US2274763A - Centrifugal pump - Google Patents

Description

March 3, 1942. DE wrr1 E.l YATEs 2,274,763

` I GENTRIFUGAL PUMP Filed April 18, 1940 s sheets-sheet 1 March 3, 1942. DE wn-r mms 42,274,763

GENTRIFUGAL lPUMP Filed April 18, 1940 s sheets-sheet 2 March 3, V1942.

GEIITRIISUGALl PUMP Filed April 18, 1940 3 Sheets-Sheet 5 0 j f /Z 72 7o l I! Vazi f Y 2 7 f fl. Il' 57 5 I I 35 20 3 y,/ 6

. i 6 70 c I/ 5 'f 6- ga? 76 l 27 60 \w J0V f2 l l .kmh eWZZJZE? Patented Mar. 3. 1942 UNITED STATES PATENT OFFICE 2,274,763 CENTRIFUGAL PUMP De Witt E. Yates, Chippewa Falls, Wis., assignor to W. S. Darley & Company, Chicago, Ill., a corporation of Illinois Application April 18, 1940, Serial No; 330,230 c claims. (ol. 10s-106) The present invention relates generally to parallel-series 2-stage centrifugal pumps. More particularly the invention relates to that type of 2-stage centrifugal pump which is primarily designed for use as one of the main or principal operating parts of an engine driven lire fighting vehicle, is adapted to be driven from the driven shaft of the vehicle transmission through the medium of clutch controlled speed increasing gearing and comprises as its main parts (l) a spiral or volute pump casing which is located at one side of the driven shaft of the transmission and is shaped to define a pair of laterally spaced pump chambers, (2) a pump shaft which is connected for drive by the speed increasing gearing and is suitably journalled in bearings in the end walls of the pump casing so that it extends in parallel relation with the driven shaft of the vehicle transmission, (3) two impellers which are mounted in the pump chambers respectively and are iixedly secured to the pump shaft, and (4) a valve mechanism which is associated with the pump casing and serves to control the pump so that it may be operated in parallel or series.

One object of the invention is to provide a centrifugal pump of this type which is generally an improvement upon, and has certain advantages over, previously designed pumps of the same character.

Another object of the invention is to provide a parallel-series 2-stage centrifugal pump of the aforementioned type in which the valve mechanism for controlling the pump for parallel or series operation is of novel design and comprises a manifold above the pump casing and a single,

readily manipulable control valve.

Another object of the invention is to provide Va pump of the last mentioned type in which the pump casing has upwardly facing suction' and discharge ports in the top face thereof and themanifold of the valve mechanism has registering downwardly facing suction and discharge ports and embodies means whereby a supply hose and one or more discharge hoses may be connected to it.

A further object of the invention is to providev a centrifugal pump of the aforementioned type and character which occupies but a minimum amount of space by reason of the fact that the pump is so positioned that the portion of the pump casing of smallest or least radius is disposed adjacent the driven shaft of the transmission of the vehicle with which the pump is used.

A still further object of the invention is to provide a parallel-series 2-stage centrifugal pump centrifugal pump will be apparent from a consideration of the following detailed description.

The invention consistsin the several novel features which are hereinafter set forth and are more particularly defined'by claims at the conclusion hereof.

In the drawings which accompany and form a part of this specification or disclosure and in which like numerals of reference denote corresponding parts throughout the several views:

Figure 1 is an end view of a pump embodying the invention;

Figure 2 is a horizontal section taken on the line 2 2 of Figure 1 and illustrating in detail the construction and design of the pump casing and the two impellers;

Figure 3 is a' horizontal section taken on the line 3-3 of Figure 1 and showing the construction and design of the manifold and valve which vconstitute the valve mechanism for controlling the pump for parallel or series operation;

Figure 4 is a horizontal section taken on the line 4-4 of Figure 1 anddisclosing the arrangement of the suction and discharge ports in the bottom of the manifold of the valve mechanism;

Figure 5 is a horizontal section taken on the line 5-5 of Figure 1 and illustrating the' arrangement of the suction and discharge ports in the top of the Dump casing; f

Figures 6 and 7 are vertical longitudinal sections taken on the lines 6-6 and 'I-'I of Figure 3 respectively; and

Figure 8 is a perspective of the single manually manipulable valve of the valve mechanism.

