US2671316A - Hydraulic control system - Google Patents

Description

March 9, 1954 R. s. MILLER ET AL HYDRAULIC CONTROL SYSTEM 3 Sheets-Sheet 1 Filed April 28, 1949 INVENTORF 242mm: .5 M/UE? 61-7926! w swam/0 47704NEK5 arch 9, 1954 Filed April 28, 1949 R. S. MILLER ET AL HYDRAULIC CONTROL SYSTEM 3 Sheets-Sheet 2 570M PUMP 4/ IN VEN TOR5 REC IEF VAL l/E arch 1954 R. s. MILLER ET AL HYDRAULIC CONTROL SYSTEM 3 Sheets-Sheet 3 Filed April 28, 1949 INVENTOR5 Mme/w .i/f/AZIP Patented Mar. 9, 1954 HYDRAULIC CONTROL SYSTEM Raymond S. Miller, Hollywood, and George W. Sinclair, Los Angeles, Calif., assignors to M. 0. Johnston, Glendale, Calif.

Application April 28, 1949, Serial No. 90,254

13 Claims.

This invention relates to a fluid pressure system and to control means therefor. More particularly, it relates to an hydraulic system for erecting and operating a portable, collapsible rig used in drilling and servicing oil wells.

The fluid pressure system of this invention has particular application to the erection and operation of a rig such as described in copending application of Mac J. Kinsey et al., Serial No. 89,322, filed April 23, 1949, now abandoned, entitled "Portable Drilling Rig.

An object of this invention is to provide a fluid pressure system and control means therefor which can be operated from the cab of a vehicle carrying a collapsible drilling rig for erecting the rig, and which can also be remotely controlled after erection of the rig and during drilling and servicing of the well, at some point of vantage.

It is a further object of this invention to pro vide a fluid pressure system which is operable to handle large volumes of liquid under pressure to control the operation of a plurality of hydraulic cylinders, each having a large piston area and a long piston stroke.

It is a still further object of the invention to provide a fluid pressure system which combines safety features and features of automatic operation rendering the erection and operation of a large oil well derrick simple, expeditious and safe.

One form which the invention may assume is exemplified in the following description and illustrated by way of example in the accompanying drawings, in which:

Fig. l is a diagrammatic view of the hydraulic control system of the invention and of a group of hydraulic cylinders controlled thereby.

Fig. 2 is a view in section of the valve means for controlling the hydraulic ram and auxiliary or cat cylinders during erection of a portable rig.

Fig. 3 is a more or less diagrammatic View showing the main part of the control system of Fig. 1 in detail.

Referring now to the drawings and more particularly to Fig. 1, there is shown an hydraulic control system generally designated as I and a group of hydraulic cylinders generally designated as I I. The hydraulic cylinders II are of the nestable tube type, and they are described in detail in the copending application above-mentioned. Only so much of their structure and operation is described herein as is necessary to an understanding of the present invention.

Two main cylinders I2 are shown, each having a liner I3, a piston It reciprocable in the liner and nestable, telescoping tubes I5 secured at the top to the cylinder and at the bottom to the piston. The liner I3 is spaced from the cylinder to provide an annular space I'Ia for passage of fluid to and from the liner. An air pressure line I6 communicates with each cylinder I2 beneath th piston, and an hydraulic pressure line I! communicates with the annular space Ila between the liner and cylinder. An air bleed line I8 is provided, as illustrated, and a cable or wire line I9 is attached at one end to the piston, is led over a sheave 20 and is attached at its other end to a hook 2 I which serves to carry a load.

It is apparent that, as hydraulic pressure is supplied to the main cylinders I2 through lines I1, the pistons I4 will be depressed against the air pressure therebelow and the hook 2I will be lifted, thus lifting a load or doing other useful work. If hydraulic pressure is held steady in the main cylinders, the load will be held stationary, and if hydraulic pressure is bled from the cylinders the load will be lowered.

As also illustrated, the main cylinders are sectional in construction, comprising upper and lower sections I2a and I2b, respectively, coupled at 22.

A pair of auxiliary or cat cylinders 30a and 30b are also illustrated, these being similar in construction and operation to the main cylinders. Each cat cylinder has a liner (H in which a piston 32 is reciprocable, and nestable tubes 33 and a cable or wire line 34 led over a sheave 35 are also provided as illustrated. An air pressure line 36 and an hydraulic pressure lin 31 are provided, as in the case of the main cylinders. As also illustrated, an hydraulic ram 40 is provided for use during erection of the derrick as described in the above-mentioned copending application.

