US2319608A - Fluid motor - Google Patents

Description

May 18, 1943 M. KRAUT FLUID MOTOR Filed Nov. '7, 1941 2 Sheets-Sheet 1 INVENTOK,

ATTORNEY.

db o/acemeaf May 18, 1943 M. KRAUT FLUID MOTOR Filed Nov. 7, 1941 2 Sheets-Sheet 2 INVENTOR, Max MW 7,

ATTORNEY.

Published May 18, 1943 FLUID MOTOR Max Kraut, La Libertad, Chontales, Nicaragua,

assignor .to Southwestem Engineering Company, Los Angeles, Calif., a corporation of California Application November 7, 1941 Serial No. 413,156

13Claims.(Cl.121-1G4) W This invention relates broadly to fluid motors and more particularly to a fluid driven apparatus for producing reciprocation of a. member normally'subject to a force acting in one direction. Such motors are particularly'useful in operating jigs for the recovery of minerals, such for examv ple as the improved jigs shown in my co-pending applications Serial No. 228,518, filedSeptember 6, 1938, now Patent No. 2,271,650, issued February 3, 1942, and Serial No. 319,613, filed February '19, 1940, of which this present application is a continuationin part. As disclosed in said co-pending app1ications, a jig is broadly an apparatus comprisinga permeable bed, preferably composed of sand and other 7 particles, supported by, a screen, over which flows a mixture ofwater, gangue, and the mineral desired to be recovered, there beingmeans to provide an intermittent upward now of water through thebed, resulting in a classifying, action therein by which the relatively heavy mineral de- The major object of my invention is to provide simple and efliciemt actuating means which-is capable of imparting a rapid reciprocating motion to a jig or other device desired to be reciprocated, which motion is of suchnature that. the

velocities during upward and downwardstrokes [may be kept approximately constant over ap-' proximately the entire strokes, and the velocity during the downward stroke can be much greater than the velocity during the upward stroke. 1

Another object of my invention is toprovide' become apparent from the followingdescription of different embodiments of'my invention and from the accompanying drawings in which:

Fig. 1 is'an elevational view, partly in section,

showing one embodiment of my invention, the

controlling valve member being shown in the sition in which it is undeflected,

Fig. 2 is a horizontal sectional view of the apparatus of Fig. L'tak'en along the line 2-2, V

Fig- 3 is a diagrammatic view showing the controlling valve in its uppermost position,

' Fig. 4 is a view similar'to Fig. 3. but showing the valve in its lowermost position.

Fig. 5. is a-vertical sectional view of a. modified form-of fluid motor embodying my invention, the controlling valve member being shown in the position in which it. is undeflected,

Fig. 6 is an enlarged sectional view of the bellows forming a part'of the motor shown in Fig. 5, Fig. 7 is a partial sectional view of the fluid motor of Fig. '5, showing the controlling valve in its lowermost position,

Fig. 8 is a view similar to Fig. 7, but with the valve in its uppermost position, and g Fig. 9 is a diagram illustrating the manner of variation of displacement of the moving parts of my fluid motors with time.

Referring now, to the drawings, and particularly to Figs. 1-4 thereof, the numeral I0 designates a vertical shaft or rod adapted to be attached to the body to be reciprocated, in the case of a jig, this being the collecting .pan. Under normal conditions,=the rodlfl willtendto move downwardlyin response to the gravitational pull thereon. The rod I0 is movably mounted, and is adapted to be reciprocated in 'a vertical path as will nowbe described. a

An outer cylindrical housing II is secured to a bridge-like structure 12 adapted to span a jig or otherapparatus'fromside to side in convenient manner. Within the housing H is locateda cylinder l3 attached to the housing II at circum- 'ferentially spaced locations and opening at top and bottom into the housing I I. A water supply pipe 34 is screwed intothe housing II and cylinder I3 and feeds water under pressurev directly into thecylinder' 13. The cylinder 13 at its lower end is conical in shape and serves as a valve seat l4 for a circular valve disc 15 of resilient ma terial, such for example a rubber,j.which i preferably of tapering cross-section, facilitating flexing of the disc. ,4 piston 16 closely fitting the cylinder I3 is adapted to move-therein above the water inlet pipe, 34. The piston l6 and valve member liaremounted on an axial tube ll,

- being pressed against the shoulder It by the tighteninglof nut l9, The valve disc 15 has'an area less than that of the piston; l6 and i mounted so asto be unsupported in its peripheral portion. The tube ll extends upwardly through a bearing 20 mounted in .acover 2| secured to the top of housing H by bolts 22. A lubricating fitting 23 is connected through the cover 2| to conduct lubricant to the bearing 20.

