US2796030A - Rotary pump for handling viscous materials - Google Patents

Description

June 18, 1957 F. P. NEBEL 2,795,030

ROTARY PUMP FOR HANDLING VISCOUS MATERIALS Filed May 24, 1954- 5 Shee'ts-Sheet 1 INVENTOP F. P. NEBEL ROTARY PUMP FOR HANDLING VISCOUS' MATERIALS June 18, 1957 5 Sheets-Sheet 2 Filed May 24, l954 M Q, 7 V 1 m A d n M W W/ W wrewra/P June 18, 1957 F. P. NEBEL ROTARY PUMP FOR HANDLING VISCOUS MATERIALS 5 Sheets-Sheet 3 Filed May 24. 1954 R m M m w F/ V a W yi7/ii F. P. NEBEL 2,796,030

ROTARY PUMP FOR HANDLING vIscous MATERIALS June 18, 1957 5 Sheets-Sheet 4 Filed May 24. 1954*- INVENTOP 4M June 18, 1957 F. P. NEBEL 2,796,030

ROTARY PUMP FOR HANDLING VISCOUS MATERIALS Filed May 24. 1954* 5 Sheets-Sheet 5 A WW United State Patmt ROTARY PUMP FOR HANDLING VISCOUS MATERIALS Franz Philip Nebel, Nurnberg, Germany Application May 24, 1954, Serial No. 431,951

Claims priority, application Germany May 29, 1953 20 Claims. (Cl. 103-124) The invention relates to a rotary pump for handling viscous materials, wherein a positively controlled oscillating abutment follows the outline of the impeller.

Rotary pumps of a Wide variety of types are known. All previously known rotary pumps are affected with a serious disadvantage, that of undue vibration. This is not very troublesome at low speeds of the impeller in such pumps. However, such pumps will not tolerate very high impeller speeds without damage to themselves and excessive percussion of the surroundings. At the same time, in order for the efliciency of such pumps to be high, a fairly high rotational speed is often required. There have been considerable efforts to achieve smooth operation at high rotational speeds. Heretofore, however, these attempts have failed because it was believed that the difiiculties in question could be overcome by simply improving the control of the oscillating member; whereas this was without effect on the smoothness of operation of the pump. The underlying cause of the trouble has not previously been recognized. The defect that has actually prevented the achievement of high impeller speeds in known pumps consists in the shape of the oscillating member; in the transverse wearplate, provided with a sharp or rounded edge and connected with the oscillating member; and in the placement and movement of the oscillating member relative to the impeller, as well as the shape of the latter.

The present invention is addressed to the problem of providing a rotary pump in which these defectsare eliminated.

This problem is solved substantially in thatthe oscillating member is pivoted and provided with a non-rotating cylindrical contact element wiping the surface of the impeller, the center of which element describes a circular arc, whereas its positions relative to the revolving impeller trace at Well-rounded curve determining a still more rounded track for the cams actuated in conjunction with the oscillating abutment. Another feature of the inventionconsists in that the tangent to the circle described by the impeller and the secant surface of the impeller formv an angle such that the wear part of the oscillating abutment will pass only away from the tip of the impeller along the surface in line with the apex, as the impeller revolves. A. further feature consists in that the surface and the tangent form an angle of such magnitude that the accelerations and decelerations of the inertia forces acting on the control of the oscillating. member, due to the oscillating movements of the latter and dependent an. the speed of the pump, are kept within allowablelimits; that is, the magnitude of the angle depends on.v the rotational speed, and mustnot exceed 100. Still another feature consists in that the radius R of the oscillating abutment is intermediate between R1+R1/3 and R1/ 2, where R1 is the distance from the center of the impeller shaft to the center of the pivot of the abutment.

A preferred embodiment of the control mechanism is characterized in that two adjacent parallel rollers mounted on the same or on separate lever arms positively control the oscillating abutment, one roller following the outside track and the other the inside track of the same or of separate cams. Another feature consists in that the roller lever, rigidly connected with the oscillating abutment by a shaft, being mounted e. g. on the shaft of the abutment itself, preferably by means of a forked member fixed on the shaft and two set-screws, is fixable and displaceable in either direction in order to permit adjustment of the desired clearance between impeller and abutment.

