US1972271A - Metering pump for cellulose compounds - Google Patents

Description

Sept. 4, 1934. F, MCINTYRE METERING PUMP FOR OELLULOSE COMPOUNDS Filed May 12, 1928 Patented Sept-4, 1934 UNITED STATES PATENT OFFlCE METERING PUMP FOR CELLULOSE COMPOUNDS Frederic McIntyre, Newton, Mass.

Application May ,12, 1928, Serial No. 277,245

18 Claims. (Cl. 10S-126) n The present invention relates to metering the oil provided for lubricating external parts pumps of the gear type suitable to be used for with the solution passing through the pump is delivering cellulose compounds in solution at a prevented. uniform regulated known rate of iiow to spin- In the drawing herewith furnished I have illusnerets or spinning-jets to form the filaments Atrated an embodiment, which at present I pre- 60 used in the manufacture of rayon. Gear type fer to others, of the invention above briefly depumps of this class differ from ordinary gear scribed. l pumps used to propel oil, water, etc., in that they Fig. 1 of the drawing is a cross section through are run at low speed and are made so as to prethe axes of the shafts and gears of the pump,

vent as far as possible any leakage whatever of the location of the section being indicated by 65 the solution between the intermeshing teeth of line 1-1 of Fig. 2; the propelling gears. Fig. 2 is a cross section at right angles to the The problemA of lubrication has caused the one previously described on a plane indicated by greatest diiiiculty in the use and yoperation of line 2 2 of Fig. 1;

such meteringpumps in the rayon industry, for Fig. 3 is a fragmentary elevation of the inner 70 oil cannotbe used in any such manner as to ensurface of one of the side plates of the pump danger mixing of the oil with the solution; while casing showing one means of delivering the soluthe solution itself has but poor lubricating qualition for lubrication to the shaft bearings; ties and, upon drying, has a highly detrimental Fig. 4 is a fragmentary elevation of the inner action of cutting or tearing away particles of surfaces of one of the side plates of the pump 75 metal on the surfaces of relatively moving parts. casing. showing another mode of lubricating the In my pending application, Serial No. 218,340, shaft bearings; led September 8, 1927, I have disclosed one Figs. 5, 6 and 7 are detail elevations showing means which I have invented of solving the lubriparts of the means for transmitting motion from cation problem; this being to provide an intenthe external gear to one of the pump gears, and tional and controlled leakage of the cellulosic the provisions for admitting lubricant to such solution, permitting the solution to flow continuparts; ously between rubbing surfaces and escape from Fig. 8 is a perspective view of the sealingdisc the exterior of the pump at such a rate (less than by which mingling of lubricating oil with the enough to permit loss of pressure or to affect the solution is prevented; 85

rate of delivery of the pump) as to utilize what Fig. 9 is a perspective view of one ofthe seclubricating power it possesses, while at the same tions or members of the driving shaft; time giving no opportunity for the solution to Fig. 10 is a detail sectional view of a 'stuffing dry and harden between relatively movable surbox alternative to the external shaft bearing faces and thereby effect its highly deleterious shown in Fig. 1 and having means to prevent abrasive or tearing action. mingling of lubricating oil with the solution.

There are, however, some cellulosic solutions, The pump casing consists of two massive plates leakage of which from the pump is undesirable, 1l and 12 and a center plate 13; all connected tofor a variety of reasons. A different problem of gether by screws 14 or equivalent fastenings, and

