US2297001A - Self-priming centrifugal pump - Google Patents

Description

Sept."29, 1942. H. E. LA BOUR PRIMING CENTRIEUGAL PUMP SELF- 4 sheets-sheet 1 Filed March 17, 1959 Sept. 29, 1942. H, 5 L BOUR 2,297,001

SELF-PRiEMING CENTRIFUGAL PUMP Filed March 17, 1959 4 Sheets-Sheet 2 Q Q In men 'Lorv Sept. 29, 1942.

|-|. E. LA BOUR SELF-PRIMING CENTRIFUGAL PUMP 4 Sheets-Sheet 5 Filed March 17, 1939 km I I [721)872 Z 07" 1701 734? lag 50447.

P 1942- H. E. LA BOUR 2,297,001

SELF-PRIMING CENTRIFUGAL PUMP 4 SheetsSheet 4 Fil ed March 17, 1939 Patented Sept. 29,- 1942 UNITED STATES PATENT OFFICE 2,297,001 SELF-PRIMING CENTRIFUGAL PUMP Harry E.,La Bour, Ell rhart, Ind, Application March 17, 1939, Serial No. 252,339

22 Claims.

My invention relates to centrifugal pumps. While the invention primarily and mainly relates to centrifugal pumps of the self-priming type, certain features ofthe invention, as will later appear, have a wider application than this particular type. Further, while I have shown herein a self-priming centrifugal pump of the type wherein recirculation is inherently controlled by the pressures developed by the fluid mixture at or near the periphery of the impeller during priming, according to the principle disclosed in my Patent No. 1,578,236, it is to be understood that certain features, as will later appear, are applicable to self-priming pumps of other types. Also, it is to be observed that while I have shown a specific 'form of impeller housing employing two pairs of throats, this feature may be varied, as certain advantages of my invention may appear in pumps employing one or more pairs of throats or single throats in lieu of pairs.

The present invention constitutes in some respects an improvement upon my copending application, Serial No. 174,522, filed November 15,

One of the-d ifliculties of a vertical pump is the extended vertical dimension which that type of structure tends to require. If the driving motor or driving means'be based upon the top of the pump,'the difficulty of adequately supporting the shaft arises. Also, with the usual packing glands, space is requiredfor servicing, and this makes a direct mounting of the pump upon the motor difficult and cumbersome. While any suitable means for mounting the driving means or motor fixedly relative to the pump may be employed, a highly desirable and advantageous form of mounting is disclosed and claimed in my copending application Serial No. 273,718, filed May 15, 1939.

In my copending application, Serial No. 174,-

522, above referred to, I have disclosed a novel means of packing the impeller shaft with the liquid being pumped or employed for priming, Sealing' of the'shaft with liquid requires a certain arid continuous supply of liquid to the gap between the'shaft and the surrounding sleeve or casing. The liquid tends to be thrown away from the shaft by centrifugal force, thereby reducing the effectiveness of the seal. Also, the problem of providing suitable space within which the seal may be effected, presents a serious difficulty in the construction of a compact vertical P p- According to the present invention, I have a provided a novel method of compelling the liquid to hug the shaft,.so that the tendency for the liquid to be thrown away from the shaft by the centrifugal force of the spinning shaft is not to be limited to pumps of high shaft speed, a as the advantages appear at all practicable speeds. This liquid shaft seal is the subject of divisional application Serial No. 425,836, filed January '7, 1942.

Along with the means for compelling the sealing liquid to hug the shaft, there is provided herein means for insuring an adequate and constant supply of sealing liquid to the seal.

A further problem which I have encountered in the development of the liquid type of shaft seal is the necessity for certainty of disposal of the necessary outflow or wastage of sealing liquid. In my prior pump, I extended a tubular passage from the upper end of the sealing sleeve to the exterior of the pump, and a surface runoff on the top wall of the pump. In the present construction, I have extended the bearings for the shaft down below the top wall of the body. Absolute assurance that the overflow of liquid cannot, under any circumstances, rise into the bearings must be had, and to this end an open gutter-extending off from the upper end of the sealing sleeve is provided.

Another problem which is acute in the vertical form of'pump is the provision of adequate means for maintaining suflicient liquid in the pump to insure an adequate supply of priming liquid to perform the operation of priming. This is a particularly pressing problem in a compact high speed high capacity pump such as herein disclosed. 1

The present pump provides a compact body, desirable; for obvious reasons, with the intake trap at the center and the separator surrounding the same. The circular type of separator is particularly desirable for the multi-throat de-' sign because it permits separation by centrifugal force or vortex action, herein designated as dynamic separation, but where the impeller chammultiple throats, it tends too easily to empty itself of the liquid necessary to be retained for priming upon stopping the operation of the pump.

The limited-space at the center of the body for the intake trap space presents a serious problem of how to keep the intake trap from being emptied by collapse of suction in the suction pipe, particularly where the latter is of considerable volume. The present pump will quickly draw .a high vacuum, and this intensifies the difficulty.

Accordingto one phase of the present invention, the top of the trap is extended above the shaft seal and above the separator to provide the added capacity. -To insure that liquid escaping from the shaft seal will not enter the bearing which extends below the top of the trap, an open channel extends out of the pocket so formed. To insure that the trap of such relatively limited capacity and of such short vertical height is not emptied by the collapse of suction in the suction pipe, or rapid return flow upon: stopping of pumping, the trap is divided into two portions, one of which, being preferably of less capacity than the other, may be emptied by the outrush of return liquid and the suction broken without depleting the supply of liquid retained in'the other or main portion of the trap. This main or retaining portion is provided with a restricted communication at its upper end, to the intake duct to facilitate filling of this portion while retarding emptying. A free communication of the two portions with each other exists at their lower ends.

