US1248743A - Apparatus for controlling hydraulic pumps. - Google Patents

Description

M. c. smsa. APPARATUS FOR CONTROLLING HYDRAUILIC PUMPS.

APPLICATION FILED MAY I9. 19M- Pmem edi 11m. 4,1917. 2 SHEETS-SHEET I.

WITNESSES M; C. STEESE. APPARATUS FOR CONTROLLING HYDRAUHC PUMPS.

AFPLICATLON FILED WW 9'. I914. n

Patented Dec. 4L, 191 f.

2 SHEETS-SHEET 2- MARCUS C. STEESE, OF YOUNGSTOWN, OHIO.

APPARATUS FOR CONTROLLING HYDRAULIC PUMPS.

Specification of Letters Patent.

Patented Dec. 4, ram.

Application filed May 19, 1914. Serial No. 839,550.

To all whom it may concern:

Be it known that I, MARCUS C. S'rnnsn, a resident of Youngstown, in the county of Mahoning and State of Ohio,have invented a new and useful Improvement in Apparatus for Controlling Hydraulic Pumps, of which the following is a specification.

This invention relates to apparatus for controlling hydraulic pumps and particularly duplex pumps. The object of the invention is to provide controlling apparatus which regulates the pump speed in exact accordance with variations in the demands upon it, which prevents racing of the pump and the sudden admission to the engine operating the same of a large supply of fluid pressure and thereby avoids liability of breakage or of overstraining the pump parts, and which is so arranged as to provide a reservoir of liquid, so that an increase in the demand upon the pump is supplied immediately, while the pump speeds up to take care of the demand.

The invention comprises the construction and arrangement of parts hereinafter described and claimed.

In the drawings, which represent one embodiment of the invention, Figure 1 is a view partly in side elevation andpartly in section of an embodiment of my invention, the position shown being that when-the pump is running at a speed intermediate its minimum and maximum speeds; Fig. 2 is an end elevation; Figs. 3 and I are detail views of certain connecting rods; Fig. 5 is a detail view showing a modification; Fig. 6 is a detail view showing a modified form of some of the parts; and Fig. 7 is a detail cross section on the line 77, Fig. 1.

Hydraulic pumps are commonlyv controlled by means of a balanced valve placed in the conduit which supplies fluid pressure, such as steam, air, or other substance under pressure, to the driving cylinders of the pump, this valve being operated by an accumulator which is connected to the main fluid line from the pump to the mill. The travel of this accumulator controls the amount of fluid pressure admitted to the driving cylinders of the pump and thus controls its speed and the amount of fluid forced by the pump to the millf Several types of apparatus have been used for controlling this valve. In one arrangement the accumulator operates two trips which are connected to the valve. In a second arrangement the accumulator is Experience has shown that the effect produced by the arrangements described upon the engine which operates the pump is detrimental to its action because fluid pressure is not supplied in direct proportion to the variation of the demands on the pump, and the engine and pump are therefore submitted to heavy and undue strains and stresses which are liable to result in breakage or at least in weakening the parts. If the pump is of the compound or triple expansion type or any type in which the driving pressure is not the same in all cylinders, it frequently happens that the pressure in all cylinders other than the high pressure cylinders becomes wholly depleted if the pump stands at rest for any appreciable length of time. Then, when an outlet from the main fluid line from the pump to the mill is opened up and a demand. thereby made upon the pump for fluid, the accumulator moves to supply this demand. In the first arrangement described the controlling valve is not opened until the accumulator reaches nearly the end of its stroke and then it opens suddenly to practically its full extent. In the second arrangement the valve is opened uniformly in direct proportion to the movement of the accumulator shell and tends to start the pump. This quick or uniform opening of the valve throws a large volume of fluid pressure into the high pressure cylinders and tends to start the pump at practically its maximum speed from rest or from a very low speed. After the pump has made one or two strokes, all cylinders are filled up and site direction from its former travel, its

barrel is again filled up to its maximum reservoir capacity and the fluid supply valve is closed, either suddenly with the trip arrangement described, or uniformly with the accumulator motion in the second arrangement described. The pump is quickly stopped, thereby producing the same rack and strain'of the parts as before, but in the reverse direction.

l/Vith this action, therefore, unless the mill or mills which are being supplied by the pump are continually calling for a large percentage oi thepump capacity the entire action of the control mechanism is to start and stop the pump under full load conditions and the pump is thereby strained 1 leakage only, the fluid is supplied to the engine at first at a very low rate, which gives the engine ample opportunity to fill all of its cylinders with the proper amountsof driving fluid and .to pick up speed gradually, and, as the controlling valve is further openedv up, a, gradually lncreasing amount ofdriving fluid is supplied to all .ofthe cylinders, to thereby speed the pump up. until it can fully take care of the entire demand. With this arrangement there is no liability of the engine racing when there is an extra heavy demand imposed upon any one cylinder or upon-the whole pump unit before it hasreached the proper working conditions to take care of the extra duty.

