Vacuum breaking water stop valve

Abstract

The utility model provides a vacuum breaking water stop valve. The vacuum breaking water stop valve comprises a valve body and a partition plate. The partition plate divides the internal space of the valve body into an air outlet channel and an air inlet channel, an outlet of the air outlet channel is located on one side of the bottom of the valve body, and an inlet of the air inlet channel is located on the other side of the top of the valve body. A connecting channel opening for communicating the air inlet channel with the air outlet channel is formed in the partition plate; a water return hole is formed in one side, close to the bottom of the valve body, of the partition plate; a floater is arranged below the connecting channel opening, and a connecting rod penetrating through the connecting channel opening is arranged above the floater; a vacuum breaking chamber is arranged at the top of the valve body, a vent hole is formed in a shell of the vacuum breaking chamber, and a connecting rod inlet and a sealing module for sealing the connecting rod inlet are arranged at the bottom of the vacuum breaking chamber; the upper end of the connecting rod penetrates through the connecting rod inlet and is fixedly connected with the sealing module. In the using process, vacuum breaking and water stopping can be automatically and rapidly achieved, water or other liquid is effectively prevented from damaging the liquid ring pump, and therefore the reliability of vacuum water diversion equipment is improved, and the service life of the vacuum water diversion equipment is prolonged.

Description

Technical Field

[0001] This utility model belongs to the technical field of vacuum water priming equipment, and specifically relates to a vacuum breaking stop valve used in conjunction with a liquid ring pump in a vacuum water priming equipment. Background Technology

[0002] The term "vacuum breaking" in the title of this utility model, also known as "vacuum opening," "vacuum destruction," or "vacuum breaking," refers to the use of appropriate technical means to reduce the vacuum level inside a vacuum water priming device—typically a pumping system composed of a liquid ring vacuum pump (hereinafter referred to as: liquid ring pump) and its supporting equipment—after completing a certain process, such as injecting water meeting process requirements into a centrifugal water pump (hereinafter referred to as: centrifugal pump) and its pipeline before startup. This prevents damage to the vacuum water priming device due to water ingress. In short, "vacuum breaking" is a technical measure to protect the vacuum water priming device by eliminating the vacuum effect.

[0003] Regarding the specific technical means of "vacuum breaking," the most direct technical means at present is to configure a vacuum breaking stop valve (also known as a vacuum breaker valve or similar name) in the vacuum water priming equipment. For example, the invention patent application with publication number CN103883772 A discloses a vacuum breaker valve, including a valve body 1, with an air inlet at the upper end and an air outlet at the lower end. A valve seat 5 and a valve disc 2 are installed inside the valve body 1. The valve disc 2 is rotatably connected to a valve shaft 6 set on the valve body 1 through a valve disc arm 3. The valve disc arm 3 is fixedly connected to a counterweight 7 through a connecting arm 8. Specifically, one end of the valve disc arm 3 is fixedly connected to the valve disc 2 through a first screw 9, and the other end of the valve disc arm 3 is provided with a connecting ring 10. The connecting ring 10 is sleeved on the circumference of the valve shaft 6 and is rotatably connected to the valve shaft 6. The outer circle of the connecting ring 10 is fixedly connected to the connecting arm 8. The working principle of this invention is as follows: Under normal circumstances, the gravitational torque of the counterweight 7 and the internal pressure of the valve body 1 are greater than the gravitational force of the valve disc 2, keeping the valve disc 2 closed on the valve seat 5. When the system stops pumping or an emergency occurs such as a power outage, the water in the pipeline flows under the influence of its own kinetic energy, potential energy, and pipeline elevation. At the pipeline inflection point, uneven flow velocity creates negative pressure in the pipeline. When the pressure inside the pipeline or valve body 1 drops to a certain point, the atmospheric pressure on the valve disc 2 breaks the torque balance on the valve shaft 6, causing the valve disc 2 to detach from the valve seat 5. The valve seat 5 opens, and atmospheric air enters the valve body 1 to compensate for the vacuum, ensuring that the system is protected from damage by vacuum pressure. When a flow interruption occurs within the valve body 1, the air entering the valve body 1 acts as a buffer, reducing the impact force of the water hammer and mitigating potential water hammer in the system. When the internal pressure of the valve body 1 returns to normal, the valve disc 2 automatically closes again under the gravity of the counterweight 7.