o lubrication is presented in the handling of such the side plates being additionally held rigidly in 95 solutions, which I have solved by closing the alinement by massive bars 15, 16, secured fricpump so that evaporation of the solvent cannot tion tight in holes in one of the side. plates and occur and by causing a forced flow of the solution fitted closely into alined holes in the other plate. between rubbing surfaces. The present invention The center plate is preferably made of steel ground is concerned with improvements in gear pumps and finished accurately to uniform thickness with which effect lubrication by means of the solution plane surfaces, and the side plates are preferably being pumped, without external leakage, and of cast viron accurately ground with plane surcomprises new structural features by virtue of faces at the inner side. Cavities 17 and4 18, which the solution is confined without possibility merging into one another, are formed in the cenof solvent evaporation', the solution is forced beter plate to receive the pump gears 19 and 20; 105 tween relatively moving surfaces, provision is while the side plate? have DaSSageWayS 21 Rnd 22 made for 1ubncating the external driving shaft opening through orlces 21m and 22a respectively with oil, and a stop efliciently prevents access of to the inlet space 23 and Outlet Space 24, in the oil to the interior of the parts. All moving parts center plate communicating with the gear cavit of the pump are thus lubricated, while mixing of ties. 'I'hese passages have external openings 25 no and 26 for connection with external conduits leading the solution to andfrom the pump.

The gears are mounted von shafts 27 and 28 which turn in alined bearings in the casing plates 11 and 12. All of these parts, namely, the gears, their shafts, and the bearing surfaces surrounding and enclosing the gears and shafts, are made with the same order of accuracy and with vclearances between moving parts of the same order described in my prior application herein referred to, to the end that the solution may be propelled without loss by the gears at a speed and in quantities of which the speed of the pump is an accurate measure. The gears are fastened to their respective shafts so as to turn them and be turned thereby, by keys 29, each of which in the illustration here given is a pin driven through the shaft and having a projecting head which is received in a keyway in the gear.

The passageways in the casing plates which provide the shaft bearings extend through to the outside of these plates, and their ends, except as to the one which is coupled to the driving means, are enlarged and tapped, and receive closing screw plugs 30. 'Ihe latter are set up tightly with whatever washers or other packing may be necessary and sufficient, so as to prevent evaporation of the volatile solvent in the solution which is forced by the action of the pump into these bearing passages. While the specific construction last described is desirable as affording scope for accurately finishing the bearing passages by grinding, it is not an absolutely essential feature.

For transmitting driving power to the pump gears, 'the casing plate 11 is made with a relatively large cavity 32 in its outer side, coaxial and communicating with the bearing of shaft 27, and an annular rib 31 on the plate (in this illustration of the invention) surrounds and extends such cavity. The shaft has a transverse rib 33 on its extremity protruding from the bearing into said cavity and entering a complemental slot 34 (see Fig. 5) in a disk or plate 35, which loosely occupies such cavity. This disk has peripheral notches 36 in opposite sides.

A cover 37 is secured detachably to the end of boss 31 and is provided with an inner hub 38, Which enters the cavity but terminates short of the bottom thereof, and an outer hub 39 projecting outward andforming the bearing for a driving gear 40.

This cover or plate 37 with its hubs 38 and 39 may be considered also as a flanged sleeve. It has a central passageway, approximately, although not necessarily exactly, alined with the bearing for shaft 27, in which are located shaft sections 41 and 42 in rotation transmitting engagement through a transverse rib 43 on the end of one of them entering a complemental groove in the adjacent end of the other. The shaft section 41 is provided with an integral head 44 having axially projecting lugs 45 spaced and dimensioned to enter the notches 36 in the disk 35. The associated shaft section 42 is coupled to the gear 40 by means of a strap or bar 46 extending across the end of the shaft section and anchored at its ends in the gear. The shaft section has a transverse end rib 47 entering a slot in the strap. A holding plate 48, having a central hole through which the shaft section 42 passes, is secured by screws 49 to the end of the hub or sleeve 39, and overlaps the central part of the gear 40. Thus, as the plate or flange 37 is secured to the casing by screws entering holes 50 in this plate, the parts are all secured in assembled relationship.

of sleeve 38 and the flange or collar 44 on shaft section 41. The opposite faces of this ring are accurately finished in trueplanes perpendicular to the axis of the ring, and the contiguous faces of the sleeve 38 and ange 44 are likewise accurately finished in planes truly perpendicular to the same axis. Such contiguous surfaces are pressed closely against one another by the pressure of the solution passing through the pump in the manner presently described, and the ring 55 serves as a sealing means to prevent escape of the solution through the bearing of the driving shaft or the lubricant passages above described, and to prevent also entrance of lubricating oil into the interior of the pump where it could mix with the solution.

