US2694365A

US2694365A - Deep well self-priming system and pump unit therefor

Info

Publication number: US2694365A
Application number: US287370A
Authority: US
Inventors: John E Armstrong; Jacuzzi Candido
Original assignee: Jacuzzi Brothers Inc
Current assignee: Jacuzzi Brothers Inc
Priority date: 1952-05-12
Filing date: 1952-05-12
Publication date: 1954-11-16
Anticipated expiration: 1971-11-16

Description

Nov. 16, 1954 .1. E. ARMSTRONG E'rAx. 2,694,365

DEEP WELL SELF-PR'IMING SYSTEM AND PUMP UNIT THEREFOR Filed May 12, 1952 6 Sheets-Sheet l INVENTORS JOHN E. ARMS TRU/V6 BY GND/DO JAQUZZ/ @ma M THE/ TTRNEYS Nov. 16, 1954 J. E. ARMSTRONG Erm. 2,694,365

DEEP WELL SELF-PRIMING SYSTEM AND PUMP UNIT THEREFOR Filed May l2, 1952 6 Sheets-Sheet 2 5l-z' a mlm/roles JOHN E. ARMSTRONG BY CANDIDO JA GUZZI THE/Ii A TTORNEYS N0V 16. 1954 J. E. ARMSTRONG Erm. 2,694,365

DEEP WELL SELF-PRIMING SYSTEM AND PUMP UNIT THEREFOR Filed may 12, 1952 6 Shets-sh'feet s #www 'I |@lI n l I fg f7 1 r l lz! JOHN E. ARMSTRONG BYCANDIDO JAOUZZ/ m THE/l? A TTORNEYS Nov. 16, 1954 J. E. ARMSTRONG Erm. 2,694,365

DEEP WELL SELP-PRIMING SYSTEM AND PUMP UNIT THEREFQR Filed May 12. 1952 6 Sheets-Sheet 4 INVENTORS JOHN E. ARMS THONG BY CANDIDO JACUZZI @Muffy/M1159 THE Il? A TTORNEYS NOV 16, 1954 J. E. ARMSTRONG ETAL 2,594,365

DEEP WELL SELF-PRIMING SYSTEM AND PUMP UNIT THEREFOR Filed May 12, 1952 6 Sheets-Sheet 5 JOHN E. A BY CANDIDO JACUZZ/ m )L THE/? ATTRNEYS Nov. 16, 1954 J. E. ARMSTRONG r-:rAL 2,694,365

DEEP WELL SELF-PRIMING SYSTEM AND PUMP UNIT THEREFOR Filed May l2, 1952 6 Sheets-Sheet 6 H/S ATTORNEYS WELL SELF-FRIMENG. SYSTEM AND PUR/ll UNET THEREFGR E. Armstrong, Richmond, and Candido iacuzzi, Lafayette, Calif., assignnrs to .lacuzzi Bros., Incorporated, a corporation of California Appiication l2, 1952, Serial No. Ztl

ld Claims. (Cl. 3103-5) Our invention relates to pump systems, and more particularly to a deep well self-priming system and pump unit assembly therefor.

Among the objects of our invention are- (l) To provide a novel and improved pump system.

(2) To provide a novel and improved pressure system of the type including a pressure tank.

(3) To provide a novel and improved deep well selfpriming system requiring no valves below ground level, nor conventional control valves on the discharge side of the system.

(4) To provide a novel and improved deep well pressure system with an included self-priming feature.

(5) To provide a novel and improved pump unit assembly.

(6) To provide a novel and improved pump unit assembly for use in a deep well system.

(7) To provide a novel and improved pump unit assembly capable of being converted for incorporation into different pump system arrangements.

(8) To provide a novel and improved pump unit assembly of compact construction.

Additional objects of our invention will be brought out in the following disclosure of the same in its preferred form as illustrated in the accompanying drawings wherein- Figure l is an elevational view of a pressure system installation embodying the present invention;

Figure 2 is a view in section through the pump unit assembly of Figure l;

Figure 3 is a view in section through the pump unit assembly of Figure l taken in substantially the planes 3 3 of Figure 4;

Figure 3a is a View in section of a fragmentary portion of the pump unit of Figure 3.

