US2590014A

US2590014A - Piston and independently operated

Info

Publication number: US2590014A
Authority: US
Publication date: 1952-03-18
Anticipated expiration: 1969-03-18

Description

March 1952 A. IVANOFF ETAL PISTON AND INDEPENDENTLY OPERATED DISTRIBUTING VALVE FOR RECIPROCATING PISTON ENGINES Filed March 51, 1945 5 Sheets-Sheet 2 March 18, 1952- WANOFF r 2,590,014

PISTON AND INDEPENDENTLY OPERATED DISTRIBUTING VALVE FOR RECIPROCATING PISTON ENGINES Filed March 31, 1945 3 Sheets-Sheet 3 grave/77521! Patented Mar. 18, 1952 PISTON AND INDEPENDENTLY OPERATED DISTRIBUTING VALVE FOR RECIPROCAT- ING PISTON ENGINES Alexander Ivanoff and Giles Philip Eliot Howard,

Luton, England Application March 31, 1945, Serial No. 585,912 In Great Britain March 21, 1944 Section 1, Public Law 690, August 8, 1946 Patent expires March 21, 1964 14 Claims. 1

This invention relates to prime movers comprising reciprocating pistons operated by fluid pressure. The invention is particularly applicable to those arrangements in which a reciprocating piston operated by fluid pressure (say steam) is direct coupled to the plunger of a reciprocating pump, so that the piston and plunger reciprocates as one piece.

The invention is, however, applicable to all prime movers comprising reciprocating pistons operated by fluid pressure, Whether the piston operates through a crank shaft and fly wheel or not, and whether it drives the plunger of a re ciprocating pump or some other driven device.

The object of the invention is the provision of improved means for controlling the movement of the piston throughout the cycle so as to give it a desired characteristic. The invention, in its broadest aspect, consists in the arrangement that the valve means which control the flow of the pressure fluid to the cylinder are controlled jointly in accordance with the movements both of the piston and of another independently driven cyclically operating device.

In order that the invention may be the more clearly understood certain embodiments thereof ,will now be described, reference being made to the accompanying drawings, wherein:

Figure 1 is a sectional side elevation of an arrangement in accordance with the invention in which a reciprocating piston driven by steam is direct coupled to the plunger of a reciprocating pump, the parts being .at the position of rest at the right hand end of the stroke.

Figure 2 is a section on line II-II of Figure 1.

Figure 2A is a sectional view generally corresponding to Figure 2, but showing a modified arrangement thereof in the form of a duplex set.

Figure 3 is an outside view of the left hand portion of the arrangement of Figure 1, the position being that at which the stroke to the left has been started.

Figure 4 is a similar view of the same, the parts being at the position of rest at the left hand end of the stroke.

Figure 5 is a similar view of the same, the position being that at which the stroke to the right has been started.

Figure 6 is a side elevation of a similar arrangement, but having a somewhat different form of control gear, the position being that at which the stroke to the right is about half completed.

Figure 7 is a section on line VII-VII of Figure 6. I

Referring first to all the figures the same illustrate a steam cylinder I and a pump cylinder 2 arranged coaxially, the piston 3 of the steam cylinder I being rigidly coupled, by means of a piston rod 4, to the pump bucket or plunger 5 so that said piston and plunger reciprocate as one piece. The pump is of the common type In which, when the plunger 5 moves from left to right, liquid is sucked through the inlet 6, into a space I, and from there past a valve 8 (which lifts) into a space 9 and thence to the left hand end of the cylinder. Simultaneously liquid is forced from the right hand end of the cylinder into a space I0 and thence past a valve I I (which lifts) into a space I2 and. out at the outlet, I3. In like manner, when the plunger 5 moves from right to left liquid is sucked through inlet 6 into space I and past a valve I4 (which lifts) into the space I0 and thence to the right hand end of the cylinder. Simultaneously liquid is forced from the left hand end of the cylinder into the space 9 and past a valve I5 into the space I2 and out at the outlet I3.

Steam for the steam cylinder I is supplied by way of a supply pipe I6 and flows freely to the two ends of a valve chamber I! in which reciprocates a piston valve I8. The valve chamber I'I communicates by way of conduits I9 and 20 and the two ends of the cylinder I and said chamber I! also communicates at its centre, by way of a conduit 2I, with an exhaust pipe 22. As will be readily seen from the drawing the piston valve I8 has two

valve pistons

23 and 24 which, in the mid position of said valve, close said conduits I9 and 29. When said valve I8 moves to the right from said mid position, the valve piston 23 uncovers the conduit I9 to admit live steam to the left hand end of the cylinder I and the valve piston '24 uncovers the conduit 20 to connect the right hand end of the cylinder I to exhaust. The piston 3 accordingly moves from left to right. Conversely when said valve I8 moves to the left from mid position, the valve piston 24 uncovers the conduit 20 to admit live steam to the right hand end of the cylinder, and the'valve piston .23 uncovers to conduit I9 to connect the left hand end of the cylinder' to exhaust. The piston 3 accordingly moves from right to left.

