US3412814A

US3412814A - Hydrostatic corer

Info

Publication number: US3412814A
Application number: US650164A
Authority: US
Inventors: Andre M Rosfelder
Original assignee: Usa
Current assignee: USA
Priority date: 1967-06-28
Filing date: 1967-06-28
Publication date: 1968-11-26
Anticipated expiration: 1985-11-26

Description

Nov. 26, 1968 A. M. ROSFELDER 3,412,814

' HYDROSTATIC CORER Filed June 28, 1967 2 Sheets-Sheet 1 Fig.

I fF a- Z INVENTOR. ANDRE M. ROSFELDER ERVl/V E JOHNSTON Y A TTOR/VEY Nov. 26, 1968 A. M. ROSFELDER HYDROSTATIC CORER 5220 & 16Gb 2 Sheets-Sheet 2 Filed June 28, 1967 Why 17/ United States atent O 3,412,814 HYDROSTATIC CORER Andre M. Rosfelder, La Jolla, Calif., assignor, by mesne assignments, to the United States of America Filed June 28, 1967, Ser. No. 650,164- Claims. (Cl. 1756) ABSTRACT OF THE DISCLOSURE The present invention relates to a hydrostatic corer which may be used for obtaining core samples from the bottom of a body of water such as the ocean. The corer includes a coring barrel which at a selected time is powered by hydrostatic pressure within the body of water. The hydrostatic motive force is obtained by providing a vacuum chamber within the coring barrel, this vacuum chamber normally being at atmospheric pressure. A pair of pistons seal the top and bottom of the vacuum chamber, the top piston being adapted to drive the coring barrel into the water bottom and the bottom piston being adapted to remain stationary on the water bottom and undergoing piston action within the coring barrel during the barrels penetration. Stability of the hydrostatic corer is accomplished by a skirt at the bottom of the corer which is subjected to a vacuum to draw it tight against the water bottom prior to penetration of the coring barrel.

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.

The taking of core samples from the bottom of the ocean serves many purposes, such as enabling strength determinations prior to erection of bottom located structures; enabling reflective characteristics for predicting sonar responses; and providing indication of the presence of minerals for mining purposes. Mans interest in these fields has been steadily increasing, thus requiring a corresponding increase in the demand for ocean bottom data. Extensive exploration of the continental shelves has been taken, thus requiring improvements in the coring art, which art has been dormant for a number of years.

An important step forward in the coring act was the use of hydrostatic pressure as the motive force for driving a coring barrel into the ocean bottom. The basic concept on this approach is attributable to Varney and Redwine who disclosed their concept in US. Patent No. 2,176,477. Seveveral coring devices have been patterned after the Varney and Redwine concept and have been successful for their intended purposes. These coring devices have been somewhat cumbersome, however, and have required heavy material handling equipment for their implacement on the ocean bottom. The demand now is for a hydrostatic corer which is more compact so that more core samples can be obtained for the same amount of material handling time.

The present invention has accomplished this purpose by providing a vacuum chamber within the coring barrel itself. Heretofore, the volume within the coring barrel has been wasted space and has resulted in a corer which is larger than it need be for accomplishing the same purposes as the present invention. In one embodiment of the invention a vacuum tube is disposed within the coring barrel for providing the vacuum chamber and in another embodiment of the invention the coring barrel itself provides the vacuum chamber. When the hydrostatic corer comes to rest on the ocean bottom the vacuum chamber is subjected to atmospheric pressure or less while the area outside the vacuum chamber is subjected to hydrostatic pressure. A pair of pistons may be employed for utilizing this potential power to drive the coring barrel into the ocean bottom.

'ice

Another feature of the present invention, as illustrated in one of its embodiments, has been the provision of stability of the hydrostatic corer while the coring barrel is undergoing penetration. This has been accomplished by providing the bottom of the hydrostatic corer with a skirt along with means for evacuating the bottom of the skirt so as to retain the hydrostatic corer tightly against the bottom during the penetration period.

An object of the present invention is to provide a more compact hydrostatic corer.

Another object is to provide a hydrostatic corer which is easier to handle both prior to and after disposition in a body of water.

A further object is to provide a compact hydrostatic corer which has increased stability on the ocean bottom during penertation of the coring barrel.

Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings wherein:

FIG. 1 is a side view of one embodiment of the invention shown partially in longitudinal cross section and prior to penetration of the coring barrel into the ocean bottom;

FIG. 2 is the same view as shown in FIG. 1 except the hydrostatic corer has been actuated and the coring barrel has penetrated the ocean bottom;

FIG. 3 is a detailed longitudinal cross sectional view of the embodiment shown in FIGS. 1 and 2; and

FIG. 4 is an isometric view of another embodiment of the invention shown partially in cross section.

Referring now to the drawings wherein like reference numerals designate like or similar parts throughout the several views, there is shown in FIGS. 1 through 3 one embodiment of the invention. There is shown a coring barrel 10 and means for providing a vacuum chamber 12 which is located within and extends along the coring barrel. In this particular embodiment the means providing the vacuum chamber includes a vacuum tube 14 and a pair of

pistons

16 and 18.

The vacuum tube 14 is located within the coring barrel 10 and may be aligned concentrically therewith. The piston 16 is connected to the bottom of the vacuum tube 14 so as to seal the bottom of the vacuum chamber 12 and is mounted within the coring barrel 10 for piston action along the inner wall thereof. The piston 16 is adapted to remain substantially stationary on the ocean bottom as the coring barrel 1t) penetrates the ocean bottom and will accordingly hereinafter be referred to as the stationary piston. The piston 18 is fixedly mounted at the top of the coring barrel 10 by means which will be explained hereinafter and is mounted within the vacuum tube 14 for piston action therein thereby sealing the top of the vacuum chamber 12. This piston is connected to the coring barrel 10 and is in communication with the outside ocean pressure environment so that upon its release the differential in pressure between the ocean environment and the vacuum chamber the coring barrel 10 will be driven into the ocean bottom. Because of its driving action the piston 18 will hereinafter be referred to as the driving piston.

The means mounted the driving piston 18 at the top of the coring barrel 10 may include several components. First, a piston rod 20 may be connected to the top of the driving piston 18 and may extend upwardly therefrom. A driving head 22 may be connected to the top of the piston rod 20 and at the outer extremeties of the driving head there may be elongated means such as rods 24 which rigidly connect the driving head 22 to the top of the coring barrel 10. Accordingly, the top of the driving head 22 is exposed to the outside hydrostatic pressure environment while the bottom side of the driving piston 18 will be subjected to the low pressure within the vacuum chamber 12.

This potential power is then usable for driving the coring barrel into the bottom of the ocean.

It is desirable that the hydro-static corer be provided with a support means other than the stationary piston 16 when the core comes to rest on the bottom of the ocean. This support means may include a transverse element 26 which is connected at the top of the vacuum tube 14. A skirt 28 may be provided at the bottom of the coring barrel 10 and the skirt 28 may be rigidly connected to the transverse element 26 by a series of rods or slender tubes 30. A wide diameter skirt 28 provides lateral stability for the hydrostatic corer when it comes to rest upon the ocean bottom. As shown in the figures the skirt 28 may be substantially co-planar with the stationary piston 16. Weights 32 may be disposed on the top of the skirt 28 for preventing recoil of the hydrostatic corer upon penetration of the coring barrel 10 into the ocean bottom.

As shown in FIGS. 1 through 3, the hydrostatic corer may be lowered into the ocean by a cable 34 which is laced through a bail 36, the bail 36 in turn being connected to a lowering cable 38 from a surface vehicle (not shown). The bottom ends of the cable 34 may be connected to the piston rod through a latch means 40 which will be described in detail in the following paragraph.

