US1379587A - Pump - Google Patents

Description

J. P. FISHER.

PUMP.

APPLICATION FILED AUGJGI I919.

lPa beme May 1921.

2 SHEETSSHEET 1.

HI I I IM I HH nu I u #m u HI I nI IIIIIIII -4L .T

s51, WM arm/M 1. P. FISHER.

PUMP.

APPLICATION FILED AUG-l6, I919.

Patented May 24L, 1921.

2 SHEETSSHEET 2.

JAMES P. FISHER, 0F BARTLESVILLE, OKLAHOMA, ASSIGNOR,

BY MESNE ASSIGN- BL'ENTS, TODOEERTY RESEARCH COMPANY, @F NEW YORK, N. Y., A CORPOEA= T1016 U1? DELAWARE.

To all whom it may concern:

Be it known that 1, JAMES P. FISHER, residing at Bartlesville, in the county of Washington, State of Oklahoma, have invented certain new and useful Improvements in Pumps; and v1 do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art tov which it appertains to make and use the same.

This invention relates to pumps, and more particularly to high speed gear pumps adapted to pump fluids under high pressures and at high temperatures.

Tn the refining of mineral oils and in many other industries, there frequently arises-the problem of pumping liquids under pressure at high temperatures, the temperature extending in some cases from 500 F. or 600 F. to nearly red heat. The pumps used for pumping liquids at ordinary temperatures are notsuitable for working at these higher temperatures, owing to the rapid destruction of the packings and to the melting of the bearing meta-ls- Difficulties in the way of lubrication and in theprovision of liquid tight closures are also encoun-' tered at high temperatures, which are not met at ordinary temperatures. Consequently, it has been found practically impossible to use any of the ordinary liquid pumps for high temperature operations.

The object ofthe present invention 15 to provide a pump which is very efiicient for pumping liquids under pressure at hlgh temperatures.

For pumping liquids under hlgh temperature and pressure and especially thick, heavy or sticky liquids, rotary gear pumps are the most suitable, because of their simplicity and the absence of valves and other reciprocating parts, which are 11able to fail or to get out of order. Also when pumplng easily emulsifiable mixtures of 011s or other -liqu1ds, gear pumps have the (advantage that they cause less disturbance in the con-- dition of the liquid and thus avoid theformation of emulsions. Further, high speed gear pumps give a steady, continuous deliver When pumping liquids under high pressure, the gears of a gear pump are exposed to the unbalanced back pressure of the liq uid being pumped. As a result, a heavy pressure is thrown on the bearings and sup- Specification of Letters Patent.

Application filed. August 16, 1919. Serial No.

Patented May 24-, 1921.. 311852.

porting shafts causing high friction losses and overheating of the bearings. Under these conditions, it is very difiicult to maintam a packing for the gears which will give an eficient pumping action and therefore objects in view, the the improved gear I illustrated in the accompanying drawing, in

whlchz Figure 1 is a planview with parts broken away, of a gear pump embodying the preferred form of the invention.

Fig. 2 is a front elevation of the gear pump shown in Fig. 1.

Fig. 3 is a vertical sectional view of the gear pump taken on the line 8-3 of Fig. 1.

Fig. 4c is a vertical sectional view of the gear pump on the line 44 of Fig. 1-.

Fig. 5 is a detailed sectional view of a bearing of the gear pump taken on the line 55 of Fig. 4e.

Fig. 6 is a front elevation of the gear pump together with its driving mechanism.

Fig. 7 is a detailed sectional view of a bearing of the gear pump taken on line 7-7 of Fig. 1.

In the gear pump illustrated in the drawings, the liquid to be pumped enters through an inlet 10 to a suction chamber 12 of the pump 14. The fluid in the chamber 12, enters and fills spaces 16 between gear teeth 18 on gear wheels 20 and 22. By the rotation' of the gears 20 and 22 the bodies of liquid contained in the spaces 16 are car- Accordingly, another object of the invenhas from the chamber 28through the gears 20 and 22 back to the inlet chamber 12 by the intermeshing of the gear teeth 18. From the chamber 28 the liquid is delivered through an outlet opening 42'.