The hydraulic ram 40 is operated by a pair of parallel pumps M (of which only one is shown). For simplicity, only one such pump 4| will be referred to hereinafter. Pump 4| is preferably a positive displacement pump capable of developing a high pressure, e. g. 1800 p. s. 1., such as needed during erection of the derrick described in the above-mentioned copending application. Pump 4| is also used to operate the cat cylinders 30a and 3% during erection of the derrick. Centrifugal pumps 42 and 43 are used to operate both the cat cylinders 30a and 30b and the main cylinders I2 after erection of the derrick and during drilling and servicing of a well. The reason for this arrangement of pumps is, that during erection or rigging up a high pressure is of major importance while speed and the rapid handling of large volumes of liquid is of lesser importance. But during drilling or servicing a well, lower pressures are acceptable but the pumps should be capable of rapidly handling large volumes of liquid for the sake of speed. Centrifugal pumps capable of delivering 950 p. s. i. are suitable for this purpose. Pump 4| and pumps 42 and 43 are operated by engines 44 and 45 through suitable mechanical linkages (not shown) including clutches (not shown) to disengage either set of pumps while the other set is operating. Engines 44 and 45 are throttled as follows: A lever 50 is connected by a mechanical linkage to an hydraulic servo unit 52 which is connected through lines 53 and. 54 to hydraulic slave units 55 and 56 which in turn are connected to engines 44 and 45 by mechanical linkages 51 and 58, respectively. On moving lever 50 upwardly as viewed in Fig. 1 from its neutral position, the engines 44 and 45 are accelerated through the medium of the hydraulic units 52, 55 and 56 and fluid links 53 and 54.

During preliminary operations such as rigging up a portable derrick of the character referred to, when maximum pressure is desired, the ram 40 and cat cylinders a and 3012 are operated by positive displacement pump 4| through the medium of control levers 5e and 50. controls the ram and lever 60 controls cat cylinders 33a and 30b. In Fig. 1 the control systems for the ram and cat cylinders are shown in simplified form and in Fig. 2 they are shown in greater detail. Referring to Fig. 1, the conunder pressure passes through a line I0 having a check valve ll to the valve structure 56, thence through a line I2 to the ram. When pressure is bled from the ram, fluid passes back through the line I2 to valve structure 66, thence through a line I3 to line 68 and back to reservoir 6'1. line i4 is also provided for telescoping the ram in the manner described hereinafter.

Control lever 63 for cat cylinders 30a and 30b is connected by a mechanical linkage 80 to a valve structure 8|. and are throttled by lever 50. Lever also controls valves 82 in lines 83 which lead to the cat cylinders, by means of a slip link 84 of known construction. Thus, when lever 50 is in its neutral position, slip link 84 holds valves 82 in closed position; i. e., it prevents pressure draining from cat cylinders 30a and 3% when pump 4| is not developing a pressure. When, however, lever 50 is advanced to accelerate engines 44 and 45, slip link 84 is released and valves 82 may be operated by a lever 85.

Still referring to Fig. 1, and assuming that valves 82 are open, pressure reaches the cat cyl-' inders from pump 4| through a line 86, valve structure 8|, a line 81, valves 82, lines 83 (which also contain throttle valves 88) and lines 31. Pressure is bled from the cat cylinders through lines 31 and 83 (throttle valves 88 serving to restrict the rate of bleed), valves 82 and line 81 to valve structure 8|, thence through a line 89 to line I3 and to the reservoir 61.

Referring now to Fig. 2, ram control valve 66 comprises a tubular housing I00 within which a piston IOI i reciprocable. The piston IOI is operated by a lever 59, and it is formed with lands I02, I03 and I04. Ram 40 comprises the usual telescopic section 40a, 40b and 400. Section 40a is formed with longitudinal passages I05 and I06. Passage I05 extends through a piston I0'I formed as part of section 40a. while passage I06 opens Lever 53 As stated, the engines 44 and I05 communicate with lines I2 and I4, re-

spectively.

To extend the ram 40, lever 59 is moved to the right as viewed in Fig. 2, thus moving piston IOI to the right and communicating ports I08 and I 09 formed in the housing I00. Pressure passes to the ram through line I0, ports I08 and I09, line 72 and passage I05, thus extending the ram. To hold pressure in the ram at any given position, lever 59 is returned to its vertical, neutral position. Land I03 shuts off pump pressure through port I08, and the pump communicates with the reservoir 61 through a passage I I0 and a port III formed in housing I00, a line II2,

ports H3 and II4 formed in valve structure 8|, a line H5 having a check valve H6 and line I3. Pump pressure is maintained in ram 40 through a line II'I leading from line M5 to line I2, as shown, and having a check valve IIB.

To bleed pressure from the ram, lever 59 is moved to the left, thus moving land I03 so as to uncover port I09 and cover port I08 and moving land I02 to uncover a port I25. Pressure drains from the ram through line I2, port I09, a port I25 and a line I21, thence through a port I28, a passage I29 and a port I30 formed in valve structure 8| to line 89, and then through line I3 to the reservoir 6?. Meanwhile, pump pressure is delivered through line I0, ports I08 and I25 in housing I00 and line I4 to passage I06 insection 40a of the ram, thus exciting a thrust on the lower end of section 4012 and forcing the ram to telescope.

During operation of the ram 40, cat cylinder control lever 60 is maintained in neutral position as illustrated. When it is desired to operate the cat cylinders, the ram control lever 59 is returned to neutral position. To supply pressure to the cat cylinders, lever 60 is moved to the right. It will be seen that lever 60 operates a piston I3I which is reciprocable in housing I32. The piston I3I is provided with lands I33, I33a, I34, and I35. When lever 50 is moved to the right, fluid pressure passes from the pump4| through line T0, ports I03 and I35 in housing I00, a line I33, ports I38 and I39 in housing I32 and line 81 to the cat cylinders, Fluid pressure also passes through a passage I32a formed in hous ing I32 to a recess or cavity I320 and therefrom to port I54 which is uncovered by land I33.

