A sampling device for deep-sea benthic organisms and injection of in-situ preserving liquid

Abstract

The present application relates to the field of marine equipment, and aims to provide a sampling device for deep-sea benthic organisms and injection of in-situ preservation liquid. The inner cavity of the sampling cylinder is provided with a front piston, a sampling tube and a rear piston; the inner cavity of the sampling tube is provided with a bait bag, a cutter holder and an inner net holder; the inner net holder has a inwardly retracting backflow-preventing opening composed of mesh, and is opposite to the sampling window in the middle of the sampling tube; the inner wall of the sampling cylinder is provided with a limiting structure for blocking the cutter holder, so that the bait bag can be tightly attached to the cutting edge of the cutter holder and be cut by the cutting edge under the pushing force of the transmission mechanism. The sampling tube of the present application adopts a pulling travel mode, and the sealing effect formed by the front and rear pistons and the sampling cylinder facilitates long-time preservation of the sampling sample; the backflow-preventing opening of the inner net holder can prevent organisms from swimming out of the sampling tube, and improve the sampling effectiveness. The vacuum bait bag cooperates with the cutter holder to maximize the freshness of the bait; and the injection of the preservation liquid can improve the sample preservation time.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of marine equipment, and more particularly, to a sampling device for cutting and injecting seabed sediment in situ. BACKGROUND

[0002] During the construction process of seabed mining area, a plume of seabed sediment will be formed and scattered everywhere, and the iron and manganese ions in the plume will affect the marine ecological environment. In order to explore the influence of seabed mining construction on marine organisms, deep seabed organisms need to be sampled in the mining area. Therefore, scientific researchers propose a long-term sampling method, that is, a sampling device is placed on the seabed, and multiple samplers (or sampling tubes) are used for sequential operation, for example, sampling once a month for more than three times. After the entire sampling process is completed, the sampling device is recovered for scientific researchers to study the obtained samples.

[0003] The existing benthic organism sampling device usually sets a baffle at the opening of the sampler cavity, and the bait is directly placed in the inner cavity of the sampler. After the sampling device is lowered to the seabed, the baffles of multiple samplers (or sampling tubes) are opened in sequence to allow benthic organisms to enter. However, such samplers can only be used for short-term sampling, and the built-in bait is easily rotten, which cannot attract benthic organisms and cause sampling failure. In addition, due to the lack of supporting settings for long-term sample preservation, the existing device will cause benthic organisms to rot and lose research value if it is placed for a long time after sampling is completed.

[0004] Therefore, it is necessary to propose a newly designed deep-sea benthic organism sampling device to meet the long-term seabed sampling requirement. SUMMARY

[0005] The technical problem to be solved by the present application is to overcome the shortcomings in the prior art and provide a deep-sea benthic organism sampling and in-situ preservation liquid injection sampling device.

[0006] To solve the technical problem, the solution of the present application is:

[0007] A deep-sea benthic organism sampling and in-situ preservation liquid injection sampling device is provided, comprising an underwater motor, a transmission mechanism, a sampling mechanism and a preservation liquid injection mechanism; wherein,

[0008] The transmission mechanism comprises a transmission housing, a screw sleeve and a lead screw which are coaxially nested in sequence. The screw sleeve is located in the inner cavity of the transmission housing, and the lead screw is fitted and installed at the center of the screw sleeve through external threads. The lead screw is limited by bearings at the end of the transmission housing, and the output end of the underwater motor is connected with the end of the lead screw for driving the lead screw to rotate and moving the screw sleeve along the axial direction;

[0009] The sampling mechanism comprises a hollow cylindrical sampling cylinder body, a front piston, a sampling tube and a rear piston arranged in the inner cavity of the sampling cylinder body; the sampling tube is a cylindrical thin-walled tube structure, and the two ends of the sampling tube are fixedly connected with the front piston and the rear piston respectively to form a combined body, and the two pistons are in sealing fit with the sampling cylinder body; the front piston is fixedly connected with a screw sleeve, and the combined body can move along the axial direction under the driving of the screw sleeve; a preservative liquid injection port, a seawater discharge port and a pressure compensation port are arranged on the sampling cylinder body and are in communication with the inner cavity of the sampling cylinder body; a one-way valve is arranged at the seawater discharge port, and a pressure compensator is arranged at the pressure compensation port;