[0004] For example, the invention patent with authorization announcement number CN105402116B discloses an air-extraction type water-stopping device, including a water tank 4. The lower part of the water tank 4 is provided with a water inlet, and a water pipe 1 connected to a water pump is connected to the water inlet. A ball valve 2 is installed on the water pipe 1. The upper part of the water tank 4 is provided with an air extraction port, and an air extraction pipe 15 connected to a vacuum pump is connected to the air extraction port. The upper part of the water tank 4 is also provided with a mounting hole corresponding to the air extraction port. One end of a control rod 22 for opening / closing the air extraction port extends into the water tank 4 through the mounting hole. The water tank 4 is equipped with a limiting device for coordinating the operation of the control rod according to the water level in the water tank 4. The other end of the control rod 22 is equipped with a handle 28. Near the inner wall of the water tank 4 at the mounting hole, there is a device that matches the control rod. The guide post sleeve 24 is assembled with a control rod 22, on which a compression spring 23 is fitted to abut against the guide post sleeve 24. A sealing ball 20 for sealing the air extraction port is provided at the end of the control rod 22. The limiting device includes a guide sleeve rod 14, a support rod 9, a lever 6, and a hollow ball 5 that can float on water, mounted on the lower end of the lever 6. The upper end of the lever 6 is movably hinged to a lower wedge block 21 mounted on the guide sleeve rod. A return spring 11 is provided at the hinge point between the lever 6 and the lower wedge block 21. An upper wedge block that cooperates with the lower wedge block 21 is provided on the control rod 22. The middle part of the lever 6 is movably hinged to the support rod 9. The control rod 22 is provided with a control button that cooperates with the switch toggle of the vacuum pump power switch to turn the vacuum pump on / off. The working principle of the technical solution disclosed in invention patent CN105402116B is basically the same as that of the technical solution disclosed in invention patent application CN 103883772A, and will not be repeated here.

[0005] In general, the technical solutions disclosed in invention patents or patent applications CN103883772 A and CN105402116B can eliminate the damage to equipment caused by the vacuum effect, but they also have some technical defects. Specifically, the main technical defects of the vacuum breaker valve disclosed in invention patent application CN 103883772 A are as follows:

[0006] First, in this invention, the counterweight 7 is located outside the valve body 1, and is connected to the valve disc arm 3 located inside the valve body 1 via a connecting arm 8. The valve disc arm 3 is then connected to the valve disc 2 inside the valve body 1, which serves a sealing function. This structural design increases the difficulty of sealing the valve body 1. Specifically, to ensure that the counterweight 7 moves up and down to open or close the valve disc 2, a guide groove needs to be provided on the side of the valve body 1 facing the counterweight 7. Its function is to allow the connecting arm 8 to pass through the guide groove and connect the counterweight 7 outside the valve body 1 to the valve disc arm 3 inside the valve body 1, and the connecting arm 8 can move up and down within the guide groove. When the connecting arm 8 is stationary relative to the guide groove, the guide groove is easy to seal. However, when the connecting arm 8 moves up and down relative to the guide groove, sealing the guide groove becomes very difficult. Although there are corresponding sealing methods, they make the system structure very complex, increasing the manufacturing and maintenance costs of the equipment.

[0007] Secondly, since the counterweight 7 is externally mounted, space needs to be reserved for it when designing the vacuum water priming equipment to ensure its vertical movement. For simple vacuum water priming equipment, reserving space for the counterweight 7 is not particularly difficult. However, for complex vacuum water priming equipment, especially when used in conjunction with a large centrifugal pump, reserving space for the counterweight 7 is more challenging. Even if space can be reserved for the counterweight 7, it will complicate the piping layout within the system.

[0008] The main technical defects of the air-extraction water-stopping device disclosed in invention patent CN105402116B are as follows:

[0009] First, when the water level inside the device reaches a certain level, the hollow ball (float) in the device drives the connecting rod, which in turn drives a trigger-like module to shut off the air inlet and power supply of the vacuum pump. This structural design makes it difficult to modify the device for remote control or the cost of doing so is too high.

[0010] Secondly, the process of restarting the device is quite complicated, requiring manual pulling of the handle to reset the system.

