US1507520A - Pump for liquids - Google Patents

Description

Sept. 2, 1924. 1,507,520

w. J. RUSDELL PUMP FOR LIQUI DS Filed July 14. 1921 N 2 Sheets-Sheet 1 Sept. 2, 1924;

w. J. RUSDELL PUMP FOR LIQUIDS Filed July 14. 2 Shaets-Sheet 2 William Jzzwdzz flwrmyi Patented Sept. 2, 1924.

UNITED STATES PATENT OFFICE.

v PUMP FOR LIQUIDS.

Application filed July 14, 1821. Serial No. 484,818.

T 0 all whom it may concern:

Be it known that I, WILLIAM JOSEPH RUsDELL, a subject of the King of Great Britain, residing in Wolverhampton, England, have invented certain new and useful Improvements in Pumps for Liquids, of which the following is a specification.

My invention relates to im rovements in that type of pump for liqui s in which a reciprocating piston (this term including a. plunger, bucket or the like) moves a column of liquid so that it acquires momentum suffi' cient tokeep the column in movement after the termination of the power stroke and so that more liquid is drawn in by the moving column in the direction of flow and the valve or valves are closed only during the power portion of the stroke of the piston in question.

By the invention a pump of this kind is so constructed that the piston or part of it can move, during the power portion of the stroke, at a speed independent of that of certain parts of the driving mechanism.

In the known pumps the motion of the piston usualy tends to be approximately harmonic, being derived from reciprocating driving mechanism comprising a rotating crank. The motion of the liquid on the other hand tends to be continuous.

Herein lies a defect, since the piston moves at a speed which varies during the power stroke while the speed of the liquid is substantially constant so that the impulse is applied by the piston only through a comparatively small portion of the stroke and shocks are liable to occur. I

By this invention this defect is mitigated by making it possible for the piston to follow the movement of the liquid during the power portion of a stroke so that the impulse is applied more uniformly and may be prolonged through a considerably greater portion of the stroke than is the case when the piston must follow the speed of the driving. mechanism.

The object may be obtained by the interposition between parts that reciprocate, of elastic devices. Thus in the commonest case there is a shaft tending to be rotated uniformly by an engine, a crank fixed to the shaft and the pump piston connected with the crank by the usual linkwork, forming akinematic chain,the motion of the reciprocating parts being directly governed by the rotating shaft. By the invention the said elastic devices are introduced into the kinematic chain somewhere between the rotating shaft and the piston or that portion of the piston which acts directly on the liquid. For instance, the piston may be in two or more parts with the elastic device between them, one or more of the parts may be itself the elastic device for instance, an air cushion on the end face of the piston; or the said device may be between the piston and the piston rod or connected parts, or between the shaft and the crank or in the crank itself.

During the period of impulse when the reciprocating parts tend to move faster than the liquid column, the elastic devices allow relative motion to occur and energy is stored by the elastic devices to be liberated a ain during the latter part of the impulse w en the disp'aced parts regain their normal relative positions.

By using two or more pistons, each having elastic devices, the work may be uniformly shared between them although they operate to impart impulse simultaneously in the same direction. Suitable multiple pistons may be contrived to operate in succession so as to. reduce the length of the periods between the impulses or to eliminate such periods, that is, to obtain in effect a continuous impulse of almost constant intensityan exceedingly valuable result especially for high lift pumping. In the case of pumps having only one piston, only one valve or one set of valves is necessary,

but for the purpose of priming,-for start ing up, a foot valve may sometimes prove useful.

Theforegoing eneral statements will be further illustrate by reference to the accompanying diagrammatic drawings showing in Figures 1 to 15 sections and partial sections of several forms of pum s and accessories thereto in accordance wlth the invention.

Fig. 1 shows a part section of a simple form of pump. The bucket 1 having valves 2 works in a cylinder or barrel 3. Beneath the bucket is a spring 4 which at its lower end rests on or is held by a ring 5 attached to a cross-head 6. The latter is rigidly connected by rods 7 with the cross-head 8 and pump rod 9 which has vertical reciprocating motion. The rod 10 rigidly attached to cross-head 6 slides through a hole'13 in the bucket 1 and carries a collar 11 sliding in a cylindrical extension 12 of bucket 1,

thus keeping the latter normal to the axis of the barrel 3. Beneath the collar 11 1s a spring or buffer 14. h

The barrel 3 is expanded below its cylinder portion, as indicated, to form a bell sha ed mouth facilitating introduction of the ucket.

