Bed load sediment transport rate measurer based on riverway desilting

Abstract

The invention relates to the field of river research, in particular to a bed load sediment transport rate measurer based on river channel desilting, which comprises a fixed cylinder, the inner cylinder is connected in the fixed cylinder; an inner cylinder is connected in the fixed cylinder; the inner cylinder is detachably connected with a plurality of spring telescopic rods; all the spring telescopic rods are jointly and fixedly connected with a collecting hopper, and the collecting hopper slides in the inner cylinder. When bed load falls into the collecting hopper, air in the air storage cavity is pressed into the annular cavity through the one-way valve of the vent hole along with downward movement of the collecting hopper, so that the pressure in the annular cavity is continuously increased, and when the pressure reaches a set threshold value of the pressure valve, the pressure valve is instantly opened, so that high-pressure air in the annular cavity enters the annular pipe from the pressure valve; and then the leaves are sprayed to the filter screen from the spray head, so that the leaves covering the filter screen are blown away and washed away along with water flow, and the filter screen is dredged regularly through pressurized air flow.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of river research, and particularly relates to a bed load sediment transport rate measuring device based on river dredging. BACKGROUND

[0002] Bed load sediment transport rate refers to the mass of bed load (i.e. sediment that rolls, slides or jumps along the riverbed) passing through a certain cross-section of a river per unit of time, usually expressed in units of kilograms per second (kg / s) or tons per day (t / d). It is an important parameter for studying river sediment movement, riverbed evolution, reservoir sedimentation, bridge and dike safety, and other engineering problems. Accurate and timely understanding of the sediment transport rate of a river channel is of great significance for studying river dredging, understanding river evolution, soil and water loss prevention, and flood peak capacity estimation.

[0003] For example, the Chinese patent with publication number CN113125107A discloses a bed load sediment transport rate measuring device and method, which can detect the bed load of a laboratory water tank or a river or a coast for a long time in real time and continuously in multiple segments without the need for repeated frequent sampling detection. The device is buried in the riverbed with only the upper surface exposed to the riverbed. Compared with general bed load sediment transport rate measuring devices and methods, it greatly reduces the disturbance to the river surface flow, making the test environment closer to the actual situation.

[0004] However, when the collected bed load is taken out of the river after sampling in the actual river, the flowing river water will interfere with the collected bed load, causing the collected bed load to be lifted and even overflowed with the water flow, resulting in changes in the quality of the collected bed load and inaccurate calculation results. SUMMARY

[0005] In order to overcome the shortcomings of the prior art that the flowing river water will interfere with the collected bed load when the collected bed load is taken out of the river after sampling in the actual river, causing changes in the quality of the collected bed load and inaccurate calculation results, the present application provides a bed load sediment transport rate measuring device based on river dredging.

[0006] The technical scheme is as follows: a bed load sediment transport rate measurer based on river dredging, comprising a fixed cylinder; further comprising an inner cylinder connected in the fixed cylinder; the inner cylinder is detachably connected with a plurality of spring telescopic rods; all the spring telescopic rods are jointly fixed with a collecting hopper, and the collecting hopper slides in the inner cylinder; a displacement sensor is arranged on the lower side of the collecting hopper; the inner cylinder is fixed with a flow guide hopper, and the flow guide hopper is located above the collecting hopper; a filter screen is fixed on the upper end of the inner cylinder, and the filter screen is made of a deformable material; a bottom plate is arranged on the lower end of the inner cylinder; the inner cylinder is provided with an annular cavity; the lower side of the collecting hopper, the upper side of the bottom plate and the inner cylinder jointly form an air storage cavity; a plurality of air vents are arranged in the annular cavity and communicate with the air storage cavity, and each air vent is provided with a one-way valve, and the one-way valve only allows gas to enter the annular cavity from the air storage cavity; the inner cylinder is fixed with an annular pipe, and the annular pipe communicates with the upper end of the annular cavity; the annular pipe is connected with a plurality of nozzles arranged towards the surface of the filter screen; a pressure valve is arranged at the communication position of the annular cavity and the annular pipe; the inner cylinder is connected with a sealing assembly for sealing the inner cylinder.

