US3664438A - Underwater rock core sampling device and method of use thereof - Google Patents

Abstract

A rotary diamond rock core drill capable of obtaining a threequarter inch diameter core four inches long at any depth down to 6,000 feet is provided. The drill is adapted to be used with manned deep submersibles and is operated by the submersible''s power supply. The drive motor is encased in an oil-filled, pressure-compensated chamber. A water pump in the drill maintains a steady low pressure flow of water against the sample during drilling operations, washing away rock chips and mud. The water flow may be reversed after the core has been cut, holding the specimen within the core tube as the drill is extracted from the rock outcrop. The sample is then ejected by again reversing the drive motor and pump, forcing the water flow down through the core tube and expelling the specimen.

Description

United States Patent Winget et al.

[54] UNDERWATER ROCK CORE SAMPLING DEVICE AND METHOD OF USE THEREOF [72] Inventors: Clifford L. Winget, Woods Hole; George W. Gibson, E. Falmouthi William S. Shultz, Cataumet, all of Mass.

[73] Assignee: The United States of America as represented by the Secretary of the Navy [22] Filed: Aug. 26, 1970 [21] Appl. No.: 66,935

[52] US. Cl ..175/6, 175/58, 175/330 [51] Int. Cl. ..E21b 3/10, E2 lb 7/12, E21b 49/02 [58] Field ofSearch... ..l75/6,58, 75,78,93, 103,

[ 51 May 23, 1972 Primary Examiner-Stephen J. Novosad Attorney-R. S. Sciascia, L. l. Shrago and C. E. Vautrain, Jr.

[ ABSTRACT A rotary diamond rock core drill capable of obtaining a threequarter inch diameter core four inches long at any depth down to 6,000 feet is provided. The drill is adapted to be used with manned deep submersibles and is operated by the submersibles power supply. The drive motor is encased in an oilfilled, pressure-compensated chamber. A water pump in the drill maintains a steady low pressure flow of water against the sample during drilling operations, washing away rock chips and mud. The water flow may be reversed after the core has been cut, holding the specimen within the core tube as the drill is extracted from the rock outcrop, The sample is then ejected by again reversing the drive motor and pump, forcing 10 Claims, 4 Drawing Figures PATENTED MAY 2 3 I972 sum 1 UF 3 PATENTEBMAY 23 I972 SHEET 2 OF 3 a/M/W/ z. 1% fear 6 M fllaon 1407/2/22 .5 5/71/47 UNDERWATER ROCK CORE SAMPLING DEVICE AND METHOD OF USE THEREOF The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This invention relates to bottom core samplers and, more particularly, to a rock core sampler for use with manned deep submersibles.

Previous methods of and means for obtaining hard rock specimens from the deep ocean have been operated from a floating vessel or a dredge, the' sample collector being towed along the bottom by the surface vessel. It is obvious that the precise location of the sample is not ascertainable by these methods. With the advent of manned deep submersibles, it became possible to pick samples off the bottom instead of the blind recovery previously practiced. The source of the sample thus obtained, however, still cannot be definitely ascertained since the sample may have been transported appreciable distances by a variety of forces. To obtain samples from known locations using manned deep submersibles required the development of a device which could be controlledby per sonnel in the manned deep submersible. The present invention provides a drill which may be controlled by the mechanical manipulator hand of the deep submersible and also provides novel means for continuously removing loose material from the drill face, maintaining a sample in the drill during retrieval and ejecting the sample from the drill at any desired time.

Accordingly, it is an object of the present invention to provide a rock sampling device for use with manned deep diving submersibles.

Another object of this invention is to provide a rock sampling device which may be operated by personnel in and power from a manned deep submersible and may be controlled by conventional mechanical manipulator hands on the submersible.

A further object of the invention is to provide a rock sampling device which is capable of obtaining hard rock cores of substantially inch diameter and 4 inches long from ocean depths down to 6,000 feet using exiting control devices.

