US2117078A

US2117078A - Drilling control mechanism

Info

Publication number: US2117078A
Application number: US119752A
Authority: US
Inventors: Brauer Walter
Original assignee: Individual
Current assignee: Individual
Priority date: 1937-01-09
Filing date: 1937-01-09
Publication date: 1938-05-10
Anticipated expiration: 1955-05-10

Description

May 10, 1938. w. BRAUER 2,117,078

DRILLING CONTROL MECHANI SM gmc/Mw" WALTER BRAUER May 10, 1938. w. BRAUER 2,117,078

DRILLING. CONTROL MEGHAISM Filed Jan. 9, 1937 v 2 Sheets-Shet 2 P' 2. i H

WALTER RAUER.

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Patented May 10, 1938 UNITED STATES PATENT IA-'FICE 6 Claims.

The invention relates to a brake control mechanism where the brake governs the movement of a drum carrying a cable. f

In many instances and particularly in well drilling operations the drill bit is advanced due to its own weight while it is being suspended by a. block and tackle froma drum. A brake mechanism applied to the drum is usually controlled so as to pay out the cable as the drilling operation progresses. It is needless to say that if the cable is released too slowly the drilling operation will be slowed down, while on the other han l, if the cable is paid out too fast then too much weight will be permitted to rest upon the drill bit which causes unnecessary deflection of the' drill bit from the vertical. It is desirable, therefore, to pay out the cable so as to feed the drill bit in proportion to the weight or the strain on the cable due to the weight of the bit. The rate at which the drill bit penetrates the formation of course varies with the formation being encountered and the present mechanism has therefore been devised with a view of controlling the brake mechanism as a function of the weight i5 suspended by the cable so that the mechanism will operate automatically to maintain a substantially uniform weight on the cable which is suspending the drilling equipment.

It is one of the objects of the invention to provide an automatically operating mechanism for brakes which will function in proportion to the load on the brake.

Another object of the invention is to provide a uid pressure control mechanism wherein there is a continuous circulation of pressure fluid.

Another object of the invention is to provide a safety mechanism for fluid pressure operated brake devices so as to apply the brake in event the pressure in the system drops below a predetermined value.

Another object of the invention is to provide a diiierential pressure operated diaphragm in a drilling control mechanism so that a variable pressure due to a fluctuating load can be bal- 5 anced by a constant pressure in order to control the drilling operation.

Other and further objects of the invention will be readily apparent when the following description is considered in connection with the accompanying drawings, wherein: l

Fig. 1 is a side view of a derrick brake and control mechanism construction illustrating the various parts in section.

Fig. 2 is'a top plan view of the assembly by which the control is obtained; and illustrating the (Cl. Z55-19) fluid piping connection to the various parts of the device.

The invention ls being described in connection with well drilling equipment, but it is to lbe understood that it may be applied to various devices where a brake is to be operated as a function of the load being braked.

All of the equipment has been illustrated as being positioned upon the derrick floor 2 inside of the confines of the derrick legs 3. 'I'he drawworks assembly is illustrated generally at I and of course includes the drum 5 upon which the cable is reeled in order to effect the raising and i lowering of the drill stem which is shown at G asprojecting through the rotary table 1. It is of course understood that the rotary table is rotated by means of the pinion shaft and the sprocket 9, which is in turn driven by a chain from the sprocket i i of the drawworks l. The cable which supports the string of pipe and the drill bit in the well bore passes upwardly over the crown block in the top of the derrick and of course through the usual traveling block and thence down to the drum 5 of the drawworks.

The other end of the cable known as the dead line is seen at i4 in Fig. 1 and will be anchored l at i6 to the derrick floor.

In order to control the rotation of drum 5 the brake bands Il are applied to each end of tne drum and will be operated by the brake lever iB seen in both Figs. l and 2.

During the drilling operation the brake lever i8 will be manipulated to allow the weight of the drill bit and the drill .stem to unreel the cable from the drum 5, the brake being applied to retard the paying out of the cable so that an excessive amount of weight will not be applied to the drill bit, and to controlthe adjustment of the bit in accordance with the formation being encountered, the `rate of rotation of the bit, and various other circumstances which have a bearing upon the rate of drilling.