Above the barrel is a taper pipe 15 and a pipe 16 of smaller diameter than the barrel and of suflicient length to provide the necessary mass of the liquid column.

The liquid columnconsists of the whole of the moving liquid in barrel 3 and pipes 15 and 16, but the liquid in pipe 16 1s usually the main portion. The barrel in this case is of larger diameter than the pipe 16 to allow of suitable valve area in the bucket and to reduce the velocity of liquid through the valves 2.

The operation is as follows It is assumed that the ump is work ng normally, the rod 9. deriving its motion from a crank rotating uniformly. It' 1s also assumed that the liquid column 1n barrel 3 and pipes 15 and 16 is moving with approximately uniform velocity in the direction of the arrow. Assume now that the cross-head 6 and attached parts are at their lowest positions, and that bucket 1 is also at its lowest position in the barrel 3, all the parts just referred to being momentarlly at rest with the crank on the dead centre. The bucket 1 will be in the position shown with respect to the rod 10, collar 11, and springs 4 and 14; valves 2 will be open to allow the liquid drawn upwards by the momentum of the liquid column to pass through the bucket.

The cross-head 6 now begins its upward stroke with gradually increasing velocity, and the spring 4, preferably under initial compression, carries the bucket 1 upward with motion similar to that of cross-head 6. The upward velocity of'the liquidthrough and with respect to valves 2 gradually decreases until, at the moment when the velocity of the bucket attains that of the liquid in barrel 3, no liquid passes through the valves which thereupon close in any known manner such as under the action of springs or elastic material.

The velocity of cross-head 6 now soon exceeds that of the liquid in barrel 3 and under the action of spring 4 the bucket exerts pressure against the liquid above it, thus giving an impulse.

Although the velocity of the liquid column may a little later increase slightly due to the impulse itself it will not alter in direct proportion to the velocity of the cross-head 6, nor is it desirable that it should do so; the spring 4 is, therefore, still further compressed, thus storing energy and allowing the cross-head '6, rod 10 and other momentum of the bucket.

attached parts to move upward relatively is complete and the valves 2 again open to permit passage of liquid through them. At \the moment when the bucket regains its top position with regard to cross-head 6, it is moving with a certain velocity relatively to the collar 11, and the spring or buffer, 14 preventsor minimizes the shock which might otherwise occur, due to the proporto per- The springs must be of suitable tions for the functions they have form, especially spring 4.

As this spring becomes further compressed during an impulse the pressure exerted against the bucket, in turn to be exerted against the liquid column above it, will usually, also be increased, but by the use of a suitable spring and initial compression this variation of pressure need not be large, so that there .is a more or less' uniform pressure during the period of impulse. After the valves 2 re-open. and during the return stroke the velocity of liquid through the valves increases to a maximum approximately at the moment when the cross-head is travelling downwards at its maximum velocity. Thereafter as the velocity of cross-head and bucket decreases, the velocity of the liquid through the valves decreases until at the dead centre of the crank the cycle of operations is completed.

In starting the pump from rest the pipes 16 and 17 and the barrel above the bucket may be'primed by filling or partly filling with liquid. If the head a-a of the liquid to be pumped is sufiiciently high, it may lift the valves 2 and prime the pump sufficiently for starting. r

The action in starting from rest is similar to that just described except that at the slower velocities and with a shorter liquid-- during the return stroke of the bucket.

By disconnecting rod 9 from above or disconnecting rod 7 from cross-head 8 and lowering the bucket clear of the lower end of barrel 3, the bucket and its valves are very readily removed for inspection and repair. The leakage of liquid past the bucket and rod 10 is prevented or reduced to a minimum by the usual methods of packing.

