USRE20444E - Impregnation op articles by centrifugal means - Google Patents

Description

July 13, 1937. w. A. HYDE IMPREGNATION OF ARTICLES BY CENTRiFUGAL MEANS Original Filed May 29. 1931 2 Sheets-Sheet 1 zZ/mn [1297 July 13, 1937. w, A, HYD Re; 20,444

IMPREGNATION OF ARTICLES BY CENTRIFUGAL MEANS Original Filed May 29. 1951 2 Sheets-Shet 2 .fi/m @227 A Jfd Reissued July 13, 19 37 IMPEEGNATION or earnin s BY CENTRIFUGAL MEANS William A. Hyde, Worcester, Masai, assignor to Leon J. Barrett, Worcester,

Original No. 1,981,453, dated November 20,1934, Serial No. 540,960, May 29, 1931. Application for reissueDecember 9, 1935, Serial No. 53,679

e Claims. (or. 21-24) The present invention relates to an improved method and means for impregnating articles of various kinds through the action of centrifugal force on a rotating body of liquid in which the articles to be impregnated are submerged.

The practice of the method contemplated by the present invention is characterized by the development of hydrostatic pressure in a rotatmg body of liquid surrounding the articles through the action of centrifugal force. As a result of the pressure acting radially with respect to the axis of rotation of thebody of liquid, the liquid is forced through the article's, thereby expelling air from the interior of the articles, and resulting in more complete impregnation than has been heretofore obtained by any other means. The invention also contemplates the building up of a pulsating pressure in the liquid due to reactions developed in the rotating container for the bodyof liquid, whereby more efl'ective impregnation is obtained, and the above and other advantageous features will more fully appear from the following description with reference to the accompanying drawings, in which:- Fig. 1 is a side elevational view, partially diagrammatic, illustrating the apparatus for carrying out the invention. Fig. 2 is a horizontal sectional view along the line 22 of Fig. 1, looking in the direction of the arrows.

Figs. 3 and 4 are fragmentary views, partially,

tratlve embodiment of apparatus for carrying out the invention, although as will hereinafter appear, other types of similar apparatus may be employed without departing from the prin- 45 ciple underlying the invention. 'i'he apparatus consists of, a .base I supporting a hollow cylindrical casing 2, the bottom-of which provides a central opening 3 surrounded by an upwardly extending flange 4. Liquid collecting'at thebottom of the casing 2 will be retained by the flange 4, and may be withdrawn from the casing 2 through a passage 5 leading to a storage tank 6, the purpose of which will hereinafter ap-*'" 5 pear. I

A hollow bowl I is rotatably supported within the surrounding casing 2 by a shaft 8 extending through the opening 3 and spaced from the flange 4, the shaft 8 being adapted to be driven by means of a motor 9. Preferably the bowl I and its driv-' ing motor 9 constitute a unit, the entire weight 6 of whichis supported bya ball and socket bearing III provided by the base I, the shaft 8 being rotatable in bearings carried by the motor frame members II, which in turn transmit the weight r of the whole unit to the ball and socket bear- 10 ing Ill. Consequently, the entire unit, including the rotatable bowl I anddriving motor 9, is adapted to swing about the bearing III in the manner of an inverted pendulum. In order to support the bowl and motor unit in a substan- 1 tially vertical position, the lower motor frame member II provides a number of lugs l2, I! each providing an opening for loosely receiving a stud I3 projecting upwardly from the base I. That portion of each stud l3 extending above the lug 20 I2 is surrounded by a spring I! and nuts l5 serve to hold the springs H on the studs IS in engagement with the lugs l2. As indicated in dotted. lines in Fig. 2, the motor frame member ll provides four lugs l2 arranged dlametri- 25 cally and theseveral springs ll pressing downwardly on the lugs I! serve to maintain the entire bowl and motor structure in an upright position on the bearing IIL While the combined pressure of the springs ll tends to maintain the so axis of the bowl unit vertical, it is-evident that owing to the compressibility of the springs l4 it is possible for the bowl I to have a swaying. movement about the bearing III as a center in response to unbalanced forces set up during rotatlon of the bowl at high speeds. This swaying of the bowl is necessarily uniform, or periodic. in character, owing to the symmetrical arrangement of the springs ll about the axis of the bearing II, the tension of thesprings I! as determined by the nuts II serving to control, or limit, the'amplitude of such periodic swaying, movements, for a purpose which will hereinafter The bowl 1 provides a cover I having a central opening I! to which'fluid is adapted to be supplied from a pipe I. having a control valve l8. Fluid is supplied to the pipe I! from any suitable source, and a convenient way of keeping the pipe continuously supplied with impregnating fluid without appreciable loss in the system is illustrated more or less diagrammatically in Fig. 1. In this arrangement, atank 20 mounted above the bowl I is adapted to supply fluid by 55 gravity to t e pipe ",arid the tank 2| is'adapted to be kept at least partially filled by means of v a pump 2| located in the lower tank 6 and adapt that a circulation of liquid is maintained under the control of the valve I9 in the supply pipe I8.

