A float fixed depth sampling device for polluted water bodies

Abstract

The present invention relates to the technical field of water sampling, and specifically to a float fixed-depth sampling device for polluted water bodies, comprising a suspension rope, a sampling bucket, a float and a pull rope; a sliding frame is provided on a sliding sleeve on the suspension rope, and the float is horizontally slidably mounted on the slide rack and connected to the slide rack via an elastic member; a winding unit is provided on the slide rack; a piston plate is slidably mounted up and down in the sampling bucket, the piston plate is connected to the sampling bucket via an elastic rope, and the piston plate is connected to the suspension rope via a piston column. The movement of the piston column is limited by providing a stop assembly, and the release of the pull rope is adjusted according to the movement of the float under the action of the water flow. The stop assembly is unlocked by using the pull rope connected to the float. When the sampling bucket reaches the sampling depth, the pull rope is just tightened to release the restriction of the stop assembly on the piston column, ensuring that the sampling bucket samples at the sampling depth, eliminating the influence of the movement of the float under the action of the water flow on the sampling depth of the sampling bucket, and making sampling more accurate.

Description

Technical Field

[0001] The invention relates to the technical field of water sampling, and in particular to a float fixed-depth sampling device for polluted water bodies. Background Art

[0002] Depth sampling is a commonly used sampling method for water quality monitoring. Its purpose is to obtain water samples at specific depths for analysis and research. It is widely used in water quality monitoring and environmental research. When analyzing polluted water, sampling is often performed at multiple depths to characterize water quality at different depths.

[0003] Existing fixed-depth sampling devices typically utilize the buoyancy of a float to maintain the device at a specific water depth. For example, patent publication number CN219694621U discloses a geological environment detection sampler. When the sampling tube sinks to a specified depth, the upward pull of the float on the pull rope and the downward pull of the sampling tube on the pull rope disengage the sliding rod stuck on the sampling tube and release the restriction on the blocking rod, triggering the depth-setting device to automatically sample. However, since the float is easily affected by the water flow when floating on the water surface, if it deviates, it will trigger the depth-setting device to automatically sample prematurely through the pull rope, causing errors in the sampling depth of the sampling tube and affecting sampling accuracy. Summary of the Invention

[0004] The invention provides a float fixed-depth sampling device for polluted water bodies, which solves the problem that the sampling accuracy is affected by float deviation during sampling in the existing sampler.

[0005] The float fixed depth sampling device for polluted water bodies of the present invention adopts the following technical solutions:

[0006] The buoy is installed on the sliding frame to slide in the water, and the buoy is installed on the sliding frame to slide in a horizontal direction and connected to the sliding frame by an elastic member; a winding unit is provided on the sliding frame; the sampling barrel is arranged vertically, with an open top and a sealed bottom, and a one-way valve allowing water to flow in is provided at the bottom of the sampling barrel; a piston plate is installed in the sampling barrel to slide up and down, and the piston plate is connected to the sampling barrel by an elastic rope, and the piston plate is connected to the buoy through the piston column; a stop assembly for limiting the up and down movement of the piston column is provided between the piston column and the sampling barrel; one end of the pull rope is connected to the winding unit, and the other end passes through the float and is connected to the stop assembly; the winding unit releases the pull rope when the float moves relative to the lifting rope, and makes the length of the pull rope between the float and the stop assembly positively correlated with the moving distance of the float; the pull rope is tightened when the sampling barrel reaches the sampling depth and releases the restriction of the stop assembly on the piston column.

[0007] Optionally, the stopping assembly includes an articulated rod and a wedge block, the articulated rod is perpendicular to the axial direction of the sampling barrel, and the middle part is hinged to the sampling barrel around a horizontal axis, one end of the articulated rod is connected to the pull rope, and the other end is connected to the wedge block for sliding along the axial direction of the sampling barrel; the wedge block is installed on the sampling barrel for radial sliding along the sampling barrel, and a wedge-shaped groove for cooperating with the wedge block is provided on the outer peripheral wall of the piston column; a torsion spring is connected between the articulated rod and the sampling barrel, and the torsion spring prompts the wedge block to cooperate with the wedge groove through the articulated rod, thereby limiting the up and down movement of the piston column; when the pull rope is tightened, it drives the articulated rod to rotate, and the articulated rod pulls the wedge block to move and disengage from the wedge groove.