Other objects, advantages and novel features of the invention will become apparent from the following detailed description thereof when considered in conjunction with the accompanying drawings in which like numerals represent like parts throughout and wherein:

FIG. I is a schematic diagram showing the major components of the invention;

FIG. 2 is a sectional plan view of a component of the schematic embodiment shown in FIG. 1;

FIG. 3 is a longitudinal sectional view of a second embodiment of the invention; and

FIG. 4 is a schematic view of a third embodiment of theinvention being operated remotely from a manned deep submersible.

Referring to FIG. 1, there is shown the deep core drill 11 which includes a tubular shell 12 housing in longitudinal succession a DC motor 13, a gear reducer 14, a universal joint 15, a flexible impeller water pump 16 and the upper end of a hollow drill shaft 17. The foregoing components are interconnected and are disposed in separate compartments. These components are adapted for operation in either a clockwise or counterclockwise direction depending on the particular use. Motor 13 is disposed in a chamber 20 which is filled with a pressure compensating oil 21 having high dielectric characteristics. The oil occupies several compartments and is separated from the seawater by means of a free-floating piston 24 which is slidably mounted on a pump shaft 25. Drill shaft 17 is connected to shaft 25 and is provided with a port 26 at the upper end for admitting seawater, an enlarged cavity 27 which is open at its remote end to receive the core sample and an interconnecting passage 28. Drill shaft 17 is provided with a collar 29 at its remote end which collar is fitted with a plurality of diamond tips 30 for cutting into the bottom rock. Housing 12 is provided with an opening 33 for admitting seawater into a seawater chamber 34 below piston 24. Seawater enters pump 16 through an inlet 35 in chamber 34 and exits the pump through an outlet 36 into a plenum chamber 37 between the lower face of the pump and the bottom of housing 12. Drill shaft 17 is secured to pump 16 by conventional means, not shown, and rotates in a bearing 40 in the bottom end of housing 12. A T-handle 38 is provided for securing into a threaded opening 39 in theupper end of housing 12. The handle 38 used is selected to mate with a submersible manipulator hand, the handle having a T-bar 40 for providing rotary control and a shaft 41 for providing longitudinal control.

FIG. 2 shows pump 16in transverse view, the pump including a casing 42 within which impellers 43 rotate, and a ramp '44 which substantially deforms the impeller arms so as to apply a sufficient pressure to force water through outlet 36.

In'the embodiment of FIG. 3, T-handle 50 is mounted in an end cap 51 which is secured to an outer drill housing 52. An inner drill housing 53 contains a drive mechanism 54, a universal joint 55, a pump assembly 56 and an end fitting 57 which has a flange 58 extending a sufficient distance outward to provide an abutting surface to receive a shock absorbing spring 59. Outer housing 52 slides over inner housing 53 on a plurality of nylon slide buttons 63 which are secured in outer housing 52. Electrical power supply lines 64 are received through an attachment 64 to inner housing 53. The power lines are removably connected by means of a connector 67. Drive mechanism 54 is contained in a chamber 68 which is filled with a pressure-compensating oil 69 as in the embodiment of FIG. 1. The pressure-compensating oil is admitted through dividers 70, 71 and 72 into a chamber 73 which is positioned above a diaphragm 74 whose transverse surface is disposed between a flange 75 and a clamp plate 76. Diaphragm 74 encloses a water chamber 77 by means of which seawater pressure is applied to compensating oil 69 to maintain the entire device under equal pressure. Water is admitted into chamber 77 by passage 78, into pump 56 by passage 79. Water is discharged from pump 56 through a connecting port 80 and into a hollow drill shaft 81 which is secured to pump 56 and traverses a bushing 82 which is disposed in end cap 57. Drill shaft 81 is provided with a core receiving chamber 83, water entering chamber 83 through a port 26 and a passage 84 in the upper portion of shaft 81. Flange 75 is mounted on a drive shaft 85 and is secured to the pump housing by a spring 86. A grease fitting 8 also is provided.

FIG. 4 illustrates another embodiment of the invention secured in a mechanical hand manipulator 91 which is connected to an arm 92 extending from the submersible hull. The

-core sampler 90 is substantially identical in internal components to the embodiment of FIG. 3; however, the outer casing has been replaced by a pair of spring restraining members 94 and 95, and a shock absorbing spring 96 is disposed between members 94 and 95.