In carrying out the invention with the above described apparatus, the cover It of the bowl 1 is removed and an annular cage 23 containing the articles 24 to be impregnated is positioned within the bowl I and the cover It replaced. The outside diameter of the cage 23 is substantially equal to theinside diameter of the bowl I, so that the cage is substantially coaxial with the bowl.

' The cage 23 is preferably composed of open work material such as wire mesh, so that the walls of the cage offer substantially no resistance to the passage of liquid therethrough. The inside diameter of-the cage 23 is considerably greater than and stop with the bowl.

the diameter of the opening II in the cover I6 and anumber of radial'blades 25 are provided by the bowl I within the surrounding cage 23, the purpose of which is to cause the liquid to start in the middle of the bowl determined by the diameter of the opening II in the cover I5, around the edges of which excess fluid escapes into the casing 2 as the pressure builds up within the bowl..

Considering now the articles 24 within the open work cage 23, it is evident that they will be subjected to a hydrostatic pressure which is at its maximum at'the solid wall ofthe bowl I, the pressure decreasing inwardly towards the axis of rotation. With a given speed for a bowl of given radius, it has been found that a pressure as high as 60 pounds per square inch will be developed at the wall of the bowl I, while a reduced presa that as rotation continues, the liquid is forced.

completely through the articles 24, at a rate depending upon the speed of rotation, the radius of the cage, the density or fluidity of the liquid and the permeability of the articles. As the impregnation of the articlesprogresses, any tendency for light articles to move inwardly towards the rotational axis is resisted by the confining cage 23, although obviously any air therein will be expelled toward the center of the bowl, such expelled air finally escaping into the central space below the cover opening I'I. As previously pointed out, the entire rotating unit, including the bowl I and its driving motor, is capable of swaying about a vertical axis'passing through the bearing III, and it has'been found that the amplitude of this swaying movement can be controlled to cause the articles in the bowl to be subjected to pulsating pressure. As setforthg' above, the hydro-static pressure developed withinrim of the bowl .I.

the bowl I when the latter is rotating at a given speed, is dependent upon the radial distance of any point under consideration from the axis of the bowl. Therefore; any swaying movement of the bowl I during rotation will have the eifect of slightly varying the distance of any point con-' sidered from the axis of rotation, thereby resulting in pressure variations at this point with a decided increase in the impregnating eflect of the liquid on the articles 24. The manner in which this periodic pulsating effect is subject to variation will next be considered.

