auxiliary inlet for supplying additional liquid to said pump, said auxiliary inlet being connected with a source of liquid supply andbeing located to discharge into the space in said casing occupied by at least one of said impellers at a point spaced from said inlet and outlet at greater distance than the distance between the outer ends of two adjacent impeller blades.

3. In a fuel pumping system, a casing having an inlet and an outlet, gear type impellers therein and meshing with each other, a discharge nozzle connected with said outlet, a return line from said nozzle to said inlet, and an auxiliary inlet for supplying additional fuel to said pump, said auxiliary inlet being connected with a source of fuel and being located to discharge into the space occupied by at least one of said gears at a point spaced a distance from said inlet and outlet greater than the distance between the outer ends of two adjacent gear teeth.

4. In a liquid pumping system, a pump, having an inlet and an outlet arranged opposite each other, a pair of intermeshing impellers in said casing, a discharge pipe connected with said out let, a pressure relief valve between said nozzle and said outlet, a retumline from said pressure relief valve communicating with said. inlet, and an intake for supplying additional liquid to said pump, said intake being connected with a source of liquid and being located to discharge into said casing at a point spaced a distance from said inlet which is greater than the distance between the outer ends of two adjacent impeller blades.

5. A noiseless pump for supplying fuel oil or the like to a discharge nozzle having a by-pass line comprising a casing, a pair of meshing impellers therein, said casing having an outlet and a main inlet oppositely arranged substantially in alignment with the meshing teeth of said impellers, said outlet being connected to said nozzle, said main inlet being connected with said by-pass line and said casing having an auxiliary inlet connected with a supply of fuel and located to communicate with one of said impellers at a point so circumferentially spaced from said outlet and from said main inlet as to be at all times separated by the impeller blades from direct hydraulic communication with said outlet and said main inlet.

6. A noiseless liquid pump to supply liquid to a discharge nozzle having a relief pressure actuated return line comprising a casing, a pair of meshing gears therein, said casing having an outlet and a main inlet oppositely arranged substantially in alignment with the meshing teeth of said gears, said outlet being connected with communicate with one of said gears at a point circumierentially spaced from said outlet and said'main inlet to be at all times out oi direct hydraulic communication therewith, with at least one tooth of a gear interposed between said auxiliary inlet and said main inlet and at least one tooth of said gear interposed between said auxiliary inlet and said outlet.

' 7. In a noiseless pump for liquid supplied to a nozzle or the like having a return line, a casing, an impeller therein, said casing having an outlet and a main inlet arranged respectively to supply liquid to said nozzle and receive less liquid from said return line and an auxiliary inlet to said casing connected with a supply of liquid and point intermediate the outlet and inlet of said 8. In a noiseless pump for liquid supplied to a nozzle having a relief pressure actuated return line, a casing, a pair of meshing gears, said casing having an outlet and a main inlet oppositely arranged substantially in alignment with the meshing teeth of said gears, said outlet being connected to said nozzle, said main inlet being connected with said return line, and an auxiliary inlet to said casing connected with a supply of liquid and located to communicate with at least one of said gears at a point circumferentially spaced from said outlet and said main inlet.

LOYD I. ALDRICH.

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