[0010] A bait bag, a cutter holder and an inner mesh holder are arranged in the inner cavity of the sampling tube in sequence; the bait bag is located at the side of the front piston, the cutter holder is installed on the sampling tube between the bait bag and the inner mesh holder; the inner mesh holder has a inwardly retracting return prevention port formed by a mesh, a sampling window is formed in the middle of the sampling tube, and the return prevention port is located at the sampling window; a limiting structure is arranged on the inner wall of the sampling cylinder body, and the limiting structure can block the cutter holder when the screw sleeve drives the combined body to move, and the bait bag can be tightly attached to the cutting edge of the cutter holder and be cut under the pushing force of the transmission mechanism;

[0011] The preservative liquid injection mechanism comprises a syringe containing preservative liquid, and the outlet end of the syringe is connected to the preservative liquid injection port of the sampling cylinder body through a pipeline and a one-way valve.

[0012] As a preferred scheme of the present application, the end of the screw sleeve is provided with a rotation limiting structure, and the rotation limiting structure cooperates with a limiting groove on the transmission shell to realize limiting, so that the screw sleeve can only move along the axial direction.

[0013] As a preferred scheme of the present application, the sampling cylinder body and the transmission shell are fixedly connected through a bolt.

[0014] As a preferred scheme of the present application, the sampling device further comprises two fixing blocks, each of which is composed of an upper cover and a base; the opposite surfaces of the upper cover and the base are respectively provided with grooves, so that the upper cover and the base can form a through-hole-shaped mounting position after splicing; the transmission shell and the sampling cylinder body are respectively nested and mounted in the fixing blocks, and the bases of the two fixing blocks are fixed on the frame of the sampling platform at the same time.

[0015] As a preferred scheme of the present application, the front piston and the rear piston are both cylindrical metal blocks, and a sealing ring is arranged on the outer edge of each of the front piston and the rear piston in the circumferential direction.

[0016] As a preferred scheme of the present application, the limiting structure is a limiting ring or a limiting protruding part arranged on the inner wall of the sampling cylinder body.

[0017] As a preferred scheme of the present application, the bait bag is a vacuum-packed product in the shape of a round cake, which comprises an outer vacuum plastic packaging film and an inner bait.

[0018] As a preferred scheme of the present application, the inner net frame comprises a support, which is composed of two annular rings at two ends and a plurality of cross bars connecting the annular rings; the mesh is fixed on the cross bars in a way that two meshes are arranged in a group and inwardly and obliquely, and opposite edges of each group of meshes are kept apart to form a backflow-preventing opening; the area between the annular ring and the end of the mesh is closed, so that the inner side of the mesh and the inner wall of the sampling tube jointly enclose a sampling and preserving area.

[0019] As a preferred scheme of the present application, the cutter holder comprises an outer ring, cutter blades and a screen; the cutter blades are at least three and arranged in a cross manner, and the ends thereof are fixed to the inner side of the outer ring; one side of the cutter blade is a blade edge, and the screen is fixed to the back of the blade edge; a gap is kept between the outer edge of the screen and the outer ring; the end of the sampling tube is provided with a plurality of axial slots, and the cutter blades are correspondingly inserted into the slots; the end of the sampling tube is inserted into the gap between the outer edge of the screen and the outer ring, and the outer ring is sleeved on the outer side of the sampling tube.

[0020] As a preferred scheme of the present application, an annular metal ring is welded to the back of the blade edge of the cutter blade, and a gap is kept between the outer edge of the annular metal ring and the outer ring; the screen is circular, and the edge thereof is fixed to the annular metal ring by screws.