In FIG. 1 the driving piston 18 is shown in its upper retained position and in FIG. 2 the driving piston 18 has been released to cause the differential in pressure to drive the coring barrel 10 into the ocean bottom. This action is accomplished by a means 40 which retains the driving piston 18 at the top of the vacuum tube 14 and which releases the driving piston when penetration of the coring barrel is desired. The particular latch means, which is shown in detail in FIG. 3, may be held in its retaining position when the cable 34 is undergoing strain upon lowering the corer and may be released when this cable is slackened. As shown in FIG. 3, the latch means 40 may include a top annular plate 42 and a bottom annular plate 44 which are interconnected by a series of rods 46 (one being shown in the figure) and which both are slidable along the piston rod 20. Interposed between the

plates

42 and 44 may be a series of latches 48 (one of which is shown in the figure) which interlock with an annular groove 50 in the piston rod when the

plates

42 and 44 are in the up position as shown in FIG. 3 and pivot to release the piston rod 20 when the bottom plate 44 is lowered to free the bottom ends of the latches. The latches 48 may be pivoted by any suitable means such as the small frame assembly 52 which may be rigidly connected to the transverse support element 26. The top of this frame assembly may have an annular plate 52a for guiding longitudinal movement of the piston rod 20. The bottom ends of the cable 34 are connected to the top annular plate 42 so that upon lowering of the corer the latches 48 hold the piston rod 20 in a retained position and when the cable 34 is slackened the bottom annular plate 44 is lowered to release the latches 48 and the piston rod 20. This action releases the driving piston.

After the hydrostatic corer has obtained a bottom sample and has commenced its ascent toward the ocean surface it is to be noted that the small space between the driving piston 18 and the stationary piston 16, as seen in FIG. 2, will tend to expand thereby causing the driving piston to Withdraw from the vacuum tube 14 and push the bottom sample from the coring barrel 10. Accordingly, it is necessary that a means be provided for relieving the hydrostatic pressure within the small space between the pistons during ascent of the hydrostatic corer. Referring to FIG. 3, this has been accomplished by providing the driving piston 18 and the piston rod 20 with a central bore 54 which communicates the vacuum chamber 12 with the outside pressure environment. At the top of the piston rod 20 there is provided a oneway pressure relief valve 56 which will allow a higher pressure within the vacuum chamber to be relieved therefrom but not vice versa. The relief valve 56 may include a hollow plug 56a which is threaded into the top of the piston rod 20. The plug 56a has a central chamber 56b which communicates with the outside pressure environment through opening 560 and communicates with the vacuum chamber 12 through a bottom opening 56a. Disposed within the central chamber 56b is a ball 56e which is forced downwardly to seal with the opening 560. by a diverging compression spring 56) which is located between the top of the ball 56c and the top of the central chamber 56b. Accordingly, the outside hydrostatic pressure is not imposed upon the vacuum chamber 12 but when the pressure within the vacuum chamber becomes sutliciently greater than the outside pressure the ball 56a will move upwardly to relieve this pressure.

The details of the connections of the various components of the first embodiment have not been described in detail since they do not form a part of this invention and are very clearly illustrated in FIG. 3. While the driving head 22 and the transverse support element 26 are shown as plates it is to be understood that they may take different forms such as transverse elongated members. When plates are used it will be necessary to provide the driving head 22 with openings 22a for the passage of cable 34, and the transverse support element 26 with openings 26a for the passage of the longitudinal rods or tubes 24. The bottom edge of the cutting head of the coring barrel 10 is shown with a slanted configuration which has proven to facilitate penetration of the coring barrel into the ocean bottom. The operation of the first embodiment shown in FIGS. 1 through 3 will be described in detail after the following description of another embodiment shown in FIG. 4.

The embodiment shown in FIG. 4 is similar to the first described embodiment in that a vacuum chamber 58 is provided within a coring barrel 60. One essential difference is that the coring barrel 60 itself forms the vacuum chamber 58 rather than a vacuum tube 14 as used in the first embodiment. Like the FIG. 1 embodiment, a stationary piston 62 is mounted for piston action within the coring barrel 60 and seals the bottom of the vacuum chamber 58 and in the same manner a driving piston 64 seals the top of the vacuum chamber 58. The difference between the two embodiments is that the driving piston 64 is connected directly to the top of the coring barrel 60. Similar to the FIG. 1 embodiment, a skirt 66 is provided and is located substantially coplanar with the stationary piston 62. The remaining structure of the FIG. 4 embodiment varies considerably from the FIG. 1 embodiment. Connected to the top of the skirt 66 is an outer tube 68 which extends upwardly and concentrically about the coring barrel 60 beyond the top of the coring barrel. An upper portion of this outer tube forms an atmospheric chamber 70 and a lower portion of the outer tube forms a suction chamber 72. The suction chamber 72 is open to hydrostatic pressure at the bottom by a space 73 between the skirt 66 and the core barrel 60. This space may be of such a size to dampen the rate of barrel penetration by the resistance to water outflow from chamber 72.