In all the figures, control is effected through the medium of a cam 25 which is continuously rotated by means of an independent prime mover 26. The valve I8 is coupled to said cam 25 in such a way that rotation of said cam tends to reciprocate said valve continuously first in one direction. and then in the other, and, at the same a substantially constant length of stroke and hence displacement, whether liquid, gas or vapour is being pumped, and to give the piston a reduced velocity and/or acceleration at the ends of its stroke so as to enable the pump valves to operate silently even under high speeds of operation of the prime mover.

It may be pointed out that, owing to the angularity of the link mechanism the cam will need to be somewhat asymmetrical to produce symmetrical movement of the piston.

It will be clear that there are many possible mechanical arrangements capable of correlating the cam, piston valve and piston in the required way. Figures 6 and 7 illustrate one alternative mechanism for this purpose. In'this mechanism the piston rod 4 has a cross head 21 carrying a rocking pin 28 as before, and, as before, a cross head lever 29 passes slidably through a diametrical hole in the head of the rocking pin. The cross head lever 29 however, unlike the preceding arrangement, is pivoted about a fixed axis 43 near to its end remote from the cross head, and, at its end remote from the cross head, carries the bearing 44 for the cam shaft. As before, the cam is continuously rotated, and, in the present case, the tendency of the piston 3 to return the piston valve 18 to the centre position is by virtue of the bodily movement of the cam, in response to the movement of said piston causing the cross head lever 29 to rock about the pivot axis 43.

Thus, referring to Figure 6, assuming the cam 25 to be rotating in a clockwise direction, said cam, by virtue of its rotation, will be tending to permit movement of the piston valve l8 to the right, and thus the conduits l9 and will be uncovered in such a direction as to cause the piston 3 to be moving to the right. The cross head 21 will accordingly be moving to the right ciprocates in a manner determined by the shape of the cam.

In order for the motor 25 to rotate the cam, while the latter is making its bodily to and fro movement as described, the cam shaft has a gear wheel 45 mounted on it, which is in train,

through the medium of a gear wheel 46 whose bearing is also carried by the lever 29 as shown, with a gear wheel 41 which is coaxial with the aforesaid axis 43. A worm wheel 4! is mounted on the shaft of said gear wheel 41, said worm wheel being driven by .a worm coupled to the motor 26. It will thus be seen that, without interruption of the continuity of the transmission from the motor 26 to the cam 25, through the elements 40, 4|, 41, 4B, 45, the cam together with the gear wheels 45 and 46 are capable of being rocked about the axis 43, the gear wheel 46 simply moving to and fro around an arc of the gear wheel 41. This movement will however obviously produce a cyclical variation in the speed of rotation of the cam which must be taken account of in designing the cam contour. It may be mentioned that the gear wheel 46 is interposed between the

gear wheels

45 and 41 merely for con- ;venience, of design. The gear wheel 45 mightbracket 38 on a base 39 as before.

equally well mesh direct with the gear wheel 41. The mechanism illustrated in Figures 6' and 7 enables the cam and gears to be totally enclosed in a dust and oil tight casing 48. Thus thetwo parts of the lever 29 on opposite sides of the axis 43 are off set from each other being joined by a shaft 49 coaxial with said axis 43; The oil tight bearing 50 for this shaft is sealed in a Wall of said casing 48, and thus the upper portion of the lever 29 is insidethe casing whereas the lower portion is outside the casing. Thus the cam and gears are all inside the casing as stated. The shaft of the piston valve l8 passes through an oil tight bush in the wall of the casing 48 as shown,

and the drive from the motor to the worm 40 also pass in sealed relation through a wall of said casing.

As will be seen the motor 26 is mounted on a As shown said base 39 supports the bearing 50 and the bearing of the gear wheel 41 and worm wheel 4|, and also supports the casing 48.

It will be appreciated that the invention is applicable to other arrangements than enginepump combinations such as described. For example the piston could operate through a crank, crank shaft and fly wheel, and in such case, the arrangement of control as described above results in the automatic adjustment of the cut-off to the load, and in the speed being held exactly at the desired value regardless of variations in steam pressure or load, and this may be an advantage for certain applications.

What we claim and desire to secure by Letters Patent is:

1. A prime mover comprising a cylinder, a piston reciprocatable in said cylinder, valve means controlling the admission and exhaust of pressure fluid toand from said cylinder for reciprocating said piston, a cyclically operating cam device, means independent of said prime mover for driving said cam device and means operable on said valve means for moving said valve means in response jointly to the operation of said cam device and to the movements of said piston so that said piston is reciprocated in a controlled manner with a characteristic depending on the characteristic of said cam device.