The pump which is shown in the drawings constitutes the preferred embodiment of the invention. It is essentially a parallel-series 2-stage centrifugal pump and is primarily designed for use'in connection with an engine driven re lighting vehicle (not shown) having a horizontally extending driven shaft 9 leading from its transmission and adapted, as hereinafter described and during engine operation, to drive a propeller shaft I0 for the rear or traction wheels of the vehicle or the pump. As shown in Figure 2, the rear end of the driven shaft 9 of the transmission extends into one end of a horizontally elongated gearing housing II and the propeller shaft I0 is longitudinally aligned with the shaft 9 and is journaled in a vpair of ball bearings in the `end walls of an elongated housing I2. The housing II is suitably supported with respect to the chassis of the vehicle to which the pump is applied and comprises a frontI wall I3, a rear wall I4 and a continuous side Wall I5.l The housing I2 is suitably supported with respect to the housing I I and has the front end wall thereof in abut-y ment with the rear wall I4 of the housing II.l

The side wallV of the housing I2 is semicircular in cross Section and is so arranged or positioned tral portion of the pump casing 4G.

that the open part thereof faces laterally. The pump is located adjacent the front end of the propeller shaft IG, as shown in Figure'fl'. It comprises a pump casing I6, a pump shaft ll', a pair of impellers i8 and 9 and a valve mechanism 2i). mechanism controls the pump for parallel or series operation. The pump casing l comprises a front end wall 2|, a rear end wall 22 and a spiral or volute side wall 23. These three walls are suitably secured together. The front end wall 2| is bolted to the housing and is shaped to define a central chamber 24 and a hub part 25 within the chamber. The rear end wall 22 of the pump casing is positioned in spaced relation with the front end wall and is separated from the latter by way of the spiral or volute side wall 23. Said side wall has a horizontally elongated extension 2B at the top portion thereof and this extension overlies the propeller shaft housing l2 and has a flat top face 2l, as best shown in Figure 6. In addition to the extension 25 the side wall 23 of the pump casing has an inwardly extending ring shaped front web 28, an inwardly extending ring shaped intermediate vweb 29 and an inwardly extending ring shaped rear web 32. These webs are preferably formed as integral parts lof the side wall of the pump casing. The space between the front web 28 and the intermediate web 2S constitutes a first stage suction chamber Si and the space between the front web 28 and the front end wall 2| of the pump casing IS constitutes a first stage pump chamber 32. The space between the intermediate web 29 and the rear web 30 constitutes or forms a second stage suction chamber 33 and the space between the rear web 32 and the rear end wall 22 of the pump casing constitutes a second stage pump chamber 34. A rectangular first stage suction port 35 is formed in the flat top face 21 of the extension 26 of the pump casing and this port leads to, and communicates with, the rst stage suction chamber 3i. A rectangular second stage suction port 3S is also formed in said flat top face 2l and this port leads to, and communicates with, the second stage suction chamber 33. The two ports 35 and 35 are positioned in side by side relation, as shown in Figure 6, and are located in what may be termed the outer end portion of the extension 26. in addition to the two ports 35 and 36 the fiat top face 2 of the extension 26 has a rst stage discharge port 37 and a second stage discharge port 33. These two ports are positioned in side by side relation and are located in the inner or other end portion cf the extension 2E. The port 37 communicates with the peripheral discharge portion of the first stage pump chamber 32, as shown in Figure 6. The second stage discharge port 38 leads to, and communicates with, the peripheral discharge portion of the second stage pump chamber 36|. The pump casing it, as shown in Figures 6 and '7, is positioned so that the part of least radius is adjacent the front end of the propeller shaft IQ. As a result of this the pump as a whole occupies but a comparatively small space and is extremely compact.

