US3155045A

US3155045A - Wear resistant pumps

Info

Publication number: US3155045A
Application number: US151616A
Authority: US
Inventors: George W Lown; Delmont D Brown
Original assignee: Individual
Current assignee: Individual
Priority date: 1961-11-13
Filing date: 1961-11-13
Publication date: 1964-11-03
Anticipated expiration: 1981-11-03

Description

Nov. 3, 1964 w. H. 'LOWN ETAL WEAR RESISTANT PUMPS 3 Sheets-Sheet 1 Filed NOV. 13, 1961 Illllll'lllllulllulll l.- I

ONN TWW mwm m IHD m 0 M L E WD .mm 1' Nov. 3, 1964 Filed Nov. 13, 1961 w. H. LOWN ETAL 3,155,045

WEAR RESISTANT PUMPS 3 Sheets-Sheet 2 mvamons:

WALTER H. LOWN DELMONT D. BROWN I BY 3 M x9: {pa/ 5 ATT'YS Nov. 3, 1964 w. H. LOWN ETAL 3,155,045

WEAR RESISTANT PUMPS Filed Nov. 13, 1961 s Sheets-Sheet 5 FIG. 6

INVENTORSZ WALTER H. LOWN DELMONT 0. BRbwN ATT'YS United States Patent "'ce 3,l55,tl45 WEAR RESTSTANT PUMPS Walter H. Lawn, 22tl9 Live Oak, San Angelo, Tern;

George W. Lawn, executor of said Walter H. Lown, de-

ceased, and Belmont D. Brown, 333 S. Main St., North Baltimore, Ohio Filed Nov. 13, 1961, Ser. No. 151,616 2 tClmms. (Cl. lll313) This invention, in general, relates to centrifugal pumps and, more particularly, to improvements in centrifugal pump construction for pumps which handle abrasive and corrosive fluids.

Fluids or viscous semi-fluids sometimes contain abrasive solids suspended in the liquid. These solids cause wear on all parts of a centrifugal pump in contact with the fluid, i.e., the impeller, the pumping chamber walls, etc. In fluids having a high abrasive solids content, metal parts of centrifugal pumps wear rapidly. The replacement of worn or abraded parts represents an expensive maintenance cost in operations in which these pumps handle large quantities of highly abrasive fluids. An example of such an operation is the pumping of return mud from oil or water drilling operations.

The improvements proposed by this invention relate to pump construction wherein the inside of the pumping chamber, the pump inlet and the pump outlet are lined with a replaceable, abrasion resistant liner made from a synthetic resin. Another feature of the invention is the impeller construction wherein the impeller is made of a metal backing plate covered with abrasion resistant synthetic resin and of impeller vanes having impelling surfaces which are abrasion resistant synthetic resin.

It is, accordingly, an object of the invention to provide improvements in centrifugal pump construction.

Another object is to provide a replaceable liner of synthetic resin for a pumping chamber.

Still another object is to provide improvements providing abrasion resistant impellers for centrifugal pumps.

These and other objects and advantages of the invention, which will be apparent to those familiar with centrifugal pumps, are attained by the utilization of the principles of the invention as herein described. An illustrative application of these principles to a specific embodiment of the invention is described hereinafter in conjunction with the drawings, wherein:

FIG. 1 is a side elevation of a centrifugal pump with the pumping chamber shown in cross-section and a section of the pump outlet broken away;

FIG. 2 is a side elevation of a metal backing plate used in the construction of centrifugal pump impellers of the invention;

FIG. 3 is an end elevation of the backing plate of FIG. 2;

FIG. 4 is a front elevation of an impeller of the invention in which the impeller backing plate is covered with abrasion resistant resin;

FIG. 5 is a diametric section, taken on section 5-5 of FIG. 4, of the impeller of FIG. 4; and

FIG. 6 is an end elevation of the centrifugal pump of FIG. 1.

