US2969665A

US2969665A - Fabric washing machine

Info

Publication number: US2969665A
Application number: US541746A
Authority: US
Inventors: Saverio Francois Victor Desire
Original assignee: Philco Ford Corp
Current assignee: Space Systems Loral LLC
Priority date: 1955-10-20
Filing date: 1955-10-20
Publication date: 1961-01-31
Anticipated expiration: 1978-01-31

Description

Jan. 31, 1961 F. v. M. D. SAVERIO 2,969,665

FABRIC WASHING MACHINE Filed Oct. 20, 1955 5 Sheets-Sheet 2 INVENTOR.

FRANQOIS VICTOR MARIE DSIRE SAVERIO.

ATTORNEY.

Jan. 31, 1961 Filed 001.. 20, 1955 F. v. M. D. SAVERIO 2,969,665 FABRIC WASHING MACHINE 5 Sheets-Sheet 3 1 1 I I 6 M M I INVENTOR FRANpoIs VICTOR MARIE os'slR SAVERIO.

ATTORNEY.

Jan. 31, 1961 F. v. M. D. SAVERIO FABRIC WASHING MACHINE 5 Sheets-Sheet 4 Filed Oct. 20, 1955 vmw INVENTOR. FRANQOIS VICTOR MARIE DSlR' SAVERIO.

BY W

ATTORNEY.

1961 F. v-. M. D. SAVERIO 2,969,665

FABRIC WASHING MACHINE Filed Oct. 20, 1955 5 Sheets-Sheet s INVENTOR.

FRANQFOIS VICTOR MARIE osm SAVERIO.

TTORNEY.

United States Patent FABRIC WASHING MACHINE Francois Victor Marie Desire Saverio, Paris, France, as signor, by mesne assignments, to Philco Corporation, Philadelphia, Pa., a corporation of Pennsylvania Filed Oct. 20, 1955, Ser. No. 541,746

3 Claims. (Cl. 68-184) or less efliciently by imparting whirling movements to the liquid.

In practice the arrangement is such that the liquid is projected from the bottom toward the top of the tub along paths which are curved in each diametral plane and run along the sides of the tub, curve toward the centre thereof and then descend substantially axially, these movements being combined with the rotation of the mass of liquid about the axis of thecentrifugal pump. The liquid flowing downwardly along the axis must return to the inlet or suction side of the pump. The most obvious way to obtain this is tocover the rotoror impeller of the pump with a fixed stator or diffuser comprising a central aperture for the suction of the liquid flowing downwardly along the axis of the tub. However, this solution is impracticable because the fabric or clothes carried along by the circulation of the liquid would close up the suction aperture of the pump and would render operation uncertain.

Thus, in practice, constructors of washing machines have avoided this solution and have adopted arrangements comprising a pump or impeller which is not covered by a stator, that is, a disc provided with ribs on its upper face which is necessarily of very low efficiency. But the major drawback of these arrangements is that the fabric carried along by the liquid enters into contact with the rotating disc and the rubbing of the fabric on the ribs rotating at high speed results in rapid wear of this fabric.

The washing machine embodying the invention is of a type in which the rotor or impeller of the pump which circulates the liquid is covered by a stator or diffuser so as to obtain a veritable centrifugal pump of high efficiency, this diffuser comprising two series of jet nozzles along its periphery, some of these nozzles being so oriented as to cause the liquid to travel in a substantially elliptic path, the liquid rising up the walls and thereafter descending axially, and the other nozzles being so oriented as to project a part of the liquid upwardly along the axis or obliquely in the direction of the axis of the tub, whereby the fabric situated in the central part of the tub is thrown laterally toward the periphery and reenters the circuit of the liquid, the latter returning to the central suction aperture of the pump through perforations provided in the tub and by way of the bottom of a vessel in which the tub is disposed.

Further, the walls of the tub preferably comprise inwardly directed ribs or projections which contribute to separate the liquid jetsfrom the wall and cause them; to curve toward the axis.

