US2090162A - Pump and method of making the same - Google Patents

Description

G. C. TIGHE PUMP AND METHOD OF MAKING THE SAME Filed Sepl'n/y l2, 1954 Aug. 17, 1937.

Patented Aeg. 17,v 1937 UNITED STATES A 2,090,162 PATENT OFFICE l PUMP AND IVIETHD OF MAKING THE SAME George C. Tighe, Detroit, Mich., as'signor, by mesne assignments, to Rustless Iron and Steel Corporation o! America, a. corporation of Dela- Ware Application September 12, 1934, Serial No. 743,773

7 Claims.

. This invention relates to fluid pumps and more particularly to hydraulic pumps, especially of the centrifugal type.

One of the objects of my invention is the provision of a fluid pump which has a minimum of wear, corrosion and erosion of moving parts and which requires a minimum of adjustment and/or shut-down and repair.

Another object is the provision of a pump `0 adapted for use in circulating water in the cooling system associated with an internal combustion engine, such as the cooling systems associated with the engines of automotive vehicles, that is highly efficient and less given to leakage than .5 heretofore known and/or used pumps of the character indicated throughout the long periods of alternate use and idleness, the various soft and hard waters employed as cooling ulds, and

the dirt, grime, heat and vibration encounteredV l0 in actual, practical use.

A still further object of my invention is the provision in a simple, direct, eilicient, and thoroughly reliable manner of a pump Yshaft well adapted to withstand the varying conditions encountered in use. Y A

Other objects of my invention in part will be obvious and in part pointed outhereinafter.

The invention, accordingly, consists in the combination of elements, features' of construction and arrangement of parts and in the several method steps and the relation of each offthe 'same to one or more of the others as described' herein the scope of the application of which is indicated in the following claims.

parts of whichiare broken away to more clearly disclose certain' features of my invention, to-

gether with associated driving'-means and auxil 40 iary mechanism.

As conducive to a Yclearer understanding, of certain features Yof my invention it may be noted atthis point that in many branches of industry, agriculture, mining and the like iluids are conline or salty in character or which may contain a considerablev proportion of dirt, gritl or other further noted that in all of the In the accompanying. drawing, illustrative of" my invention, there is Ashown a,`pump,-certa.ln

veyed or handled which may be either acid, alka pumps employed for handling uids ofthe character indicated there are a number of intricate mechanical parts of special shape requiring considerable accurate machining. The pump shafts or members actuating the moving parts of the various pumps reguire an especially great amount of machining, as inthe provision of precise bear# ing surfaces, grooves, slots, threaded end-sections and drilled portions, which greatly contribute to the expense of producing the pumps.

` In heretofore known and/or used pumps of the general character indicated the use of corrosiony resistant and wear-resistant movingparts, and

more particularly the use of corrosion-resistant and wear-resistant pump shafts, renders the pumps prohibitively expensive for use in generalY applications where mildly corrosive and/or erosive conditions are encountered because of the proportionately greater expense of these materials over the materials commonly used in general duty pumps and because of the increased cost of machining Vand iinishing this vwear-resistant metal. Where the general duty pump is employed in this class of service, as for example in circulating cooling water employed in the cooling sys- 1 tems associated with internal combustion engines, driving automotive vehicles, the grit and dirt present in these waters and especially the oxide scalecoming'rfrom theY cooling jackets of the enginel are all effective in causing considerable wear of the pump shaft by corrosion and erosion. point where the pump shaft passes through the pump housing and where the pumpis packed to avoid leakage at these points. Under theconditions encountered in actual, practical use. where long periods of idleness are succeeded'by long periods of operation the pump shaft is especially V- corroded at Athese sections. i

While theprecise nature of this corrosive attack'is, not denitely known it is variously at''" tributed to corrosionV of the metal by air dissolved in the water 'or to a direct' chemical attack of the metal by the acid or alkaline content of the water, such as carbonio acid result- This wear is especially greatat the ing from the water dissolving Acarbon dioxide present in the gases exhausted from the'engine,

or to an electro-chemical action arising from inherent f differences in v the Yelectro-,potentials of the metalsl employed in the pump construction in and adjacent to themoving parts (the cast iron or cast steel of the pump housing. themild steel of the pump shaftand'the'bronze or brass of the packing nuts employed tomaintain Vthe pump packing in proper position forming withV the fluid handled by the pump an electrolytic cell eilecting corrosion ofthe pump shaft); This corrosion, however produced, is effective in lforining on the surface of the shaft afthin corrosion product which is subsequently worn away by the l shoulder I5d of the shaft'.

`screw (not shown) abrasion or erosion encountered in operation of the pump, permitting the formation of a new corrosion product which isrsubsequently worn away, an action which continues during the normal operation of the pump shortly causing an objectionable leakage of the pump at these points. 'I'he continual adjustment or tightening of the pump packing in an attempt to stop the leakage in many instances causes-a binding of the pump land a scouring jof the pump shaft resulting in further and greater leakage. The continual adjustment, repair and replacement of parts necessary to prevent leakage of the pump, and loss'of cooling fluid in an internal combustion engine for example, is not only expensive in labor and materials but also causes many highly objectionable delays in the use and operation of the auto 'finished to desired specifications at minimum expense.