The centrifugal pump in FIG. 1 comprises a frame 1 having a pair of upstanding saddles 2. and 3 supporting a cylindrical journal bearing 4. The bearing 4 rotatably journals the drive shaft 5 of the centrifugal pump impeller, which drive shaft is coupled to a drive motor or other suitable drive mechanism (not shown).

A pair of support plates 6 (one is shown in FIG. 1) are joined to the saddle plate 2 and the upstanding support plate 7 to form a rigid support for the pumping chamber 8. The pumping chamber is a cast, two-piece Patented Nov. 3, 1964 metal outer casing. The drive half 9 of the metal casing comprises a diec-shaped side wall ill, a cylindrical end wall lit and a flange 12. The disc-shaped Wall 1% has a central aperture 13 which is in line with the aperture 14 in the plate 7. The suction half 15 of the metal casing comprises a disc-shaped side wall 16, a cylindrical end wall 17 and a flange 18. The flanges 12 and 18 have a series of aligned bolt holes through which extend at spaced intervals bolts like bolts 1? with the nuts 20. The bolts and nuts hold the two halves together in the finished assembly. Welded to or cast as an integral part of the suction half 15 of the metal casing is a suction inlet sleeve 21.

A synthetic resin liner lines the interior of the pump chamber. The liner is made in two halves 22 and 23. The half 22 has a disc-shaped side wall 24, a cylindrical end wall 25 and a small, ring flange 26. it also has a hollow cylindrical segment 27 which is externally threaded at its outer end and has an outer diameter about the same size as the inside of sleeve 2 The half 22 of the liner is mounted in the suction half 15 of the metal casing by seating the liner half in the metal casing half, as shown, with the cylindrical segment 27 in sleeve 21. The liner half 22 is secured in the casing half 15 by threading the metal spanner lock nut 23 on the external threads provided at the outer end of the cylindrical segment 27. The sleeve 21 has an annular recess 28' at its outer end to accommodate the threading of spanner lock nut 28 on the external threads at the outer end of the cylindrical segment 27.

The liner half 23 comprises a disc-shaped side wall 29, a cylindrical end wall 3% and a small, ring flange 31. At the center of the disc-shaped Wall 29, there is an aperture from which projects outwardly a hollow, cylindrical sleeve 32.

The pump liner half 23 is mounted in the casing half 9 by seating the liner half in the casing half, as shown, with the cylindrical sleeve 32 projecting through the openings 13 and 14- of the wall 9 and plate 7, respectively. A lock nut 33, threaded on the external threads 34 of sleeve 32, holds the liner half 23 in place.

The sleeve 32 has an internal ring 35. The ring 35 forms inside the sleeve 32 a shoulder against which the packing 36 is seated when it is compressed by the end 37 of packing gland nut 38. This nut is friction-fitted in the sleeve 32 with its head against washer 39. This arrangement provides a fluid-tight assembly around the drive shaft 5, using a part of the liner half 23 to achieve the fluid-tight assembly.

When the pump is assembled with the impeller 40 (shown in phantom in FIG. 1) mounted on shaft 5 inside the pump chamber, the flanges 26 and 31 are squeezed together between the corner of the wall 17 and flange 18 and the corner of wall 11 and flange 12 to give a fluidtight joint between the liner halves 22 and 23. Fluid enters the pump chamber through the suction opening 41, is impelled outwardly by the impeller around the outside of the pumping chamber, and is discharged tangentially through the outlet 42.