.In brief, the vertical design of self-priming pump presents problems of shaft sealing, retention of priming liquid mounting of the shaft and motor, and compact arrangement of the parts, which are wholly new and not solved in the horizontal design of pumps, and not solved anywhere in the prior art.

The present form of pump is particularly applicable to chemical service. Such a pump must be adapted to be constructed of high chrome a1- loys. Such alloys are diflicult to cast and to machine. All' parts subject to corrosion are made replaceable individually at minimum expense and inconvenience.

The basic structure of the present pump is such that a variety of impeller casings and impellers may optionally and interchangeably be employed. Thus various throatings and impeller shapes and designs may optionally be provided with a minimum stock of parts. While the present construction shows an open impeller, a closed impeller withappropriate housing and throating may be substituted.

The present pump is particularly intended for use above the level of liquid to be pumped, and under that circumstance the liquid packing is preferably employed. It is to be understood,

however, that the other features of the present pump may be employed when the pump is located below the level of liquid to be pumped, and a conventional or preferred form of solid packing employed.

Also, while I have shown the impeller shaft as supported in -a driving shaft having bearings borne directly upon the body of the pump, it will be understood that this feature may be varied under certain circumstances without varying the fundamental characterof the pump.

.The-chief'object of'the present invention is to provide a compact, efllcient vertical pump ca- A further specific improvement resides in the means for supplying the .liquid seal. The supply duct is so constructed as to be self-cleaning and normally non-clogging. Access to the interior thereof is provided through an opening which may serve as a"core support during casting.

A further specific improvement is the provision of a simple effective way of forming and mounting the top plate of the impeller housing upon the lower end of the annular trap wall by a shrink fit.

Further objects and improvements will be apparent from the following specification.

In the accompanying drawings, which form a part of the present specification,. and in which like reference numerals refer to like parts,

Figure 1 is a vertical axial section through a Figure 5 is a horizontal cross-section taken on the line 5-5 of Figure 1;

. Figure 6 is a vertical section, on a reduced scale, taken on the line 66 of Figure 5;

Figure '7 is a top plan view of the bearing structure as viewed from the top of Figure 2; and

Figure 8 is a cross-sectional view of a detail.

The main parts of the pump are a main body casting I, an impeller housing plate.2, a closure plate 3 which forms not only a closure for the main body casting l but also completes the impeller' housing for the impeller 4, a bearing bracket 5 for supporting the impeller shaft 6 being mounted in the upper part of the main body casting I. The parts I, 2, 3, 4 and 5 are preferably all castings. With the main. body casting l, a wide variety of impellers 4 and c0- operating housing and closure plates 3 may be employed to provide different forms of impellers and throatings as may be desired.

The above described parts define three main coaxial chambers, namely, the impeller chamber 1, the discharge chamber 8, and the inlet chamber 9. It will be observed that the discharge chamber 8, which serves also as a gas and liquid separator during priming and as a trap to retain liquid when the pump stops, surrounds the 36 that is on the wall 39 may, by gravity, run" formed'in the housing plate 2. Thus a large part of the capacity of the trap or inlet chamber is disposed above the tubular portion I 6 and above the discharge chamber, as will be apparent from Figures 1 and 2. The main body portion I is a casting comprising the outer peripheral wall l3, preferably in theform of a cylinder, although this is optional as the wall might be in the form of a square or polygon if desired. The lower end of the wall I3 is preferably constrictd slightly, as at 14, and terminates in a clamping flange I I5 which preferably also, but not necessarily, is circular. The wall 13 extends upwardly to a horizontal top wall l6, to which it is joined, preferably by a suitable fillet, that is, a rounded corner, for appearance and facility in casting. A short tubular inlet neck 11, provided preferably with a flange l6, provides an inlet passageway 19 through the wall l3 and into the inlet chamber or trap 9. Similarly, a short tubular neck 26, preferably provided with a flange 22, provides a discharge passageway 23 which communicates with the separator space 6. An annular horizonal wall 24, more clearly seen in Figure 2, at its outer periphery joins integrally the outer wall I3 and it, in turn, is connected through a suitable fillet or curved annular wall to the tubular depending neck.,25 which defines the lower part of the intake trap as designated by the reference numeral Hi. The top wall l6 of the main body I has a pocket or depression 26 which is formed by a conical annular wall 21 which is joined integrally to the top wall l6 and has a portion .26 terminating in a bolting flange 29 extending above the said top wall 16. The top of the inlet neck I1 is joined directly to the extension or neck 26 at one side, as a matter of convenience in construction. The shaft bearing bracket 5 'has a radially extending flange 36 which matches with the mounting flange 29. Suitable clamping bolts 33 hold the bearing bracket 5 to the -main body casting l. The bracket 5 is piloted, as at 34 in Figure 4, into a short cylindrical piloting bore 35 in the top of the cup or depression 26, to hold these parts together securely in alignment. The pump may be supported by a bracket clamped .to the top of flange 39 or it may be supported in any other suitable manner.

The bottom of the pocket 26 communicates with the outside of the main body casting I through an open cut or channel, as will be seen more readily from Figures 2 and 5. This open cut or channel 36, which provides free and open communication with the inside of the pocket 26 to.atmosphere, is provided for the purpose of insuring free overflow for any liquid coming up along the impeller shaft 6, as will be described more in detail later. There is an opening 31, as shown in Figures 2 and 5, in the side walls 21 of the pocket 26, and the vertical or substantially vertical walls 36 which, at their upper ends, join the top wall [6, at their outer ends join through the opening 46 into the pipe connection 42.