In the embodiment of the invention shown in Figs. l, 2 and 4, the surfaces of each of the casing plates 11.and 12 contiguous to the pump gears are provided with narrow shallow grooves leading from approximately the point of intersection of the outermost circumferences of the gears to the shaft bearings at the inlet side of the pump. The grooves so provided in the plate 12 are shown at 56 and 57 in Fig. 4. The corresponding grooves in plate 11 are shown in Eig. 2, being indicated by dotted lines where they pass behind the gears 19 and 20. The grooves in each plate at and near their junction point 58 are'uncovered more or less at all times by the gears so that they receive the solution entering the space 23 from the inlet passage 21. The grooves extend on curved lines tothe shaft bearings, represented in Fig. 4 by the holes 59 and 60, and the movement of the gears over the grooves sweeps the -solution contained therein to the bearings. The solution spreads over the surfaces of the shafts and their bearings, lubricating them. 'Ihere is also in the plate 12, opening to the inlet space 23, a cavity 6l from which passages 62 and 63 lead to the enlargements of the shaft bearing passages in which the closing plugs 30 are placed. Other passages similar to 62 and 63 are provided in the plate 11 leading from the chambers at the ends of the shaft bearings in the latter .plate to the inlet orifice of the pump, or other part of the inlet passage, or other orifice equivalent to that shown at 61. Paths are thus provided for circulation of the solution which passes through each of the bearings in each plate.

The solution which passes through the bearing of shaft 27 in plate l1 enters the cavity in the outer side of said plate in which the flange 44 of shaft 41 is contained. It fills all the otherwise unoccupied space in this cavity and enters holes 64 in the flange 44, lubricating the contact surfaces of this flange and the sealing ring 55. The pressure imposed by the pump on this solution and transmitted into the cavity exerts pressure on thel sealing ring, holding it in close contact with the adjacent end face of the sleeve or hub 38. At the same time the solution lubricates the contiguous surfaces of the flange 44 and ring 55. Thus the moving parts external to the pump are lubricated by oil, the parts within the pump to which oil cannot be admitted are lubricated by the solution, and an eilicient seal is provided, the rubbing surfaces of which are also lubricated, to prevent mixing of the external lubricant with the solution passing through the pump. 4

In order to prevent excessive pressure being imposed on the solution entrapped between the teeth of the pump gears coming into mesh at the delivery side, I provide a shallow recess in the face of one of the side plates, in this case the plate 1l, or permissibly in both plates, extending beside the paths in which the teeth of the respective gears travel in approaching each other, from a point outside of the location where the teeth rst make'contact with one another toward the common plane ofthe gear axes. It will be understood that each tooth of either-gear, in entering the mating tooth space of the other gear continues -to penetrate further into such space after making tangent contact with the tooth faces bounding such space. The solution thus entrapped in the diminishing tooth space would be subjected `to great pressure and would cause great pressure of the gear shafts on their bearings y if no avenue of escape were provided other than the minute clearances between the sides of the gears and the faces of the contacting side plates, owing to the fact that the gears are made and located with practically entire absence of backlash between their teeth. Butthe cavity 65, extending from beside the location Where the penetration of the gear teeth into their complemental spaces is the maximum to a location outside of the meshing point, permits free escape to the outlet of the solution thus entrapped and so prevents such excessive pressure being thus imposed.

