US3063377A

US3063377A - Centrifugal jet pump

Info

Publication number: US3063377A
Application number: US784316A
Authority: US
Inventors: Peter J Stanley; Lee S Tillery
Original assignee: CLAYTON MARK AND CO
Current assignee: CLAYTON MARK AND CO
Priority date: 1958-12-31
Filing date: 1958-12-31
Publication date: 1962-11-13
Anticipated expiration: 1979-11-13

Description

Nov. 13, 1962 P. J. STANLEY ETAL CENTRIFUGAL JET PUMP 2 Sheets-Sheet 1 fif z l Mw Filed D80- 51, 1958 Nov. 13, 1962 P. J. STANLEY ETAL 3,063,377

CENTRIFUGAL JET PUMP 2 Sheets-Sheet 2 Filed D60. 51, 1958 WM H I Ofe d Z6 K614. FMMW 5% Unite States Patent 3,063,377 CENTRIFUGAL JET PUMP I Peter J. Stanley, Evanston, and Lee S. Tiller-y, Morton The present invention relates to centrifugal jet pumps and has for its primary object the provision of a new and improved centrifugal jet pump of a type convertible for use for wells of different depths such as shallow, intermediate depth and deep wells. More particularly, it has for its object the provision of a new and improved self priming centrifugal jet pump. v

The pump of the present invention is primarily intended to be used in a water supply system. It may be used for shallow wells up to about 25 feet and for wells of intermediate depths up to 40 feet and for deep wells up to about 80 feet or somewhat more. A single .jet assembly is used for both the shallow and intermediate depth wells.

For the shallow wells the jet assembly is attached to the pump itself. For the intermediate depth wells the jet assembly is detached from the pump and placed in the well. For the deep wells a different jet assembly is utilized in the well.

In the pumps of the foregoing type, ditficulties have been encountered in priming, especially when the pump is used as a shallow well pump and operated at open discharge. This type of operation is encountered as when the pump is used to supply water as to a cattle drinking trough or in most installations in testing prior. to connection of the pump to a supply tank. In starting operation, the pump is given an initial charge of water which consists in filling the pump housing'and downpipe, provided the check valve is placed at the bottom of the well where it is preferably placed. However, in many cases, this initial charge is not sufiicient tomake the pump thereafter a self-priming pump. In many installations the pump has to be filled each time that the pump is placed in operation and this is particularly true withpumps operated on open discharge. The object of the present invention is to provide in simple manner a self-priming pump, i.e. a pump which will operate without requiring subsequent manual priming after the pump has initially been filled or charged with priming liquid.

Accordingly, it is an object of the present invention to provide a self-priming centrifugal jet pump which can be made economically with a minimum of material and in which the priming is supplied by a simple device consisting of a tube communicating with the inlet of the centrifugal pump and supplying water to that inlet from near the bottom of the pump discharge housing.

In brief, the centrifugal jet fluid pump of the present invention includes a discharge housing comprising generally pear-shaped parallel end walls and a side Wall connecting the end walls. One of the end walls is provided with a circular opening at the bulbous region of the housing. The other of the end walls is provided with a pair of smaller opening of which a first is coaxial with the circular opening and a second is located below the first and near the lower end of the housing. Centrifugal pumping means is disposed in the housing. This pumping means includes a motor driven impeller rotated about a substantially horizontal axis and an impeller surrounding volute mounted at the circular opening of the said one end wall. The volute has a pair of peripheral discharge opcn- Patented Nov. 13., 1962 ings located generally in a horizontal plane passing through the axis of the impeller. One of the discharge openings faces downwardly and the other upwardly. The volute is provided with a coaxial opening defined by an axial extension and the impeller has a coaxial inlet disposed within the volute opening. Means are provided to minimize or prevent the passage of water between the impellcr inlet and the volute opening. The second end Wall 'of the housing has an inwardly extending generally cylindrical portion coaxial with the volute opening and of substantially the same size. This inwardly extending portion is connected in sealed manner with the volute axial extension; A venturi tube is mounted within the first of the "two wall openings and it is arranged to discharge into the impeller inlet. A nozzle is provided to discharge into the venturi tube and the nozzle is connected to the second opening in the other end wall of the housing, whereby the nozzle is supplied with water under pressure discharged by the centrifugal pump. The self-priming of the present invention is provided by a conduit called a priming tube and located within the pump discharge housing. It has one end connected to discharge into the region between the venturi tube and the impeller inlet, this being at the uppermost part of the inlet substantially at a location ,which may be conveniently described as the 12 oclock region. The other end of the tube, i.e. the inlet end thereof, is located near the bottom of the discharge housing at the region approximately half-Way between the vertical center line of the impeller axis and the vertical plane of the said one volute opening, where there is substantially no'air entrained in the water. The housing is of a size that it has a larger capacity than that of the impeller and-its associated. volute. Itscapacity is such that after the housing is initially charged with water preparatory to operation and the pump is started, there is an initial starting surge in which some of the water is discharged after which the impeller remains substantially covered with water." The construction and operation is thus such that after the initial charging and starting of the pump there remains enough water in the pump that it is recirculated through the jet. At the same time, water is supplied by the priming tube from a quiescent region of water at the bottom of the discharge housing to the impeller inlet or eye. The pump has a discharge outlet at the upper side of the discharge housing and an inlet connected to a point between the nozzle and the venturi. The inlet is connected, for shallow well operation, to the well downpipe. The construction and arrangement are such that selfpriming of the pump occurs. The impeller forces water to the discharge chamber. Some of this water is supplied to jet and some to the priming tube. As a result, air and Water are removed from the downpipe. The air escapes from the discharge opening and the water is recirculated until the pump operates as a fully primed centrifugal jet pump. The pump becomes fully operative in a relatively short period of time such as between two to five minutes depending upon other circumstances. The pump is not only self-priming when connected to a conventional water supply system including a pressure tank but when the pump operates on open discharge. Also after having been placed in operation as described above, it reprimes itself should this become necessary for any reason such as a leak in the downpipe or major changes in water level in the well.