[0007] As a preferred, the sealing assembly comprises an electric push rod I, a connecting ring, a round rod and a cover plate; the inner cylinder is provided with an annular groove; the inner cylinder is slidably connected with the connecting ring, and the connecting ring slides in the annular groove; the inner cylinder is fixed with the electric push rod I, and the telescopic end of the electric push rod I is fixed with the connecting ring; the connecting ring is fixed with a plurality of round rods; all the round rods are jointly fixed with the cover plate.

[0008] As a preferred, further comprising a spiral strip fixed on the outer side of the fixed cylinder, and the outer surface of the fixed cylinder is rough.

[0009] As a preferred, the collecting hopper is provided with an inclined surface.

[0010] As a preferred, the upper side of the cover plate is conical.

[0011] As a preferred, further comprising a limiting rod; the collecting hopper is fixed with a plurality of limiting rods.

[0012] As a preferred, the limiting rod is inclined downward.

[0013] As a preferred, further comprising a sealing ring; the lower side of the collecting hopper is fixed with the sealing ring, and the sealing ring is in contact with the inner wall of the inner cylinder.

[0014] As a preferred, further comprising an electric push rod II, a push plate and a lifting lug; the fixed cylinder is provided with a sliding groove; the fixed cylinder is fixed with the electric push rod II; the telescopic end of the electric push rod II is fixed with the push plate which slides in the sliding groove, and the push plate is in contact with the bottom plate; the cover plate is fixed with the lifting lug.

[0015] As a preferred, the push plate is provided with a sealing gasket.

[0016] The beneficial effects of the present application are: when the movable load falls into the collecting hopper, the air in the air storage cavity is pressed into the annular cavity through the one-way valve of the air vent as the collecting hopper moves downward, causing the pressure in the annular cavity to continuously increase, when the pressure reaches the set threshold value of the pressure valve, the pressure valve opens instantaneously, so that the high-pressure air in the annular cavity enters the annular pipe from the pressure valve, and then is sprayed from the nozzle towards the filter screen, thereby blowing the leaves covering the filter screen away and being washed away with the water flow, so that the filter screen is periodically dredged by the pressurized air flow.

[0017] The movable load collected in the collecting hopper is limited by the limiting rod, which reduces the amplitude of the movable load being lifted, prevents the movable load from overflowing out of the collecting hopper with the water flow, and at the same time, since the limiting rod is downwardly inclined, it is beneficial to guide the movable load downward into the collecting hopper, and at the same time, the lower end of the limiting rod is closer to the movable load in the collecting hopper, further limiting the lifting amplitude of the movable load, and improving the limiting effect on the movable load.

[0018] When it is necessary to take out the movable load sample collected in the collecting hopper, the electric push rod I drives the cover plate to move downward to close the upper end of the inner cylinder, then the electric push rod II is controlled to drive the push plate to move upward, so that the push plate pushes the inner cylinder and the parts thereon upward out of the fixed cylinder, after the inner cylinder moves to the uppermost end of the fixed cylinder, the operator then hangs the external lifting tool on the lifting lug, pulls the lifting lug upward to separate the bottom plate from the push plate, and then the inner cylinder and the parts thereon are separated from the fixed cylinder, while the fixed cylinder is still fixed on the riverbed, which facilitates the subsequent measurement of re-suiting the inner cylinder and the parts thereon into the fixed cylinder, and after the push plate moves to the upper end of the fixed cylinder, the fixed cylinder is closed to prevent external water flow and sediment from entering the fixed cylinder. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 The structure schematic view of the movable load sediment transport rate measurer based on river dredging disclosed by the present application; Figure 2 The sectional view of the fixed cylinder of the movable load sediment transport rate measurer based on river dredging disclosed by the present application; Figure 3 The combined sectional view of the fixed cylinder and the inner cylinder of the movable load sediment transport rate measurer based on river dredging disclosed by the present application; Figure 4 The three-dimensional structure schematic view of the collecting hopper, the electric push rod I and the connecting ring of the movable load sediment transport rate measurer based on river dredging disclosed by the present application; Figure 5 The three-dimensional structure schematic view of the connecting ring, the round rod, the cover plate and the filter screen of the movable load sediment transport rate measurer based on river dredging disclosed by the present application; Figure 6 The three-dimensional structure schematic view of the filter screen, the annular pipe, the nozzle and the pressure valve of the movable load sediment transport rate measurer based on river dredging disclosed by the present application.