In operation, the rock core drill is secured in the manipulator hand as indicated in FIG. 4, and the drill shaft 97 is disposed at an angle of 50 to 60 to the rock surface to enable a starting cut to be made. In the manipulator shown, the bar of the T-handle is nested into a notched section at the base plate of the fingers with the fingers grasping the handle shaft. The drill is operated at the angle indicated until a slight moonshaped groove is cut in the rock. The groove need not exceed one-sixteenth to one-eighth of an inch in depth; and, after this depth is reached, the assembly is slowly brought to a vertical position and the cut continued until the required core length has been reached. If the drill is not initially positioned at an angle, it will wander off from the initial point and be extremely difficult if not impossible to start the drilling action.

At the proper depth of penetration, the direction of the motor rotation is reversed, reversing the pump impeller and, consequently, the direction of water flow. Drilling action continues with the drill rotating in the opposite direction, but the mud now is not flushed out and instead begins to thicken at the base of the core hole. The drill assembly at this time preferably is rocked slightly to assist in seizing and breaking off the core specimen. The specimen is retained in the hollow core of the diamond drill by the slight suction maintained by the reverse water flow action of the impeller pump. The core drill next is removed from the hole and the rock core is deposited in a receptacle by again reversing motor rotation which reverses water pump flow, ejecting the rock core from cavity 27 of drill shaft 17. Additional hard rock cores may be obtained at once by repeating the drilling procedure.

Deep water operation of the drill has indicated that a restraining torque on the order of 23 in. lb. is suflicient in a selected vehicle to counteract the torque generated by the motor. Larger rotary drills or side wall sampling while the vehicle hovers at the side of a vertical outcrop will probably require the use of a holding dew'ce such as a suction pod or a driven piton.

The embodiment in FIG. 3 is the preferred embodiment of the invention and includes the two housings 52 and 53 which preferably are made of aluminum and are protected from both abrasion and corrosion through the use of an electrochemical coating of aluminum oxide. When T-handle 50 is depressed by the operator, the stainless steel compression spring 59 provides a constant 30-pound downward thrust on the drill bit. The constant load assures the operator of optimum bit per formance throughout the drilling cycle and tends to smooth out any spasmodic motion of the mechanical manipulator. The linear travel of the constant load spring is three inches.

Both the power cord and the motor/gear box assembly are fully pressure compensated. The oil reservoir is located within the drill housing and has sufficient capacity to assure complete compensation of the power cord. Without compensation, the power cord becomes still and unmanageable when exposed to the elevated hydrostatic pressures encountered at the operational depths of the vehicle.

Twisting between inner housing 53 and outer housing 52 is prevented by a connector housing, not shown, which is secured to the inner housing and free to slide within a slotted guide machined in the side wall of the outer housing. The assembly permits straight line motion as constant load spring 59 is depressed, while preventing rotary motion as a result of motor torque.

Grease fitting 87 in end cap 57 provides lubrication for thrust bushing 82 as well as furnishing a means of flushing the bearing surfaces with a lightweight grease.

When drilling under water, pump fluid flow is discharged into plenum chamber 37 through port 26 in hollow drill shaft 81. When in the drilling perpendicular mode, water flow is reasonably clean and free of sediment. On breaking off the core and reversing pump flow, mud and sediment is sucked up into the plenum chamber and out through the pump discharge. To assure that the mud residue does not penetrate the shaft seal and enter the bearing assembly, a shot of grease preferably is injected into the bearing at the completion of each dive. To facilitate the flushing procedure, cup seals, not shown, located at a clamp ring 90 and the base of drill shaft 81, are inserted to provide free flow out of the bearing area when grease is injected through fitting 87. Such shaft seals assure against rupture or blowout when grease is injected.

Diaphragm 74 is shown in the fully extended or empty position. Under normal conditions, the oil cavity is pressure filled, compressing spring 86 and collapsing the bellows into an accordion-pleated configuration. The total volume of oil contained within the drill in this embodiment is substantially 760 cc.

The air weight of the assembly of FIG. 3, including compensation oil and coiled power lead, is 13.6 pounds. Its water weight is 9.7 pounds.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. For example, means could be provided for marking the magnetic orientation on the core specimen prior to its removal from the parent material.