To hold pressure in the cat cylinders, lever 60 is returned to neutral position, thus closing port I39 to prevent return of pressure therethrough and holding pressure in the cat cylinders.

To bleed pressure from the cat cylinders, lever 60 is moved to the left, thus communicating port I30 with passage I29 and allowing pressure to bleed through line 87, port I39, passage I29, port I30, line 89, etc. back to the reservoir.

As is also shown, the valve housings I00 and I32 are formed with recesses I40 and I4I, respectively, communicating through a line I42, a port I 43 and a passage H24 communicating with port I30 and thence with the reservoir. Thus, provision is made for bleeding off fluid that may leak past lands I52 and I 3a. Also, provision is made for relieving m5 pressure in excess of the pressures for which the ram and cat cylinder are designed. Ihus, in a typical case the ram 40 is designed for a maximum pressure of 1800 p. s. i. and the,cat cylinders 30a and 30b for a maximum pressure of 900 p. s. i. For the purpose of relieving excess pressure, pressure relief valves I50 and I5! of the Vickers C-l67 typeare provided. These valves are of standard; well known type and require no detailed description here. Valve I53 will be set to open at 1800 p". s. i. when activated by pump pressure through a: line I52 and at a lower pressure when actuated through a'line I53. Valve I-EI willbeset'toopen' at 900 p; s. i. when actuated by pump pressure through a port I54 in housing I32 and a line I55- and itcommunicates with valve I5El through.

the line I5'3Z' Thus; when the ram 40 is openating, land I 3 3 will close port- I54- (-thus' keeping pump'pressure from opening valve I5-I If pump pressure exceeds 1800 p". s. i., valve I BB will open and pressure will bleed through a line I56 to the reservoir. When the pump pressure returns to 1800 p. s. i., valve I56 will close.

When the cat cylinders 30a and 302) are operating and pressure is being supplied thereto, land I 3"3 will have been move to the right to open- 60 and 85, which may be conveniently located in the cab of'a vehicle employed to carry the derrick along with other elements of the rig such as the engines 44 and 45 and pumps 4i, 4: and 53. When the derrick has been erected and is ready for operation todrill or service a well, a control panel I'll) (see Fig. l) is setup at some point of vantage where the operator or derrickman has an unobstructed view of the derrick.

The control panel lid is of conventional construction and requires no detailed description. Thus it comprises a master control lever Iii which rides in an H-shaped slot (not shown) and is, therefore, capable of movement to the left and right in a horizontal plane and is also capable of movement up and down at either end of its horizontal travel. Briefly, movement of lever I'lI to the left places the pumps 42 and 43 in parallel and movement thereof to the right places the pumps 62 and 43 in series. Movement of the lever I'll downwardly accelerates the engine 44 and 45 and thus delivers pump pressure, while movement of this lever upwardly from its neutral position controls pressure bleed from the main cylinders l2. Leftand righthand cat cylinder control levers I12a and H2?) are also provided. Movement of the cat cylinder control lever IlZa downwardly from its neutral position accelerates the engines 44 and 45' and thus delivers pressure to the left-hand cat cylinder 3021, while movement of such lever upwardly from its neutral position controls pressure bleed from the left-hand cat cylinder. Similarly, downward and upward movement of the right-hand cat cylinder control lever Il2b from its neutral position, delivers pressure to the right-hand cat cylinder or controls pressure bleed therefrom, respectively.

Valve structures H3, Ht, lit, I76 and I'll con trol the main cylinders i 2, while valve structures use and I 781) control the left-and right-hand cat cylinders 38a and 38?), respectively. Valve structures IlBa and IBb are identical and they are described in detail in copen' ing applicat on of Raymond S. Miller et al., Serial No. 89,321, filed April 23, 1949, now Patent No. 2,639,693

issued May 26, 1953, entitled Hydraulic- Control' Valve and System. Valve structure I13" is: de-- scribed in detail in copendi'ng application" of. Raymond S. Miller; Serial No. 89,3'26,' filed April 23, 1949- (now abandoned), entitled System Check Valve.

Each of the control levers I1 I, H211" and' H211 has a mechanical linkage generally designated; as I19 with a servo unit" Hi0- connected by -lin'e's IBI and I82 with hydraulic slave units I 83 and I84, which-control engines 44 and 45, respectively. As stated, down-ward movement of any of thecontrol levers Ill, I'lZctand- I'l2'b operates" to accelerate the engines t l and 45 and thus tod eliver'pump pressure to the cylinders.

The left-hand cat cylinder control lever Il2'aalso has av mechanical connection designatedas I85 with a servo unit I85 which is connected by lines I81 with an hydraulic unit I88 and through lines I81 and I with an hydraulic unit I96 which is op'eratively connected with" and formsa part of the left-hand cat cylinder control valve structure I'lEa. cylindercontrol lever I'l2b has" a mechanical connection I88 with a. servo unit I88 and through lines 260' and 2M with an hydraulic unit. 202* which is operatively connected with and forms a part of the right-hand cat cylinder control valve structure I782).