A preferred attachment of the cams is characterized in that the cams are fixably mounted, preferably on the cam and/ or impeller shaft, and adjustable e. g. by means of stationary forked members and set-screws. A preferred means of damping the inertia forces of the oscillating abutment is characterized in that counterweights are provided to balance the inertia forces of the abutment, e. g. by providing the abutment shaft with a crank to drive a flywheel with counterweight by means of a connecting rod. A variant consists in that a counterweight is provided on an auxiliary shaft bearing the cams. A further feature of the invention consists in that the impeller bears two rotating side plates integral therewith. Another feature consists in that the cover of the pump housing is held down on the housing by a closure means, for example a bridge with a pressure screw, for ready removability, and sealed with a gasket. A further feature consists in that the liner in the interior of the pump is attached by means of pins for ease of replacement. In a preferred embodiment of the pump housing, the latter is provided with an opening on the suction side, closed off with a readily removable cover, e. g. held in place only by a lever and counterweight. Finally, an additional feature consists in that the pump system and the cam or drive system each constitute a separate subassembly but are mounted on a common baseplate, so that the pump alone can be replaced without interfering with the cam or drive system.

In a pump according to the present invention, the oscillating abutment is made to follow a well-rounded curve adapted to the outline of the impeller. The pump is of extremely simple construction, and can be opened quickly for convenient access in a small number of operations. The liner in the housing for contact with the impeller can be readily and rapidly replaced with the aid of its pin mounting. The counterweights provided in the mechanism of the oscillating abutment compensate the inertia forces, so that the pump according to the present invention is free from excessive vibration. The side plates revolving with the impeller keep the abutment from working into the side packing.

Some embodiments of the invention are illustrated, by way of example and not of limitation, in the accompanying drawing, wherein:

Fig. 1 shows a front view of a rotary pump according to the invention, in median longitudinal section;

Fig. I shows a side view ofthe same, likewise in section;-

Fig. 3 shows the control system, with the pump housing in section;

Fig. 4 shows a diagram of the control system;

Fig. 5 shows another embodiment of the control system, as viewed at V in Fig. 6;

Fig. 6 shows the same embodiment in side view and partial section;

Fig. 7 shows a detail VII of Fig. 6;

Fig. 8 shows a detail VIII of Fig. 9;

Fig. 9 shows a view of TX in Fig. 6;

Figs. 10 and 11 schematically show additional embodiments of the control system.

In a pump housing 1, an impeller 3 is rotatably mounted and driven by a shaft 2. The surface of the impeller 3 is wiped by an oscillating abutment 4, maintaining a seal in known manner between the suction and pressure sides. The abutment 4 is fitted with a nonrotating cylindrical wear member 5 attached by means of screws 6. The housing 1 is fitted with a readily removable liner 7 attached by means of pins 8. The angle 11 formed by the tangent 9 and the surface 10 is such that the wear member 5 will move relative to the surface 10 in the direction of the arrow x only, namely away from the tip 13. The radius R of the oscillating abutment 4 is intermediate between the values The impeller 3 has revolving side plates 14 integrally attached to it. The housing 1 has a cover 15 which, being held against the housing 1 by means of a screw 17 in a bridge 16 attached to the housing, seals the housing 1 with the aid of a packing insert 18.

An opening provided on the suction side of the housing 1 is closed off with a cover 19 held tight against the opening with the aid of a lever 22 hearing a counterweight 21.

The oscillating abutment 4 (see Fig. 3) is controlled by means of earns 23, 24 fixed on the impeller shaft 2 and acting upon followers 26, 27 mounted forkwise on the abutment shaft 25. As Fig. 4 shows, one of the followers 26, 27 is always in contact with the corresponding cam 23, 24. The dot and dash line surrounding the impeller 3 in Fig. 1 shows the resulting well-rounded path of the center of the wear part 5 relative to the surface of the revolving impeller, drawn uniformly equidistant from the latter. In Figs. 5-9, there are two parallel cam rollers 28, 29, the roller 28 following the inner track of a cam 31 and roller 29 the outer track of a cam 32. The rollers 28, 29 are fixably mounted on a shaft 25, and adjustably attached to a fork 34 by means of set-screws 33. The cams 31, 32 are likewise fixably mounted on the shaft 2, and attached with set-screws 35 to forks 36 so that the cams 31, 32 can be aligned with the rollers 28, 29, and vice versa. Fig. 10 shows the arrangement of a lever arm 37 on the oscillating abutment 4, which lever arm is connected by a connecting rod 38 to a flywheel with counterweight 39, serving to balance the inertia forces of the oscillating abutment 4. In Fig. 11, the inertia forces of the oscillating abutment 4 are balanced by means of a counterweight 43 provided on an auxiliary shaft 42 hearing the cams 41.