Otherobjects and advantages of the present invention will become apparent from the ensuing description of an illustrative embodiment of the invention, in the course of which reference is had to the accompanying drawings, in which:

FIGURE 1 is an end elevational view of the pump of the invention;

FIGURE 2 is an enlarged vertical axial cross-sectional View taken along the angular line 22 of FIGURE 3 and illustrating fragmentarily and partly in section the motor for driving the pump;

FIGURE 3 is a fragmentary vertical diametrical crosssectional view of the pump taken along the line 33 of FIGURE 2; and,

FIGURE 4 is a view similar to FIGURE 3 taken along the line 4-4 of FIGURE 2.

Referring now to the drawings, and first primarily to FIGURES 1 and 2, the pump of the present invention is illustrated as a whole by the reference character 10. As clearly illustrated in FIGURE 2, it is shown to be of the centrifugal jet type, and it is adapted to be driven by a motor shown but fragmentarily and indicated by the reference character 12. The motor is of known type including a housing 14 having an end bell 15 and a driven shaft 16 generally rotated at a speed of about 3450 to 3600 r.p.m. and sealed by a rotary seal (not shown). The size of the motor varies depending on the capacity of the pump. For example, it may be of =1, V2 or Vs horsepower.

The pump 10 of the invention includes a discharge housing indicated as a Whole by the reference character 20 within which is a discharge chamber 22. Upon reference to FIGURE 1, it may be seen that the housing is of a shape that can be described aptly as substantially pear-shaped. It includes a rather bulbous lower portion 24 and a generally triangular or trapezoidal upper portion 26. The housing may be made in various ways but as illustrated it is made as a single casting with a pair of generally pear-shaped

parallel end walls

28 and 30, the former of which for convenience will be described as the front wall and the latter as the rear wall. These two walls are interconnected by a continuous side wall 32.

In addition to the housing 20, the main parts of the pump are a motor driven impeller 34 and a surrounding volute 36, a venturi 38, a nozzle discharging into the venturi and the priming means 42 of the present invention which is shown as a tube 44, which can be made of brass, copper or plastic, or it may be made as an integral part of the volute.

The impeller 34 is of known constitution. It includes a central hub 46 attached to the end of the motor shaft 16. an imperforate front plate 50, between which are located a plurality, such as six, outwardly divergent radial discharge passageways 52. At the axial region the discharge passageways 52 communicate with an impeller inlet 56 or eye, as it is sometimes called, defined by a cylindrical axially extending portion 54 of the impeller.

The volute 36 surrounds the impeller and together with a portion of the motor end bell 15 provides an impeller chamber 58 enclosed at its front by the cover portion 60 of the volute which has an axial forwardly extending extension 62 surrounding the impeller inlet 56. Leakage of water between the impeller inlet and volute may be minimized by close dimensioned clearance or prevented as by a gasket 64 disposed between

flanges

54 and 62. The volute is provided with a pair of peripherally extending tapered discharge passageways and 72, see FIGURE 3, of which the former faces downwardly and the latter upwardly. The discharge openings are arranged to be in a generally horizontal plane and the impeller rotates in a direction corresponding with the direction of enlargement of the discharge passageways and as indicated by the arrow 74 in FIGURE 3.

The volute is relatively small in size in comparison with the pump housing and discharge chamber. It extends only a short distance axially of the chamber 22 It includes also an imperforate rear plate 48 and 4 and is located substantially within the bulbous part 24 of the pump housing.