What is claimed is:

1. A hard rock corer for obtaining rock samples at depths down to 6,000 feet comprising:

a closed tubular housing having a handle secured thereto in sealed relationship at one end and receiving in sealed relationship a hollow drill shaft at the other end, said housing compartmented to receive in succession in individual interconnected chambers an electric motor, a reducing gear, a universal joint and a piston;

said chambers sealed at said piston from the environment and containing a pressure-compensating oil having selected dielectric characteristics for electrically insulating the device from the environment;

a drive shaft extending from said universal joint and connected in succession to a rotary water pump and said hollow drill shaft,

said piston slidably mounted on said drive shaft in sealing engagement therewith and with the interior surface of said tubular housing to separate the oil on one side thereof from water at ambient pressure on the other side;

an opening in said shell intermediate said piston and said pump for admitting water under ambient pressure to the portion of said piston chamber remote from said oil;

a pump inlet disposed in said piston chamber and a pump outlet disposed in an end chamber intermediate said pump and said other end of said housing;

said drill shaft having an opening in said end chamber and a core receptacle at its remote end, a passage connecting said opening and said receptacle;

a hard rock core drill secured to the remote end of said drill shaft; and

an electric power supply externally disposed with respect to said housing and means connecting said power supply and said electric motor, whereby during drilling said pump will direct water past the cutting bits, flushing away loose pieces and mud, and during retrieval the core sample will be held in said receptacle by the suction created by reversing said electric motor.

2. The corer as defined in claim 1 wherein said pump includes a plurality of resilient impellers and a ramp for stressing said impellers prior to discharging water through said outlet.

3. The corer as defined in claim 2 and further including a plenum disposed between said pump and the adjacent end of said housing,

said pump during drilling discharging water into said plenum, and

said opening in said drill shaft centrally disposed in said plenum.

4. The corer as defined in claim 3 wherein said handle is provided with a T-bar at its outer end for mating with a mechanical manipulator hand.

5. Means for obtaining rock core samples at extreme depths by an electrically powered rotary diamond tip core drill comprising:

a housing compartmented to accommodate in longitudinal succession an electric motor, drive means connected to said motor by a drive shaft, a rotary pump and a plenum; the compartments containing said motor and said drive means made watertight and containing a pressure-compensating oil having high dielectric characteristics;

said drive shaft traversing said pump and connected to a drill shaft;

a free-floating piston slidably mounted on said drive shaft, said piston exposed on its surfaces adjacent said pump compartment to the water environment through an opening in said housing and on its opposing surfaces to said pressure-compensatin g oil, said pump having an inlet disposed adjacent said housing opening and an outlet disposed in a plenum intermediate said pump and the adjacent end of said housing; and

said drive shaft having a core receiving receptacle adjacent a diamond tip core drill and a passage communicating between said receptacle and said plenum, whereby a lightweight drill having all components exposed to ambient pressure is provided wherein mud and particles are flushed away during drilling and a core sample is held by suction created by reversing said pump until the sample is recovered.

6. The device as defined in claim 5 and further including a handle secured to said housing remote from said drill and having a crossbar at its remote end for mating with mechanical manipulator means.

7. The device as defined in claim 6 wherein said pump is provided with a rubber impeller having a plurality of impeller arms.

8. The device as defined in claim 7 wherein said pump is further provided with a ramp for stressing said impeller arms prior to discharging water into said plenum.

9. The method of obtaining a rock core sample from extreme depths by an electrically driven rock core drill comprising the steps of:

surrounding the electric motor of said drill with a sealed pressure-compensating oil having suitable dielectric characteristics;

admitting seawater at ambient pressure into a free-flooding cavity adjacent the motor cavity;

applying water at ambient pressure to said pressure-compensating oil through a free-floating piston forming a portion of said cavity;

pumping water from said free-flooding cavity through a ho]- low drill shaft to a core receiving receptacle at the end of the drill shaft to flush away mud and particles during drilling; and

reverse pumping water from said receptacle to said freeflooding cavity after a core sample has been broken free to hold the sample by suction in the receptacle until the sample has been recovered.

10. The method as defined in claim 9 and further including the step of controlling the operation of said rock core drill by a mechanical manipulator.