[0020] Explanation of reference numerals in the attached drawings: 1-Fixed cylinder, 2-Spiral strip, 101-Inner cylinder, 102-Spring telescopic rod, 103-Collection hopper, 104-Guide hopper, 105-Electric push rod I, 106-Connecting ring, 107-Round rod, 108-Cover plate, 109-Filter screen, 1010-Annular tube, 1011-Nozzle, 1012-Pressure valve, 1013-Limit rod, 1014-Sealing ring, 301-Electric push rod II, 302-Push plate, 303-Lifting lug, 1001-Slide groove, 11-Bottom plate, 12-Annular groove, 13-Ventilation hole, 14-Annular cavity, 15-Air storage cavity, 33-Sloping part. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0022] Example 1: A bedload transport rate measuring instrument based on river dredging, such as... Figures 1-6 As shown, it includes a fixed cylinder 1; It also includes an inner cylinder 101, spring telescopic rods 102, a collection hopper 103, a guide hopper 104, a filter screen 109, an annular pipe 1010, a nozzle 1011, a pressure valve 1012, and a sealing assembly; the inner cylinder 101 is connected inside the fixed cylinder 1; the inner cylinder 101 is detachably connected to two spring telescopic rods 102; all the spring telescopic rods 102 are fixedly connected to the collection hopper 103, and the collection hopper 103 slides inside the inner cylinder 101; a displacement sensor is provided on the lower side of the collection hopper 103, and the displacement sensor is electrically connected to a data processing center built into the inner cylinder 101, which can calculate the mass of the propelled mass in the inner cylinder 101 based on the signal fed back by the displacement sensor; a funnel-shaped guide hopper 104 is fixedly connected to the inner cylinder 101, and the guide hopper 104 is located above the collection hopper 103; a filter screen is fixedly connected to the upper end of the inner cylinder 101. The filter screen 109 is made of a deformable material; a bottom plate 11 is provided at the lower end of the inner cylinder 101; an annular cavity 14 is provided in the inner cylinder 101; the lower side of the collecting hopper 103, the upper side of the bottom plate 11, and the inner cylinder 101 together form a gas storage cavity 15; the annular cavity 14 has several vent holes 13, which are connected to the gas storage cavity 15, and each vent hole 13 is provided with a one-way valve, which only allows gas to enter the annular cavity 14 from the gas storage cavity 15; an annular pipe 1010 is fixedly connected to the upper end of the inner cylinder 101, and the annular pipe 1010 is connected to the upper end of the annular cavity 14; several nozzles 1011 are connected to the annular pipe 1010, and the nozzles 1011 are oriented towards the mesh surface of the filter screen 109; a pressure valve 1012 is provided at the connection between the annular cavity 14 and the annular pipe 1010; and a sealing assembly is connected to the inner cylinder 101.

[0023] The enclosed assembly includes an electric push rod I 105, a connecting ring 106, round rods 107, and a cover plate 108; the inner cylinder 101 has an annular groove 12; the inner cylinder 101 is slidably connected to the connecting ring 106, and the connecting ring 106 slides within the annular groove 12; the inner cylinder 101 is fixedly connected to the electric push rod I 105, and the telescopic end of the electric push rod I 105 is fixedly connected to the connecting ring 106; the connecting ring 106 is fixedly connected to several round rods 107; all the round rods 107 are jointly fixedly connected to the cover plate 108.

[0024] It also includes a spiral strip 2; the spiral strip 2 is fixed to the outside of the fixed cylinder 1, and the outer surface of the fixed cylinder 1 is roughened.

[0025] The collection hopper 103 is provided with a sloping surface 33, which guides the bedload that falls onto the upper edge of the collection hopper 103 downward into the collection hopper 103, thus preventing the bedload from remaining on the upper edge of the collection hopper 103.

[0026] The upper side of the cover plate 108 is conical, which guides the debris in the river downward and prevents the debris from accumulating on the upper side of the cover plate 108.

[0027] It also includes a limiting rod 1013; several limiting rods 1013 are fixedly connected to the upper side of the collection hopper 103.

[0028] The limit rod 1013 is set at a downward tilt.