The pump shaft il carries the two impellers i8 and I9 and extends horizontally. It is positioned in parallel relation with the driven shaft 9 and the propeller shaft l!) of the vehicle with which the pump is associated, and is located in the cen- The rear end of the pump shaft is jouinaled in a bearing in the central portion of the rear end wall 22 of As hereinafter described, the valve-- stage suction chambers 3| and 33.

i shown in Figure 2, and is supported or carried by a ball bearing fifi in the front Wall |3 of the housing I, and a ball bearing 4| in the front end Wall 2| of the pump casing I6. A packing gland in the form of a follower 42 and packing material 43 serves to prevent leakage at the point Where the front end of the pump shaft passes through the front end wall 2| of the pump casing. The packing material is mounted within the hub part 25 in the chamber and the follower 42 is mounted on the shaft as shown in Figure 2. The pump shaft is adapted to be driven from the driven shaft 9 of the vehicle transmission by way of a gear 44and a pinion 45. The gear 44 is loosely mounted on the rear end of the driven shaft 9 and meshes with the pinion 45. The latter is keyed or otherwise xedly secured to the portion of the front end of the pump shaft which is disposed in the housing A clutch gear 46 is connected for drive by, and is longitudinally slidable on, the rear end of the shaft 9. This gear has an internal series of clutch teeth 4'! at the ront end thereof and these teeth are adapted,

when the gear. 46 is shifted forwards, to engage an external series of teeth 43 on the hub part of the gear 44- and establish a driving connection between the shaft 9 and the gear. When such connection is established the pump shaft 'l is connected for drive by the driven shaft 9 through the medium of the clutch gear 46, gear 44 and the pinion 45. The rear end of the clutch gear is provided with an interna-l series of teeth 49 and these teeth are adapted, in response to rearward shift of the clutch gear, to mesh with a pinion 5G on the front end of the propeller shaft l0 and form a driving connection between the driven shaft 9 and the propeller shaft. When it is desired to operate the pump the clutch gear 46 is shifted forwards and when it is desired to propel the Vehicle with which the pump is associated the gear is shifted rearwards in order to bring the internal teeth 49 into meshing relation with the pinion til. The clutch gear 46 is so constructed that when it is effective to establish a driving connection between the driven shaft 9 and the gear 44 the teeth 49 thereof are out of mesh with the pinion as shown in Figure 2. Forward and rearward shift of the clutch gear is effected by means of a lever 5| which is externally disposed with respect to the housing and has suitable locking means applied to it. By reason of the fact that the pump casing i5 is arranged so that the portion of least radius is adjacent the propeller shaft the pump shaft is positioned as closely as possible to the driven shaft 9 and the propeller shaft t0, and hence only comparatively small gears are necessary to effect driving of the pump shaft from the driven shaft.

The impeller I8 of the pump is mounted in the rst stage pump chamber 32 and in connection with series operation of the pump constitutes the rst stage impeller. It is of hollow design and embodies an annular series of outwardly extending arcuate passages 52 and also embodies a hub 53 which is iixedly Vsecured to the pump shaft I1 and has a suction opening 54. The latter is located at the inner ends of the passages 52 and communicates with the first stage suction chamber 32. When the pump is in operation the liquid to be pumped is drawn into the rst suction chamber 32, as hereinafter described. It is then flung outwards through the passages 52 into the peripheral discharge portion of the chamber 32. From this chamber the liquid under pressure is delivered to the first stage discharge port 31 in the top face of the extension 26. The impeller I9 is disposed in the second stage pump chamber 34 and operates as the second stage impeller when the pump is under series operation. It is similar in design to the impeller I8 but is reversely positioned. As shown in Figure 2, theimpeller I9 comprises an annular series of outwardly extending arcuate passages 55 and a hub 56. The hub is fixedly secured in any suitable manner to the pump shaft II and has a suction opening 51 which faces, and communicates with, the inner portion of the second stage suction chamber 33 and leads to the inner ends of the passages 55. When the pump is in operation the liquid to be pumped is drawn into the second stage suction chamber 33 and is then flung outwards into the peripheral discharge portion of the chamber 34 due to the angularity of the passages 55. The liquid in the peripheral discharge portion of the chamber 34 is under pressure and iows to the second stage discharge port 38 in the top face of the extension 26.