[0021] Compared with the prior art, the present application has the following beneficial effects:

[0022] 1. The sampling tube of the present application adopts a pulling travel mode, and can utilize the sealing effect of the two pistons and the sampling cylinder to preserve the sampling sample for a long time; and the problem of poor sealing effect of the conventional sampling device is solved.

[0023] 2. The sampling window is arranged on the sampling tube, and the backflow-preventing opening formed by each group of meshes on the inner net frame is utilized to facilitate the entry of the biological sample, and to avoid the escape of the biological body from the sampling tube by using a crab cage escape-preventing mechanism, so that the sampling effectiveness is improved.

[0024] 3. The bait package of the vacuum packaging product is adopted in the present application, and the bait is sealed in the bait package by using the external plastic film and the vacuum sealing process. Based on the long-time sampling setting, the bait package is only cut by the cutter holder when sampling in the later period, so that the bait can be released. This design can ensure the freshness of the bait to the greatest extent, and solves the problem that the traditional bait starts to deteriorate as soon as it is put into water and is difficult to store for a long time.

[0025] 4. The preserving liquid injection mechanism is utilized in the present application, so that the preserving liquid (alcohol or formalin) can be injected into the inner cavity of the sampling tube after sampling, so that the storage time of the sample after sampling is improved. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 It is the overall structural diagram of the sampling device of the present application;

[0027] Figure 2 is an internal sectional view of the transmission mechanism;

[0028] Figure 3 is an internal sectional view of the sampling mechanism;

[0029] Figure 4 is a schematic view of the cooperation between the sampling cylinder and the cutter holder and the limiting ring;

[0030] Figure 5 is a schematic view of the structure of the cutter holder;

[0031] Figure 6 is a schematic view of the structure of the inner net holder;

[0032] Figure 7 is a schematic view of the sampling tube after being extended.

[0033] The reference signs in the drawings are as follows: 1 sampling mechanism; 1-1 front piston; 1-2 rear piston; 1-3 sampling cylinder; 1-4 bait bag; 1-5 cutter holder; 1-5-1 outer ring; 1-5-2 cutter blade; 1-5-3 screen; 1-6 inner net holder; 1-6-1 support; 1-6-2 mesh; 1-7 limiting ring; 1-8 sampling tube; 1-9 preservative liquid injection port; 1-10 seawater discharge port; 2 transmission mechanism; 2-1 transmission housing; 2-2 screw sleeve; 2-3 screw rod; 3 underwater motor; 4 fixed block; 5 preservative liquid injection mechanism. DETAILED DESCRIPTION

[0034] The technical solutions of the present application will be described in detail below with reference to the drawings. It should be noted that the description of these embodiments is used to help understand the present application, but does not constitute a limitation on the present application.

[0035] In the present application, the serial numbers of components, such as "first", "second", etc., are used only to distinguish the described objects, and do not have any sequence or technical meaning. In the present application, "connection" and "coupling" include direct and indirect connection (coupling) unless otherwise specified. In the description of the present application, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate the orientation or positional relationship shown in the drawings, and are only used to facilitate the description of the present application and simplify the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0036] In the present application, unless otherwise explicitly specified and limited, a first feature is "on" or "under" a second feature can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature is "above", "over" and "on" the second feature can be that the first feature is directly above or obliquely above the second feature, or only indicates that the first feature is higher in horizontal height than the second feature. The first feature is "below", "under" and "under" the second feature can be that the first feature is directly below or obliquely below the second feature, or only indicates that the first feature is lower in horizontal height than the second feature.

[0037] It should be particularly pointed out that only the necessary structure and components of the sampling device are described in detail in the present application. Based on the knowledge of those skilled in the art, such devices need to be equipped with communication devices, control devices, hooks (or handles) and other necessary accessories to perform the sampling task. However, the applicant believes that those skilled in the art can select or configure related accessories or auxiliary structures according to their skills and in combination with existing known technologies to correctly perform the sampling task. Since these auxiliary technical contents are not the core technology of the present application and do not have a substantial impact on the technical implementation of the present application, the present application will not be described in detail.