The outlet 42 is situated on the rear side of the pump as viewed in FIG. 1. It is a vertical, tubular pipe 43 communicating with the pumping chamber. The tubular pipe 4-3 is made in two halves 44 and 45. Each half 44 and 45 is cast integrally with the pump casing halves 15 and 9, respectively. The tubular outlet pipe 43 is lined with the same abrasion resistant resin liner as the pumping chamber. The two

halves

46 and 47 of the pump outlet liner are molded as integral parts of liner halves 22 and 23, respectively. One semi-cylindrical outlet liner half 46 is seated in the tubular outlet pipe half 44. It has a small flange along each longitudinal edge of the semi-cylindrical half 46. The other outlet liner half is similarly a semicylindrical liner 47 seated in the outlet pipe half 45 and has a small flange along each longitudinal edge of the semicylindrical half 47. A flange along one edge of each of the outlet liner halves appears in FIG. 1, showing how the

liner flanges

43 and 4% are squeezed between the outlet casing flanges 5d and 51 to give a fluid-tight joint between the liner halves. The bolts and nuts in the flanges of the tubular outlet casing (similar to bolts and nuts 19 and 20) are not shown in FIG. 1.

The semi-cylindrical casing halves 44 and 45 each have half-ring flanges 52 at their upper ends. The flanges have bolt holes 54 for attaching a flanged pipe to the pump outlet. The half ring flanges 53 of the liner halves 22 and 23 seal the joint between the pump outlet and pipe. These flanges lie on the lips of the outlet pipe halves 4- and 4:3 to give a combination wherein the liner for the pump provide additionally a gasket seal between the pump outlet and the pipe connected thereto. The flange 5% with bolt holes 57 on the sleeve 21 provides means for attaching a flanged pipe to the pump inlet.

The pump impeller 48 is illustrated in detail in FIGS. 2-5. The impeller comprises a disc-shaped, metal backing plate 58 which has a plurality of spaced holes 5) therethrough. The plate 58 has on its rear face a hub es, in which the end of drive shaft 5 is tightly seated.

The front face of the backing plate 58 preferably, though not essentially, has a plurality of arcuate fins 61 extending outwardly from the front face and arcuately outwardly from the center area of the plate 58 to the edge thereof. The fins reinforce the impeller vanes which are hereafter described.

The entire surface of the impeller is covered with an abrasion resistant synthetic resin covering 62. This can be done conveniently by placing the impeller backing plate 58 in an impeller mold and injecting a moldable, abrasion resistant synthetic resin into the mold. The molded product is a metal-reinforced impeller in which all of the surfaces in contact with the fluid in the pump are covered with the abrasion resistant resin. FIGS. 4 and 5 show the resin covering 63 over the rear face of plate 53 and hub 60, which resin covering extends over the edge 6% into a covering 65 over the front face of the plate 58. The abrasion resistant resin also forms a covering 66 over the arcuate fins 61 to form the arcuate impeller vanes 67 of the pump rotor. The resin coverings 63 and 65 on the front and rear faces of the plate 5?, are connected by resin plugs 68 which extend through the holes 59 of plate 58 and aid in holding the coverings 53 and es on their respective plate faces. The fins 61 preferably are provided with similar holes 7t} through which similar resin plugs 71 extend to connect the covering 65 on the opposite faces of fins 61.

The abrasion resistant resin found most suitable for the practice of the invention is a polyalkylene ether polyurethane polymer. These polymers are obtained by reacting a polyalkylene ether glycol (preferably a polytetramethylene ether glycol) having a molecular weight of at least 750, an organic diisocyanate and a chain-extending compound containing active hydrogen atoms. The latter compound may be water or hydrogen sulfide or an organic compound containing active hydrogen atoms on two different atoms in the organic molecule.

The polyalkylene ether glycols are polyalkylene ethers containing terminal hydroxy groups. These compounds are ordinarily derived from the polymerization of cyclic others such as alkylene oxides or dioxolane or from the condensation of glycols. They are sometimes known as polyalkylene glycols, polyalkylene oxide glycols, polyglycols or polyoxyalkylene diols. They may be represented by the formula HO(RO),,H, in which R stands for an alkylene radical and n is an integer greater than 1. In the polyethers useful in this invention, It is sufiiciently large that the polyalkylene ether glycol has a molecular weight of at least 750. Not all the alkylene radicals present need be the same. Polyglycols formed by thecopolymerization of a mixture of different alkylene oxides or glycols may be used, or the polyglycol may be derived from a cyclic other such as dioxolane, which results in a product having the formula HO(CH OC H O),,H. The alkylene radicals may be straight-chain or may have a branched chain as in the compound known as polypropylene ether glycol.

