A manual sampling and testing device specifically designed for large drainage culverts.

Abstract

This invention belongs to the field of environmental monitoring technology, specifically a manual sampling and testing device for large drainage culverts, comprising a three-way flexible hose; one end of the three-way flexible hose is connected to a manual syringe, and the other two ends of the three-way flexible hose are respectively connected to a first one-way valve and a second one-way valve; the end of the first one-way valve away from the manual syringe is connected to a thickened PVC transparent flexible hose; by observing the relative position of the front end of the sampling inlet pipe to the liquid level with the help of a pipe endoscope, the front end of the sampling inlet pipe is accurately inserted into the liquid surface, and then the manual syringe is repeatedly pushed and pulled to first expel the air in the sampling inlet pipe and form a negative pressure environment. At this time, under the action of atmospheric pressure, the sewage in the drainage culvert flows into the three-way flexible hose through the second one-way valve, then through the first one-way valve into the thickened PVC transparent flexible hose, and finally into the sampling and testing bottle.

Description

Technical Field

[0001] This invention belongs to the field of environmental monitoring technology, specifically a manual sampling and testing device for large drainage pipe culverts. Background Technology

[0002] In current urban drainage systems, large drainage culverts are typically buried 7-10 meters below roads. These culverts experience high flow velocities (>1m / s) and deep liquid levels, and are only ventilated to the outside environment through ventilation holes no larger than 2cm in diameter at the top of inspection wells. These characteristics create the following technical problems:

[0003] Unable to use electric equipment: Because the drainage culvert is located in the middle of the green belt or under the roadway, there is no power supply on site, so electric water pumps cannot be used; and the suction lift of self-priming pumps is generally only 3-5 meters, which is not enough to pump water up from a depth of 10 meters underground.

[0004] Significant safety hazards: To avoid traffic and personnel safety issues, it is not allowed to open the manhole cover for sampling. Therefore, sampling can only be carried out through the small hole on the manhole cover that allows ventilation to the outside.

[0005] Liquid level not visible: The light inside the drainage pipe culvert is extremely poor, making it impossible to directly observe the liquid level, which leads to sampling failure. Therefore, there is an urgent need for a device that can safely and accurately complete sampling through a small-diameter hole in situations where there is no electricity, deep burial, fast flow rate, and the liquid level is not visible. To this end, the present invention provides a manual sampling and detection device specifically for large drainage pipe culverts. Summary of the Invention

[0006] In order to overcome the shortcomings of the prior art, at least one technical problem raised in the background art is solved.

[0007] The technical solution adopted by this invention to solve its technical problem is as follows: A manual sampling and testing device specifically for large drainage pipe culverts, comprising a three-way flexible hose; one end of the three-way flexible hose is connected to a manual syringe (50-200ml), and the other two ends of the three-way flexible hose are respectively connected to a first one-way valve and a second one-way valve; the end of the first one-way valve away from the manual syringe is connected to a thickened PVC transparent flexible hose (outer diameter 6-10mm), and the end of the thickened PVC transparent flexible hose away from the first one-way valve is connected to a sampling and testing bottle, the sampling and testing bottle being connected to an atmospheric connection pipe (for venting during water sampling); the end of the second one-way valve away from the first one-way valve is connected to a sampling inlet pipe, and a pipe endoscope (diameter 8mm) is fixedly installed on the side wall of the sampling inlet pipe near the inlet end, the pipe endoscope being electrically connected to a display via wires, and a set of fixing rings being fixedly connected to the side wall of the sampling inlet pipe, the fixing rings being used to connect to the wires.

[0008] A manual pressure relief valve is installed near the second one-way valve on the sampling inlet pipe. A counterweight pipe (with a diameter of less than 20 mm) is connected to one end of the sampling inlet pipe near the endoscope. The counterweight pipe is made of corrosion-resistant metal material to ensure that it will not be corroded by sewage during long-term use.

[0009] A filter is provided at the front end of the counterweight tube. The filter includes a housing and a filter screen. The housing is fixedly connected to the side wall of the counterweight tube. The filter screen is placed inside the housing. The diameter of the housing is less than 20mm.