[0038] As shown in the deep-sea benthic organism sampling and in-situ preservation liquid injection sampling device shown in Figure 1 , 7 , comprising a sampling mechanism 1, a transmission mechanism 2, an underwater motor 3, a fixing block 4 and a preservation liquid injection mechanism 5; wherein:

[0039] The transmission mechanism 2 comprises a transmission shell 2-1, a screw sleeve 2-2 and a lead screw 2-3 which are coaxially nested in sequence; the screw sleeve 2-2 is located in the inner cavity of the transmission shell 2-1, the lead screw 2-3 is adaptively installed in the center of the screw sleeve 2-2 through external threads, and the lead screw 2-3 is limited by bearings at the ends of the transmission shell 2-1. The end of the screw sleeve 2-2 is provided with a rotation limiting structure which cooperates with the limiting groove on the transmission shell 2-1 to limit the movement of the screw sleeve 2-2 in the axial direction. The underwater motor 3 is a waterproof motor, the output end of which is connected with the end of the lead screw 2-3, for driving the lead screw 2-3 to rotate and in turn driving the screw sleeve 2-2 to move in the axial direction.

[0040] The sampling mechanism 1 comprises a hollow cylindrical sampling cylinder 1-3, in the inner cavity of which a front piston 1-1, a sampling tube 1-8 and a rear piston 1-2 are arranged; the sampling cylinder 1-3 is fixedly connected with the transmission shell 2-1 by bolts.

[0041] The fixing block 4 has two, each of which is composed of an upper cover and a base; the opposite surfaces of the upper cover and the base are respectively provided with grooves, which can form a through-hole-shaped mounting position after splicing. The transmission shell 2-1 and the sampling cylinder 1-3 are respectively nested in one fixing block, and the bases of the two fixing blocks 4 are fixed on the frame of the sampling platform at the same time.

[0042] The sampling tube 1-8 is a cylindrical thin-walled tube structure, and its two ends are fixedly connected with the front piston 1-1 and the rear piston 1-2 respectively to form a combination. The front piston 1-1 and the rear piston 1-2 are both cylindrical metal blocks, and a sealing ring is arranged on the outer edge of each in the circumferential direction. The two pistons are in sealing fit with the sampling cylinder body 1-3; the front piston 1-1 is fixedly connected with the screw sleeve 2-2, and can move the combination in the axial direction under the driving of the latter. The sampling cylinder body 1-3 is provided with a preservative injection port 1-9, a seawater discharge port 1-10 and a pressure compensation port (not shown in the figure), which are all in communication with the inner cavity of the sampling cylinder body 1-3; a one-way valve is arranged at the seawater discharge port 1-10, and a pressure compensator (not shown in the figure) is arranged at the pressure compensation port.

[0043] In the inner cavity of the sampling tube 1-8, a bait package 1-4, a cutter holder 1-5 and an inner net holder 1-6 are arranged in sequence.

[0044] The bait package 1-4 is a vacuum-packed product in the shape of a round cake, which includes an outer vacuum plastic packaging film and an inner bait. The bait package 1-4 is located on the side of the front piston 1-1, and the cutter holder 1-5 is installed on the sampling tube 1-8 between the bait package 1-4 and the inner net holder 1-6. A limiting structure is arranged on the inner wall of the sampling cylinder body 1-3, which can be a limiting ring 1-7 (or a limiting protrusion) arranged on the inner wall of the sampling cylinder body. When the screw sleeve 2-2 drives the combination to move, the limiting structure can block the cutter holder 1-5, and the bait package 1-4 can be tightly attached to the cutting edge of the cutter holder 1-5 and be cut under the pushing force of the transmission mechanism 2.

[0045] The inner net holder 1-6 includes a support 1-6-1, which is composed of two circular rings at both ends and a plurality of horizontal rods connecting the circular rings. The mesh 1-6-2 is fixed on the horizontal rods in a way that two groups of mesh 1-6-2 are arranged inwardly and obliquely, and the opposite edges of each group of mesh 1-6-2 are kept apart to form a inwardly converging return stop. A sampling window is opened in the middle of the sampling tube 1-8, and the return stop is located at the sampling window. The area between the circular ring and the end of the mesh is closed, so that the inner side of the mesh 1-6-2 and the inner wall of the sampling tube 1-8 together form a sampling and preservation area.

