US1830923A - Pumping system - Google Patents

Description

Nov. 10, 1931. BRADFORD 1,830,923

PUMPING SYSTEM Original Filed May 14, 1926 Patented Nov. 10, 1931 mm srA Es PATENT OFFICE FREDERICK E. BBADI'ORD, OI CHICAGO, ILLINOIS, ASSIGNOR '10 AUTOMATIC P311153 comm, OF CHICAGO, ILLINOIS, A OORPOBAT'ION OF ILLIN'OIS,

' ammo stem Application fled Kay 1;, 1m, Serial No. 109,087. Renewed November 19, 1887.

in the present invention are disclosed in the Patents 1,314,875 of eptember 2, 1919 1,377,256 of Mav 10, 1921, and 1,419,273 of June 13, 1922, all of which were granted to H. E. La Bour of Chicago, Illinois.

Such systems, however, have certain defacts which are overcome by the present invention. Obviously, if there is not enough liquid in the priming tank, a system of this kind will not start to operate. Also if during pumping a, suflicient uantit of the liquid becomes replaced by t e co ection of air or'any other gases in the priming tank, the system will also become air bound. That is to say, enough gas will collect in the priming tank to lower the liquid level below the pump intake to sto its operation. This is due to the fact t at centrifugal pumps cannot suck air.

It is so nearly impossible-to keepair and other gases from entering the priming tank that it is impractical to attempt to do this.

Gases in solution may become disentrained when coming into the region of reduced pressure in the tank, or they may also be drawn up from the source with the liquid as bubbles. The quantity of air or gas 1n the prim-' air into the surrounding. atmosphere while the liquid is fed from a point somewhat below the top of the separating tank to the tion provides a primary separating distributing system. This invention contemplates a novel and simplified vent for such separating tanks.

Another part of the present invention pro- I vides' for a speciallyl arranged inlet to the primin tank from t mizes e air space between the lift pipe inlet and the top of the riming tank.

Still another form oi tank having an automatically controlled -pass pipe between it and the priming tank, for removing'air from the primingtank during pumping and which also performs the function of the vacuum break in the Patent No. 1,417,273 above'cited.

In order that the invention ma be under- 1 stood by. those skilled in the rtment art,*it will hereinafter be disclose as embodied in a specific form which will be described in detail. Many other forms may be derived from the following disclosure and other uses e lift pipe which mini-.

the present inven-' may be. found to which this inventionmay lend itself.

In the accompanying sheet of drawing matter;

- Figure 1 is an elevation of the'meohanism m 'w 1ch the present invention is embodied,

the:1 most important parts being in section; an v Figure 2 is a similar view of a modified arran ment of a similar mechanism.

In igure 1, 5 indicates a centrifugalor valvelessgmmp having a power shaft 6 ada ted to be riven b any suitable means which ma be controlle automatically or manually an which form no part of the resent invention. The pump 5 has an inta e 7 and an outlet pipe 8. The intake connects with a priming tank 9 and the outlet communicates with a store e and separating tank 10. A suction or li assembly. It will be apparent from the drawing that a minimum of air space exists pipe 11 is brought into the A priming tank 9 as close to the top as possible,

and also to be at as low a level as possible 9 from the main separating tank 10. The vent between the top of the tank and the inlet pipe. The end of the tank is then inserted and welded into place, after which the pipe 11 is welded at 28. The pipe 11 is then connected with a well, as at 13, and is provided with a satisfactory screen 14 for keeping solid material out of the system.

.The storage tank is provided with an outlet 15 which may lead to the distributing system. Any desired type of distributing system ma be used with this suppl system. The out et '15 is located somewhat low the top of the tank in order that air or other gases may collect at the top to escape through a vent 16. This vent comprises a pipe which may lead back to the well or to any desired point and is of a diameter small enough to ofl'er suflicient resistance to the flow of the liquid therethrough, which results when the air becomes expelled from the tank 10, so that this flow is negligible.

The vacuum break before mentioned comprises the small pipe 17 between the inlet to the separating tank and the priming tank. This pipe is of a diameter sufiiciently small to reduce the leakage therethrough, when the pump is in action, to a negligible amount.

The novel means for expelling air from the priming tank during operation comprises a pipe 18 opening at or near the top of the tank 9 and connecting with an air ejector n the pump intake 7 at its other end. At this point there is placed a venturi 19 having openings 20 through its neck, and leaving a space 21 between its neck and the inside of the pipe 7. This novel ejector clears the priming tank of gas during the time the pump is bein operated.