Also, for either small or great variations in the demand, the controlling apparatus reguzlates the fluid pressuresupply valve so that it does not open orclosein direct proportion to the demand variation, but to secure a variation in the speed of operation of the engine and .pump and in the output of the pump which is directly proportional to the demand variation.

In the arrangement shown in the drawings, the accumulator tank is of common construction and comprises a suitable vessel one. which may be loaded with water and is provided with an inner closed cylinder 2 slidable upon the upper end of a conduit 3 which is provided with a connection 3? to the main line supplied by the pump. It will be-vunderstood that when the pump is running or when the operating fluid pressure supply is turned into the pump and it is at rest, the head produced forces liquid up through the conduit 3 into the cylinder 2 and lifts the accumulator to a level depending upon the demand upon the pump. The conduit and tank are mounted on a suitable base i provided at one side with b 'ackels 5 in which is journaled a shaft (Shaving a double armed lever rigidly connected therewith. One arm of said lever comprises one or a pl rality of horizontal members 7 carrying counterweights 8 adjustable thereon, while the other arm of the lever is a member f) riveted or otherwise secured to a yoke 10 on the shaft (5 and which arm extends up along the side of the accumulator tank. The arm 9 is shown an an I-beam Whose main body portion is straight and inclined slightly away from the accumulator tank and whose upper end is inclined more sharply away from said tank, the two inclined portions of said arm being joined at the bend 11. Said arm coiiperates with the accumulator tank and is oscillated about the pivot 6 as the tank rises and falls by a grooved roller 12 on the tank, against which the lever is held by the counterweights 8. Arm 9 is inclined away from the tank so that asthe tank drops it forces the lever to turn on its pivot and swing farther away from the tank. Instead of the arrangement just described, the tank may be provided with apin 13 traveling up and down in a longitudinal slot 1% in the arm 9, as in Fig. 6, and thereby moving it positively in both directions, in which case the counterweights may be dispensed with. Either arrangement described prevent rotation of the tank on its vertical axi and does away with the necessity of special tank guides.

15 represents the casing of the valve for controlling the liuid pressure supply to the engine for operating the pump. Said valve may be of any suitable type and is shown as a balanced valve member 16 cooperating with two valve seats 17 and having a stem 18 extending to the outside of the valve casing and connected to a lever arm 19 provided with the adjustable counterweight 20 and pivoted to a fixed part of the casing.

Arm 9 and lever 19 are connected by suitable mechanism arranged to produce a variable movement of the valve for uniformvariations in movement of the accumulator tank in the manner before described. The

connections shown comprise a double armed lever pivotally mounted in a bracket 26 depending from the casing 15 of the valve.

One arm of said lever, such as the arm 25, is connected to the vertical arm 9-, such as by the rigid link. 27 preferably provided lever is in the form of a large segment connected to the lever 19 by a rigid link 32 which may be provided with a turnbuckle for adjusting its length in the same manner as the link 27 and is shown as comprising two members telescopically connected as at 32 and fastened together by a cross pin 33 which may be placed in the proper ones of anumber of apertures in said members. The pivot pin 40 connecting the lever arm 31 and link 32 may also be placed in any one of a number of apertures 41 and 4E1 in said lever arm and link 32 inv order to adjust the link with reference to the lever arm as will be readily understood.

The apparatus described operates as follows Tn Fig. 1 of the drawings the parts are shown with the accumulator tank in a position intermediate its two extremes of movement, that is, in a position in which some demand is being made on'the line and the pump is supplying saiddemand. The ac cumulator tank stands in a position with its roller at the point A and at a level depending upon the head and the demand on the line. Arm 9 is held in contact with the roller 12 and the valve 16 is partly opened and supplies the proper amount of fluid pressure to the engine to cause the pump to just keep pace withthe demand upon it. If the demand upon the main line is reduced the pressure therein increases and liquid flows up into the accumulator tank through 3 and elevates the same to a position in which the roller is at approximately the point marked B, that is, just a little below the bend 11 in arm 9. If an abnormal demand is made upon the line such as by a break therein, the accumulator tank drops to a position in which the roller stands at the position marked C, with the accumulator tank close to the bumpers 45.

