US2382027A - Power transmission - Google Patents

Description

Aug. 14, 1945. I E. L. ROSE 2,382,027

POWER TRANSMISSION Original Filed July 5, 195a 4 sheets-sheer 1 FIG. I

IINVENTOR -EDWIN L- ROSE v I v BY% I ATTORNEY Aug. 1 4, 1945. E. LHROSE 2,382,027

POWER TRANSMIS S ION Original Filed July 5, 1938 4 Sheets-Sheet 2 I N VEN TOR Aug. 14, 1945. E; ROSE 2,382,027

POWER TRANSMISSION 7 Original Filed Juiy'5, 1958 4'SheetsSheet 3 4 v I FIG. 3

ISO

0 304 328 we I 11 II 184- Q I ii 188 1h ao.--- I -\ss INVENTOR EDWIN L. ROSE -BY A JKVM ATTORNEY Patented Aug. 14, 1945 POWER TRANSMISSION Edwin L. Rose, Woodbury, Conn.

Original application July 5, 1938, Serial No.

217,395, now Patent No. 2,265,314, dated Decemher 9, 1941. Divided and this application April 25, 1941, Serial No. 390,237

3 Claims.

This invention relates to power transmissions and particularly to transmissions of the hydraulic type comprising a fluid pump and fluid motor either or both of which may be provided with mechanism for varying its displacement in order to vary the speed ratio between the prime mover which operates the pump and the load device which the motor operates. This application is a division of my copending application Serial No. 217,395, filed July '5, 1938, now Patent No. 2,265,314, which in turn is a division of my copending application, Serial No.- 90,'785, filed July 15, 1936, for Power transmission, now Patent No. 2,168,655. The invention is illustrated as adapted for use in a well drilling rig of the well-known type in which a string of drill stem is caused to revolve by a rotary drilling head while a portion of the weight of the string rests upon the earth formation at the bottom of the hole being drilled, the remainder being suspended on a block and falls mounted in a drilling derrick'and connected to a draw-works drum.

It is desirable in such drilling operations to maintain at a constant value that portion of the weight of drill string which rests upon the earth formation at the bottom of the hole and to be able to readily adjust such weight to different values as different formations are encountered. Various automatic control devices have been proposed for regulating the weight on the drill stem, many of which have been unsatisfactory, due to lack of sensitivity in their regulation. Some forms of automatic regulation utilize mechanism which isresponsive to variations in tension in either the live or the dead end of the cable, which supports the drill string through the block and falls. Such devices may not be made sensitive to the degree required since the friction of the sheaves introduces a damping effect which in some instances may be as high as 25% of the suspended weight. Such a device therefore can respond only to changes in suspended weight which are greater in magnitude than the frictional damping effect between the drill string stem and the weight sensitive device.

In earth boring operations of this general class it is necessary from time to time as the work progresses to retract the drill stem from the hole for the purpose of replacing the cutting bit at the lower end of the drill stem. In so doing it is necessary to stop the rotational movement of the drill stem and hoist the stem a suitable distance to near the top of the derrick, this distance usually being 90 feet, and to grip the stem at the rotary table and remove the section of the drill 66 only on the first hoist at a given ratio and that stem projecting above the table. The hoisting apparatus is then lowered and connected to the remaining portion of the stem projecting from the rotary table, and hoisted another feet and the operation is repeated until the entire string is removed from the hole. After necessary repairs to the bitare made, by reversing this proc- 'ess the bit may be again brought to working posi tion at the bottom of the hole. I

In many drilling operations of this nature it is of prime importance that the hole be cut down to its intended depth in the least possible total lapsedtime. Inasmuch as normal drilling operations are suspended while the drill string is being retracted and replaced for repair purposes, it is essential to keep the time consumed for this purpose to a minimum and it is customary to provide prime movers of several times the power output required for drilling operations so that the string may be retracted at a maximum speed and lost time reduced to a minimum. It will be seen that in retracting the string the weight of the string and the load to be lifted is progressively reduced as each section of drill stem is detached from the sections below it so that at each hoist of 90 feet the load to be hoisted is reduced by the weight of one 90-foot section of drill stem.

For a given maximum horsepower of the prime mover and a given weight of drill string there is only one speed ratio between the prime mover and the draw-works drum whichwill permit the string to be retracted at a speed which utilizes the full power of the prime mover. It is obvispeed ratio for a considerable number of consecu-' tive hoists of the drill stem before the drill stem weight is reduced sufiiciently to enable the operator to shift to the next higher ratio. It will be seen that with this method of operation the speed of hoisting is the same for several consecutive hoists of the drill stem and inasmuch as the weight of the stem is reduced at each hoist, the full power ofthe prime mover can be utilized 2 aseaoav thereafter the power load on the prime mover progressively decreases.

