Bionic self-closing retainer for a sampling tube

Abstract

A kind of bionic self-closing stopper for sampling tube belongs to the field of geological engineering columnar sampling, including stop ring, petal-shaped elastic sheet, water-sensitive driving sheet, fixed screw and rivet, petal-shaped elastic sheet is evenly fixed in the inside of stop ring in annular form by fixed screw, one end of water-sensitive driving sheet is fixedly connected with petal-shaped elastic sheet by rivet, the other end is connected in the inner wall of stop ring by fixed screw;Water-sensitive driving sheet is in shrinkage state when dry to drive petal-shaped elastic sheet to adhere to stop ring;After water absorption, water-sensitive driving sheet gradually expands to push petal-shaped elastic sheet to bend and close to the central axis direction of stop ring.The present application drives petal-shaped elastic sheet to open and close by water-sensitive driving sheet, before sampler enters stratum, water-sensitive driving sheet is in dry state, at this time, sample can pass through stopper and enter sampling tube smoothly, after obtaining sample, water-sensitive driving sheet is gradually affected by formation water, expands and deforms to drive petal-shaped elastic sheet to close, and sample in sampling tube will not fall off during lifting process.

Description

Technical Field

[0001] This invention belongs to the field of columnar sampling in geological engineering, specifically a biomimetic self-closing stopper for sampling tubes. Background Technology

[0002] Seabed and lakebed surface sediments and soils are characterized by low strength and high plasticity. During sampling, samples in the sampling tube are prone to complete detachment or partial loss, affecting the sample acquisition rate and hindering geological data acquisition and engineering geological assessment. Installing claw springs at the bottom of the sampling tube can prevent sample detachment. While ordinary conical claw springs can prevent sample detachment to some extent, they still cause significant disturbance to the sample, specifically manifested in the following ways:

[0003] (1) The spring of the snap ring has a large stiffness. When the sedimentary stratum sample enters the sampling tube, it is subjected to a large resistance. This resistance will affect the sample acquisition rate on the one hand, and will also cause sample compression on the other hand.

[0004] (2) When the sample enters the sampling tube, the snap ring will scratch the sample. For soft sediments, the surface structure of the sample entering the sampling tube is damaged, and even creep flow may occur, and the sample sequence structure is completely destroyed. Summary of the Invention

[0005] To address the challenge of sampling disturbance in unconsolidated sediments in the aforementioned sedimentary layers, the purpose of this invention is to propose a self-closing anti-reverse device, using pine cone scales as a biomimetic prototype and mimicking the self-closing characteristics of pine cones. Pine cone scales are primarily composed of lignin. Lignin swells after absorbing water. Due to the different distribution of lignin in the inner and outer layers of the pine cone, the degree of swelling after water absorption differs, thus exhibiting the phenomenon of "opening when dry and closing when wet."

[0006] The technical solution adopted by the present invention to achieve the above objectives is as follows: a biomimetic self-closing stopper for sampling tubes, comprising a stop ring, a petal-shaped spring, a water-sensitive driving plate, a fixing screw, and a rivet. The stop ring is a hollow cylinder with a top hole and a bottom hole respectively in the upper and lower parts. The stop ring has an upper thread and a lower thread. The stop ring is connected to the sampling tube through the upper thread and to the tube shoe through the lower thread. The petal-shaped spring is uniformly fixed in a ring shape to the inner side of the stop ring by the fixing screw. When the stopper is open, the petal-shaped spring is tightly attached to the inner wall of the stop ring. When the stopper is closed, the petal-shaped spring bends and closes towards the central axis of the stop ring. One end of the water-sensitive driving plate is fixedly connected to the petal-shaped spring by the rivet, and the other end is connected to the inner wall of the stop ring by the fixing screw. When the water-sensitive driving plate is dry, it is in a contracted state, driving the petal-shaped spring to be tightly attached to the stop ring. After the water-sensitive driving plate absorbs water, it gradually expands, pushing the petal-shaped spring to bend and close towards the central axis of the stop ring.