Figure 4 is a view in section through the pump unit assembly of the system of Figure l, taken in the plane Figure 5 is a view in section through the pump unit assembly portion of the system taken in the plane 5-5 of Figure 1;

Figure 6 is a View in section through the pump unit assembly of the system of Figure l, taken in the plane Figure 7 is a view depicting a moditication of the system of Figure l;

Figure 8 is a fragmentary View depicting a modification of the system of Figure 7.

Figure 9 is a view iii section depicting another ernbodiment of the present invention.

Referring to the drawings for a description o f the present invention, the pump unit assembly 'il which is the heart of the system combination illustrated, comprises in general a plurality of groups of impeller stages mounted Within a common casing having formed therein various passages and chambers enabling the impeller groups to be connected in various system arrangements with external system components through the simple expedience of closing, opening or interconnecting passages provided for such purposes.

More specifically, the preferred pump unit assembly illustrated, comprises a base section 3 including the rst stage 5, a plurality of additional stages .7, 9,. 1l, etc., superimposed thereon, all such stages being divided by a partition 15 to form a first group of stages below the partition and a second group of stages above the part1 tion. Above the impeller stages is mounted a pump died tats tritt motor supporting bracket 17 which has aflixed thereto and carries, the motor 19 for driving the impellers.

The base section 3 comprises a casting having a floor 21 in the center of which is located a bearing 23 for supporting the lower end of a pump shaft 25 on which the impeller components are mounted and keyed. Surrounding the bearing is an oifset circular wall 27, defining a chamber 29 leading to the lowermost stage of the pump unit assembly.

Such wall is connected by radial partition walls 31 to the outer wall 33 of the base section, and is joined to said outer wall by a dished joining wall 35, providing a central recessed chamber for the impeller 37 of the tirst stage, and at the same time forming with the partitions 31, a plurality of

arcuate chambers

39, 41, 43, three in number in the specic embodiment illustrated.y Each such chamber is exposed upwardly through an arcuate opening 45 in the joining wall, such openings being located within 270 degrees of arc, thus leaving approxlilrnately 90 degrees of blank space 47 in the joining wa Superposed on the base section is a stage casing 49y providing a recessed chamber for a second stage inipeller 51, and having integrally formed vanes 53 for guiding the output of the first impeller to the input of the second, and additional varies 55 distributed about its upper surface to constitute guides for the discharge from such stage to a subsequent portion of the pump unit.`

a stationary partition 15 having a rotary seal 61 about' the pump shaft, and like the stage section, is cast with wall passages 63 in alignment with those in the stage section below.

Above the partition is assembled a pair of impeller stages 9, 11 similar in design to that of the second stage previously described, and wall passages 69 in alignment with those below; and completing the last stage, is a stage casing 71 having wall passages 73 in alignment with those previously mentioned. The aligned stage wall passages thus form a plurality of pump wall passages 75, 77, 79, 81, each such passage terminating at the upper end of the stages, in exposed openings.

Mounted on the last stage section, mentioned pump motor mounting bracket 17, said bracket having a rotary seal 83 in the floor thereof through which the pump shaft passes for coupling to the shaft of the drive motor.

When so mounted, the bracket forms with the topmost stage section, a chamber S5 in direct communication with the pump wall passage 79 (Figure 2), the ioor of the bracket serving at the Sametime to block off the upper end of the passage '77 (Figure 3). At the point where the chamber 85 empties into the passage 79, we install a normally closed air inlet valve 86 preferably of the snifter type.

The remaining two pump Wall passages 75 and 81 are connected together through a gooseneck 87 formed in the racket casting and integral therewith, such gooseneck providing a connecting passage extending from the wall passage 'ed up and over a dividing Wall 259 to make connection with the remaining pump wall passage 75. Any

air inlet valve 99, similar to the valve 86, is mounted in the wall of the gooseneck.

The pump unit casing formed by the assembling of the base, the various stage sections and the motor bracket, will thus include four vertical Wall passages, i

through the partition to the input of the thirdstage, its lower end blocked 01T,

while the passage S1 which has like the second stage, having is the previously` The remaining two passages has a ow connection from the output of the second stage, provided by a channel 93 likewise formed in the partition.

To effect operating connections from the pump unit to external components of the pump system, pipe connection openings are provided to the various chambers in the base section, said chambers in turn being ow connected to the various passages in the pump unit casing as previously indicated. Thus, one such opening 95 is provided in the wall of the base section exposing the chamber 39 at the lower end of the through passage connecting with the gooseneck. Another such opening 97, preferably of larger diameter, is provided to expose the adjacent chamber 41 connecting with the passage which leads to the third stage of the pump unit.