It is an object of the present invention to provide a power transmission incorporating an automatic feed control for maintaining constant weight on the bit at the bottom of the hole, which is responsive directly to the suspended weight and which operates with a high degree' of sensitivity to small changes in the suspended weight.

A further object is to provide a power transmission suitable for use as a draw-works drive for a well drilling rig whereby the ratio of power transmission between the prime mover and the connection which is, in the present invention,

suitable swivelling connection at 96 is provided for permitting circulation of themud laden cutting draw-works drum may be adjusted to the valuenecessary to utilize the full power output of the prime mover at each hoist of the drill stem.

A further object is to provide a power transmission of such character wherein an operatorcontrolled member may be moved to cause the draw-works drum to rotate in hoisting direction and wherein automatic means beyond the control of the operator acts to select the proper ratio of power transmission necessary to utilize the full power output of the prime mover for any given weight of drill stem.

It is also an object to provide a power transmission for a well drilling apparatus incorporating an automatic weight sensitive feed control for drilling, together with an automatic constant horsepower control for hoisting, wherein readily operable controls of a simple and reliable nature are provided for shifting operation of the apparatus between drilling and hoisting and viceversa.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to theaccompanying drawings wherein a preferred form of the present invention is clearly shown.

In the drawings: Figure 1 is a 'cross sectional view of a power transmission incorporating a preferred form of the. present invention.

Figure 2 is a diagrammatic view of the hydraulic circuits employed in the invention. 1 Figure 3 is a fragmentary side view of a hydraulic power transmission forming part of the a variable displacement fluid pump 32. The output shaft 30 of the motor may be connected by sists of a variable displacement fluid motor 20 and suitable driving connections, shown more fully in my aforesaid Patent No. 2,168,655, to a drawworks drum while the input shaft 34 of the pump maybe connected by other driving connections to a suitable prime mover such as 9. Diesel engine.

The details of the drilling rig being of no concern in the present invention, they are-not illustrated herein. Normally such a rig comprises a draw-works or winch by which the tool string 'may be raisedor lowered-in the hole together with suitable rotary driving means whereby the "kelly or squared section at the top end of the string may be rotated. The tool string issuspended from a block and falls in the derrick by means of a swivel fluid to the interior of the tool string. The power transmission and control system therefor includes a stroke varying hydraulic motor 92 for the variable displacement pump 32 and a stroke varying hydraulic motor 94 for the variable displacement motor 20. The motor 28 and pump 3-2 are illus trated as of the Waterbury construction comprising revolving cylinder barrels within which pistons 98 are reciprocated by the motion of socket rings I 00 which revolve in tilting boxes I02 and I04.

The tilting box I02 carries a stud I05 having a pivoting and sliding connection with a difierential piston I00 mounted in cylinder bores H0 and I I2 of the hydraulic motor 92. The bore H2 is subjected to a constant fluidpressure from an auxiliary pump II4 (see Figure 2), through a con- .duit IIB while the bore H0 is subjected either to pressure responsive pilot valve I26 at certain times, and at other times is subjected constantly to auxiliary pump pressure.

A movable valve member I20 of the pilot valve I26 is mounted in a bore I30 of the pilot valve I26 and has a reduced diameter stem I32 projecting through the bottom wall of the bore I30 and carries two piston heads I34 and I30. The lower end of the bore is in communication through a conduit I39 with the working circuit of the hydraulic transmission preferably through a shuttie valve I40 as indicated in Figure 2 whereby the side of the working circuit which is of higher pressure at any instant is placed in communication with the lower end of the bore I30. An adjustable spring I42 urges the valve member I28 downwardly against the pressure exerted in the lower end of the bore I30. A conduit I44 is normally closed by the piston I30 and is opened to the exhaust side pressure at the interior of the case of the motor 20 through a passage I46 when valve member I23 moves downwardly while communication is established between conduit I44 and the auxiliary pump II4 through' a conduit I40 when the valve member I20 is moved upwardly.