[0007] Furthermore, the diameter of the top hole of the anti-reverse ring is 1mm to 2mm smaller than the diameter of the bottom hole.

[0008] Furthermore, the material of the water-sensitive drive sheet is vulcanized water-swellable rubber.

[0009] Furthermore, the structure of the water-sensitive driving plate is as follows: in the dry state, the water-sensitive driving plate is V-shaped, and under the connection of the rivets, it drives the petal-shaped spring to approach the anti-reverse ring, so that the anti-reverse device is in the open state; in the water-absorbing and swelling state, the water-sensitive driving plate is L-shaped, which drives the petal-shaped spring to deform, and the anti-reverse device is in the closed state.

[0010] Through the above design scheme, the present invention can bring the following beneficial effects: The present invention provides a biomimetic self-closing stop for sampling tubes, which mimics the function of pine cone scales closing when exposed to water. It uses a water-sensitive driving plate that expands when exposed to water to drive the opening and closing of the petal-shaped spring. Before the sampler enters the formation, the water-sensitive driving plate is in a dry state, and the petal-shaped spring connected to it is in an open state. At this time, the sample can smoothly enter the sampling tube through the stop. After the sample is obtained, the water-sensitive driving plate is gradually affected by the formation water, expands and deforms, and drives the petal-shaped spring to close. The sample in the sampling tube will not fall off during the lifting process, thereby obtaining a columnar sample with high fidelity. Attached Figure Description

[0011] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and are used to understand the invention. They do not constitute an improper limitation of the invention. In the drawings:

[0012] Figure 1 A schematic diagram of a biomimetic self-closing backstop for a sampling tube in the open state;

[0013] Figure 2 A schematic diagram showing the sampling tube in a closed state using a biomimetic self-closing stopper.

[0014] The markings in the diagram are as follows: 1-Anti-reverse ring; 2-Petal spring; 3-Water-sensitive drive plate; 4-Fixing screw; 5-Rivet; 6-Upper thread; 7-Lower thread; 8-Top hole; 9-Bottom hole. Detailed Implementation

[0015] To more clearly illustrate the present invention, the following description, in conjunction with preferred embodiments and accompanying drawings, further clarifies the invention. Those skilled in the art should understand that the specific description below is illustrative rather than restrictive and should not be construed as limiting the scope of protection of the invention. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains.

[0016] To avoid obscuring the essence of this invention, well-known methods, processes, procedures, and elements are not described in detail.

[0017] like Figure 1 and Figure 2 As shown, a biomimetic self-closing stopper for a sampling tube is based on pine cone scales. It mimics the function of pine cone scales shrinking when dry and opening when absorbing water due to the different distribution of lignin on the inner and outer sides. The opening and closing state of the stopper is controlled by a water-sensitive driving plate 3 that expands when exposed to water. This reduces the disturbance to the sample during the sampling process and prevents the sample from slipping out of the sampling tube during the sample lifting process. The biomimetic self-closing stopper for the sampling tube includes a stop ring 1, a petal-shaped spring 2, a water-sensitive driving plate 3, a fixing screw 4, and a rivet 5. The stop ring 1 is a hollow cylinder with a top hole 8 and a bottom hole 9 on the upper and lower parts, respectively.

[0018] The petal-shaped spring 2 is uniformly fixed in a ring shape to the inner side of the anti-reverse ring 1 by the fixing screw 4. One end of the petal-shaped spring 2 is fixed to the fixing screw 4, and the other end of the petal-shaped spring 2 is a free end. The free ends of the petal-shaped spring 2 can come together to form a closed state. The petal-shaped spring 2 has good resilience. When the anti-reverse device is open, the petal-shaped spring 2 is close to the inner wall of the anti-reverse ring 1 and will not scratch the sample. When the anti-reverse device is closed, the petal-shaped spring 2 bends and closes in the direction of the central axis of the anti-reverse ring 1, which can produce a good blocking effect on the sample.