[0011] Third, the use of this device will cause some damage to the liquid ring pump, affecting its service life. This is because when the vacuum pump is shut down, its inlet is also closed. Since the vacuum pump is still running, the inlet is abruptly closed before it has completely stopped, which damages the liquid ring pump and shortens the system's lifespan.

[0012] Besides the technical solutions disclosed in the aforementioned invention patents or patent applications, existing technologies also provide other vacuum-breaking solutions. For example, the vacuum effect can be eliminated by installing components such as pressure transmitters and electrically controlled valves at the front end of the liquid ring pump; another example is eliminating the vacuum effect by installing components such as a pre-positioned water tank, a level sensor, and an electrically controlled valve at the front end of the liquid ring pump. However, these technical solutions also have varying degrees of technical defects.

[0013] Taking a solution that uses pressure transmitters and electrically controlled valves to eliminate the vacuum effect as an example, this solution requires shutting down the liquid ring pump simultaneously with closing the electrically controlled valve; otherwise, severe cavitation or even damage to the liquid ring pump may occur. In particular, during actual use, there is a possibility that the electrically controlled valve may not operate in a timely manner, or that the sensor may be unresponsive or even malfunction, resulting in the inability to stop water flow promptly during priming. This could lead to water or other liquids entering the liquid ring pump and damaging it.

[0014] Taking the solution that eliminates the vacuum effect using components such as a pre-storage tank, level sensor, and electrically controlled valve as an example, this solution can provide some buffering and protection for the liquid ring pump by adding a pre-storage tank. However, this solution requires shutting down the liquid ring pump at the same time as closing the electrically controlled valve. In particular, if sufficient air cannot be quickly introduced to raise the pressure in the pre-storage tank back to atmospheric pressure before closing the valve, water in the pre-storage tank may not be able to drain out and may be sucked into the liquid ring pump, thereby damaging it. In addition, this solution also has drawbacks such as the large space occupied by the pre-storage tank, a more complex control system, more potential failure points, and significantly increased manufacturing and maintenance costs. Summary of the Invention

[0015] The purpose of this utility model is to overcome the technical defects of the prior art, especially the technical defects of the vacuum breaker valve, which has the problem of difficult valve body sealing and is not suitable for complex vacuum water priming equipment.

[0016] To achieve the above objectives, the present invention adopts the following technical solution:

[0017] A vacuum-breaking stop valve includes a valve body and a partition plate. The partition plate divides the internal space of the valve body into an outlet channel and an inlet channel. The outlet of the outlet channel is located on one side of the bottom of the valve body, and the inlet of the inlet channel is located on the other side of the top of the valve body. The partition plate has a connecting channel opening that connects the inlet channel and the outlet channel. A return water hole is provided on the side of the partition plate near the bottom of the valve body. A float is provided below the connecting channel opening, and a connecting rod passing through the connecting channel opening is provided above the float. A vacuum-breaking chamber is provided at the top of the valve body. A vent hole is provided on the outer shell of the vacuum-breaking chamber. A connecting rod inlet and a sealing module that seals the connecting rod inlet are provided at the bottom of the vacuum-breaking chamber. The upper end of the connecting rod passes through the connecting rod inlet and is fixedly connected to the sealing module. When the float floats upward, the connecting rod drives the sealing module to move upward, so that the outlet channel is connected to the vacuum-breaking chamber and the outside atmosphere. When the float falls, the connecting rod drives the sealing module to move downward, so that the connecting rod inlet is closed.

[0018] Based on the above technical solution, the present invention may be supplemented with the following technical means to better or more specifically solve the technical problem to be solved by the present invention:

[0019] The float is shaped like a sphere, cylinder, ellipsoid, or cuboid, with a specific gravity less than that of water. The shape and area of ​​its cross-section match the shape and area of ​​the connecting channel opening. It is positioned directly below the connecting channel opening and can close the connecting channel opening when it floats.

[0020] Furthermore, the valve body is a cylindrical valve body, and the vacuum breaking chamber is located at the top center of the valve body.

[0021] Furthermore, the valve body is a square valve body, and the vacuum breaking chamber is located at one of the top corners of the valve body.

[0022] Furthermore, the float, connecting rod, and sealing module are sequentially connected to form an integral structure.

[0023] Furthermore, the float is disconnected from the connecting rod, and the length of the connecting rod is shortened by half.

[0024] Furthermore, a retainer is provided, which is connected and fixed to the valve body and located below the connection channel opening. The retainer is in the shape of a round tube or a square tube, and the float is disposed in the retainer.