[0029] It also includes a sealing ring 1014; the sealing ring 1014 is fixedly connected to the lower side of the collecting hopper 103, and the sealing ring 1014 is in contact with the inner wall of the inner cylinder 101, so as to ensure the airtightness of the gas storage chamber 15 when the collecting hopper 103 slides down along the inner wall of the inner cylinder 101.

[0030] In use, the fixing cylinder 1 of this measuring device is placed in the riverbed of the river channel, with only the upper port of the fixing cylinder 1 exposed above the riverbed, thereby fixing the measuring device to the riverbed. Initially, the cover plate 108 is raised to the highest point, so that the upper port of the inner cylinder 101 is exposed. The bedload (silt) in the riverbed follows the flow of water and enters the guide bucket 104 from the upper port of the inner cylinder 101, and falls down into the collection bucket 103 under the guiding action of the guide bucket 104.

[0031] As the amount of bedload in the collection bucket 103 increases, the mass of the collection bucket 103 increases and it moves downward under its own gravity, causing the collection bucket 103 to compress the spring telescopic rod 102 downward. Since the displacement sensor on the lower side of the collection bucket 103 is electrically connected to the data processing center built into the inner cylinder 101, the data processing center can calculate the mass of the bedload in the inner cylinder 101 based on the signal fed back by the displacement sensor. After the inner cylinder 101 has collected a sufficient mass of bedload, it needs to be removed. At this time, the electric push rod I 105 is controlled to drive the connecting ring 106, the round rod 107 and the cover plate 108 to move downward, so that the cover plate 108 first seals the upper end of the inner cylinder 101 to prevent the external water flow from disturbing the bedload already collected in the collection bucket 103 when the measuring device is removed from the riverbed, causing the bedload to overflow with the water flow. Then, the operator removes the measuring device from the riverbed and then removes the bedload collected in the inner cylinder 101.

[0032] By setting a spiral strip 2 on the outside of the fixing cylinder 1, the operator can easily screw the fixing cylinder 1 into the riverbed for fixation by rotating the fixing cylinder 1. In addition, the outer surface of the fixing cylinder 1 is roughened to increase the friction between the fixing cylinder 1 and the riverbed after the fixing cylinder 1 is fixed to the riverbed, thereby increasing the fixing effect of the fixing cylinder 1 and preventing the fixing cylinder 1 from sinking.

[0033] Considering that when conducting measurements in shallow water areas, there will be a lot of debris such as leaves and branches on the riverbed, which will also enter the inner cylinder 101 with the water flow and affect the collection of bedload, a filter screen 109 is installed at the upper end of the inner cylinder 101 to intercept debris in the riverbed and prevent debris such as leaves and branches from entering the inner cylinder 101 with the bedload and affecting the measurement results.

[0034] To prevent accidental loss of bedload during collection, a limiting rod 1013 is used to limit the bedload already collected in the collection hopper 103, reducing the amplitude of the bedload being lifted and preventing the bedload from overflowing the collection hopper 103 with the water flow. At the same time, since the limiting rod 1013 is set to a downward inclination, it is beneficial to guide the bedload downward into the collection hopper 103. At the same time, the lower end of the limiting rod 1013 is closer to the bedload in the collection hopper 103, further limiting the amplitude of the bedload being lifted and improving the limiting effect on the bedload.