Experiments carried out for the purpose of obtaining Patented Jan. 31, 1961 ice a washing action of maximum efficiency-in which the behaviour of the fabric in the course of washing was investigated-have furnished a number of conditions to be satisfied by the various elements of the machine if this maximum efficiency is to be obtained.

The object of the invention is to provide a washing machine of the above-indicated type in which these conditions are satisfied.

After draining the tub, the rinsing or washing liquid is more completely eliminated by a damp-drying or spindrying operation. Thus the perforated tub is advantageously rotatably mounted relative to the vessel, it being held stationary when washing or rinsing but rendered rigid with the shaft oft he pump by a clutch when spindrying.

. Further features and advantages of the invention will be apparent from the ensuing description with reference to the accompanying drawings, in which:

Fig. 1 is a vertical sectional view of a washing machine embodying the invention;

Fig. 2 is a sectional view of the clutch, taken along line 2-2 of Fig. 1;

Fig. 3 is a plan view of the machine on a reduced scale; 1

Fig. 4 is a sectional view of the circulation pump, taken along line 4-4 of Fig. 3.

Fig. 5 is a sectional view of the circulation pump, taken along line 55 of Fig. 3;

Fig. 6 is a diagrammatic axial sectional view of the machine showing the mode of operation;

'Fig. 7 is a corresponding plan view of the machine;

Figs. 8 and 9 are diagrammatic views of the tub which are taken at to one another and show the action'of the oblique jets; a

Fig. 10 "is a similar view showing the action of the tangential jets;

Fig. 11 is a plan view showing the co-operation of the oblique and tangential jets;

' Fig. 12 is a perspective view corresponding to Fig. 11; Figs. 13 to 15 show various orientations of oblique jets which do not give the desired result;

Figs. 16 to 18 are diagrams showing projections of the obrllique jets on three planes perpendicular to one anot er;

Fig. 19 is a diagram showing the influence of variations in the inclination of the oblique jet's on the diambottom of a cylindrical washing tub 4 having a vertical axis. The diffuser comprises a lower suction or inlet aperture 5 and a peripheral chamber 6 having two series of jet nozzles or apertures.

The

nozzles

7, 7 of one of the series, two nozzles being provided in the presently described embodiment, are in diametrally opposed relation and are so disposed as to dire'ct'the liquid in a substantially tangential direc tion (Fig. 7). The

nozzles

8, 8 of the other series, two being provided in the presently described embodiment, are disposed at 90 to the

nozzles

7, 7 and are so arranged as to direct the liquid upwardly and obliquely toward the axis (Fig. 6).

The bottom of the tub 4 is connected to the cylindrical part thereof by a portion 9 which is conical, spherical or parabolic in shape. Thus the liquid jets issuing from the

nozzles

7, 7 curve upwardly, run up the cylindrical wall and return axially downwardly along paths which are roughly elliptic. This movement is combined with the rotation of the mass of liquid due to the tangential ejection 'soithat'the liquid jets ofstrearr'rsare also'wound "round ahelical' pathabouttheaxis' of the tub.

Th'e'tub 4 is'provided withperforationsld'over a part "of its "cylindrical wall and with "pressed portions which form projections or ribs'il extending 'along' vertical. generat'rices, four projections being provided in the presently "12 adapted to contain the washing liquid. This vessel rests'bybracketslls on'angle-irons 14 attached'to the inner wall of a casing 15. This vessel 12 comprises in its base alarge opening 16 throughwhi'ch extends abear- 'i'ng'unit 17. The shaft18 oftheflcentr'ifu'gal pump impeller 1, is rotatably mounted centrally of a tubular shaft 19 byrrieans of a sealingbushing 20. These

coaxial shafts

18 and 19 are disposed in the bearing unit 17, the

latter enclosingsuitable sealing members 20*, 20 and thrust bearings 20 and 21. The bottom of the vessel is connected'in a fluid-tight manner to' the bearing unit 17 by a rubber seal 22. The tub is secured to the tubular shaft'19 by radial arms 11 Keyed to the lower end of theshaft'18 of the pump is a'pulle'y'23 around which is passed a belt 24 which is also passed around pulley 25 "disposed at the end of "the output shaft 26 of anelectric "motor 27 rigidly mounted on afpl'ate 2S Whichismo'unted, through the medium of three rubber shock-absorbing blocks 29, on the lower fixed stand 30 of the casing 15.

