US2163951A - Separator for self-priming pumps or the like - Google Patents

Description

June 27, 1939. LA BOUR SEPARATOR FOR SELF-PRIMING PUMPS on THE LIKE Filed Nov. 5, 1957 3 sheetsv-sheet 1 June 27, 1939. H. E. LA BOUR SEPARATOR FOR SELF-PRIMING PU MP OR Til! LIKE Filed Nov. 5, 1957 --s Sheets-Sheet 2 m 21, 1939. H. E. LA BOLIR 2,163,951

SEPARATOR FOR SELF-PRIMING'PUMPS on THELIKB 'Filed .Nov 5, 19:57 f s Sheets-Sheet 3 casing.

leases June'27, was

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s'EPARA'roit FOR SELFJ-PRIMING PUMPS on THE HarryE. La. Bout, Elkhart, Ind. Application November 5, 1937, SerialNo. 172,945

' 6 Claims.

-My invention relates to centrifugal self-prim: ing pumps and is particularly concerned with the means for releasing the. gas entrained in the charge of workingliquid during priming.

Self-priming centrifugal pumps usually provide in their structure, or associated structure, means for retaining a charge of working liquid which is employed as a medium for withdrawing air or other gas or vapor from the suction line in suffieient amounts to cause the liquid to rise into the pump.

This charge of liquid, during priming, is involved in three important functions. First, it is charged with air to form a working fluid or mixture Within the pump casing. This fluid or mix.-

ture has sufficient density to develop the necessary discharge pressure required to permit carrying out of the air in the pump casing and the suction pipe against at least atmospheric pressure, or whatever head the pump may be working against. Second, the charge Of liquid provides a pool or body which serves as a reservoir to which the stream of discharged mixture is added and from which the stream of return or priming liquid is withdrawn. Third, the body or pool of liquid permits of the separation of-the entrained gas whereby the gas is rejected or eliminated. Additionally, this body or pool or" liquid serves as a liquid seal, preventing the entry of air or other gas into theinterior of the pump The effectiveness of the priming action de-- pends upon the balanced relation of the various actions above enumerated. The mixing of the liquid with gas in the pump casing is effected by the rapidly rotating impeller and is rather easily attained because of the positiveeffeet of the impeller. I The separation of the gas from the liquid is usually carried on in a chamber known as a separator, which, during priming, retains the charge or pool of liquid above referred to. If

all gas could ,be eliminated from the return or priming liquid the rate of priming would be greatly enhanced. In fact, the chief practical obstacle to effectiveness in priming is the difficulty of eliminating the entrained gas from the liquid which is returned to the pump casing.

-This is apparent from the fact that any en the return passageway. However, the greater the volume of liquid required to be maintained in the separator, the more diiii'cult it is to secure rapid elimination of the entrained gas. In the early form, of pump shown in Patent 5 No. 1,578,236 and wherein the separator is'disposed above the pump, gravity separation, i. e., rise of the entrained air by difference in gravity to the releasing surface of the liquid, was chiefly relied upon. j i 1o For certain situations, such as low head mine work, the top type separator required too great head room, and I thendeveloped the side type separator, as disclosed in myPatent No. 1,908,635.

In this typev of separator theliquid in the 'sepa-' 16 rator was caused to whirl on a vertical axis by 'ing priming, I. have devoted much study tdthe provision of separators for various designs of pumps, and call attention to separators shown in the following patents issuedto me:

In Patents Nos. 1,915,678 and 2,019,143 Zapplied the principle of separation by centrifugal action in a top type separator, the whirl occurring on a horizontal axis and lying in substam tially a vertical plane. i

In Patent No. 1,966,896 I combine the action 013 5 centrifugal separation with gravity separationin a separator surrounding the pump casing.

In Patent No. 2,005,466 I employed a helical travel of the mixture on 2. horizontal axis, supplementing the same with gravityseparation in a distinct and separate part of the separator.

While these various forms of separator and their separating action gave'better separation at least for certain purposes, it is to be observed that they became more complex and more expensive to construct. i

The object ofthe present invention is to provide a separator of simple, inexpensive construetion and 01' good emciency. The present separator is the first to take an entering vertical iiow of mixture, spread it out in a relatively thin stream moving in a horizontal whirl on the inner cylindrical walls, and then more or less retarding or stopping the whirl enough to insure sealing the outlet and causing the liquid to flow down 55 and out of the separator in a substantially vertical direction.

A further object is to teach a method of separating gas from liquid in a separator particularly adapted for centrifugal pumps of the selfpriming class.

