US3556685A

US3556685A - Buoyant pump with drive train subassembly

Info

Publication number: US3556685A
Application number: US794743*A
Authority: US
Inventors: Frederick A Moore
Original assignee: Northwest Industries Ltd
Current assignee: Northwest Industries Ltd
Priority date: 1968-11-29
Filing date: 1969-01-28
Publication date: 1971-01-19
Anticipated expiration: 1988-01-19

Abstract

THE IMPELLER CHAMBER BACKING WALL, FORMERLY AN INWARD EXTENSION OF THE VOLUTE IS CUT AWAY AND A DETACHABLE METAL PLATE SUBSTITUTED, THUS THE IMPELLER, SHAFT, BEARINGS AND SEAL MAY BE WITHDRAWN TOGETHER WITH THE CHAMBER WALL. THE WALL IS DISHED TO FORM AN OIL SUMP SO AS TO ACCOMMODATE A SPEED REDUCER, A SUMP COVER PLATE PROVIDES LOCATIONS FOR MOUNTING THE POWER UNIT.

Description

Jan. 19, 1971 v F. A. MOORE 3,555,535

BUOYANT PUMP WITH DRIVE TRAIN SUBASSEMBLY Filed Jan. 28, 1969 2 Sheets-Sheet 1 IN VENTDR FREDERICK R- NDORE HTTORNEyS Jan. 19, 1971 F, A, MOORE 3,555,555

BUOYANT PUMP WITH DRIVE TEA IN SUBASSEMBLY Filed Jan. 28, 1969 2 Sheets-Sheet I I/VVEA/ TOR FRBDEIZ/dr n- NOD/YE HTI'DRIVEyS U.S. Cl. 417-337 United States Patent 3,556,685 BUOYANT PUMP WITH DRIVE TRAIN SUBASSEMBLY Frederick A. Moore, Edmonton, Alberta, Canada, as-

signor to Northwest Industries Limited, Edmonton, Alberta, Canada Filed Jan. 28, 1969, Ser. No. 794,743 Claims priority, application Canada, Nov. 29, 1968,

Int. Cl. F04d 13/02, 13/14 8 Claims ABSTRACT OF THE DISCLOSURE The impeller chamber backing wall, formerly an inward extension of the volute is cut away and a detachable metal plate substituted; thus the impeller, shaft, bearings and seal may be withdrawn together with the chamber wall. The wall is dished to form an oil sump so as to accommodate a speed reducer; a sump cover plate provides locations for mounting the power unit.

This invention relates to the general field of buoyant centrifugal pumps and specifically to the problem servicing the drive train; more narrowly it relates to the problem of making a seal in such pumps which will prevent leakage of water into the speed reduction assembly.

In one commercially successful buoyant pump the housing comprises a squat three component structure of thin lightweight material such as moulded glass reinforced polyester sheet. The upper and middle components are contoured to form a buoyancy chamber, the middle component being reentrant within the buoyancy chamber to form the upper portion of the pump volute. The lower component of the housing forms the lower portion of the pump volute, as well as the lower wall of the impeller chamber and the inlet to the impeller eye. Such features are common to the present invention although not of direct concern and are further described later below.

In the prior art, however, the upper and middle moulded sheet components continued separately inwards to a diameter where they were moulded to a stiff cylindrical glass polyester support surrounding a central metal sleeve. This sleeve was thus integrally moulded into the assembly of the upper and middle housing pieces and was pro- 'vided with a bearing surface for the impeller shaft, and lands for retaining shaft seals. The middle moulded sheet piece between the volute chamber and the metal sleeve was substantially flat to form the impeller chamber upper wall; the upper piece was formed as a shallow dish to accommodate a speed reduction train between the impeller and an internal combustion engine drive shaft.

Unfortunately, such an assembly was awkward to service requiring impeller removal before the shaft could be extracted upwardly from the housing. Thus, servicing often required return of the whole pump as field service of a drive train component could not be carried out by a replacement drive train.