The modification shown in Fig. 2 avoids 'thefperforation 13 of'Fig. In this case -14 in Fig.1.

used instead of spring, in'

--There are many positions w ere springs giving the required efiects may be ,m-

troduced. -Thus in Fig. 3 the upper end of.

cylinder 12-"isfpartIy closed to retain a spring 4* between the closed endandcollar 11. -Generally Fi' I 1, but cross-hea 6,'rods 7, cross-head 8 and rod 9 are'elastically connected by ntroducing springs 4, 14; 4", 14"; '41, 14; and 4, 14respectively. Springs 4",;4", 4,4 and 4 act to assist spring 4 or one or more such s rings may be used. instead of s'pring4.

to spring 14. V Flg. 4 shows a somewhat'modified and n some respects simpler arrangement. As before the bucket 1 provided with valves 2 works-in barrel 3. In this case the crossheads 6 and 8 are dispensed with, and the rod 10 is extended upwards above collar 11 as pump rod 7 to serve the same purpose as rods 7 and 9 in Fig. 1. Rod- 7 slides in a gland 17 in the pipe 15. Springs 4 and 14.

0 rate similarly to springs 4 arid 14 respectively in Fig. 1, but othersprings or suitable elastic devices may'be used instead" or in' supplement.

Fig. 5 shows in section a type of bucket allowing a large valve area relatively to the diameter of the barrel 1. series of similar. annular parts of increasing dlameter 20, r

Rings 2, 2", 2 and 2 of suitable flexible and elastic material, lie on the upper-fiat surfaces of 20?, 20", 20 and. 20 and form the valves corresponding with valves 2 in Fig. 1. When liquid passes through the valves the rings 2, 2", 2 and 2 lift. and

turn upwards against the curved annular stops 18 18', 18 and 18.

After the passage of liquid the elasticity ofth e valves causes them to resume their normal flat -shapeand return to their seats.

The bucket leather or cup 24 is shown held in osition between parts 21 and 22. The who e bucket may slide on rod 10 fixed to cross-head 6 not shown, which keeps it normal to the barrel,

Fig. 6 shows in section a pure valveless plunger, the valves 2 for 'quid be- 3 is very similar to Fig. I

.prings 14', 14", 14, 14 and 14'have similar functions with a ing a. stationary partition 25'held betweenslides in a gland 17 in pipe 16 and through ..;the ends of offer the minimum of resistance to the mo'viston 1., which are shaped to In normal operation theaction'is practically the same as that of Fig. 1. I

.The spring 4 is compressed and re-expands during an impulse whilst the valves 2 remain closed. Spring 14, similarly to spring 14 in Fig. -1, serves as a buffer to .check the motion of thepi'ston 1 when the latterattains its top position relatively to rod 7. It will be. noted that thepiston slides on rod 7 during the compression and expansion of spring 4.

The liquid'may be raised from levels considerably below the valves 2, as at aa, by

providing a suction pipe 27, and as already mentioned' a foot valve or valves 28 are sometimes useful for priming the pump with l liquid for starting; during the normal operation, of the pump these valves remain open, and allow the continuous passage of liquid.- It is obvious that in a case where a bucket having valves is used, there may be additional valvesin a stationary partition as in Fig. 6, and that there are many other ways than those shown by .which the springs or elastic devices can be provided.

When-cross-head such as 6 and 8. in Figs.

1 and 3 are used, they may themselves be formed of leaf springs to assist the other elastic devices, if any. Thus, in Fi 7 the rod 9 corresponds with rod 9 ofig. 1 and leaf spring 4, fixed to the end 8 of rod 9, acts as cross-head, and serves a similar purpose to that of spring 4 of Fig. 1.. Buffer springs 14 serve the purposes of springs 14 in Fig. 1 and the bar 11 sliding on rods 7 performs the functions of collar 11. As'in the? case of spring 4 of Fig. 1, it is desirable that there shall be initial tension'in spring 4*. 4

It has already been mentioned that during the compression of springs 4. 4 and elastic devices imparting the impulse, a-useful purpose is served if the impulse is as constant 7 as possible. Usually when an elastic device is compressed, or its'configura tion is altered, the pressure alters as the distortion increases. This may be minimized or entirely eliminated by systems of levers with or without cam and like devices. As an example of the latter, the

fusee wheel of a spring clock or watch may be given.

