US2992615A - Pump for viscous liquids - Google Patents

Description

July 18, 1961 FAZEKAS ETAL 2,992,615

PUMP FOR VISCOUS LIQUIDS Filed Feb. 6, 1956 2 Sheets-Sheet 1 INVENTORJ ATTO RN EYS July 18, 1961 Filed Feb. 6, 1956 G. A. G. FAZEKAS ETAL PUMP FOR VISCOUS LIQUIDS 2 Sheets-Sheet 2 EVEFXTORS M r M ATTO R N EYS United States Patent 2,992,615 PUMP FOR VISCOUS LIQUIDS Gabriel A. G. Fazekas, Floral Park, and Joseph Modrey, Schenectady, N.Y., assignors to The Farmingdale Corporation, Farmingdale, N.Y., a corporation of New York Filed Feb. 6, 1956, Ser. No. 563,750 12 Claims. (Cl. 103-84) This invention relates to a pump for viscous liquids, and particularly to such a pump in which the liquid is put under pressure due to its entrainment by the surface of a rotor, forming one boundary of a clearance space between the rotor and a stator, the entrained liquid being thus driven against a relatively fixed abutment.

It is an object of the present invention to improve the operation of such a pump by providing for differences in temperature between certain parts of the pump.

It is a further object to provide means for cooling the working surface of the rotor.

Another object is to provide for relative cooling of the working surface of the rotor either by means of the liquid being pumped or by means of a separate coolant.

A further object is to provide certain improvements in the form, construction and arrangement of the several parts whereby the above-named and other objects may effectively be attained.

Practical embodiments of the invention are shown in the accompanying drawings, wherein:

FIG. 1 represents a side elevation, partly in vertical section, of a pump according to the invention;

FIG. 2 represents a transverse vertical section on the line II-II of FIG. 1, looking in the direction of the arrows;

FIG. 3 represents a transverse vertical section on the line III-III of FIG. 1, looking in the direction of the arrows;

FIG. 4 represents a detail horizontal section on the line IV-IV of FIG. 2, on an enlarged scale, and

FIG. 5 represents a detail section similar to FIG. 4 but showing a modified form.

.Referring to the drawings, the pump is shown as comprising upper and lower casing halves 1 and 2', which may be substantially or completely identical, and which have semi-cylindrical inner surfaces 3 forming a cylindrical chamber. Adjacent the lateral edges of the surfaces 3, the casing halves are bounded by flat parallel surfaces (shown as horizontal) spaced apart by distances sufiicient to accommodate, on each side of the pump, an inlet spacer bar 4 and a doctor blade 5. The halves are laterally extended to form thickened flanges (best shown in FIG. 2) within which are formed axially extending inlet chambers 6 and axially extending outlet chambers 7 adjacent, respectively, to the bars 4 and the blades 5, the flanges also extending far enough to provide for the assembly of the parts named above by means of bolts 8.

At the inlet end of the pump (the left end of FIG. 1) there is a flanged head member 9, arranged to be bolted to the end of the casing 1, 2 by bolts 10, the matching faces of the head member and casing being separated by a distance plate 11. The inner cylindrical bore 12 of the head member terminates inwardly at the annular shoulder 13, acting as a stop for the outer race of a bearing 14 which is held against the shoulder by a spacing sleeve 15. The sleeve 15 may have its outer cylindrical surface recessed, as shown at 16.

At diametrically opposite points, the head member is provided with fluid inlet passages 17, communicating with the ends of the chambers 6 through openings 11 in the plate 11. The inlet end of the pump is closed by a cap 18, the inner face of which is shaped to form an annular recess 19 registering with the outer ends of the passages 17, and an inwardly extended annular flange 20 providing a firm support for the axial fluid inlet tube 21. Between the head member 9 and the cap 18 is a sealing gasket 22 provided with openings 23 registering with the ends of the passages 17 and with a central opening 24 large enough to leave a free passage around the flange 20. A shaft seal comprising bellows 25 secured to the gasket adjacent the opening 24, spring 26 and sealing ring 27 (preferably of anti-friction material) bears against the collar 28 of the rotor assembly, to be described.