An external connection with the passage 79 leading down from the output of the last stage to the base charnber 43, is made through a third opening 98 in the base casting, at which point in the base casting, is provided a pipe fitting 99.

Concentrically with such latter opening, a threaded opening of smaller diameter is formed in the circular wall 27 within the base section, thus providing for the bringing out of

concentric pipes

101, 103 from the base section of the pump unit, in the preferred embodiment of the same.

With the pump unit thusly arranged, water entering the input to the first stage will be discharged from the second stage into the pump wall passage 81, which being closed at its lower end, said water will pass upward therein and by way of the gooseneck into the associated through passage 75 where it may emerge from the pump casing by way of the opening 95 from the chamber 39 at the lower end thereof.

Water entering the casing through the adjacent and larger opening 97 will flow into passage 77, which being blocked at its upper end, the water will be guided by the partition to the input to stage three, from which it will pass through the succeeding mpeller stages, down through passage 79 and out of the casing through the larger of the concentric pipes 101.

The pump unit assembly described above lends itself to incorporation into a pressure system embodying many novel features, a preferred embodiment of such being illustrated in the drawings. Such system is a deep well self-priming pressure system requiring absolutely no moving parts down in the well, in addition to possessing the feature of operating without the need of a control valve.

ln this system, we provide a tank 105 somewhat along the lines of that illustrated and described in our Patent No. 2,486,288 of October 25, 1949, such tank having a partition 107 therein to dene a pressure tank 109 in the upper portion thereof, and a priming chamber 111 below.

The pressure tank and priming chamber are interconnected through a passage 113 in the partition, said passage preferably including a check valve 115 permitting flow from the priming chamber to the pressure tank, but precluding reverse flow.

A pipe opening in the priming chamber portion of the tank is marked by a pipe fitting 117 adapted to couple to the larger of the concentric pipes 101, the inner of such concentric pipes being preferably of such length as to extend into the priming chamber and terminate therein in an open end.

Coupled to the base connection opening 95 in the pump unit assembly is the pressure line 119 for such system, such line extending down into the well for coupling to the jet element (not illustrated) of a conventional injector assembly 121, to which is coupled the lower end of a suction or return line 123, which in turn, is connected to the base connection opening 97.

A check valve 125 in this return line, at a point above ground level, will function to retain the water in the upper group of stages of the pump unit assembly by preventing the same from draining away, down into the well. This check valve, therefore, will eliminate the need for a foot valve, which in a conventional system, is suspended in the water of the well from the lower end of the injector assembly. At this point, therefore, it is only necessary to have a strainer 127.

To automatically control pump unit operation in the system, the conventional pressure-switch installation 129 is included, while a service line 131 from the pressure tank portion of the tank, will permit of utilization of the water for service.

In the static or quiescent period of the pump unit, water in the stages will assure proper functioning of the system upon starting up of the pump unit. The presence of such water is assured not only by the existence of the check valve in the return line, but also by the availability of the priming chamber which is always in flow-connection with the lower stages of th pump unit, which are thus maintained submerged at all times.

When the automatic pressure switch responds to a drop in pressure in the pressure tank and initiates operation of the pump unit, the pressure developed at the output of the first or lower group of stages will drive the liquid down the pressure line through the injector assembly, and back through the return line with such additional water as will be pulled up from the well. Such water will then enter the input of the second or upper group of stages, from the output of which, it will be discharged through the larger of the concentric pipes into the priming chamber, the priming chamber in the meantime continuing to feed water through the smaller of the concentric pipes to the input of the rst or lower group of stages. All water thus pumped into the priming chamber in excess of that supplied by the priming chamber to the input of the lower group of stages, together with all entrapped air, passes through the check valve passage in the partition to enter the pressure tank, where such entrapped air will separate out to help replenish the air cushion in the pressure tank. Any excess of air cushion will be relieved through a conventional float-controlled relief valve 133 mounted in the wall of the tank at the proper level.

Upon cessation of operation of the pump unit, as when the pressure created in the pressure tank reaches its maximum permissible value determined by setting of the pressure switch, the pressure line might drain off some of its liquid, in which case there would be created a sub-atmospheric pressure condition in the pump wall passage 75, but the presence of the gooseneck, together with its air inlet valve, will block any tendency which the system might otherwise have under such condition, for siphoning off the liquid in the priming chamber.