[0008] Optionally, the winding unit includes a winding wheel, an adjusting wheel, a transmission wheel and a transmission rod; the winding wheel and the adjusting wheel are both rotatably installed on the sliding frame, one end of the pull rope is connected to and wrapped around the winding wheel, then passes through the adjusting wheel and passes through the float to be connected to the hinged rod; the transmission wheel is coaxial with the adjusting wheel and rotates synchronously; the transmission rod is connected to the float and extends along the sliding direction of the float on the sliding frame, and cooperates with the transmission wheel; the movement of the float drives the adjusting wheel to rotate through the transmission rod and the transmission wheel, thereby increasing the release amount of the pull rope.

[0009] Optionally, the regulating wheel is a multi-stage variable speed wheel, which can change its rotation speed and the ratio of its release to the rope pulling amount.

[0010] Optionally, the adjusting wheel includes a central shaft and a sleeve, the central shaft is perpendicular to the transmission rod and parallel to the winding wheel, the central shaft is rotatably mounted on the sliding frame, and the transmission wheel is coaxially and fixedly mounted on the central shaft; the sleeve is sleeved outside the central shaft and rotates synchronously with the central shaft, and a plurality of wire grooves with successively increasing diameters are opened outside the sleeve. The sleeve is replaced with different wire grooves to wrap the pull rope, so as to release pull ropes of different lengths under the same displacement of the float.

[0011] Optionally, the adjusting wheel also includes a ball, which is connected to the countersunk hole opened in the inner ring of the sleeve through a spring; a plurality of transmission grooves are opened on the central shaft along its axial direction, and the ball cooperates with different transmission grooves to enable the sleeve to rotate synchronously with the central shaft; the sleeve moves along the central axis so that the ball is stuck in different transmission grooves, so that the wire groove used for winding the pull rope corresponds to the middle part of the winding wheel.

[0012] Optionally, one end of the elastic rope is connected to the piston plate, and the other end of the elastic rope passes upward over the upper end of the sampling barrel in the sampling barrel and then extends downward to be connected to the outer wall of the sampling barrel.

[0013] Optionally, a stop arm is fixedly provided on the upper end of the sampling barrel, which provides an installation position for the hinged rod and the wedge block, guides the up and down movement of the piston column, and prevents the piston plate from moving upward and separating from the sampling barrel.

[0014] Optionally, a discharge port is provided at the bottom of the sampling barrel, and a sealing plug is detachably installed at the discharge port.

[0015] Optionally, a hook is connected to the float, and the pull rope is wound around the adjusting wheel and then passes through the hook to be connected to the hinged rod.

[0016] The beneficial effects of the present invention are as follows: the float fixed-depth sampling device for polluted water bodies of the present invention limits the movement of the piston column by setting a stop assembly, and adjusts the release of the pull rope according to the movement of the float under the action of water flow, and uses the pull rope connected to the float to unlock the stop assembly. When the sampling bucket reaches the sampling depth, the pull rope is just tightened to release the restriction of the stop assembly on the piston column, ensuring that the sampling bucket samples at the sampling depth, eliminating the influence of the movement of the float under the action of water flow on the sampling depth of the sampling bucket, and making sampling more accurate.

[0017] Furthermore, the regulating wheel is a multi-stage variable speed wheel, which can change the ratio of its rotation speed to the amount of rope release, so as to adjust the amount of rope release according to different sampling depths of the sampling barrel and adapt to different sampling depths of the sampling barrel. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 This is a schematic diagram of the overall structure of an embodiment of a float fixed-depth sampling device for polluted water bodies of the present invention;

[0020] Figure 2 for Figure 1 A magnified schematic diagram of point A in the middle;

[0021] Figure 3 This is a front view of the overall structure of an embodiment of a float fixed depth sampling device for polluted water bodies of the present invention;

[0022] Figure 4 for Figure 3 Schematic diagram of the cross section along the middle BB direction;

[0023] Figure 5 It is a cross-sectional schematic diagram of an embodiment of a float fixed-depth sampling device for polluted water bodies of the present invention;

[0024] Figure 6 for Figure 5 Enlarged schematic diagram of point C in the middle.

[0025] In the figure: 100, lifting rope; 110, sliding frame; 120, elastic member; 130, winding unit; 131, winding wheel; 132, adjusting wheel; 1321, central shaft; 1322, bushing; 1323, marble; 1324, transmission groove; 1325, wire groove; 133, transmission wheel; 134, transmission rod; 200, sampling barrel; 210, piston plate; 220, elastic rope; 230, piston column; 240, stop assembly; 241, hinged rod; 242, wedge; 250, stop arm; 260, discharge outlet; 270, one-way valve; 300, float; 310, hook ring; 400, pull rope. DETAILED DESCRIPTION

[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0027] An embodiment of a float fixed depth sampling device for polluted water bodies of the present invention is as follows Figures 1 to 6 As shown, it includes a hanging rope 100 , a sampling bucket 200 , a floating ball 300 and a pulling rope 400 .