Moreover, leakage occurred, not through the shaft-tosleeve seals, but between the metal sleeve and the cylindrical polyester surround necessitating relatively frequent service. This may have been due to rough handling or extreme fluctuation in temperature, as by immersion of a warm pump in ice cold water; whatever the cause, water leaked into the speed reduction train displacing the oil and damaging components so as to destroy the drive.

I have discovered that the disadvantages of the prior art pump housing and drive arrangement are overcome by terminating both upper and middle moulded housing sheets at a radius greater than that of the impeller and smaller than the volute. This permits the bearing sleeve Patented Jan. 19, 1971 to be welded integral :with a support cone which is then secured to the top of the upper housing piece. This also permits a second development-that of making the shaft, impeller, sleeve, speed reduction train, and its dish and cover as a unitary subassembly. Yet another feature over the prior art permitted by the excision of the central portion of the upper and middle housing pieces is that the impeller shaft can be provided with an upper bearing to steady it. Yet other unobvious steps will become apparent on perusal of the description below and the claims.

The invention will be more clearly understood by reference to the drawings in which:

FIG. 1 shows an informative cross section of the pump, and

FIG. 2 shows an oil supply arrangement for one of the pump gears.

In FIG. 1, 2 is the upper structural component of thin sheet material which, with the contoured middle component 4, forms a buoyancy member 6. Buoyancy member 6 is filled with cellular lightweight expanded foam. Handles 7 are fitted to facilitate carrying the pump, A lower component 8 also formed from thin sheet stock is contoured so as to cooperate with middle piece 4 to form a volute chamber 10, for the pump impeller 12. This lower component extends inwardly as in the prior art to form a lower impeller chamber wall 14 Which is faired downwardly to provide a central inlet 16 to the eye of the impeller. The outlet from the volute is not shown in this section. It will be understood that by such terms as volute chamber diameter, I would refer to the roughly circular cross section of 10, and by volute diameter I can a dimension in the plane of the impeller 12.

A moulded base 18 having a series of holes 20 and integral stiffening channel ribs 22 is bolted to the squat three component structure by self-tapping screws 23 and allows free access of the fluid to be pumped to the central inlet 16. This base protects the inlet from blockage by mud or damage by stones when the fluid level falls so that the pump is aground, and two sections are shown to assist understanding. It will be understood that the selftapping screws, 23, are in fact held by rectangular steel inserts 24 which are trapped between the flat flange of item 4 and a local overmoulding 25 of polyester resin reinforced by chopped glass roving.

Contrary to the teachings of the prior art, upper and middle formed sheet pieces 2 and 4 terminate inwardly at 26 which corresponds to a diameter slightly greater than that of the pump impeller in a bonded joint, 28. Preferably this bonded joint is made from catalysed polyester resin filled with long glass fibre and thixotropic silica to form a cement.

An integral assembly of a speed reduction mechanism, casing, shaft and impeller indicated generally at 30 is bolted to the upper thin structural piece 2 by self-tapping screws 31. Again, these screws are, in fact, held by rectangular steel inserts 32 trapped between the glass polyester casing 2 and a local overmoulding 33.

This integral assembly comprises a hollow inverted generally conical sheet metal member 34 and sleeve 36. I call sheet metal member 34 a wall means because it provides the impeller chamber upper wall as well as the sump lower wall. These items are welded together to provide a completely leak-proof joint, the assembly being termed a sump for reasons given later below. The shape of member 34 is not critical, but I have had good results with the contour shown which permits good upper and lower sealing welds and represents a good compromise in limited space. For reasons of lightness, corrosion resistance, relative cheapness and ease of welding and working, the obvious material choice for the sump 34, 36 is aluminum although other materials may be used.

This sump 34, 36 is covered by a cast aluminum plate 38 called an engine mounting plate, a sealing gasket 39 being trapped between them. Set screws hold the sump and plate together to form an enclosure for a speed reduction drive. Although I have chosen to use a gear reduction, and certain features of the particular gear reduction are unobvious, it will be apparent to those skilled in the art that other types of speed reducers, such as a chain and sprocket drive could be accommodated in the enclosure.

