US1380798A - Pump - Google Patents

Description

G. T. HANSEN AND C. F. SHERWOOD. PUMP.

APPLICATION FILED APR. 28. 1919.

1,38QQ7Q8. Patented June 7 1921.

3 SHEETSSHEET I.

G. T. HANSEN AND 0. F. SHERWOOD.

PUMP.

APPLICATION FILED APR. 28,1919.

1,38@ ?98 Patented June 7, 1921.

3 SHEETSSHEET 2.

Q7 5 2/ it I .35 4? @Y: 7 2 I: I

5/ *f I L V [72067275715 @[IAQZSQE/ 5602 6 Tfiarzaezz I C/mfZcs FJ/zerwoad G. T. HANSEN AND C. F. SHERWOOD.

PUMP.

APPLICATION FILED APR. 28. 1919.

1,380,798, Patented June 7, 192i 3 sHEEIs-sHEET 3.

UNHT r rte GEORGE 'r. HAnsEirAnn CHARLES r, SHERWOOD, or saw LE CITY/UTAH.

PUBEP.

Specification of'Letters Patentah Patented June "Z, 1921.

Application filed, April as, 1919. Serial No. 293,295.

To all whom it may concern Be it known that we, GEORGE T. HAiNsEN and CHARLES F. SHERWOOD, both citizens of the United States, residing at Salt Lake City, in the county of Salt Lake and State of Utah, have invented a certain new and use ful Improvement in Pumps, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification. A

This invention relates to pumps.

The invention has particular reference to that class of pumps employed in pumping fluids containing gritty or abrasive material. Rotary sand pumps are exemplary of this class of pumps, or as affording a still better example of a pump to which the invention is particularly applicable, reference is made to the rotary pump used in pumping the tailings or gangue from ore separating apparatus. The tailings is the refuse left after the ore separating process has been completed and is usually composed of a suspension liquid such as water and.

. from their original shape and as the clearance areas between the impeller and the casing become enlarged through the abrasion of their surfaces. We have conceived that this difliculty could be overcome or greatly relieved by protecting or rendering more durable the exposed surfaces of the impeller element, as well as the exposed surfaces in the interior of the pump casing. Heretofore, it has been proposed to use metallic surfaces of hard metal, such as manganese steel. But such hard metal wears away rapidly. It has'also been proposed to use a resilient lining for the pump casing, preferably one of rubber, such as is disclosed in the patent to Jones, No. 888,814. This resilient lining has been attended with marked success, which may be explained by the fact that the rubber will yield at each point ofimpact before it will suffer abrasion by the impinging particles of ore. Neither of these methods, however, make any provision for the wear of the impeller member, the practice heretofore being to substitute a new impeller member for the worn one as often as necessary.

We have found that in the use of an ordinary metallic impeller with a rubber lined casing there is a tendency for particles caught at the edges ofthe impeller to tear the rubber, and also for the abrasive particles to become embedded in the rubber and score the unyielding metallic surface of the impeller.

To maintain the original shape of the impeller, to retain the original clearance, and v to prevent wear between the adjacent surfaces of the casing and impeller, we propose to applya resilient covering over the surface of the impeller, in addition to the resilient lining in the casing. We find that two resilient surfaces subject to the flow of an abrasive material between them will possess a "greater durability than two metallic surfaces, or one metallic surface and one resilient surface.

We have also devised an improved meth-.

od ofapplying the protective lining to the interior of the pump casing. This improved method holds the resilient lining securely in place and facilitates the insertion and removal of the lining.

In the accompanying drawings the invention is illustrated as applied to a tailin-gs pump of the type above described, though, as previously stated, the invention is broadly applicable to pumps in general for pumping fluids containing abrasive material. It will also be apparent that the invention may be advantageously adapted to the rotor or operating elements of difi'erent classes of machinery subject to erosion by abrasive materials, or subject to the impingement of fluids moving at high velocities.

In the drawings:

Figure l is a transverse sectional view through a rotary pump of the open'runner type illustratingthe application of the invention thereto;

Fig. 52 is an end elevational view of' the same with the front half of the casing removed;

Fig. 3 is an enlarged sectional view taken on the line 3-8 of Fig. 2;

Fig. 4 is an end elevational view of a rotary pump of the closed runner type;

Fig. 5 is a sectional view taken on the line .55 of Fig. 4:;

Fig. 7 is a view illustrating the manner of protecting the inlet conduit to the rotary pump and the exposed surfaces of the valve interposedin this conduit.