The valve mechanism 26 serves so to control the pump that the latter may be operated in parallel or series. When the pump is operated in parallel the pump pumps twice as much'liquid than when it is operated in series although the and are of suchv length that the inner ends thereof terminate adjacent the central portion of the manifold interior. tioned midway between the side walls 62 and 63 and the web 66, as shown in Figure 5, is located between the web 61 and the side wall 62. 'The webs 64 and 61 are substantially longitudinally aligned and the webs 65 and 66 are laterally offset. The spacey between the side wall 62 and the webs 64 and 66 constitutes a longitudinally extending inlet or suction duct 16. The space between the side wall 63 of the manifold and the webs 65 and 61 constitutes a longitudinally pressure of the pumped liquid is but half asmuch as the pressure of the liquid which is pumped when the pump is operated in series. As shown in Figure 3, the valve mechanism 26 consists of a manifold 58 and a rotary valve 56.

The manifold is preferably in the form of a one piece box-like casting. It is mounted on, and extends longitudinally of, the top extension 26 of the pump casing I6 and consists of a bottom wall 60, a top wall 6I anda pair of side walls 62 and 63. The two side walls of the manifold extend between, and are formed integrally with, the side margins of the top and Abottom walls and serve' to maintain the latter walls in vertically spaced relation. In addition to the bottom, top and side walls the manifold 58 comprises a pair of vertically extending laterally spaced webs 64 and 65 and a pair of vertically extending laterally spaced webs 66 and.61. The webs 66 and 64 are located in the end of the manifold which overlies the end of the top extension 26 having the first stage and second stage suction ports and 36. They extend between, and are connected to, the bottom and top walls of the manifold and are joined together at their outer ends, as shown in Figure 3. The inner ends of the two webs 64 and 65 terminate adjacent the central portion of Vthe manifold interior. `The web 64 is centrally positioned with respect to the side walls 62 and 63 and the web 65 is disposed between the web 64 and the side wall 63, and defines with said web 64 a second stage suction passage 66. The webs 66 and 61 extend between, and are connected to, the bottom and top walls of the manifold and define between them a first stage discharge passage 69. They are joined together at their outer ends extending discharge duct 1I. The ends of the manifold are closed by means of a pair of fittings 12. Each fitting comprises an inlet nipple 13 and a pair of discharge nipples 14. The inlet nipples of the fittings communicate with the suction duct 1D and have externally threaded extremities whereby hoses may be connected to them. When the pump is not in use the inlet nipples are closed .by means of screw caps 15. The discharge nipples 14 of the fittings 12 communicate with the ends of the discharge duct 1I, as illustrated in Figure 5. 'They have externally threaded outer extremities (not shown) whereby hoses may be connected to them, and in addition have valves 16 for controlling purposes. Screw caps 11 serve to close the discharge nipples when the pump is inoperative. A first stage suction port 18, a second stage suction port 19, a first stage discharge port 86 and a second stage discharge port 8I are formed in the bottom wall 60 of the manifold 58. The first stage suction port 19 is in communication with the suction duct 16 and is located ladjacent the bottom of the web 64. It overlies, and communicates with, the rst stage suction port 35 inthe top extension 26 of the pump casing and, together with the last mentioned port, establishes communication between the duct 16 and the first stage suction chamber 3|. The second stage suction port 19 is located at the bottom of the suction passage 68 between the two webs 64 and and overlies, and registers with, the second stage suction port 36 in-the top extension 26. The two ports 19 and 36 establish communication between the suction passage 68 and the second stage suction chamber 33 in the pump casing I6. The first stage discharge port 86 is located at the bottom of the first stage discharge passage 69 and overlies, and registers with, the rst stage discharge port 31. The latter port, together with the port 86, establishes communication between the peripheral discharge portion of the first stage pump chamber 3| in the pump casing and the vertically extending discharge passage 69 in the manifold. The second stage discharge port 8| is located at the bottom of the discharge duct 1I and is positioned between the web 61 andthe opposed portion of the side wall 63 of the manifold. It overlies and registers with the second stage discharge port 38 in the top extension 26 of the pump casing and establishes communication between the peripheral discharge portion of the second stage pump chamber 34 and the longitudinal discharge duct 1I in the manifold. v

