US3005597A

US3005597A - Pump for fluids containing solids

Info

Publication number: US3005597A
Application number: US725141A
Authority: US
Inventors: Neidl Georg
Original assignee: Individual
Current assignee: Individual
Priority date: 1957-04-11
Filing date: 1958-03-31
Publication date: 1961-10-24
Anticipated expiration: 1978-10-24

Description

Oct. 24, 1961 G. Nl-:IDL

PUMP FOR mums CONTAINING soLIDs Filed March 3l, 1958 3,005,597 PUMP FUR FLUmS CONTAINING SOLIDS Georg Neidl, 108 Schonfliesser Strasse, Berlin- Frohnau, Germany Filed Mar. 31, 1958, Ser. No. 725,141 Claims priority, application Germany Apr. 11, 1957 1i) Claims. (Cl. 241-255) This invention relates to a pump for uids containing solids, and more particularly to a rotary pump for the conveyance of fluids, such as effluents, thick pulps and the like.

Rotary pumps for the conveyance of effluents, thick pulps and the like are known, in which the pump body is made in the form of a disc arranged at an inclination to the shaft axis and rotating within a stationary casing, the supply branch being positioned in the axis of the casing, while the delivery branch lies at the periphery of the casing. According to a further proposal teeth, serrations or similar protuberances are provided at the periphery of the pump body with the object of exerting a tearing eiTect on impurities, more especially textiles, which are carried along by the lluid to be conveyed.

.By this means it was intended to prevent any clogging of the pump.

It has been found, however, that these known pumps do not always fully satisfy the requirements, more particularly, where it is a problem of dealing with highly resistant impurities, such as chemical libres. According to the invention, particularly good results are obtained, by forming the pump body as a disc fixed obliquely to the shaft in its axis and providing it at the same periphery with teeth, serrations, projections or depressions in such a manner that these teeth and the like engage in grooves provided in the internal surface of the pump casing. The disc preferably is of an elliptical form,

such that the clearance between the teeth, serrations, projections or depressions at the outer periphery of the disc and the grooves at the inner periphery of the pump casing is the same at all points and in all positions of the disc. This clearance may also be kept slight and even reduced in certain circumstances to such an extent that the elliptical disc with its teeth, serrations, projections and depressions is in substantial contact all over in the cylindrical pump casing, so there is no longer any clearance.

For technical reasons of manufacture and for reasons of simple floating assembly it may be of advantage to provide the groove-like depressions in the inner surface of a two-part, axially divided bushing which is inserted axially into the one-piece pump casing. The disc may be made with a plane surface or be spatially curved or, a pump body of any other form may be used, which must be such, however, that at least portions of the pump body will perform tumbler or wobbling motions and that the peripheral parts are provided with teeth, serrations, projections or recesses, which engage in corresponding grooves at the periphery of the casing.

Finally, it may be of advantage to cut away the elliptical disc at both narrow sides in such manner with respect to the disc surface that each cut surface after the disc body has been mounted in the pump casing, is at the same distance with respect to the inner surfaces of the two casing covers in all positions of the pump over the whole surface.

lThis formation of the disc body possesses on the one hand technical manufacturing advantages, in that the teeth, etc. need only be carried out as far as these side surfaces. For, should the teeth, etc. in the case of a pure ellipse be carried out right up to the main axis of the ellipse, diiiiculties would be experienced, as the tooth profile would have to be given a shape no longer l arent capable of being carried out, while, on the other hand, the cutting away of the ellipse at the two narrow sides has the advantage, that the pump disc can be mounted not only against the inner end surface of the two casing covers, but can be allowed to run round, so that should this clearance be made very small or even allowed to drop to zero-tight, jointing between the cut away surfaces of the pump body and the inner surfaces of the casing covers is brought about.

This may be of special importance, when eiiluents are to be conveyed, which contain considerable accumulations of textiles, more particularly chemical fibres. Such an eiiluent is drawn in by suction through the inow branch into the pump in the case of a pump disc supported in a floating or overhang inclined manner on the side facing away from the shaft. The rags contained in the eiliuent will then be thoroughly torn apart and ground up between the teeth of the pump body and the grooves of the pump casing, whereupon they will together with the water be conveyed away through the outflow branch.

The tight jointing between the cut away inclined surfaces and the inner end surfaces of the casing cover has the advantage, that no larger parts of the rags will pass into that space in the interior of the casing, in which the shaft is contained. This is of importance for the reason, that these rags would wrap themselves'round the shaft and thereby choke the pump.

Instead of a single disc, a plurality of discs may be provided which are mounted obliquely to the pump shaft on the latter, and which are provided with projections, depressions or proles and engage in corresponding grooves at the inner periphery of the casing or of the casing bushing.