Any of a wide variety of organic diisocyanates may be employed in the reaction, including aromatic, aliphatic and cycloaliphatic diisocyanates and combinations of these types. Representative compounds include 2,4-tolylene diisocyanate, m-phenylene diisocyanate, 4-chloro-l,3- phenylene diisocyanate, 4,4'-biphenylene diisocyanate, 1,5- naphthylene diisocyanate, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1,10-decamethylene diisocyanate, 1,4-cyclohexylene diisocyanate, 4,4-methylene bis (cyclohexyl isocyanate) and 1,5 tetrahydronaphthylene diisocyanate. Arylene diisocyanates, i.e., those in which each of the two isocyanate groups is attached directly to an aromatic ring, are preferred. In general they react more rapidly with the polyalkylene ether glycols than do the alkylene diisocyanates. Compounds such as 2,4-tolylene diisocyanate in which the two isocyanate groups differ in reactivity are particularly desirable. The diisocyanates may contain other substituents, although those which are free from reactive groups other than the two isocyanate groups are ordinarily preferred. In the case of the aromatic compounds, the isocyanate groups may be attached either to the same or to different rings.

The chain-extender is usually water although other chain-extenders of the type mentioned in US. Patent No. 2,929,800 may be used.

Another class of resins suitable for manufacture of the abrasion-resistant liners of the invention are the polyester urethane resins. These resins are produced by the reaction of organic diisocyanates with organic polyesters or organic polycarboxylic acids and polyhydric alcohols. Examples of said diisocyanates are hexamethylene diisocyanate and tolylene diisocyanate. The polycarboxylic acids may be adipic acid, phthalic acid, succinnic acid and the like. The polyhydric alcohols may be dihydric or trihydric alcohols such as ethylene glycol, diethylene glycol, butylene glycol-1,3, glycerol, trimethylolpropane and the like. The organic polyesters may be those prepared by condensation of the foregoing acids and alcohols or may be an alkyd resin. Furthermore, the resins may be produced from polyisocyanates or polythioisocyanates and amino alcohols and dicarboxy acids; glycols, diamines and dicarboxy acids; glycols, amino alcohols and dicarboxy acids; amino alcohols, diamines and dicarboxy acids; amino acids, amino alcohols and dicarboxy acids; glycols, dicarboxy acids and hydroxycarboxy acids; or amino alcohols, dicarboxy acids and hydroxycarboxy acids. These resins are described in US. Patent 2,333,639, the disclosure of which is incorporated herein by reference.

In the manufacture of the centrifugal pump of the invention, the liner halves 22 and 23 are molded separately, and the metal-reinforced impeller is molded separately. If desired, the metal fins 61 on the plate 58 may be omitted whereby the impeller vanes 57 consist of solid resin without reinforcement by metal. This construction, however, is less preferred from a strength viewpoint.

The pump components are then assembled to provide a centrifugal pump in which the pump components in contact with the fluid being pumped have abrasion resistant resin surfaces. The pumping chamber liner is readily replaceable when it becomes worn by a simple disassembling and reassembling of pumping chamber.

The pump casing may have a series of small holes 69 erein. These holes are known as weep holes and are provided in the casing so that water escaping from the pump liner due to wear of the liner or the like is detected readily. The liner then can be replaced before damaging Wear occurs on the metal casing.

The foregoing embodiment exemplifies the principles upon which the invention is founded. Other embodiments of the invention are readily derived by the application or these principles Without departing from the spirit and scope of the invention.