Master control lever I'll. is connected by a mc chanical linkage 29 3' with a servo unit 295 and by a mechanical linkage 286 with a servo unit 201. The servo unit2ll5 is connectedby lines 288 to an hydraulic unit ZBiiwhich is op'eratively connected to and forms a part or the valve structure I15. Since servo unit 205 and hydraulic unit 209 are connected by two lines (see lines 2&8, Fig. 3), piston 226 will be moved to the right or left when lever I'll is shifted to the right depending only on how lines 208 extending from unit 2 .35am connected to unit 289.. In the present instance, the lines are connected so that when lever Ill moves to the right, piston 22% is moved to the left, and consequently when lever I?! is moved to the left, piston 225' will be moved to the right. Servo unit 2'il'l is connected by lines 2II with an hydraulic unit 2l2 which is operatively connected to and forms a part of valve structure I14. Hydraulic unit; M2 is also opera-*- tively connected to a valve 2I3 bym'eans generally designated as 214.

lli'rv pressure for the system is provided. by a compressor unit 220 connected to a reservoir 22f through a line 222. Other elements of the air pressure supply and relief means are. described hereinafter in connection with the operation" of the system.

It will be understoodthat Fig. 1 is greatly simplified. Further details are provided hereinafter with particular reference to Fig; 3.

As stated, if it is desired to operate pumps 42 and 43 in series (for greater pressure), master control lever I'll is moved to the right, and if it is desired to operate the pumps 42 and 13. in parallel, lever I1! is moved to the left. This control is effected in the following manner.

Referring to Fig. 3, it will be seen that unit 203 comprises a tubular housing 225 in which a piston. 226 having a stem 22? and lands 223 and 229' is reciprocable. As is also shown in Fig. 3, valve structure I'l'5 comprises a valve 230 contro ling a port 23I' and operated by a piston 232 reciprocable in a chamber 232a; Assuming it is desired to operate the pumps 42' and 43in series, lever lll' is moved to the right, thus activating Similarly, the right-hand cat servo-unit 205 which causes the fluid to flow through lines 208 in such a direction as to drive piston 226 to the left, thus communicating a port 233 with a port 234. Pump pressure in a line 235 reaches port 233 through lines 236 and 231, and passes thence through port 234 and a line 238 into chamber 232a beneath piston 232. Thus piston 232 is quickly elevated and valve 230 is quickly opened. Fluid from reservoir 61 passes through lines 13 and 239 to pump 42, thence through a line 245 and port 23I to pump 43. A check valve 246 in valve structure I16 controls a port 241 communicating with reservoir pressure in a line 248. Obviously, since pump pressure exists to the left of valve 246 and tank or reservoir pressure to the right thereof, valve 246 will remain closed and the only path by which fluid can reach pump 43 is from pump 42 through line 245, port 23I and a port 249 in valve structure I16. The pumps are, therefore, in series. Pressure passes from pump 43 through line 235 to the cat cylinders or the main cylinders as explained hereinafter.

If it is desired to operate pumps 42 and 43 in parallel, master control lever IlI is moved to the left, thus activating servo-unit 205 which causes the fluid to flow through lines 288 in such a direction as to drive piston 226 of unit 209 to the right and communicating port 233 with a port 250. Pump pressure passes through line 231, port 233, port 250 and a line 25I to chamber 232a above piston 232, thus quickly closing valve 230. Fluid from reservoir 61 reaches pump 42 through lines 13 and 239. Since pressure from pump 42 is unable to reach valve 246, the latter is free to open under the pressure existing in reservoir 61. Fluid therefor reaches pump 43 through line 248 and ports 241 and 249 in valve structure I16. Pressure from pump 42 passes through line 245,

a line 255, and a port 256 in valve structure I1! which is controlled by a check valve 251. (It will be noted that during series operation of the pumps 42 and 43, the pump pressure in valve structure I11 exceeds that in line 255, and that as a consequence valve 251 is held closed.) Pressure from pump 43 passes through line 235. Unit 209 is also provided with ports 258 and 259 which communicate through lines 260 and 26011 with the reservoir, to drain fluid displaced by movement of piston 226.

If it is desired to operate the main cylinders I2, master control lever I'll is moved to the right or left, as desired, to operate pumps 42 and 43 in series or in parallel as described. To supply pressure to the cylinders, lever I1I is moved downwardly from neutral position, thus accelerating engines 44 and 45 and delivering pressure to the valve structure I11 in the manner described.

" It will be seen that valve structure I13 includes a port 265 controlled by. a check valve 266, and a port 261. During operation of the main cylinders, pump pressure in valve structure I11 is free to open valve 266, which thus passes through ports 266 and 261 into a line 288. Pressure then passes through ports 266 and 210 in valve structure I14 into a line 21I, thence into lines I1 and cylinders I2 (see Fig. 1).

Valve structure I14 includes a pilot operated valve 212 controlling a port 213 which communicates with line 243, hence with reservoir 61. To supply pressure to cylinders I2, lever I1I is moved downwardly, and it is of course necessary to close valve 212 so that pump pressure in line 268 will not return to the reservoir through port 213 and 8 line 248. This is accomplished by means of servo unit 201 and hydraulic unit 2I2.