While the return line also might similarly drain under the same conditions, the check valve will normally prevent draining from above its location in the return line. However, should such check valve fail for any reason, siphoning of the entire content of the priming chamber could occur, were it not for the presence of the air inlet valve 86, which would open and break the siphoning action when the liquid level in the priming chamber dropped to the elevation of said valve.

In fact, inasmuch as the maintenance of water in the higher situated stages is not essential in the priming of the pump unit, the check valve may be left off altogether. The only requirement, therefore, to realize this beneficial result, is that the location of the air inlet valve be at an elevation above an intermediate level in the priming chamber.

The above function of air inlet valve 86 however, is not the principal reason for its existence in the system, for its primary function is to introduce air into the system at the start of a pumping cycle, when a sub-atmosphereic pressure is apt to develop at that point in the system and in the priming chamber upon placing the pump unit in operation.

The pump unit illustrated and described above may be readily converted to an over-the-well installation by the provision of an alternative pressure line connection opening 135 in the oor of the chamber 39 and an alternative suction or return line connection opening 137 in the floor of the adjacent chamber 41. To further render the pump unit more flexible in its system applications, a connection opening 139 to the gooseneck passage may be provided in the wall of the motor bracket, and similarly, a connection opening 141 to the chamber 85 might be formed in the wall of the motor bracket. Whichever openings are not utilized in any particular installation may be plugged.

For open discharge or discharge to an overhead tank, the priming chamber and pressure tank may be eliminated by removing the

concentric pipes

101, 103 and plugging the tting 99.

A somewhat modified version .of the system of Figure l, embodying the same pump unit, is depicted in Figure 7. In this modied system, the priming chamber is independentpf thezpressuretank,it being represented .by

a small tank 143, separate Vand apart fromy the pressure: tank -145.- Connection-from the priming `chamber tankV to the pressure tank is from the roof or upper. end of thefprimingrchamber tank. In this pipe connection is located acheck Valve 149 corresponding in function to thepartition checkvalve115 in the systemof Figure 1.

In Figure 8 of the drawings, there is represented a fragmentary/:portion of the system of Figure 7, modified to take water from the pump unit through the. discharge opening 14,71, by way of a pipe connection 153, and a take-.off to the priming tank by means of a T coupling. In this case, the opening 93 about thepipe 103 mustbe sealed, .or amodified base section provided for the pump unit,d,esigned to block off the pump wall passage 79 at its lowerend. This latter method is the'one depicted in Figure 18.

In `the embodiment of the invention as illustratediin Figurey 9, the pump unit and priming chamberhave been combined into a unitaryy assembly by enclosing'a pump unit155l in an airtighttank 157.

The pump unit, like the previously described pump units,A embodiesa group of stages159 at the lower end of the pump unit, and a group of stages 161 at the upper end, of the unit the two groups being separated by a partition 163'sealed about the pump unit shaft 165 and providing a connecting channel 167 from the output of the lower group of stages to a wall passage 169. This wall passage extends upwardly and terminates above the priming-chamber in a pipefconnection fitting 171, for connection to the pressure line in a deep well installation. A snifter type or equivalent air inlet valve 173 is mounted in the-wall of said pipe connection fitting.

The partition provides a second connecting channel 175, for flow connecting a separate and independent wall passage 177 with the input of the upperI group of stages, said -wall passage, like passage 169, terminating in a pipe :connection fitting 179, and in the wall of this fitting, is mounted an air inlet valve 131. This fitting provides-for connection to the suction or return line of a deep well installation.

Admission of water from the priming chamber to the lower group of stages is by way of a cylindrical passage 183 at the lower end, in which is contained a spider 185' for supporting a bearing 187 in which the lower endyof the shaft rests.

Discharge from the uppergroup of stages is into the priming chamber by way of

openings

191 and 193 formed in the wall of a chamber 195, which corresponds to the chamber 85 of Figure 2. From the priming chamber, Water may be directed to a pressure tank through a connecting pipe 197, which includes a cheek valve 199.

By eliminating the air cushion in the pressure tank, or otherwise doing away with the pressure tank and discharging at atmospheric pressure in any of the foregoing systems, elimination of the check valve shown in the -fiow passage to the pressure tank in each instance, will 4be permitted. With the further elimination of the checkvalve 125 from the return line, as previously indicated to be a possibility, a pump system will be realized which will be completely free of check valves in the flow passages.