[0019] One end of the water-sensitive actuating plate 3 is fixedly connected to the petal-shaped spring plate 2 by a rivet 5, and the other end is connected to the inner wall of the anti-reverse ring 1 by a fixing screw 4. The opening and closing of the petal-shaped spring plate 2 is controlled by the water-sensitive actuating plate 3. When dry, the water-sensitive actuating plate 3 is in a contracted state, driving the petal-shaped spring plate 2 to fit tightly against the anti-reverse ring 1; after absorbing water from the sedimentary strata, the water-sensitive actuating plate 3 gradually expands, pushing the petal-shaped spring plate 2 to close.

[0020] The anti-reverse ring 1 has an upper thread 6 and a lower thread 7. It is connected to the sampling tube through the upper thread 6 and to the tube shoe through the lower thread 7, which enables quick disassembly and replacement of the boundary.

[0021] The diameter of the top hole 8 of the anti-reverse ring 1 is 1mm to 2mm smaller than the diameter of the bottom hole 9. The purpose of this is to allow the sample to pass smoothly through the anti-reverse ring 1.

[0022] The opening and closing of the petal-shaped spring 2 is controlled by the water-sensitive drive plate 3. Before sampling, the water-sensitive drive plate 3 is in a dry state and the petal-shaped spring 2 is open. After sampling, the water-sensitive drive plate 3 is in a moist open state and the petal-shaped spring 2 is closed.

[0023] The petal-shaped spring 2 and the water-sensitive driving plate 3 are evenly distributed in a ring on the inner side of the anti-retraction ring 1. Their number can be adjusted according to the characteristics of the formation sample. For loose or easily detached or silt samples, the number of petal-shaped spring 2 and water-sensitive driving plate 3 should be appropriately increased to prevent the sample from falling off.

[0024] The water-sensitive driving sheet 3 described in this invention is made of vulcanized water-swellable rubber.

[0025] The vulcanized water-swellable rubber of the present invention is prepared by emulsion blending. Natural latex is used as the rubber matrix material and polyether polyurethane (PEU) is used as the water-absorbing and swelling component. After the natural latex and polyether polyurethane are stirred and mixed evenly, they are prepared by vacuum dehydration, curing, injection molding and vulcanization.

[0026] The water-sensitive driving sheet 3 described in this invention is a vulcanized water-swellable rubber with a fast water absorption rate and a time required for water absorption, swelling and deformation of less than 30 minutes.

[0027] The specific structural requirements of the water-sensitive driving plate 3 described in this invention are as follows: In the dry state, the water-sensitive driving plate 3 is V-shaped, and under the connection of the rivet 5, it drives the petal-shaped spring 2 to approach the anti-reverse ring 1, and the anti-reverse device is in the open state; in the water-absorbing and swelling state, the water-sensitive driving plate 3 is L-shaped, which drives the petal-shaped spring 2 to deform, and the anti-reverse device is in the closed state.

[0028] The method of using a biomimetic self-closing stopper for sampling tubes proposed in this invention includes the following steps:

[0029] 1. Before obtaining soft sediment with the sampling tube, connect the upper thread 6 to the sampling tube and the lower thread 7 to the tube shoe. The top hole 8 is located at the top and the bottom hole 9 is located at the bottom. Before the sampling operation begins, ensure that the water-sensitive drive plate 3 is in a dry state and the petal-shaped spring plate 2 is in the open state.

[0030] 2. When the sampling operation is carried out, the columnar sample enters the sampling tube through the bottom hole and the backstop. At this time, the water-sensitive drive plate 3 is still in the contracted state, and the petal-shaped spring plate 2 is open. The sediment sample is not subject to resistance or damage during the process of entering the sampling tube.