[0010] The sampling inlet pipe is configured in multiple sections, and each section is connected by a pipe extension connector. The endoscope is fixedly installed on the sampling inlet pipe at the very end, and the sampling inlet pipe at the very top is connected to the second one-way valve.

[0011] A connecting plate is fixedly connected to the inner wall of the outer casing. A rotating connecting shaft is provided on the bottom surface of the connecting plate. A rectangular plate is fixedly connected to the side wall of the connecting shaft. A set of brush bristles is fixedly connected to the bottom surface of the rectangular plate. The brush bristles are used to clean the filter screen. A set of drive blades is fixedly connected to the outer wall of the connecting shaft.

[0012] The bottom surface of the connecting plate is rotatably connected to a circular shaft, the bottom end of the circular shaft is open, the connecting shaft is slidably connected to the inner wall of the circular shaft, the rectangular plate has a hollow structure inside, the side wall of the connecting shaft has a connecting groove communicating with the inside of the rectangular plate, and the bottom surface of the rectangular plate has a set of circular holes.

[0013] A ring is fixedly connected to the inner wall of the outer shell. A set of first springs is fixedly connected to the top surface of the ring. A connecting ring is fixedly connected to the end of the first spring away from the ring. The filter screen is fixed to the inner wall of the connecting ring. A set of magnetic sheets is fixedly connected to the bottom surface of the filter screen. The rectangular plate is made of magnetic material and is magnetically attracted to the magnetic sheets.

[0014] The connecting ring has a hollow structure inside, and a set of annularly distributed through grooves are opened on the inner wall of the connecting ring. A water-propulsion component is installed inside the connecting ring.

[0015] The pushing assembly includes a push ring that is slidably connected to the inner wall of the connecting ring. A set of second springs is fixedly connected between the bottom surface of the push ring and the inner wall of the connecting ring. A pair of connecting rods are slidably connected to the top surface of the connecting ring, and the bottom surface of the connecting rods is fixedly connected to the push ring.

[0016] The beneficial effects of this invention are as follows:

[0017] 1. This invention involves lowering a sampling inlet pipe into a drainage culvert 10 meters underground. During this process, an endoscope is used to observe the relative position of the sampling inlet pipe tip to the liquid level, ensuring the tip of the pipe accurately reaches the liquid surface. Then, a manual syringe is repeatedly pushed and pulled to expel air from the pipe, creating a negative pressure environment. Under atmospheric pressure, sewage from the culvert flows through a second one-way valve into a three-way flexible hose, then through a first one-way valve into a thickened PVC transparent flexible hose, and finally into a sampling and testing bottle. Thus, under complex conditions such as no electricity, deep burial, high flow rate, and invisible liquid level, sewage sampling from large drainage culverts can be safely and accurately completed through small-diameter vent holes on the manhole cover.

[0018] 2. When the present invention samples sewage, the sewage passes through the outer shell. At this time, the water flow drives the drive blade to rotate, which in turn drives the connecting shaft to rotate, causing the rectangular plate to rotate. The bristles then rotate with the rectangular plate, thus cleaning the filter screen. In this way, the filter screen can be continuously cleaned. Attached Figure Description

[0019] The invention will now be further described with reference to the accompanying drawings.

[0020] Figure 1 This is a schematic diagram of the sampling and detection device in this invention;

[0021] Figure 2 This is a schematic diagram of the outer shell structure in this invention;

[0022] Figure 3 This is a schematic diagram of the internal structure of the outer shell in this invention;

[0023] Figure 4 yes Figure 3 Enlarged view of point A;

[0024] Figure 5 yes Figure 3 Enlarged view of point B.