A diaphragm 2|, preferably of rubber or can vas, and apertured to permit tube H to pass therethrough, is clamped between housing I i and cover 2| to protect the bearing 20 from splash of water. The rod ll! passes through the tube IT, has a shoulder abutting the lower end of tube II, and carries a nut 25 in threaded engagement therewith at its upper end which securely clamps the tube I1 and associated parts on the rod N for movement therewith. A spring 26 surrounds the tube l1, bears-at one end onpthe cover 2| and at the other end against a. washer 21 retained in an adjustable position by nut 28 in threaded engagement with tube II. The spring 26 acts to balance part of the load on rod ill due to the weight of the rod I and its associated parts, whereby the pressure and amount of fluid required to operate the reciprocating means is re- 7 duced. It should be noted that the spring 26' should never be made sov strong as to completely balance all the load on rod 10, for then auxiliary means would have to be supplied to return the valve to the closed position. Attached to the housing II at its lower end and in communication with .the' space within, the

' housing II and cylinder [3 is a fitting 29 having a side outlet pipe'30 connected thereto and a pipe 3! connected to the bottom, surrounding rod l0, there being space left between the rod lliand pipe 3l.- The pipe 3| may pass downwardly through the piston II to be pulled rapidly downward by the weight of rod l0 and its associated parts. As soon as the piston and valve structure has.

fallen to a point where disc contacts seat i4, pressure starts to buildup again in cylinder I3. Since, however, the disc I5 is flexible,'it can be distorted into the shape shown in Fig. 4 in which condition the volume within the cylinder between piston l6 and valve disc i5 is greater than in the condition illustrated in Fig. 1. It will be obvious that pressure cannot build up to a normal value within the cylinder so long as this volume is increasing. For this reason, the piston l6 and valve disc l5 sink to a lowermost posiiton illustrated in Fig. 4. The pressure within the cylinder then builds up quickly and causes the piston I6 the bed of the jig and into the hutch, if the motor isbeing used to operate a, jig.

In the bottom of fitting 29 is preferably located a washer 32, preferably of rubber, clampedbetween a shoulder of the fitting and a nut 33 in threaded engagement with the fitting. The washer 32 may pack the rod lll'in contact therewith to prevent passage of any fiuid'into the pipe to be raised while the periphery of the disc I5 is held in contact with seat ll, the piston and disc going through the position shown in Fig. 1 and on through the remainder of the cycle as previously described. Since any momentum possessed by the moving parts at the time of unseating of the valve disc I; is quickly overcome by the unbalanced force of gravity, there is very little upward movement after this time, and nearly all of the upward stroke of the member I! takes place while the valve disc 15 is seated on the seat l4.

The water discharged from the cylinder past the disc l5 when in the open position passes'into the fitting 29 andout through pipe 30, a portion The diaphragm shield 2| prevents any of this water from splashing up-into the bearing 20.

3| or it may be of'any suitable internal diameter to permit'passage of any desired proportion of the available fluid past the washer, pipe II and into the hutch.

In the. operation-of this form of my actuating means'to reciprocate therod l0, liquid, preferably water; .under pressure enters cylinder 23 through pipe 34 and acts upon both piston l8 and disc ll,'the force on piston IS in an upward direction being greater than the downwardly directed force on 'the valve member 15 by reason of the greater area of pistonl8. The piston 18 therefore moves upwardly; If the disc [5 were infiexibleit would also move upwardly coincidentally with piston I 6; but being flexible, the

periphery of disc I 5 is held down in contact with the conical seat I while the center of the disc connected to piston l6 rises with the piston, as