Mounted'on the other end of the shaft 26 is a centrifugal draining pump 31 the inlet orsuctionaperture of which is connectedby a'flex'ible'hose 32 'tothe outlet aperture 33 of a filter 34which eommunicates"with the interior of the vessel12. The discharge pipe .35 of this pump is connected to a flexible'ho'se 36" terminating in a hook-shaped pipe fitting (not shown'in the drawing) so that the vessel 12 maybe drained into a basin, sink or the like.

The washing machine may be closed'bya lid 37 and the casing 15 is provided withan inspection door 38 facing the filter.

The shaft 18 rigid with the-"centrifugal pump impeller and the hollow shaft 19 of the tub may be interconnected 'to 'rotate together by a 'disc clutch 39, the moving elernents of which are controlled by a bell-crank 40 which terminates at one endin a fork 41 controlling the clutch and at the other end in a'locking nose 42 which is capable of engaging teeth or projections formed on the periphery of a cup 43 rigid with the hollow shaft 19. The clutch 39 is housed in a fluid-tight housing and operates in an oil bath 39 Connected to the end of the pivot pin'44 rigid with the bell-crank 40 is a flexible control device of the conventional Bowden type. A valve 45 is disposed in the discharge pipe of the pump 31 and is controlled by a similar flexible control. These flexible controls are connected at their other ends to identical control buttons 46 and 47 respectively (Fig. 3).

The hand control by means of buttonsmay be replaced by,or combined with, electromagnetic controls disposed in a housing.

There may'be' disposed in the bottom of the vessel 12 a conventional screened electric heating resistance 60, or, below'the bottom of the vessel, a gas burner, if' the machine is not supplied with hot Water.

The washing machine operates in the following manner:

After the dirty clothes or fabric have been placed in the tub and the vesselhas been filled with cold rinsing the valve 45 having been previously closed and the clutch 39 released. The locking nose 42 prevents the shaft 19 and the tub 4 from rotating. The centrifugal circulation pump impeller sucks the liquid from the bottom of the vessel and expels it through the two series of nozzles in the manner explained above. The mass of fabric A (Fig. 6) is carried along by the current of liquid repre sented by arrow F. Furthen'the liquidjets, represented by arrows F, act on the fabric pieces situated in he centre of the tub and cause these pieces to return to current F. The liquid which arrives'at the centre of the tub must necessarily return to the inlet 5 so as to be once more sucked in by the pump. This is obtained by a centrifugal movement of the liquid through above all the relatively calm zones disposed between the

nozzles

7, 7, 8, 8 and even through the perforations 10 in the tub 4. The pieces of fabric are entrained by this centrifugal flow-of the liquid, are subjected to the whirling action of the'latter, and then return to the centre, this cycle being continuously repeated while the pieces rotate in the tub. This'movement exerts an energetic cleansing action without the fabric ever having a tendency to rub against and be worn by the metal parts or the impeller 1, the fabric being screened from the impeller by the diifuser 3 and being thrown away from the latter by the jets F. 7

When the soaking or washing is terminated, the bot- 'tom' 47 is operated so as to open the valve 45, and the draining pump 31,"which had heretofore operated in a closed circuit, drains off the liquid through the filter 34 (access may be had to this filter through the inspection door 38 and the removable plug 61).

When the liquid has been evacuated, the

shafts

18 and 19 are rendered rigid with one another, by acting on the button 46 which engages the clutch 39, and the tub is driven with the impeller 1 athigh velocity and the fabric contained in this tub is spin-dried.