[0025] In the diagram: 1. Sampling and testing bottle; 2. Atmospheric connection pipe; 3. First one-way valve; 4. Second one-way valve; 5. Syringe; 6. Manual pressure relief valve; 7. Pipe extension connector; 8. Fixing ring; 9. Counterweight pipe; 10. Pipe endoscope; 11. Filter; 12. Thickened PVC transparent flexible tube; 13. Sampling inlet pipe; 14. Monitor; 15. T-shaped flexible tube; 16. Housing; 17. Filter screen; 18. Connecting plate; 19. Connecting shaft; 20. Drive blade; 21. Rectangular plate; 22. Brush bristles; 23. Round shaft; 24. Connecting groove; 25. Round hole; 26. Connecting ring; 27. Magnetic sheet; 28. Circular ring; 29. ​​Push ring; 30. Through groove; 31. Connecting rod. Detailed Implementation

[0026] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0027] Example 1: As Figure 1 As shown in the embodiment of the present invention, a manual sampling and testing device specifically for large drainage pipe culverts includes a three-way flexible hose 15; one end of the three-way flexible hose 15 is connected to a manual syringe 5 (50-200ml), and the other two ends of the three-way flexible hose 15 are respectively connected to a first one-way valve 3 and a second one-way valve 4; the end of the first one-way valve 3 away from the manual syringe 5 is connected to a PVC thickened transparent flexible hose 12 (outer diameter 6-10mm), and the end of the PVC thickened transparent flexible hose 12 away from the first one-way valve 3 is connected to a sampling and testing bottle 1, and the sampling and testing bottle 1 is connected to an atmospheric connection pipe 2 (for venting when taking water samples); the end of the second one-way valve 4 away from the first one-way valve 3 is connected to a sampling inlet pipe 13, and a pipe endoscope 10 (diameter 8mm) is fixedly installed on the side wall of the sampling inlet pipe 13 near the inlet end, the pipe endoscope 10 is electrically connected to a display 14 through wires, and a set of fixing rings 8 are fixedly connected to the side wall of the sampling inlet pipe 13, the fixing rings 8 being used to connect to the wires.

[0028] The first one-way valve 3 and the second one-way valve 4 are low-opening-pressure one-way check valves to ensure unidirectional liquid flow even under low pressure. The atmospheric connection pipe 2 is used to discharge gas from the sampling test bottle 1 when taking water samples. The operator first inspects the manhole cover for ventilation holes, and then slowly lowers the sampling inlet pipe 13 through the ventilation holes of the manhole cover until it reaches a depth of 10 meters into the drainage culvert. During this process, the operator uses the pipe endoscope 10 to observe the relative position of the front end of the sampling inlet pipe 13 to the liquid level and adjusts the lowering position and depth of the sampling inlet pipe 13 to ensure that the front end of the sampling inlet pipe 13 accurately reaches the liquid surface. Once the position of the inlet pipe is adjusted, the sampling operation begins. The manual syringe 5 is repeatedly pushed and pulled to first expel the air from the sampling inlet pipe 13 and create a negative pressure environment. At this time, under the action of atmospheric pressure, the sewage in the drainage culvert flows into the three-way hose 15 through the second one-way valve 4. Then, it passes through the first one-way valve 3 and enters the PVC thickened transparent hose 12, and finally enters the sampling and testing bottle 1. Due to the one-way check valve characteristics of the first one-way valve 3 and the second one-way valve 4, the sewage can only flow from the drainage pipe to the testing bottle and there will be no backflow. Through the above specific implementation method, the manual sampling device of the present invention can safely and accurately complete the sampling of sewage in large drainage pipes under complex conditions such as no electricity, deep burial, fast flow rate and invisible liquid level, through the small diameter vent hole on the manhole cover.

[0029] A manual pressure relief valve 6 is installed near the second one-way valve 4 on the sampling inlet pipe 13. A counterweight pipe 9 (diameter less than 20mm) is connected to one end of the sampling inlet pipe 13 near the pipe endoscope 10. The counterweight pipe 9 is made of corrosion-resistant metal material to ensure that it will not be corroded by sewage during long-term use. If multiple sampling is required, after each sampling is completed, the manual pressure relief valve 6 is opened to drain the sewage in the inlet pipe to prevent residual sewage from mixing with the next sample and causing contamination. After draining the sewage, the manual pressure relief valve 6 is closed, and the manual syringe 5 is pushed and pulled again to complete the next sampling. The counterweight pipe 9 is installed at the front end of the sampling inlet pipe 13 to ensure that the sampling inlet pipe 13 can pass smoothly through the inspection well vent and sink to the bottom of the culvert.