In all gear pumps, apart of the liquid carried from the chamber 12to the chamber 28 by the gears 20 and 22 leaks back to the chamber 12. It has been found that this leakage takes place mostly between the ends to the bearing'or pressure sides of the gear shafts. The pressure of this .delivery side liquid balances the back pressure of the liquid on the gears and tends to force, or float the shaftsoif from the shaft bearings. The fluidby-passed to the shafts flows slowly around the shafts to the low pressure side of the shafts and escapes through'a passageway to the low pressure or inlet side of the um I In order to balance the back pressure of the liquid in the chamber 28 on the gears 20 and 22, a small part of this liquid passes through which are filled with a mass of fibrous, filtering material. The liquid ,in passing through this filtering material will be freed from particles of grit and solid material which might injure the bearings. From the filter chamber 46, the liquid passes through ducts 48 and 50, (Fig. 4) to annular recesses 52 and 54 respectively, surrounding-the bearings of the shafts 30 and 32. The liquid flows through the recesses 52 and 54 to that part of the recesses opposite the ducts-48 and 50 and passes through openings 56 and 58 in and 62 'surroundin the and 58 enters distributing channels 64 and 66 extendin lengthwise nearly the entire length of t e bearing collars 60 and 62. The ends of the bearing collars 60. and 62 are made to closely fit the journals of the shafts 30, 32, 34 and 36 and prevent any appreciable amount of liquid from escaping from the distributing channels 64 and 66 between the ends of the collars and the shafts. Throughout the length of the dis-. tributingchannels 64 and 66, the interior 38 and 40 and that there is comparducts 44, in each of the bearing castings 38 and 40 to filter chambers 46,

, meshing of the teeth of the .bearing collars 60 1 'ournals of theshafts 30 and 34 an 32 an 38 respectively. The liquid passing through the openings 56 f diameter of the bearing collars 60 and 62 is made slightly larger than the diameter of the shafts 30 and 32. to form a very narrow space between the bearing collars and the shafts, through which the liquid flows under a drop in ressure to collecting channels 68 and 70. lhe channels 68 and 70 are extended through one end of the bearing collars 60 and 62 and communicate with ducts 72 and 74, connecting the channels 68 I ectively to a collecting chamber and-70 r 76. The liquid flowing from the distributing channels 64 and 66 around the shafts 30 and 32 to the collecting channels 68 and 70, flows through the open ends ofthe channels 68 and 70 and thence through the ducts 72 and 74 to the collecting chamber 7 6. From the collecting chamber 76 the liquid asses through a duct.78 (Fig. 1) to the- 1n1et chamber 12 of the pump.

From the foregoing, it is manifest that the high pressure sides of the journals of the. shafts 30, 32, 34 and 36 are those which face toward the low pressure or inlet side of the pumping gears 20' and 22. Conversely, the low pressure sides of the shaft journals face toward the outlet or high pressure sides of the pumping gears.

' The extent of the bearing surfaces of the journals of the shafts 30, 32, 34 and 36 is so proportioned with relation to the dimensions of the gears, that the fluid pressure on the shafts will just about balance the back pressures on the gears. To accom lish this, the sum of the projected areas 0' the shafts is made equal to, or greater than the sum of themaximum projected areas of the gears. In the specification and claims of this application, the words projected area are .used in the ordinary engineering sense to denote the area of the shadow cast by the respective parts under the action of paral- Y lel rays of light upon a plane surface dis- %osed at right angles to the rays of light.

onsequently, the maximum projected area of the gears, for'example, e

of the gears multipliedfby t e sum of their diameters minus. by reason of the intergears, the depth of a tooth on the gears; Inasmuch as the ressure of the oil introduced into the bearmg collars 60 and 62 may hot be entirely spent in passing from theopenings56 and 58 to the other sidesof 'the shaftjournals and may'consequently exert some influence tending to move the shafts in the same direction asthe' back pressure on the gears,

ptrsojected areas of the jour-'- is preferably somewhat the sum of the nals of the sha greater than that .of the ears. In the illustrated construction which with very satisfactory results, the maximum Erojecte area. of the gears and the commed projectedarea of the shaft journals are approximatelyin theratio of 3 to 5. It

has been operated 110 ualsthe length pollar or Jlnto this pro ectmn or collar is threaded aerate? is manifest that when the pressure of the fluid on the sides of the shafts 30, 32, 3d and 36 facing toward the intake side of the pump chamber counterbalances the back pressure on the pumping gears, the shafts will be, in-efiect, floated away from the bearing collars 60 and 62, so that they are sup ported against rearward thrust by' a constantly renewed cushion of fluid between their journals and the bearing. collars. By thus floating the shafts away from the hearing surfaces, it is possible to dispense with the sheet or layer of bearing metal used for lining the bearings in the common types of gear pumps. The bearing collars 60 and 62 may be made of cast iron or steel or other metals not fusible at relatively high temperatures. The bearing surfaces, of the shafts at each end of the gears will of course be made equal, so that the pressures on the gears will be properly balanced.