In all'these operations the rub, the

shafts

13, 19, the bearing-unit"17,the'plate 28, the 'rnotor 2'7, and the "pump 31-constitute "an assemblage which I is free to undergo alimitedmovementof precession relative to i the vessel 12; the casing 15, and the stand fiti, on account of the provision of the rubber blocks 29 and the rubber joint 22, without any risk of dangerous vibrations or breakages. This movement of precession ceases as soon as the critical velocity of the assemblage is attained, which is around r.p.m.

In'the machine described above it has" been seen that the pieces ofjfabricentrained by the 'liquidi'currents rep- 'resented'by! the arrows F (Fig. 6), have a tendency to accumulate'at A but that this mass of fabric is dispersed and the individualpieces of fabric areunrolled by the currents represented by the arrows F. It is the choice of the paths F and F of these liquid currents which influences the rate and intensity of the washing, and according'to the invention thev followingprinciples have been arrived at:

It is essential to create an intenserelative movement betweenthe waterand the fabric and to avoid not only the stagnation but also the continuous rotation of a com- ;pactmassof fabric, such as that shown at A, whether this mass accumulates on the axis of the tub or is distributed annularly. .Hence, the individual pieces of fab ric :must be continuously renewed'in front of the liquid jets and mustnot agglomerate in a stationary manner a in a compact mass. v

The tangential liquid jets 'issuingfrom the nozzles '7 -(Fig. 7), which curve in the form of an ellipse (Fig. 6)

while being bent in the form of a-h'elix, fulfill a double function:

(a) They ensure the rotation and the return to the circuit of the piecesof fabric originating from the dispersion of the mass A;

"(b)Th'eycause' thepieces'of'fabric tobe'presented 5 just above the oblique jets represented by the arrows F (Fig. 6).

In this operation, the ribs 11 play an important part since they deflect the liquid current toward the centre by separating it from the wall of the tub, and this liquid current drives the fabric into the active zone of the oblique currents F. Thus a close relationship exists between the shape, the orientation, and the relative disposition of each nozzle 7, of the nozzle 8 which leads the nozzle 7 in the direction of the arrow (Fig. 7) and of the adjacent rib or projection 11. The shape of the bottom of the tub and of the intermediate portion 9 also affect the washing action.

Further, the jets F must have such orientation that they break up the mass of fabric A in an appropriate zone of the tub, this dispersion of the individual pieces of fabric being as complete as possible.

As mentioned above, an object of the invention is-tospecify the required dispositions for optimum conditions of operation.

These dispositions will now be specified and explained.

'In Fig. 8, 4 designates the tub the bottom of which is connected to the cylindrical wall by a wall 9 of conical, parabolic or spherical shape. It can be seen that the axes of the jets F, F are contained in two planes perpendicular to the plane of the, figure, and intersect on the line through the nozzles 8-8 These planes make an angle 7 with the vertical plane, w

As is shown in Fig. 9, the axes F, F of the jets are not perpendicular to the lines 88 :of intersection of the two planes, but they make with the perpendicular h an angle the projection of which on the plane of Fig. 9 is 8-, .7

The two straight lines F may be considered as recti linear generatrices of a hyperboloid of revolution. H generated by rotating one of these straight lines about the axis X--X. This hyperboloid has a plane of symmetry the trace of which in Fig. 9 is the straight ;line Y Y; this plane contains the perpendicular ab common to the generatrices F,F.

The jets do not rotate and therefore the hy'perboloid H is not generated by the rotation of the lines F, F. However, these jets deviate from their rectilinear path on account of the rotation of the liquid caused by the tangential jets F, F. Each point on these straight lines has a tendency to describe a more or less distorted circle about the axis X-X so that it might be assumed as a first approximation that the hyperboloid is in actual practice substantially obtained. In any case reference *to this hyperboloid H will facilitate understanding the invention.

If desired, the diffuser of the pump may be rotated,

for example at relatively low speed, although this arrangement does not appearto be necessary and to a certain extent complicates the mechanism.