It is evident from a consideration of Fig. 1 that the rotating bowl I unit is in the nature of an inverted pendulum, and with the bowl stationary, it is obvious that a forceexerted on the bowl I will cause it to oscillate about the bearing II), with the springs, finally restoring the bowl to its upright position. Now assuming that the bowl is rotated with a load in the cage 23 somewhat unequally distributed, it follows thatas the cen-. ter of gravity of the load comes toward one spring I4, it tends to extend it and to compress the spring diametrically opposite, as indicated diagrammatically in Fig. 5. The reaction of a compressed spring I4 tends to compress the spring displaced 90 therefrom, depending on the direction of rotation, which action is repeated by the other springs, and there is thus imparted to the bowl a series of impulses toward and away from the axis of rotation. Obviously, the amplitude of these impulses is dependent upon the strength of the springs or their inital compression by the nuts I5,'-and if all of the springs are initially compressed to a considerable degree, the pulsations of the bowl can be reduced to a minimum. 0n

the other hand, if the compression in one pairof diametrically opposed springs I4 be lessened, there resultsa tendency to increase the inclination of the bowl axis as it rotates, so that for a given .speed of rotation a uniform swaying movement periodic in its nature will be imparted to the bowl with a resulting pulsation of pressure in the bowl to accelerate the impregnating eflect of the liquid on the articles.

I Referring now to Figs. 3 and 4, there is shown in detail an improved'arrangement for providing a liquid tight seal between the cover I6 and the This cover I6 is removable from the bowl I topermit the placing of the article cage 23 therein, and in order to readily lock the cover II in position, the rim of the bowl I provides a locking ring 26Ihaving a plurality of spaced lugs 26a. The outer periphery of the cover in turn provides a plurality of spaced teeth 21 of such width as to fit between the locking lugs 25a, see Fig. 2. By aturning movement of the cover IS, the teeth 21 are adapted to be positioned under the overhanging lugs 26a, thereby eifectively holding the cover IIi in'position. The details of this construction form no part of the present invention and are fully shown and described in the co-pending application of Leon J. -Barrett and Norman F. Holter, Serial No. 471,263, filed July 28, 1930, since issued as Patent No. 1,930,706, October 1'7, 1933. q

While the above described arrangement for locking the cover It in position on the bowl I eifectively prevents accidental removal of the cover I8 while the bowlis rotating, it does not provide a liquid tight seal under the high pressures developed within the bowl I, and the present invention contemplates an extremely eilective arrangement for providing a liquid tight seal between the bowl and the cover. To this end.

q 20,444 'the ring 26 carrying the locking lugs 26a pro,-

' filled with liquid and rotated at high speed, some of the liquid passes through the notches 29a. in

. the lip 29, thereby exerting a pressure on the under side of the sealing ring 30, which tends to wedge the ring tightly between the opposed surfaces of the ring face 28 and the lip 29. Centrifugal force also tends to carry the sealing ring 30 upwardly .and the wedging of the ring 30 increases as the pressure builds up in the bowl 1'. Consequently, while there may be some initial flow of liquid past the ring 30 at low speed, this initial leakage will serve to carry the ring into wedging engagement with the lip, as indicated in Fig. 4. Therefore, by the time the bowl I is up to full speed the compressible sealing ring 30 will make an extremely liquid tight seal,thereby preventing escape of the liquid in any appreciable quantity, in spite of the high pressure developed within the bowl during the impregnating action. When the bowl 1' comes to rest, obviously the pressure holding the ring 30 in position will be released so that no difficulty will be encountered in removing the cover I6. I cover I6, however, leaves the sealing ring 30 in The removal of the position to again seal the bowl upon replacement of the cover and rotatiori of the bowl filled with the impregnating liquid,

In the previous discussion of the operation which causesimpregnation of articles 24 in the cage 23, it ,was assumed that the bowl I was initially filled with the impregnating liquid from the pipe l8, thevalve Ni being practically closed during the rotation of the bowl 1 since the cover seal prevents any appreciable leakage of the liquid once the pressure has been built up. When impregnating certain types of articles, however, it has been found desirable to vary the procedure to the extent of automatically causing the bowl i to empty itself of liquid without interrupting its rotation, with advantageous results, which will hereinafter appear.