At the drive end of the pump (the right end of FIG. 1) there is a head member 29 arranged to be bolted to the end of the casing 1, 2 by bolts 30, the matching faces of the head member and easing being separated by a distance plate 31. The inner cylindrical bore of the head member terminates inwardly at the annular shoulder 32, acting as a stop for the outer race of a bearing 33 which is held in place by a piano wire or snap ring 34 lodged in an annular groove. The drive end of the pump is closed by the end plate 35, bolted onto the member 29, having a central opening for passage of the drive shaft 36 with suitable packing being provided as indicated at 37. The shaft is driven by a motor M through a clutch or coupling indicated generally at C.

The drive shaft is shown as being an integral extension of the rotor head 38 which is also shaped to provide a firm seat for the inner race of the bearing 33 and which includes a disc-shaped part having its periphery of a size to fit in the cylindrical pump chamber with the desired clearance. The main body of the rotor is formed as a plain hollow cylinder 39, bolted at the drive end to the head 38, and having the inlet head 40 bolted to its other end. The head 40 includes a hollow cylinf drical part providing a seat for the inner race of the bearing 14, carrying the collar 28, and having an axial opening larger than the outer diameter of the tube 21, so as to provide free communication between the interior of the rotor and the recess 19 in the cap 18. The tube 21 extends preferably to a point near the drive-end head of the rotor, as clearly shown in FIG. 1.

The clearance between the outer cylindrical surface of the rotor and the cylindrical walls 3 of the casing may be from a few thousandths to a few hundredths of an inch, depending on the viscosity of the fluid to be pumped and the results desired. The clearance space is closed at each end by the provision of end seals 41 in the form of rings which are tapered inwardly to reduce the width of the bearing surface (and thus reduce the friction) at the edges toward the rotor surface. Said seals 41 are thinner than'the plates 11 and 31 so that they are free to float in the spaces between the casing and the respective head members.

The inlet spacer bars 4 are beveled, as indicated at 4' to provide open passages from the inlet chambers 6 to the rotor-stator clearance space, the inner edges of the bars 4 lying close to the rotor surface but preferably not close enough to produce any friction effect. The doctor blades 5 are preferably su mounted as to be capable of slight axial movement and to float in positions which are most favorable in respect of fluid pressure, clearance, and friction under any given operating conditions. The specific details of such blades are not part of the present invention, but the typical example shown herein includes the provision of a rather narrow edge on the side toward the rotor surface, a fluid accumulating space on the upstream side of said blade edge, radial passages connecting said space with the adjacent discharge passage 7 and openings through the blade connecting said passages: to a clearance provided on the side of the blade toward the adjacent bar 4, .all as indicated on a small scalein FIG. 2. As an alternative, blades more or less resembling those shown in copending application of Modrovsky and Sherwood, Ser. No. 465,078, filed October 27, 1954, now US. Patent No. 2,777,394, might be used.

Fluid leakage return passages are shown at 42 (FIG. 1) in the drive-end rotor head and at 43 (FIG. 4) in the inlet end of the stator casing head 9. The output passages 7 communicate through bores 44 with suitable fittings 45 from which the fluid under pressure is conducted to any desired utilization devices.