The valve 59 of the valve mechanism 2|] is vertically elongated and ts rotatably in the t space between the inner ends of the webs 64, 65, 66 and 61. It is manually manipulable, as hereinafter described, and comprises a circular bottom 82,'a circular top 6 3,Y apair of vertically extending webs 84 and 65, and a stem 86. The

The web 61 is posi-v circular bottom 82 of the valve is rotatably mounted in a circular hole 8T in the bottom Wall 69 of the manifold 58. The circular -top 83 is vertically aligned with, and is the same in diameter as, the bottom 82 and is rotatably mounted in a circular hole 88 in the top Wall 8| of the manifold. The stem 86 projects upwardly from the central portion of the top 83 and has keyed to the upper end thereof a radially extending handle 89 whereby the valve may be rotated relatively to the manifold. The top extension 26 of the pump casing I8 serves to hold the valve 59 against downward displacement with respect to the manifold. Upward displacement of the valve is prevented :by means of a cap type plate 99 which overlies the top 83 and is bolted or otherwise xedly secured to the manifold top 6I, as shown in Figures 1 and '7. The stem 85 of the valve extends through a circular hole in the plate 98. The two vertically extending websl 84 and 85 extend between the bottom 82 and the top 83 of the valve and serve to maintain the latter in vertically spaced relation. The web 85 is segmentally shaped as far as cross section is concerned and is located adjacent the peripheral or marginal portions of the valve bottom and top. It is adapted when the valve is in position for parallel pump operation to fit against a curved extension Bia on the innerend of the web 6l. When the valve is set for series pump operation, as hereinafter described, the web 85 serves to bridge and close the space between the inner end of said extension 67a and the inner end of the web 85. The web 84 is arcuate in cross section and is arranged so that the central portion thereof is at the center of the valve and its ends terminate adjacent the peripheral or marginal portions of the valve bottom and top and extend away from the web 61. Because of the arrangement of the web 84 the valve has a passage 9| of crescent shape cross section between the webs 84 and 85 and embodies, outwardly of the web 84, a passage 92 of substantially elliptical cross section. When the valve 59 is in position for parallel operation of the pump the web 84, as shown in full lines in Figure 3, bridges the inner ends of the webs 55 and 66 with the result that the suction passage 68 is in communication with the suction duct TI) via the passage 92 in the valve and the first stage discharge passage 69 between the webs 65 and 81 is in communication with the discharge duct '|I by way of the passage 9|. When the valve is in position for series pump operation (see dotted lines in Figure 3) the web 84 extends between the inner ends of the webs 64 and 68 and the web 85 extends between the inner ends of the Webs 65 and 6i, as hereinbefore described. With the webs in such position the second stage suction passage 68 is cut off from the suction duct '|11 by the web 84 and is in communication with the first stage discharge passage 69 by way of the passage 9| in the valve.