A further object is to provide a top type separator for pumps of the class herein referred to, applicable to pumps of present construction to improve the effectiveness of pumps of this class,

both in priming and in liquid pumping.

A further object is to provide a separator, for pumps of the type herein referred to. which has the ability to clean itself and avoid clogging with entrained solids. Also, this separator tends to prevent the return of solids from the bottom of the separator into the pump casing during priming or backflow which occurs upon stopping the pump.

Other and incidental objects will be apparent from the following detailed specification and the appended claims.

Now in order to acquaint those skilled in the art with the manner of constructing and operating a specific embodiment of my invention I shall describe, in connection with the accompanying drawings, one form in which my invention may be embodied.

In the drawings:

Figure 1 is a front elevational view of a separator superimposed upon a part of the pump casing;

Figure 2 is a top plan view of the separator of my invention;

Figure 3 is a side view of the separator taken from the right of Figure 1;

Figure 4 is a vertical section taken on the line 4ii of Figure 3;

Figure 5 is a horizontal section taken on the line 55 of Figure 4, looking downwardly; and

Figure 6 is a diagrammatic side elevational view illustrating the component parts of a complete self-priming pump.

In the attainment of the above objects I provide a novel method of separation which involves the employment of a body of fluid whirling on a vertical axis to produce inertia separation or centrifugal separation. This vertical whirl is, however, not a free whirlpool, for reasons later to be explained, but a whirl with a certain amount of breaking or retardation, which has the dual effect of preventing too deep a vortex and also of tending to pile up or gather the liquid at the mouth of the return passageways. Thereby the orderly separation and return of priming liquid is assured over a fairly wide variation of operating conditions such as speed, density of the liquid, volume of liquid, vacuum attained during priming, etc.

Referring first to Figure 6, I have here shown a self-priming centrifugal pump which comprises the main parts as follows. The pump casing i has its inlet at 2 to which there is connected an inlet trap 3 having inlet connection 4. The pump casing I has a discharge connection 5 which is illustrated in detail in Figure 1 and this discharge connection is coupled to the separator 6 which has at its upper end the outlet connection I. The pump casing I contains a suitable rotor or impeller provided with vanes 9 which, in this case, sweep the inside periphery of the channel in which the blades 9 run. The inner periphery Id of the channel, in which the blades 9 run with relatively small clearance, communicates through two tangential passageways i2 and with outlet openings at the top or the pump casing where the connection 5 is made. The passageway i2 is the main discharge passageway and the passageway I3 is the auxiliary discharge passageway which, during the priming operation, serves as the return passageway for the priming liquid to maintain the circulation of liquid back into the pump casing for discharge of the mixture through the main passageway 12.

The casing l and the separator 6 have meeting flanges i4 and 15 for convenience in construction and assemblage of the parts. Obviously, the separator may be cast as an integral part of the back plate of the casing, or the structural arrangements may be otherwise varied without departing from the present teaching.

The separator 6 comprises, in the form shown, a hollow cylindrical body portion providing a separating and discharge chamber. A top outlet connection I may be disposed in any horizontal direction desired. Here it is shown as facing forward parallel to the axis of the impeller shaft 16. The outlet connection 7 comprises a tubular passageway ll formed through a neck l8 and herein shown as surrounded by a clamping flange 9 for making connection with the discharge pipe of the pump, which may be led to any suitable point, preferably to a point communicating with atmosphere. The top of the separator is provided with a threaded opening 2| for filling purposes and this opening 2! is normally closed by a screw plug shown in dotted lines in Fig. l.

The lower end of the cylindrical body portion of the separator G merges into a conical wall 22 and at the central part of the conical section 22 is provided the passageway 23 matching with the main discharge passageway 12 in the pump body. A tubular extension 24 contains a return passageway 25 which matches with the auxiliary discharge passageway 83 in the pump body. These passageways 23 and 25 form openings through the mating flange l5 so that when the flanges it and I5 are clamped together the separator communicates with the interior of the pump casing through the main discharge passageway I2, 23 and the auxiliary discharge passageway i3, 25. Obviously, any of these parts may be formed as separate pieces joined together for convenience in manufacture and assembly.