Referring first to the open runner type of pump illustrated in Figs. 1, 2 and 3, it will be noted that the metallic casing 2 of the pump is split intothe front and rear halves 3 and 4 respectively, which are joined by bolts 5 passing through bolting flanges 6 and 7 extending around the circumference of the casing section. The casing as a whole is supported upon a cylindrical shaft housing 8, to which the casing is bolted, as indicated, the housing 8 comprising part of a suitable pedestal bearing or the like, not shown. A bearing sleeve 9, in the cylindrical housing 8, affords abearing for the impeller shaft 10.

The front section 3 of the casing is provided with a central intake opening 11. A tailings pipe 12, leading from a separator box or other source, has communication with the central intake 11 through an elbow fitting 13 which is bolted-to the tailings conduit 12 and to the front casingsection 8. A discharge outlet 14: leads tangentially from the circular chamber in the interior of the casing 2, and has suitable connection with a discharge conduit 15.

The open runner or impeller, which is broadly designated 16, comprises a central hub 17 mounted on the driving shaft 10, and a series of impeller blades 21 radiating therefrom. The sectional formation of these impeller blades is illustrated in Fig. 3 and consists of a web portion 22 and a right angle flange 23 formed along the' trailing edge of the web portion 22, as shown in Fig. 2. These flanges form pockets on the intake side of the impeller blade 21, into which the pulp or tailings is delivered through the intake opening 11. The inner ends of the flan 'es 23 are chamfered off, as indicated, to fac1litate the flow of the pulp into these pockets. The centrifugal force created by the rotating impeller 16 will obviously impel the pulp outward into the annular passageway '24 from whence it will be discharged out through the discharge outlet 14.

The resilient lining which we employ for pretecting the'interior of the casing 2, is divided into two separate sections 25 and 26, each of these sections being preferably molded to conform to the interior surfaces of its respective casing section. These lining sections may be attached to the interior of the casing 2 by a clamping arrangement similar to that illustrated in the Jones patent hereinbefore mentioned, or by cementing to the surfaces of the casings, or by vulcanmemes izing directly to the metallic surfaces of the casings. A method which we find preferable to any of these, however, is that of applying the resilient lining to a thin metallic form or backing, which has been previously pressed into the shape of the casing, the combined lining, consisting of the ressed metallic form and the resilient linmg thereon, being then placed in the casing. These metallic forms are indicated at 27 and 28, and preferably consist of thin sheet steel plates which have been pressed into the conformation of their respective casing sections under a hydraulic press. A suitable grade of soft, tough rubber is the most desirable material for this resilient lining. The preferred method of securing the resilient lining to the sheet steel form is to first paint the surface of the form with a vulcaniz ing adhesive fluid and then vulcanize the rubber over this coating. The complete lining section is then fitted snugly into thev casing section where it is held by the bolting together ofthe two casing sections.

The protective rubber covering 30, which sheaths the surfaces of the impeller 16, may be applied in several ways. method is to place the impeller in a suitable mold and mold the rubber covering 30 upon the surfaces of the impeller. This method possesses the advantage of always applying the same thickness of rubber upon the impeller blades so that the calculated clearance between the impeller and easing lining will not vary. The rubber covering 30 is extended over the hub 17 and all surfaces of One preferred the impeller likely to be exposed to the abrasive action of the moving pulp. A vulcanizin liquid or the like may be used to assist in rmly securing the rubber covering 30 over the entire area of the impeller.

Practice has demonstrated that the amount ofabrasion which results from the impingement of the grit particles upon the resilient surfaces, or from their frictional wear in moving across these surfaces, is practically negligible as compared with that of the hard metallic surfaces. This is due to the elasticity of the layer of rubber, which will yield before it will suffer abrasion. It will be obvious from this action of the rubber surface that any particles of rock or quartz caught between the sides of the impeller and the interior of the casing will not score the surfaces but will be depressed into the yielding rubber until they can work out from between the impeller and easing.

Figs. 4:, 5 and 6 illustrate the invention as applied to a closed runner type of rotary pump. The general construction and operation of this type of pump is substantially the same as the pump just described. The pump casing 2 comprises the separable seccumferential bolting flanges 6 and 7. The

intake is through the elbow 13 and the dismanner as with the open runner type.

this case the elbow 13 is formed with an integral cover plate 32, which is bolted to a circular opening in. the front tion 3'.