The driving piston 64 is mounted for piston action within the outer tube 68 and is adapted to slide along a stationary hollow piston rod 74. The hollow piston rod 74 is open at its bottom into the vacuum chamber 58 and opens at its top into the atmospheric chamber 70 or the outside ocean environment through a three way valve assembly 76. The valve assembly opens at its top into chamber 58 and opens into the ocean environment through a tube 77 which may extend through the wall of the outer tube 68.

It can be visualized as the driving piston 64 undergoes downward movement within the outer tube 68 that the suction chamber 72 between the driving piston and the atmospheric chamber 70 will be subjected to a vacuum. This vacuum has been utilized in the present invention for evacuating the bottom of the skirt 66 and retaining the corer tightly against the ocean bottom to prevent recoil as the coring barrel 60 penetrates the ocean bottom. This vacuum is subjected within the skirt 66 by a series of conduits 78 which extend between the upper portion of the suction chamber 72 and the interior of the skirt 66.

The chamber 70 will normally be at atmospheric pressure which is obtained while the corer is at the surface out the water and prior to its descent therein. During descent the vacuum chamber 58 is closed to chamber 70 and is open to hydrostatic pressure by the valve 76. After the corer comes to rest on the ocean bottom the lower pressure within chamber 70 is introduced into the vacuum chamber 58 by the actuation of the valve 76. This valve actuation may be accomplished by any suitable means such as a valve controller 80 which is shown mounted on the exterior of the outer tube 68. The valve controller 80 may be powered by a battery pack 82 which may be mounted to theexterior of the outer tube 68. The controller 80 may be energized by a mercury switch 84 which is mounted to a lowering cable 86 and which will close when the cable 86 is slackened to form a catenary. Such a switch is well known in the art.

In order to relieve the vacuum in the suction chamber 72 above the driving piston 64 after the skirt 66 has been sufiiciently drawn against the ocean bottom, a relief valve 88 may be provided in the wall of the outer tube 68. This relief valve may be similar to the relief valve 56 of the first embodiment except it would normally have a stronger compression spring. In order to relieve the higher pressure within the vacuum chamber 58 after actuation of the driving piston 64 and ascent of the corer, a relief valve 90 may be provided in the upper portion of the outer tube 68 within the atmospheric chamber 70. This relief valve 90 may also be similar to the relief valve 56 described for the first embodiment.

In the operation of the embodiment shown in FIGS. 1 through 3 the corer is placed in the ocean by a surface vehicle (not shown) with the driving piston 18 in the upward position as shown in FIG. 1. In this position the vacuum chamber 12 is under atmospheric pressure. The corer is then brought to rest on the ocean bottom at a desired location, as shown in FIG. 1, and the cable 38 is slackened so as to operate the latch means 40 and release the piston rod 20.

This release frees the driving piston 18 so that hydrostatic pressure forces the driving piston 18 downwardly within the vacuum tube 14. This downward movement of the driving piston 18 subjects the coring barrel to a downward force through the driving head 22 causing the coring barrel to penetrate the ocean bottom, as shown in FIG. 2. A strain may then be taken on the cable 38 to withdraw the coring barrel from the ocean bottom and upon ascent the relief valve 56, as shown in FIG. 3, will relieve the now high pressure between the two pistons.

In the operation of the embodiment shown in FIG. 4 the corer is placed in the water with the chamber 70 at atmospheric pressure. At this time the valve 76 is in a first position which opens the vacuum chamber 58 to the outside sea environment. When the corer comes to rest at a desired location on the ocean bottom the cable 86 is slackened and the switch 84 will actuate the controller 80 and cause the valve 76 to close the vacuum chamber 58 to the seal environment and open such chamber to the atmospheric chamber 70. The bottom of the piston 64 within the vacuum chamber 58 is now subjected to atmospheric pressure and the top of the piston is subjected to hydrostatic pressure through the conduits 78. This differential in pressure between the top and bottom of the driv ing piston forces the piston downwardly, thus driving the coring barrel 60 into the ocean bottom. The downward movement of the driving piston 64 causes a vacuum in the suction chamber 72. just above the driving piston, which vacuum is transmitted via the conduits 78 to the skirt 66 so as to draw the skirt tightly against the ocean bottom. This latter action prevents recoil of the corer while the coring barrel 60 is penetrating the ocean bottom. If this vacuum becomes too great the relief valve 88 will come into operation. After the core sample has been obtained and during ascent of the corer the now hydrostatic pressure within the vacuum chamber 58 between the two pistons is relieved by the relief valve 90.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