[0028] The sling rope 100 is slidably sleeved with a sliding frame 110 , and the float 300 is horizontally slidably mounted on the sliding frame 110 and connected to the sliding frame 110 via an elastic member 120 , wherein the elastic member 120 is a tension spring. A winding unit 130 is provided on the sliding frame 110 .

[0029] The sampling barrel 200 is vertically mounted, with an open top and a sealed bottom. A one-way valve 270 is installed at the bottom of the barrel to allow water to enter. A piston plate 210 is mounted within the barrel 200, sliding upward. This plate is connected to the barrel 200 via an elastic cord 220, which forces the plate 210 to move upward. The piston plate 210 is connected to the suspension rope 100 via a piston rod 230. A stop assembly 240 is located between the piston rod 230 and the barrel 200 to limit its upward movement.

[0030] One end of the pull rope 400 is connected to the winding unit 130, and the other end passes through the float 300 and is connected to the stop assembly 240; the winding unit 130 releases the pull rope 400 when the float 300 moves relative to the suspension rope 100, and makes the length of the pull rope 400 between the float 300 and the stop assembly 240 positively correlated with the moving distance of the float 300; the pull rope 400 is tightened when the sampling barrel 200 reaches the sampling depth and releases the restriction of the stop assembly 240 on the piston column 230.

[0031] Before the sampling barrel 200 is launched into the water, the piston plate 210 must be moved to the bottom of the sampling barrel 200, and the stop assembly 240 must be used to restrict the upward and downward movement of the piston rod 230. Simultaneously, the winding unit 130 releases a drawstring 400 corresponding to the sampling depth of the sampling barrel 200. The sampling barrel 200 enters the water with its bottom facing downward and moves downward under its own gravity. Simultaneously, the float 300 floats on the water surface and, under the influence of the current, is positioned on the backwater side of the suspension rope 100. Under the influence of the current, the float 300 moves along the sliding frame 110, causing the winding unit 130 to release the drawstring 400, increasing the length of the drawstring 400 between the float 300 and the stop assembly 240, thereby compensating for the error in the actual effective length of the drawstring 400 caused by the movement of the float 300 with the current. By reasonably configuring the ratio of the amount of release of the pull rope 400 by the winding unit 130 and the movement of the float 300, the pull rope 400 can be just tightened when the sampling barrel 200 reaches the sampling depth, thereby triggering the stop assembly 240 to release the restriction of the stop assembly 240 on the piston column 230. The piston plate 210 moves upward under the tension of the elastic rope 220, and the water sample is sucked into the sampling barrel 200 through the one-way valve 270 at the bottom of the sampling barrel 200.

[0032] By setting a stop assembly 240 to limit the movement of the piston column 230, and adjusting the release of the pull rope 400 according to the movement of the float 300 under the action of water flow, the stop assembly 240 is unlocked by using the pull rope 400 connected to the float 300. When the sampling barrel 200 reaches the sampling depth, the pull rope 400 is just tightened to release the restriction of the stop assembly 240 on the piston column 230, ensuring that the sampling barrel 200 samples at the sampling depth, eliminating the influence of the movement of the float 300 under the action of water flow on the sampling depth of the sampling barrel 200, and making sampling more accurate.

[0033] In this embodiment, the stop assembly 240 includes a hinged rod 241 and a wedge 242. The hinged rod 241 is perpendicular to the axis of the sampling barrel 200 and hinged to the sampling barrel 200 at its center about a horizontal axis. One end of the hinged rod 241 is connected to the pull rope 400, and the other end is connected to the wedge 242 for sliding and rotational movement along the axis of the sampling barrel 200. The wedge 242 is mounted in the sampling barrel 200 for radial sliding movement. The outer wall of the piston column 230 is provided with a wedge-shaped groove for engaging with the wedge 242. A torsion spring (not shown) is connected between the hinged rod 241 and the sampling barrel 200. The torsion spring, via the hinged rod 241, forces the wedge 242 to engage with the wedge groove, thereby limiting the vertical movement of the piston column 230. When the pull rope 400 is tightened, the hinged rod 241 rotates, and the hinged rod 241 pulls the wedge 242 out of the wedge groove. Specifically, a sliding groove parallel to the axial direction of the sampling barrel 200 is opened on the wedge block 242, and the other end of the hinged rod 241 slides and rotates with the sliding groove. The hinged rod 241 is in a horizontal state under the action of the torsion spring. At the same time, the wedge block 242 cooperates with the wedge-shaped groove. When the hinged rod 241 rotates under the drive of the pull rope 400, it drives the wedge block 242 to move radially along the sampling barrel 200, so that the wedge block 242 is disengaged from the wedge-shaped groove.