As shown in Fig. 10, the jets F, emitted tangentially'by the nozzles 77 riseup the walls 9 and 4 and turn inwardly in the ventical plane along an elliptic arc; in the horizontal plane they have a tendency'to describe a circle along the wall 4 of the tub. However, the ribs 11 deflect their path toward ,the centre. The velocity at which the jets F, F leave the nozzles 7 7 the shape of the bottom 9, the diameter of the tub 4, and the extent to which the ribs 11 protrude, determine ;this' path. Under the elfect of these jets deflected by the ribs, the pieces of fabric have a tendency to rotate and pass by the restricted zone of the hyperboloid. This zone will be termed hereunder striction zone. l H

The synthesis of these various currents is shown Fig. 12. It is clear from the latter how the pieces of fabric, which are driven along a helicalpath by the tangential jets F and are then deflected toward the centre due to the action of the ribs 11', tend to'pa'ss into the striction zone of the hyperboloid H situated in the plane of the perpendicular 'qb. common to the jets F',F'.

It can also be seen how the jets F, F, in impinging the mass of fabric, break it up and drive the pieces of fabric upwardly toward the periphery of the tub, where they tend to fall and encounter once again the jets F.

Experiments show that this energetic churning does in fact occur in this manner, this being easily verified in observing the evolutions of a piece of coloured fabric added to pieces of white fabric. The coloured fabric arrives in the mass of fabric situated in the striction zone, emerges and separates itself therefrom, moves once more toward the periphery, disappears, and then reappears in the striction zone, this cycle being continuously repeated. At the same time, the piece of fabric contracts and expands and changes shape continuously. This behaviour of the fabric denotes intense and uninterrupted relative movements between the pieces of fabric and between the latter and the liquid which is particularly advantageous to an efficient washing action without appreciable rubbing against the metal elements, resulting in minimum wear.

In order to obtain such conditions of operation, the arrangement must be such that the striction zone is situated at a suitable level and has an optimum diameter, and that the jets F bring the fabric into this striction zone with suitable direction and intensity.

Given the shape of the tub, i.e. the ratio between its diameter and height, whichshould not differ greatly from unity, the power of the jets F and the damping effect obtained by the rubbing and whirling of the current of liquid they produce, the jet F issuing from the nozzle 7, for example, must reach the striction zone after having travelled helically round slightly more than a quarter of the circumference of the tub so as to encounter the jet F issuing from the nozzle 8 immediately adjacent the nozzle 7. During this movement the jet F must rise helically, under the effect of the inclination of the wall 9, such distance as to reach the level of the striction zone. The extent to which the ribs 11 protrude inwardly must be suflicient to curve the jet Fin such manner that it effectively encounters the jet F (this is obviously approximate, since the jets are not parallel but diverge as they leave the nozzles). Furthermore, the power of the jets F and the angles [3 and a (Figs. 8 and 9) must be such that the striction zone of the hyperboloid has a suitable diameter and is situated at the desired height above the bottom. If the diameter is too great, the zone of concentration of the fabric is excessive and'there is some risk that certain parts of this zone may be unaffected by the jets F which would result in a part of the fabric failing to be subjected to an efficient washing. If the diameter is too small, the jets F become convergent, the hyperboloid tending toward a cone. In this case a ring of fabric tends to rotate indefinitely about the reduced striction zone, only the pieces of fabric which come into the vicinity of the vertical axis of thetub being expelled by the jets F. i If the striction zone is too high it becomes practically impossible sufliciently to increase the pitchof the helix, corresponding to the path of the jets F, so that the latter can bring the fabric into this striction zone. Moreover, the jets F no longer have a sufficient residual momentum for breaking up the mass of fabric concentrated in the striction zone. If the striction zones is too low, a large part of the mass of liquid contained in the tub above this zone no longer takes an active part in the desired movements and the frequency of the periodic action to which the pieces of fabric are submitted becomes too low for an efficient washing.