An engine, which has mounting feet 42 is fastened to bosses 44 of the engine mounting plate 38 by bolting, 46, 48. The bosses have holes with sufficient clearance to allow accurate location of engine shaft 50. The engine is not shown in full; I prefer to use a four cycle air cooled engine Tecumseh (Tecumseh is a trademark) model LAV 35 which has a rating of 3.5 horsepower at 3,600 r.p.m. but other suitable sizes and types of engine or motor may be used, as desired.

This engine shaft passes through an oilite bushing 52 in the engine mounting plate 38 and drives a pinion gear 54 through a Woodrutf key 56. The pinion 54 incorporates a retaining ring 58 which enables it to be fastened to engine shaft 50 by means of a ca screw 60 and accompanying washers and lock washers. Seepage of water down the shaft is prevented by O-ring 62 which is trapped between the upper surface of double sided boss 64 for the engine drive bush and the engine shaft spigot land 66.

Pinion gear 54 drives internal annular gear wheel 68 which generally resembles a shallow cup. This gear wheel 68 is of aluminum cast in a permanent mould about steel hub 67, which is machined to be a press fit on impeller shaft 70, extraction holes 69 being provided to facilitate removal. Impeller shaft 70 is held between plain journal bearing 72 in sleeve 36 and an oilite bush 74 in bOSs 76 on engine mounting plate 38. It will be readily understood that the holes for bush 52 and 74 may be jig drilled together so as to ensure accurate mating for the teeth of pinion 54, and internal gear 68. It will also be understood that the section of FIG. 1 has been chosen to give as much information as possible and is not across a diameter as indicated by the broken sections.

A feature of internal annular gear 68 is that oil for t e teeth surfaces is provided by a tube 78 projecting into the oil sump as shown in FIG. 2. Tube 78 is chamfered at both ends at an angle of 45 to the axis, the planes of each chamfer being at 45 to each other; this tube is set into a hole drilled at 45 to the bottom inside surface of the internal gear 58. The axis of the hole is such that it is substantially tangential to the circle of rotation of the open end of the tube; thus, as the gear rotates the ch mfered end is vertically disposed and scoops up oil. The other end, lying flat on the bottom inside surface of the gear 68 allows the oil to flow over the bottom surface and up the gear teeth by centrifugal force. Arrows entering and leaving tube 78 in FIG. 2 illustrate the oil flow. I find diameter aluminum tubing set at a radius of 1%," from the centreline when the reduction ratio is 50:13 provides good lubrication without flooding and consequent churning and aeration of the oil. The unnumbered diametrically opposed A hole balances the gear.

Thus the oil is not required to fill the enclosure in order to lubricate the teeth; the oil level in the sump need only be such that tube 78 is below its surface at all times, it being understood that the oil within the cup of gear 68 is not level but has the surface of a paraboloid of revolution which feeds oil to the gear tooth faces.

The last feature of major interest is the combined dipstick and vent which comprises a hollow copper tube 78 soldered into a brass pipe plug 80 which is drilled with a through hole to accept the tube. The tube is crimped together at the top to prevent entry of water; two diametrically opposed 1 diameter holes, 82, through the tube wall allow adequate venting with good free board in case of ch PPY water.- TQ check oil level the plug is un- 4 screwed and inverted so that vent tube 82 reaches into the enclosure and becomes a dipstick registering the level of oil in the sump.

The remainder of the structure is straight forward. Oil is drained from the sump by removing plug 84 from tapped hole 86 and tilting the assembly on its side. Stepped lands 88 and 90 in sleeve 36 accommodate a radial and an axial seal 92, 94 respectively, the latter bearing on the end of the hub 96 of impeller 12.

The function of the pump also needs little descriptionit will be noted that during operation the space between the sump 34, 36 and the upper surface of the impeller 12 fills with water to a greater or lesser extent. For this reason the upper and middle casing members have been enlarged over the prior art to provide greater floatation and to accommodate a greater proportion of the volute chamber.