In the operation of the pump shown in FIGS. 1 to 4, a source of fluid supply (such as an oil tank, not shown) is put into communication with the tube 21, permitting the fluid to fill the interior of the rotor and flow back through the space around said tube and around the flange 20 to the recess 19; the line of flow continues through the openings 23, passages 17 and openings 11' to the inlet chambers 6, whence the fluid is fed evenly past the bars 4 to the clearance space between the stator and rotor. With the rotor being driven, in the direction indicated by the arrow on clutch C (FIG. 1) and the arrow in the rotor (FIG. 2) the fluid is entrained by the moving rotor surface, is carried around 180 to the doctor blades 5, forming dams or closed valves, and builds up pressure on the upstream side of said blades forcing it to seek escape. The most convenient escape is provided by the radial passages in the blades, so that fluid under pressure fills the discharge passage 7 and is conducted through the bores 44 to any desired point. Since the pressure in the clearance spaces adjacent the doctor blades may become very high, leakage may occur; leakage past the end seals into the spaces containing the bearings is returned to low pres sure parts of the stream through the passages 42 and 43. After the pump is primed and running the low pressure on the input side may even be suction, so that there is no tendency for the fluid to try to escape past the packing 37 or the shaft seal 27, 28. Leakage of fluid circumferentially, past either doctor blade, merely places the fluid in position to be put again under high pressure in the pressure zone spaced 180 from that whence it escaped.

In order to build up pressure adjacent the doctor blades, the fluid must be driven toward said blades. The kinetic driving force is the moving rotor surface, the efliciency of which depends on the adherence of the fluid to said surface, and such adherence is, to a substantial degree, a function of the viscosity of the fluid. Operation of the pump gives rise to friction which tends to raise the temperature of the fluid and of adjacent pump parts, thus lowering the viscosity of the fluid, reducing adherence and giving less eflicient operation. Reduced adherence at the stator surface is not undesirable, hence heating there can be permitted, but in order to obtain relatively greater adherence-or to minimize the reduction in adherence-at the rotor surface it is important that the latter be cooled in some manner. According to the present invention, the cooling is effected by introducing the fluid through the tube 21 at a point where it must traverse the whole length of the rotor, at low pressure and at its lowest temperature, so as to provide continuous cooling of the rotor shell from the inside while permitting the stator to become as hot as it may under any given conditions of friction, conduction and ambiance.

Even if the absolute temperature ditference between the rotor and stator surfaces is small or in the wrong direction, the provision of a rotor cooling circulation system is found to give noticeably improved results over devices lacking such a system.

In the modified construction shown in FIG. 5, the gasket 22 is replaced by a gasket 50 which has a central opening as before but prevents communication between the recess 19 and the passages 17. The recess 19 is provided with an outlet 51 and a separate inlet 52 opens into one of the passages 17, whence the'fluid can flow to the opposite passage 17 through the annular recess 16 in the spacer 15. In this form of the pump, the fluid to be pumped is introduced through the inlet 52, going directly to one chamber 6 and through the recess 16 to the opposite chamher 6, while a separate cooling fluid, having any desired temperature, is introduced through its tube 21, passes along the interior of therotor and back to the recess 19 all as beforebut is then withdrawn through the outlet 51. With this arrangement it is possible to obtain substantially greater rotor-stator temperature differentials, at the cost of somewhat increased complexity.

In either form the cooling fluid (at least) is introduced along the axis of the pump and follows a path which has a definite outward radial component, so that the flow can be started and maintained by the centrifugal action of the rotor on the fluid within it, assuming that no great quantity of cooling fluid has to be lifted far.

The invention is disclosed herein as adapted to use with a pump of the general type of that shown in FIGS. 1 to 5 of co-pending application Ser. No. 465,078, filed October 27, 1954, by Modrovsky and Sherwood (now Patent No. 2,777,394); its adaptation to pumps of the type shown in FIGS. 6 to 9 of said application can readily be eifected along similar lines.

It will be understood that various changes can be made in the form, construction and arrangement of the several parts without departing from the spirit and scope of the invention.