[0031] 3. After drilling and obtaining sediment samples, the samples are left for a period of time. The water-sensitive drive plate 3 gradually absorbs water and expands, pushing the petal-shaped spring plate 2 to close.

[0032] 4. During the process of lifting the sampling tube, the flap 2 remains closed, and the sample in the sampling tube will not fall out or leak.

[0033] 5. After raising the sampler to the surface, remove the anti-reverse ring 1 and take out the sample;

[0034] 6. In the next sampling operation, replace the old dry anti-reverse ring 1 with a new one, or dry the used anti-reverse ring 1 to restore the water-sensitive drive plate 3 to a dry and contracted state and the petal spring 2 to an open state, so that it can be reused.

[0035] This invention proposes a biomimetic self-closing stop for sampling tubes. When drilling columnar samples from underwater sediments and soft soil, samples are prone to detachment during the lifting process. Conventional conical claw springs cause significant disturbance to the sample's stratigraphy and morphology, making it difficult to obtain low-disturbance in-situ samples, which is detrimental to engineering geological evaluation and geological resource assessment. This invention addresses the disturbance problem in soft, unconsolidated strata by designing a sampling tube stop that opens before core extraction and closes after core extraction, mimicking the characteristic of pine cone scales opening when dry and closing when wet. When the soft sample enters the core extraction tube, the stop is in the open state to prevent scratching and damage to the sample's outer wall. After the sample enters the core extraction tube, the stop is in the closed state to prevent sample detachment during tube lifting. This invention enables low-disturbance, high-fidelity sampling when cored from soft, unconsolidated sediments.

Claims

1. A biomimetic self-closing stopper for sampling tubes, characterized in that, The device includes a backstop ring (1), a petal-shaped spring (2), a water-sensitive drive plate (3), a fixing screw (4), and a rivet (5). The backstop ring (1) is a hollow cylinder with a top hole (8) and a bottom hole (9) on its upper and lower parts, respectively. The backstop ring (1) has an upper thread (6) and a lower thread (7). The backstop ring (1) is connected to the sampling tube through the upper thread (6) and to the tube shoe through the lower thread (7). The petal-shaped spring (2) is uniformly fixed in a ring shape inside the backstop ring (1) by the fixing screw (4). When the backstop is opened, the petal-shaped spring... The spring piece (2) is tightly attached to the inner wall of the anti-reverse ring (1); when the anti-reverse device is closed, the petal-shaped spring piece (2) bends and closes in the direction of the central axis of the anti-reverse ring (1); one end of the water-sensitive driving piece (3) is fixedly connected to the petal-shaped spring piece (2) by a rivet (5), and the other end is connected to the inner wall of the anti-reverse ring (1) by a fixing screw (4); when the water-sensitive driving piece (3) is dry, it is in a contracted state, driving the petal-shaped spring piece (2) to be tightly attached to the anti-reverse ring (1); after the water-sensitive driving piece (3) absorbs water, it gradually expands, pushing the petal-shaped spring piece (2) to bend and close in the direction of the central axis of the anti-reverse ring (1).

2. The biomimetic self-closing stopper for sampling tubes according to claim 1, characterized in that: The diameter of the top hole (8) of the anti-reverse ring (1) is 1 mm to 2 mm smaller than the diameter of the bottom hole (9).

3. The biomimetic self-closing stopper for sampling tubes according to claim 1, characterized in that: The material of the water-sensitive drive sheet (3) is vulcanized water-swellable rubber.

4. The biomimetic self-closing stopper for sampling tubes according to claim 1, characterized in that: The structure of the water-sensitive drive plate (3) is as follows: In the dry state, the water-sensitive drive plate (3) is V-shaped. Under the connection of the rivet (5), it drives the petal-shaped spring (2) to approach the anti-reverse ring (1), so that the anti-reverse device is in the open state; In the water-absorbing and swelling state, the water-sensitive drive plate (3) is L-shaped, which drives the petal-shaped spring (2) to deform, so that the anti-reverse device is in the closed state.

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