'Referring now more particularly to the practice of my invention attention is directed to the drawing wherein a centrifugal pump generally indicated at I0 is suitably mounted adjacent an internal combustion engine (not shown) as by being' bolted to the gear casing of the engine as generally indicated at II with a suitable gasket intervening. Illustratively, pump I0 comprises a section of pumpl housing I2, conveniently of cast steel, shaped to include a bearing housing vportion I 2a and support bracket I2bf which is conveniently bolted to the gear housing of the internal combustion engine. The pump housing is completed by a second portion I3, conveniently of cast steel, which is conveniently fastened to the portion I 2 by bolts I4. 'To give a water-tight chamber the two parts of the pump housing are separated by a gasket in accordance with established practice.

Journaled within bearing housing I2a is pump shaft I'5 which passes through drilled and threaded end-portions I2c and I3a of pump housing I.2-'I3. Mounted on shaft I5 and maintained properly spaced within pump housing I 2-I3is the pump impeller I6 conveniently slotted as'at Ilia and fastened to shaft I 5 by key I1 interfitting a suitable key-Way provided in the shaft.

'I'he shaft I5 is rotatably mounted and maintained in axial alignment with pump housing I2-I3 by means of a Babbitt sleeve Ibearing I8 snugly interlitting the hole portion I2d provided in the bearing housing to which the sleeve bearing is secured in any suitable manner, as by a set Power is supplied shaft I5 by way of gear I0 mounted' on a constructed endportion I5b of the shaft and conveniently fastened thereto by key 20 intertting a slotted portion of the shaft and a slotted portion I9a of the gear. Movement along the length of the shaft is effectively precluded by the castellated nut 2| engaging a threaded portion I5c' of the shaft forcing an inner shoulder I9b of the gear against Loosening of the nut is prevented by the cotter key 22 passing through a hole I5e provided in the end of the'shaft and resting snugly within the crenellated portion 2 Ia nf the nut.v

End-play of shaft I 5 is effectively precluded by lthe faceISc of driving gear I9 encountering an end-portion I8a ofthe sleeve bearing which prevents motion of theshaft from right to left, as seen in the drawing. Motion of the shaft in the direction from left to right is prevented by fashioning the shaft with an integral collar portion I5f which encounters the end-portion Ib of the sleeve bearing.

lIt may be noted at this point that' because of the considerable amount of machining -of the pump shaft necessary to provide a good bearing surface, grooves, key-ways, threaded end-portions and the like, a material which is strong and tough and` yet which may be readily machined is desired. The well known cold rolled mild steel or special alloy steels containing small percentages of chromium, vanadium, copper, silicon and the like ,give good results.

As driving energy is supplied the shaft I5 the shaft revolves the pump and impeller I6 causing a flow of cooling fluid in through pump intake I2e Where it is directed radially toward the shaft by the peculiar shaping of pump housing I2.

The cooling fluid is whirled by the revolving impeller I6 and thrown radially outward of the shaft where'it is guided by the outermost portions of pump housing I2-I3 to the pump outlet |31) from which it is vtaken to the cooling jackets of the internal combustion engine. Leakage from pump housing I2I3 along pump shaft I5 is prevented by pump packing 23 which is maintained snugly against the pump shaft at the sections where the shaft enters the housing by packing nuts 24 fitting about shaft I5 and threadedly engaging end-portions I2c and I3a of the pump housing.

As more particularly indicated above the various radiator fluids, dirt, grime, scale an-d the like encountered in cooling fluids employed in the cooling systems associated with internal combustion engines are effective in causing considerable wear by abrasion, corrosion and erosion of the pump shaft. This Wear is particularly pronounced along the regions where the pump packing is maintained in intimate contactwith the pump shaft in an attempt to avoid leakage of the cooling fluid.

In the practice of my invention excessive wear by abrasion, erosion and corrosion at these points is effectively prevented by including in the shaft I5 a section ofy rustless iron or steel I 5g. This alloy iron or steel analyzes approximately, :1'0%- to 30% chromium, 0% to 20% nickel with or Without supplementary additions of copper, molybdenum, tungsten, aluminum, silicon and the like and the balance subst-anall;T iron. The cor rosion-resistant and wear-resistant section of the shaft is preferably butt-welded, as shown at I'e to the mild steel section during an early stage of manufacture of the sha-ft.

As a matter of convenience in manufacture tle with grooved, slotted, threaded and drilled portions, as indicated above, and finished by grinding and polishing.

Where a) less expensive corrosion-resistant iron or steel, such as a straight` chromium iron analyzing, 12% chromium, .10% carbon and the balance substantially iron, is' employed the sections of corrosion-resistant iron or steel and mild steel or special alloy steel are preferably/machined to-. desired specifications prior to butt-welding the two sections together because of the hardeningd of the corrosion-resistant material as a result'4 of the welding operation. The formed shaft 'is then"ground and. polished to the finished specif' i fication.