In the modification shown at Figure 2, the pump, lift pipe, and separating tank arrangement is substantially the same as that shown in Figure 1 and the identical parts bear like reference numerals. Between the pump and the storage tank, however, there is inserted a' primary separation tank 21 connectedwith the priming tank by a p1pe 22 which is controlled by a valve 23 operable only by the pressure in the tank 10. T1118 pressure is transmitted to the valve mechanism by the conductor 25 and closes the p1pe 22 when the pressure reaches a predetermined amount. Inasmuch as pressure controlled valves are old in the art, and that any convenient type which will serve this purpose maybe used, the details thereof need not be described.

A vent valve 24, adapted to be closed when the liquid level in the tank 10 is above a predetermined point, permits the gas to escape 24 being closedby the rising of the liquid in the tank 10 causes a pressure to build up therein which actuates the valve 23, which in turn closes the by-pass 22.

Referring now to Figure 1, the operationrsaopaa of this device comprises several stages. Assuming that the amp is at rest and that the system is primed to the level L-L, the lift ppe will contain only air. If then, the pump started, it will tend to draw out the liquid in tank 9-. This willcreate sufiicient suction to raise the liquid in the lift pipe until it spills into the priming tank.

It is obvious that, as the liquid begins to spill into the tank, there will be a large percentage of ratified air in the tank 9. This quantity of gas will tend to increase until, as before explained, the pump intake is no longer flooded and the system becomes airbound. However as soon as there is a fiow created in the pipe 7, the venturi located therein will commence to draw the air from the upper part of the tank and eject it through the pump in a manner which will be well understood by those familiar with the pertinent art. As the pumping action contlnues, the percentage of air in the tank will become less and less until liquid will be drawn through the venturi through the pipe 18. This system is capable of expelling any normal amount of air or other gases which may be dissolved, suspended, or otherwise entrained in the fluid.

As soon as the liquid starts to rise in the tank 10, the air therein will be expelled through the vent pipe 16. It will be noticed that the pipe 15 enters the tank at a level substantially below the top of the tank in order to permit air or other gases to collect at the top. After all the gas has been expelled from this tank, the liquid will flow through the pipe 16, which may be led back to the source or to any suit able sewer or drain as desired. This pipe is of such a small diameter and is preferably made long enough to offer enough resistance to the flow, so that the leakage therethrough when the system is deaerated will be negligible.

Upon the stopping of the pump, the column of liquid in the lift pipe and the pressure of the liquid in' the storage tank will tend to siphon out the system until the air will bubble through the vacuum break 17 which is connected between the priming tank and the pump outlet at a level approximately the top of the priming tank. As soon as the system has been emptied to -this level, any air whichwill have been drawn in through the vent will be drawn through this pipe and bubble through the liquid in the tank 9 to break the suction, as explained in Patent No. 1,410,27 2. This obviates the draining of the pump and a part of the pump outlet. The resistance of this pipe can also be made great enough to render leakage through it negligible when the system is in operation.

Referring now to Figure 2, the modification here disclosed operates in a different manner. Assuming a sufliciency of liquid in the tank 9, the initial operation is the same dition into t e prima as that ,of Figure The pump then start to pum liquid and air in a mixed conseparatin tank 21'.

The entrained air will freed an naturally .pass on to the tank 10, but some substantially air-free liquid will be pumped back to the tank 9 to'entrain more air, which will also be separated. If enough liquid remains in the system to fill the tank 21' so that it will spill through the ipe 22, which is of higher resistance than t e main line, the system 7 willbe self priming. As the liquid circulates Y pipe 22, and back to the the tank 10 drops from the priming tank through the pump and "priming tank, entraining air each time, w ich is also separated each time and forced into the tank 10, the effect produced is equivalent to the pump pumping out the air from the tank 9 into the tank 10.

As the air enters the tank 10, it escapes .through the vent 24. As long as the valve 24 is open, it is obvious that substantially no pressure will be developed at the top of the tank 10 to close the valve 23. The valve 24 is designed to be operated by the liquid level in the tank and be substantially independent of the pressure in the tank. When the tank becomes substantially full of liquid, the valve 24 closes causing the pressure to build up, thus closing the valve 23 and permitting the system to function to deliver water. It has been found in actual practice that any normal amount of air which may collect in the tank 9 will be entrained in the flow and collect at the top of tank 10. When during normal pum ing the liquid level in elow a predetermined point, because of accumulation .of air or other gas the valve 24 blows off and lets substantially all the air out of the tank. The rising of the liquid in the tank attendant upon exulsion of the air again closes the valve 24. %y this arrangement the system becomes antom'atically self deaerating. As long as some air exists in the priming tank a portion of it will be entrained in the liquid flow and collect at the top of the storage and separating tank. This gas will collect here to cause the valve 24 to open before the system becomes air bound.