- The fluid motor 92 is under the control of a manually operable follow-up valve I50 which comprises a plunger I52 'slidable in a bore I54 formed in the small end of the piston I00. The bore I54 is in communication with the interior of the case ofthe pump 32 through a passage I56. The plunger I52, is formed with a groove I58 communicating with the bore I54 by a passage I60 and a groove I 62 communicating with the cylinder bore II2 through a passage I64. The piston I08 formed with a bore I06 leading from the cylinder II to a groove I58 ,(see Figure which connects a radial bore I with a diametrically opposite radial bore I 12. Longitudinal movement of the plunger I52 in either direction from the position illustrated thus opens a connection either from-the cylinder bore I I2 or from the bore I54 to the bore I55, leading to the cylinder H0 and thus causes movement of the piston I08 in a manner to follow up the movements of the plunger I52. The plunger I52 is controlled manually through a collar I41 and a fork I49 (Figure '7) which may be connected to a suitable control handle, not shown, adjacent the drillers station.

Plunger I52 is adapted to be rotated angularly about its axis in order to move grooves I58 and I52 out of register with the radial bores I10 and I12 as illustrated in Figure fi. For this purpose, a sleeve I14 is mounted adjacent the end of the cylinder H2, and is connected to the plunger I52 by a sliding key I15. An arm I18 on the sleeve I14 may be moved to rotate the sleeve I14 and plunger I52 as desired without affecting the longitudinal position of the plunger I52.

For the purpose of automatically controlling the tilting box I02 to maintain the horsepower delivered by the transmission at a constant maximum, certain valves are provided capable of predominating over the control exercised by the plunger I52. Referring now to Figure 2, a speed governor operated valve I80 is provided, having a movable member I82 provided with a piston head I84 for controlling the passage of fluid between a conduit I85 and the interior of the casing of the pump 32. The member I82 is operated by means of an arm I88 which is controlled by a speed governor I90 responsive to the speed of the shaft 34 of the pump 82. The arm lies in a downward position, illustrated, at normal pump speeds and moves upwardly whenever the pump speed falls below normal, to connect conduit I85 with the interior of the casing through a conduit.

A piston head 200 is subjected to pressure from the shuttle valve I40 through a conduit 202 which is counteracted by an adjustable spring 204 so that when the pressure in either side of the working circuit rises beyond a predetermined safe value the valve member I94 rises to connect the conduit I98 with the interior of. the

I casing of the pump 32 through a conduit 205.

A selector valve 208 is provided for manually transferring control between the automatic constant horsepower control used during hoisting of the drill stem from the well and the automatic constant weight control used while drilling. For this purpose the valve 208 is provided with a movable member 2I0 having pistons 2I2,

2I4, 2 I5 and 2 I8. A conduit 220 leads to the body of the valve 208 between the pistons 214 and 2I5 and is connected to the outlet-line 222 of the auxiliary pump II4.- A conduit 228 connects to the body of the valve 208 between the pistons 2 and 2I5 and leads to the cylinder I22 of the motor 94. Between the piston heads 2I5 and 2I8 the conduit I44 connects to the body or the valve 208. Between the piston heads 2I2 and 2I4, a conduit 224 connects to the body of the valve 208 and leads to a pilot control valve 225,

laterto be described. Between the heads 2I2 and 2 I4 a conduit 228 connects to the valve body and leads to the cylinder H0 or the motor 92. To the left of the piston 2I2 a conduit 230 connects to the body of the valve 208 and leads to the conduits I85 and I98. A bore, not shown, is provided longitudinally 'through the center of the member 2 I0 for connecting the extreme end spaces of the valve body together.

In the position of the valve 208 illustrated in Figure 2, which is the position for constant weight control, the cylinder I 22 is subjected to control by valve I25 through the conduits I44 and 223. The cylinder '0 is cut off from control by the pilot valve 225 and is subjected to control by the speed responsive valve I and pressure responsive valve I92 through conduits 228 and 230. The valve 208 is controlled from a stem 232 which is connected toa suitable control handle, not shown, adjacent the drillers station. A control rod 238 is also connected to the same handle and operates a bell crank 240 which is connected by means of alink 242 to the arm I18 of the sleeve I14 so that when the valve 208 is moved into drilling position thesleeve I14 is turned to move the grooves I58 and I52 out of register with the bores I10 and I12. The

- passages I50 and I54 are somewhat smaller than the passages between cylinder I I0 and the exhaust side of the system through valves I80 and I92 so that during.constant horsepower operation, the valves I80 and I 92 may predominate over the follow-up valve I50.