Let us assume a condition in which the roller 12 occupies the position indicated at B, in which the pump is barely moving, and only supplies the leakage from the main line, all outlets from which are closed. When an outlet from the main line is opened the first action is for the accumulator tank to drop, thereby causing the roller to move down along the inclined arm 9, and swing the same away from the accumulator tank. In its upper position the roller is at a con siderable distance from the pivot 6 so that a given amount of downward movement of the roller produces a comparatively small movement of the arm 9. As the tank moves downwardly however, the roller approaches closer to the pivot 6 and the same given uniform movement of the tank produces a greater effect upon the lever arm as it approaches said pivot.

The movement to the left of arm 9 is communicateddirectly to the lever arm 25 by 25, practically the entire motion of the arm 9 in a horizontal direction is transmitted to the lever arm 25, which produces a corresponding movement of the pivot 40 connecting the lever arm 31 and link 32 in the con trary direction or to the right in Fig. 1. The pivot 4:0 also travels in a circular path, so that its motion has two components, a horizontal component and a vertical component, of which only the vertical component is transmitted by the link 32 to the lever 19 which operates the valve. WVhen the pivot 40 is in its lowest position a given amount of movement to the right has only a small vertical component but as said pivot moves farther and farther to the right the vertical component increases and the horizontal component decreases, so that the efl'ect upon the valve produced by uniform movement of the pivot 40 increases as the valve opens.

The increasing effect of the accumulator movement on the fluid pressure valve is due to the fact that it is not the value of the angular movement of the parts which is transmitted to said valve, but only the value of the sine of the angular movement. This peculiar effect is produced by two different parts of the mechanism, first by the arm 9 and secondly by the pivot 40 at the end of the lever arm 31. The net result is that when a demand is made upon the pump by opening an outlet from the line, the valve at first is opened very slowly and supplies fluid pressure to the engine side of the pump at a slow rate which enables it to start gradually without sudden impulse and without shock and racking movement, and which allows the cylinders of the engine tofill up with fluid pressure before the full supply is turned on. In the meantime the accumulator tank itself has been supplying the demand upon the line and as it drops lower and lower gradually produces an increased opening efl'ect upon the valve and admits an increasing supply of fluid pressure to the engine. By the time the valve is opened sufliciently to admit a full supply of fluid pressure the engine cylinders have filled up and the pump is running at a fair speed, so that it picks up to full speed without straining its parts. In practice the controlling apparatus is very sensitive and adjusts the fluid supply so that the engine speed gradually increases to a point where the pump fully supplies the demand upon it, at which point the accumulator tank becomes stationary, as at a point where the rolleris at the position marked A in the drawings.

If new the demand on the pump is reduced as by closing one or more of the outlets from the line, the first effect is for the liquid to rush up into the barrel of the accumulator tank and lift said tank, causing the roller 12 to travel up along the arm 9.

Arm9 is held in contact with said roller by the counterweight 8 and therefore moves to the right in Fig. 1, oscillating the lever 25-31 and moving the valve in the closing duced by a given upward movement of the tank is comparatively great, the valve movement, for a given upward movement of the tank, gradually decreasing as the tank moves upwardly.

In operation, the accumulator tank rises and falls as the demand upon the pump decreases or increases, but the varying. effect produced on the valve by uniform move ment of the accumulator tank is such that the regulating apparatus does not hunt, but has a very steady movement which at times is almost imperceptible although it takes place constantly.

If all the outlets from the main line are closed the accumulator tank should rise to the position in which the valve is fully closed, which position is the one when the roller is at the point marked B, that is, just below the bend 11 in the arm 9. If the valve is choked with a small particle of dirt or foreign matter so that it does not fully close the pump keeps on operating and forces the liquid up. into'the accumulator tank which rises to an abnormally. high position, that is, above the bend 11. The upper sharply inclined end portion of the arm 9- then permits said arm to be moved over forcibly and sharply to the right in Fig. 1 by the counter-weight 8, which is usually effective to fully close the valve under all circumstances commonly encountered in practice. This arrangement stops the pump under unusual conditions and prevents it from lifting the accumulator tank to an unsafe position.

Fig. 5 shows a modification in which the arm 9 is so arranged as to close the valve in case the accumulator tank falls materially below its downward limit of movement. In

lowest limit of travel or to a position in which theroller 12 is opposite the bend 42,

whereupon the arm 9 is forced fully over to the right in Fig. 5 by the coLmt'er-weight 8, so that the roller 12 enters the bend 42. This entirely closes the fluid pressure supply valve and stops theengine, thereby preprising venting the engine and pump from racing and possibly destroying or injuring themselves. Arm 9 may if desired be provided with a movable or removable cover member 43, shown in dotted lines, which can be placed over the bend 42 to cut out this safety feature.