In any of the above described systems, the entrapment of air in the gooseneck passage and in the upper part of the suction line, between operating periods of the pump unit, might conceivably cause erratic operationof the system during starting, until such air has been forced out of the lines.

Such condition, if objectionable, may be avoided by the installation at each such point in the system, of a commercially available iioat controlled air release valve, which will function in response to a rise in level of water in the lines during the starting up period, to open a valve and release such air, which by this time will have been compressed by the rising water to above atmospheric pressure.

From the foregoing description of our invention it willV be apparent that the same not only fulfills the 0bjects attributable thereto, but is subject to additional alterations and modifications without departing from the underlying principles involved. We accordingly do not desire .toA limit ourselves in our protection to the specific details illustrated and described except as may be necessitated by the appended claims.

We claim:

1. A pump systemvcomprisinga Apump unit involving'A a plurality of impeller stages mounted `on a shaftin a'. commoncasing, said casing including at one end a base.

section and at its oppositeend, a pump lmotor bracket, partition `means dividing certain of said impeller stages from the others to form a first group of stages and av second group of stages; an injector assembly; Walls delining a primingchamber; a pressure line from the output, of said first group to said injector assembly, said` pressure line including a gooseneck rising to a point rsubstantiallyat the elevationof the upper end of sa1d primingchamber; a return line from said injector assemblyi ing a plurality of impeller stages mounted on a shaft in a common casing, said casing including at one end,-

a base `section. and at its opposite end, a pump motor bracket, means dividing certain of said impeller stages from the others to form a firstgroup of stages and a second group of stages; a pressure tank; walls defining a priming chamber; a flow connection from said priming chamber to said pressure tank; an injector assembly; a pressureline from the output of said first group to said injector assembly, said pressure line including a gooseneck rising to a point substantially at the elevation of the upper end of said priming chamber; a return line from saidinjector assembly to the input of said second group; flow connections from the input of the first group and the output of the second group to said priming chamber; and a check valve in the fiow passage from said priming chamber to said pressure tank to trap under pressure vin said pressure tank, the excess of pump unit output-to said. priming chamber over the input from said priming chamber to said pump unit.

3. A pressure system comprising a pump unit involving a plurality of impeller stages mounted on a shaft in a common casing, said casing including a-t one end, a base section and at its opposite end, a pump motor bracket, partition means dividing certain of said impeller stages from the others to form a first group of stages and a second group of stages; a pressure tank; walls defining a priming chamber; a flow connection from said `priming chamber to said pressure tank; an injector assembly; a pressure line from the output of said first group to said injector assembly, said pressure line including a gooseneck rising to a point substantially at the elevation of the upper end of said priming chamber; a return line from said injector assembly to the input of said second group; ow connections from the input of the first group and the output of the second group to said priming chamber; and a check valve in the fiow passage from said priming chamber to said pressure tank to trap under pressure in said pressure tank, the excess of pump unit output to said priming chamber over the input from said priming chamber to said pump unit.

4. A pressure system comprising a vertically disposed pump unit involving a plurality of impeller stages mounted on a shaft in a common casing, said casing including at one end, a base section and at its upperend, a pump motor bracket, means dividing certain of said impeller stages from the others to form a first group of stages and a second group of stages; a pressure tank; walls defining a priming chamber; a flow connection from said priming chamber to said pressure tank; an injector assembly; a pressure line from the output of said first group to said injector assembly, said pressure line including a goose-A neck rising to a point substantially at the upper end of said priming chamber; a return line from said injector assembly to the input of said second group; flow connections from the input of the first group and the output of the second group to said priming chamber; and a check valve in the flow passage from said priming chamber to said pressure tank to trap under pressure in said pressure tank, the excess of pump unit output to said priming chamber over the input from said priming chamber to said pump unit.

5. A pressure system comprising a vertically disposed pump unit involving a plurality of impeller stages mounted on a shaft in a common casing, said casing including at one end, a base section and at its upper end, a pump motor bracket, partition means dividing certain of said impeller stages from the others to form a rst group of stages and a second group of stages; a pressure tank;

walls defninga priming chamber; a flow connection from said priming chamber to said pressure tank; an injector assembly; a pressure line from the output of said first group to said injector assembly, said pressure line including a gooseneck rising to a point substantially at the elevation of the upper end of said priming chamber; a return line from said injector assembly to the input of said second group; iiow connections from the input of the first group and the output of the second group to said priming chamber; and a check valve in the ow passage from said priming chamber to said pressure tank to trap under pressure in said pressure tank, the excess of pump unit output to said priming chamber over the input from said priming chamber to said pump unit.