The invention is illustrated yby the constructional examples in the accompanying drawings, in which:

FIGURE l is a view in elevation and partly in crosssection of a pump embodying the present invention;

FIGURE 2 a partial axial section on a larger scale through the pump at the location, where the disc teeth engage in the grooves of the pump casing,

FIGURE 3 is an elevational view showing the pump body removed from the pump and clamped in the expending chuck of a lathe, for illustrating the production of the toothing,

FIGURE 4 shows another constructional form of the pump in axial section with a spatially curved pump disc,

FIGURE 5 shows yet another constructional form of the pump in axial section with two pump discs crossing one another,

FIGURE 6 shows another constructional form of the pump in axial section with segment-like cut away parts at the two narrow sides of the elliptical pump body,

FIGURE 7 a plan view of the disc-shaped pump body of FIGURE 6, and

FIGURE 8 is a modification of teeth and groove arrangement of FIGURE 2.

According to the constructional form of FIGURES 1 to 3, a pump shaft 1 is floatingly supported in a bearing 2 and is provided wit-h a stuffing box 3. To enlarged end 4 of the pump shaft, the above-described pump disc 5 is fixed obliquely by means of counter-sunk screws, so that the surface of the pump disc 5 remains smooth and nothing can adhere thereto. At the outer periphery of the pump disc 5, teeth 6 are cut by turning, and which teeth engage in grooves 7 of Vserrated or otherwise depressed proiile. These grooves are cut at the inner periphery of a bushing 8 which is pushed into cylindrical casing 9 and lixed with its flange 10 by screws 11 to flange 12 of the casing 9. At the inner periphery, the bushing 8 is provided with a cut away area 13 which opens into a corresponding recess in the casing 9, which recess communicates with a delivery branch 14. An

Y v inlet branch 15 is connected by means of a flange 16 with the flange 12 of the casing 9.

The disc which is of elliptical shape, when viewed perpendicularly in the direction of the arrow A is so formed as an ellipse that, after being mounted in the pump, it appears circular, in the axial projection that is in the direction of the arrow B. This disc 5 is so made, as regards its dimensions, that its teeth, serrations, projections or depressions engage with clearance (compare FIGURE 2) in the grooves 7 of the bushing.

Each point of the disc S travels during the rotary mo tion of the disc along circular paths with respect to the Shaft 1, assuming the viewer to be on the disc 5. On the other hand, each point of the disc 5 performs, when viewed from the casing inlet, not only rotary motions, but also oscillatory motions. It follows, that during the rotary motion of the disc 5, a certain thrust effect towards the left and right will be exerted within the casing 9, which, however, is greatly exceeded by the centrifugal force of the fluid to be conveyed, so that the conveyed material enters from the inlet'branch 15 into the casing, being forced out through the delivery branch 14.

From the relative points of view of the aforesaid observer, assuming him to be on the disc 5 or on the casing 9, it follows, that the grooves 7 do not lie helically in the bushing 8, but are arranged concentrically to one another.

For illustrating the motions, it should be pointed out, that in FIGURE l, the disc 5 is shown in plan view. Assuming, however, that the disc 5 is turned out of the position of FIGURE 1 through 90, according to the direction of rotation backwards or forwards Vit would be seen, that the disc 5 will then appear in FIGURE l with groove within the bushing 8 of the pump, the cutting Ytool 21 is brought into the position shown by dotted a twisted surface, so that the disc will, as it were, shovel the conveyed material out of the pump towards theA delivery branch 1-4.

Through the thrust referred to above Ycertain losses may occur, it is true, should the disc 5, viewed in the direction of the arrow A, be made not elliptical, but circular, in which case the disc, viewed in the direction of the arrow B would appear as an ellipse. These losses would be due to the circumstance, that between the periphery of the discv 5 and the inner surface of the casing a substantially greater distance would be created at thev location of the minor axis of the ellipse thanin the region of its major axis. For ythis reason it will be of advantage to make the disc of such a shape that thedistance between its periphery and the inner surface of the casing is the same at all locations. 'Ihis will be brought about through the disc 5 being made elliptical in the direction of the arrow A in such manner that, viewed in the direction of the arrow B it will appear circular.

For the assembly of the pump it is necessary to make the bushing 8 in two parts in the axial section, so that, as shown in FIGURE 1, a joint 19 is formed. The assembly will then be carried out in the following manner: After the shaft has been mounted in the bearing 2 and after the cylindrical Vcasing part 9 has been hanged to the cover 17 on the machine frame 18, the two halves of the bushing 18 are placed outside the casing round the disc 5V and the disc together with the two bushing halves 8 are placed into the casing 9, until the disc 5 'Y strikes against the enlarged end 4 of the shaft 1. Thereupon the disc 5 is secured by means of the screws onto the enlarged end 4 of the shaft 1. Y

The screws 11 of the bushing 8 are then tightened and, finally, the inlet branch 15 is screwed to the lian-ge r12, of the casing.