Assuming that the pump shaft I 'I is being driven from the driven shaft 9 of the transmission of the vehicle with which the pump is associated and the valve 59 is in position for parallel pump operation the operation of the pump is as follows: The impellers I8 and I9 create suction in their respective pump chambers 32 and 34. This suction causes the liquid to be pumped to be drawn into the suction duct I through either or both of the nipples 'I3 of the fittings '|2. Part of such liquid flows downwardly through the first stage suction port 18 -in the manifold, then through the first stage suction port 35 in the top extension 26 of the pump casing I6 and thence into the first stage suction chamber 3|. From such chamber such part of the liquid flows outwardly under pressure through the passages 52 in the impeller I8 and then passes from the peripheral discharge portion of the pump chamber 32 into the first stage discharge passage 69 in the manifold via the first stage discharge port 31 inthe top extension 26 of the pump casing and the first state discharge port in the bottom wall of the manifold. From the first stage discharge passage 69 the part of the pumped liquid which is subjected to the action of the impeller I8 flows through the passage 9| in the valve and then into the discharge duct '|I. The remainder of the liquid which is drawn into the suction passage in the manifold fiows through the passage 92 in the valve, then downwardly through the second stage suction passage 68 and into the suction chamber 33 in the pump casing via the second stage suction ports 'I9 and 36. From the second stage suction chamber 33 the liquid is drawn into the openings 5'| in the hub 56 of the impeller I9 and is then flung or thrown out- -wards under pressure into the peripheral discharge portion of the pump chamber 34. From such portion of the pump chamber 34 the pumped liquid flows upwardly into the discharge duct 7| in the manifold via the second stage discharge ports 38 and 8|. From the discharge duct |I the pumped liquid, i. e., the liquid which is pumped by the two impellers I8 and I9, is discharged through any or all of the discharge nipples 14. When the valve 58 is set for parallel pump operation half of the liquid to lbe pumped is pumped by the impeller I8 and the other half is pumped by the impeller I9. During parallel operation of the pump the pump pumpsI twice the volume of liquid but the liquid is only under half as much pressure as when the pump is set for series operation. When the Valve 59 is set or turned for series pump operation the liquid to be pumped is drawn into the suction duct 1D in the manifold through either or both of the nipples |3 on the fittings 12. The liquid then flows downwardly through the first stage suction ports T9 land 35 into the first stage suction chamber 3| in the pump casing I8, it being understood and apparent that no liquid is permitted to fiow directly from the duct 1|! into the second stage suction passage E9 in the manifold because such passage is closed from the duct I9 due to the position of the web 84 of the valve 58. From the first stage suction chamber 3| in the pump casing I6 the liquid is drawn into the opening 54 in the hub 53 of the impeller I8 and is then flung or forced out- Wardly under pressure through the outwardly extending arcuate passages 52 in said impeller. From the peripheral discharge portion of the pump chamber 32 the pumped liquid travels upwards into the first stage discharge passage B9 in the manifold 58 via the first stage discharge port 31 in the top extension 26 and the rst stage discharge port 8i) in the manifold. `From the discharge passage 69 the pumped liquid flows through the passage 9| in the valve 59 into the second stage suction passage 59 between the webs 64 and 65. From such passage the liquid iiows downwardly through the second stage suction ports '|9 and 36 into the second stage suction chamber 33 in the pump casing I6. From such chamber the liquid under pressure enters 2mg/esi the passages 55 in the impeller I9 and is flung outwards under increased pressure into the peripheral discharge portion ofthe secondv stage pump chamber 34. From this chamber the liquid flows upwardly through the registering second stage discharge ports 38 and 8| into the discharge duct H in the manifold 58. From such duct the pumped liquid flows through any or all of the nipples I4 to the point of use. Preferably suitable stop means (not shown) is employed to limit the valve 59 so that it may be turned back and forth between its parallel and series positions only.

When it is desired to operate the pump the operator manipulates the lever 5I on the housing Il so as to bring the clutch gear 46 into clutched relation with the gear 44 on the rear end of the driven shaft 9. When the clutch gear is in such position drive of the shaft 9 operates through the medium of the clutch gear, the gear 44 and the pinion 45 to drive the pump shaft l1 of the pump. When the pump il is driven the pump may be operated in parallel or series by proper manipulation of the valve 59 of the valve mechanism 2i). When it is desired to have the pump operate in parallel the valve 5S is rotated into the position shown in full lines in Figure 5. When it is desired to have the pump operate in series the valve 59 is turned by manipulation of the handle 89 into the position shown in dotted lines in Figure 5. When the pump is not to be used the clutch gear 46 is shifted rearwards by the control lever 5l. As soon as the clutch gear is rearwardly shifted the gear 44 is declutched from the driven shaft 9 and hence the driving connection between the shaft 9 and the pump shaft is rendered inoperative. To effect drive of the vehicle with which the pump is used the propeller shaft i for the rear or traction wheels is coupled to the driven shaft 9 by rearward shift of the clutch gear 46.