As shown in Fig. 3, unit 2I2 and valve structure I14 form parts of a pilot operated valve mechanism of known type which need not be described in detail. Suflice it to say that when lever Ill is depressed, it actuates unit 2I2 to open a pilot valve (not shown) which admits pump pressure from line 268 above a piston 214 to close valve 212, thus accomplishing the desired result. Alternatively, hydraulic control means acting directly on the piston 214 may be used, of the type described hereinabove with reference to valve structure I15.

To hold pressure in the main cylinders I2, lever I1I is returned to neutral position. Return of pressure to the pumps is prevented by check valve 266 in valve structure I13, and return of pressure to the reservoir through line 248 is prevented by valve 212, which remains closed.

To bleed pressure from the main cylinders, lever I1I is moved upwardly from neutral position. This actuates servo unit 201 and unit 2I2 oppositely with respect to their operation during downward movement of the lever I1I, thus draining pump pressure from above piston 214 and delivering pump pressure therebelow to raise the piston and with it the valve 212. Fluid drains from the cylinders through port 213 and line 248, at a rate determined by the position of lever I1I.

If it is desired to operate the left hand cat cylinder 30a. and to deliver pressure thereto, lever I12a is moved downwardly from its neutral position. This accelerates engines 44 and 45 and provides pump pressure in the manner described hereinabove. It also operates in the manner now to be described to prevent pump pressure from reaching the main cylinders.

Referring again to Fig. 3, it will be seen that hydraulic unit I88 comprises identical slave units 286a and 2801) for the leftand right-hand cat cylinders, respectively. Each unit 280a or 28% comprises a piston 28I reciprocable in a cylinder 282 and having a stem or rod 283 which engages a pawl 284. Each pawl 284 engages a lug 285 on a rod 286 which is urged downwardly by a spring 281 and which has a cam 288 at its upper end. The unit I88 also comprises an hydraulic unit 289 comprising a rod 290 having a roller 280a at one end engaging the cam 288 and lands 29I, 292 and 293 which are reciprocable in a cylinder 294. A spring 295 normally urges rod 290 to the left. Pump pressure is communicated to cylinder 284 through a line 296 and pressure relief lines 231a and 291D are provided for removal of fiuid displaced by movement of the rod and lands.

Hydraulic unit 269 operates a valve mechanism 3I0. The valve mechanism 3I0 comprises pistons 3H and 3I2 reciprocable in a cylinder 3I3 and connected by a stem or rod 3I4 and a land 3I5.

In operation, the unit I88 and valve 3I0 function as follows: When lever I12a is moved downwardly from neutral position to deliver pump pressure to the left-hand cat cylinder, it also actuates servo unit 66 (see Fig. 1) and thereby delivers pressure to the left of piston 28I in slave unit 2800.. Rod 283 is thereby moved to the right and rocks pawl 284. Pawl 284 urges rod 286 upwardly, thus moving land 292 of unit 289 to the right. Pressure line 296 is thereby communicated with a line 3% and moves piston. 3|! of valve 3E3 to the right. Pump pressure from line 23? is thereby permitted to pass through ports 3!? and 358 in valve 3H), thence through a line 319 to valve structure H3. Valve structure 3'53 includes a piston 329 reciprocable in a cylinder 32!. Pump pressure delivered in the manner above mentioned above piston 32?] will act to depress piston 32% and close valve 233. Inasmuch as the same pressure, 1. e., pump pressure, is excited on both'valve 233 and piston 320, and since piston 323 has a greater area, obviously valve 256 will remain closed and pressure cannot reach the main cylinders.

It will be apparent that normally, when both levers Ilia. and H217 are in neutral position, pressure will be applied to. piston 3E2 of valve 3"), through a line 313a. Thus, except when pressure is being supplied to one of the cat cylinders; valve 256 of valve structure (l3 will be free to open. However, it will also be apparent that if pressure is being supplied to either of the cat cylinders, one or the other of the slave units 283a and 28th will act to hold valve 266 in closed position.

Pressure reaches the left-hand cat cylinder 30a through line 236, valve structure Him, a line 322 and line 37. Valve structure [13a is operated by lever 112a, servo unit I88 and hydraulic unit I96. The valve structure H311 and hydraulic unit I93 are shown diagrammatically and in greatly simplified form in Fig. 1 but are shown in greater detail in Fig. 3.

Referring to Fig. 3, hydraulic unit [33 comprises two slave units 320 and 323 which are actuated oppositely by servo unit I 56. Unit 323 operates a valve 324 through the medium of a pilot valve (not shown) and a piston 325. Valve 324 controls an inlet port 323 and it is provided with a spring 321 so as to act as a check valve. Similarly, unit 323 controls a valve 328 through the medium of a pilot valve (not shown) and a piston 329. Valve 328 controls an outlet port 333.

Valve structures 118a and hydraulic unit I95 are described in detail in the above-mentioned Patent No. 2,639,693.