'I'he present invention islin the nature of an improvement over my prior Patent 1,779,656, granted October 28, 1930, wherein the general` combination of an automatic brake regulator for rotary drilling is. disclosed. The present improvement consists primarily in` providing suitable control mechanism for the fluid pressure so as to equalize the action of the parts and to avoid sharp fluctuations in the fluid pressure used to control the mechanism, as well as to apply circulating fluid pressure which can be more accurately controlled than the arrangement of the fluid pressure shown in my prior patent.

In order to provide a source of circulating fluid pressure a supply tank 20 has been shown in Fig. 2. Disposed in this tank is circulating pump 2| which may be operated by the drive wheel 22 from a connection 23 on the end of the rotary drive pinion shaft. While this arrangement has been shown, it is to be understood that the power for circulating the fluid pressure liquid 24 from the tank 20 may be provided from any suitable source. The pump 2| discharges into the pipe line 21 which passes into the control device 28 which is shown in section in Fig. 1. The pressure in this fluid circuit is maintained constant by the use of a suitable pressure control valve 25 which may as a practical matter comprise a suitable by-pass valve. In such event it is obvious that the volume of liquid pumped by circulating pump 2| will be sufcient to ll control chamber 66 at such rate that the desired change in braking will occur. The fluid from this pipe line 21 discharges into a chamber 30 in the housing 3| and beneath a diaphragm 32. 'Ihis pressure of course tends to raise the diaphragm 32 away some so as to move it out of contact with a seat 33 which is formed on a nipple 34 carried by the base 35 of the control mechanism. The diaphragm 32 normally closes the nipple 34 of the valve 33 so that there can be no flow of fluid from the chamber 30 into the outlet pipe 31 which is connected to the nipple 34. The movement of the diaphragm 32 is assisted by a spring 40 which bears against the partition 4| of the housing- 3|, this spring being adjustable by means of hand wheel 42, which is threaded on the stem 43, which is connected to the diaphragm 32. In other words, the diaphragm is loaded by the spring 40 in any desired amount of adjusting the hand wheel 42. The pressure through the line 21 and in the chamber 30 will assist the loading of spring 40 before the diaphragm 32 can move upwardly.

In order to control the movement of the diaphragm as a function of the load on the drilling cable a iluid pressure connection 45 leads into the chamber 46 in the housing 3| above the diaphragm 32 and this connection 45 leads to a cylinder 41 which carries a piston 48 which presses against the dead line I4 of the cable. A suitable roller 49 is connected to the piston 48. The cylinder 41 is carried by a bracket 5l) which is shown as clamped to the dead line so that a variable pressure on the cable will impart a variable pressure to the piston 48 so that the fluid pressure in the chamber 5| will reflect this variable pressure in the chamber 46 of the control mechanism.

It will be apparent that the diaphragm 32 is thus controlled by a differential pressure so that it is either balanced or unbalanced, depending upon the variable pressure in the chamber 46, it being understood that the spring 40 will be used to load the diaphragm, depending upon the number of times the cable is reeved through the traveling block and the crown block and upon the weight of the drill stern in the hole.

The operation of the brake lever I8 is effected by means of the link connection 62 which is in turn connected to the stem 63 which carries a pist0n 64 disposed in the pressure cylinder 65. It will be observed that the uid pressure from the outlet pipe 31 is directed into the pressure chamber 66 so that it tends to move the piston 64 down, wardly and in this manner apply the brake to the brake drlmi. This fluid pressure is admitted to the chamber 66 only when the constant pressure in the chamber 30 exceeds the variable pressure in the chamber 46.

It has been found in practice, however, that a constant pressure is subject to variation due to expansion and contraction of the piping and other equipment due to leakage and to various other circumstances which cannot bey accurately controlled; for this reason the circulating mechanism described above has been provided so that there is a constant pressure applied in the chamber 30 which is admitted periodically to the chamber 6C. In order to effect a complete circulation of the liquid the outlet 10 has been provided on the cylinder 65 and a suitable choke 1| is disposed in this discharge outlet 10. The handle 12 serves to adjust the choke so as to restrict or enlarge the volume of flow through the chamber 66. The outlet pipe 13 continues as seen in Fig. 2 and discharges into the supply tank 20.