There is an integral tubular extension 41 which provides a barrel for housing a liquid seal sleeve 46 surrounding the shaft 6. This barrel 41 is divided by an inwardly extending flange wall 49 into two functionally separate chambers, namely, the upper or drain chamber 56 and the lower or liquid supply chamber 52. A'suitable packing 53, disposed in an annular pocket or recess in flange 49, tends to maintain a substantially tight joint with the sleeve 46 so as to seal off the two chambers 52 and 56 from each other.

There is a discharge or overflow passageway 54 from the overflow chamber 56 to the flanged neck or pipe connection 42. This passageway EL is defined by an integral tubular coredpassageway the upper wall of which is thesame as the bottom wall 39 of the draining groove 36. This passageway 54 is substantially oblong in cross section. The form thereof is optional. However, it provides free communicationbetween the discharge or overflow pocket 56 and the discharge or ov erflow pipe 44 extending sageway 56 extend out to the outer peripheral wall 13, where an opening is provided, which closed by a pipe plug 59. This opening 60, which is closed by the pipe plug 59, is a filling opening and it deflnes the level atwhich liquid will stand when the pump is initially filled for operation. This level, it will be observed, is substantially at or slightly below the drain or overflow duct the side wall l3, and at their lower ends join the uid-running out along the bottom ofthe groove 54, whereby a fllling of the pump to the level of the bottom of the opening 66 does not tend to escape by gravity through the shaft seal and out the overflow or waste duct 54. The supply passageway 56 opens downwardly at the opening 62 ('see Figures 2 and 3), so that the duct may be supplied with liquid even at a minimum of liquid level in the separator space 6. The opening 62 is substantially non-clogging and it opens at the point where the liquid isdensest and, during priming, has the maximum swirl. The passageway 51 is a liquid overflow or return passageway from the liquid supply chamber surrounding the sleeve 46. The liquid sealing sleeve is provided with an annular shoulder 63 at its lower end, and this flange is drawn against the A which forms a very effective seal.

of liquid pressure along the surface of the shaft produced by this arrangement makes is possible.

thrown off by the slinger ring may drain into the bottom of the pocket 26 and flow out along 'the wall 39 to the opening 46 and be conducted off through the drain pipe 44.

The sleeve 48 forms a tight joint with the lower wall of the tubular extension 41 as by means of a flanged head- 63, and it-forms a substantially tight connection with the flange 49 by virtue of the packing 53 above described, so that the liquid supply chamber 52, which is put under discharge pressure 'when the pump operates to pump liquid, will be substantially liquid tight. Obviously, the details of securing the parts together and of securing the tight relationship above referred to may, optionally, be varied.

The sleeve 48 is bored to fit the shaft 6 without gripping it. That isto say, there is a small clearance between the bore of the sleeve 48 and the shaft 5. This clearance is a small annular gap which is made so small as to constitute a material restriction to liquid flow but which would not exclude entry of gas or air if no sealing liquid were supplied. A few thousandths of an inch clearance may be provided, depending upon the character of the liquid to be pumped, the entrained solids, etc. Near its upper end, and registering with the discharge or overflow pocket 50, there are in the sleeve 48 a series of slots or windows 10 and the inside of the bore is relieved at these windows 10. Any liquid coming along the shaft 6 and entering the relief pocket at the windows 10 is free to flow outward radially into the chamber or pocket 50 in the tubular extension 41 and to escape to waste through the pipe 44. Liquid tending to creep upwardly along the shaft 6 past the relief pocket and windows dance. k

This can be seen particularly if the shaft is slightly eccentric with respect to the surrounding sleeve with which a liquid seal is to be maintained. for there would be a crescent-shaped lacuna or passageway left open between the shaft and the rotating liquid in the sleeve if there were any lack of concentricity between the two.

In the arrangement which I have shown (see particularly Figure 3), the higher the speed of the shaft the greater the velocity effect which occurs in driving the liquid into the narrowing space between the wedge-shaped part. of the sleeve and the surface of the shaft.

The wedging action of liquid at each of the inclined vanes produces a longitudinally extending area of positive liquid pressure. This pressure tends to act in all directions and since it is restrained circumferentially of the shaft it tends to force liquid endwise into the gap. These ports and their inclined spaces are close "enough to each other and have an effect sufliciently far in a circumferential direction to produce the efl'ect of a complete circumferential ring of pressure at both the upper and the lower ends of the ports 15. That is to say, in effect there is a pump forcing liquid into the gap between the shaft 8 and the sleeve 48, both in an upwardly and in a downwardly direction from the region of the 10 must pass, first, the restricted gap in the upper end of the sleeve and then it will encounter the slinger ring 61, where it will be thrown joif within the surrounding slinger groove 66 in the nut 65.

-Within the supply pocket 52 the sleeve 48 has a relief groove 12 communicating with the window 14. A shallow relief groove 13 may be cut in register with the inlet passageway I5. This groove is optional. The lower relief groove 13 communicates through a series of tangential inlet passageways 15 .(see Figure 3) which permit liquid to-come into contact with the shaft, moving substantially tangentially in the direction of rotation of the shaft 6. The liquid contacting the shaft. adheres thereto and is dragged, by

ports 15.

Since this pumping effect produces a plenum of pressure at the surface of the shaft, there is a tendency-for liquid to be discharged longitudinally along the shaft through the'clearance. In order to avoid an excess of discharge along the shaft in the upward direction, where it would be constitute, in effect, a small multiple pump, forcing liquid inwardly into engagement with the "cylindrical surface of the shaft and providing an excess of pressure at the surface of. the shaft to provide a relatively short-liquid seal of great effectiveness. Heretofore, attempts toseal with surface of the shaft all the way around it be- The plenumwasted, I have provided, at a point slightly above this" liquid wedging arrangement, the relief windows 14 which permit excess pressure at the surface of the shaft to be relieved and to flow back into the liquid supply pocket 52. Obviously this latter is an expedient which, while advantageous, is not essential to securing the. wedging action against the surface of the shaft for sealing purposes. Y

The arrangement above described may obviously be varied in detail, but the wedging of the liquid against the shaft around the same has proven highly effective, and maximum suction which the pump may attain by virtue of its pumping and self-priming action is unable to produce any gas leakage along the shaft. I

, der to bring the bearing support sleeve 5 as far cause of the centrifugal effect of the shaft in down the shaft as possible, the sealing sleeve must be made as short as possible in order'to produce the minimum overhang or outboard length of the shaft 6.