Claims (10)

1. A hard rock corer for obtaining rock samples at depths down to 6,000 feet comprising: a closed tubular housing having a handle secured thereto in sealed relationship at one end and receiving in sealed relationship a hollow drill shaft at the other end, said housing compartmented to receive in succession in individual interconnected chambers an electric motor, a reducing gear, a universal joint and a piston; said chambers sealed at said piston from the environment and containing a pressure-compensating oil having selected dielectric characteristics for electrically insulating the device from the environment; a drive shaft extending from said universal joint and connected in succession to a rotary water pump and said hollow drill shaft, said piston slidably mounted on said drive shaft in sealing engagement therewith and with the interior surface of said tubular housing to separate the oil on one side thereof from water at ambient pressure on the other side; an opening in said shell intermediate said piston and said pump for admitting water under ambient pressure to the portion of said piston chamber remote from said oil; a pump inlet disposed in said piston chamber and a pump outlet disposed in an end chamber intermediate said pump and said other end of said housing; said drill shaft having an opening in said end chamber and a core receptacle at its remote end, a passage connecting said opening and said receptacle; a hard rock core drill secured to the remote end of said drill shaft; and an electric power supply externally disposed with respect to said housing and means connecting said power supply and said electric motor, whereby during drilling said pump will direct water past the cutting bits, flushing away loose pieces and mud, and during retrieval the core sample will be held in said receptacle by the suction created by reversing said electric moTor.

2. The corer as defined in claim 1 wherein said pump includes a plurality of resilient impellers and a ramp for stressing said impellers prior to discharging water through said outlet.

3. The corer as defined in claim 2 and further including a plenum disposed between said pump and the adjacent end of said housing, said pump during drilling discharging water into said plenum, and said opening in said drill shaft centrally disposed in said plenum.

4. The corer as defined in claim 3 wherein said handle is provided with a T-bar at its outer end for mating with a mechanical manipulator hand.

5. Means for obtaining rock core samples at extreme depths by an electrically powered rotary diamond tip core drill comprising: a housing compartmented to accommodate in longitudinal succession an electric motor, drive means connected to said motor by a drive shaft, a rotary pump and a plenum; the compartments containing said motor and said drive means made watertight and containing a pressure-compensating oil having high dielectric characteristics; said drive shaft traversing said pump and connected to a drill shaft; a free-floating piston slidably mounted on said drive shaft, said piston exposed on its surfaces adjacent said pump compartment to the water environment through an opening in said housing and on its opposing surfaces to said pressure-compensating oil, said pump having an inlet disposed adjacent said housing opening and an outlet disposed in a plenum intermediate said pump and the adjacent end of said housing; and said drive shaft having a core receiving receptacle adjacent a diamond tip core drill and a passage communicating between said receptacle and said plenum, whereby a lightweight drill having all components exposed to ambient pressure is provided wherein mud and particles are flushed away during drilling and a core sample is held by suction created by reversing said pump until the sample is recovered.

6. The device as defined in claim 5 and further including a handle secured to said housing remote from said drill and having a crossbar at its remote end for mating with mechanical manipulator means.

7. The device as defined in claim 6 wherein said pump is provided with a rubber impeller having a plurality of impeller arms.

8. The device as defined in claim 7 wherein said pump is further provided with a ramp for stressing said impeller arms prior to discharging water into said plenum.

9. The method of obtaining a rock core sample from extreme depths by an electrically driven rock core drill comprising the steps of: surrounding the electric motor of said drill with a sealed pressure-compensating oil having suitable dielectric characteristics; admitting seawater at ambient pressure into a free-flooding cavity adjacent the motor cavity; applying water at ambient pressure to said pressure-compensating oil through a free-floating piston forming a portion of said cavity; pumping water from said free-flooding cavity through a hollow drill shaft to a core receiving receptacle at the end of the drill shaft to flush away mud and particles during drilling; and reverse pumping water from said receptacle to said free-flooding cavity after a core sample has been broken free to hold the sample by suction in the receptacle until the sample has been recovered.

10. The method as defined in claim 9 and further including the step of controlling the operation of said rock core drill by a mechanical manipulator.

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