Multi-Stage Pump

This invention relates to multi-stage pumps, and, more particularly, to multi-stage pumps of the double-suction type.

It is a primary object of the present invention to afford a novel multi-stage pump.

Another object of the present invention is to afford a novel multi-stage pump of the double-suction type, that is, a pump having two inlet openings from which liquid is fed into a common discharge opening.

A further object of the present invention is to afford a novel pump having substantially double the capacity of a pump of the one end suction-one end discharge type, without increasing the size of the liners, casings or impellers, thereof.

Another object of the present invention is to afford a novel multi-stage pump of the double-suction type which is effective to pump liquids, such as, for example, liquified gases, at or near the boiling points thereof, as well as being effective to pump other liquids, such as, for example, water.

Multi-stage pumps for pumping liquids, at or near the boiling points thereof, have been heretofore known in the art, being shown, for example, in U.S. Pat. No. 2,875,968, issued to L. C. Roth, on Mar. 3, 1959, and my earlier U.S. Pat. No. 3,963,371, issued on June 15, 1976. Such pumps have been highly successful. It is an important object of the present invention to afford improvements over the multi-stage pumps heretofore known in the art.

Another object of the present invention is to afford a novel multi-stage pump, of the double-suction type, wherein liquid enters through oppositely disposed ends of the pump and is discharged through a common, centrally located discharge passageway.

Yet another object of the present invention is to afford a novel double-suction, multi-stage pump of the aforementioned type which is modular in construction, and is constructed in such a manner that the various stages hereof may be readily assembled and separated, relative to each other.

A further object of the present invention is to afford a novel double-suction, multi-stage pump, having the aforementioned modular construction, which is of a combination centrifugal-turbine type.

Another object of the present invention is to afford a novel double-suction, multi-stage pump of the aforementioned type which is practical and efficient in operation, and which may be readily and economically produced commercially.

Other and further objects of the present invention will be apparent from the following description and claims and are illustrated in the accompanying drawings which, by way of illustration, show the preferred embodiment of the present invention and the principles thereof and what I now consider to be the best mode which I have contemplated applying these principles. Other embodiments of the invention embodying the same or equivalent principles may be used and structural changes may be made as desired by those skilled in the art without departing from the present invention and the purview of the appended claims.

In the drawings:

FIG. 1 is a longitudinal sectional view through a double-suction, multi-stage pump embodying the principles of the present invention; and

FIG. 2 is an enlarged, detail, longitudinal sectional view through one end portion of the pump shown in FIG. 1.

A pump 1, embodying the principles of the present invention, is shown in the drawings to illustrate the presently preferred embodiment of the present invention.

The pump 1 embodies two elongated end sections 2 and 2a disposed in longitudinal alignment with each other and separated from each other by a central or intermediate section 3, in the form of a discharge casing ring 4 having a discharge or outlet passageway 5 therein, FIG. 1. The two end sections 2 and 2a are identical in construction to each other, except that they are mirror images to each other, and except that the drive shaft 6, which is common to both of the end sections 2 and 2a, has an end 7, which projects outwardly from the end section 2 for connection to a source of power, such as a suitable prime mover, not shown, for rotatably driving the drive shaft 6.

The end section 2 of the pump 1 includes an elongated casing section 8, FIGS. 1 and 2, which embodies an inlet casing ring 9, another casing ring 10, disposed in abutting, sealed relation to the inner side of the casing ring 9, and two other casing rings 11 and 12 disposed in spaced relation to the casing ring 10 and to each other; and an annular transfer plate 13 disposed between the casing rings 10 and 11 in sealed relation thereto, a second annular transfer plate 14 disposed between the casing rings 11 and 12 in sealed relation thereto, and a third annular transfer ring 15 disposed between the casing ring 12, of the casing section 8, and the adjacent discharge casing ring 4 in sealed relation thereto. The casing rings 4 and 9-12 and the transfer plates 13-15 are disposed in axially aligned relation to each other, and may be secured together by any suitable means, not shown, such as, for example, by bolts, as shown in my aforementioned U.S. Pat. No. 3,963,371.

