US3481273A

US3481273A - Sanitary processing pumps

Info

Publication number: US3481273A
Application number: US708117A
Authority: US
Inventors: Bruno H Werra
Original assignee: Ladish Co
Current assignee: ATI Ladish Co Inc
Priority date: 1968-02-26
Filing date: 1968-02-26
Publication date: 1969-12-02
Anticipated expiration: 1986-12-02

Description

Dec. 2, 1969 B. A. WERRA 3,481,273

SANITARY PROCESSING PUMPS Filed Feb. 26, 1968 INVENTOR BRUNO H. WERRA ATTORNEYS United States Patent 3,481,273 SANITARY PROCESSING PUMPS Bruno H. Werra, Waukesha, Wis., assignor to Ladish C0., Cudahy, Wis., a corporation of Wisconsin Filed Feb. 26, 1968, Ser. No. 708,117 Int. Cl. F04d 1/00; F04b 21/00; F16j 15/42 US. Cl. 103-103 9 Claims ABSTRACT OF THE DISCLOSURE The hub of the impeller of a liquid pump, as well as a portion of the impeller shaft therebelow, rotate in a pocket in the base of the pump housing and are provided with circumferentially spaced grooves which are angled in a direction to cause flushing of the pocket and adjacent parts when the pump is in operation.

BACKGROUND OF THE INVENTION Field of the invention The present invention relates to liquid processing equip ment, and more particularly to a novel self-cleaning impeller hub arrangement for use in liquid food pumps and similar equipment having a pocket in which the impeller hu-b rotates.

Description of the prior art In milk blending pumps and other liquid food processing equipment it is necessary to thoroughly clean and sanitize said equipment at frequent regular intervals. Ordinarily the equipment is cleaned in place immediately after each processing operation with caustics, acids and sanitizers at elevated temperatures. In certain pumps, such as electrically-driven blending pumps, power-driven impeller assemblies have a recessed hub-receiving pocket and crevices between adjacent parts in the bottom of the pump housing within which milk or other matter becomes trapped and accumulates. With conventional arrangements said accumulated residue is not thoroughly flushed out from the crevices and pockets during the cleaning operation, with the result that subsequent food batches introduced into the processing pump may become contaminated thereby. This is not tolerable in the dairy and other liquid food processing industries wherein high sanitation standards must be rigidly maintained.

SUMMARY OF THE INVENTION The present invention provides an improved pump assembly for use in liquid food processing equipment and the like wherein the impeller hub and drive shaft are provided with novel circulation-creating means in the form of angularly-disposed, circumferentially-spaced grooves which function to forcibly flush the hub pocket. The result is that such pocket and adjacent parts are effectively purged, thereby promoting the complete sanitization of the device. I

Further objects of the present invention are to provide a novel self-cleaning impeller assembly for sanitary processing pumps or the like which is simple in design and operation, which is reliable in use, and which is otherwise patricularly well adapted for its intended purposes.

Brief description of the drawing In the accompanying drawing, wherein the same reference numerals designate the same parts in all of the views:

FIG. 1 is a side elevational and partial vertical sectional view of a processing pump connected to the bottom of a liquid tank;

FIG. 2 is a top plan view of the stub shaft featured in the invention; and

3,481,273 Patented Dec. 2, 1969 FIG. 3 is a top plan view of the impeller with the upper end of the stub shaft fitted in the impeller opening.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now more particulalry to FIG. 1 of the drawing, the numeral 10 designates a tank or container of the type commonly used in dairies in conjunction with a milk processing pump, the pump housing 11 being mounted below and having a top opening communicating with a bottom opening 9 of said container, as shown. As is usually required in the dairy and food processing industry, said tank 10 and pump housing 11 are formed of stainless steel or equally corrosion resistant material,

as are all of the other structural components hereinafter described, in order to provide maximum sanitation.

The pump housing 11 is generally cylindrical in form and has a discharge opening 12 in one side thereof to which a conduit or the like can be attached. Said pump unit is mounted on a suitable support or adapter 13 above or adjacent to an electric motor 14, there being a clamping ring 15 or the like securing the pump housing in position on the support 13. Projecting upwardly or outwardly from the motor is a drive shaft 16. Fitted over the upper or outer end of said drive shaft 16 is a stub shaft 17, there being suitable slot and interfitting key means 18, 18 drivably connecting said stub shaft 17 to said drive shaft.

Referring still to FIG. 1, the stub shaft 17 includes an intermediate portion 21 of reduced diameter, and projecting thereabove is a portion 23 of still smaller diameter, the latter portion being rotatably joumaled in an opening in the bottom of the plate 26.