through the shown in Fig. 3. The piston it continues to rise y until a. critical point is reached where the pein contact with the seat H by the water pressure, and the disc 15 then breaks from the seat.- The valve disc snaps open quickly as the pressure on opposite sides of it quickly equalizes. At the same time the piston it moves farther up in the cyl-' inder due to the momentum it has acquired. Thus the opening closed by disci is rapidly opened, resulting in an instantane'ous'drop in pressure; which, among other things, depends ing between the seat ll and-the disc 15 causes 75 strokes. It-is to be riphery of the disc I5 can no longer be'held The resulting reciprocation of rod [0 is very rapid and regular. The'number of strokes perminute may be adjusted by varying the diameter of the disc I! or by varying the restriction of the water supply. In one embodiment of this form of my device, about 200 complete cycles per minutewere obtainable with a disc 5 inches in diameter,-and with a disc- 4' inches in diameter thenumb'er of cycles could be adjusted from 400 to 1000 per minute, finally reaching a vibratory movement. 'The extent of the movement depends'uponthe diameter of the disc l5, greater movement being obtained, within limits, by use of a disc of a larger diameter. In the device above referred to, amovement of 1 inches was obtained by use of a'disc 5 inches in diameter, while a movement of /4 inch was obtained by use of a disc of 4 inches in diameter.

The movement of the piston I 6 is relatively I slow on its upward stroke because a relatively large weight is being lifted by the water pressure acting only onthe differential, area of piston l6 and disc ill, while on the downward stroke the weight connected with rod Ill pulls the piston down veryrzp'idly against a greatly reduced pressure. upward and downward velocities of the member l8 and associated parts are approximately constant over. approximately the entire stroke thereof. This type of reciprocation involving a rapid downward stroke of constant velocity and' a relatively'slow upward stroke of constant vev locity has been found to be particularly well 1 adapted to operation of a jig, resulting in more emcient. recovery than with reciprocation of equal velocity on. the two oppositely directed understood, of course, that It is found by actual test that both the Y the reciprocating means herein. disclosed may 54 is connected a fltting 28 having a side disbe advantageously employed in jigs of'various constructions and may also be used for purposes other than reciprocation of a jig. Referring now to Figs. to 8, wherein is illustrated a modified form of fluid motor actuating means embodying my inventiomthe numeral II again indicates a housing which may be secured to a bridge-like structure l2 spanning-a jig from side to side or. attached to other means to beoperated. The housing II is at its lower end preferably conical in shape and serves as a valve seat H for a resilient valve disc 48, preferably of rubber, which is connected for movement with.

the rod ID. The valve disc 48 may be clamped between a shoulder on the sleeve member I .and a nut l9, and the sleeve member |'|.may be held against a shoulder on the rod IO' by means of a sleeve member 52 on the rod I0 and a nut 25 threadedon the upper end of therod Ill.

The valve member 48 in this form of my in-. vention is preferably of tapered cross-section, being thin nearthe center support to provide flexibility, and thickest at theperipheral edge to prevent the valve member from passing through the outlet .54 from the housing. I find that when I use a valve member 48 having a thick edge, asshown, it is possible to considerably increase the size of the outlet 54 over that which is possible when using a relatively thin-edged valve member such as-that previously described herein, and still keep the valve member from passing through the outlet on the 1 downward stroke. It will be evident why thisis so from an inspection of Fig. '7 in which the valve memher is shown in its lowermost position. It will be observed that in this position the lower peripheral edge of the valve member is. forced even farther out radially than when the valve member is undeflected. Thus, a tendency of the valve member to pass. through the outlet 54 on the downward stroke is averted;

A bellows55 of. flexible material, preferably rubber, and of diameter-larger than the valve member 48, is housed within the housing I, having its upper end .clamped between the housing H and a cover 2| and its lower end attached to a plate 51 clamped between the sleeves l1 and 52. The bottom of the bellows thus constitutes a movable wall of the fluid chamber, similar in effect to the movable wall piston l6 of Fig. 1. Within each of the outwardly extending folds of the bellows 55, for lateral reinforcement of the bellows, I preferably place a metal ring 58, and fall of the rings 58 are preferably held in place by means of a plurality of strips 68 offlexible material, preferably'rubber which are vulcanized or otherwise secured to the insidesurface of the bellows so as .to cover over the rings 58 at locations circumferentially spaced around the bellows. A hole 6| is located in the cover 2| to permit air to freely move into and out ofthe space within the bellows 55.