I may, however, utilize the pressure thus irnposed on the solution as a means for forcing the solution to the shaft bearings and thereby effecting lubrication under greater pressure than is created by the wiping action of the gears in .propelling oil through the grooves 56 and 57. Provisions for effecting such forced feed lubrication are shown in Fig. 3. This is an alternative construction to that for the wiping feed. In this instance grooves 66 and 67 are formed, preferably in both side plates, of such dimensions and in such locations that each is open at one end to the base portion of every tooth space in one of the gears from the position where the space becomes blocked by an entering tooth of the other gear, and throughout the period while its volume is being diminished by further penetration of the entering tooth, and each groove is separated from the other. These grooves lead separately to the two shaft bearings, around which are preferably spiral grooves 68 and 69, cut either in the walls of the bearings, or in the sides of the shafts, if preferred, to give free course for the liquid. The return passages '70 and '70a from the chambers at the ends of the shaft bearings lead to the space at the outlet side of the pump, those in the plate l2 conveniently entering the discharge orifice 22a, while the corresponding passages in the plate 11 lead to a recess in the plate opening to the outlet space 24 of the center plate. The reason for placing the return passage at'the outlet side of the pump is to relieve the high pressure which may be thus impressed on the liquid and to ensure a positive circulation over the faces of the -gears and bearings for lubrication.

A construction of cover plate and its adjuncts alternative to that previously described is shown in Fig. 10.

An alternative form of cover member and associated parts is shown in Fig. l0. A single shaft '7l is here substituted for the two-part shaft 41- 42, having a notch '72 at one end and a tongue '73 at the other end for coupling, respectively, with shaft 27 and driving gear 40. A sleeve packing '17 of cork, or other suitable material, is placed in a stuiling box within this cover member, to surround shaft 71, and is compressed by a gland 76. A thrust bearing washer or disk is interposed between the end of the cover and flange 44a of the shaft. Passages 79 and 80 in the shaft,'and holes in the flange 44a like the holes 64 of Fig. 9 admit/the solution from within the pump to the rubbing surfaces, for lubrication. I have found that solutions of the kind here contemplated cooperate excellently with cork to make substantially frictionless surfaces, in the situations here shown, while cork makes a sufficiently liquid tight packing to prevent escape of the solution or entrance of the lubricating oil.

It is to be understood that the driving gear will be mounted on the exterior end of the stuffing` box, and may be lubricated, exactly as shown in x pump is thus adapted to serve as an accurate metering pump maintaining a constant delivery even against considerably varying back pressures. But at the same time adequate provision is made for forcing the solution between all the moving parts and the adjacent stationary surfaces and for preventing evaporation of the solvent, such as would permit drying and hardening of the compound between bearing surfaces and scoring vsuch surfaces.

What I claim and desire to secure by Letters Patent is:

l. In a metering pump of the character set forth, a casing having shaft bearings and pump gear cavities, intermeshing pump gears located in said cavities, shafts occupying said bearings on which said gears are respectively mounted, the casing having an external chamber into which one of said shaft bearings opens, a cover for said chamber having a shaft bearing alined approximately with the last named bearing and an endthrust bearing at its end which faces said chamber, said cover having an oil inlet leading to the shaft bearing surface and a passage from said inlet to the end-thrust bearing, a driving shaft occupying the shaft bearing in the cover having a flange located in said chamber and overlapping said end-thrust bearing, coupling means between said flange and the adjacent pump gear shaft for transmitting rotation from the first shaft to the other, and a sealing Washer between the flange andthe end-thrust bearing arranged to be pressed against the latter by the solution in the pump, the before-namedpassage serving to conduct lubricant to the outer face of said washer.

2. In a metering pump of the character set forth, a casing having shaft bearings and pump gear cavities, intermeshing pump gears located in said cavities, shafts occupying said bearings on which said gears are respectively mounted, the

casing having an external chamber into which one of said lshaft bearings opens, a cover for said chamber having a shaft bearing alined approximately with the last named bearing, said cover having an oil inlet leading to the shaft bearing surface and a passage from said inlet to the inner end face of the bearing, a driving shaft occupying the bearing in the cover and having a flange located in said chamber, coupling means between said flange and the adjacent pump gear shaft for transmitting rotation from the first shaft to the other, and a sealing washer between the ange and the adjacent end face of the cover arranged to be pressed against thelatter by the solution in the pump, the before-named-passage serving to conduct lubricant to the outer face of said washer, and the flange having an opening through it adapted to convey solution to the inner surface of the washer for lubricating the latter surface.