[0030] A filter 11 is provided at the front end of the counterweight pipe 9. The filter 11 includes a housing 16 and a filter screen 17. The housing 16 is fixedly connected to the side wall of the counterweight pipe 9. The filter screen 17 is disposed inside the housing 16. The diameter of the housing 16 is less than 20 mm. When water enters the sampling inlet pipe 13 in this application, the water will pass through the filter screen 17 in the filter 11, so that the impurities in the water are blocked by the filter screen 17, so as to prevent the impurities in the sewage in the drainage pipe from entering the sampling inlet pipe 13 and causing the sampling inlet pipe 13 to be blocked.

[0031] The sampling inlet pipe 13 is configured in multiple segments, and each segment of the sampling inlet pipe 13 is connected by a pipe extension connector 7. The pipe endoscope 10 is fixedly installed on the sampling inlet pipe 13 at the very end, and the sampling inlet pipe 13 at the very top is connected to the second one-way valve 4. By designing the sampling inlet pipe 13 in multiple segments, this application allows for the selection of an appropriate number of segments according to large drainage culverts of different depths, and the segments are connected by the pipe extension connector 7, thereby enabling the device to be used in large drainage culverts of different depths.

[0032] Example 2: Figures 1 to 5As shown in the comparative embodiment one, another embodiment of the present invention is as follows: a connecting plate 18 is fixedly connected to the inner wall of the outer shell 16, a rotating connecting shaft 19 is provided on the bottom surface of the connecting plate 18, a rectangular plate 21 is fixedly connected to the side wall of the connecting shaft 19, a set of bristles 22 is fixedly connected to the bottom surface of the rectangular plate 21, the bristles 22 are used to clean the filter screen 17, and a set of drive blades 20 is fixedly connected to the outer wall of the connecting shaft 19. When the sewage is sampled, the sewage will pass through the filter screen 17. After long-term use, impurities will accumulate on the filter screen 17, causing the filter screen 17 to become clogged, which will affect the sampling of sewage. With the above mechanism, when the sewage is sampled, the sewage will pass through the outer shell 16. At this time, the water flow will drive the drive blades 20 to rotate, thereby causing the drive blades 20 to drive the connecting shaft 19 to rotate, so that the rectangular plate 21 will rotate. At this time, the bristles 22 will rotate with the rectangular plate 21, thereby allowing the bristles 22 to clean the filter screen 17. In this way, the filter screen 17 can be continuously cleaned.

[0033] A circular shaft 23 is rotatably connected to the bottom surface of the connecting plate 18. The bottom end of the circular shaft 23 is open. The connecting shaft 19 is slidably connected to the inner wall of the circular shaft 23. The rectangular plate 21 has a hollow internal structure. A connecting groove 24 communicating with the inside of the rectangular plate 21 is opened on the side wall of the connecting shaft 19. A set of circular holes 25 are opened on the bottom surface of the rectangular plate 21. In this application, when sampling, it is necessary to repeatedly push and pull the manual syringe 5. At this time, liquid will intermittently enter the outer shell 16. When the liquid enters, the fan blades are propelled by the water flow, causing the connecting shaft 19 to slide towards the side closer to the round shaft 23. Since the round hole 25 is open, the round shaft 23 will be filled with water. When the connecting shaft 19 slides, it will push this part of the water, allowing the water to enter the rectangular plate 21 from the connecting groove 24, and then spray out from the round hole 25 onto the bristles 22 to refresh the bristles 22. When the liquid enters the housing 16, the connecting shaft 19 will slide down and reset due to gravity.

[0034] A ring 28 is fixedly connected to the inner wall of the outer shell 16. A set of first springs is fixedly connected to the top surface of the ring 28. A connecting ring 26 is fixedly connected to the end of the first spring away from the ring 28. The filter screen 17 is fixed on the inner wall of the connecting ring 26. A set of magnetic sheets 27 is fixedly connected to the bottom surface of the filter screen 17. The rectangular plate 21 is made of magnetic material, and the rectangular plate 21 and the magnetic sheets 27 are magnetically attracted to each other.