The invention is hereby claimed as follows:

1. A centrifugal pump for pumping abrasive and corrosive fluids comprising a pair of opposing, hollow, round, metal casing members forming a casing chamber of a centrifugal pump; a multi-vane, rotary, centrifugal pump impeller rotatably mounted in said casing chamber; a metal, cylindrical, pump inlet sleeve on one of said metal casing members and extending outwardly therefrom opposite the radial center portion of said impeller; a circular flange extending radially outwardly from the outer edge of said pump inlet sleeve, and adapted to be used to conple said sleeve to a flanged pipe; the other of said metal casing members having a hole opposite the radial center portion of said impeller; a semicylindrical, metal, pump outlet member on the radially outer portion of each of said casing members, said semicylindrical members being in opposing relationship and forming a cylindrical, casing passage directed tangentially with reference to said pumping chamber; a pair of opposing, round, hollow liners, each with a semicylindrical wall portion in opposing relationship to the other wall portion and directed tangentially from the radial outer portions and forming a cylindrical, fluid discharge, liner passage extending tangentially from the centrifugal pumping chamber formed by said opposing, round, hollow liners; a cylindrical sleeve liner extending outwardly from the radial center portion of a side of one of said round, hollow liners; said hollow liners being seated in said metal casing members, said semi-cylindrical wall portions being seated in said cylindrical casing passage, and said liner sleeve being seated in said metal, inlet sleeve; outwardly-directed flanges about the periphery of the opposing edges of said round, hollow liners and semicylindrical wall portions; means holding said metal casing members in rigid, opposing relationship; means on said metal casing members and said metal, se-micylindrical, pump outlet members pressing against said liner flanges and holding the liner flanges in abutting, fluid-tight contact; a second, hollow, sleeve projecting outwardly from said round, hollow liner through said hole in said casing member; said hollow liners, flanges thereon, said semicyclindrical wall portions, and said liner sleeve and second sleeve being made of an abrasion-resistant and corrosion-resistant synthetic resin selected from the group consisting of abrasion-resistant polyalkylene ether glycol-polyurethane resin and abrasion-resistnt polyester-urethane resin; an impeller drive shaft coupled to said impeller and extending through said second sleeve; packing means in said second sleeve providing a fluid-tight seal about said drive shaft; threads on the outer surface of said second sleeve, and a nut threaded on said threads and holding said liner on which said second sleeve is mounted in position in the corresponding metal casing member; said impeller covered by a coating of said synthetic resin; said metal, inlet sleeve having an annular recess in the radially inner part of the axial outer edge thereof; said cylindrical, liner sleeve having on the axial outer portion thereof threads on the radial outer side thereof, anda spanner loclc nut threaded on said last-mentioned threads tightly against said metal inlet sleeve in said recess to hold said hollow liner on which said liner sleeve is located in the corresponding metal casing member; said spanner lock nut having an axial thickness less than the axial depth of said recess whereby said spanner lock nut is recessed relative to the axial outer face of said flange on said metal inlet sleeve.

2. The centrifugal pump as claimed in claim 1 wherein said rotary impeller comprises a metal backing plate with a plurality of holes therethrough; a plurality of metal fins proiecting from one face of said backing plate; said synthetic resin covering selected from the group consisting of abrasion-resistant polyalkylene ether glycol-polyurethane resin and abrasion-resistant polyester-urethane resin molded over both faces of said plate and over said fins; the synthetic resin covering over said fins being shaped to form impeller vanes; and plugs of said synthetic resin extending through said holes in said plate to aid in holding the resin coverings on said faces (if said plate.

References Cited in the file of this patent UNITED STATES PATENTS 1,249,572 Weitling Dec. 11, 1917 1,254,156 Parsons Jan. 22, 1918 1,850,683 Merrill Mar. 22, 1932 2,110,079 Butler Mar. 1, 1938 2,333,639 Christ et a1. Nov. 9, 1943 2,729,618 Muller Jan. 3, 1956 2,929,800 Hill Mar. 22, 1960 FOREIGN PATENTS 102,859 Australia Aug. 17, 1939 199,250 Great Britain June 21, 1923 373,727 Great Britain June 2, 1932 625,898 Great Britain July 6, 1949 520,558 taly Mar. 22, 1955 OTHER REFERENCES Publication: Otlicial Digest, September 1959, The Properties and Application of Urethane Coatings, by Edward R. Wells, George A. Hudson, Dr. James H. Saunders, and Dr. Edgar E. Hardy, Mobay Chemical Co. (pages 1181-1210).

