Coring system including tensiometer and method of deciding accurate coring using the same

The present invention relates to a coring system and a determining method that can determine whether accurate coring was achieved. A coring system according to the present invention includes: a coring part with a core to be filled with an object to be cored; a driving unit controlling upward/downward movement of the coring part; a rope connecting the coring part with the driving unit; and a tensiometer measuring tension in the rope.

CROSS-REFERENCE TO RELATED APPLICATION

The application claims the benefit of Korean Patent Application No. 10-2013-0138970 filed on Nov. 15, 2013 and the entire contents of which are incorporated herein by reference.

BACKGROUND

1. Field of the Disclosure

The present invention relates to a coring system including a tensiometer and a method of determining accurate boring using the same.

2. Description of the Related Art

There have been developed many coring rigs for studying underground resources or observing the history and the environmental change of the earth.

Most coring rigs place a coring part with a core for carrying an object to be cored, on the bottom of the sea or the bottom of a river and then insert it into a sediment, using the gravity etc. When the coring part is inserted in the sediment, some of the sediment comes into the core, and a sample of the sediment is obtained by returning the coring part.

However, because the coring part is inserted deep in the bottom of the sea or the bottom of a river in most cases of coring, there is a problem in that it is difficult to know whether the coring part is inserted in a sediment while keeping vertical.

When a coring part is not vertically inserted in a sediment, there is a problem in that the position (depth) of the expected sample in the sediment and the position (depth) of the actually obtained sample in the sediment become different.

FIG. 1shows a case when a coring part is accurately inserted in a sediment while keeping vertical andFIG. 2shows a case when a coring part is inaccurately inserted at a angle in the bottom of the sea.

The same amount of samples of the sediment remains in the cores of the coring parts in both ofFIGS. 1 and 2. In those cases, however, the positions (depths) of the samples in the sediments are different and it causes an error in investigation of changes in composition to the depth of the sediment.

PRIOR ART DOCUMENT

Patent Document

SUMMARY

The present invention has been made in an effort to provide a coring system and a method that can accurately determine whether coring was accurately performed.

An aspect of the present invention provides a coring system including: a coring part with a core to be filled with an object to be cored; a driving unit controlling upward/downward movement of the coring part; a rope connecting the coring part with the driving unit; and a tensiometer measuring tension in the rope.

The coring system may further include a determining unit that determines whether accurate coring was achieved by the coring part on the basis of a measurement result by the tensiometer.

The determining unit may determine that accurate coring was achieved, when tension in returning of the coring part is a predetermined value or more.

The determining unit may determine whether accurate coring was achieved, by comparing the tension when the coring part is returned with the tension before/after the returning.

The determining unit may determine that accurate coring was achieved, when the tension in returning of the coring part is large by a predetermined level than the tension before/after the returning.

The coring system may further include a display unit that displays the measurement value by the tensiometer.

The coring system may further include coring pulleys disposed between the driving unit and the coring part and changing the arrangement direction of the rope to be vertical, in which the tensiometer measures tension in the rope, between the coring pulleys and the driving unit.

The coring system may further include a tension pulley between the tensiometer and the rope.

Another aspect of the present invention provides a method that determines whether accurate coring was achieved, in a coring system including: a coring part with a core to be filled with an object to be cored; a driving unit controlling upward/downward movement of the coring part; and a rope connecting the coring part with the driving unit. The method may include: measuring tension in the rope in coring; and determining whether coring was accurately performed by the coring part on the basis of the measurement result by the tensiometer.

The determining may include comparing the tension when the coring part is returned with the tension before/after coring.

The determining may further include determining that accurate coring was achieved, when the tension in returning of the coring part is larger by a predetermined level than the tension before/after coring.

The coring system may further include coring pulleys disposed between the driving unit and the coring part and changing the arrangement direction of the rope to be vertical, in which the measuring of tension may be to measure tension in the rope, between the coring pulleys and the driving unit.

The present invention provides a coring system and a determining method that can determine whether accurate coring was achieved.

DETAILED DESCRIPTION OF THE EMBODIMENT

The accompanying drawings are only examples for illustrating the spirit of the present invention in detail and the scope of the present invention is not limited thereto.

Although a type of coring part using a weight is exemplified in the following description, the coring part of the present invention may be used for a type using a piston or a box type of coring.

Further, although it is exemplified in the following description to core a sediment on the bottom of the sea, the present invention may be used for coring a sediment or other objects on the bottom of a river.

A coring system according to an embodiment of the present invention is described with reference toFIGS. 3 to 5.

A coring system1includes a coring part10, a driving unit20, a rope30, and a tensiometer51.

The coring part10and the driving unit20are connected through a rope30and the coring part10is moved up/down by operation of the driving unit20. The tensiometer51measures tension of the rope30.

The coring part10is composed of a weight and a coring rod12and a coring core13that is an empty space in which a sediment can be picked is formed in the coring rod12. The top of the weight11is connected to the rope30and the coring part10is moved up/down by operation of the driving unit20.

As the rope30is loosened after the coring part10is placed on the bottom of the sea, the coring rod12is inserted into a sediment by the weight of the weight11. A sample of the sediment is picked into the coring core13in the insertion.