The liquid seal sleeve 48, and particularly the ports I5 and the sealing portion of the sleeve below said ports 15 is disposedbelow the normal bottom of the ports 15, so that a liquid seal may be maintained on the lower end of the sleeve. For best results the liquid should be at a high enough head to insure filling the ports 15 and then the pumping effect of the shaft 6 and said ports 15 is insured. In earlier forms of this pump I have faced the inlet opening 62 forthe inlet passageway against the direction of rotation or swirl of liquid in the separator, so as to cause an impacting of the moving liquid upon said opening. It then acts as a Pitot tube to transmit liquid pressure to the chamber 52. That construction has a greater tendency to conduct entrained solids into the chamber 52.

Now I shall describe more in detail the pump housing and its throating.

The closure plate 3, to which reference has been made above, provides,,in a single casting, a closure for the lower end of the main body walls I9 as by means of the sealing flange 19 which cooperates with a gasket seat 80 on the bottom flange I to clamp a suitable sealing gasket 92 between the adjacent surfaces. The clamping ring 83, which may be of inexpensive metal as compared with the expensiv corrosion-resisting metals of which the above described parts of the pump may be constructed, cooperates with the flange I5 and the clamping bolt 84 to hold the plate 3 in place. The clamping ring 03 and the flange I5 may be registered by means of the registering groove 85 (see Figure 1). Then, by means of a locating pin 96, registration of the plate 3 with the body I may be secured without interfering with the seal at the gasket 92. The I annular wall 81 which joins the sealing flange 19 is sloped to substantially a low point at 'the drain plug 88. This annular wall.8'| may be substantially horizontal or it may be tapered upwardly.

In the present case there is a cylindrical circular wall 89 by which the annular wall 91 joins the bottom housing plate 90. The plate 90 forms a part of the main impeller housing, constituting, in this case, the bottom wall, since the impeller is disposed in a horizontal plane; Th central part of the wall-90 is bulged downwardly at 92 to provide a pocket for the hub of the impeller I tohouse both the fastening nut 93 and the adjacent end of theshaft and also the projecting hub portion 94 of the impeller, in order to providea shape of hub which will permit of easy entrance of the liquid at the eye of the impeller and at the same time prevent any cavitation pockets around the hub which would produce noise and some loss of efficiency.

There is formed, as an integral part of the closure plate 3, a vertical annular flange 95 which forms the peripheral part of the impeller housin and which contains the throating and to which tubular discharge connections for the throating throats. But since the pressure difference is never more than atmospheric during priming, a slight leakage at this sliding fit is of no moment.

It is to be observed that by removing the cover plate 3 the impeller is completely separated from the bottom and peripheral parts of the housing and the impeller may be readily removed and replaced or renewed, or, in the process of manufacture, any suitable form of impeller may be substituted for the particular form herein shown. Likewise, since the cover plate and impeller housing with throatings are formed integral, the particular form-of housing and throating may be replaced by any desired or known form of housing and throating without alteration of the other parts of the pump. Hence, acombination of various impellers and throatings may be made with a minimum of parts carried in stock.

The impeller housing and throating will now be explained more in detail with reference to Figures 1, 2 and 3.

In the specific housing and throating herein disclosed and illustrated there are two pairs of throats. As viewed in Figure 3, the impeller shaft 9 rotates in a clockwise direction and the throats are tangential discharge throats opening out also in a clockwise direction. The main throats 96 of each pair are anterior to the auxiliary or priming throats 91 of each pair. These'throats are closely adjacent to each other, being separated only by the nose of the wall 99, in each case, between them. A horizontal flange or wall 99 lies substantially at the level of the bottom wall 90, as may be seen in Figures 1 and 2, and this divides the space in the separator into the main space above, the flange 99 and a channel I00, which amounts to a manifold connecting the auxiliary throats 91. The mainthroats 96 communicate freely with the space in the separator 8 above the flange99 and they tend to discharge liquid during priming, which liquid has air admixed therewith, for the removal of air from the intake trap I0 and the connected suction pipe. This mixture of air and liquid has an opportunity to separate, both by the gravity effect and by the centrifugal or dynamic efiect inside the chamber 8, and the denser liquid tends to gravitate downwardly. This horizontal plate or flange 99 is interrupted at the slots I02 and I02 whichprovide relatively free communication between the space in the separator 9 above the flange 99 and are integrally connected as 'by being formed in the channel or manifold I00 below the flange.