Experience has confirmed the theory that this striction zone of the hyperboloid H must be situated in the vicinity of the plane situated mid-way up the immersed part of the tub" and that the diameter of this striction zone must be definitely smaller than the distance between 8 and 8? without, however, being as small as a small fraction of the latter. Now, the height and the diameter of the stric:

'tion zone are determined by the

angles

3 and 7 mentioned above. When the angle 5 is zero, the jets F are contained in two parallel planes (Fig. 13.) and there is no longer any striction zone. If the angle v is too small the striction zone is too high and vice versa (Fig. 14). Decreasing the angle 5 below its optimum value excessively dilates and tends to lower the striction zone, whereas increasing this angle has the opposite effect. Hence, it is necessary to ascertain the required relationship between, the various elements of the problem and the factors which determine the position and diameter of the striction zone.

Firstly, in most machines having a rotor or pump disposed in the bottom of the tub for the purpose of obtaining a suitable relative movement of the fabric and water, the volumeof water in the washing tub must bear a certainrelationto the weight of the fabric to be washed.

Experience has shown that the appropriate proportion is around 15 litres 2 litres) of water per kilogram of fabric to be washed. The machine embodying the invention is intended for household use, i.e. the capacity of the machine corresponds to between 3 and 5 kg, or at the most 6 kg. of fabric or clothes. For a greater amount of'fabric the diameter of the tub would be such that in view of the volume of water necessary and the velocity of rotation required for the spin-drying, the tangential velocities would be excessive for this kind of machine owing to the vibrations set up through lack of balance. Indeed, in washing machines in current use the peripheral velocities used for spin-drying are around 8-9 metres per second. It is here proposed to improve the spin-drying by increasing the linear velocity of the tub in respect of spin-drying to about 12 metres per second.

In view of the fact that during the spin-dryingoperation the tub rotates at the same velocity as the impeller of the pump, since they are rendered integral by the clutch, and that the rotational velocity of the impeller must be around 500-600 r.p.m. in order to obtain effective jets of liquid, and given the mean diameter of the impeller, the diameter of the tub must be comprised between relatively narrow limits.

Further, the ratio between the height of the immersed part of the tub and the diameter of the latter must not be too different from unity for reasons of ease of charging, efliciency and amplitude of the movements of the fabric, and size of the machine.

The following relations are therefore arrived at:

In order to treat P kg. of clothes or fabric it is necessary that the washing tub contains eP litres of water (e varying between 13 and 17). This volume of water is expressed, as a function of the diameter D and the height H of the immersed part of the tub, by the relation:

The ratio K=H/D, as has been seen above, must not differ too much from unity and empirically one might choose a ratio comprised between 0.65 and 1.0.

Substituting KD for H in Formula 1 there is obtained 42 D- P) decimetres the coefilcient varies from namely from 2.60 to 3.35.

The diameter of the tub must therefore be comprised between 2.6P- and 3.55P

Thus, for a machine intended to wash 3 kg. of fabric or clothes, D should be comprised between 3.68 and 483 mm.,

8 and fine machine intended to wash 6 kg. of fabric between 473 and585 mm.

However, the necessity of having a rotational velocity of 500-600 r.p.m. (8.35-10 r.p.s.) and the choice of a tangential velocity of 12 metres per second, limits the choice of the possible diameters between 380 and 460 mm., so that a charge of 3 kg. of fabric is the maximum capacity of a machine of this design.

The diameter 2R of the diffuser of the pump must be as large as possible. Owing to the general inclination and the length of the generatrix of the connecting surface 0, which is required for curving the jets F in the form of a helix of suitable pitch, this diameter 2R must not exceed in practice half the diameter D of the tub, namely R=D/4. R must be comprised therefore between 95 and 115 mm. and it is related to the charge of fabric by the following expression, in which K varies from 2.6/4 to 3.35/4:

R- KP (R being expressed in decimetres).

This striction zone of the hyperboloid must be situated half way up the tub, namely a distance d from the bottom, so that d= to 9:1.315: to 2R Its diameter 2r must be definitely smaller than 2R (namely 0.8 maximum) without being too small (the minimum ratio being around 0.6), whence Knowing this, it is easy to calculate the angles ,8 and 7 which satisfy these conditions.