[0035] Considering that there are many large debris such as leaves and branches at the bottom of the shallow water area of ​​the river, although the filter screen 109 can block the debris to prevent it from directly entering the inner cylinder 101, these large debris will also cover the filter screen 109 while being intercepted, causing the filter screen 109 to become clogged and affecting the subsequent entry of the propellant into the inner cylinder 101. To solve this problem, a protective rod composed of several round rods 107 is used to block the large debris such as leaves and branches. However, some small leaves will still cover the filter screen 109 through the gaps in the round rods 107. Therefore, when the propellant falls into the collection hopper 103, as the collection hopper 103 gradually moves downward, the collection hopper 103 forces the air in the air storage chamber 15 into the annular chamber 14 through the one-way valve of the vent hole 13, increasing the pressure in the annular chamber 14. When the air pressure in the annular chamber 14 increases to the pressure valve 1, When the set threshold of 012 is reached, the pressure valve 1012 opens, allowing high-pressure air in the annular cavity 14 to enter the annular pipe 1010 through the pressure valve 1012, and then spray it from the nozzle 1011 onto the filter screen 109, thereby blowing away the leaves covering the filter screen 109 and washing them away with the water flow. In this way, the filter screen 109 is periodically cleaned by pressurized airflow. It should be noted that since the collection bucket 103 will gradually move down throughout the entire measurement and sampling cycle, the collection bucket 103 will continuously pressurize the air in the air storage chamber 15 into the annular cavity 14 through the one-way valve of the vent hole 13. Only when the air pressure in the annular cavity 14 reaches the threshold of the pressure valve 1012 will the pressurized air be released to periodically clean the filter screen 109, ensuring the unobstructed flow of the filter screen 109 throughout the entire measurement and sampling cycle. The air in the air storage chamber 15 can be replenished when the inner cylinder 101 is removed later.

[0036] The measurement steps of this bedload transport rate measuring instrument based on river dredging are as follows: 1) The collecting hopper 103 receives the bedload flowing down from the guide hopper 104. As the mass of the bedload in the collecting hopper 103 gradually increases, the collecting hopper 103 compresses downward against the spring telescopic rod 102, causing a change in the displacement of the collecting hopper 103. The displacement sensor on the lower side of the collecting hopper 103 receives the displacement signal. The data processing center built into the inner cylinder 101 calculates the mass of the bedload in the inner cylinder 101 based on the signal fed back by the displacement sensor. Then, the bedload transport rate is obtained by dividing the mass of the bedload falling into the collecting hopper 103 per unit time by the inner diameter (i.e., the sampling width) of the upper port of the guide hopper 104. ; 2) After a certain period of time, the bedload in the collection bucket 103 is taken out, dried, weighed, and the bedload transport rate Gs is calculated; 3) Divide the bedload transport rate obtained in step 2 by the bedload transport equivalent rate obtained in step 1 to obtain the correction coefficient m; 4) For a bedload transport rate measuring instrument of a certain specification, by... The bedload transport rate is thus obtained; where M is the mass of bedload collected by the measuring instrument within a certain time period. d is the diameter of the upper port of the guide bucket 104; t represents time.

[0037] Example 2, based on Example 1, such as Figures 2-4 As shown, it also includes an electric push rod II 301, a push plate 302, and a lifting lug 303; the fixed cylinder 1 has a sliding groove 1001; the fixed cylinder 1 is bolted to the electric push rod II 301; the extension end of the electric push rod II 301 is fixedly connected to the push plate 302, and the push plate 302 slides in the sliding groove 1001 and contacts the bottom plate 11; the cover plate 108 is fixedly connected to the lifting lug 303.

[0038] A sealing gasket is provided on the upper side of the push plate 302.

[0039] Considering that in Example 1, when the bedload sample collected in the collection hopper 103 is removed, the entire measuring device needs to be taken out of the riverbed, and the measuring device needs to be fixed back to the riverbed for subsequent measurements, which increases the workload, when the bedload sample collected in the collection hopper 103 needs to be removed, the electric push rod I 105 drives the cover plate 108 to move down to close the upper end of the inner cylinder 101, and then controls the electric push rod II 301 to drive the push plate 302 to move up, so that the push plate 302 pushes the inner cylinder 101 and its parts upward. After the inner cylinder 101 moves to the top of the fixed cylinder 1, the operator hangs the external lifting device on the lifting lug 303 and pulls the lifting lug 303 upward to separate the bottom plate 11 from the push plate 302. Then the inner cylinder 101 and its parts are removed from the fixed cylinder 1, while the fixed cylinder 1 remains fixed on the riverbed. This makes it convenient to put the inner cylinder 101 and its parts back into the fixed cylinder 1 for subsequent measurements. After the push plate 302 moves up to the top of the fixed cylinder 1, it seals the fixed cylinder 1 to prevent external water flow and silt from entering the fixed cylinder 1.

[0040] Furthermore, when the inner cylinder 101 is removed, after the push plate 302 closes the fixed cylinder 1, the sealing gasket on the upper side of the push plate 302 improves the sealing between the push plate 302 and the fixed cylinder 1, preventing external water from entering the fixed cylinder 1 through the gap between the push plate 302 and the fixed cylinder 1.