The auxiliary or priming throats 91 open downwardly to the channel or manifold I00 through openings which are indicated in dotted lines at I03, I03 in Figure 3. The main throats 96, which open through the peripheral housing or flange 95, communicate through passageways of increased cross-section defined by integral conduit walls I04, as shown in Figure 2, for the main throats, and I05 as shown for the auxiliary priming throats. The main throats and passageways 96 thus discharge tangentially substantially in a horizontal plane, whereas the auxiliary priming throats 91, while they open in a horizontal plane. discharge liquid during liquid pumping helically or downward below the flange lie 99 into communication .with the channel or manifold I00. During priming the openings for or horizontal .baf-

I departing from the present invention.

the periphery of the impeller chamber through the ducts and throats 91 to bev again brought into cooperation with the rotating blade tips to form a further mixture or gaseous fluid which is discharged out at the main throats 96. At low suction the initial mixture of liquid and gas, while more dense than gas, is much less dense than liquid alone. As the suction increases, the return flow through the'priming ducts and throats 91! increases in amount so that a denser medium is formed to produce the necessary discharge pressure to overcome the suction on the inside of the pumping chamber, that is, toward the center of the impeller, and as the suction builds up the medium becomes denser, to the degree .required to produce the necessary discharge pressure, air

being meanwhile discharged in the mixture, separated, and evacuated through the discharge connection 20. When liquid is drawn over in the suction pipe, the density and volume of liquid in the impeller pockets, that is to say, in the blades, is great enough not only tofill the throats 96 but also the throats 91 to provide the necessary or desired discharge of liquid.

It will be apparent to those skilled in the art varied either as to the number of pairs thus coopof throats, a single opening large enough'to provide for both the outflow of mixture and the return of priming liquid, may be provided without Thus, where a single .large throat is employed, the discharge passageways, which are volute-shaped like the extensions of the throats 96 in the present case, may be provided with lateral openings, particularly at the bottom sides of the same as for a vertical pump, 'as in the co-pending application, Serial No. 175,187. In that event, the lateral opening in the volute extension opens preferably downwardly only into the channel I to give substantially the sa'me effect as the downward discharge of the auxiliary throats 91 here disclosed. The shape of the volute in that case is such as to cooperate with a suitable curved blade impeller or any other form of impeller desired. 1

The impeller herein illustrated has substantially straight" blades with backwardly curved tips and with the upstanding wings I conforming to the flared opening I2 in the top plate 2 of the impeller housing. In the present construction, the hub 94 of the impelier 4 is disposed mainly on the bottom side of the median plane of the impeller "itself so that an easy curvature of the hub surface at I0'I leads the liquid from the eye of the plate 2 into the blades without cavitation pockets around the hub. The shaft 6 is keyed to the impeller as shown and the impeller is readily removable from the shaft. ,The shaft is preferably made of a corrosion resisting metal,

the same as the other parts of the pump where the pump is to handle corrosive liquids. While the pump is mainly designed for the handlingof corrosive liquids, it obviously need not be confined to-that service.

The top plate 2 of the impeller housing is secured to the annular wall 25 by means of a flange I08 which is machined to flt with a shrink fit upon a machined annular surface of the bottom rim or margin of the tubular wall 25. To

apply the plate '2 to the tubular wall 25 the same is heated to expand the flange I08 and is thereupon placed in position and shrunk upon the rim of the tubular connection 25. To remove the plate I 08 it may be heated with a blow torch or other suitable means, whereupon it is readily removable, and replaceable. Thus all parts of the pump subject to wear or corrosion are readily serviced or replaced.

The upper end of the impeller shaft 6 is telescopically forced into the lower tubular end of the driving shaft section I09. This shaft section is supported in two ball bearings H0 and H2. The bearing H0 provides radial support and the bearing H2 provides both radial and axial support. The bearing H0 is fastened to the lower end of the driving shaft section I09 and floats in a seat in the sleeve or barrel 5. The upper bearing H2 has its inner ring fastened to the shaft I09-and its outer race or ring is supported upon a supporting flange H3 to sustain the downward load that the number of throats may obviously-be and is clamped by the cover member H4. The flange H3 is carried in a supporting ring H5 and this ring is adjustable vertically with respect to the upper end I I6 of the bracket 5, as by means of the three concealed screws H! (see Figures 7 and 8); These screws are threaded into the supporting member H5 and bear against the top portion I I6 of the bracket 5. The clamping studs or cap screws H8 hold the parts H4 and H5 firmly together and to the bracket 5. Thus by means of the screws H1 and the clamping cap screws H8, the vertical adjustment of the driving shaft I09 and the attached impeller shaft 6 may be made as desired. The lower bearing H0 is preferably provided with a Neoprene ring which acts somewhat like a cup leather, the outer margins of the Neoprene ring I20 being bonded to asheet metal fitting I22 and the inner end of the Neoprene ring I20 being held against the shaft by a garter spring I23. Lubricant is preferably supplied through a duct I24 in the cap I I4 and this supplies the upper bearing H2. The lower hearing I I0 is preferably packed with lubricant and additional lubricant may be supplied through the 'duct I2I.

The operation of the pump, and the constituent parts thereof will be apparent from the foregoing detail description, but I shall recapitulate briefly the operation of the pump as a"whole. The pump is preferably disposed above the source of liquid, a suction pipe is connected to the suction or inlet fitting or neck I1 so that liquid is required to be raised from the source by suction. If it is intended to place the pump below the level of the liquid supply, then a conventional shaft seal is to be employed instead'of the liquid shaft seal herein described, The structure of v the seal may be altered accordingly. The pump is filled to the level of.the filling plug opening- 60, the drain pipe 44 leads back to the source of supply, and any liquid which is wasted by the liquid seal of the shaft is therefore returned to or substantially simultaneously with the dropping of the dischargecpressure-as the liquid on. the intake side of the blades is exhausted, liquid begins to return through the auxiliary throats 91' to form a working fluid the density of which varies with the difierencejn pressure existing upon the discharge and suction sides of the 1m- 1 peller. As the gas or air is gradually evacuated from the suction line and the intake chamber 9,

I0, liquid will be raised in the suction pipe until is is drawn over, whereupon the'pump operates upon liquid, discharging liquid at both the main and auxiliary throats.