6. A pressure system comprising a vertically disposed pump unit involving a plurality of impeller stages mounted on a shaft in a common casing, said casing including at one end, a base section and at its upper end, a pump motor bracket, partition means dividing certain of said impeller stages from the others to form a lower group of stages and an upper group of stages; a tank including a partition wall having an opening therein to form a pressure tank with a priming chamber having a ow passage therefrom to said pressure tank; an injector assembly; a pressure line from the output of said lower group to said injector assembly, said pressure line including a gooseneck rising to a point substantially at the elevation of the upper end of said priming chamber; a return line from said injector assembly to the input of said upper group; ow connections from the input of the lower group and the output of the upper group, said ow connections including concentric pipes leading to said priming chamber; and a check valve in the ow passage from said priming chamber to said pressure tank to trap under pressure in said pressure tank, the excess of pump unit output to said priming chamber over the input from said priming chamber to said pump unit.

7. A pump system comprising a vertically disposed pump unit involving a plurality of impeller stages mounted on a shaft in a common casing, said casing including at one end, a base section and at its upper end, a pump motor bracket; means dividing certain of said impeller stages from the others to form a lower group of stages and an upper group of stages; walls defining a priming chamber; an injector assembly; a pressure line from the output of said lower group to said injector assembly, said pressure line including a gooseneck rising into said pump motor bracket; a return line from said injector assembly to the input of said upper group; and ilow connections from the input of the lower group and the output of the upper group to said priming chamber.

8. A pressure system comprising a vertically disposed pump unit involving a plurality of impeller stages mounted on a shaft in a common casing, said casing including at one end, a base section and at its upper end, a pump motor bracket, means dividing certain of said impeller stages from the others to form a lower group of stages and an upper group of stages; a tank including a partition wall having an opening therein to form a pressure tank with a priming chamber having a liow passage therefrom to said pressure tank; an injector assembly, a pressure line from the output of said lower group to said injector assembly, said pressure line including a gooseneck rising into said pump motor bracket; a return line from said injector assembly to the input of said upper group; ilow connections from the input of the lower group and the output of the upper group, said tiow connections including concentric pipes leading to said priming chamber; and a check valve in the ow passage from said priming chamber to said pressure tank to trap under pressure in said tank, the excess of pump unit output to said priming chamber over the input from said priming chamber to said pump unit.

9. A pressure system comprising a vertically disposed pump unit involving a plurality of impeller stages mounted on a shaft in a common casing, said casing including at one end, a base section and at its upper end, a pump motor bracket, partition means dividing certain of said impeller stages from the others to form a lower group of stages and an upper group of stages; a tank including a partition wall having an opening therein to form a pressure tank with a priming chamber having a flow passage therefrom to said pressure tank; an injector assembly; a pressure line from the output of said lower group to said injector assembly, said pressure line including a gooseneck rising into said pump motor bracket; a return line from said injector assembly to the input of said upper group; flow connections from the input of the lower group and the output of the upper group, said llow connections including concentric pipes leading to said priming chamber; and a check valve in the tlow passage from said priming chamber to said pressure tank to trap under pressure in said tank, the excess of pump unit output to said priming chamber over the input from said priming chamber to said pump unit.

10. A pressure system comprising a vertically disposed pump unit involving a plurality of impeller stages mounted on a shaft in a common casing, said casing including at one end, a base section and at its upper end, a pump motor bracket having a gooseneck integrally formed therewith, partition means dividing certain of said impeller stages from the others to form a lower group of stages and an upper group of stages; a tank including a partition wall having an opening therein to form a pressure tank with a priming chamber having a flow passage therefrom to said pressure tank; an injector assembly; a pressure line from the output of said lower group to said injector assembly, said pressure line including said gooseneck; a return line from said injector assembly to the input of said upper group; ow connections from the input of the lower group and the output of the upper group, said flow connections including concentric pipes leading to said priming chamber; and a check valve in the flow passage from said priming chamber to said pressure tank to trap under pressure in said tank, the excess of pump unit output to said priming chamber over the input from said priming chamber to said pump unit.