The inlet casing ring 9 has an outer longitudinal end 16, with an inlet passageway 17 opening outwardly through the end 16 and extending inwardly therefrom to afford the inlet portion of a passageway which extends longitudinally through the section 2 of the pump 1, and is composed of the aforementioned passageway 17 through the casing ring 9, a passageway 18 through the casing ring 10, a passageway 19 through the transfer ring 13, a passageway 20 through the casing ring 11, a passageway 21 through the transfer ring 14, a passageway 22 through the casing ring 12, and a passageway 23 through the transfer ring 15, FIG. 2. The passageway 23, at the end thereof remote from the passageway 22, opens into the discharge outlet or passageway 5 in the casing ring 4 of the intermediate section 3 of the pump 1, FIG. 2. During operation of the pump 1, liquid, such as the aforementioned liquified gas or water, or the like, is fed through the passageway 17-23, into the discharge passageway 5 by a centrifugal impeller 24, mounted in the casing ring 10; a turbine impeller, mounted in the casing ring 11; and another turbine impeller 26 mounted in the casing ring 12, as will be discussed in greater detail presently.

The impellers 24-26 may be secured to the drive shaft 6 for rotation therewith in any suitable manner, but in the presently preferred form of the present invention preferably are keyed to the drive shaft 6 and secured thereon in the manner shown in FIG. 2, wherein the impeller 24 is secured between two lock collars 27 and 28, with a wavey spring washer 29 disposed between the lock collar 28 and the adjacent end of the hub 30 of the impeller 24, and with the inner face of the lock collar 28 disposed in abutting engagement with a locating snap-ring 31; the impeller 25 held between two generally annular liners 32 and 33 by a lock collar 34 and a snap-ring 35, with a wavey spring washer 36 disposed between the impeller 25 and the snap-ring 35; and the impeller 26 secured between two generally annular liners 37 and 38 by a lock collar 39 and a snap-ring 40, with a spring washer 41 disposed between the impeller 26 and the snap-ring 40. Seals 42 and 43, which may be of any suitable type, but, preferably, are of the type disclosed in my co-pending application for U.S. Letters Pat. Ser. No. 931,499, filed Aug. 7, 1978 and now issued as U.S. Pat. No. 4,173,350 are disposed around the shaft 6 within the transfer plates 14 and 15, respectively, for preventing or detering leakage of liquid axially of the shaft 6 through the transfer plates 14 and 15.

It is to be remembered that the pump 1 is intended to be adapted to pump liquids, such as, for example, liquified gases, at or near the boiling points thereof, as well as other liquids, such as, for example, water. To this end, the first stage of the multi-stage pump 1 or the preferred form of the present invention is a low pressure booster stage, embodying the centrifugal impeller 24 mounted in the casing ring 10, which, in operation, effectively lowers the low "net positive suction head" (N.P.S.H.) rating of section 2 of the pump in a manner similar to the centrifugal-impeller stage of the pump shown in my earlier U.S. Pat. No. 3,614,256. In the operation of the section 2 of the pump 1, the liquid enters the inlet entrance 17 and enters the centrifugal impeller 24 in the passageway 18 in the casing ring 10 and is discharged from the periphery of the impeller 24 through the passageway 19 in the transfer plate 13 into the passageway 20 of the casing ring 11 of the adjacent turbine stage, or second stage. The regenerative pumping action of the turbine impeller 25 builds up sufficient pressure to deliver the liquid through the passageway 21 in the transfer plate 14 into the passageway 22 in the casing ring 12 of the next adjacent turbine stage, or third stage. The regenerative pumping action of the turbine impeller 26 in the casing ring 12 builds up sufficient pressure to deliver the liquid through the passageway 23 in the transfer plate 15 into and through the discharge outlet 5 in the discharge casing ring 4, from which it is discharged outwardly from the pump 1. Preferably, each stage of the pump section 2 is balanced radially against its adjacent stage by placing the discharges of the successive stages at equal intervals around the shaft 6. It will be seen that, with this construction and mode of operation, the pump section 2 is effective to pump various liquids (whether they be in the form of liquified gases or in the form of water, or the like) from the inlet opening in the end 16 of the casing ring 9 through the passageway 17-23 in the casing section 8 and into and outwardly through the discharge passageway 5 in the discharge casing ring 4 of the intermediate section 3 of the pump 1.

The above described parts of the pump section 2 are identical in construction and mode of operation to corresponding parts in pump section 2a, except that they are mirror images thereof, and parts in pump section 2a which are the same as parts in pump section 2 are indicated by the same reference numerals with the suffix "a" added thereto. The one exception to the parts in pump sections 2 and 2a being identical to each other are the bearing assemblies 44 and 45 of the pump sections 2 and 2a, respectively, in which the drive shaft is rotatably mounted, and even these bearing assemblies 44 and 45 are preferably identical in construction, except that the end cap 46 of the bearing assembly 44 has an opening 47 therethrough, through which the drive shaft 6 projects for connection to a suitable prime mover, not shown, and the end cap 48 of the bearing assembly 45 is closed. The bearing assemblies 44 and 45 may be of any suitable construction, but preferably are of the same construction as the bearing assemblies shown in my aforementioned U.S. Pat. No. 3,963,371.