Surrounding the intermediate portion 21 of the stub shaft is a coil spring 22 which bears against the underside of an annular cup-shaped retainer 25 for a carbonring 24, there being a rubber O-ring 24 within the carbon ring. This provides a seal around said stub shaft and the carbon ring is urged upwardly by the spring 22 into sealing engagement with the underside of the bottom plate 26 of the pump housing. Said bottom plate 26 has a central pocket 26 to accommodate the hub of the impeller, as will be described hereinafter, and the opening within which the stub shaft portion 23 is journaled is formed in the bottom of said pocket 26'. As will be hereinafter described in greater detail, pumping means such as a plurality of circumferentially spaced, angled grooves 29 are formed in the periphery of said stub shaft portion 23, said grooves extending upwardly at an angle from a point immediately above the aforementioned O-ring 24 and communicating with the shoulder 40 at the top of said shaft portion 23 (see FIG. 2.). Four of said grooves 29 are used in the illustrated embodiment of the invention, but the invention is not to be limited in this respect.

Formed integrally with and projecting upwardly from the stub shaft portion 23 is an upper stub shaft portion 27 of less size and which projects into the interior of pump housing 11. As best appears in FIG. 2, said upwardly-projecting stub shaft portion 27 is substantially square in cross section and has beveled corners as at 28. The aforementioned grooves 29 in the stub portion 23 open immediately adjacent the lower ends of said beveled corners, the function of which will be hereafter seen.

Fitted on the squared uppermost portion 27 of the stub shaft 17, and seated on the shoulder 40 provided by the enlarged stub shaft portion 23 therebelow, is the hub 31 of the impeller 34, the aforementioned pocket 26' in the bottom 26 of the pump housing being of greater diameter than said hub to loosely accommodate it. Said impeller hub 31 has a square opening 32 (FIG. 3) adapted to receive the squared stub shaft portion 27, there being vertical passageways 41 adjacent the beveled corners 28. Suitable means, such as the transverse pin 30, insertable into a bore in the upper end of the stub shaft portion 27 removably retains the impeller in assembled position.

As is apparent from the above, when the impeller is driven by the motor 14- the lower portion of the hub is rotated in the pocket 26.

As is shown in FIGS. 1 and 3 of the drawing, the periphery of the impeller hub 31 is provided with pumping means such as circumferentially-spaced, angularly-disposed grooves 33, the purpose of which will be hereinafter described.

The blades of the impeller 34 project from the upper portion only of the hub 31. Said blades are shaped to carry out the mixing or propelling action of the processing pump, as is well known in the art. The above-described angular hub grooves 33 communicate with the top of the hub, as shown, there being, in the illustrated embodiment, three of said grooves, one between each pair of impeller blades. Preferably, said grooves 33 are disposed at an angle of about 55 from the horizontal.

In the operation of a milk processing pump of the type illustrated, milk in the tank fills the pump housing 11, and when the motor is operated to drive the shaft 16 and stub shaft 17, the impeller 34 is rotated to mix, blend, or move said milk as desired.

As heretofore mentioned, in conventional processing pumps a quantity of the milk or other liquid being processed finds its way into the pocket 26' in the bottom 26 of the pump housing, and into any adjacent crevices and between the stub shaft 17 and the impeller hub 31. After the milk is drained from the system there are trapped milk particles and semisolids forming a residue coating which is difficult to flush out when the apparatus is periodically flushed with cleaning solution, with the result that said food particles accumulate and may contaminate subsequent batches of milk or other liquid product introduced into said unit.

In addition, in conventional pumps caustic sanitizers used in the flush cleaning of said blending apparatus may remain in the pocket 26 and in crevices between adjacent parts and this is obviously undesirable. It is to eliminate the accumulation of such contaminating matter from the pockets and crevices in the pump housing that the novel hub and

stub shaft grooves

33 and 29 are provided.

As viewed in FIGS. 2 and 3 of the drawing, the stub shaft portion 17 and interconnected impeller hub 31 are designed to rotate in a counterclockwise direction, as indicated by the directional arrows in FIG. 3, and the

angled grooves

33 and 29 in said members are biased upwardly and rearwardly relative to said direction of rotation. As a result, when said impeller and stub shaft assembly is rotated during use as well as during a flushing operation said grooves act as pumps to flush out any milk particles or other residue from the adjacent pocket and crevices, said matter being urged upwardly in said angled grooves and being discharged from the tops of said grooves into the housing 11, where the material is evacuated through the discharge opening 12 by the flushing solution. The result is that during normal use milk is always kept agitated in the pocket 26' so there is less likelihood of it collecting in hardened form. Also when the system is being flushed with a cleaning solution the pocket 26' and crevices between adjacent parts are effectively purged of any contaminating matter which may have remained after draining, and the complete sanitization of said unit is promoted.