2. A prime mover comprising a cylinder, a piston reciprocatable in said cylinder, valve means displaceable to opposite sides of a neutral position for controlling the admission and exhaust of pressure fluid to and from said cylinder for reciprocating said piston in opposite directions, a cyclically operating cam device, means independent of said prime mover for driving said cam device, and means responsive to said cam device for reciprocating said valve means, and also responsive to movement of said piston upon displacement of said valve means on either side of the neutral position, to restore said valve means to the neutral position, so that said piston is reciprocated in a controlled manner with a characteristic depending on the characteristic of said cam device.

3. A prime mover comprising a cylinder, a piston reciprocatable in said cylinder, valve means controlling the admission and exhaust of pressure fluid to and from said cylinder for reciprocating said piston, displacement of saidvalve means on opposite sides of a neutral position being adapted respectively to effect movement of said piston in opposite directions, a cyclically operating cam device, means independent of said prime mover for. driving said cam device, afloating lever, means whereby said floating lever is actuated by said cam device, means whereby said floating lever is actuated .by the reciprocating piston, and means whereby said valve means are actuated by said floating lever, whereby operation of said cam device tends to reciprocate said valve means, and whereby movement of said piston in response to displacement of said valve means on either side of the neutral position tends to restore said valve means to the neutral position, so that said piston is reciprocated in a controlled manner with a characteristic depending .on the characteristic of said cam device.

4. A prime mover comprising :a cylinder, a piston reciprocatable in said cylinder, valve means controlling the admission and exhaust of pressure fluid to and from said cylinder for reciprocating said piston, displacement of said valve means on opposite sides of a neutral position being .adaptedrespectively to effect movement of said piston in opposite directions, a rotatable cam, means independent of said prime mover for rotating said cam, a floating lever, a roller carried by said lever and bearing against the cam surface of said cam, a piston rod for said piston, a cross head mounted on said piston rod, a rocking pin carried by said cross head, said floating lever passing slidably through a hole in .said rocking pin, and means coupling said floatton reciprocatable .in said cylinder, valve means controlling the admission and exhaust of pressure fluid to and from said cylinder for reciprocating said piston, displacement of said valve means on opposite sides of a neutral position being adapted respectively to effect movement of said piston in opposite directions, a rotatable cam, means independent of said prime mover for rotating said cam, a floating lever, a roller carried by said lever and bearing against the cam surface of said cam, a piston rod for said piston, a cross head mounted on said piston rod, :a rocking pin carried by said cross head, said floating lever passing slidably through a hole in said rocking pin, and a rocking lever coupling said floating lever to said valve means, whereby rotation of said cam tends to reciprocate said valve means, and whereby movement of said piston in response to displacement of said valve means on either side of a neutral position tends to restore said Valve means to the neutral position so that said piston is reciprocated in a controlled manner with a characteristic depending on the characteristic of said cam.

6. A prime mover comprising a cylinder, apiston reciprocatable in said cylinder, valve means controlling the admission and exhaust of pressure fluid to and from said cylinder for reciprocating said piston, displacement of said valve means on opposite sides of a neutral position being adapted respectively to effect movement of said piston in opposite directions, a cyclically operating cam device, means independent of:said prime mover for driving said cam device with a predetermined valve displacing and timing characteristic, means responsive to cyclical noperation of said cam device for reciprocating :said valve means, and means operable iupnn movement of said piston in response to displacement of said valve means on either side of the :neutral position for effecting bodily movement of said cam device in the direction to restore said valve means to the neutral position, the cyclical operation of the cam device and the bodily dis placement of the cam device as aforesaid causing controlled reciprocation of said piston with a characteristic determined by the characteristic of said cam device.

7. A prime mover comprising a cylinder, a piston reciprocatable in said cylinder, valve means controlling the admission and exhaust of pressure fluid to and from said cylinder for .reciprocating said piston, displacement of said valve said piston in opposite directions, a cyclically operating cam device, means independent of said prime mover for driving said cam device with a predetermined valve displacing and timing characteristic, means responsive to cyclical operation of said cam device for reciprocating said valve means, a lever carrying said cam device, said lever having a fixed pivotal axis, means coupling said lever to said piston and operable upon movement of said piston in response to displacement of said valve means on either side of the neutral position for rocking said lever and for effecting bodily movement of said cam device in the direction to restore said valve means to the neutral position, the cyclical operation of the cam device and the bodily displacement of the cam device as aforesaid causing controlled reciprocation of said piston with a characteristic determined by the characteristic of said oam device.