To this end, the cover I6 is provided with a series of openings 3| each having a removable closure 32, the openings being arranged just above the lip 29. When it is desired to cause the bowl I to automatically empty itself, the desired number of openings 3| is exposed, after which the cover I 6 is locked in position with the articles in the bowl 1, the valve l9 opened and the machine started. As the pressure builds up in the liquid, it is obvious that centrifugal force will serve to expel the liquid from the bowl through the openings 3| which by-pass the sealing ring 30. After the bowl 1 has come up to speed, the

control valve I9 is turned so as to supplyiust enough liquid through'the .pipe I8 to a little more than compensate for the loss of liquid through' the openings 3| and the amount of liquid ab-- sorbed by the articles. With this mode of operation, the pressure developed in. the bowl I by centrifugal force is just the same as when operating with a sealed bowl, and the circulationgof,

liquid by the pump 21 insures a continuous supv ply through the pipe l8 from the tank 20.

After the desired degree of impregnation has been obtained, the valve I9 is closed with the bowl I still-rotating, whereupon the bowl starts ceptacle.

to empty itself through the openings 3i. Obviously, as long as any liquid remains in the bowl, it will tend to climb up the walls of the bowl and be expelled through the openings 3|, until finally the bowl will be entirely emptied. When this condition is reached, continued rotation of the bowl with the impregnated articles 24 therein will cause the articles to be subjected to a draining actiontending to expel excess liquid conalso be obtained by providing an imperfect seal between the bowl I and cover l6, as by utilizing a sealing ring 30 of more or less permeable mate'- rial, or material having surface channels, such as twisted metal cable.

From the foregoing, it is apparent that by the present invention there is provided an improved method and meansfor impregnating articles of various kinds by various liquids in which the articles to be impregnated are submerged. In the practice of the invention, the articles are subjected to high pressure developed in the impregnating liquid by centrifugal force as the body of liquid with the articles therein rotates at high speed. The pressure developed in the liquid against the walls of the bowl containing the articles acts in such a manner that the impregnating liquid works radially inward from the region of greatest pressure so as to completely expel any air in the articles. Furthermore, the rotating bowl and its driving means, being-movable as a unit about a pivotal axis, is subjected to periodic displacements which have the eifect of setting up a pulsating pressure increasing the degree of impregnation. In practice it has been found that .a breathing eflect is produced by the varying centrifugal force at different speeds and diameters which is effective in obtaining complete impregnation. An additional advantageous feature of the invention resides in the ability of the apparatus to automatically discharge all of the impregnating liquid while the bowl is rotating,

which results in the liquid retraversing the interior of the articles under treatment and the expulsion of excess treating liquid from the articles.

I claim, r

1. A method of treating articles with a liquid for the purpose of impregnating the articles, which comprises rotating a closed receptacle containing the liquid with the articles submerged and positioned therein to build up a hydro-static pressure actingto force the liquid through the articles in toward the axis of rotation of said re- 2. A method 'of treating articles with a liquid for the purpose of impregnating the articles, which consists in subjecting the articles to a pulsating hydro-static pressure developed within a body of liquid by centrifugal force 3. The improvement in the treatment of articles with a liquid for the purpose of impregnating the articles, which consists in rotating at high speed a closed receptacle containing a body of liquid with the articles submerged therein to build up a hydro-static pressure within the liquid,'the

said receptacle being subjected to periodic lateral displacement while .r'otating to cause pulsations of the hydro-static pressure.

4. The improvement inthe treatment of ar receptacle and then discharging the liquid from the rotating receptacle for the purpose of expelling liquid from the impregnated articles by centrifugal action.

5. A method of treating articles with a liquid for the purpose of impregnating the articles, which comprises rotating a closed receptacle containing the liquid to.build up a hydro-static pressure, with the articles submerged in the liquid and so'positioned within the zone of greatest hydro-static pressure as to cause complete penetration of the articles by passage of the liquid through the articles in towards the axis of rotation of said receptacle.'

6 A method of treating loose, relatively porous articles with a liquid for the purpose of impregnating the articles, which comprises rotating 8. closed receptacle containing the liquid with the articles submerged therein and positioned close to the wall of said receptacle where the hydrostatic pressure developedwithin the liquid is the greatest and serves to force the liquid through the articles in towards the axis of rotation ofsaid receptacle. A

WILLIAM A. HYDE.

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