3. In a metering pump, a casing, complemental pump gears contained and operating in said casing, a shaft on .which one of said gears is mounted, the casing having a bearing for said shaft and an external chamber into which said bearing opens, and a shaft having a non-circular extremity projecting into said chamber, a disc located in said chamber having a hole complemental to said projection and receiving the same, and also having notches at either side of such hole, a cover secured to the casing over said chamber having an internalshaft bearing and an external bearing surface, a driving shaft section located in the said internal bearing having a ange in the chamber provided with projections entering the before. mentioned notches of the disc, a driving gear mounted on the external bearing of said cover, and coupling means between said gear and said driving shaft section,

the driving gear having an oil hole leading to the external bearing surface and the cover having passages ext-ending to its internal bearing surface and to the inner end face thereof, combined with a sealing washer lying against the said end face and between the latter and the flange of the driving shaft section.

4. A metering pump comprising a casing having internal gear cavities and shaft bearings, the latter being closed at both ends, complemental pump gears fitting rotatably in said cavities with minimum clearance between their surfaces and the boundaries of the cavities and with substantial absence of backlash between their teeth, shafts fitting said bearings rotatably and terminating short of the end closures thereof, separated grooves formed in the end walls of the gear cavities leading each from the outlet side of the pump to one of the respective shaft bearings, and the casing having passages leading from each of the shaft bearings to a space in the gear cavities outside of the circumference of either gear.

5. In a gear pump of the character described, a casing surrounding the pump gears with minimum clearance and having shaft bearings, said casing comprising plates in which adjacent to the ends of the gears are channels leading to the respective bearings from the inner surfaces of said plates at points which are overpassed by the rotating gears, and the plates having return passages from the outer ends of the bearings to their surfaces which bound the internal pump space.

6. In a gear pump of the character described, a casing surrounding the pump gears with minimum clearance and having shaft bearings, said casing comprising plates in which adjacent to the ends of the gears are channels leading to therespective bearings from points beside the locations vin volume by the entrance of occupied by the tooth spaces in the respective gears when such spaces are blocked and contracted by entering complemental gear teeth; said channels being formed to prevent flow, elsewhere than to the bearings, of the uid entrapped between the intermeshing gear teeth.

7. In a gear pump of the character described, a casing surrounding the pump gears with minimum clearance and having shaft bearings, said casing comprising plates in which adjacent to the ends of thegears are channels leading to the respective bearings from points beside the locations of the tooth spaces in the respective gears when such spaces are blocked and contracted by entering complemental gear teeth, said channels being otherwise closed to prevent ow, elsewhere than to the bearings, of the fluid entrapped between the intermeshing .gear teeth, and means for returning solution forced through said bearings to the outlet side of the pump.

8. In a gear pump of the character described, a casing surrounding the pump gears with substantially leakage vpreventing closeness and having shaft bearings, the walls of said casing contiguous to the ends of the gears having unconnected grooves, each of which leads from oneof the bearings to the location occupied successively by the tooth spaces of the gear centered on the same bearing when such spaces are blocked and reduced meshing teeth on the other gear. Y

9. In a metering pump of the character described having a casing, intermeshing pump gears in said casing and bearing means for positioning said gears in the casing, means for utilizing the pressure imposed upon liquid entrapped in the tooth spaces of the respective gears for lubricating said bearing means comprising separate grooves in the casing walls contiguous to the en'd faces ofthe gears, each-leading to the bearing means of one gear from thelocation occupied successively by the tooth spaces of the same gear when such spaces are blocked and diminished in liquid containing volume by entering teeth of the other gear.

10. In a metering pump having a casing, intermeshing pump gears, and centering bearing means for the respective gears, a lubricating groove 11. A metering pump of the character set forth comprisingv a casing, Dump gears within said casing, an interior shaftto which one of said gears is secured, an exterior driving shaft coupled to said interior shaft, a cover embracing said exterior shaft and having an end thrust bearing, said shaft having a ange overlapping said end thrust bearing, and a sealing member interposed between said flange and end thrust bearing, the flange having holes through which the liquid being pumped is admitted to the contiguous face of the sealing member for lubrication.