During priming the mixture is discharged by the main throats 96 and their tangential volutelike extension above the plate 99 and the gas and liquid separates in the upper part of the separator, the gas escaping at the discharge connection 23. The denser liquid drops into the channel I through the openings I02 in the plate 99 and returns to the periphery of the impeller through the ducts or throats 91. Thus a continuous circulation is carried on so long as priming is required, or so long as the pump does not receive liquid on the intake side. Air is constantly being carried out from the intake side and discharged into the discharge side by the mixing of gas and liquid to form a working fluid, and is discharged into the separator. During this priming operation, liquid is drawn or flows through the inlet duct 56 into the sealing chamber 52, where the liquid entering the passageways into contact with the shaft 6 is caused to be pressed against the shaft at the various inclined vane-like surfaces so as to cre- I uid carried along the surface of the shaft beyond such point and past the constriction between the shaft and the sleeve 48 is thrown clear by the slin'ger 61 into the slinger pocket 66, from which it drains on the outside through the open channel 36 and opening 46 to the return or drain pipe 44 as the case may be;

The swirling of liquid in the separator 8 tends to keep the entry port 62 clear. It will be observed that the return or discharge port 51 from the pocket 52 opens radially inwardly further toward the shaft than does the opening 62 in the supply 'duct 56. Obviously, if desired, the direction of supply. and discharge of liquid through the pocket 52 may be altered and, if desired, the impingement of the swirling liquid upon the supply duct inlet opening may be employed for assisting in the circulation of liquid in and out of the liquid supply pocket 52. In case of stoppage of the pump, particularly before the liquid has been drawn over in the suction pipe, there is a tendency to collapse the vacuum in the suction pipe by very rapid counterflow of liquid out of the pump back into the empty space in the suction pipe. This collapse of the suction 'tends to pull the liquid very rapidly out of the intake trap of the pump because liquid is peculiarly free to be discharged from the separator 6 through all of the throats 91 and 98 in-multiple, and through the large open passageways including the eye I2, the tubular connection It), and the intake passageway I9. Such an occurrence, therefore, tends to clean the pump of liquid in'a few seconds in case of a suction pipe of relatively large capacity and at fairly high suction. The rapidity of counterflow is not so great in the case of a suction pipe fllled with liquid, but even so, it tends to be very rapid. One

'ate, completely around the shaft 6, a plenum of of the difliculties has been to keep the priming charge of liquid in this pump. I have madea special provision to insure the retention of a priming charge when such collapse of the suction occurs on the suction side of the pump.

It will be observed from Figure 1 that the inlet or suction connection I9 communicates, by way of the tubular portion of the trap 25, with the eye I2. The separator space 8 communicates with the interior of the impeller chamber through the volute ducts 96 of the main discharge throats above the flange or baille 99 and communicates by way of the auxiliary or priming throats 91 from below the baflie 99. In the present construction, these four throats give a relatively large and free discharge of liquid from the separator back through the impeller housing, upwardly through the eye thereof, through the tubular portion of the trap 25 and out the inlet connection I9 in case of suction on the inlet pipe being allowed, through cessation of operation ofthe impeller, to pull liquid from the separator through the impeller housing, through the trap As above exsuction and in a fairly large volume of the suction pipe, the collapse of suction in the suction pipe operates with great rapidity to pull the liquid out of the trap through the impeller housing and back toward-the source. The-problem of keeping suflicient liquid in the inlet trap that it may be retained as a priming charge is unusually severe because of the disposition and arrangement of these parts.

In order to insure the retention of a priming charge I have disposed a large part of the trap space at the upper end of the trap and then have divided the trap into two functionally sepa-, rate parts by means of a bafile or wall which is more clearly shown in Figures 5 and 6. This baflle wall I29 defines a downwardextension of the inlet connection I9. Thisdownward extension I32 providesa normal course of inflow for liquid during operation of the pump on liquid and serves as a discharge passageway for liquid when the pump-is stopped and reflow or reflux occurs. At the upper end of the battle or wall I29 "I provide one or more small openings such as I30 shown in Figures 5 and 6, to provide a rement I33 of the trap space communicate freely with each other and with the eye of the impeller housing and with the impeller. "I'hus, normally, in pumping liquid, the suctionpipe will be put under suction and liquid will flow in through the tubular neck I1 defining the inlet passageway I9, down through the passageway I32 and into the eye of the impeller of the pump. Also, liquid will flow over into the storage space I33 and fill the same with liquid. If now, upon stoppa e of rotation of the. impeller; discharge pressure of the impeller upon the throats of the pump drops to less than the suction tending to pull the liquid back, the liquid will begin to flow from the trap back through the throats 96, 91 into the impeller housing, through the eye of the housing, and up through the passageway I32I9.

This backflow does not appreciably deplete the liquid in the storage space I33, since the opening oropenings I30 constitute a very material down to the source.

'ency to remove a part of the priming charge.

space I33 will drop down intothe impeller housing and some 'of it pass over into the separator space 8 and thereby supply the charge of priming liquid for the next start of the pump. Thus the storage space I33, with the major part of its capacity. disposed above the restricted communication, cannot be rapidly emptied and tends to retain sufficient liquid for subsequent operations. If the suction in a partially empty suction pipe at high vacuum is allowed to collapse without filling the pump, there is a tendthat event, the collapse of the suction tends to pull some of the liquid out throughthe passageway" I32 and to pull some of it up into the storage space I33 through the flow, of air or other gas through the opening or openings I30. Sufflcient liquid is thereby diverted into the storage space during the breaking of the seal through the pump that upon dropping of this liquid back into the impeller housing and separator a sufficient charge for repriming is present;

It will be observed that the inlet connection I32 tothe eye l2 of the impeller housing is offset, so that a rapid discharge of liquid through the eye I2 will tend, at least as to the major part, to be directed into the storage space I33.

It is to be understood that this particular feature of liquid retention may be employed or omitted independently of other features of the present pump.- Also it is to be understood that "other means for preventing the outrush of liquid known in the art may be employed without affecting certain other features of the present invention.