The herein described pump occupies but a small amount of space due to the arrangement of the valve mechanism 2i) and the position of the pump casing I6 with respect to the propeller shaft l0. By reason of the fact that the two impeller wheels are arranged in reverse relation, i. e., with their suction openings facingvone another, the pump casing is not of undue length. The pump as a whole is efficient in operation and because of its simplicity may be manufactured at a low and reasonable cost.

Whereas the pump has been described as being primarily designed for use with a re iighting vehicle it is to be understood that it has other capabilities of use. It is also to be understood that the invention is not to be restricted to the details set forth since these may be modified within the scope of the appended claims without departing from the spirit and scope of the invention.

Having thus described the invention what I claim as new and desire to secure by Letters Patent is:

1. A centrifugal pump comprising a pump casing having a pair of suction chambers and a pair of pump chambers disposed in laterally spaced relation therein and embodying in one part of the side wall thereof a pair of suction ports leading to the suction chambers respectively and a pair of discharge ports leading from the pump chambers respectively, a pair of rotary impellers disposed in the pump chambers respectively. and a valve mechanism for controlling the pump for parallel or series operation, consisting of a separately formed box-like manifold having one wall thereof in abutment with said one part of the side wall of the pump casing, and embodyingin its interior a suction duct, an independent discharge duct, a pair of laterally spaced passage forming webs between the two ducts, and a second pair of laterally spaced passage forming webs between said ducts and in opposed relation with the first mentioned pair of webs, and embodying in said one wall thereof a first suction port in registry with one of the suction ports in the pump casing and in direct communication with the suction duct, a second suction port in registry with the other suction port in the pump casing and in communication with the passage between said rst mentioned pair of webs, a rst discharge port in registry with one of the discharge ports in the pump casing and in communication with the passage between said second pair of webs, and a second discharge port in registry with the other discharge port in the pump casing and in direct communication with the discharge duct, 4and a single valve in the manifold between the inner ends of the manifold webs, provided with a pair of laterally spaced webs defining a pair of passages, and arranged and designed so that it is rotatable back and forth between a parallel pump position wherein one of its passages establishes communication between the passage between the said first mentioned pair of manifold webs and the suction duct and its other passage establishes communication between the passage between the second pair of manifold webs and the discharge duct and a series pump position wherein its two webs bridge said inner ends of the manifold webs and its said other passage establishes communication between the two passages that are formed by the two pairs of manifold webs.

2. A centrifugal pump comprising a pump casing arranged so that the axis thereof extends horizontally and having a pair of suction lchambers and a pair of pump chambers therein and in addition having on the top portion of the side wall thereof an elongated extension provided with a flat upper face and having a pair of side by side suction ports extending through one end of said face and leading to the suction chambers respectively and a pair of side by side discharge ports extending through the other end of said face and leading from the pump chambers respectively, a pair of rotary impellers mounted in the pump chambers respectively, and a valve mechanism for controlling the pump for parallel or series operation, embodying an elongated box-like manifold extending longitudinally of but formed separately from the extension and having a bottom wall in abutment with the flat upper face of said extension and also having a longitudinally extending suction duct at one side thereof, a longitudinal discharge duct at its other side, a pair of side by side suction ports extending through one end of said bottom wall and registering respectively with the suction ports in said extension, and a pair of side by side discharge ports extending through the other end of said bottom wall and registering respectively with the discharge ports in the extension, and a single valve mounted in the manifold and shiftable back and forth between a parallel pump position wherein the manifold suction ports are both in communication with the suction duct and the manifold discharge ports are both in communication with the discharge duct and a series pump position wherein one of the manifold suction ports is in communication with the suction duct, the other manifold suction port is in communication with one of the manifold discharge ports, and the other manifold discharge port is in communication with the discharge duct.