For producing the teeth for the disc 5, the shaft 1 of the pump with the secured disc 5 is clamped in jaws 20 of the chuck of a lathe (FIGURE 3)Y and by means of a tool 2,1, the profile of which corresponds to the gap between the teeth to be produced, starting at one end of the disc, the first teeth with corresponding profile is cut.

Thereupon, corresponding to the distance apart of the 75 34.

Y 15 (FIGURE l).

' pump body having blading or other profiling,

lines in FIGURE 3 and, by bringing the tool to bear the second tooth depression is cut in at two oppositely ydisposed places into the disc. In this way the tool 21 is displaced step by step over the whole width of the disc, whereby the latter is provided with teeth over the entire periphery, which are so formed that after being mounted in the casing, they will engage in the corresponding -grooves of the bushing 8.

The advantage of the present invention consists in giving the disc an elliptical shape for the purpose of avoiding unnecessary lateral thrusts and turbulences, and in effectively shutting off the end of the shaft 1 which projects into the casing, with respect to the inlet branch This is due to the fact that the teeth 6 of the disc S are in engagement during the rotary motions permanently with the grooves 7 of the bushing 8, so that the textile impurities entering through the inlet branch 15 into the left hand part of the casing with the efuent can never enter those parts of the casing in which there is a portion of the shaft, without these textile pieces not having been previously iinally shredded by the teeth 46 of the disc. This tine tearing up is produced lmainly by the cutter-like coaction of the teeth 6 with the grooves 7. Hence, the wrapping of textiles round the pump shaft, which is frequently observed in the case of the known pumps and necessarily leads to the jamming of the pump, can never occur.

Nevertheless, the side of the disc, shown to the 'right in FIGURE 1, also operates with a shovel action. Assuming the disc 5 to be turned through 180 with respect to the position shown in FIGURE 1 (see dash-line representation), it will be seen at once, that the delivery branch 14 is now in communication with the right hand side of the disc, that is to say, this half of the casing as well will ll up with conveyed material which will be shovelled towards the ydelivery branch 14.

It is of advantage, even if not absolutely necessary, to leave some clearance between the groove 7 of the casing bushing, which is tooth-Shaped in cross-section, and the disc teeth 6, to ensure soft running of the pump. Tests have shown, that the teeth of the disc satisfactorily tear up and disintegrate the rags and textiles within the grooves 7, even when there is clearance. In many cases it is even found to be of advantage to have a considerable clearance between the teeth 6 and 7, more particularly, for instance, when slices of sugar beet are to be pumped, where an all too great disintegration is not desirable.

In a modified form of the invention, disc 22 may be made arcuate (as in FIGURE 4). For the rest, however, the disc is made elliptical at its periphery in such a manner that, viewed in the direction of the arrow C, the periphery Vof the disc is circular, so that the disc teeth will engage in the grooves of the casing bushing. According to the constructional lform of FIGURE 5 two discs 23 which cross and penetrate one another can be fixed obliquely on the pump shaft. Each disc has peripheral teeth which engage in the grooves of the casing bushing.

The pump bodies may have continuous archings or depressions, having raised places in themselves or the it being only of importance, that the peripheral parts of the pump body shall engage in the teeth in the interior of the casing. Finally, the pump body may be provided with perforanons, in order to reduce the thrust, which is of special advantage in the case of semi fluid conveyed materials.

According to the constructional form of FIGURES 6 and 7 the pump disc 24 is cut away at both narrow sldes 29, so that plane section surfaces 30 are formed. These section surfaces 36 are so placed with respect to the surface of the pump body disc 24 that they extend parallel to the inner surfaces 31, 32 of the two casing covers 33, YAS Will be ,Seen from FIGURE 6, there is clearance between the

surfaces

30, 31 and 36, 32 namely a clearance 35. If required, this clearance may be brought down to zero, so that a more or less good tight jointing between the surface 36 and the inner surfaces 31, 32 of the

covers

33, 34 of the pump casing is ensured.

This tight jointing has the advantage, that, in the case or water heavily permeated with rags, which penetrates through the inlet branch 44 into the material of the pump, these rags are extensively torn up by the teeth of the disc body and the grooves in the interior of the casing, without the possibility of larger pieces of rag getting into that part of the casing, which contains the shaft 43, so that there is also no danger of rags becoming wrapped round this shaft.

The area 36 shown white in FTGURE 6 shows the open-l. ing in the bushing, through which the fluid passes into the delivery branch shown at the top.