Within the separator 6 there is formed an integral inclined vane 27 which defines a passageway 28 forming a communication between the opening 23 and the interior of the separator 6. This inclined vane has its lower edge joined to the conical portion 22 along the curved intersection 29 indicated in Figs. 2 and 3 in dotted lines. The edge of the vane 21 indicated by the intersection of the vane with the cylindrical portion is designated by reference numeral 3%. The free edge of this vane is indicated by reference numeral 32. This vane may be fiat, that is, planar form, or it may be warped, as desired. Its function is to impart a tangential direction to the mixture entering through the central opening 23 under the vane 21. In other words, the liquid discharged through the main discharge passageway l2 enters through the opening 23 in the bottom of the separator and is directed by the vane 21 in a spiral and subsequent helical path around the inside periphery of the separator 6. Thus the axial entry is directed into tangential travel.

This tangential travel inside of the circular chamber would tend to form a whirlpool with a deep vortex at the center. Depending upon the velocity of discharge and the quantity of liquid forming the charge of priming medium, the vortex might extend down far enough to produce a relatively thin layer of liquid over the opening 33 (see Figure 5) where the return passageway 25 opens into the interior of the chamber 6. Hence, under certain conditions, particularly where a relatively high suction is being created inside the pump casing, a tendency is produced for the atmospheric pressure suddenly to strike through the relatively thin layer of liquid and travel down through the opening 33, passageways 25 and I3, into the interior of the pump casing, destroying the vacuum. The whirling motion of the liquid to free the same of the entrained air is highly desirable, as it performs two useful functions, first, the centrifugal efiect of forcing the air to the center of the whirlpool and second, giving a greater area of free surface from which the gas can escape from the liquid. How-- ever, an: uncontrolled vortex is undesirable for the reasons above stated.

A vertical rib or baflle 34 extends approximately radially from the inner wall of the separator 6 in a vertical direction. This baflle or rib performs two useful functions. The first is to create a region'of pressure of liquid, by impingement of the liquid stream thereagainst, directly over the opening 33. That is to'say, considering the direction of rotation of liquid charged with air in the separator, the tendency of the lighter liquid mixture is to go to the top, and the denser or less gas-containing liquid to gravitate toward the bottom of the separator, but the tangential motion imparted by the vane 2'! causes both parts of the liquid to move in substantially a helical or spiral path. This motion of the liquid represents a certain kinetic energy which, by impingement against the vane fit, is transformed into pressure upon the mouth 33. This insures sealing of the opening 33 with liquid and also performs the useful function of putting a braking or amortizing effect upon the otherwise uncontrolled whirling of the liquid. The form of this vane or baflie 34 may be controlled to produce the desired efliects above indicated, or'either of them.

It will be seen in Figure 5, as indicated by the arrow 36, that the spiral and helical flow produces an impingement upon the side of the rib or baille 3d which is adjacent the opening 33, whereby to create pressure at this point. The liquid not so engaging the vane or baflle 34 is forced radially inwardly in order to continue its rotary travel. By this arrangement a control of the vortex action is secured and even if the retained priming liquid is below normal, as sometimes occurs, the piling up or impingement against the vane 34 and consequent sealing of the port 33 is an important aspect of the present invention. Also, it may be seen that the pump may be designed to prime on a smaller charge of liquid under these conditions. The operation of the pump, in brief, is as follows:

Assuming that the pump has ceased pumping liquid, and liquid has been allowed to how back through the connection I, separator 6, pump casmg l, through the trap 3 and back through the suction connection 4 to the point of breaking the suction existing at the top of the trap, a

certain charge oi liquid will be retained in the trap and in the pump casing. This, as a maximum, is represented by the level an which is the bottom of the suction connection it. As-

suming that auction pipe is sealed with water and that the shaft it is rotated, liquid will be drawn from the intake trap t and discharged through both passageways it and it and driven into the separator 8. Immediately thereafter. since the impeller cannot develop suficient pressure on air alone, liquid will return through the port 33, passageway 25 and it, into engagement with the impeller 8, whereupon a mixture of gas and liquid is formed of a density great enough to create a discharge pressure to prevent return of liquid through the passageway 52. The pump then continues to circulate the priming liquid, driving mixture out through the passageway iii and receiving priming liquid tract: through the passageway iii. The stream of discharge minture passes up through the central passageway 23 in the bottom of the separator t, under the vane 21, where it is directed in a spiral path as indicated in Figures 4 and 5, giving to the body or pool of liquid in the chamber ii a whirling motion, the whirl being on a vertical axis. This creates a desirable separating action for separating the gas from the liquid, due both to the centrifugal eflect and to the increase of area, as well as the thinning of the layer of liquid, that is,- reducing the distancewhich a bubble of gas must travel inorder to reach a surface where it can free itself. The uncontrolled whirling of the liquid is prevented by the battle tit, which creates aplenum by impact of the liquid upon the port 33. The liquid piles up along the rib or baffle 34 and tends to fall into the port 33, where it flows back by way of the passage way 25, i3 to maintain the circulation of the pump during priming. When the priming operation has proceeded to the point of drawing liquid from the source. in through the intake trap 3 into the pump chamber l to fill or substantiallyfill the impeller 93, the pressure developed upon the secondary orreturn passage or throat i3 is great enough to prevent the re turn how of liquid through this route and liquid is discharged through both it and it into the separating chamber in the separator ii. Due to the action of the vane or bathe 3 in braking or amortizing the whirl, and due to the outflow of liquidat the port as distinguished from the previous inflow, a greater iii-airing action or amortization of the whirl is produced by the flow of the secondary passageway, whereby the losses which otherwise'would occur due to the whirling action oreddying is reduced when the two throats are discharging liquid. The vane or battle it may be inclined in a direction opposite to the whirl created by the main discharge stream so that the two effects can be caused even more to counteract each other. This is a refinement, and is optional. When the pump thus pumps liquid the separator t fills with the liquid and discharge occurs at the opening it in the discharge connection i.