I do not intend to be limited to the details of construction herein shown or described except as they are recited as substantial features in the following claims.

I claim:

l. A vertical "self-priming centrifugal pump comprising a hollow body, a central vertical shaft carrying at its lower end an impeller, said body comprising a central intake chamber forming a trap, an impeller housing having an opening facing upwardly into the bottom 'of the trap, and having a peripheral portion provided with throating opening radially outside the intake trap, saidbody containing an annular discharge chamber surrounding the impeller housing and forming a separator, suction and discharge connections opening into the tops of the. aforesaid chambers, respectively,.said intake trap having an enlarged portion at its upper'end to provide a substantial space for trapping priming liquid,

and means fol-preventing emptying of the trap ,upon violent flow of liquid 'out of the suction connection, said means comprising a wall dividing the trapinto two chambers, both chain'- bers opening at their, lower ends into the intake of the impeller housingj 2 m a vertical self-priming centrifugal pump,

a vertical impeller shaft, an impeller at the lower end of the shaft, an impeller housing promeans comprising a wall dividing said intake trap into two functionally separate parts both opening freely into the eye of the impeller and having a restricted communication with each other at their upper ends.

3. A pump body for a vertical pump comprising a hollow casting closed at the top and sides and open at the bottom, there being a top wall with a central depression for a shaft bearing and an aperture for an impellershaft, said casting comprising an outer wall and an inner wall concentric with the shaft opening, walls defining an open gutter leading laterally from said depression for the escape of liquid from the bottom of said depression, the inner wall terminating in an annular rim, and the outer wall terminating at a lower level in an outer annular rim parallel with said inner annular rim.

4. A pumptbody comprising a hollow casting having a closed top wall with a central opening for a shaft in the said top wall, said castingcomprising an outer and .an inner wall' concentric with the central opening, the inner wall terminating in an annular rim, the outer wall terminating in, an annular gasket surface lying below the said rim, said inner wall defining a trap and the space between the inner and outer walls defining a separator, tubular inlet and discharge coiinections' providing external communication wi h ing barrel depending from the top wall and having a bore in line with said opening, said barrel being divided into upper and lower chambers, an integral liquid inlet duct extending from the separator through the inner wall to the lower chamber in the barrel, and a liquid drain duct leading from said upper chamber through said inner and outer walls for draining oil escaping liquid from said seal. Y

5. A pump body comprising a hollow castin closed at the top and sides and open at the bottom, there being a top wall with a central de-' pression for a shaft bearing and an aperture for an impeller shaft, said casting comprising an outer substantially cylindrical wall and an inner substantially cylindrical wall concentric with the shaft opening and separated by an-annular separating space, the inner wall terminating in a free annular rim and the outer wall terminating at a lower level in an outer annular rim parallel with said inner annular rim, and a mounting flange integral with said casting at the upper end of thegicentral depression for supporting a bearing in said depression.

6. The combination of the pump body of claim 3 having a depending liquid seal barrel extending below the depression and having a bore in line with said opening, an integral duct extending from the lower end of the bore to the space between said concentric walls and an integral duct extending from the upper end of the said bore to the outside of the pump body, said last named duct lyingbelow said open gutter and having an opening communication with said gutter at its outer end,- and a common drain for draining liquid from the gutter and the adjacent duct.

7. In a vertical pump. a shaft bearing and sealing structure comprising a cup-shaped depression the trap and separator, respectively, a sealin the top wall of a pump body,said depression having a clamping flange about its upper margin, a bearing sleeve piloted into the upper end of said depression and having a clamping flange to clamp the sleeve in position with respect tothe first clamping flange, a shaft section disposed in the sleeve, bearings for radial and for thrust load disposed between the shaft section and the bearing sleeve, an impeller shaft joined to the shaft section, a, liquid sealing barrel depending from the walls of the cup-shaped depression, a liquid sealing sleeve embracing the shaft and disposed in the sealing barrel, a drain externally for the cup-shaped depression, and a, drain duct leading from the inside of the upper end of the sealing sleeve to the outside of the pump the inner end of thesealing sleeve being exposed to the suction side of the impeller.

8. A pump housing for a vertical self-priming pump, comprisin a top plate having a central inlet opening and a circular periphery and a main body portion comprising a bottom plate and a vertically extending peripheral flange telescopically embracing the periphery of the top plate, said peripheral flange having hollow tangential extensions defining pairs of throats and substantially horizontally extending bafiies disposed between the outlets of the throats of each pair, and an extension of the bottom plate serving to define an annular passageway below said bafile, said annular. passageway constituting in efiect a manifold connected to one of the throats of each pair.

9. A pump body comprising a hollow casting having a closed'top wall with a central opening for a shaft in the said top wall, saidcasting comprising an outer and an inner wall concentric with the central opening, the inner wall terminating in an annular rim, the outer wall termimating in an annular gasket surface lying below the said rim. said inner wall defining a trap and the space 'between the inner and outer walls defining a, separator, tubular inlet and discharge connections providing external communication with the trap and separator, respectively; and a substantially vertical partition in said trap for constituting the space within the trap as two separate portions, the smaller portion forming a continuation of the inlet connection, and the larger portion forming a liquid storage space, said portions communicating with each other through a restricted openin in the top of said dividing wall and communicating freely with each other below. the bottom of said wall.

10. In a pump, the combination of a tubular member defining an inlet passage, said member terminating in an annular rim, and an impeller housing part comprising a centrally apertured side plate member lying against the end of said rim and having a short circular flange thermally shrunk upon and tightly embracing the periphery of said rim for supporting said housing part upon sa d rim.