[0046] The cutter holder 1-5 comprises an outer ring 1-5-1, cutter blades 1-5-2 and a screen 1-5-3. The cutter blades 1-5-2 are at least three and arranged in cross, and the ends thereof are fixed to the inner side of the outer ring 1-5-1. One side of the cutter blades 1-5-2 is a cutting edge, and the screen 1-5-3 is fixed to the back of the cutting edge, and a gap is reserved between the outer edge of the screen 1-5-3 and the screen 1-5-1. The end of the sampling tube 1-8 is provided with a plurality of axial notches, and the cutter blades 1-5-2 are inserted into the notches one by one. The end of the sampling tube 1-8 is inserted into the gap between the outer edge of the screen 1-5-3 and the outer ring 1-5-1, and the outer ring 1-5-1 is sleeved on the outer side of the sampling tube 1-8. As an optional solution, a ring-shaped metal ring is welded on the back of the cutting edge of the cutter blades 1-5-2, and a gap is reserved between the outer edge of the ring-shaped metal ring and the outer ring 1-5-1. The screen 1-5-3 is circular, and the edge thereof is fixed on the ring-shaped metal ring by screws.

[0047] The preservative injection mechanism 5 comprises a syringe containing preservative, and the outlet end thereof is connected to the preservative injection port on the sampling cylinder 1-3 through a pipeline and a one-way valve.

[0048] More specific examples are as follows:

[0049] As shown in Figure 1 , the sampling device for deep-sea benthic organisms and in-situ preservative injection comprises a sampling mechanism 1, a transmission mechanism 2, an underwater motor 3, a fixing block 4 and a preservative injection mechanism 5. Among them:

[0050] As shown in Figure 2 , the transmission mechanism 2 comprises a transmission housing 2-1, a screw sleeve 2-2 and a screw rod 2-3. The screw rod 2-3 is limited by bearings and the transmission housing 2-1, and is used for converting the rotary motion of the underwater motor 3 into linear motion. The end of the screw sleeve 2-2 has rotary limiting structure, which cooperates with the limiting hole on the inner wall of the transmission housing 2-1 to limit the movement of the screw sleeve 2-2, so that the screw sleeve 2-2 can only move forward and backward. When the underwater motor 3 works, the screw rod 2-3 rotates to drive the screw sleeve 2-2 to move forward and backward, thereby driving the sampling tube 1-8 to move forward and backward.

[0051] As shown in Figures 3-7 , the sampling mechanism 1 comprises a front piston 1-1, a rear piston 1-2, a sampling cylinder 1-3, a bait bag 4, a cutter holder 1-5, an inner net holder 1-6, a limiting ring 1-7 and a sampling tube 1-8, which are used for sampling benthic organisms. The sampling cylinder 1-3 is a columnar housing, and the sampling cylinder 1-3 is provided with a preservative injection port 1-9, a seawater discharge port 1-10 and a pressure compensator port which are in communication with the inner cavity, and are respectively connected to an inward one-way valve, an outward one-way valve and a pressure compensator. The inward one-way valve is connected to a syringe through a pipeline, and is used for injecting alcohol (or formalin) after sampling; the outward one-way valve is used for discharging seawater when injecting alcohol (or formalin), and the preservation of the sampling sample is realized by liquid displacement.