The sleeve'52 is slidably guidedin a bearing in the cover 2|, and a compression spring 26 surrounds the sleeve 52 and at one end abuts the cover 2| and at the other end abuts a nut 28' threaded on the sleeve 52. The spring 26 acts to balance part of the load dueto the weight of the parts supported by rod l0.

A water inlet pipe 34, provided with a control valve not shown, discharges into the chamber formed within the housing H at a point between the valve member 48 and'the bellows 55. To

the outlet end'of the housing I below the outlet charge pipe 30 connected thereto and a pipe 8| connected tothe bottom thereof and surrounding the rod l0. Space is left within the pipe 3| around the rod I0 for-the passage of water. The pipe 3| may pass downwardly throughthe bed of a jig'and open into the hutch thereof when my device is being used in connection therewith. In

' tion of the motor.

the bottom of the fitting 28 is located a washer 32, preferably of rubber, clampedbetween a shoulderof the fitting and a ,nut 33 in threaded engagement with the fitting. The :washer 32 may pack the rod ID in contact'therewith to prevent passage of any fluid into the pipe 3| orit may beof any suitable internal diameter to permit-passage of any desired proportion of the available water past the washer, and through the pipe 3|.

I have found that water which is passed through the motor generally contains air which is to some extent released within the housing l and accumulates in the uppermost portion of the so as to continuously pass a small stream of water which effectively sweeps airwout of the fluid chamber of the motor and preventsits accumulation therein.

'In the operation of this form of my fluid motor to'reciprocate the-rod ID, a fi'uid,'preferably water, underpressure enters through the pipe 34 and acts upon both the-valve member 48 and the movable wall comprising the plate 51' and the 1 under side of the bellows 55, the force on the latter being'greater than that on the valve member 48 by reason of the greater area acted upon.

The rod- I0, is, therefore, moved upwardly. Since the valve member 48 is flexible, the periphery thereof continues to be held down against its seat by water pressure while the rod 10' moves upwardly. The rod Ill continues to move upwardly until the valve member '48 is deflected 'to such an extent that the water. pressure on it can no longer hold its periphery on the seat; M.

The conditions existing at this moment may be as illustrated in Fig. 8. Following a slight additional upward movement of the rod III, the periphery of the valve member 48 will, snap up:

- instantaneous drop of the pressure beneath the wardly by reason of its'resi'lience and open a passageto the outlet 54. Water then immedi'- ately' rushes out of the outlet 54 and there is an bellows 55. The'heavy weight of the rodl0 and its associated parts oauses'the rod' I8 to drop rapidly. When it has fallen to a point where the valve'member 48 contacts'the seat I4, pres-- sure starts to buildup again in the fluid chamher, but because of the momentum of the-moving parts, they fall to a'point where the. conditions may be as illustrated'in Fig. '7.

movement and starts to move the bellows 55 and rod l0 upwardfthe motor again going through the cycle described above. The reciprocation of At this "point fluid pressure has overcome the downward the rod Ill may be made slow or rapid as desired by control of the'valve on pipe 34.,

It is important to note that in the action of the fluid motors of my invention, any substantial movement of the movable wall comprising the piston ll; of Fig. 1 or the plate 51 and the bottom of the bellows of Fig. 5 results in a corresponding movement of the rod l0, and that the valve member I5 or 48, as the case may be, is sufficiently flexible so that while the valve member is still closing the outlet the rod in is permitted to move through nearly its full stroke in the upward direction.

The water which is discharged from the motor passes into the fitting 29 and out through the pipe 30, a portion thereof, depending upon the opening between the washer 32 and the rod l0, passing down the pipe 3| to supply make-*up water to the hutch.

The type of reciprocation resulting from the operation of the motors herein described .is di,-

agrammatlcally illustrated in Fig. 9 and is characterizedby relatively slow upward strokes AB, CD, EF, etc., during which the displacement varies sub-stantialy uniformly with time, and relatively rapid downward strokes BC, DE, FG, etc., during which the displacement varies substantially uniformly with time. Thus, both the upward and downward velocities of the rod l0 and the water in the hutch of the jig are approximately constant over approximately the entire stroke, while the downward velocity is much greater than the upward velocity. The importance and value of these velocity conditions is evident from the following analysis. I