11. A main body for a vertical self-priming centrifugal pump consisting of a hollow integral casting closed at the top and open at the bottom comprising two substantially cylindrical walls having substantially a common vertical axis and terminating as free annular rims in spaced horizontal planes with the outer wall extending a substantial distance below the inner wall, a top wall having an open central depression surrounded by a bearing mounting flange, and an integral shaft seal sleeve disposed within the inner wall and extending to a point adjacent the lower end of said inner wall.

12. An integral pump body for a vertical selfpriming pump comprising a series of coaxial substantially vertical annular walls comprising a central sleeve for sealin a vertical shaft, the upper end of the sleeve being enlarged to define a bearing pocket, an intake trap Wall surrounding the sleeve and having an intake connection opening into the top of the trap, a separator wall surrounding the intake trap wall and defining an annular separator chamber; a discharge connection opening into the top of the separator chamber, and joinin walls between the sleeve and the upper ends of the trap and separator walls.

13. In a vertical self-priming pump, a hollow body casting comprising a top wall, a vertical annular separator wall joined to the top wall and open at the bottom and having a clamping flange about the margin of the open end, a central wall defining a sealing sleeve open at both ends, said sleeve being connected to the top wall, a liquid supply tube within the hollow body leading from a point adjacent the separator wall to the inside of the lower end of the sleeve, and a liquid drain tube leading from the upper end of the sleeve and extending through the separator wall and opening outside of said separator wall.

14. In a vertical self-priming pump, a hollow body casting comprising a top wall with a central opening, a vertical annular separator wall joined to the top wall and open at the bottom and having a clamping flange about the margin of the open end, an annular pocket defining wall joined to the margins about the opening in the top wall and extending above the top wall, and having a bearing supporting flange at its upper end, a sealing sleeve open at both ends joined at its upper end to the lower end of said pocket defining wall, an intermediate annular wall surrounding the sleeve and defining a trap, a supply tube within the body extending from a point adjacent the separator wall through the intermediate wall and opening into the lower end of the sleeve, a drain tube extending from the upper end of the sleeve through the intermediate wall and through the separator wall and carrying a pipe connection outside the body.

15. The pump body of claim 14 wherein a depressed groove is formed in the-top wall, separator all and intermediate wall, and disposed over said drain tube to provide an open drain from the bottom of the pocket, and a drain eonduit communicating with said open drain and with said drain tube.

16. In a pump the combination with an intake conduit having a tubular portion with an external peripheral seat at'its end, and an annular impeller housing plate having an aperture at its center and provided with a flange adapted to embrace said peripheral seat, said plate having its flange thermally shrunk upon and gripping said peripheral seat, and means for keeping said joint submerged in liquid.

vl7. In combination in an acid resisting pump, a tubular conduit of cast acid resisting metal terminating in a plane substantially at right angles to the longitudinal axis of the conduit and having a circular external peripheral seat and a cast acid resisting metal plate provided with a short integral flange embracing said seat and gripping the same by thermal contraction.

18. In a self-priming centrifugal pump, an integral hollow pump body comprising a top wall having a central depression forming a bearing pocket and a sealing sleeve extending down from the bottom of the pocket, an outer substantially cylindrical wall joined to the top wall and terextension of the lower end of the walls of said pocket, the walls of the pocket terminating above tegral hollow pump body comprising a top wall havinga central depression forming a bearing pocket and a sealing sleeve extending down from the bottom of the pocket, an outer substantially cylindrical wall joined to the top wall and terminating at its lower end in a clamping flange, an

inner substantially cylindrical wall substantially concentric with said outer wall and terminating at its lower end a substantial distance above the clamping flange, the upper end of the inner wall flaring out and joining theouter wall at a level a substantial distance below ,the Junction of the top wall and the outer wall, and a depression in the top and side walls forming an open drain groove extending from the bottom of the, pocket,

said sleeve having a liquid supply pocket adjacent its lower end and a liquid drain pocket adjacent its junction with the bottom of said bearing pocket, a liquid supply duct extending from a point between the lower ends of said cylindrical walls to said supply pocket, and a liquid drain duct extending from said drain pocket to the out-' side of the body, said drain duct lying immediately beneath said groove and having awall common with the bottom of'the groove.

20. A vertical self-priming centrifugal pump comprising a hollow body casting having a top wall, a substantially cylindrical outer wall joined to the top wall and terminating at itslower end in a clamping flange, said top wall having a central depression, an open seal sleeve forming an the top wall in a clamping flange, a bearing barrel extending down into said pocket and projecting above the top of the pocket, a mounting flange intermediate the ends of the bearing barrel, said mounting flange being removably clamped to the clampin flange, a vertical shaft extending through said bearing barrel and sealing sleeve and carrying. an impeller at its lower end, said impeller being removable through the open bottom of said body, and hearings in said bearing sleeve for supporting the vertical shaft axially and radially.

21. In a vertical self-priming pump the combination of a main hollow body closed at the top and open at the bottom comprising a top wall, a depending outer cylindrical wall and an inner cylindrical wall terminating above the lower end of the outer wall, a two part impeller chamber of the concentric type comprising an apertured top plate mounted on the lower end of the inner wall, a cooperating housing portion having an extending flange seating against the lower end or the outer wall to provide a closure for the body, said housing portion having peripheral throating comprising pairs of throats and an interrupted horizontal annular flange separating the throats of each pair from each other and defining a common annular communicating passageway in the bottom of the pump body for. corresponding peripheral sealing face, an impeller housing side plate comprising a disc-like body with a central opening and having a flat annular wall and a short integral cylindrical wall forming an annular flange about the periphery of the flat annular wall, said flange being thermally shrunk upon said Peripheral sealing face and being releasable by heat applied to said flat annular wall.

HARRY E. LA BOUR.

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