The runner or impeller 33 comprises a pair of circular plates 34 and 35 spaced by a series of curved impeller blades 36. The blades36 project laterally from the face of the rear plate 34, with which they are formed integral. This rear plate 34 is rigidly mounted upon the impeller shaft 10' and is formed with a forwardly projecting hub 37. The ,front plate 35 is removable from the impeller and is normally secured casing secthe'reto by a spider or hollow hub 38, which projects back and is bolted to the end of'the boss 37. The front plate 35 has a central opening communicating with the passageway inthe elbow 13', andthe member 38 has radial openings 39, affording communica-.

tion between this opening and the interior of the impeller 33. Both plates 34 and 35 have openings 41 therein between the blades 36, for producing a circulation of fluid up.

through the clearance areas between the impeller 33 and the rubber lined casing 2.

The rubber liner sections 25 and 26 are constructed of the pressed steel form and layer of rubber vulcanized thereto, precisely the sameas hereinbefore described. The in-' ner surface of the front cover plate 32 has an individual rubber lining consisting of the layer of rubber 42 and the pressed steel form 43 which are extensive of the rubber liner 43 and steel form 42' in theelbow 13.

The entire surface of the plate 34 is sheathed with a protective layer of rubber 44, which extends out and also includes the surfaces of the impeller blades 36, asindi cated at 45 (Fig. 6). The front plate 35 is sheathed with an individual protective layer of rubber 46 so as to permit removal of this plate from the front of the impeller 33.

We also contemplate providing the intake conduit 12 and its .difierent fittings with our improved protective lining, as will be noted from Figs. 1 and.5. We find the use of this protective resilient lining to be of decided advantage for protecting the interior of the. conduits conveying the. tailings' to and from the pump, and particularly for protecting the interior of the conduit at bends and c1.- bows, and also the exposed surfaces of valves and other fittings in the conduits. In Fig. 7 we have illustrated this adaptation of our invention as applied to the intake conduit 12' leading to the" rotary pump just described. The conduit 12' is shown as comprising a plurality of conduit sections 50, preferably connected by bolting flanges, 51.

The interior of each conduit section is-fittedwith an individual rubber liner 52 vulcanized to a pressed steel form 53,so as to be readily removable from the conduit section? The elbow fitting 54 is similarly proyided with a rubber liner 5 5 backed bythe pressed steel form 56. It will be apparent that the outer curved surface in. the elbow' conduit 54 will be subject to a more severe abrasion from the impingement of the abrasive particles as they are deflected from one course of travel to another. To provide for the renewal of the resilient lining at. this point without the necessity of unbolting the elbow 54 from the rest of the conduit, we have provided a removable'plug 58, which seats in a boss 59 formed in the elbow 541 The plug is held in place by bolts 60engaging in cooperating flanges 61 and 62 on the plug 58 and boss 59. The inner end of the plug 58 is curved in conformation with the curved passage in the elbow 54 and is faced with a rubber facing 63 vulcanized directly tothe plug. The feature of applying a resilient pad or facing at the corner of a conduit conveying abrasive materials, is, we believe, broadly new. We contemplate the application of this idea to ash conveyers and the like.

We have illustrated a gate valve 65 interposed in the conduit 12 for throttling or completely stopping the intake flow of tailings to the pumpP. The closure surfaces of a valve interposed in a conduit conveying material of this character are usually sub-- ject'to a severe cutting by the impingement of the abrasive material, particularly when the valve member is in a throttlin position. We have remedied this condition%oy facing the closure surfaces of the valve member .with a resilient covering of rubber from which the impinging particles merely rebound. The valve gate 66 is of wedge for;

mation and is arranged to fit ina c0rresponding wedge seat provided in the conduit passageway. A screw 67 and hand wheel 68 are 'arrangedtoraise or lower the wedge gate 66in an obvious manner. Upon the wedge surfaces of the gate '66 we have applied a rubber facing or covering 69, which may be either vulcanizeddirectly to the gate or mounted upon a pressed steel backing which may be suitably secured to the gate. Theprotective covering 69 is extended around the side edges of the gate as well, and especially around the lower edges of the gate, which are particularly subject. to cuttin when the gate is in throttling position. he resiliency of the rubber facing on the valve gate will always insure a tight fit in the valve seat. j

The use of a resilient material for protecting the exposed metallic surfaces in the present invention, extends to all materials havingthe desired characteristics, such as leather, or a composition of rubber and fabric, or any other suitable material. Rubber is the preferred material, however, owing to its greater resiliency and to the low coefficient of friction between the water and the rubber when in a wet condition. The rubber, furthermore, protects the metallic surfaces of the pump and other lined parts against the corrosive action of the acids often contained in the tailings or refuse pulp.