12. In a metering pump, a casing, pump gears within said casing,l an interior shaft to which one of said gears is secured, an exterior driving shaft coupled to said interior shaft, a cover secured to the casing lhaving an internal bearing for said driving shaft and a thrust bearing at its inner end, the driving shaft having a flange adjacent to its inner end overlapping said thrust bearing, means for lubricating the shaft bearing in said cover, and a sealing disk between the shaft flange and said end thrust bearing to prevent mingling of the shaft lubricant with the fluid acted on by the pump.

13. In a metering pump, a casing', pump gears within said casing, an interior shaft to which one of said gears is secured, an exterior driving shaft coupled to said interior'shaft, a cover secured to the casing having an internal bearing for said driving :shaft and a thrust bearing at its inner end, the driving shaft having a flange adjacent to its inner end overlapping said thrust bearing, means for lubricating the shaft bearing in said cover, a sealing disk betweenthe shaft flange and said end thrust bearing to prevent mingling of the shaft lubricant with the fluid acted on by the pump, and means for admitting such fluid between the shaft flange and sealing disk for lubricating the latter by means of such fluid. f

14. In a metering pump comprising a casing, intermeshing pump gears, a shaft secured to one of said gears and a bearing in the casing for said shaft, a channel in the casing adjacent to the end face of one of said gears leading to said shaft bearing from the location occupied by the successive tooth spaces of said gear when blocked by the entering teeth of the mating gear and being otherwise closed against escape of liquid, whereby the pressure imposed on the liquid entrapped in such spaces forces flow of the liquid through said groove and shaft bearing, the bearing being closed at the outer end of the shaft,

and the casing having a return passage from the bearing to an interior space through which fluid is propelled by thepump gears.

15. A rotary pump or the like comprising two toothed pumping wheels meshing with each other, a casing in which the said wheels are mounted .which closely fits the faces and a portion of the 16. A rotary pump or the like comprising two toothed pumping wheels meshingwith each other, a casing in which the said wheels are mounted which closely fits the faces, and a portion of the outer periphery, of each wheel and has a relief passage extending from a position communieating with the clearance space between the crown of each tooth in turn and the base of the space between two teeth of the other wheel in which the iluid is trapped at the meshing point of the wheels during operation of the pump, and means whereby fluid is automatically led from the aforesaid relief passage to the mountings for the said toothed wheels to serve as the lubricant therefor.

1'7. A rotary pump or the like comprising two toothed pumping wheels meshing with each other, a casing in which the said wheels are mountled which closely flts the faces, and a portion of the outer periphery, of each wheel and has a relief passage extending from alposition communicating with the clearance space between the crown of each tooth in turn and the base of the space between two teeth of the other wheel in which the fluid is trapped at the meshing point of the wheels during operation of the pump, means whereby fluid is automatically led from the aforesaid relief passage to the mounting for one of the said toothed wheels to serve as the lubricant therefor, and means whereby the said lubricant is discharged from the mounting and led to the output chamber of the pump.

18. A rotary pump or the like comprising two toothed pumping wheels meshing with each other, a casing in which the said wheels are mounted which .closely fits the faces, and a portion of the outer periphery, of each wheel and has a relief passage extending from a position communicating with the clearance space between the crown of each tooth' in turn and the base of the space between two teeth of the other wheel in which the fluid is trapped at the meshing point of the wheels during operation of the pump, a shaft on which one of the said toothed wheels is flxedly securedl to rotate therewith and a bearing in the said casing for the shaft, which bearing is formed with a lubricating groove extending along the substantial portion of the length of the bearing and almost completely encircling the shaft but terminating at one end at the said relief passage and leading at the other end to the output chamber of the pump.

FREDERIC MCINTYRE.

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