I claim:

1. A hydrostatic corer comprising:

a coring barrel;

means providing a vacuum chamber which is within and extends along said coring barrel, said means including:

a stationary piston means sealing the bottom of the vacuum chamber and movably mounted within the coring barrel for piston action along the inner wall thereof, said piston means being adapted to remain substantially stationary on the ocean bottom as the coring barrel penetrates the ocean bottom; and

a driving piston means sealing the top of the vacuum chamber and communicable with the ocean pressure environment and fixedly mounted at the top of the coring barrel for driving the coring barrel into the ocean bottom when a differential in pressure exists between the ocean environment and said vacuum chamber;

means for retaining the driving piston at the top of the vacuum chamber and releasing the driving piston when penetration of the coring barrel into the ocean bottom is desired.

2. A hydrostatic corer as claimed in claim 1 including:

a skirt; and

means mounting the skirt to the stationary piston means with the skirt substantially co-planar therewith.

3. A hydrostatic corer as claimed in claim 2 including:

means for evacuating the bottom of the skirt so that the skirt will be drawn tight against the ocean bottom.

4. A hydrostatic corer as claimed in claim 1 including:

means for relieving pressure within said vacuum chamber upon ascent of the hydrostatic corer, the pressure relieving means comprising:

a hollow piston rod connected to the top of the driving piston and extending upwardly therefrom; and

a relief valve connected at the top of said piston rod.

5. A hydrostatic corer as claimed in claim 1 wherein:

the means providing the vacuum chamber includes a vacuum tube mounted concentrically within said coring barrel.

6. A hydrostatic corer .as claimed in claim 5 wherein and including:

said driving piston means being slidably mounted in said vacuum tube;

a transverse element mounted at the top of the vacuum tube;

a piston rod connected to the driving piston and extending upwardly through said transverse element;

a driving head connected to the top of the piston rod;

and

elongated means rigidly connecting the driving head to the top of the coring barrel.

7. A hydrostatic corer as claimed in claim 6 including:

said transverse element extending transversely from the vacuum tube beyond said coring barrel;

said elongated means extending through the transverse element extension;

a skirt disposed substantially co-planar with said stationary piston means; and

means connecting the transverse element extension to said skirt.

8. A hydrostatic corer as claimed in claim 7 wherein and including:

the retaining and releasing means includes a latch means, connected to the transverse element, for fixedly engaging and releasing said piston rod; and

cable means connected to the latch means for fixedly engaging the latch means with the piston rod when the cable is under strain and releasing the latch means from the piston rod when the cable is slackened.

9. A hydrostatic corer as claimed in claim 3 wherein:

the coring barrel forms said vacuum chamber.

10. A hydrostatic corer as claimed in claim 9 wherein and including:

an outer tube connected to said skirt and extending up wardly concentrically about the coring barrel, said outer tube forming a suction chamber and extending upwardly beyond the top of the coring barrel to form an atmospheric chamber;

the driving piston being fixedly connected to the top of the coring barrel and mounted in the suction chamber of the outer tube for piston action therein;

a hollow piston rod extending from the atmospheric chamber of the outer tube through the driving piston, and into the coring barrel;

conduit means extending from a top portion of said suction chamber to said skirt; and

valve means for opening and closing said atmospheric chamber to the coring barrel through said hollow piston.

References Cited UNITED STATES PATENTS 2,176,477 10/1939 Varney et al. 175-6 2,664,269 12/ 1953 Knight et al 175-20 3,225,602 12/1965 Barton 73-4252 3,266,323 8/ 1966 Buchanan et a1 73-425 .4 3,299,969 1/ 1967 Inderbitzen 175-5 NILE C. BYERS, JR., Primary Examiner.