In order to'maintain the permeable bed of a jig in a state orsuspensi'on and to secure the greatest amount of work from the jig per unit of time, it is desirable to move the water upwardly and downwardly through the bed with a relatively large number of alternations of movement per unit of time. But topermit high recovery of fine concentrate particlesfit is desirable to employ not, too great an upward velocity of water. The most eflicient condition, therefore, is one in which the downward velocity of water is considerably greater than the upward velocity of the water, for by this means the upward velocity may be limited to an eflicient value and the number of strokes per unit oftime may be maintained large- If,vhowe'ver,' the downward velocity is too great at any time, the bed tends to pack too severely, so it is clear that with a given maximum amount of water desired to be moved downwardly and a definite limit placed upon the maximum instantaneous downward velocity, the most efficient condition will be that in which the downward velocity is approximately constant over approximately the entire period of downward movement. By this means a sumciently rapid alternation of movement is secured to maintain the bed in an efllcient condition and it is prevented from packing severely on the downward stroke. It will also be evident that the most efllcient condition during the upward stroke is one in which the velocity is approximately constant over approximately the entire stroke because for any other condition during these periods when the velocity is higher than the most suitable velocity, proper recovery of fine concentrate particles is being hampered, while during those periods when the velocity is less than the permissible value, time is simply being wasted and could better be employed in increasing the number of alternations per unit of time.

From the foregoing it will be seen that both of the embodiments of my invention herein described are capable of attaining the objectsand accomplishing the advantages hereinbefore set forth, and it is to be understood that I do not mean to be limited to any of the specific showings herein except as limited by the claims appended hereto.

I clalm as my invention:

1. Apparatus for producing reciprocation of a member normally subject to a force acting in one direction, which includes: a cylinder having an outlet at one end; a piston movable in said cylinder and connected to said member in such manner that movement of said piston results in a corresponding movement of said member; a flexible valve disc of area less than that of said piston and connected to said member, said valve disc being adapted to close said outlet upon movement in response to said normally acting force and being sufliciently flexible to permit material movement of said" member while still closing said outlet; and fluid supply means connected with the interior of said cylinder between said piston and said valve disc.

2. ,;Apparatus for producing vertical reciprocation of a member urged downwardly by the force of gravity on ;said member and its associated parts, which includes: a spring acting to partially balance said force of gravity; a cylinder having an outlet at the lower end; a piston movable in said cylinder and connected to said memher in such a manner that any substantial movement of said piston results in a corresponding movement of said member; a flexible valve disc of area less than thatv of said piston and connectedto said member, said valve disc being adapted to close said outlet upon downward movement. and being sufficiently flexible to permit 'material movement of said member while still closing said outlet; and fluid supply means connected with the interior or said cylinder between said piston and said valve disc.

, 3. Apparatus for producing reciprocation of a member normally 's ject to a force acting in one direction, which includes: a cylinder having an opening at one end and a conical surface adjacent said opening; a ,piston movable in said cylinder and connected to, said member in such -manner that movement of said piston results in corresponding movement of said member; a flexible valve disc of area less than that or said piston and connected at its center to said member, said valve disc being adapted to engage said conical'suriace to close said opening upon movement in response to said normally acting iorce and being sufficiently flexible to permit material movement of said member while stillclosing said outlet; and means for supply- .ing fluid under pressure to the interior of said a piston movablein saidcylinder and connected to said member in such manner that movement of said piston results in movement of said member; a flexible valve disc of area less than that of said piston and'connected at its center to said member, said valve disc being adapted to engage said conicalsurface to close said opening upon downward movement; and means for supplying fluid under pressure to the interior of said cylinder between said piston and said valve disc.

5. Apparatus for producing vertical reciprocation of a member urged downwardly by the force of gravity on saidmemberand its. associated parts, which includes: a housing open at its lower end; [a cylinder contained within said close said opening upon downward movement and being sufflciently flexible to permit material movement of said'memberwhile still closing said outlet; means for supplying fluid to the interior of said cylinder betwee'nsaid piston and said valve disc; a cover attachedto the top of said housing through which said memberfiextends; a' bearing in said cover serving as a guide for said member; and a shield clamped between said housing and said cover positioned between the top of said cylinder and said bearing and apertured to permit said member to pass therethrough.