Publication: Polyurethanes, Reinhold Plastics Application Series, by Bernard A. Dombrow (166 pages).

Claims

1. A CENTRIFUGAL PUMP FOR PUMPING ABRASIVE AND CORROSIVE FLUIDS COMPRISING A PAIR OF OPPOSING, HOLLOW, ROUND, METAL CASING MEMBERS FORMING A CASING CHAMBER OF A CENTRIFUGAL PUMP; A MULTI-VANE, ROTARY, CENTRIFUGAL PUMP IMPELLER ROTATABLY MOUNTED IN SAID CASING CHAMBER; A METAL, CYLINDRICAL, PUMP INLET SLEEVE ON ONE OF SAID METAL CASING MEMBERS AND EXTENDING OUTWARDLY THEREFROM OPPOSITE THE RADIAL CENTER PORTION OF SAID IMPELLER; A CIRCULAR FLANGE EXTENDING RADIALLY OUTWARDLY FROM THE OUTER EDGE OF SAID PUMP INLET SLEEVE, AND ADAPTED TO BE USED TO COUPLE SAID SLEEVE TO A FLANGED PIPE; THE OTHER OF SAID METAL CASING MEMBERS HAVING A HOLE OPPOSITE THE RADIAL CENTER PORTION OF SAID IMPELLER; A SEMICYLINDRICAL, METAL, PUMP OUTLET MEMBER ON THE RADIALLY OUTER PORTION OF EACH OF SAID CASING MEMBERS, SAID SEMICYLINDRICAL MEMBERS BEING IN OPPOSING RELATIONSHIP AND FORMING A CYLINDRICAL, CASING PASSAGE DIRECTED TANGENTIALLY WITH REFERENCE TO SAID PUMPING CHAMBER; A PAIR OF OPPOSING, ROUND, HOLLOW LINERS, EACH WITH A SEMICYLINDRICAL WALL PORTION IN OPPOSING RELATIONSHIP TO THE OTHER WALL PORTION AND DIRECTED TANGENTIALLY FROM THE RADIAL OUTER PORTIONS AND FORMING A CYLINDRICAL, FLUID DISCHARGE, LINER PASSAGE EXTENDING TANGENTIALLY FROM THE CENTRIFUGAL PUMPING CHAMBER FORMED BY SAID OPPOSING, ROUND, HOLLOW LINERS; A CYLINDRICAL SLEEVE LINER EXTENDING OUTWARDLY FROM THE RADIAL CENTER PORTION OF A SIDE OF ONE SAID ROUND, HOLLOW LINERS; SAID HOLLOW LINERS BEING SEATED IN SAID METAL CASING MEMBERS, SAID SEMI-CYLINDRICAL WALL PORTIONS BEING SEATED IN SAID CYLINDRICAL CASING PASSAGE, AND SAID LINER SLEEVE BEING SEATED IN SAID METAL, INLET SLEEVE; OUTWARDLY-DIRECTED FLANGES ABOUT THE PERIPHERY OF THE OPPOSING EDGES OF SAID ROUND, HOLLOW LINERS AND SEMICYLINDRICAL WALL PORTIONS; MEANS HOLDING SAID METAL CASING MEMBERS IN RIGID, OPPOSING RELATIONSHIP; MEANS ON SAID METAL CASING MEMBERS AND SAID METAL, SEMICYLINDRICAL, PUMP OUTLET MEMBERS PRESSING AGAINST SAID LINER FLANGES AND HOLDING THE LINER FLANGES IN ABUTTING, FLUID-TIGHT CONTACT; A SECOND, HOLLOW, SLEEVE PROJECTING OUTWARDLY FROM SAID ROUND, HOLLOW LINER