In operation, when the left-hand cat cylinder control lever ll2a is moved downwardly from neutral position, and engines 14 and 45 are thereby accelerated, slave unit 323 operates to open inlet valve 323 and slave unit 323 operates to close outlet valve 323. Pressure is thus delivered to the left-hand cat cylinder 33a at a rate determined by the position of lever 11242. If it is desired to hold pressure in the left-hand cat cylinder, the lever ll2a is returned to neutral position. Valve 324, acting as a check valve, prevents return of pressure to the pumps and valve 328 remains closed to prevent bleed of pressure to the reservoir.

If it is desired to bleed pressure from the lefthand cat cylinders, lever N20. is moved upwardly from neutral position, thus actuating servo unit H36 which in turn actuates units 320 and 323 so as to open outlet valve 328, thus allowing pressure to bleed from the left-hand cat cylinder through lines 37 and 322, a line 33!, port 339. a line 332, and lines 239 and '53 to the reservoir 61. The rate of bleed is controlled by the position of lever 112a.

The right-hand cat cylinder 33b is operated similarly by lever I721), servo unit we, hydraulic unit 2112 and valve structure 17.312. Unit 262 and valve structure 13-31) are identical with unit 33 1d and valve structure 118a, respectively, and slim-- ilar parts are similarly numbered.

As stated hereinabove, air pressure for the main cylinders 12 and cat cylinders 30a and 30b is provided by a pump 223. Air reservoir 221 is connected through a line 349 to lines [6 and 36 which communicate with the main cylinders l2 and cat cylinders 32a and 3%, respectively. Thus. air pressure is maintained at all times in these cylinders beneath their respective pistons, to assist in elevating the pistons and to provide a cushion when the pistons drop. Line 349 is provided with valves 34! and 34.2 for a purpose explained hereinafter. Air bleed lines It con met through a three-way valve 343 with a line 344 which communicates with reservoir 31. Air pressure line 3&3 also connects with valve 343 through a line 345.

The air pressure supply and relief system thus described operates as follows: Valve 2l3a in line 344 is normally closed. However, when the main control lever Ill is moved to up position (i. e., when hydraulic pressure is being bled from the main cylinders), hydraulic unit 2l2 is, of course, actuated as described above, and this unit acts to open valve 2l3a, thus allowing air pressure to bleed from the main cylinders. The orifices connecting main cylinders [2 with the air bleed lines [8 are, however, very small so that only an insignificant amount of liquid is lost from the cylinders. However, this bleed is sufiicient to prevent a large accumulation of air in the main cylinders above pistons I l. When lever ill is in its neutral position to hold a load steady it is, of course, important that no pressure be lost from the main cylinders. This object is accomplished by automatic closing of the valve 2 l3a..

When it is desired to dismantle the main cylinders, it is important that the level of hydraulic fluid not exceed the point of coupling 22, and that pressure be relieved from the cylinders before they are uncoupled. This object is accomplished as follows: Air pressure from compressor 220 through lines 340 and [B will elevate pistons 14, thus expelling hydraulic fluid from liners 13. The pistons 14 are latched or otherwise held in elevated position and valve 343 is set to deliver air pressure through air bleed lines 18 to the top of the main cylinders, thus forcing hydraulic fluid out through lines I! to the reservoir until the fluid level is below the couplings 22. Meanwhile, valve 34I will have been closed, and after expulsion of th hydraulic fluid, valve 342 will be opened to vent air pressure from the cylinders, which may be assisted .by lowering pistons 14. The cylinders may then be safely uncoupled and the upper and lower sections l2a and H1) appropriately capped.

It will be apparent that the control means described can be operated by other means than hydraulic pressure, e. g. by pneumatic pressure. The control means and the hydraulic system controlled thereby are flexible and capable of a multiplicity of functions and are characterized by numerous advantages.

Thus, an hydraulic system and control means therefore are provided which are used durin preliminary operations, such as erecting .a portable, collapsible derrick, such system comprising positive displacement pumps capable of delivering a high pressure. The control means for inders, hold pressure in these devices and bleed pressure therefrom. All such operations are subject to exact control.

A main hydraulic system is also provided including a pair of centrifugal pumps capable of handling larger volumes of liquid and also including a pair of main cylinders and a pair of auxiliary cylinders. The control means for this main system is such that the pumps can be operated in series or in parallel and that when the auxiliary cylinders are being supplied with hydraulic fluid, such fluid cannot reach the main cylinders from the pumps. Nicety and rapidity of control are important characteristics of this system and its control means, and numerous safety features are embodied therein so as to ensure rapid and safe operation.

Having thus described our invention, what we claim and desire to secure by Letters-Patent is:

1. An hydraulic system comprising a cylinder,

sure from said cylinder, and control means operable by fluid pressure for throttling said engine and thereby controlling pump pressure and for operating said outlet valve means to bleed pressure from said cylinder when said engine is idling.