[0035] When the connecting shaft 19 rotates, the rectangular plate 21 rotates synchronously. At this time, the rectangular plate 21 passes the magnetic sheet 27. When the magnetic sheet 27 is attracted, it will drive the filter screen 17 to move upward, thereby driving the connecting ring 26 to move upward. This will make the filter screen 17 fit more closely with the bristles 22, thereby improving the cleaning effect of the bristles 22 on the filter screen 17. When the rectangular plate 21 passes the magnetic sheet 27, the first spring will pull the connecting ring 26 downward. At the same time, due to its elasticity, the first spring can drive the connecting ring 26 to shake, thereby causing the filter screen 17 to shake and shake off the impurities on the filter screen 17, thereby further improving the cleaning effect on the filter screen 17.

[0036] The connecting ring 26 has a hollow structure inside, and a set of annularly distributed through grooves 30 are opened on the inner wall of the connecting ring 26. A water-pushing component is provided inside the connecting ring 26. When water is sampled, water will enter the connecting ring 26 from the through grooves 30. At this time, the water in the connecting ring 26 can be pushed by the pushing component, so that the water is sprayed out from the through grooves 30 to the bottom surface of the filter screen 17, so as to further clean and unclog the filter screen 17.

[0037] The pushing assembly includes a push ring 29 slidably connected to the inner wall of the connecting ring 26. A set of second springs is fixedly connected between the bottom surface of the push ring 29 and the inner wall of the connecting ring 26. A pair of connecting rods 31 are slidably connected to the top surface of the connecting ring 26. The bottom surface of the connecting rods 31 is fixedly connected to the push ring 29. When the connecting ring 26 moves upward, the connecting rods 31 are pushed by the connecting plate 18. At this time, the connecting rods 31 push the push ring 29, causing the push ring 29 to push the water in the connecting ring 26, thereby allowing the water to spray out from the channel 30 to the bottom surface of the filter screen 17 to unclog the filter screen 17.

[0038] Working principle: The operator first inspects the vent on the manhole cover, then slowly lowers the sampling inlet pipe 13 through the vent until it reaches a depth of 10 meters inside the drainage culvert. During this process, the operator uses a pipe endoscope 10 to observe the relative position of the tip of the sampling inlet pipe 13 to the liquid level, adjusting the lowering position and depth of the sampling inlet pipe 13 to ensure the tip accurately reaches the liquid surface. Once the inlet pipe is positioned correctly, sampling begins. The operator repeatedly pushes and pulls the manual syringe 5 to expel air from the sampling inlet pipe 13, creating a negative pressure environment. At this point, under atmospheric pressure, the sewage in the drainage culvert flows through the second one-way valve 4 into the three-way flexible hose 15. Then, it passes through the first one-way valve 3 and enters the PVC thickened transparent hose 12, and finally enters the sampling and testing bottle 1. Due to the one-way check valve characteristics of the first one-way valve 3 and the second one-way valve 4, the sewage can only flow from the drainage pipe to the testing bottle and there will be no backflow. Through the above specific implementation method, the manual sampling device of the present invention can safely and accurately complete the sampling of sewage in large drainage pipes under complex conditions such as no electricity, deep burial, fast flow rate and invisible liquid level, through the small diameter vent hole on the manhole cover.

[0039] Meanwhile, when the sewage is sampled, it passes through the filter screen 17. Over time, impurities will accumulate on the filter screen 17, causing it to become clogged and affecting the sewage sampling. When the sewage is sampled by the above mechanism, it passes through the outer shell 16. At this time, the water flow drives the drive blade 20 to rotate, which in turn drives the connecting shaft 19 to rotate, causing the rectangular plate 21 to rotate. The bristles 22 will then rotate with the rectangular plate 21, thus cleaning the filter screen 17. In this way, the filter screen 17 can be continuously cleaned.

[0040] The terms "front," "back," "left," "right," "top," and "bottom" all refer to the figures in the accompanying drawings. Figure 1 Based on the perspective of the observer, the side of the device facing the observer is defined as the front, the left side of the observer is defined as the left, and so on.

[0041] In the description of this invention, it should be understood that the terms "center", "longitudinal", "lateral", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this invention.