The volute 36 is held in place by the pump housing 20, the latter being provided with a generally tubular inwardly extending portion 76 coaxial with the volute extension 62 and engaging the latter with considerable force through a sealing gasket 78, see FIGURE 2. The housing 20 in turn is secured to the motor end bell as by the plurality of bolts 80 and both it and the volute engage a sealing gasket 81. The volute is located relative to the pump housing by a locating tongue 82 on the volute and a slot 84 receiving the tongue in the end wall 30 of the housing, see FIGURES 2 and 3.

The venturi 38 and nozzle 40 are mounted in what is commonly termed a jet body detachably secured as by the bolts 91 to the front wall 28 of the pump housing. The latter is provided with a first opening 92 located coaxially relative to the impeller inlet. The opening 92 includes an outer threaded portion 94 and an unthreaded inner portion 96 adjacent the axial extension 76. The end wall 28 also includes a second internally threaded opening 98 below the first opening 94 and which opening communicates with the lower part of the pump discharge chamber 22.

The venturi 38 is secured as by a threaded connection 100 to the jet body 90 so as to be generally coaxial relative to the impeller inlet 56 and so that it discharges into the impeller inlet. The jet 40 is mounted upon an internal partition 102104 defining a passageway 106 having an opening 106A connecting the nozzle with passageway 98. The inlet of the venturi is connected by a passageway 108 to a threaded opening 109 forming the inlet of the pump and connected in shallow well service to a drop pipe 110 extending down into the well.

In accordance with conventional practice, the impeller inlet is adapted to be connected to suitable air charging apparatus, not shown, through a passageway 112 communicating with the inlet of the pump through an annular passageway 114 provided by the space between the discharge end of the venturi tube and the opening 96 in the iznswardly projecting extension 76 of the pump front wall The pump is made self-priming in accordance with the present invention by priming means 42 comprising the tube 44. Referring now to FIGURES 2 and 3, it will be noted that the inlet end of the tube is disposed near the bottom of the discharge chamber 22 and at a region between a vertical plane passing through the axis of the impeller and a vertical plane passing through the volute discharge passageway 70. It has been found that the location of the tube is somewhat critical and the indicated location is preferable because the water in the discharge chamber is most air free at this region. The inlet end of the tube 44 is fixedly located as by passing it through an apertured lug 122 formed integrally with the volute 36.

The discharge end of the priming tube is indicated by the reference character 124 and its location is such that it is approximately at what might be called the 12 oclock region of the impeller inlet. This end of the tube is held in non projecting manner in opening 126 in the axial extension 62 of the volute, the tube thus being made to discharge into the space 128 between the impeller inlet and discharge end of the venturi. Best results have been obtained by locating the discharge end of the priming tube rather close to the 12 oclock region of the impeller inlet. However, some latitude is permissible in its location. For example, it may be located in a region described as 11 to 1 oclock although some advantage can be obtained if located in a wider region from 10 to 2 oclock. However, best results are obtained, as already indicated, when the discharge end is quite close to the 12 oclock region. Just why this should be the case is not definitely known at the present time although it may be that the introduction of substantially air free water at this region insures filling of the impeller eye with water, thereby making the pump operate effectively to remove air from the pump and downpipe. r

Generally, a pump of the character-described is suplied with a separate check valve (not shown) at its inlet end. This check valve may be located close to the jet body 90, but preferably it is located below the water level in the well, at which location it is commonly termed afoot valve. v The discharge from the ressure chamber is located at the top of the chamber at which point there is a threaded outlet opening 130 to which a discharge pipe 132 is connected. In open discharge, the pipe 132 discharges to atmosphere. In most installation, however, the pipe 132 leads to a pressure tank, notshown, and constituting part of a system in which the water is maintained at a pressure between 20 to 40 pounds. Whenever the pressure drops below the desired minimum, the motor is placed into operation as by a pressure switch means indicated by reference character 134 in FIGURE 1 and which has a connection 136 leading to the discharge chamber 22.

As heretofore indicated, the greatest difiiculty in proper priming of prior pumps is encountered in shallow well operation with open discharge operations, i.e. when the discharge of the pump is connected to atmosphere and pipe 110 is used as a suction pipe extending below the water level in the well. The difliculty in priming results from the fact that when pump is placed into operation there is an initial surge of discharge which empties the pump to a considerable extent so that the pump loses its prime. In the present construction, this does not occur.