[0034] In this embodiment, the winding unit 130 includes a reel 131, an adjusting wheel 132, a transmission wheel 133, and a transmission rod 134. Both the reel 131 and the adjusting wheel 132 are rotatably mounted on the sliding frame 110. One end of the pull rope 400 is connected to and wound around the reel 131. The rope then passes over the adjusting wheel 132, through the float 300, and is connected to the hinged rod 241. The transmission wheel 133 and the adjusting wheel 132 are coaxial and rotate synchronously. The transmission rod 134 is connected to the float 300 and extends along the sliding direction of the float 300 on the sliding frame 110, cooperating with the transmission wheel 133. The movement of the float 300 through the transmission rod 134 and the transmission wheel 133 drives the adjusting wheel 132 to rotate. The rotation of the adjusting wheel 132 drives the reel 131 through the rope 400, causing the rope 400 to detach from the reel 131 and increase the amount of rope 400 released. The transmission wheel 133 is a gear and the transmission rod 134 is a rack, or the transmission wheel 133 is a friction wheel and the transmission rod 134 is a friction rod. To ensure that the pull rope 400 can only be released when the adjustment wheel 132 rotates and to prevent the pull rope 400 from slipping on the adjustment wheel 132, the mating position of the pull rope 400 and the adjustment wheel 132 can be configured to engage with teeth.

[0035] In this embodiment, the regulating wheel 132 is a multi-speed variable wheel that can change its rotational speed and the ratio of its release to the amount of the pull rope 400 to adjust the release of the pull rope 400 according to different sampling depths of the sampling barrel 200.

[0036] In this embodiment, the adjusting wheel 132 includes a central shaft 1321 and a sleeve 1322. The central shaft 1321 is perpendicular to the transmission rod 134 and parallel to the winding wheel 131. The central shaft 1321 is rotatably mounted on the sliding frame 110, and the transmission wheel 133 is coaxial and fixedly mounted on the central shaft 1321. The sleeve 1322 is sleeved outside the central shaft 1321 and rotates synchronously with the central shaft 1321. A plurality of wire grooves 1325 with increasing diameters are provided on the outside of the sleeve 1322. The sleeve 1322 is replaced with different wire grooves 1325 to wrap the pull rope 400 so as to release pull ropes 400 of different lengths under the same displacement of the float 300. Specifically, in the initial state, the vertical distance between the connection position of the pull rope 400 and the float 300 and the axis of the sampling barrel 200 is set to a, and the sampling depth of the sampling barrel 200 is set to h. Then the effective length of the pull rope 400 between the float 300 and the sampling barrel 200 is L=√(a 2 +h 2 When the float 300 floats on the water surface, the distance it moves under the action of the water flow is △a, so the effective length of the pull rope 400 that needs to be increased is △L=√(a 2 +h 2 +2*a*△a+△a 2 ) - L. In areas with slow water flow, the distance △a moved by the float 300 under the influence of the current is small. Using differential approximation, we can derive the relationship between the increments: the required effective length of the pull rope 400 is △L ≈ (a / L) * △a. The proportional relationship between the required effective length △L of the pull rope 400 and the distance △a moved by the float 300 varies with the sampling depth h. Therefore, after determining the sampling depth h, the adaptable wire groove 1325 can be replaced to match the pull rope 400, ensuring that the increased release of the pull rope 400 and the distance moved by the float 300 meet the aforementioned proportional relationship.

[0037] In this embodiment, the adjustment wheel 132 further includes a pin 1323, which is connected to a countersunk hole defined within the inner ring of the sleeve 1322 via a spring. A plurality of transmission slots 1324 are defined along the axial direction of the central shaft 1321. The pins 1323 engage with different transmission slots 1324 to cause the sleeve 1322 to rotate synchronously with the central shaft 1321. As the sleeve 1322 moves along the central shaft 1321, the pins 1323 engage with different transmission slots 1324, causing the wire groove 1325 for winding the draw cord 400 to align with the center portion of the reel 131, facilitating rotation of the reel 131 to release the draw cord 400.