It is thus apparent that choke 1| permits adjustment of the rate of flow of fluid from control chamber 66 such that when an increased braking is desired the rate of ow of fluid through valve 33 to control chamber 66 exceeds a discharge flow through choke 1|, and brake lever I8 is moved downwardly by piston 64. On the other hand, if a decrease in braking is desired the rate of ow of fluid from control chamber 66 exceeds that from valve 33 into the chamber whereby piston 64 will rise and braking will be decreased.

The safety feature has been provided in event there is breakage in any of the piping or a failure of the supply pump 2| by an arrangement of a pipe which is connected to the supply pipe 21 and carries a pressure gaugev 8|. This pipe leads to a diaphragm 82 which is carried by a cylinder 83 on the safety housing 84. A latch member 85 is connected to the diaphragm 82 and is normally pressed inwardly due to fluid pressure through the pipe 80 on the diaphragm 82. A spring 86 resists a predetermined amount of pressure applied to the diaphragm so that while the latch 85 normally remains in the position shown in Fig. 1, if the pressure drops below this predetermined amount then thel spring 96 will move the latch 85 to the left or to retracted position.

The latch 85 normally serves to support a plate 88 which is'connected by a chain 90 to the brake arm I8. A spring 9| normally urges the plate 88 downwardly to retain it against the latch 85. When the latch 85 is removed due to a reduction in pressure the spring 9| will exert a downward pull on the stem at 89 and of course on the brake arm I8 so as to set the brake. This prevents unnecessary and undesirable relation of the cable with the brake mechanism in event of difficulty with any of the control mechanism.

Broadly, the invention contemplates a control mechanism for brakes which will be uniform in its action and which will be operated as a function of the load being braked. j

What is claimed is:

1. A brake control for feeding the cable of a drilling rig comprising in combination with the brake of a liquid pressure mechanism to exert a pull thereon, means to transmit liquid pressure to said mechanism as a function of the force opposing said brake, and means to discharge theV liquid from said mechanism at a predetermined rate so as to damp thefluctuation of the pressure actuating said mechanism.

2. A brake control for feeding the cable of a drilling rig comprising in combination with the brake of a liquid pressure Amechanism to exert a pull thereon, means totransmit liquid pressure to said mechanism as a function of the force opposing said brake, means to discharge the liquid from said mechanism at a predetermined rate so as to damp the iluctuation of the pressure actuating said mechanism, and additional means to set said brake ln event of reduction of the operating liquid pressure below a predetermined value.

3. A control mechanism for drilling rig brakes where the rate of feeding the cable from the brake drum is dependent upon the load being carried which comprises the combination of a supply of liquid subject to a pressure which is a function of the load on the cable, a diaphragm subjected to such pressure, means to apply a constant pressure to said diaphragm in balancing the load pressure, `a valve operated by said diaphragm to release the constant pressure when the load pressure is overbalanced, and means to actuate said brake when the ow of pressure iiuid 'released by said valve exceeds a predetermined volume.

4. A control mechanism for drilling rig brakes where the rate of feeding the cable from the 'brake drum is dependent upon the load being carried which comprlsesthe combination of a supply of liquid subject to a pressure which is a function of the load on the cable, a diaphragm subjected to such pressure, means to apply a constant pressure to said diaphragm in balancing the load pressure, al valve operated by said diaphragm to release the constant pressure when the load pressure is overba'lanced, means to actuate said brake when the flow of pressure fluid released by said valve exceeds a predetermined volume, said last means including a choke.

5. A control mechanism for drilling rig brakes Where the rate of feeding the cable from the brake drum is dependent upon the load being carried which comprises the combination of a supply of liquid subject to a pressure which is a function of the load on the cable, a diaphragm subjected to such pressure. means to apply a constant pressure to said diaphragm in balancing the load pressure, a valve operated by said diaphragm 4to release the constant pressure when the load pressure is over-balanced, means to actuate said brake when the iiow of pressure uid released by said valve exceeds a predetermined volume, said last means including a choke, and additional means to actuate said brake if the constant pressure falls below a predetermined value.

- 6. In an automatically operable fluid pressure brake control mechanism a safety device to actuate the brake in event the operating pressure falls below a predetermined value including a mechanically operated member to apply the brake, and `fluid pressure latching means to release said member when the pressure falls below a predetermined value. y A

WALTER BRAUER.