8; A prime mover comprising a cylinder, a 'p'iston reciprocatable in said cylinder, valve means controlling the admission and exhaust of pressure fluid to and from said cylinder for reciprocating said piston, displacement of said valve means on opposite sides of a neutral position being adapted respectively to effect movement-"of said piston in opposite directions, a cyclically operating cam device, means independent of said prime mover for driving .said cam device displacement of said valve means on either :side

of the neutral position for rocking said :lever and for effecting bodily movement of said :cam device in the direction to restore :said "valve means to the neutral position, the cyclical 'operation of the cam device and the bodily displacement of the cam device as aforesaid causing controlled reciprocation of said piston with a characteristic determinedby the characteristic of said cam device, said driving means for the cam device including a transmission train comprising a gear wheel concentric with the axis of said lever, and gear means carried by said lever and coupling said gear wheel to said cam device.

9. A prime mover comprising a cylinder, a piston reciprocatable in said cylinder, valve means controlling the admission and exhaust of pressurefluid :to and from said cylinder for reciproeating said piston, displacement of said valve means on opposite sides of a neutral position being adapted respectively to effect movement of said piston in opposite directions, a cyclically operating cam device, means independent of said prime mover for driving said cam device with a predetermined valve displacing and timing characteristic, means responsive to cyclical operation of said cam device for reciprocating said valve means, a lever carrying said cam device, said lever having a fixed pivotal axis, means coupling said lever to said piston and operable upon movement of said piston in response to displacement of said valve means on either side of the neutral position for rocking said lever and for effecting bodily movement of said cam device in the direction to restore said valve means to the neutral position, the cyclical operation of the cam device and the bodily displacement of the cam device as aforesaid causing controlled reciprocation of said piston with a characteristic determined by the characteristic of said cam device, said driving means for the cam device including a transmission train comprising a gear wheel concentric with the axis of said lever, and gear means carried by said lever and coupling said gear wheel to said cam device, said lever comprising a shaft coaxial with said fixed pivotal axis and two lever portions on each side of said axis spaced from each other along said shaft, a casing for said cam device, said gear wheel and said gear means, and a bearing for said shaft in a wall of said casing, whereby one of said shaft portions is outside said casing, the means coupling said lever to said piston being connected to one of the two lever portions aforesaid.

10. In combination, a plurality of prime mov ers, each of said prime movers comprising a cylinder, a piston reciprocatable in said cylinder, movable valve means controlling the admission and exhaust of pressure fluid to and from said cylinder for reciprocating said piston, a cyclically operating cam device, means independent of said prime mover for driving said cam device with a predetermined valve displacing and timing characteristic, means for moving said valve means in response jointly to the operation of said cam device and to the movements of said piston and with controlling effect upon the reciprocation of said piston according to the characteristics of said cam device, and means coupling the cam devices of said prime movers so that they operate in unison.

11. A combination as claimed in claim 10, wherein the sum of the speeds of the pistons of said prime movers responsive to the controlling effect of the cam devices is always substantially the same.

12. In combination, a plurality of prime movers, each of said prime movers comprising a cylinder, a piston reciprocatable in said cylinder, movable valve means controlling the admission and exhaust of pressure fluid to and from said cylinder for reciprocating said piston, a cyclically operating control device, means independent of said prime mover for cyclically driving said control device with a predetermined valve displacing and timing characteristic, means for moving said valve means in response jointly to the cyclical operation of said control device and to the movement of said piston and with controlling effect upon the reciprocation of said piston according to the characteristic of said control device, and means coupling the control devices of said prime movers so that they operate in unison, the sum of the speeds of the pistons of said prime movers responsive to the controlling effect of the control devices being always substantially the same.

13. A combination as claimed in claim 10, wherein there are two prime movers and the two pistons move ninety degrees out of phase with each other and the instantaneous speed of each when plotted against time conforms substantially to a sine squared law in response to the controlling effect of the cam devices.

14. A combination as claimed in claim 12, wherein there are two prime movers and the two pistons move ninety degrees out of phase with each other and the instantaneous speed of each when plotted against time conforms substantially to a sine squared law in response to the controlling effect of the control devices.

ALEXANDER IVANOFF. GILES PHILIP ELIOT HOWARD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 448,356 Miller Mar. 17, 1891 1,754,743 Diserens Apr. 15, 1930 1,772,121 Volz Aug 5, 1930 2,124,788 Leman July 26, 1938 FOREIGN PATENTS Number Country Date 2,086 Great Britain of 1885 B- KENNEDY March I, 1952 GLOVE Filed Aug. 24, 1949 IN VE N TOR. Ber! Ken rzc zlg BY W, adyegww ATTOR N EYS'