It will be understood that although the construction has been explained in some detail, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention as defined by the appended claims.

I claim:

1. A buoyant centrifugal pump comprising:

a generally annular buoyancy member having a reentrancy on the lower surface, the reentrancy being in the form of a portion of a centrifugal pump volute chamber and of a portion of the outlet therefrom, the buoyancy member terminating inwardly at a diameter adjacent the volute inner diameter,

a lightweight sheet material member fastened on the underside of the buoyancy member and having such a shape as to form a pump inlet,

a lower impeller chamber wall, the remainder of the volute chamber and the outlet therefrom,

a wall means detachably mounted on the upper side of the buoyancy member and extending inwardly therefrom towards the impeller shaft so as to provide an impeller chamber upper wall with a central hole therethrough,

an impeller having a maximum diameter smaller than the inner terminating diameter of the buoyancy member, the impeller being located between the impeller chamber lower and upper walls,

an impeller shaft extending through the central hole of the impeller chamber upper wall, and

a power source above the impeller chamber upper wall suitably connected to the impeller shaft.

2. A buoyant centrifugal pump as claimed in claim 1 wherein the impeller chamber upper wall means is downwardly dished and further comprises an integral bearing sleeve and a seal for the impeller shaft, the downward dishing of the impeller chamber upper wall me ns providing an oil sump thereabove.

3. A buoyant centrifugal pump comprising:

a lightweight sheet material member fastened on the underside of the buoyancy member and having such a shape as to form a pump inlet, a lower impeller chamber wall, the remainder of the volute chamber and the outlet therefrom,

a wall means detachably mounted on the upper side of the buoyancy member, the wall means being dished inwardly and downwardly and having an integral bearing sleeve and a seal so that the wall means provides both an impeller chamber upper wall at the under surface and an oil sump at the upper surface,

an impeller shaft extending through the bearing sleeve in the impeller chamber upper wall into the oil sump provided thereby,

an engine mounting plate cooperating with said Wall means so as to cover the sump and thus provide an enclosure therewith,

a speed reduction device accommodated in said enclosure between said wall means and said engine mounting plate, and

an internal combustion engine mounted upon said engine mounting plate, the drive shaft of the internal combustion engine being connected so as to drive the speed reduction device, and the speed reduction device being connected to drive the impeller shaft.

4. A buoyant centrifugal pump as claimed in claim 3 wherein the drive shaft from the internal combustion engine extends through the engine mounting plate and said speed reduction device comprises a gear mounted on such drive shaft extension and a gear on the impeller shaft in direct engagement with the engine drive shaft gear.

5. A buoyant centrifugal pump comprising:

an internal combustion engine mounted upon said engine mounting plate, the drive shaft of the internal mounting plate, and

a speed reduction device accommodated in said enclosure comprising a high speed pinion gear on the engine drive shaft and an internal annular gear mounted on the impeller shaft and in driven relationship with the high speed pinion gear.

6. A buoyant centrifugal pump as claimed in claim 5 in which the internal annular gear has a web connecting the hub to the teeth, and further comprises an oil scoop means adapted, upon rotation of the internal annular gear, to gather oil from the sump and to deliver oil to the internal teeth.

7. A buoyant centrifugal pump as claimed in claim 6 in which the scoop means is an inclined tube.

8. A buoyant centrifugal pump as claimed in claim 3 and further comprising a combined vent and oil dipstick which include:

a hollow plug releasably blocking a through hole in the engine mounting plate, and

a hollow tube integral with said plug and closed at the upper end, said hollow tube having a substantial length relative to the dimension of the engine mounting plate hole and having at least one hole through the tube wall at the end distal from the plug, the tube Wall hole being of such a diameter as to inhibit the admission of water.

References Cited UNITED STATES PATENTS 3,397,647 8/1968 Daniel 103218 3,461,807 8/1969 Morrison 103103 ROBERT M. WALKER, Primary Examiner