According to the invention it is necessary to so arrange the disc 24 at an angle to the pump shaft 43 that the two section services at the narrow sides 29 of the disc 24 will be directed to the inner surfaces 31, 32 of the two casing covers 33, 34. Only in this case is the cutting away of the pump disc 24 at the two narrow sides 29 of any use. If the disc 24 were to be placed at a considerably steeper angie to the shaft 43, the two section surfaces 30 would not be directed to the inner surfaces 31, 32 of the two casing covers 33, 35:, but directly to the grooved bushing 45. ln that case the disc would not actually be cut away, but have to be formed in the direction A of FIGURE l as a full ellipse and be provided with teeth right up to the ends of the major ellipse axis.

The angle of inclination between the disc 24 and the shaft axis 43 should preferably be made such that the left hand section 30 of the disc, as will be seen in FIGURE 6, as it were encircles the internal diameter of the suction branch 44, without entering this internal diameter. Otherwise, the conveyed material entering the pump through the suction branch would irnpinge on the section surface 30 of the disc 24, which would be of disadvantage. Through the choice of a denite angle of inclination, as described above, a favourable efficiency of the machine is also obtained.

According to the invention, the teeth 6 may also be formed that they will not end in a point to the outside, but will appear flattened off at the upper ends in accordance with illustration of FIGURE 2, thus no longer having cutting edges which are sharp at the top. Analogously, the grooves 7 are, as shown in FIGURE 2, not made triangular in cross-section, but have the form of a section through a trapezoidal thread. Of course, not screwthreads, but only parallel grooves are cut in the bushing 8.

This kind of formation of the teeth and grooves has the great advantage from the manufacturing point of View, in that the pump disc 5 can readily be made together with the teeth 6 and the bush 8 with the grooves 7 by casting rather than by turning. Subsequent tooling will then be entirely superfluous, when a suitable amount of clearance is left more particularly between the teeth 6 and the grooves 7. In spite of this the tearing effect is hmdly reduced at all, because the teeth, viewed in opposition to the direction of rotation, operate with their front edge and not with their cutter-like points'.

I claim:

1. A rotary pump for conveying fluids such as effluents,

thick pulps and like materials, comprising a cylindrical casing having an inlet and an outlet for the material being conveyed, a shaft extending at least partially into the CII casing concentric to the axis of the casing, a pump body supported by the shaft obliquely to the axis of the shaft, said pump body being defined as an elliptical disc having peripheral teeth-like components along at least two edges thereof, and the inner peripheryof the cylindrical casing being provided with grooves of corresponding axial section with which said teeth-like projections of the disc cooperate so that on rotation of the shaft a combined rotary and oscillatory movement is imparted to the elliptical disc to scoop the material entering the inlet to the outlet while the teeth-like components and grooves coact to disintegrate any solid matter in the material, thereby preventing such matter from engaging and imparing the Arotation of the shaft.

2. A rotary pump as claimed in claim 1, in which the teeth-like components of the disc and the grooves of the casing are so formed as to provide a clearance between such teeth-like components and groove.

3. A rotary pump as claimed in claim 1, in which said grooves are provided in a two-part bushing insertable axially into the casing.

4. A rotary pump as claimed in claim 1, in which said pump body is defined as a spatially curved disc.

5. A rotary pump as claimed in claim 1, in which the narrow sides of said disc are formed as plane surfaces and said casing is provided with end walls having plane faces whereby during rotation of the pump body the same degree of clearance exists betwen the plane surfaces of the disc and the plane faces of the end walls in each position of the pump body during rotation.

6. A rotary pump as claimed in claim 5, in which the plane surfaces of the di-sc extend parallel to the plane faces of the end walls.

7. A rotary pump as claimed in claim 5, in which the clearance between the plane surfaces of the disc and the plane faces of the end walls is reduced to zero.

8. A rotary pump as claimed in claim l, further including at least one additional elliptical disc arranged perpendicularly to the rst-mentioned disc.

9. A rotary pump as claimed in claim 1, in which said grooves are arranged concentrically to one another.

10. A rotary pump as claimed in claim 1, in which the angle between the elliptical disc and the shaft is so selected that the peripheral portion of the disc facing the inlet during rotation of the disc describes a circle, said circle being greater than the inlet opening discharging into the casing.

vReferences Cited in the file of this patent UNITED STATES PATENTS 489,723 Titus Ian. 10, 1893 1,131,230 Giddings Mar. 9, 1915 1,697,202 Nagle Jan. l, 1929 1,980,589 Acree Nov. 13, 1934 2,336,798 Nash Dec. 14, 1943 2,501,275 Heller Mar. 2l, 1950 2,610,836 Clarke Sept. 16, 1952 2,718,012 Howe Sept. 20, 1955 FOREIGN PATENTS 19,579 Australia of 1934 183,980 Austria Dec. l0, 1955- 240,004 Germany Oct. 25, 1911 501,662 Germany July 5, 1930 819,346 Germany Oct. 31, 1951 932,556 Germany Sept. 5, 1955