6. Reciprocating, apparatus, which includes: walls forming a chamber provided with an inlet and an outlet for fluid, one of the walls of said chamber being movable; a reciprocable I member connected to said movable wall in such manner that any substantial movement of said movable wall results in corresponding movement of said member; a valve element of area less than that of said movable wall and associated with said reciprocable member to normally close said outlet, said valve element being adapted to continue to close said outlet during initial movement of said reciprocable member in a direction corresponding to outward movement of said member normally subject to a'force acting in one direction, which includes: walls forming, a cham her having a fluid inletand'a fluid outlet, one of said walls being a movable wall positively connected to said member in such manner that an increase in the volume of fluid in said chamber causes a proportional movement of said memher; and a flexible valve disc of area less than that of said movable wall connected to said member, said flexible'valve disc being adapted to close said fluid outlet upon movement of said member in response to said normally acting force and having an unrestrained area capable of'distortion to maintain said fluid outlet closed throughout substantially the entire stroke of said member caused by increase in the volume of fluid in said chamber; I

9. Apparatus for producingreciprocation of a member normally subject to a force acting in one direction, which includes: a cylinder having an opening at one end and a conical surface adjacent said opening; a piston movable in said cylinder and positively connected to said member in such manner that an increase in the volume of fluid in said cylinder causes a proportional movement of said member; a flexible valve disc of area less than that of said piston and connected at its center to said member, said valve disc being adapted to engage said conical'surface to close said opening upon movement in response to said normally acting force and having an unrestrained area capable of distortion to maintain said fluid. outlet closed throughout substantially the entire stroke of said member caused by increase in the volume of fluid in saidcylinder;

'and walls forming a passage for inlet of. fluid into the interior of said cylinder between said piston and said valve disc.

10. Apparatus for producing vertical reciprocation of, a member urged downwardly bythe force of gravity on said member and its associated parts, which includes: a spring compressed between said member and a stationary part 01' said apparatus acting to partially balance said force of gravity; means for adjusting the force exerted by said spring; a stationary housing; a cylinder contained within said housing and supported thereby at circumferentially spaced locations,

said cylinder having an opening at its lower end movable wall but to be unseated by continued movement of said reciprocable member to open said outlet.- v

7. Apparatus for producing reciprocation of a member normally subject to. a force acting in one direction, which includes: walls forminga chamber provided with an inlet and anoutlet for fluid, one of the walls of said chamber being movable and connected to said member in such manner that any substantial movement of said movable wall results in corresponding movement of said member, and a flexible valve disc of area v 8. Apparatus for producing reciprocation of a and a conical surface adjacent said opening; a piston movable in said cylinder and positively connected to said member in such manner that an increase in the volume of fluid in said cylinder causes a proportional movement of said member; a flexible valve disc of area less than that of said piston and connected at its center to said-memher, said valve disc being adapted to engage said conical surface to close saidopening upon-downward movement and having an unrestrained area capable of distortion to maintain said fluid "outlet closed throughout substantially the entire stroke of said member caused by increase in the volume of fluid in said cylinder; and means for supplying fluid under pressure to the interior of said cylinder between said piston and said valve disc.

11. In a water-driven reciprocating means the combination of: a housing providing a water chamber within, a waterinlet to said chamber on the side of said housing, and a water outlet at the bottom of said housing; a bellows secured at the top of said housingand extending into said chamber; a reciprocable member attached to the bottom of said bellows; a resilient valve'member connected with said reciprocable member and the bottom of said housing; a bellows secured at the top of said housing and extending into said chamber; a reciprocable member attached to the bottom of said bellows; a resilient valve member connected with said reciprocable member and adapted to close said outlet upon downward movement of said reciprocable member, said valve member being of area less than that of the bottom of said bellows; a conduit in communication with said chamber adjacent the highest point thereof and extending in an upward direction from said chamber; and a control valve in said conduit located at an elevation higher than any point of said chamber.

13. In a fluid-driven reciprocating means including walls forming a chamber provided with an inlet and an outlet for fluid, one'of the walls of said chamber being movable, and a reciprocable member connected to said movable wall in such manner that any substantialmovement of said movable wall results in corresponding movement of said member; a valve disc of resilient material of area less thanthat of said movable wall and connected to said member, said valve disc being adapted to close said outlet upon downward movement and being of tapered crosssection with the thickest unsupported portion of said valve disc being located at the periphery thereof. .e

MAX KRAUT.

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