Since the member 6 whichI have above termed the separator chamber serves the dual function of a separator chamber during priming and a means for joining the two discharges from the throats i2 and it during liquid pumping, it can be seen that it performs an important function in the operation of a self-priming pump unit. In

other words, the action or the impeller and its casing l. in conjunction with the action occurring in the separator 55 during priming and during liquid pumping, involves an important cooperation, each being influenced by the operation of the other.

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I do not intend to be limited to the specfic details shown and described, as the above specific embodiment is given by way of example and illustration, rather than of limitation.

I claim:

1. For use as a part of a self-priming centrifugal pump, a separator comprising a tanlclike substantially vertical cylindrical shell having a top outlet to permit the escape of gas during priming and for the discharge of liquid after priming is completed, a vertical inlet at the lower end of said shell, a vane in said shell for causing the vertically entering stream of mixture to travel about the inner periphery of the shell in a horizontal loop, an outlet for the fiow of priming liquid from the separator back to the pump, and a battle disposed in relation to the latter outlet to cause a piling up of the whirling liquid at said latter outlet to seal the same with liquid during priming.

2. A separator and discharge chamber for a self-priming centrifugal pump comprising a substantially cylindrical shell having a main outlet connection at its upper end for the discharge of gas during priming and the discharge of liquid during liquid pumping, said shell being disposed with its longitudinal axis substantially vertical, inlet means at the lower end of the shell arranged to direct an entering stream of mixture during priming substantally tangentially to the inner periphery of said shell to produce a horizontalswirling of the mixture in the chamber, an aum'liary passageway in the lower end of the chamber and a bafiie adjacent said auxiliary passageway extending in a direction transverse to the direction of swirl of the liquid, said battle being adapted to be engaged by the swirling liquid and thereby causing the liquid to pile up and seal the auxiliary passageway during priming.

3. A separator and discharge chamber having a vertical axis and an outlet at its upper end, means to discharge a vertically entering stream of mixture of gas and liquid into the separator ber, an outlet for liquidiroin which the gas been separated and a vertically extending va e behind said outlet with reference to the direct l of motion of the swirling body, said vane being adapted to be impinged by the swirling body for creating a liquid seal upon said outlet.

A separator for a centrifugal self-prim pump comprising a shell of substantially cylind cal form arranged with its longitudinal axis veltical, an outlet at the upper end, a main inlet disposed substantially axially itt lower on the shell. and a priming outlet 1- i g from peripheral part of the lower ens oi ti means for directing the vertice 'y entel.. of mixture substantially tangenti walls of the shell in a generally ho tion and a ballie disposed in dire c the priming outlet, said baffle tending to ins sealing of said outlet with liquid and limiting the whirling of the liquid within the separator.

5. The separator of claim 4 wherein the lower end of the shell has a conical portion main inlet disposed at the apex of the cone and wherein the means for directing the st am of mixture comprises a vane extending from the conical wall to the cylindrical wall of the shell.

6. A separator having a cylindrical shell with a vertical axis, a top outlet, a mixture inlet lor leading mixture generally vertically into the shell and having means for directing the same in a thin layer whirling horizontally on the inner cyindrical walls, a vertically disposed baffle on the inner wall of the shell and a generally vertically downwardly directed outlet having an opening into the inside of the shell in front of said bafile with reference to the direction of motion of the whirling layer.

its,

"EARRY BO-UR.

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