2. An hydraulic system comprising a cylinder, a piston reciprocable therein to lift a load when hydraulic pressure is applied to said piston and to lower a load when hydraulic pressure is bled from said cylinder, a pair of pumps, an engine for operating each pump, valve means operable to operate said pumps in series or in parallel, inlet valve means including a check valve operable to feed pressure from said pumps to said cylinder, said check valve being operable to prevent return of pressure to said pumps, outlet valve means operable to bleed pressur from said cylinder, and control means operable by fluid pressure for throttling said engines and thereby controlling pump pressure, for operating said valve means to operate said pumps in series or in parallel, and for operating said outlet valve means to close the same when pump pressure is being developed and for opening the same when said engines are idling.

3. A fluid pressure system comprising a fluid pressure device including a cylinder and a piston reciprocable therein to lift a load when fluid pressure is applied to said piston and to lower a load when pressure is bled from said cylinder, a pair of pumps, engines for operating the same, valve means for operating said pumps in series or in parallel, valve means for controlling pressure bleed from said cylinder and control means for automatically operating said engines and both of said valve means.

4. An hydraulic system comprising an hydraulic device including a cylinder and a piston reciprocable therein to lift a load when fluid pressure is applied to the piston and to lower a load when pressure is bled from said cylinder, a pair of pumps and engines for operating the same, valve means for operating said pumps in series or in parallel, valve means for controlling pressure bleed from said cylinder, and master control means for automatically operating said engines and both of said valve means.

5. A fluid pressure system comprising a main cylinder and an auxiliary cylinder each having a piston reciprocable therein to lift a load when fluid pressure is applied to said piston and to lower a load when fluid pressure is bled from said cylinder, a pump and an engine for operating the same, inlet and outlet valve means for said auxiliary cylinder for feeding fluid pressure thereto and for bleeding pressure therefrom, inlet and outlet valve means for supplying fluid pressure from said pump to said main cylinder and for bleeding pressure therefrom, respectively, and automatic control means operable to control said engine and thereby control pump pressure, and to control said valve means and thereby deliver pressure to or bleed pressure from said cylinders.

6. An hydraulic system comprising a pump and an engine for operating the same, a main cylinder having a piston reciprocable therein for lifting a load when hydraulic pressure is applied to said piston and for lowering a load when hydraulic pressure is bled from said cylinder, an auxiliary cylinder having a piston reciprocable therein for lifting a load when hydraulic pressure is applied to said piston and for lowering a load when hydraulic pressure is bled from said cylinder, inlet and outlet valve means for said main cylinder operable to deliver pressure from said pump to said cylinder and to bleed pressure from said cylinder, respectively, inlet and outlet valve means for said auxiliary cylinder operable to deliver pressure from said pump to said auxiliary cylinder and to bleed pressure therefrom, respectively, and fluid pressure operated control means for throttling said engine and for operating said valve means, to selectively deliver pressure to, hold pressure in or bleed pressure from said cylinders.

7. An hydraulic system comprising a pair of pumps and an engine for each pump, valve means operable to operate said pumps in parallel or in series, a main cylinder having a piston reciprocable therein for lifting a load when hydraulic pressure is applied to said piston and for lowering a load when pressure is bled from said cylinder, an auxiliary cylinder having a piston reciprocable therein for lifting a load when hydraulic pressure is applied to said piston and for lowering a load when pressure is bled from said cylinder, inlet and outlet valve means for said main cylinder operable to deliver hydraulic pressure from said pump to said main cylinder and to bleed pressure from said main cylinder, respectively, inlet and outlet valve means for said auxiliary cylinder operable to deliver pressure from said pumps to said auxiliary cylinder and to bleed pressure therefrom, respectively, and fluid pressure operated control means operable to throttle said engine and to operate all of said valve means to selectively deliver pressure to, hold pressure in and bleed pressure from said cylinders.

8. An hydraulic system comprising a pair of main cylinders each having a piston reciprocable therein for lifting a load when hydraulic pressure is applied to said piston and for lowering a load when pressure is bled from said cylinders, leftand right-hand auxiliary cylinders each having a piston reciprocable therein for lifting a load when hydraulic pressure is applied to said piston and for lowering a load when said pressure is bled from said auxiliary cylinders, a pair of pumps, an engine for each pump, pump valve means operable to operate said pumps in parallel or in series, inlet and outlet valve means for said main cylinders operable to deliver hydraulic pressure from said pumps simultaneously to said main cylinders and to bleed pressure simultaneously from said main cylinders, respectively, inlet and outlet valve means for each said auxiliary cylinder operable independently to deliver hydraulic pressure from said pumps to each of said auxiliary cylinders and to bleed pressure therefrom, respectively, and master control means comprising a fluid pressure means for operating said puma valve means, a fluid pressure means for operating said main cylinder valve means, fluid pressure means for independently operating said auxiliary cylinder valve means, fluid pressure means for operating each engine, and means for actuating each said fluid pressure means.

9. An hydraulic system comprising a main cylinder and an auxiliary cylinder each having a piston reciprocable therein, pump means for providing hydraulic pressure, main cylinder supply means for delivering hydraulic pressure from said pump means to said main cylinder, said supply means including inlet valve means operable by external fluid pressure and also operable as a check valve to prevent return of pressure to said pump means, auxiliary supply means for delivering hydraulic pressure from said pump means to said auxiliary cylinder, said auxiliary supply means including an inlet valve, auxiliary control means operable to open said inlet valve to said auxiliary cylinder, to control pump pressure and to close the inlet valve to said main cylinder by means of fluid pressure, and control means for said main cylinder operable to supply pump pressure thereto and to control pump pressure.