To provide power for driving the gears, the shaft 30 is extended through the end of the bearing casting 38 and is provided with a driving pulley at its free end. It is diiiicult if not impossible, to provide a liquid tight stufilng box on the bearing casting 35, because, at the temperatures at which the pump is operated, the stuffing material would rapidly deteriorate. Moreover, at these high temperatures, the liquid has a greater fluidity and has a consequently greater tendency to leak through the studing devices. lo overcome these difficulties, the bearing casting 38 has an integral projection. 82 around the shaft 30.

one end of a pipe 84m surrounding the shaft 30. the outer end of the pipe 84, there is provided a stuffing box 86 and gland 88. Liquid from the ducts 72 and 74.- passes into an annular compartment 90, formed between the shaft 30 and the pipe 84: and completely fills said compartment. The oil in the compartment 90 will foe cooled by radiation from the walls of the pipe 84 and by the time it reaches the stufi i'ng box 86, its temperature will be low enough so that the packed joint in the stuffing box 86 may be easily prevented from leaking. lhe oil will not be actively circulated in the chamber 90 and consequently the oil therein will be comparatively cool.

Since the liquid in the chamber 90 is in communication with the low pressure ducts 72 and 74 and through these ducts and the collecting chamber 76 with the low pressure chamber 12 of the'pump 1d, the pressure tending to force the liquid out of the chamber 90 through the stuiiing box 86 will be comparatively small, thereby further reducing the tendency of liquid to leak through the stuiiing box 86.

The bearing castings 38 and 40 and the main body of the pump 14 are held together by four bolts 92. To take the pump apart, for cleaning or repair, nuts 9% on the bolts 92 are removed, whereupon. the bearing casting a0 may be removed from the body of the pump 14:. The gears 20 and 22 may then be removed through the open nd of the pump section 14, leaving every part of the pump accessible for inspection or repair.

Vfhile the pump has been described in connection with high temperature operations, it will be understood that it is not limited to use under these conditions, but will be equally advantageous when used at ordinary temperatures.

The preferred form of the invention, having been thus described, what is claimed as new l. high speed gear pump, which coniprises a gear chamber, a pair of intermesh ing pumping gears disposed in substantial contact with walls of said chamber, rotatable shafts rigidly fastened to and sup porting said gears, means for conducting fluid from the high pressure side of said gears to the sides of said shafts facing toward the low pressure sides of the chamber, and means for withdrawing fluid from the low pressure sides of the shafts.

2. In a high speed gear pump having pumping gears supported on rotatable shafts and bearings for the shafts, the combination of means for introducing fluid un der pressure to the bearing surfaces of said shafts adjacent to the low pressure side of the gears, and means for removing fluid from the low pressure sides of said shafts.

3. In a high speed gear pump having a pair of pumping gears rigidly supported on rotatable shafts, the combination of means for conducting fluid under pressure from the high pressure side of said gears to the bearing surfaces of said shafts adjacent to the low pressure side of the gears, and means for withdrawing fluid from the low pressure sides of said shafts to the low pressure side of the pumping gears.

d. In a high speed gear pump having a pair of intermeshing pumping gears rigidly supported on rotatable shafts, the combination of ducts leading from the high pressure side of the pump to the bearing surfaces of the shafts, means for filtering the material passing through the ducts, and ducts leading from the low pressure sides of the shafts to the low pressure sides of the pumping gears.

5. In a high speed gear pump having pumping gears rigidly mounted on rotatable shafts and bearings for the shafts, the combination of ducts leading from the high pressure side of said gears to the portion of the bearing surfaces of the shafts facing toward the low pressure sides of the'gears, means for distributing fluid from said ducts throughout the length of the bearing surfaces, and means for withdrawing fluid from the low pressure sides of said shafts pumping chamber, a

to the low pressure sides 'of said gears.

6. In a high speed gear pum the combination of pumplnggears rigi ly supported on rotatable shafts, journals for said shafts the projected areas of whichare equal to, the projected area of the or greater than, pumping gears, means for conducting fluid under pressure from the high pressure side of said gears to the bearing surfaces of the shafts, and means for withdrawing fluid from the low ressure sides of the shafts.

7. In a big speed gear pump, the com-.-

pumping gears divi chamber into twosections,

high pressure side of the gears to the sides of the journals facing toward the low pressure side'of the chamber to cause pressure on the shafts in directions counter to the back pressure on the gears.

- bination of a pair of intermeshm gears rigidly supported on rotata and means for supporting said shafts against the back pressure of the fluid being" id y supported-on, rotatable sha s 9. ha high speed gear pump,

pumping e shafts,

pumped by a cushion of fluid. under pressure. v I

10. A high speed gear pump comprising a air of intermes'hing pumping ars rig withm a caslng, power means for rotating said shaft fastened to an extension of one of the shafts outside of the casi ,asleeve surroundin said extension and astened to the wall 0 said casing, and a stufling box at the free end of saidsleeve.