[0042] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A manual sampling and testing device specifically designed for large drainage culverts, comprising a three-way flexible hose (15); characterized in that: One end of the three-way hose (15) is connected to a manual syringe (5), and the other two ends of the three-way hose (15) are respectively connected to a first check valve (3) and a second check valve (4). The end of the first one-way valve (3) away from the manual syringe (5) is connected to a PVC thickened transparent tube (12), and the end of the PVC thickened transparent tube (12) away from the first one-way valve (3) is connected to a sampling test bottle (1). The sampling test bottle (1) is connected to an atmospheric connection tube (2). The second one-way valve (4) is connected to a sampling inlet pipe (13) at one end away from the first one-way valve (3). A pipe endoscope (10) is fixedly installed on the side wall of the sampling inlet pipe (13) near the inlet end. The pipe endoscope (10) is electrically connected to a display (14) via a wire. A set of fixing rings (8) is fixedly connected to the side wall of the sampling inlet pipe (13). The fixing rings (8) are connected by wires. The sampling inlet pipe (13) is connected to a counterweight pipe (9) at one end near the endoscope (10). The front end of the counterweight tube (9) is provided with a filter (11), the filter (11) includes a shell (16) and a filter screen (17), the shell (16) is fixedly connected to the side wall of the counterweight tube (9), and the filter screen (17) is disposed inside the shell (16); A connecting plate (18) is fixedly connected to the inner wall of the outer shell (16). A rotating connecting shaft (19) is provided on the bottom surface of the connecting plate (18). A rectangular plate (21) is fixedly connected to the side wall of the connecting shaft (19). A set of brush bristles (22) is fixedly connected to the bottom surface of the rectangular plate (21). The brush bristles (22) are used to clean the filter screen (17). A set of drive blades (20) is fixedly connected to the outer wall of the connecting shaft (19). The bottom surface of the connecting plate (18) is rotatably connected to a round shaft (23), the bottom end of the round shaft (23) is open, the connecting shaft (19) is sealed and slidably connected to the inner wall of the round shaft (23), the rectangular plate (21) is hollow inside, the side wall of the connecting shaft (19) is provided with a connecting groove (24) communicating with the inside of the rectangular plate (21), and the bottom surface of the rectangular plate (21) is provided with a set of round holes (25). The inner wall of the outer shell (16) is fixedly connected to a ring (28), and a set of first springs is fixedly connected to the top surface of the ring (28). A connecting ring (26) is fixedly connected to the end of the first spring away from the ring (28). The filter screen (17) is fixed on the inner wall of the connecting ring (26). A set of magnetic sheets (27) is fixedly connected to the bottom surface of the filter screen (17). The rectangular plate (21) is made of magnetic material, and the rectangular plate (21) and the magnetic sheets (27) are magnetically attracted to each other.

2. The manual sampling and testing device specifically designed for large drainage culverts according to claim 1, characterized in that: The sampling inlet pipe (13) is equipped with a manual pressure relief valve (6) near the second one-way valve (4), and the counterweight pipe (9) is made of corrosion-resistant metal material.

3. The manual sampling and testing device specifically designed for large drainage culverts according to claim 2, characterized in that: The diameter of the outer shell (16) is less than 20 mm.

4. The manual sampling and testing device specifically designed for large drainage culverts according to claim 1, characterized in that: The sampling inlet pipe (13) is set in multiple sections. Each section of the sampling inlet pipe (13) is connected by a pipe extension connector (7). The pipe endoscope (10) is fixedly installed on the sampling inlet pipe (13) at the very end. The sampling inlet pipe (13) at the very top is connected to the second one-way valve (4).

5. A manual sampling and testing device specifically designed for large drainage culverts according to claim 1, characterized in that: The connecting ring (26) has a hollow structure inside. A set of annularly distributed through grooves (30) are opened on the inner wall of the connecting ring (26). A water-pushing component is provided inside the connecting ring (26).

6. A manual sampling and testing device specifically designed for large drainage culverts according to claim 5, characterized in that: The pushing assembly includes a push ring (29) that is slidably connected to the inner wall of the connecting ring (26). A set of second springs is fixedly connected between the bottom surface of the push ring (29) and the inner wall of the connecting ring (26). A pair of connecting rods (31) are slidably connected to the top surface of the connecting ring (26). The bottom surface of the connecting rods (31) is fixedly connected to the push ring (29).

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