The resultant composite pump shaft comprises a corrosion-resistant, wear-resistant section requiring very little machining, which Lis particularly resistant to the formation of a corrosion l product under the conditions encountered in actual, practical use. This section of the pump shaft is resistant to the direct chemical attack of the uid handled by the'pump either in a hot or cold condition. It is resistant to oxidation by the amunt of dissolved air contained in the uid and it is resistant to the electrolytic corrosion arising from diiferences in the 'electro-potentials of the .various materials employed in .the pump construction. This'section of shaft is also highly re. sistant to wear or abrasion* by dirt, grime, scale or the like containedin the uid circulated by the pump and which nds its way into the pump packing.

The composite pump shaft comprisesin addition to the corrosion-resistant, wear-resistant section which enters the pump proper a section which is readily machined giving the desired bearing surface, thrust collar and mounting for the driving element of the shaft.

yWhere desired, asA where an auxiliary device such as an electric generator is drivenfby the pump a section of shaft is extended beyond the pump. This section may be of mild steel or special alloy steel gather than a corrosion-re- 5 sistant iron or steel. For example, referring to the drawing, a generator (not shown) is coupled to the pump shaft 15 by way of a suitable coupling device 25 fastened to shaft I5 in any suitable manner, as by a bolt 2B passing through a hole portion i5i provided in shaft I5 and engaging coupling 25. Where the savings in the cost of the corrosion-resistant iron or steel is warranted the section Iii-of shaft l is made of mild-steel or alloy steel, `butt-welded as at 5 iik to the corrosion-resistant portion of the shaft.

It will be understood thatl thel desirability 4of employing mild steel or alloy steel 'for this endportion lof the shaft is determined by the relative `co of corrosionresistantf steel and mild o steel as compared with the cost of making this additional weld.

Thusit will be seen that there has b'eeniprovided in`this` invention a iiuid pump and method to -30 per cent chromium, 0 per cent to 20 per comprising an intermediate ru'stless iron section practical use, with a minimumof leakage, adjustment and repair. It will be further seen that the pump readily lends itself to emcient and economical production at a minimum of increased cost over heretofore known and/or used generall 5 duty pumps of the class indicated and atfmuch less cost thanl heretofore known and/or used special pumps of the character indicated.

While as illustrative of the practice of-my in- --vention the composite pump shaft is machined to desired specifications, either before or after. the butt-welding operation, and the shaft then iinishedvby grinding without heat treatment being given, it will be understoodthat wheresuch pro. cedure is found desirable, as where a special alloy steel is employed in conjunction with a corrosion-i resistant iron or steel which is hardenable byv heaty,treatment, the .finished shaft may be given a desired heat treatment, either to relieve local strain 'in the metal, as by an annealing treat- 20 ment, or to1 harden both sections of the shaft as by hardening and tempering.

.As many possible embodiments may be made of my invention and as many changes may be madein 'the embodiment hereinbefore set forth it isto be understood that all matter described herein or shownl in thejaccompanying drawing is tobe interpreted as illustrative, and not in a limiting sense.

I claim:

l. In a fluid pump. including a pump housing and a fluid circulating member positioned within said housing, a pump shaft operatively associated with said member and extending outward. 35 ly o said housing, the portion of which that ex# ten within and adjacent said housing and contacts the fluid handled by the pump being of rustless iron analyzing approximately, 10 per cent cent nickel andthe balance substantially iron. 4

2. In a'fluid pump, a pump shaft comprising a rustless iron portion and :a 1ow-carbonsteel portion butt-welded thereto.

3. In a fluid pump', a composite pump shaft I I and low-carbon steel extreme sections butt-welded to said intermediate section'.4

4. In the production of pump shafts, the art which includes, .butt-welding a lengthpof 'rustlesswhich includes, butt-welding-a length iron bar stock to a length .of iron or steel bar '50 'stock and thereafter machining and finishing the composite bar to' desired specications. 5. In the production of pump shafts. the art of rustless iron analyzing approximately, 1o per cent to 3o 55 per cent chromium, 0 per cent to 20 per cent rnickef and #the balance substantially iron toa length of iron or steel bar stock, and thereafter machining land finishing' the composite-har to t desired specifications.- i p60 6. In a iiuidpump, a pump' shaft comprising a rustless iron' portion and alow-carbon steel porof priducing the same,' in which the various ob- 5 jects hereinbefore noted together with many m teriaL'under the conditions of starting and stop piiiig, long periods of idleness, alternating with long periods of operation, and the heat and cold, i l i A A GEORGE C, TIGRE.

shock and vibration, all'encduntered inraotllal,

Vtion welded thereto, said rustless iron portion containing about 18 per cent chromium, about 8 per cent nickel, and 'the ,balance substantially 65 iron. Y

'7. 1n a fluid pump, a pump shaft comprislnga' rustless iron portion and a low-carbon steel portion welded thereto, said rustless iron portion containing about l2 per cent chromium with the balance of the metal substantially iron.

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