In Fig. 8 is shown a convenient arrangement forifixing a pump, of the kind shown in Fig. '1, to a well or pit. Two arallel beams or joists 29 are fixed to a wal of the pit and the barrel 3 is assumed to be pro-- vided with suitable external brackets which are bolted or otherwise fixed to the beams '29 near their lower end.

- latter is also very conveniently fixed to the upper ends of beams 29.

The pipes 15 and 16 are fixed to and rest on barrel 3. The ump is driven by driving belt 34 and be t pulley 35.

In the illustrations so far described, the elastic devices have been one of the simplest, namely, metal springs, but an other suitable type of spring can'be use for instance,

pneumatic cushions which have advantages for large pumps.

In Fig. 9 such cushions are shown, rod 7 corresponding with rod 7 in Fig. 4.

Plate 36 attached to lower end of pump rod '9 slides onthe parallel rods 38, which secure at definite distance apart, plates 37 and 39, the former being connected with the upper end of rod 7. I

Between plates 39 and 36 are four pneuma-tic tubes 4, inflated to the re uired de gree, and a similar tube 14 is s own be-- tween plates 36 and 37.

During an impulse to the liquid column the inflated cushions 4 act quite similarly to the springs 4 in Fig.1, except as may be modified by the momentum of the solid parts between the cushions and the bucket,

and the cushion 14 serves a similar purpose ,to that of spring 14.

During compression of the cushion, the plates 39 and 36 slide on rods 9 and 38 respectively. Parts 40 represent guides to prevent displacement of the cushions.

The cushions 4 may be interconnected or connected in common with a reservoir thus allowing the pressure of inflation to be more constant during compression.

By interposing suitably shaped distance pieces between the cushions as at 41 in Fig. 9 a still more uniform tension on rod 7 may be obtained, for if the pressure in cushion 4 is approximately constant during compression of the cushions the effective area in contact with distance pieces 41 alters very little, and thus the total lateral pressure will remain as constant as desired.

Tn Fig. 10 4 represents inflated cushions under initial pressure, either quite separate. or for convenience communicating with each other, and if desired to obtain more uniform pressure, all communicating with a common reservoir. They correspond with air cushions 4 of Fig. 9, and the inflated cushion 14, in this case annular, like 14 of Fig. 9, serves the purpose of a buffer cushion. Rod

9 corresponds with rod 9 in 7 with rods 7 in Fi 1.

Fig. 11 illustrates ow the bucket 1 can be operated directl b air cushions. As in Fig. 1, the cross-lies. 6 is fixed to rods 7 and bucket 1 slides in barrel 3, the inflated cushions 4 being held between bucket 1 and cross-head 6 in similar manner to spring 4 in Fig. 1. Rod 10, collar 11, sprin 14 and cushions 4 serve similar purposes to t e parts of like numbers in Fi 1.

Other inflated cushions 42 between the bucket 1 and a flange 43' projecting from barrel 3, may suflice by acting as a spring to arrest, by compression, the upward motion of the bucket at the end of its stroke, and by re-expansion to cause the downstroke, thus Fig. 1 and rods assisting or dispensing with the functions of parts 10, 14 and 11.

Also if the degree of inflation of 42 is sufficiently small during an impulse the liquid pressure may compress the cushions, so that the compression and subse uent expansion will supplement the efiect 0% cushions 4.

It should, be noted that if the bucket is suitably guided, and if the surfaces of cushions 42 in contact with each other and with flange 43 and bucket 1 are liquid tight the barrel 3 may be dispensed with below flange 43 and all sliding and rubbing eliminated, this arrangement being, therefore, very suitable for gritty liquid likely to score the barrel.

If there are two or more buckets or pistons, each provided with elastic devices acting simultaneously to cause flow in the same direction, the buckets or pistons will share the work between them, the elastic devices being compressed and expanding together.