3. A centrifugal pump comprising a pump casing arranged so that the axis thereof extends horizontally and having a pair of separate but contiguous suction chambers in the central portion thereof and a pair of pump chambers at the sides of said suction chambers and with the central portions thereof in communication with the central portions of the suction chambers respectively, and in addition having on the top portion of the side Wall thereof an elongated extension provided with a fiat upper face and embodying a pair of side by side suction ports extending through one end of said flat upper face and leading respectively to the suction chambers and a pair of side by side discharge ports extending through the other end of said upper face and leading respectively from the pump chambers, and a valve mechanism for controlling the pump for parallel or series operation, consisting of an elongated box-like manifold disposed above and extending longitudinally of said extension, embodying an elongated bottom wall in abutment with the at upper face of the extension and having in its interior a longitudinally extending suction duct at one side, a longitudinal discharge duct at the other side, a pair of laterally spaced longitudinally extending upstanding passage forming webs between the two ducts and in one end thereof, and a second pair of laterally spaced longitudinally extending upstanding passage forming Webs between said ducts and in its other end and in opposed relation with the first mentioned pair of webs, and having in its said bottom wall a first suction port in registry with one of the suction ports in the pump casing and in direct communication with the suction duct. a second suction port in registry with the other suction port in the pump casing and in communication with the passage between said first mentioned pair of webs, a rst discharge port in registry with one of the discharge ports in the pump casing and in communication with the passage between said second pair of webs, and a second discharge port in registry' with the other discharge port in the pump casing and in direct communication with the discharge duct, and a single valve in the manifold between the inner ends of the manifold webs, provided with a pair of laterally spaced webs defining a pair of passages, and arranged and designed so that it is rotatable back and forth between a parallel pump position wherein one of its passages establishes communication between the passage between the said rst mentioned pair of manifold webs and the suction duct and its other passage establishes communication between the passage between the second pair of manifold webs and the discharge duct and a series pump position wherein its two webs bridge said inner ends of the manifold webs and its said other passage establishes communication between the two passages that are formed by the two pairs of manifold webs.

4. A pump structure comprising a driven shaft, a coaxial second shaft, a volute pump casing located at one side of, and in transverse alignment with, the second shaft and arranged so that the portion of the side wall thereof of least radius is immediately adjacent said second shaft, a pump shaft extending through the casing and in parallel relation with the driven and second shafts, an impeller disposed in the casing and fixed to the pump shaft, and clutch controlled gearing for connecting the driven shaft to drive either the pump shaft or said second shaft.

5. A pump structure comprising a horizontal driven shaft, a coaxial second shaft, a volute pump casing positioned at one side of, and in transverse alignment with, the second shaft and so that the portion of the side wall thereof of least radius is immediately adjacent said second shaft, and having a top extension directly overhanging said second shaft and provided with upwardly facing suction and discharge ports therein, a pump shaft extending through the casing and in parallel relation with the driven and second shafts, an impeller disposed in the casing and fixed to the pump shaft, and clutch controlled gearing for connecting the driven shaft to drive either the pump shaft or said second shaft.

6. A pump structure comprising in combination a driven shaft, a coaxial second shaft, a volute pump casing positioned at one side of the second shaft and sothat the portion of the side Wall thereof of least radius is substantially in abutment with said second shaft, and having a pair of suction chambers and a pair of pump chambers therein and in addition an elongated extension on the side wall thereof overhanging said second shaft and provided in one end thereof with a pair of laterally spaced suction ports leading to the suction chambers respectively and in its other end with a pair of discharge ports leading from the pump chambers respectively, a pump shaft extending through the casing and disposed in parallel relation with said driven and second shafts, a pair of rotary impellers fixed to the pump shaft and disposed in the pump chambers respectively, clutch controlled gearing for connecting the driven shaft to drive either the pump shaft or said second shaft, and a valve mechanism for controlling the pump part of the structure for parallel or series operation embodying an elongated manifold connected to, and extending longitudinally of, said extension and having a longitudinally extending suction duct at one side thereof and a longitudinal discharge duct at its other side and also having a pair of laterally spaced suction ports registering respectively with the suction ports of the pump casing and a pair of discharge ports registering respectively with the discharge ports of said pump casing, and a valve mounted in the manifold and shiftable back and forth between a position wherein the manifold suction ports are vboth in communication with the suction duct and the manifold discharge ports are both in communication with the discharge duct anda position wherein one of the manifold suction ports is in communication with thersuction duct, the other manifold suction port is in communication with one of the manifold discharge ports, and the other manifold discharge port is in communication with the discharge duct.

DE WITT E. YATES.

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