When the pump is stopped the liquid col-' umn in the lift pipe 11 and the pressure of the liquid in the storage tank start to drain out the system, as is the case in the mechanism shown in Figure 1. This may tend to create a partial vacuum at the top of the tank 10, vbut the liquid level is thereby lowered and, the valve 24 opens and breaks the'vacuum. When the liquid is drawn to the level of the pipe 22, the valve 23, having been opened by the decrease in pressure in tank 10, permits the pipe to function in the same manner as the vacuum break 17 in Figure 1, and the system is ready to be operated again.

Air or other gases in the priming tank are detrimental. If the (presslilre flefquired to int e pipeis lift the column of liqui ten pounds, or two thirds atmospheric pressure the pressure in the priming tank as the liquid starts to spill in must-be one third atmospheric pressure or five pounds. Inasmuch as the volume of a gas varies inversely as the pressure applied, any gas which may exist in the priming tank at the beginning of the priming operation will occup three times its normal volume as the liquid starts to spill into the priming tank from the lift pipe. It follows then, that, in addition to the liquid necessary to raise the liquid up the lift pipe, an extra quantity at least three times as great as the volume of air initially in the priming tank will be necessary. This, of course, requires a larger tank than if all the air could be excluded therefrom.

Thus it is quite apparent that the percentage of the gas which must remain in the priming tank is an important factor in determining the size of the tank. Also, it isan equally important factor in determining how much pumping the pump must do before it can begin to supply the dispensing system with liquid. Therefore, this gas percentage is a large factor in determining the over-all efiiciency of the pump as well as the size of the tank and hence the cost of the apparatus. The higher the lift the greater the effect a given percentage of air in the priming tank will have in determining the size of the tank. Thus, the dome-shaped top for the priming tank, which is a part of the present invention, serves a novel and useful purpose.

It is apparent that various modifications and arrangements may be made in the disclosed structure without deviating from the scope of the present invention. It is also apparent that the position of the gas and liquid may be reversed and the flow of the gas be used to eject any liquid which might collect in a storage tank of some kind. It is, therefore, not intended that the scope of this invention be limited to the above disclosure, but that it shall be limited only by the scope and spirit of the appended claims.

I claim a 1. In combination, a centrifugal pump, a container having an upper opening connecting with a liquid source and a lower opening connecting with said pump by a pipe, a Venturi nozzle in said pipe constructed to leave a space between its neck and said pipe, and having openings in said neck communicating with said space, and a fluidconductor between said space and the upper portion of the container. I

2. In combination in a pumping sys em comprising a container for liquid and a storage tank, a centrifugal pump, a pipe connecting the intake of the pump to the container, said pump discharging into the tank, a venturi fitting snugly within the pipe and having are its restricted portion aced away from the surrounding wall of t e pipe, the venturi havin an opening communicating .with the space Ixatween the restricted portion thereof and the pipe, and a conduit establishing communication between the container above the level of the li uid column and said space.

i 3. In combination in a umping sys'te a priming tank, a source 0 suppliy of liqul communicating with the tank a jacent the top thereof, a storage tank above the primingtank, a centrifu connecting the inta e of t e pum to t e lower portion of the priming ta a discharge pipe connecting the discharge of the pump to the storage tank remote from the top thereof, a venturi fitting snugly within the intake pipe and having its neck portion spaced from the surrounding wall of the pipe and provided with an opening extending therethrough, a conduit connecting the space between the neck portion of the venturi' and the pipeto the upper portion of the priming tank, and a conduit of restricted area connecting the discharge pipe to the upper portion of the priming tank.

4. In combination in a tank structure, a hollow body provided with top and bottom heads, an intermediate head within the body and separating it into an upper tank and a lower tank, said intermediate head being of substantially concavo-convex cross-section with its under surface concaved, and a pipe extending through the wall of the upper tank above the intermediate head and opening throu h said intermediate head into the lower tan said pipe being secured to the intermedia e head and to the wall of the upper tank, the inner end of said pipe being substslzlrligtially flush with the roof of the lower ta a In witness whereof, I hereunto subscribe my name this 12th day of May, 1926.

FREDERICK H. BRADFORD.

lpum an intake pi e

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