[0038] In this embodiment, one end of the elastic cord 220 is connected to the piston plate 210, and the other end extends upward within the sampling barrel 200, passes over the upper end of the sampling barrel 200, and then extends downward to connect to the outer wall of the sampling barrel 200. Specifically, there are multiple elastic cords 220, evenly distributed around the circumference of the sampling barrel 200. Multiple connecting rings are provided circumferentially around the lower end of the outer wall of the sampling barrel 200, and each elastic cord 220 is connected to a corresponding connecting ring.

[0039] In this embodiment, a retaining arm 250 is fixedly mounted on the upper end of the sampling barrel 200. This retaining arm 250 provides a mounting location for the hinged rod 241 and wedge 242, guides the upward and downward movement of the piston rod 230, and prevents the piston plate 210 from moving upward and separating from the sampling barrel 200. Preferably, multiple retaining arms 250 are provided, spaced circumferentially around the sampling barrel 200, and define axial holes for the piston rod 230 to pass through between the retaining arms 250. In other embodiments, the upper edge of the sampling barrel 200 may be configured to bend inward to prevent the piston plate 210 from separating from the sampling barrel 200.

[0040] In this embodiment, a discharge port 260 is provided at the bottom of the sampling barrel 200 , and a sealing plug is detachably installed at the discharge port 260 .

[0041] In this embodiment, a hook 310 is connected to the float 300 , and the pull rope 400 is wound around the adjusting wheel 132 and then passes through the hook 310 to be connected to the hinge rod 241 .

[0042] When using the float-based fixed-depth sampling device for polluted water bodies of the present invention, before placing the sampling barrel 200 in water, the outlet 260 is first opened and the piston plate 210 is pressed downward. The piston plate 210 squeezes the air between it and the bottom of the sampling barrel 200, forcing it out through the outlet 260. The elastic cord 220 is then stretched and loaded until the piston plate 210 abuts the bottom of the sampling barrel 200. The wedge 242 of the stopper assembly 240 engages the wedge-shaped groove on the piston column 230, preventing the piston plate 210 from moving upward and returning to its original position. The outlet 260 is then sealed with a sealing plug. After determining the sampling depth, the reel 131 is manually rotated to release the corresponding length of the drawstring 400. The portion of the drawstring 400 extending from the reel 131 is then wound around the wire groove 1325 of the adjustment wheel 132 corresponding to the sampling depth.

[0043] Put the sampling bucket 200 bottom down into the water, slowly loosen the hanging rope 100 to make the sampling bucket 200 move downward under the action of gravity, and at the same time, the float 300 floats on the water surface and is on the backwater side of the hanging rope 100 under the action of water flow. The float 300 overcomes the elastic force of the elastic member 120 under the action of water flow and moves along the sliding frame 110, driving the transmission rod 134 to move synchronously, and the transmission rod 134 drives the transmission wheel 133 to rotate, so that the adjusting wheel 132 rotates and drives the winding wheel 131 to rotate through the pull rope 400 to release the pull rope 400, increasing the float 300 and The length of the pull rope 400 between the stopping components 240 compensates for the error in the actual effective length of the pull rope 400 caused by the movement of the float 300 with the water flow. Then, when the sampling barrel 200 reaches the sampling depth, the pull rope 400 is just tightened, driving the hinged rod 241 to rotate, and the hinged rod 241 drives the wedge block 242 to move and disengage from the wedge groove on the piston column 230, thereby releasing the restriction on the piston column 230. The piston plate 210 moves upward under the tension of the elastic rope 220, and draws water samples into the sampling barrel 200 through the one-way valve 270 at the bottom of the sampling barrel 200.

[0044] After the sampling is completed, the hanging rope 100 is pulled upward to drive the sampling bucket 200 to move upward, and then the sealing plug is opened to discharge the obtained water sample from the discharge port 260.