11. The combination with a high speed gear pump casing of a. driving shaft, an air-cooled collar surrounding said shaft and having a liquid-ti casing, and a stu of said collar.

12. The combination with a. high speed gear. pump casing of a.- drivin shaft, an air-cooled collar surrounding said shaft and having a liquid-tight connection with said casing, a stuffing box at the free end collar, and means for admitting li ng box at the free end uid to said air-cooled collar only from t e low pressure side of said pump casing.

13. In a high speed gear pump which comprises a pumping chamber, a pair of intermeshing pumping gears, rotatable shafts direction opposite compri a1 8mg 1 15.'A high speed gear .lars at the pressure sides of said s and means for the com- 7 said pumpin ht connection with said of said supporting said gears, bearing collars surrounding said shafts, and means for introducing fluid under pressure between the said shafts and said bearing collars in a to the direction of back pressure on said gears and withdrawing fluid from the low pressure sides of sai shafts.

14. A high speed gear pump, comprising a pumping chamber, apair of intermeshin pumping ears in said chamber supporte I on rotatable shafts, bearin collars surrounding said rotatable sha conducting fluid from the delivery side of said gears and distributing said fluid between the said shafts and said bearing collars on the sides of the shafts facing toward the low pressure or intake side of the pump, and means for withdrawing fluid from the sides of the shafts opposite from the first-mentioned sides to the intake side of the pump. t

pump, comprislng a pumping chamber, a pan of intermeshing pumping gears in said chamber supporte on rotatable shafts, bearing collars surrounding said rotatable shafts, means for conductlng fluid from the delivery side ofsaid gears and distributing said fluid between the said shafts and said bearing colafts,

filtering said fluid passing to said shafts.

16. A high speed gear pump which comprises a pumping casing, a pair of intermeshing pumping gears in said casing rigidly supported on rotatable shafts, ducts leading from pump to the bearing surfaces of said shafts, ducts leading from the low pressure sides means for the high pressure side of said I of said shafts to the low pressure sideof tating saids a s fastened to an extension of one of the vshafts outslde' said casmg, a sleeve surrounding said extension and 'fass, power means for rotened to the wall of said casing, the interior I of said sleeve commumcating with .the duct leading from the low pressure side of said driving shaft, and a stufiing box .at the free end of said sleeve.

17. A high speed gear pump which comprises a pumping chamber, a pair of rotatable shafts, intermeshin pumping gears rigidly sup orted on sai rotatable shafts, and journa s for said shafts having a combined than t gears.

18. A high speed gear pump comprising a chamber, a pair of intermeshing pumping gearsmounted in the chamber, shafts for e pro ected area' of the pumping 120 projected area equal to, or greater the'gears provided with journals having a combined'projected area equal to or greater than the maxlmum projected area of the gears, bearings for the journals, means for conducting fluid from the high pressure side of the gears to the portions of the bearing surfaces of the journals facing toward the low pressure side of the pump chamber to counter-balance the back pressure of the fluid on the gears,'and means for withdrawing fluid from the opposite sides of the journals. v

19. A high'speed gear pump comprising a chamber, a pair of intermeshing pum ing gears mounted in the chamber, sha ts for the gears provided with journals having a combined projected area equal to or greater than the maximum projected area of the gears, bearings for the journals, and means for effecting circulation of fluid from the pump chamber through said bearings of a character such as to exert fluid pressure on the journals of the shafts substantially counterbalancing the back pressure of the fluid. on the pumping gears.

20. A. high speed gear pump comprising a chamber, a pair of intermeshmg pumping gears mounted in the chamber, shafts for the gears provided with journals having a combined projected area equal to or-greater than the maximum projected area of the gears, means for conducting fluid from the high pressure side of the pump chamber to the sides of the journals facing toward the low pressure side of the gears to counterbalance the back-pressure of the fluid on the gears, and means for Withdrawing fluid from the opposite sides of said journals to the low pressure or intake side of the pump chamber.

21. A method of lubricating a high speed gear pump having intermeshing pumping gears carried on rotatable shafts, which comprises conducting fluid under pressure from the delivery side of the pump to the portion of the bearing surfaces of the shafts facing toward the intake side of the pump, and Withdrawing said fluid from the low pressure sides of said shafts to the intake side of the pump.

In testimony whereof I aflix mv si ature.

JAMES P. J FIS ER.

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