Tn-Fig. 12, however, is shown a pump having two buckets operated by cranks set at 180 to each other. Thus. when rod 7* is at the top of its stroke. rod 7" is at the bottom of its stroke. It will be seen that each bucket will operate practically independently of the other each giving an impulse every revolution of the cranks. Thus there are two impulses per revolution of the crankshaft at equal intervals.

At slow speeds and during starting up, this type of pump has the advantage that it operates like any other pump having two sets of valves, and if desired may be independent of the momentum of the moving column for drawing in fresh liquid. It will indeed function either way according to the speed of operation.

By introducing a third, fourth, or more buckets or their equivalent. it may be. arranged that the impulse exerted by one bucket may not have ceased before that from another begins. so that a continuous pressure is obtained.

Fig. 13 illustrates a modification especial- 1y adapted for one, two, three, four or more buckets.

At the lower end of tube 1 are valves 2, andthe said tube is adapted to slide over the external surface of the lower end 3 of pipe ,16 which corresponds with similar pipes 16 in otherfigures. e

It is assumed that where necessary suitable acking is provided to prevent or minimize eakage between pipe 3 and tube 1.

The side rods 7* have similar functions to rods-.7 in other figures and springs 4 and 14 act like similarly numbered springs in other figures.

Thus when rods 7 move upwards with increasing ,velocity, it being assumed that of Figs. 1 an 2 are carried out in Fig. 13,

and tube 1 acts as the bucket in Fi 1.

Another bucket in effect is readi y pro- 4 vided by fitting another tube 1 to slide outis ensured.

side tube 1 and having similar valves 2?, rods 7 and springs 4 and 14".

If the rods 7- and b are operated as in Fig. 12 by cranks at 180, similar effects regarding the frequency of impulses areobtamed.

Again, three tubes. telescoping over each other may be used 0 rated by three cranks at 120 and then- 1'. ere are three impulses per revolution, or four tubes operated by four cranks at 90 gives four impulses pe revolution, and so on.

The bottoms of the tubes containing the valves may be attached to the tubular sides elastically, say through the medium of inflated neumatic cushions as shown in Fig. 11, and by this means additional elasticity In general,'it is desirable to introduce the elastic devices, or part of them, as close to the liquid valves as possible.

In large pumps the seats of the valves themselves may be formed of inflated tubes.

The type of valve shown in Fig. 5 is naturall resilient and, therefore, very suitable for '5 pump.

A very simple system of employing multiple buckets or pistons is shown in Fig. 14.

A number of barrels, in this case 4, namely 3, 3", 3 and 3 are joined by bends. Each barrel has a bucket as at 1, 1", 1 and 1; rods 7, 7", 7 and 7 and the elastic devices are shown at 4, 14, 4 14, 4, 14 and 4, 14, but may'of coursebe in any suitable position. Buckets 1 and 1 are operated by a common crank 31 and connecting rod 44, slipper 32 working in slipper guide 33, and the slipper 32 carries projecting arms 45 and 45 which impart the impulses through elastic devices 4- and 4 in barrels -ama a---' respectively. It will be noted that valves 2 open upwards and valves 2 dqwnwa and. that 4 glyes an impulse upwards an 1 downwards.

Thus althoughthe two buckets are operated by a common crank the impulses are two er revolution as in the case of Fig. 12.

on another pair of barrels is used as at 3 and 3, the crank 31 operating them is preferably set at 90 to crank 31, so that the impulses occur between those governed b crank 31.

1f 6 arrels are used with 3 cranks, the latter would be preferably set at 120 to one another, giving 6 impulses per revolution at equal intervals. The ipe 16 may be extended to any desired ength for steadiness of working, but with suitable and suflicient elastic devices a much shorter length is reuired than in cases with fewer barrels. uction pipe 27 leading to the liquid to be pumped may have a foot valve or valves as before to facilitate priming.

The type of pump shown in Fig. 6 may also be amplified in this manner, as also ma a modification of the t pe in Fig. 13. 11 many cases it is advisa 1e to vary the diameter of barrel and lain pipe to reduce as much as possible sudden changes in velocity or to economize material as has been shown in Figs. 1, 2,3, 4, 6, 8 and 12.

