US1785354A - Hydraulic machine - Google Patents

Description

Dec. 16, 1930. F. LAwAczEcK 1,785,354

HYDRAULIC MACHINE Filed May 19,l 1926 2 Sheets-Sheet l INVENTOR HYDRAULI C MACHINE Filed May 19, 1926 2 Sheets-Sheet 2 Patented Dec. 16, 1930 FRANZ LAWACZECK, OF MUNICH, GERMANY, ASSIGNOR TO WORTHINGTON PUMPAND MACHINERY CORPORATION, OF NEW YO RK, N Y., A CORPORATION 0F VIRGINIA HYDRAULIC MACHINE Application led May 19, 1926, Serial No. 110,266, and in Germany January .19, 1926.

My invention relates to hydraulic machines and more especially to turbines, rotary pumps and the like. It is an object of my invention to provide means for creating f in' a machine of this type improvedconditions of iiow.

It is an` established fact that a definite peripheral velocity must be imparted to the whirling body of liquid in the machine and to the rotor in order to obtain an eicient exchange of energy, but the problem of axial velocity has not-yet been fully investigated, the only rule laid down so far being that the axial. velocity must be constant throughout the area of the suction pipe.

The bod of liquid on the opposite side of the rotor rom the suction pipe, that is, the body in front of the rotor in turbines, and at the rear of the rotor in pumps, constitutes a whirling iiow which carries a definite amount of kinetic and potential energy for a given machine and a given power input or output at the rotor. As a rule only thev potential energy is utilized and it is therefore desirable `to change-the kinetic energy of'this whirling flow into potential energy. Obviously this change should be brought about under conditions' of maximum eiiiciency, that is, substantially without loss. However, the change can only be effected under conditions of maximum eiiiciency if the iiow of the body of liquid is not disturbed in any way but the energy-carrying -components 'of the whirl are carried in a regular manne This condition is fulfilled according to this invention by so designing the casing of the machine that the clearance, that is, the radial distance between the water-contacting surfaces of its walls which control the flow of liquid on the opposite side of the rotor from the suction pipe, is reduced with increasing radial distance of such walls from the axis ofthe rotor. The radial distances of the waterpontacting surfaces of the walls increase Vwith increaseof their distance from the suction pipe. v

' It is thus possible to keep the axial velocity constant, not only in the suction pipe, but throughout the body of the water, and this is the condition for the regular continuation of its flow.

The most favorable control of the flow-in 'the body of liquid beyond the rotor is obthe cross-sectional area of the liquid-passage'v between the inner and outer water-contact,- ing surfaces of t-he walls in any plane normal to the axis is the same as the Vcross-sectonal area in'any other plane normal to the axis, orin other words, the cross-sectional areas in radial planes have a constant value.

Preferably the clearance between the walls. of the casing, measured radially, is inversely proportional to their radius, that is, their radial distance from the axis of the rotor..l

tion and forming part thereof-machines ein-- bodying my 4invention are illustrated diagrammatically by way of example.

In the drawings Fig. l is an axial section of a rotary pump,-

' Fig. 2 is an elevation of this pump, partly in section'on the line 2'' 2 in Flg. 1,

Fig. 3 is an axial section of a. hydraullc turbine.

Figs. 4, 5 and 6 are axial sections illustratimparted by any suitable means, such as forv instance an electric motor M. Water is supplled to the rotor b through a suction pipea and a cylindrical extension a of a spiral casing s from which it is discharged through a delivery pipe s', this spiral casing having a rotary machines withouty spiral liquid passage increasing` in radial cross-sectional area in the direction of flow. Referring to Fig. 3, B is the boss-of the rotor, C 1s its shaft, S is the preferably spiral by the water, the passage e l(or E) in the casing which is connected with the suction pipe a(or A) is constituted by walls d and d (or D and D') vwhich are arranged at an angle to the axis f (or F) of the machine and are preferably so curved that the boss b (or B ofthe rotor which is the continuation of the inner wall, is convex.

The most favorable condition for the How in the passage 'e (or E) after leaving the rotor of the pump, or before flowing through the rotor of the turbine, is that the clearance of the passage e (or E) should be regularly decreased as the radial distance of both its walls d', d (or D', D) from the axis f (or F) is increased. Preferably the radial clearance f -o (or R-o) is inversely proportional to the corresponding radius 7' (or R) at that point, and the walls are formed on congruent paraboloids, the vertices 'v' and fv (or V and V) of which are displaced axially.

Inthe simplest case as illustrated in Figs. 1 to '3, the vertex lv (or V) of the inner paraboloid is substantially in the radial plane in which the outer paraboloid intersects the cylindrical extension a (or A of the suction pipe. G). This position of the inner paraboloid with re ard to the line g (or G) is in accordance with the condition of constant axial velocity, for Aat this point the cylindrical suction duct a or (A) becomes -extended into the outer paraboloid wall d (or D) of the'casing so that the area of the duct is is gradually increased and this increase is made up for by a corresponding reduction which is effected at this point by the insertion of the inner paraboloid. A passage e (or formed by two coaxial paraboloid walls is equally suitable for pumps and for turbines. In either case the suction from or the delivery to the suction -pipe is constant as the axial velocity in the ody of liquid is also constant. In machines of the usual type the axial velocity varies quite irregularly within the machine and there is no fixed ratio of the suction pipevelocity and the axial velocity in the other parts of the machine. v

In the'case-of a turbine it is well known that the operation of the suction pipe is very delicate and that it is most important to obin turbines.