What I claim is:

l. A rotary pump for handling viscous materials, comprising an impeller, a shaft for mounting said impeller, a positively controlled oscillating abutment wiping the surface of said impeller, a pivot for mounting said abutment, a non-rotating cylindrical wear member. removably attached to said abutment, and a plurality of controlling cams driven in conjunction with said abutment,

and

said abutment having a radius R lying between a in 2 and R1 3 wherein R1 stands for the distance from the center of said impeller-shaft to the center of the pivot of said abutment, the radius of said wear member and the radius R1 being at the minimum ratio of about 1:17, wherein a tangent, drawn to the circle described by the impeller during rotation, and a secant surface of said impeller form an angle which is maximally and is so adjusted, depending on the rotational speed of the pump and the viscosity of the material handled, that the wear member on the oscillating abutment will pass in the direction away from the apex of said angle along the surface line of the impeller following the revolving impeller, said cams being fixed on the impeller shaft and acting upon followers mounted on the abutment shaft and provided with counterweights.

2. A rotary pump according to claim 1, wherein the control cams are co-acting with two control rollers which follow the contour of said control cams.

3. A rotary pump according to claim 2, wherein the control rollers are mounted on a common control lever arm.

4. A rotary pump according to claim 2, wherein the control rollers are mounted each on a separate control lever arm.

5. A rotary pump according to claim 2, wherein each control lever is associated with one control cam.

6. A rotary pump according to claim 2, wherein one of the control cam has an inside track and the other of the control cams has an outside track for said control rollers.

7. A rotary pump according to claim 2, wherein both control cams have outside tracks for the control rollers.

8. A rotary pump according to claim 2, wherein both control rollers are associated with a common control cam.

9. A rotary pump according to claim 4, wherein said control levers are fixedly mounted on a shaft rigidly connected to the abutment shaft.

10. A rotary pump according to claim 4, wherein said control levers are secured on the abutment shaft.

11. A rotary pump according to claim 10, wherein the roller-supporting levers are mounted on the abutment shaft by means of a forked member adjustable with set screws in two directions.

12. A rotary pump according to claim 2, wherein the controlling cams are secured to the impeller shaft.

13. A rotary pump according to claim 12, wherein forked members are provided for securing the control cams on the impeller shaft, said forked members having set screws for making said mounting adjustable.

14. A rotary pump according to claim 1, wherein the abutment shaft is provided with a lever arm associated with a connecting arm for connecting a flywheel with counterweight to said shaft, serving to balance the inertia forces of said oscillating abutment.

15. A rotary pump according to claim 1, wherein an auxiliaryshaft is provided, a cam mounted thereon, a counterweight on said auxiliary shaft, and connecting means for driving said cam from said abutment pivot.

16. A rotary pump according to claim 1, wherein said impeller has two lateral plates secured thereto and rotating therewith.

17. A rotary pump according to claim 1, which includes a pump housing, cover means for closing said housing, and readily removable means for securing said cover means in air-tight manner on said housing, said lastmentioned means comprising a bridge-shaped member, pressure screws for fastening the same, and a gasket for interposition between the cover means and the pump housing.

18. A rotary pump according to claim 1 which includes a pump housing, an exchangeable lining therefor, and pins for fastening the same.

19. A rotary pump according to claim 1, including a pump housing having an opening on the suction side, a readily removable cover for closing the same, and a lever with a counterweight for holding the cover in place.

20. A rotary pump according to claim 1, wherein the 5 pump system and the cam or drive system each constitutes 1,509,051 McBryde Sept. 16, 1924 a separate subassembly mounted on a common base plate 2,363,961 Hart Nov. 28, 1944 but capable of individual replacement without interfer- FOREIGN PATENTS ence with the other system.

25,849 France Feb. 20, 1923 References Cited in the file of this patent 5 i getheflands 1 9 rance ug.

UNITED STATES PATENTS 170,171 Austria Jan. 25, 1952 297,478 Warfh 22, 1884 270,335 Switzerland Nov. 16, 1950 506,533 Nasl Oct 10, 1893 641,390 Great Britain Aug. 9, 1950 9 tt M y 18, 1909 10 708,73 France May 4, 1931

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