Figs. 16 to 18 are diagrams corresponding to the inclination of the jets F which are projected on three perpendicular planes, the plane of Fig. 16 being the vertical plane containing the

nozzles

3, 8 Fig. 17 the vertical plane perpendicular to the line through the

nozzles

8, 8 and Fig. 18 the horizontal plane.

By tipping the plane containing 8 b to coincide with the vertical plane of Fig. 17 by rotating it through the angle 7, it is easy to construct the straight line F (Fig. 16) which makes the angle a with the vertical, this angle having in the plane of Fig. 16 the projection of angle )9. Knowing that 0a=ob=r (radius of the striction zone in correct proportion in Fig. 18) and that 0c=d (height of the striction zone in correct proportion in Figs-16 and 17) and that 0 8:0 8 =R, it is easy to calculate the values of r and d as a function of R.

Hence It may be calculated that and tan a=tan 5 cos 'y The variations in d and r are shown in Fig. 19, where the ordinates represent d/R and r/R and the abscissae tan a. Families of curves d and r are obtained for difierent values of 'y (14", 16, 19 and 30).

It is clear from these curves that r/R decreases when u increases and when 7 decreases, whereas d/R first increases with a up to a maximum, then decreases, the maximum increasing when 7 decreases, thus forming a very accentuated point for low values of 'y. The maximum or d/R, which is found easily by eliminating the derivative of the function R c s 7 tan a: Sin 7 +138Jl -01:

9 corresponds to such values of a and 7 that sin 'y=tan a and The above-indicated conditions that r should be comprised between O.5R and 0.8R', together with the condition that d should be comprised between 1.3R and 2R, permits calculating that a should be comprised between 11 and 25 and 7 between 14 and 19. The corresponding parts of the diagram have been cross-hatched. Corresponding to the values of a are the almost identical limits for ,3 (11 to 26). 7

As the jets F are not geometric lines but streams of liquid which are more or less-divergent, the following limits may be adopted in practice:

a comprised between 10 and 30 comprised between '13 and 20 Figs. 20 to 22 show .how these angles are incorporated in the construction of the diffuser 3 and the

nozzles

8, 8 In Fig. 22 the angle 7 that the jets must make with the vertical has beenindicated (13 to 30). In order to obtain this, the outlet face nm of the nozzle must be tangent at n to a straight line np which makes with the vertical a corrected angle 7', in order to take into account the fact that the axis of the jet F' is not strictly parallel to np. This correction can only be made by trial and error.

Similarly, it can be seen from Fig. 21 that the angle ,6 that the tangent at t to the face st at the nozzle 8 makes with the vertical must be determined by trial and error, in order that the jet F makes an angle with the vertical (comprised between and 30).

The following example shows the conditions adopted in accordance with the invention for a household washing machine intended to wash 3 kg. of fabric or clothes.

The foregoing considerations determine the shape of the hyperboloid H (Figs. 8 and 9) in relation to the tub.

There remains to be determined the form of the inclination of the connecting surface 9 and the projection of the ribs 11 curving the jets F in the vertical plane (Fig. 10) and in the horizontal plane (Fig. 11) so that they urge the fabric into the striction zone of the hyperboloid vertically above the jets F. Calculation is of little use in this respect, the desired result being best obtained by trial and error. This procedure is, however, considerably simplified since the level and the diameter of the striction zone may be estimated with very reasonable accuracy. It is extremely easy in a prototype cylindrical tub to dispose on the bottom of the latter a removable ring, such as that shown at 70 in Fig. 10, and to form the ribs 11 of removable, shaped rods. Hence, with a set of rings whose upper faces differ in shape and a set of rods having different sections and thicknesses, it will be easy to select those which result in the desired paths for the jets F. For this purpose, the latter may be more .10 clearly indicated by means of coloured ribbons'fixed to the outlets of the nozzles.