In the operation of the pump section 2a, liquid is fed from the inlet opening in the end 16a of the casing ring 19a through the passageway 17a-23a into and outwardly through the discharge passageway 5 in the discharge casing ring 4 of the intermediate section 3 of the pump 1 in the same manner as that described with respect to the feeding of liquid through the passageway 17-23 in the pump section 2 and outwardly through the discharge passageway 5 in the discharge casing ring 4. In this operation, liquid is fed inwardly through the inlet opening 16a and the passageway 17a in the casing ring 9a into the passageway 18a in the casing ring 10a, from which it is discharged by the impeller 24a through the passageway 19a in the transfer plate 13a into the passageway 20a in the casing ring 11a; is then fed by the impeller 25a through the passageway 21a in the transfer ring 14a into the passageway 22a in the casing ring 12a; and is then fed by the impeller 26a in the casing ring 12a through the passageway 23a in the transfer ring 15a into and outwardly through the passageway 5 in the discharge casing ring 4 of the intermediate section 3 of the pump 1.

From the foregoing, it will be seen that the casing rings 10-12 and 10a-12a, together with the parts operatively mounted therein afford individual, respective stages in the pump 1. Thus, the casing rings 10 and 10a, together with the impellers 24 and 24a mounted therein, respectively, each affords an individual, self-contained booster stage; and the casing rings 11, 12, 11a and 12a, together with the impellers 25, 26, 25a and 26a mounted therein, respectively, each affords an individual, self-contained regenerative turbine stage.

Also it will be seen that the corresponding stages in the oppositely disposed pump sections 2 and 2a are identical in construction so that the same identical parts may be used therein.

In addition, it will be seen that the pump 1 is of a modular-type of construction so that individual portions thereof, including complete stages may be readily removed and replaced or may be added to or eliminated from the pump 1. Thus, pumps having a greater or lesser number of stages than those shown in the drawings hereof may be produced without departing from the purview of the broader aspects of the present invention.

As will be appreciated by those skilled in the art, although the pump 1 is shown herein as embodying centrifugal impellers 24 and 24a, this is merely by way of illustration of the preferred form of the present invention and not by way of limitation, and where, for example, no low N.P.S.H. booster is needed, the centrifugal impellers 24 and 24a may be eliminated, such as, for example, by mounting the inlet casing rings 9 and 9a directly against the casing rings 11 and 11a, respectively, without departing from the purview of the broader aspects of the present invention.

If desired, a manifold, only two end portions 49 and 50 of which are shown in FIG. 1, may be connected to the pump 1, with the end portion 49 operatively connected to the end 16 of the casing ring 9, in communication with the inlet passageway 17, and with the end portion 50 operatively connected to the end 16a of the casing ring 9a, in communication with the inlet passageway 17a, for feeding the aforementioned liquid into both ends of the pump 1 from a common source, not shown.

When a single manifold is so used to feed both ends of the pump 1, it is often possible to use a manifold having a main feed line thereinto which is less than twice the size of the two inlet openings into the pump 1. For example, in many instances, a manifold, having a main feed line in the form of a pipe having a six inch diameter may be used to feed liquid into the two passageways 17 and 17a of the pump 1, wherein the inlet opening into the passageways 17 and 17a is four inches in diameter. This, of course, affords a saving in fittings, such as valves, and the like, the cost of such fittings for four inch pipes being substantially less than those for six inch pipes.

However, as will be appreciated by those skilled in the art, the reference to a manifold is merely by way of illustration and not by way of limitation, and the liquid may be fed into the passageways 17-23 and the passageways 17a-23a from respective individual sources without departing from the purview of the broader aspects of the present invention.

From the foregoing it will be seen that the present invention affords a novel multi-stage pump which has a capacity that is substantially double that of pumps of the one end suction-one end discharge type.

Also, it will be seen that the present invention affords a novel double-suction pump of the aforementioned type which has a novel modular construction, which enables the identical parts to be used in the two pump sections for affording the various corresponding, respective stages of the pump.

In addition, it will be seen that the present invention affords a novel pump of the aforementioned type wherein the bearings in the bearing housings 44 and 45 at both ends of the pump are subject to inlet pressure only.

Also, it will be seen that the present invention affords a novel pump of the aforementioned type which is practical and efficient in operation and which may be readily and economically produced commercially.

Thus, while I have illustrated and described the preferred embodiment of my invention, it is to be understood that this is capable of variation and modification, and I therefore do not wish to be limited to the precise details set forth, but desire to avail myself of such changes and alterations as fall within the purview of the following claims.