In addition to the accumulation of foreign matter in the impeller hub cavity 26', it has been found that in conventional pumps milk paricles or other foreign matter find their way into the impeller hub opening 32. The corners 28 of the stub shaft portion 27 are beveled, thereby creating corner recesses 41 within which food particles and the like can accumulate. The arrangement of the angular grooves 29 with their upper ends opening immediately adjacent said beveled shaft corners 28, however, as

shown in FIG. 2, results in direct communication between said circulation-creating grooves and the corners 41, and any food or the like accumulated therein is effectively flushed from the hub opening, and there is also agitation near the hole for the retainer pin 32.

From the foregoing detailed description it will be seen that the present invention provides a novel and improved impeller assembly for use in sanitary blending or processing pumps and the like which is designed to prevent food or other matter from being trapped and accumulating in pockets and crevices in said pump, and possibly contaminating subsequent food products introduced therein. Said novel, self-cleaning pump assembly is simple in design and operation, is reliable in use, and is otherwise particularly well adapted for its intended purposes.

It is to be understood that while the present invention has been described herein as being particularly well suited for use in a milk blending or processing pump of the type commonly used in dairies, the improved sanitary pump assembly featured in the present invention can also be advantageously utilized in other types of liquid processing equipment, as well as in pumps used in other industries where a similar problem is present. It is to be understood, too, that while a preferred embodiment of the present invention has been illustrated and described herein, variations or modified forms thereof may occur to those skilled in the art. For example, the object of the invention may be accomplished either by the grooves 29 or by the grooves 33, but by having both sets of grooves the action is more efficient. Also the invention is useful in either vertically or horizontally disposed pumps. What is intended to be covered herein is not only the illustrated embodiment of the invention but also any and all variations or modifications thereof as may come within the spirit of said invention, and within the scope of the following claims.

What I claim is:

1. In a liquid pump having a housing with a wall portion provided with a pocket, said pocket having a cylindrical wall and having a bottom, and said pump having an impeller mounted for rotation in said housing, said impeller including a hub having a cylindrical wall and having inner and outer end faces, the inner portion of said cylindrical wall of said hub and said inner end face being disposed in said pocket and another portion of said cylindrical wall projecting outwardly of the pocket and terminating in said outer end face, said impeller including blades supported by only the said portion of the hub which projects outwardly of the pocket, said cylindrical wall of the hub having a plurality of circumferentially spaced grooves extending at an oblique angle but in a generally axial direction with respect to the hub, a portion of the length of said grooves being out of the pocket and said grooves serving as pumping means positioned to act on liquid in the pocket to cause flushing thereof and adjacent parts when the impeller is rotated.

2. A liquid pump as claimed in claim 1 in which the hub is integral with the impeller.

3. A liquid pump as claimed in claim 1 in which the angled grooves have their lower ends communicating with the lower face of said hub portion within the pocket.

4. In a liquid pump having a housing with a wall portion provided with a pocket and having an impeller mounted for rotation in said housing, said impeller having a hub, and there being a drive shaft for the impeller, the improvement comprising rotatable parts in said pocket connected to said impeller for rotation therewith and including both a portion of the drive shaft for the impeller and the hub portion of the impeller, each of said portions having pumping means thereon positioned to act on liquid in said pocket to cause flushing of the pocket and adjacent parts when the impeller is rotated.

5. Apparatus as claimed in claim 4 in which the pumping means on each of said parts comprises circumferentially spaced angled grooves.

6. In a liquid pump having a housing with a wall portion provided with a pocket and having an impeller mounted for rotation in said housing, a drive shaft for the impeller which projects through said pocket and which has a rotatable part in said pocket having pumping means thereon positioned to act on liquid in said pocket to cause flushing of the pocket and adjacent parts when the impeller is rotated, the impeller end of the drive shaft being reduced and squared, and said impeller having a square hole to receive said squared end of the drive 10 shaft, and there being a shoulder between said part of the drive shaft which rotates in the pocket and the squared upper end of the drive shaft, which shoulder is located in the pocket, the pumping means being positioned to direct liquid into the hole of the impeller.

7. A liquid pump as claimed in claim 6 in which the pumping means comprises peripherally spaced angled grooves having upper ends at said shoulder to direct liquid into the hole of the impeller.

8. Apparatus as claimed in claim 6 in which the corners of the squared upper end of the drive shaft are beveled to provide corner passageways, and in which the pumping means is located at the lower ends of said passageways to flush the same,

9. Apparatus as claimed in claim 8 in which the pumping means is in the form of peripherally spaced angled grooves whose upper ends are located at the lower ends of the corner passageways.

References Cited UNITED STATES PATENTS 823,077 6/ 1906 Pitman. 1,504,658 8/1924 Ulmer. 1,791,547 2/1931 Yoder. 2,669,938 2/1954 LaBoor 103-115 FOREIGN PATENTS 618,598 12/ 1926 France. 325,930 3/1930 Great Britain. 312,362 2/ 1956 Switzerland.

HENRY F. RADUAZO, Primary Examiner U.S. Cl. X.R.