[0041] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A bedload transport rate measuring instrument based on river dredging, comprising a fixed cylinder (1); characterized in that: It also includes an inner cylinder (101) connected to a fixed cylinder (1); the inner cylinder (101) is detachably connected to several spring telescopic rods (102); all the spring telescopic rods (102) are fixedly connected to a collection hopper (103), and the collection hopper (103) slides inside the inner cylinder (101); a displacement sensor is provided on the lower side of the collection hopper (103); a guide hopper (104) is fixedly connected to the inner cylinder (101), and the guide hopper (104) is located above the collection hopper (103); a filter screen (109) is fixedly connected to the upper end of the inner cylinder (101), and the filter screen (109) is made of a deformable material; a bottom plate (11) is provided at the lower end of the inner cylinder (101); the inner cylinder (101) has an annular cavity (14); the collection hopper (103) is located on the lower side, the bottom plate (11) is located on the upper side, and the bottom plate (11) is located on the upper side. The inner wall of the inner cylinder (101) together forms a gas storage chamber (15); the annular cavity (14) is provided with several vent holes (13), and the vent holes (13) are connected to the gas storage chamber (15), and each vent hole (13) is provided with a one-way valve, which only allows gas to enter the annular cavity (14) from the gas storage chamber (15); the inner cylinder (101) is fixedly connected to an annular pipe (1010), and the annular pipe (1010) is connected to the upper end of the annular cavity (14); the annular pipe (1010) is connected to several nozzles (1011) facing the mesh surface of the filter screen (109); a pressure valve (1012) is provided at the connection between the annular cavity (14) and the annular pipe (1010); the inner cylinder (101) is connected to a sealing component for sealing the inner cylinder (101).

2. The bedload transport rate measuring instrument based on river dredging according to claim 1, characterized in that, The enclosed assembly includes an electric push rod I (105), a connecting ring (106), round rods (107), and a cover plate (108); the inner cylinder (101) has an annular groove (12); the inner cylinder (101) is slidably connected to the connecting ring (106), and the connecting ring (106) slides in the annular groove (12); the inner cylinder (101) is fixedly connected to the electric push rod I (105), and the telescopic end of the electric push rod I (105) is fixedly connected to the connecting ring (106); the connecting ring (106) is fixedly connected to several round rods (107); all the round rods (107) are together fixedly connected to the cover plate (108).

3. The bedload transport rate measuring instrument based on river dredging according to claim 1, characterized in that, It also includes a spiral strip (2) fixed to the outside of the fixed cylinder (1), and the outer surface of the fixed cylinder (1) is rough.

4. The bedload transport rate measuring instrument based on river dredging according to claim 1, characterized in that, The collection hopper (103) is provided with a sloping surface (33).

5. A bedload transport rate measuring instrument based on river dredging according to claim 2, characterized in that, The upper side of the cover plate (108) is conical.

6. A bedload transport rate measuring instrument based on river dredging according to claim 1, characterized in that, It also includes limit rods (1013); the collection hopper (103) is fixedly connected with several limit rods (1013).

7. A bedload transport rate measuring instrument based on river dredging according to claim 6, characterized in that, The limit rod (1013) is set at a downward angle.

8. A bedload transport rate measuring instrument based on river dredging according to claim 1, characterized in that, It also includes a sealing ring (1014); the sealing ring (1014) is fixedly connected to the lower side of the collection hopper (103), and the sealing ring (1014) is in contact with the inner wall of the inner cylinder (101).

9. A bedload transport rate measuring instrument based on river dredging according to claim 2, characterized in that, It also includes an electric push rod II (301), a push plate (302) and a lifting lug (303); the fixed cylinder (1) has a sliding groove (1001); the fixed cylinder (1) is fixedly connected to the electric push rod II (301); the telescopic end of the electric push rod II (301) is fixedly connected to the push plate (302) that slides in the sliding groove (1001), and the push plate (302) is in contact with the bottom plate (11); the cover plate (108) is fixedly connected to the lifting lug (303).

10. A bedload transport rate measuring instrument based on river dredging according to claim 9, characterized in that, The push plate (302) is equipped with a sealing gasket.

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