It will also be apparent. that other methods of attaching the resilient material may be employed, such'as by cement or any suitable adhesive material.

We claim:

1. In a centrifugal pump for pumping a liquid containing abrasive material, a casing having an axial inlet and a peri heral outlet, said casing being divided on a p ane substantially at right angles to the axis of the pump, an impeller within the casing comprising a hub, a driving shaft secured to the hub, said impeller comprising a rigid flat portion lying, in a plane at substantiallyv right angles to "the axis of the shaft, and a plurality of rigidintegral flanges forming vanes and extendinggenerally radially and lying at right angles to the flat portion, said flat portion I and said flanges being completely coated with rubber secured perma-- nentl to the surfaces of the same and a remova 1e liner of rubber having a flexible sheet metal backing fittin the interior surfaces of said casing, said liner being divided on substantially the same plane as the casing, the partsof said liner being removable laterally from the interior of the casingfor repair or replacement, said impeller having its rigid portion lying between the two casing sections and partly in each.

2. In a centrifugal pump, a casing having an axial inlet, and a peripheral outlet, said casing being divided on a central plane substantially at right angles to the axis and having flanges for securing the two" parts together, a lining forthe interior of the pump comprising a relatively thin flexible sheet metal backing and a rubber facing, said lining covering substantially the entire interior surface of the pump casing and being divided on substantially the same plane as the casin and each half being capable of being with rawn laterally from the correr' sponding casin section.

3. In a centrlfugalpump, a snail shell casing hav ng an-axial inlet and a" tangential outlet, at lining for substantiallysthe entire inner surface of the casing, said casing being divided centrally on a plane at substantially right angles to the axis of the casing and said lining being divided into two parts on substantially the same plane, said lining comprising a thin sheet metal backing adapted to lie against the inside of the easing and a rubber facing each half of said lining having an axial tubular portion, one for an opening and the other for a shaft .the surface 0 aser/es opening, and each half having a tangential portion fittingthe tangential outlet of the casing, said halves of the lining being held together edge to edge by theclamping together of the casinghalves. I

4:. In a pump for pumping an abrasive material, the combination of a casing, an impeller .in said casing formed of a metallic wheel structure comprisin a hub, a plurality of metallic blades pro' ecting therefrom and having impelling surfaces, said metallic blades being formed integrally with said hub, a web construction joining said blades with said hub, and a continuous covering of rubber over the outer surfaces of said blades and over said web construction for preventing the abrasion or corrosion of the metallic structure thereof. v

5. Ina pump for pumping an abrasive material, the combination of a casing, a closed impeller in said casing comprising a rear, circular metallic plate, a hub formed on said plate for mounting the latter on a pump shaft,- a plurality of metallic impeller vanes formed integrally with said rear plate and projecting forwardly from the face thereof, a front circular metallic plate for closing off the open, side of said impeller vanes, said front plate having a central admission openingfor admitting the fluid to the vanes between said plates, screw means for fastening said front plate against said vanes, a protective covering of rubber molded over the exposed surfaces of said rear plate and said impeller vanes, and an independent protective covering of rubber molded over, the exposed surfaces of said front plate, said latter coverin being independent of the covering ofru her on said vanes and rear plate to permit removal of said front plate.

6. In a pump for pumping a fluid having an abrasive characteristic, a pump casing, said casing'being divided into sections, a protective lining in said casing, said lining being divided into sections fittlng into said casing sections, each sectionofsaid l1n1ngbe-- ing composed of athinsheet steel form pressed to conform to the interior of its c orresponding casing section, a rubber facing of relatively reater thickness vulcanized to I said form and exposed to the impingement of the abrasive material, said sheet steel form being sufficiently thin and ductile to permit of its being pressed into close engagement with the various surfaces of said pump casing. p In witness whereof I, GEORGE 'I. HANSEN, subscribe my name this 24th day of March,

CHARLES FJSHERWQOD.

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