10. An hydraulically operable oil well rig, comprising a pair of upright main cylinders each having a piston reciprocable therein, a wire line for each said cylinder fixed at one end to the piston of said cylinder, right-hand and lefthand auxiliary cylinders each having a piston reciprocable therein, a wire line for each said auxiliary cylinder and fixed at one end to the piston of said cylinder, pump means for providing hydraulic pressure, pump valve means for operating said pumps in series or in parallel, engine means for operating said pump means, fluid pressure operated control means for said engine means operable to throttle the same, main cylinder supply means for supplying pump pressure to said main cylinders and for bleeding pressure therefrom, and including a fluid presure actuated check valve operable as an inlet valve for said main cylinders and as a check valve to prevent return of pressure from said main cylinders to said pumps, auxiliary supply means for supplying pump pressure to said auxiliary cylinders including an auxiliary inlet valve and means for operating the same so as to apply fluid pressure to and close said main cylinder inlet valve when said auxiliary inlet valve is open, other valve means operable to supply pressure independently to said auxiliary cylinders and bleed pressure therefrom, said other valve means being also operable as a check valve to prevent return of pressure to said pumps, and master control means operable by fluid pressure to operate said pump valve means, said engine control means, main cylinder supply means and other valve means so as to automatically supply pressure to, hold pressure in, or bleed pressure from said auxiliary cylinders in unison or separately and to supply pressure to, hold pressure in, or bleed pressure from said main cylinders in unison.

11. An hydraulic system comprising a reservoir for supplying fluid to the system, a flrst conduit from said reservoir to the intake port of a first pump, a second conduit from said reservoir to the intake port of a second pump, a third conduit from the output port of said second pump to an hydraulic motor, a fourth conduit from the output port of said first pump communicating with the third conduit, a fifth conduit communicating said fourth conduit with said second conduit, circuit control valve means adapted to be positively opened and closed, said valve means located in said flfth conduit, a spring loaded check valve located in the second conduit intermediate the reservoir and the communicating fifth conduit, a spring loaded check valve located in the fourth conduit intermediate the communicating third and fifth conduits, inlet valve means adapted to be positively opened and closed and including a spring loaded check valve, said inlet valve means being located in the third conduit intermediate the hydraulic motor and the point of communication between the third and fourth conduits, a return conduit connected to said third conduit intermediate the hydraulic motor and the intake valve means, said return conduit communicatin with said reservoir, outlet valve means adapted to be positively opened and closed for bleeding pressure from said hydraulic motor, said outlet valve means located in said return conduit, an engine for operating said first and second pumps, control means for throttling said engine and. thereby controlling the output of said pumps, and valve control means for positively opening and closing said circuit control valve means whereby when said circuit control valve means is positively moved to the open position said check valves located in said second and fourth conduits move to the closed positions and said pumps operate in a series circuit, and when said circuit control valve means is positively moved to the closed position, said check valves located in said second and fourth conduits move to the open position and said pumps operate in a parallel circuit, said control means being also operable to positively open and close said inlet valve means whereby there is a positive control of fluid to said hydraulic motor, said control valve means also being operable to positively open said outlet valve means to bleed pressure from said hydraulic motor.

12. An hydraulic system as described in claim 11 including a sixth conduit connected to said third conduit intermediate said second pump and inlet valve in said third conduit and communicating with an auxiliary hydraulic motor, inlet valve means located in said sixth conduit adapted to be positively opened and closed, a seventh conduit connected to said sixth conduit intermediate said inlet valve and said auxiliary hydraulic motor and communicating with said reservoir, and an outlet valve means operable to be positively opened and closed, said outlet valve located in said seventh conduit, whereby when said valve control means positively closes said inlet valve located in said third conduit said inlet valve means located in said sixth conduit is positively openedL and said outlet valve means in said seventh conduit is closed and hydraulicv pressure is supplied to said auxiliary hydraulic;-

motor, said valve control means operable to positivelyolose said inlet valve means located in said sixth conduit :and open said outlet valve in said seventh conduit to bleed pressure from said auxiliary hydraulic motor.

13. An hydraulic system-comprising a'cylinder,

apistonreciprocable therein to lifta load when ihydraulic pressureis applied to said piston and to lowera load when hydraulic pressure is -bled from said cylinder, a pump, an engine for .op-

erating saidpump, inlet valve means including a spring loaded check valve, said inlet valve means operable to feedandnut off pressure from said pump -to said cylinder .and to prevent returnof pressure iromsaidzoylinder vto said pump, outlet valve means intermediate saidinlet valve means and saidoylinder operable to bleed pressure from said cylinder, and a single control means operable by movement in .one direction for throttling said engine and thereby controllingpumppreseure and while retaining a desired pump pressure operable by movement in another direction for closingsaid inlet valve andopening 16 or closing said outlet valve to bleed or retain pressure from or in said cylinder.

RAYMOND S. MILLER. GEORGE W. SINCLAIR.

References Cited in the file of this patent UNITED STATES PATENTS

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