The driving unit20may be implemented by an electric motor etc. and moves up/down the coring part10. When coring is controlled on a ship, the driving unit20is disposed on the ship. In detail, the driving unit20may be an electric winch.

The rope30connects the driving unit20with the coring part10and transmits the power from the driving unit20to the coring part10. The rope30may be any one as long as it is made of a material suitable for power transmission. For example, a natural substance rope, a synthetic resin rope, a metal wire, or a chain may be used.

The extension direction of the rope30is changed by two pulleys41and42. The extension direction of the rope30is changed vertically in the direction of gravity on the coring part10by the first pulley41and is changed too between the driving unit20and the first pulley41by the second pulley42. The first pulley41may be disposed at the end of a crane on a ship.

The second pulley42may not be provided in another embodiment and pulleys may be additionally used in another embodiment.

The tensiometer51measures tension in the rope30between the first pulley41and the second pulley42. The tension of the rope30changes with whether the driving unit20operates and with the position of the coring part10. For example, the tension is smaller when the coring part10is supported by buoyancy in water than when it is on water.

The tensiometer51is connected with the rope30through a tension pulley43in order not to interfere with movement of the rope30. A connector52is disposed between the tensiometer51and the tension pulley43. One end of the connector52is coupled to the tension pulley43and the other end is thread-fastened to the tensiometer51. The tensiometer51is held by a structure on a ship through a sub-rope31. A connector53is also disposed between the tensiometer51and the sub-rope31.

The tensiometer51can resist the tension range of the rope30, and any kind of tensiometer can be used as long as it can be connected with the tension pulley43and the sub-rope31, as inFIG. 3.

The data of tension measured by the tensiometer51is transmitted to a display unit61and a determining unit62by wire or wireless communication. The display unit61displays changes in tension, as coring proceeds (time passes), for the convenience of a user. Though not shown, a storing unit for storing the tension data may be provided.

The determining unit62determines whether coring was accurately performed on the basis of the data of measured tension. In detail, it can determine accurate coring on the basis of the magnitude of tension when the coring part10in the bottom of the sea is returned (pulled out from the bottom of the sea) or by comparing tension in other states.

When the tension in returning is a predetermined value or more in absolute value, it determines that accurate coring was achieved.

In determining by comparing, the tension A in returning may be compared with the tension B when the coring part10is above the sea or the tension B when the coring part10is in the sea. For example, when the tension A is large by a predetermined value (for example 200 kg, 500 kg etc.) than the tension B or is several times (for example, two times, five times, ten times etc.) the tension B or more, it determines that accurate coring was achieved. It can be determined in the same way, when the tension A is compared with the tension C.

The details of the predetermined value, predetermined level, or several times, which is the reference for the determination may be adjusted in accordance with the weight of the coring part10.

The reason that it is possible to determine whether accurate coring was achieved, from the absolute value of the tension A in returning or by comparing the tension A with another tension is as follows.

The largest tension is exerted in the rope62, when the driving unit20is operated to return the coring part10in the bottom of the sea in coring. However, the force for returning is dispersed, when coring is performed wrong, as inFIG. 2. Accordingly, the tension for returning inFIG. 2is smaller than that when coring is accurately performed, as inFIG. 1. Therefore, it is possible to determine whether coring was accurately performed, by observing the tension before/after returning.

A method of determining whether accurate coring was performed, using a change in tension is described hereafter with reference toFIGS. 6 and 7.FIG. 6shows test data when accurate coring was achieved, as inFIG. 1, andFIG. 7shows test data when coring was performed wrong, as inFIG. 2.

The section (a) is a period with the coring part10is in the sea, which tension of about 400 kg is maintained. The section (b) is a period when the coring part10is inserted in the bottom of the sea by its own weight, in which low level of tension is shown. A sediment comes into the coring core13in the section (b).

The section (c) is a period when the coring part10is moved up by the driving unit20winding the rope30after sampling of the sediment, in which the tension repeats increasing and decreasing. In the section (c), the tension when the coring part10is returned (pulled out) by the driving unit20that keeps winding the rope30is shown. The largest tension was over 100 kg. The tension in the section (d) is the largest in both of accurate coring and inaccurate coring.

Thereafter, in the section (e), the coring part10is in the sea. Though not shown, the coring part10is thereafter lifted out of the sea and a sample of the sediment is obtained.

When accurate coring is achieved, as inFIG. 6, the tension is the largest in the section (d) where the coring part10is pulled out, and is over two times the tension in the section (a) where the coring part10is in the sea. Further, changes in tension are distinct in the section (d) and the tension in the section (e) is similar to that in the section (a).

When accurate coring is achieved and the change pattern in tension ofFIG. 6is shown, it is possible to determine that it is accurate coring from whether the tension in the section (d) is over two times the tension of the section (a).

In contrast, when coring is performed wrong, as inFIG. 7, the tension when the coring part10is pulled out is not clear in comparison to that inFIG. 6and the tension value is under two times that in the section (a). InFIG. 7, it would be considered that the coring part10was pulled out of the sediment in the middle of coring.

As described above, according to the present invention, it is possible to determine whether coring was accurately performed, by measuring tension.

The embodiments described above are examples for describing the present invention and the present invention is not limited thereto. The present invention may be achieved in various ways by those skilled in the art and the scope of the present invention should be determined by claims.