It will be noticed that this rugged washing machine is economical and comprises no bears or expensive mechanical parts.

Although an embodiment of the invention has been described, many modifications and changes may be made therein without departing from the scope of the appended claims.

Having now described my invention what I claim as new and desire to secure by Letters Patent is:

1. In a clothes washing machine of the type in which wash water is drawn into a pump casing and discharged therefrom into a tub having a bottom wall and an upwardly directed cylindrical side wall, said tub having a central vertical axis and adapted to contain the wash water and clothes to be washed, said casing being mounted in said tub and disposed centrally and adjacent said bottom wall, the combination comprising: a plurality of jet nozzles each leading from said casing and opening into said tub, certain nozzles opening upwardly and generally in the direction .of the central vertical axis of said tube to emit a first series of jet streams in flow paths angled upwardly and toward said axis from different sides thereof whereby said first series of jet streams impinge upon the clothes to suspend them in the wash water and above said bottom wall, certain other nozzles opening laterally and in directions substantially tangential to said casing and away from said axis to emit a second series of jet streams in flow paths directed laterally toward and following said side wall; and deflector elements carried by said side wall, said elements extending vertically over the greater part of the height of said side wall and projecting therefrom toward said axis to deflect said second series of jet streams away from said side wall and toward said axis whereby they impinge upon the clothes to maintain them off said side wall.

2. In a clothes washing machine of the type in which wash water is drawn into a pump casing and discharged therefrom into a tub having a bottom wall and an upwardly directed cylindrical side wall, said tub having a central vertical axis and adapted to contain the wash water and the clothes to be washed, said casing being mounted in said tub and disposed centrally and adjacent said bottom wall, the combination comprising: a plurality of jet nozzles each leading from said casing and opening into said tub, alternate nozzles opening upwardly and generally in the direction of the central vertical axis of said tub to emit a first series of jet streams in flow paths angled upwardly and toward said axis from diiferent sides thereof whereby said first series of jet streams impinge upon the clothes to suspend them in the wash water and above said bottom wall, the remaining nozzles opening laterally and in directions substantially tangential to said casing and away from said axis to emit a second series of jet streams in flow paths directed laterally toward and following said side wall; and deflector elements carried by said side Wall, said elements extending vertically over the greater part of the height of said side wall and projecting inwardly therefrom and toward said axis to deflect said second series of jet streams away from said side wall and toward said axis where they impinge upon the clothes to maintain them 011? said side wall.

3. In a clothes washing machine of the type in which wash water is drawn into a pump casing and discharged therefrom into a tub having a bottom wall and an upwardly directed cylindrical side wall, said tub having a central vertical axis and adapted to contain the wash water and clothes to be washed, said casing being mounted in said tub and having a circular peripheral wall extending upwardly from said bottom wall and spaced inwardly from said side wall, the combination comprising: a first pair of jet nozzles each leading from said casing 11 and havingtan .outlet .portion, a second pair of .jet nozzles each also leading from said casing and having an outlet portion, the: outlet portions of: the nozzles of said first pair being locatedat diametrically opposite portions of said peripheral wall of the casing and opening upwardly and.v generally in the direction oflthe central vertical axis of. the tub. to emit a first seriesof jet streams inflow paths angled upwardly and toward said axis from diametrically opposite sides thereof wherebysaid first series of jet streams impinge upon the clothes to suspend them in the wash water and above said bottom wall of the tub, the outlet portions of :the nozzles of said second pair beingvlocated at other diametrically'opposite portions of said peripheral wall of the casing and opening laterally and in directions substantially tangential to said peripheral wall and away from said axis to emit a second series of jet streams in flow paths directed laterally toward and following said sidewall of the tub; and means for deflecting said second'series of jet streams from said side wall toward said axis whereby-they impinge upon the clothes to maintain them ofl said side wall, said means consisting of ribs mounted equidistantly on said side wall, said ribs extending vertically over the greater part 12 of the height of said side wall and projecting inwardly therefrom toward said axis.

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