What we claim is:

l. A pump of the character described comprising, a fixed casing containing of cylindrical chamber, a rotor having an imper forate complementary cylindrical surface concentric and interfitting with the surface of said chamber with a clearance therebetween, at least one radially movable elongated axially disposed abutment mounted in said casing to bear against said rotor surface, means for rotating the rotor, means for conducting fluid from a source of supply to the said clearance at a point down stream from each abutment considered circumferentially with respect to the direction of rotation of the rotor, and means for withdrawing the fluid under pressure from a point adjacent to, and upstream from, each said abutment, the said rotor being provided with a passage for the circulation of a cooling fluid near the rotor surface and in effective heat-exchange relation thereto from one end of said rotor to the other end thereof, whereby the fluid in the clearance adjacent the rotor surface is cooler than the fluid adjacent the surface of the chamber, compared on any radius, said cooling fluid passing entirely through the interior of the rotor.

2. A pump according to claim 1 in which the means for conducting fluid to the clearance is in series with, and downstream from, said passage in the rotor.

3. A pump according to claim 1 in which the means for conducting fluid to the clearance is independent from said passage in the rotor, and which includes independent means for supplying to, and withdrawing from, said passage in the rotor a separate temperature-controlling fluid.

4. A pump according to claim 1 in which the rotor is in the form of a hollow cylinder, and in which the passage for the circulation of fluid is formed in part by a tube projecting axially into said rotor to a point adjacent one end thereof and by the space between the outer surface of said tube and the inner surface of said rotor.

5. A pump according to claim 4 in which the means for conducting fluid to the clearance is in series with, and downstream from, said passage in the rotor.

6. A pump according to claim 4 in which the means for conducting fluid to the clearance is independent from said passage in the rotor, and which includes independent means for supplying to said tube and withdrawing from said space a separate temperature-controlling fluid.

7. A pump according to claim 1 which includes annular end seals adjacent the ends of the rotor and so disposed as substantially to close the clearance between the rotor surface and the chamber surface.

8. A pump according to claim 1 in' which leakage return passages are provided at each end of the pump, extending from zones between the rotor and casing beyond the ends of said clearance to points of low pressure in the fluid supply line.

9. A pump of the character described comprising, a fixed casing containing a cylindrical chamber, a rotor having an imperforate complementary cylindrical surface concentric and interfitt-ing with the surface of said chamber with a clearance therebetween, a pair of radially movable elongated axially extending and diametrically opposed abutments mounted in said casing to bear against said rotor surface, a pair of inlet spacer bars each adjacent one of said abutments and constituting a backing therefor, means for rotating the rotor, means for conducting fluid from a source of supply to the said clearance at points defined by the downstream sides of said spacer bars considered circumferentially with respect to the direction of rotation of the rotor, and means for withdrawing the fluid under pressure from a point adjacent to, and upstream from, each said abutment, the said rotor being provided with a passage for the circulation of a cooling fluid near the rotor surface and in effective heat exchange relation thereto from one end of said rotor to the other end thereof, whereby the fluid in the clearance adjacent the rotor surface is cooler than the fluid adjacent the surface of the chamber, compared on any radius, said cooling fluid passing entirely through the interior of the rotor.

10. A pump according to claim 9 in which the means for conducting fluid to the clearance is in series with, and downstream from, said passage in the rotor.

11. A pump according to claim 9 in which the means for conducting fluid to the clearance is independent from said passage in the rotor, and which includes independent means for supplying to, and withdrawing from, said passage in the rotor a separate temperature-controlling fluid.

12. A pump according to claim 9 in which the casing is provided with an elongated inlet chamber adjacent each inlet spacer bar, and with an elongated outlet chamber adjacent each movable abutment.

References Cited in the file of this patent UNITED STATES PATENTS 1,377,914 Newbigin May 10, 1921 2,239,228 Hankison Apr. 22, 1941 2,241,870 Scribner May 13, 1941 2,464,681 Grover Mar. 15, 1949 2,632,395 Jennings et al Mar. 24, 1953 2,751,849 Sherwood June 26, 1956 2,777,394 Modrovsky et al. Jan. 15, 1957 FOREIGN PATENTS 161,038 Germany June 7, 1905 167,350 Great Britain Aug. 11, 1921 402,961 Italy Mar. 31, 1943 1,070,309 France Feb. 17, 1954

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