Referring to Figure 5 which shows the mechanism for controlling the'weight on the drilling bit, the cylinder 84, which is mounted 'at the top of the kelly 18, includes a cover 244 having a central bore through which a circular stem 245 may slide, which bore is sealed with a packing member 248. The stem 245 carries the bail 80 at its upper end and is provided with a piston 250 at its lower end having a fluid tight sliding fit in the interior bore of the cylinder 84. Piston 250 carries a valve 252 adapted to control-the passage of fluid from the top to the bottom of the piston 250. For thispurpose the piston is provided with a bore 254 having an enlarged portion 255, the bore 254 being adapted to receive a piston member 258 of the valve 252. Passages 250 extend from the bore 254 to the lower side of the piston 250. cordance with the position of the piston 250 relative to the cylinder 84 by means of a lever 252 pivoted at 254 and having a heel 255 adapted to rest on the bottom surface of the cylinder 84. A spring 251 constantly urges the valve 252 downwardly and holds the heel 255 against the bottom of the cylinder 84.

A conduit 258 is formed in thestem 245 to communicate with the space above the piston 250 and terminates in a pipe 258a which is connected by a flexible hose, not shown, to the transmission control mechanism. A conduit 210 extends from the lower face of the piston 250 through the stem 245 and terminates in a pipe 210a which is connected by a flexible hose, not shown, to the transmission control mechanism. The conduit 258 is connected to the outlet of a second auxiliary pump 212 and to a port 214 in the pilot valve 228. The conduit 210 is connected to the inlet of auxiliary pump 212 and to a port 218 in the pilot valve 225. The pilot valve 225 has a movable member 218 having piston heads 280, 282, and 284 and is formed with cylindrical end portions 285 and 288 receivable in bores 290 and 292 The valve 252 is controlled in acof the valve housing. A .conduit 294 extends through the movable member 218 to connect the bores 290 and 292. An adjustable spring 296 controlled by a screw 291 yieldingly urges the valve member 218 to the right. The position of the movable member 218 is' then determined by the difference in pressure between the conduits 268 and 210 which in turn is determined by the pressure drop across the valve 252. A conduit 216 serves as a drain for the end chambers of valve 226.

The piston 282, when the member 218 is in mid-position is adapted to close a port 298 comdischarge conduit 222 of the auxiliary pump -I I4.-

When the valve member 218 is moved to the left communication is established between the port 298 and a port 304 communicating with a conduit 306 which leads to the return conduit 308 for the auxiliary pump II4. The conduit 308 is in communication with the usual expansion tank 3I0 which is also connected by conduits, not shown, with the interior of the casings of the motor 28 and the pump 32.

A relief valve 3l2 connects by conduits 3l4 and 3I6 with the outlet and the inlet of the pump I I4 for the purpose of limiting the pressure developed in the conduit 222. A relief valve 3I8 is interposed in a conduit 320 leading from the conduit 302 to the conduit 210 for the purpose of replenishing fluid in the system fed by the auxiliary pump 212. The valve 3| 8 may be set so that a predetermined drop in pressure in the low pressure conduit 210 permits fluid to pass from the conduit 302 to the conduit 210 until the pressure in the latter rises to normal operating value. A relief valve 322 is also provided in a conduit 324 leading between the conduit 210 and the return conduit 308 for the auxiliary pump II4. The valve 322 is preferably set to open at a'predetermined pressure rise above normal in the low pressure conduit 210. Conveniently the conduit 210 may be maintained at a range of pressures between atmospheric and 25 lbs. per sq. in. thereabove. Thus the valve 322 would be set to relieve at 25 lbs. per sq. in. while the valve 3 I 8 would be set to relieve at the same value at which the valve 3I2 is set. The auxiliary pumps II4 and 212 may be driven from the shaft 34 by a belt drive 328 while a belt drive 328 operates the speed governor I90.

In operation of the device when it is desired to hoist the drill stem, the selector valve 208 is moved to the lefthand position, in Figure 2, in which sleeve I14 holds the grooves I58 and I62 in register with the bores I and I12, and the speed of hoisting may be controlled by shifting the plunger I52. Thus; if the plunger I52 is moved to the right, Figuresl and 2, fluid will be admitted to the cylinder IIO from pump II4 through the conduits 222, and H6, cylinder II2, conduit I64, groove I62, bore I12, groove I68 and bore I66. The piston I08 will thereby move to the right by the same distance that the plunger I52 was moved to the right and the tilting box I02 will be moved into stroke in a direction. causing the hoist drum l8 to wind cable thereon and lift the drill string. Conveniently the plunger I52 may be thrown to its limit so that the tilting box I02 will be moved into full stroke if the weight of the drill string is such as to permit hoisting at as this pressure reaches a predetermined point,

for example 500 lbs. per sq. in.; valve member I28 lifts, permitting fluid from the auxiliary pump II4 to flow through conduits 222, I48 and I44,

valve 208 and conduit 223 to the cylinder I22,-

thus moving the piston I20 to the left and placing the tilting box I04 in full stroke position. As the piston I08 continues to move to the right ,a

point is reached where the speed of hoisting is such that the maximum horsepower of the prime mover is utilized. Any movement of the tilting box I02 beyond this point causes the prime mover to fall ofi in speed which accordingly operates the speed governor I90 to lift the valve I80. As soon as valve I80 lifts the cylinder 0 is opened to the exhaust side of the system through conduits 228, valve 208, conduits 230 and I86, valve I80 and conduit I85. Movement of the tilting box I02 is therefore prevented beyond a position at which the speed of hoisting is such as to use the full horsepower of the prime mover.