The apparatus described is simple and forms a perfect regulating device for fluid pressure pumps. It controls the pump in such manner that it takes care of all variations in load imposed thereupon, and supplies fluid pressure to the engine for operating the pump in quantities which are so regulated as to change the pump speed in direct proportion to the variation in demand. At the same time the apparatus is so arranged as to avoid hunting, such as occurs in most governors, and thereby is verysteady and even in operation.

What I claim is:

1. Apparatus for controlling the motive fluid for operating hydraulic pumps, commeans responsive to variations in the pressure produced by the pump, a valve for controlling the motive fluid for operating said pump, and mechanism operated by the pressure responsive means for actuating the valve, said mechanism being arranged so that the rate of movement of the valve varies in uniformity relative to the rate of movement of the pressure responsive means.

2. Apparatus for controlling the motive fluid for operating hydraulic pumps, comprising meansresponsive to variations in the pressure produced by the pump, a valve for controlling the motive fluid for operating said pump, and mechanism operated by the pressure responsive means for actuating the Valve, said mechanism being arranged so that when the pressure responsive means moves under variations in pressure the valve is actuated at a varying rate.

3. Apparatus for controlling the motive fluid for operating hydraulic pumps, comprising means responsive to variations in the pressure produced by the pump, a valve for controlling the motive fluid for operating said pump, and mechanism operated by the pressure responsive means for actuating the valve, said mechanism being arranged so that when the pressure responsive device moves uniformly in one direction due to decrease in pressure the valve is first actuated slowly and then more rapidly.

4. A pump governor comprising means responsive to the pressure produced by the pump, a valve for controlling the motive fluid for operating the pump, and mechanism actuated by the pressure responsive means for operating the valve, said mechanism being arranged so that the valve is actuated at a varying rate of speed relative to the rate of speed of the pressure responsive sive means for operating the valve, said mechanism being arranged so that as the pressure responsive means moves at a uniform rate in response to decreases in pres-.

sure the valve is first opened slowly and then more rapidly, said mechanism being also arranged so that when the pressure responsive means is moved to the limits of its travel by abnormal increases or decreases in pressure the valve is automatically closed.

6. A pump governor, comprising means responsive to the pressure produced by the pump, a valve for controlling the motive fluid for actuating the pump, and mechanism actuated by the pressure responsive means for operating the valve, said mechanism being arranged so that as the pressure responsive means moves in response to decreases in pressure the valve is first opened slowly and then more rapidly and as the pressure responsive means moves under increases of pressure the valve is first closed rapidly and then more slowly.

7. A pump governor, comprising an accumulator responsive to the pressure produced by the pump, a valve for controlling the motive fluid for actuating the pump, a pivoted cam bar normally biased into engagement with a camming surface on the accumulator, and a series of levers connecting the cam bar and the valve arranged so that as the accumulator moves uniformly the valve is actuated at a varying rate.

8. A pump governor, comprising an accumulator responsive to the pressure produced by the pump, a valve for controlling the motive fluid for actuating the pump, a pivoted cam bar normally biased into engagement with a camming surface on the accumulator, and a series of levers connecting the cam bar and the valve arranged so that as the accumulator moves uniformly in response to decreases in pressure the valve is first actuated slowly and then more rapidly.

9. A pump governor, comprising an accumulator responsive to variations in the pressure produced by the pump, a valve for controlling the motive fluid for actuating the pump, a pivoted cam bar normally biased into engagement with the cam surface on the accumulator, and a series of levers connecting the cam bar with the valve whereby movements vof the accumulator are transmitted to the valve, said cam bar being shaped so that when the accumulator reaches the limits of its movement in either direction due to abnormal increases or decreases in pressure the box, is automatically operated to close the valve.

10. Apparatus for controlling the fluid supply for operating hydraulic pumps, comprising an accumulator tank supplied by the pump and arranged to rise and fall with variations in demand upon the pump, a valve in the fluid supply for operating the pump, a lever having an inclined portion and arranged to be controlled by said ac cumulator tank, a pivoted double armed lever, and connections between said levers and between said double armed lever and valve for controlling the latter.

11. Apparatus for controlling the fluid supply for operating hydraulic pumps, comprising an accumulator tank supplied by the pump and arranged to rise and fall with variations in the fluid supply for operating the pump, a vertical pivoted lever at one side of said tank and arranged to move about its pivot in accordance with the rise and fall of saidtank, a pivoted lever operated by said vertical lever, and connections between said second named lever and valve for operating the latter.

In testimony whereof, I have hereunto set my hand.

MARCUS G. STEESE.

Witnesses ELBERT L. HYDE, WmLmM B. WHARTON.

topics or this patent may be obtained for five cents each, by addressing the Gommissioner or Watenta. Washington, W. e.

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