To place the pump in operation the discharge chamber 22 is filled or charged with water. Generally this means that not only is the discharge chamber 22 filled with Water, but the impeller and volute are filled and so are the jet body and the inlet pipe 110 down to the check or foot valve, whichever may be the case. Then when the pump is placed in operation there is an initial surge of water from the discharge, however, the present apparatus is so constructed and arranged, as mentioned, that this discharge does not empty the chamber but rather the impeller and volute remain substantially covered with water. Approximately seventy percent of the initial filling of water remains in the pump. At the same time, water from the quiescent bottom region of the discharge chamber is supplied to the impeller inlet thereby to maintain the impeller in effective operation as a result of recirculation of the priming liquid. The pump thus operates effectively to draw water and air from the downpipe until all the air escapes through the discharge opening and the pump becomes fully primed.

Thus far the description of the pump has been with the pump adapted for shallow well operation. To convert it to an intermediate depth well, the jet body 90 is removed and connectedto a pair of pipes and placed in the well below the normal water level. When this is done, the opening 106A in the jet body is connected by a first pipe to the opening 98 and an opening 140 in the jet body is connected by a second pipe to the opening 92. In this type of operation, priming is carried on in the same way as heretofore described with water from the quiescent bottom region of the discharge chamber 22 being supplied to the impeller inlet through the priming tube 44.

To convert the pump to a deep well pump, the connections are as in the intermediate depth described above, except a different jet and nozzle are used. Priming is carried on the same as heretofore.

While the present invention has been described in connection with details of a particular embodiment thereof, it should be understood that these details are not intended to be limitative of the invention except insofar as set forth in the accompanying claims.

' What is claimed as new anddesired to be secured by United States Letters Patent is as follows:

1. A centrifugal jet fluid pump including in combination, a discharge housing having a bulbous region and formed of generally pear-shaped, parallel end walls and a side wall connecting the end walls, one of said end walls having a circular opening at the bulbous region of the housing, the other of said end walls having smaller first and second openings of which the first is coaxial with the circular opening and the second is located below the first and near the lower end of the'housing, centrifugal pumping means includinga'rotatable impeller and a surrounding volute mounted in the circular opening of said one end wall, said volute having a pair of peripheral divergent discharge openings located. generally in a horizontal plane passing through the axis of the impeller, said impeller rotating in the direction of divergence of said openings, one of said openings facing downwardly and the other upwardly, said volute having a coaxial inlet defined by an axial extension and the impeller having a coaxial inlet disposed within said volute inlet, a seal between said inlet and volute opening, said second end wall having an inwardly extending generally cylindrical portion coaxial with the volute opening and of substantially the same size, sealing means connected between said portion and the volute axial extension, a venturi tube mounted in the first wall opening and discharging into the impeller inlet, a nozzle mounted to discharge into the venturi tube and in fluid communication with the second opening in said other end wall, and a priming tube Within said discharge chamber having one end connected to dis charge between the venturi tube and impeller inlet at the uppermost region thereof and having its other end near the bottom of the discharge housing at a region approximately halfway between the vertical center line of the impeller axis and the vertical plane of the said one volute opening wherein the fluid is substantially free of air and said housing being larger than the capacity of the impeller and volute and so that after the housing is filled with water the impeller remains covered with water after the initial starting discharge surge.

2. A centrifugal jet fluid pump including in combination, a discharge housing having a bulbous-region and formed of generally pear-shaped, parallel end walls and a side wall connecting the end walls, one of said end walls having a circular opening at the bulbous region of the housing, the other of said end walls having smaller first and second openings of which the first is coaxial with the circular opening and the second is located below the first and near the lower end of the housing, centrifugal pumping means including a rotatable impeller and a surrounding volute mounted in the circular opening of said one end wall, said volute having a pair of peripheral divergent discharge openings located generally in a horizontal plane passing through the axis of the impeller, said impeller rotating in the direction of divergence of said openings, one of said openings facing downwardly and the other upwardly, said volute having a coaxial inlet defined by an axial extension and the impeller having a coaxial inlet disposed within said volute inlet, said second end wall having an inwardly extending generally cylindrical portion coaxial with the volute opening and of substantially the same size, a venturi tube mounted in the first wall opening and discharging into the impeller inlet, a nozzle mounted to discharge into the venturi tube and infiuid communication with the second opening in said other end wall, and a priming tube within said discharge chamber having one end connected to discharge between the venturi tube and impeller inlet at the upper most region thereof and having its other end near the bottom of the discharge housing at a region approximately halfway between the vertical center line of the impeller axis and the vertical plane of the said one volute opening wherein the fluid is substantially free of air, and said housing being larger than the capacity of the impeller and volute and so that after the housing is filled with 'water the impeller remains covered with water after the initial starting discharge surge.

References Cited in the tile of this patent UNITED STATES PATENTS Ferguson July 1, 1941 Rupp June 23, 1942 Adams Dec. 29, 1942 Stepanoff Mar. 7, 1944 Mann May 8, 1945 France Feb. 6, 1957