[0045] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A float fixed depth sampling device for polluted water, characterized by: Includes a lifting rope, sampling bucket, float and pull rope; The sliding sleeve on the lifting rope is provided with a sliding frame, and the floating ball is horizontally slidably installed on the sliding frame and is connected to the sliding frame through an elastic member; a winding unit is provided on the sliding frame; the floating ball floats on the water surface and is located on the backwater side of the lifting rope under the action of the water flow; The sampling barrel is set vertically, with an open top and a sealed bottom. A one-way valve is set at the bottom of the sampling barrel to allow water to flow in. A piston plate is installed in the sampling barrel to slide up and down. The piston plate is connected to the sampling barrel by an elastic rope. The piston plate is connected to the hanging rope by a piston column. A stop assembly is set between the piston column and the sampling barrel to limit the up and down movement of the piston column. One end of the pull rope is connected to the winding unit, and the other end passes through the float and is connected to the stop assembly. The winding unit releases the pull rope when the float moves relative to the suspension rope, and the length of the pull rope between the float and the stop assembly is positively correlated with the distance the float moves. When the sampling barrel reaches the sampling depth, the pull rope is tightened and the stop assembly releases the restriction on the piston column. The stop assembly includes a hinged rod and a wedge block. The hinged rod is perpendicular to the axial direction of the sampling barrel and is hinged to the sampling barrel around a horizontal axis in the middle. One end of the hinged rod is connected to a pull rope, and the other end is connected to the wedge block for sliding along the axial direction of the sampling barrel. The wedge block is installed in the sampling barrel for radial sliding along the sampling barrel. A wedge-shaped groove for cooperating with the wedge block is provided on the outer peripheral wall of the piston column. A torsion spring is connected between the hinged rod and the sampling barrel. The torsion spring forces the wedge block to cooperate with the wedge groove through the hinged rod, thereby limiting the up and down movement of the piston column. When the pull rope is tightened, the hinged rod is driven to rotate, and the hinged rod pulls the wedge block to move and disengage from the wedge groove. The winding unit includes a winding wheel, an adjusting wheel, a transmission wheel and a transmission rod; the winding wheel and the adjusting wheel are both rotatably mounted on the sliding frame, one end of the pull rope is connected to and wound around the winding wheel, then passes through the adjusting wheel and passes through the float to be connected to the hinged rod; the transmission wheel and the adjusting wheel are coaxial and rotate synchronously; the transmission rod is connected to the float and extends along the sliding direction of the float on the sliding frame and cooperates with the transmission wheel; the movement of the float drives the adjusting wheel to rotate through the transmission rod and the transmission wheel, thereby increasing the amount of the pull rope, wherein the cooperation position of the pull rope and the adjusting wheel is tooth meshing; The adjusting wheel includes a central shaft and a sleeve. The central shaft is perpendicular to the transmission rod and parallel to the winding wheel. The central shaft is rotatably installed on the sliding frame, and the transmission wheel is coaxially and fixedly installed on the central shaft. The sleeve is sleeved outside the central shaft and rotates synchronously with the central shaft, and multiple wire grooves with increasing diameters are opened outside the sleeve. The sleeve is replaced with different wire grooves to wrap the pull rope, so that pull ropes of different lengths can be released under the same displacement of the float.

2. The float fixed depth sampling device for polluted water according to claim 1, characterized in that: The regulating wheel is a multi-stage speed-changing wheel, which can change the ratio of its rotation speed to the amount of rope release.

3. The float fixed depth sampling device for polluted water according to claim 2, characterized in that: The adjusting wheel also includes a ball, which is connected to the countersunk hole opened on the inner ring of the sleeve through a spring; a plurality of transmission grooves are opened on the central shaft along its axial direction, and the ball cooperates with different transmission grooves to enable the sleeve to rotate synchronously with the central shaft; the sleeve moves along the central axis so that the ball is stuck in different transmission grooves, so that the wire groove used for winding the pull rope corresponds to the middle part of the reel.

4. The float fixed depth sampling device for polluted water according to claim 1, characterized in that: One end of the elastic rope is connected to the piston plate, and the other end thereof passes upwards over the upper end of the sampling barrel in the sampling barrel and then extends downwards to be connected to the outer wall of the sampling barrel.

5. The float fixed depth sampling device for polluted water according to claim 1, characterized in that: A stop arm is fixedly provided on the upper end of the sampling barrel, which provides an installation position for the hinged rod and the wedge block, guides the up and down movement of the piston column, and prevents the piston plate from moving upward and separating from the sampling barrel.

6. The float constant depth sampling device for polluted water according to claim 1, characterized in that: A discharge port is provided at the bottom of the sampling barrel, and a sealing plug is detachably installed at the discharge port.

7. The float constant depth sampling device for polluted water according to claim 1, characterized in that: A hook is connected to the float, and the pull rope is wound around the adjusting wheel and passes through the hook to be connected to the hinged rod.

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