1l. A pump unit assembly comprising a plurality of impeller stages mounted in a common casing, said casing including at one end, a base section and at its opposite end, a pump motor bracket, means dividing certain of said impeller stages from others to form a first group of stages and a second group of stages, said means having a guide channel connecting with the output of the preceding stage belonging to the first group and a guide channel connecting with the input to the following stage belonging to the second group, a wall passage in said casing exposed at one end externally of the casing and connecting with the guide channel leading to said following stage, a second wall passage in said casing exposed at one end externally of said casing and connecting with the output of a subsequent stage in said second group, a third wall passage in said casing connecting with the guide channel leading from said preceding stage, said third wall passage terminating in an exposed opening at the upper end of said stages, a fourth wall passage in said casing exposed at one end externally of said casing and terminating in an exposed opening at the upper end of said stages, and means within the pump motor bracket interconnecting said last two passages at said exposed openings.

l2. A pump unit assembly comprising a plurality of impeller stages mounted in a common casing, said casing including at one end, a base section and at its opposite end, a pump motor bracket, means dividing certain of said impeller stages from others to form a first group of stages and a second group of stages, said means having a guide channel connecting with the output of the preceding stage belonging to the rst group and a guide channel connecting with the input to the following stage belonging to the second group, a wall passage in said casing exposed at one end externally of the casing and connecting with the guide channel leading to said following stage, a second wall passage in said casing exposed at one end externally of said casing and connecting with the output of a subsequent stage in said second group, a third wall passage in said casing connecting with the guide channel leading from said preceding stage, said third wall passage terminating in an exposed opening at the upper end of said stages, a fourth wall passage in said casing exposed at one end externally of said casing and terminating in an exposed opening at the upper end of said stages, means within the pump motor bracket interconnecting said last two passages at said exposed openings, and an air inlet valve in said passage interconnecting means.

13. A pump unit assembly comprising a plurality of vertically disposed impeller stages mounted in a common casing, said casing including at its lower end, a base section and at its upper end, a pump motor bracket, partitioning means dividing certain of said impeller stages from others to form a rst group of stages and a second group of stages, said partitioning means having a guide channel connecting with the output of the preceding stage belonging to the first group and a guide channel connecting with the input to the following stage belonging to the second group, a wall passage in said casing exposed at one end externally of the casing and connecting with the partition guide channel leading to said following stage, a second wall passage in said casing exposed at one end externally of said casing and connecting with the output of a subsequent stage in said second group, a third wall passage in said casing connecting with the partition guide channel leading from the preceding stage, said third wall passage terminating in an exposed opening at the upper end of said stages, a. fourth wall passage in said casing exposed at one end externally of said casing and terminating in an exposed opening at the upper end of said stages, means within the pump motor bracket interconnecting said last two passages at said exposed openings, said means involving a gooseneck formed integrally with said bracket, and an air inlet valve in said gooseneck.

14. A pump system comprising a pump unit involving a plurality of stages mounted in a common casing, partition means dividing certain of said stages from the others to form a first group of stages and a second group of stages; an injector assembly; walls defining a priming chamber; a pressure line from the output of said first group to said injector assembly; a return line from said injector assembly to the input of said second group; and iiow connections from the input of said first group and the output of said second group to said priming chamber.

15. A pump system comprising a pump unit involving a plurality of stages mounted in a common casing, partition means dividing certain of said stages from the others to form a first group of stages and a second group of stages; an injector assembly; walls defining a priming chamber enclosing said pump unit; a pressure line from the output of said first group to said injector assembly; a return line from said injector assembly to the input of said second group; and fiow connections from the input of said first group and the output of said second group to said priming chamber.

16. A pump system comprising a plurality of stages; an injector assembly; walls defining a priming chamber of greater elevation than certain of said stages; a pressure line from one of said stages to said injector assembly; a return line from said injector assembly to a different one of said stages; a liow connection from said priming chamber to a stage of lower elevation; a ow connection from a high pressure stage to said priming chamber; air inlet valve means in the flow path from said one stage to said injector assembly and at an elevation higher than an intermediate level in said priming chamber; and air inlet valve means in the ow path from said injector assembly to said priming chamber and at an elevation above an intermediate level in said priming chamber.

References Cited in the le of this patent UNITED STATES PATENTS Name