[0052] As shown in Figure 3 , 4 , the sampling tube 1-8 is a cylindrical thin-walled tube, with a square sampling window in the middle for benthic organisms to enter, and four notches at the front end for fitting the cutter blade 1-5-2 of the cutter holder 1-5. The front piston 1-1 and the rear piston 1-2 are cylindrical metal blocks, and the two ends of the sampling tube 1-8 are fixedly connected with the front piston 1-1 and the rear piston 1-2 through bolts. The outer sides of the front piston 1-1 and the rear piston 1-2 are provided with sealing rings, which can form a sealed fit with the sampling cylinder body 1-3. The front piston 1-1 is connected with the screw sleeve 2-2 in the transmission mechanism 2. The bait bag 4 is a vacuum-packed bait for benthic organisms to eat, which is placed behind the front piston 1-1. The cutter holder 1-5 is placed behind the bait bag 4, which is used to cut open the bait bag 4 when the sampling tube 1-8 is pushed out of the limited position. The net plates on the inner net holder 1-6 form a backstop, which is based on the backstop mechanism similar to a crab trap to allow benthic organisms to enter and not to go out. The limiting ring 1-7 is a circular ring with an inner diameter larger than the outer diameter of the sampling tube 1-8, which is fixed on the inner wall surface of the sampling cylinder body 1-3, and is used as a limited position when the sampling tube 1-8 is pushed out.

[0053] As shown in Figure 5 , the cutter holder 1-5 includes an outer ring 1-5-1, a cutter blade 1-5-2, and a screen 1-5-3. The outer ring 1-5-1 is located between the sampling tube 1-8 and the sampling cylinder body 1-3. The cutter blade 1-5-2 is two metal blades distributed in cross, and the end is welded to the inner wall of the outer ring 1-5-1. The cutter blade 1-5-2 passes through the four notches at the front end of the sampling tube 1-8, so that the outer ring 1-5-1 is fitted on the periphery of the sampling tube 1-8. The screen 1-5-3 is a circular net-shaped plate with an outer diameter smaller than the inner diameter of the sampling tube 1-8, which is located inside the sampling tube 1-8 and fixed on the back of the cutter blade 1-5-2. When the front piston 1-1 pushes the bait bag 4 and the cutter holder 1-5 is displaced to the limiting ring 1-7, the bait bag 4 is further squeezed and damaged by the cutter blade 1-5-2, and the bait inside enters the sampling tube 1-8 from the screen 1-5-3, which is used to attract benthic organisms.

[0054] As shown in Figure 6 , the inner net holder 1-6 includes a support 1-6-1 and a mesh 1-6-2. The support 1-6-1 is composed of two circular rings and four slender cylindrical rods welded in the middle. The mesh 1-6-2 is fixed on the support 1-6-1, and the meshes 1-6-2 in the same group are kept apart and form a backstop similar to a crab trap. The area between the circular ring and the end of the mesh 1-6-2 is closed, so that the inner side of the mesh and the inner wall of the sampling tube together form a sampling and preservation area.

[0055] The example operation sequence is as follows:

[0056] (1) Preparation:

[0057] On the mother ship, the sampling tube 1-8 is retracted into the sampling cylinder, and the bait bag 4 is located between the cutter blade 1-5-2 and the front piston 1-1.

[0058] (2) Deployment:

[0059] The sampling device is deployed to the target sea area by a lander or ROV. Under remote control or local automatic control, the action time of the underwater motor 3 is set according to the sampling time node.

[0060] (3) Sampling:

[0061] At the set time point, the underwater motor 3 drives the sampling tube 1-8 to extend out of the sampling cylinder body 1-3 until the outer ring 1-5-1 collides with the limiting ring 1-7, and the cutter blade 1-5-2 cuts open the vacuum bait bag 4. At this time, the bait falls from the screen 1-5-3, and the benthic organisms are induced to enter the sampling tube 1-8 from the check valve and are restricted from swimming outwards.

[0062] (4) Preservation:

[0063] The underwater motor 3 drives the sampling tube 1-8 to retract into the sampling cylinder body 1-3, and the two pistons together with the sampling cylinder body 1-3 form a seal for the sampling tube 1-8. Sampling is completed, and preservative liquid is injected into the sampling cylinder body 1-3 to replace seawater.

[0064] (5) Recovery:

[0065] The sampling device is retrieved using a cable or ROV, and the pressure compensator is used to maintain the pressure inside the sampling cylinder body 1-3 unchanged during the ascent.