This plane contains the line g (or which maintains the axial velocity of the water exactly constant beyond the suction Fig. 3 illustrates by way of example the combination of a passage E-as described with a Water supply passage c in which guide vanes 7c are arranged so that the water is conducted to the casing S radially, as usual These radial guide vanes may be arranged at any suitable distance from the rotor B.

Similarly in a pump a diverging passage e of any desired length may be inserted between the passage e and'the spiral casing.

It may be desirable to increase the diameter of the boss B of the rotor for mechanical or hydraulic considerations. In this case,

as shown in Fig. 4, the area of the suction/ pipe A is restricted by the extended boss B of the rotor. In order to obtain constant axial velocity in this machine, the vertex V" of the inner paraboloid is displaced further into the suction pipe A beyond the line Gr and preferably so far that the'inner paraboloid intersects the radial plane through the junction of the outer paraboloid with the inner `wall of the suction pipe, the position of this plane being indicated by the line G.

If, as shown in Fig. 5, one or more guide vanes z, are provided in the passage E with the objectof changing velocity into pressure or vice versa,- the reduction of the area by these vanes should be considered in adapting the walls D and D to the condition of axial velocity throughout. Therefore the walls D and D are not shaped at these points as exactly congruent paraboloids but, as indicated in dotted lines at h, the clearance between them is increased in proportion to the restriction of the area.

It may be necessary or desirable to consider other factors when determining the configuration of the walls, for instance when the walls are rough. Whatevermay be the configuration of the walls, it should comply with the fundamental. condition that the clearance between the walls must be reduced with their increasing radial distance from the rotor axis.

In the examples shown and described the boss of the rotorhas been shown as being convex toward the suction pipe. The degree of convexity is determined, as is also lthe configura-tion of` the passage e (or E), by the sirable to arrange the vertex of the inner paraboloid not in the line gy (or G) but beyond it, so that the boss projects a certain distance into the suction pipe as shown in Fic. 6.

I wish it to be understood that I do not desire to be limited to the exact details of construction shown and described, for obvious modifications will occur to a person skilled in the art.

I claim: i

Yl. A hydraulic machine comprising a rotor, a casing, and a suction pipe, said casing having on that side of the rotor opposite the suction pipe an annular liquid passage, the water-contacting surfaces of the walls of said liquid passage being formed to coincide with surfaces of paraboloids.

2. A hydraulic machine comprising a ro- Y tor, a casing, and a suction pipe, said casing having on that side of the rotor opposite the suction pipe an annular liquid passa-ge, the water-Contactin surfaces of each ofthe walls of said passageeing formed to coincide respectively with the surfaces of two paraboloids co-axial with the axis of said rotor and displaced axially with regard to each other.

3. A hydraulic machine comprising a rotor, a casing, and a suction pipe, said casing having on that side of the rotoropposite the f suction pipe an annular liquid passage,the

water-"contacting surfaces of `each of thew'alls of said passage being formed to coincide respectively with the surfaces of two parabo-` loids, the suction pipe oining the outer wall in a plane transverse to the axis of the rotor, whic'hfp'lane is intersected by the paraboloid f j'surface of the inner wall.

4. A hydraulic machine comprising a rotor, a casing, and a suction pipe, said casing having on that side of the rotor opposite the suction pipe an annular liquid passage, the water-contacting surfaces of each of the walls of said passage being formed to coincide respectively with the surfaces` of two paraboloids, the suction pipe joining the outer wall in a plane transverse to the axis of the rotor, which plane contains the vertex of the paraboloid surface of the inner wall of said liquid passage.

5. In a hydraulic machine comprising a rotor, a casing, and a suction pipe, said casing having on that side of the rotor opposite the suction pipe an annular liquid passage, the

water-contacting surfaces of each of the walls of said passage being formed to coincide with the surfaces of two paraboloids which are coaxial with the axis of said rotor and displaced axially with regard to each other, said suction pipe being joined to the outer wall ina plane s transverse to the axis of the rotor, said plane containing the vertex of the innerparaboloid which coincides with the surface of the inner wall of said liquid passage. y

6. A hydraulic machine comprising a suction pipe, a casing having an inner cylindrical wall portion joining said suction pipe, a rotor having vanes whose outer ends lie on the surface of an imaginary cylinder, said ends rotating in close proximity to the said inner cylindrical wall portion of the casing, said casing having on that side of the rotor opposite the suction pipe an annular liquid passage whose mean'ra-dius increases with increase of its distance from a plane through the rotor, the clearance lbetween the walls of said annular liquid passage decreasing with said increase of radius, said annular liquid passage being arranged to conduct liquid as a liquid annular body free to rotate about one axis of the annular body while permitting the liquid to travel bodily in the general direction of said axis of rotation.

In testimony whereof I aiix my signature.

FRANZ LAWACZECK.

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