Another arrangement is shown in Fi 15; which, although not suitable for m ti l0 pistons in series, has certain advantages no tosimplicity of construction. The ram 1 works in barrel 3. Crank 31 rotates and through connecting rod 44 reciprocates part 5 which can slide in the ram 1, springs 4 and 14 are held preferably under some initial tension between part 5 and the ends of the ram 1. As part 5 moves to the right to impart'inipulse to the liquid column in 16, spring 4 is compressed similarlyto springs 4 in previous figures and spring 14 prevents shock at the,end of a period of impulse. Between the impulses valves 2 open to allow of thepassage of fresh liquid to follow the moving colunm in 16.

During the impulse as the valves 2 are closed the liquid in pipe 27 must either come to rest, or if an elastic cushion is provided as at 46, compress this elastic cushion, but the motion of the liquid throughout the system is not continuous in the same sense as in'the previously described cases.

In certain cases instead of using inflated cushions as in Figs. 9 and 10, the required effect may be produced by using a piston workin 1n a cylinder so as to compress an air cus ion. To prevent leakage the pieton may be covered with liquid, the rate of leakage being less for liquid such as thick oil than for a gas. In either case the leakage can be made up by pumping in gas or liquld substitution for that which has leaked 'out.

-I am aware thata .sprin has been inserted between the cross-he of a lunger pump for liquids and the plunger, ut the u mp does not operate in the-manner herein. "defined, and the spring "herein claimed.

Having thus described the nature of the said invention and the best means I know of carrying the sameinto practical-efiect, Iclaim:-" "I 1 In a method or raising or forcing -'liquids which consists in moving by the power portion of the stroke of a. reciproeating-piston .a column'of liquid so that it acquires momentum sufiicient to keep the column in movement after the power por- 'tion'of the-stroke has ceased to act and so liquid is given sufiicient momentum to cause power stroke of the pump 1 the column to continue to move after the has ceased to act and so to draw in more quid in the direction of flow, and means positionedbetween the driving means and the piston adapted to permit the piston substantially to follow 'the movement of the liquid during the power portion ofa stroke independently of the motion of the parts of the driving means.

3. A pump including. a piston, a meansfor drivin the piston, whereby a column of liquid is given sufiicient momentum to cause the column to continue to move" after the power stroke. of the pump has ceased to act and so to draw in more liquid in the direction of' flow, and a resilient device interposed between the driving means and the piston adapted to permit the piston substantially to follow the movement of the liquid during the power portion of a stroke independently of the motion of the parts of the driving means.

4. A pump including a piston, a means for driving the piston, whereby a column of liquid is given sufficient momentum to cause the column to continue to move after the power stroke of the pump has ceased to act and so to draw in more li uid in the direction of flow, a resilient evice interposed has not the function i power portion of a stroke.

liquid during. the power portion of a stroke independently of the motion of the parts of the driving means, and an elastic buffer adapted to prevent shock at the end of the 5. A pump including a piston means including a. rotatmg "crank for driving the piston, whereby a column of liquid is given suflicient momentum to cause the column to continue to move after the power stroke of the pump has ceased to act and so to draw in more liquid in the direction of flow, and means interposed between the driving means and the piston for permitting the piston to of the motion of the parts of the driving means.

6; A pump including-a piston, means inc cludlng a'rotatlng crank for driving the driving means and the piston adapted to permit the piston'to follow the movement of the liquid during the power portion of a stroke independently of the motion of the parts of the drivin means- 7 f1. A pump including a piston, means comprising arotating crank for driving the piston, whereby a column of ii uid is given sufficient momentum to cause tie column to continue to move after the power stroke of the pump has ceased to actand so to draw in more liquid in the direction of flow, a resilient device interposed between the drivmg means and the part of the piston in contact with theliquid, said device being adapted topermit saidpart of the piston 'follow the'movement of the liquid during the power portion of a'stroke independently of the motion of the parts of the drivingmeans, and an elastic buflcr adapted to prevent shock at theend ofthe power portion.

of a stroke. I

In testimony whereof I have signed my name to this specification.

WILLIAM JOSEPH RUSDELL.

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