Claims

1. A deep-sea benthic organism sampling and in-situ preservation liquid injection sampling device, characterized by, The underwater motor, the transmission mechanism, the sampling mechanism and the preservative liquid injection mechanism are included. The transmission mechanism includes a transmission shell, a screw sleeve and a screw rod which are coaxially installed in sequence. The sampling mechanism includes a hollow cylindrical sampling cylinder, a front piston, a sampling pipe and a rear piston which are arranged in the inner cavity of the sampling cylinder. The sampling pipe is a cylindrical thin-walled pipe structure, and its two ends are fixedly connected with the front piston and the rear piston respectively to form a combined body. The two pistons are in sealing fit with the sampling cylinder. The front piston is fixedly connected with the screw sleeve and can move the combined body in the axial direction under the driving of the screw sleeve.

2. The sampling device of claim 1, wherein, A preservative liquid injection port, a seawater discharge port and a pressure compensator port are arranged on the sampling cylinder and are in communication with the inner cavity of the sampling cylinder.

3. The sampling device of claim 1, wherein, A one-way valve is arranged at the seawater discharge port, and a pressure compensator is arranged at the pressure compensator port. A bait bag, a cutter holder and an inner mesh holder are arranged in the inner cavity of the sampling pipe in sequence. The bait bag is located on the side of the front piston, and the cutter holder is installed on the sampling pipe between the bait bag and the inner mesh holder. The inner mesh holder has a mesh composed of a reentrant port which is inwardly retracted. A sampling window is opened in the middle of the sampling pipe, and the reentrant port is located at the sampling window. A limiting structure is arranged on the inner wall of the sampling cylinder. When the screw sleeve drives the combined body to move, the limiting structure can block the cutter holder. The bait bag can be tightly attached to the cutting edge of the cutter holder and be cut under the thrust of the transmission mechanism. The inner mesh holder includes a support which is composed of two annular rings and a plurality of crossbars connected with the annular rings. The mesh is fixed on the crossbars in a way that two meshes are arranged in a group and are inwardly and obliquely arranged. The opposite edges of each group of meshes are kept apart to form a reentrant port. The area between the annular ring and the end of the mesh is closed to form a sampling and preservation area together with the inner wall of the sampling pipe. The cutter holder includes an outer ring, cutter blades and a screen. The cutter blades are at least three and are arranged in a cross manner. The end of the sampling pipe is provided with a plurality of axial notches, and the cutter blades are inserted into the notches one by one. The end of the sampling pipe is inserted into the gap between the outer edge of the screen and the outer ring, and the outer ring is sleeved on the outside of the sampling pipe. The preservative liquid injection mechanism includes an injector with preservative liquid which is connected to the preservative liquid injection port of the sampling cylinder through a pipeline and a one-way valve. The end of the screw sleeve is provided with a rotation limiting structure which is matched with a limiting groove on the transmission shell to limit the axial displacement of the screw sleeve. The sampling cylinder and the transmission shell are fixedly connected by bolts. The sampling cylinder and the transmission shell are fixedly connected by bolts.

4. The sampling device of claim 1, wherein, The sampling device further comprises two fixing blocks, each of which is composed of an upper cover and a base; opposite surfaces of the upper cover and the base are respectively provided with grooves, which can form a through-hole-shaped mounting position after splicing; the transmission housing and the sampling cylinder body are respectively nested in the fixing blocks, and the bases of the two fixing blocks are fixed on the frame of the sampling platform at the same time.

5. The sampling device of claim 1, wherein, The front and rear pistons are cylindrical metal blocks, and a sealing ring is arranged on the outer edge of each piston in the circumferential direction.

6. The sampling device of claim 1, wherein, The limiting structure is a limiting ring or a limiting protruding part arranged on the inner wall of the sampling cylinder body.

7. The sampling device of claim 1, wherein, The bait package is a vacuum-packed product in the shape of a round cake, which comprises an external vacuum plastic packaging film and internal bait.

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