As the weight of the drilling stem is gradually decreased by progressive removal of sections thereof. the tilting box I02 moves further toward.

full stroke position at each time the plunger I52 'is operated to hoist. When the weight of the stem decreases sufliciently so that the tilting box I 02 can move into full stroke position without slowing down the prime mover, the transmission operates at one to one ratio until a further decrease in the weight of the stem permits the valve I26 to drop thus opening the cylinder I22 to the exhaust side of the system through conduit 223,

. valve 208, conduit I44, valve I26'and conduit I46.

The piston I20 thereby moves to the right until the strokeof the motor 28 has decreased sufliciently to maintain the pressure at which the valve I26 is set. The hoisting speed is thereby increased to the point where the full power of the prime mover is utilized. As the weight of the stem further decreases, the stroke of, the motor 28 is correspondingly decreased until the minimum stroke is reached at the point where string.

The drill string may be fed into the hole again as sections are added thereto by permitting the drill string to fall of its own weight in the usual manner. When the drill string has been completely. fed into the hole, drilling may be resumed by operating the handle to shift the selector valve 208 and the sleeve I14 into drilling position. Under these conditions the auxiliary pump 212 delivers fluid through the conduit 268 through the upper chamber of the cylinder 84. sure maintained in this chamber is determined by the setting of the spring 296 which may be adjusted to maintain any desired proportion of the total weight of the drill stem suspended from the traveling block. As drilling proceeds the drill stem is fed downwardly as required to maintain the weight on the drillingbit constant. Thus as the drill makes hole the resulting small increase in the weight suspended on the traveling blocktends to pull the cylinder 84 downwardly thus tending to close the valve 252 and increase the pressure above the piston 250. The valve The pres- Y member I'll is thereby moved to the left permitting fluid to flow from the cylinder Ill through conduit Ill, valve Ill, conduit 2, port 2", port I, conduit 3" and conduit III to the exhaust side of the systenn The piston III is thereby moved to the leit in Figure 2 to move the tilting box ll! slightly into stroke in the lowering direction until the desired weight is again maintained on the drilling bit. During normal operation the mechanism tends to reach a state of equilibrium with tilting box III in a slight stroke in the lowering direction such that the drill is fed downwardly at the same rate at which the bit "makes hole. Should the drill be led downwardly too rapidly the cylinder .4 will tend to rise, thus opening the valve "2 wider and permitting valve member 2" to move to the right. Fluid from the auxiliary pump III is thus permitted to pass through the conduits 222 and 102, port I", port "I, conduit I24,

valve 208 and conduit m to the cylinder H...

The rate of feed is thus adjusted to correspond circuit ior maintaining-fluid under pressure in one end oi the cylinder, a valve for variably passing iluid from said one end of the cylinder, means for operating said valve in accordance with relative movement between the piston and cylinder, a valve responsive to variations in pressure in said end of the cylinder, and means controlled by the last mentioned valve for bodily moving the cylinder and piston assembly.

2. A fluid pressure operated control system comprising a cylinder and piston mounted for relative movement in accordance with changes in a quantity to be controlled, a fluid pressure circuit for maintaining fluid under pressure in one to the rate at which the bit makes hole and I in a quantity to be controlled, a fluid pressure end of the cylinder, means for varying said pressure in accordance with relative movement between the piston and cylinder, a valve responsive to variations in said pressure, and means controlled by said valve for bodily moving the cylinder and piston assembly.

3. A fluid pressure operated control system comprising a cylinder and piston mounted for relative movement in accordance with changes in force transmitted from one to the other, a iiuid pressure circuit for maintaining iluid under pressure in one end oi the cylinder, a valve 101' variably passing fluid from said one end oi the cylinder, means tor-operating said valve in accordance with relative movement between the piston and cylinder, a valve responsive to variations in pressure in said end of the cylinder, and

means controlled by the last mentioned valve ior bodily moving the cylinder and piston assembly.

EDW'INLROBI.

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