[0025] Furthermore, a flow port is provided at the bottom of the cage.

[0026] Furthermore, the area of ​​the overflow port is larger than the inlet area of ​​the air intake channel.

[0027] Compared with the technical solutions disclosed in invention patents or patent applications CN105402116B and CN 103883772 A, as well as other existing technical solutions for eliminating vacuum effects, this utility model has the following beneficial technical effects:

[0028] First, it has a simple and reliable structure, low manufacturing cost, and convenient installation, making it suitable for situations where the structure of vacuum water priming equipment is complex.

[0029] Secondly, since it is not necessary to immediately shut off the air inlet valve and the liquid ring pump power supply after successful water intake, this invention can automatically and quickly break the vacuum and stop the water flow, thus greatly reducing the use of sensors and control systems.

[0030] Third, it reduces cavitation and water hammer phenomena in liquid ring pumps. When necessary, this invention will first break the vacuum to prevent the vacuum level inside the liquid ring pump from rising significantly, thus reducing the damage to the liquid ring pump caused by cavitation. During the water shut-off process, due to the breaking of the vacuum and the reduction of the vacuum level in the pipeline, the flow velocity of the liquid in the pipeline is reduced, which reduces the kinetic energy of the liquid and thus reduces the damage to the pipeline caused by the water hammer effect.

[0031] Fourth, it is easy to convert to remote control. Only a vacuum gauge needs to be installed in the device. By observing the change in its vacuum level, it can be determined whether the system has successfully started water intake. This utility model can realize the remote control of the liquid ring pump and vacuum pump switch, thereby simultaneously realizing vacuum breaking and water stopping.

[0032] In summary, this utility model has a simple structure and is easy to operate. During use, it does not require immediate shutdown of the air inlet valve and the liquid ring pump power supply, which can effectively reduce the possibility of water or other liquids entering the liquid ring pump, thereby increasing the reliability and service life of the vacuum priming equipment. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of a vertical cross-section of Embodiment 1 of this utility model;

[0034] Figure 2 This is a schematic diagram of a vertical cross-section of Embodiment 1 of this utility model;

[0035] In the picture:

[0036] 1 – Exhaust channel; 2 – Intake channel;

[0037] 3 – Connection port; 4 – Vent hole;

[0038] 5 – Vacuum breaking chamber; 6 – Water return hole;

[0039] 7 – Float; 8 – Connecting rod;

[0040] 9 – Sealing module; 10 – Cage;

[0041] 11—Flow port; 12—Valve body;

[0042] 13 - Divider. Detailed Implementation

[0043] To facilitate a full understanding of this technical solution by those skilled in the art, two embodiments of this utility model are described below in conjunction with the accompanying drawings.

[0044] Example 1

[0045] like Figure 1 As shown, a vacuum-breaking stop valve includes a valve body 12 (the valve body refers to the outer shell of the vacuum-breaking stop valve) and a partition plate 13; the partition plate 13 divides the internal space of the valve body 12 into an air outlet channel 1 and an air inlet channel 2, and the outlet of the air outlet channel 1 is located on one side of the bottom of the valve body 12 (corresponding to...). Figure 1 The lower left position of the intake passage 2 is located on the other side of the top of the valve body 12 (corresponding to the lower left position). Figure 1(The upper right position in the middle); the partition plate 13 is provided with a connecting channel port 3 that connects the air inlet channel 2 and the air outlet channel 1. A water return hole 6 is provided on the side of the partition plate 13 near the bottom of the valve body 12; a float 7 is provided below the connecting channel port 3, and a connecting rod 8 passing through the connecting channel port 3 is provided above the float 7; a vacuum breaking chamber 5 is provided at the top of the valve body 12. A vent hole 4 is provided on the outer shell of the vacuum breaking chamber 5. A connecting rod inlet and a sealing module 9 that seals the connecting rod inlet are provided at the bottom of the vacuum breaking chamber 5 (the connecting rod inlet is also the channel between the air outlet channel 1 and the vacuum breaking chamber 5); the upper end of the connecting rod 8 passes through the connecting rod inlet and is fixedly connected to the sealing module 9; when the float 7 floats upward, the connecting rod 8 drives the sealing module 9 to move upward, so that the air outlet channel 1 is connected to the vacuum breaking chamber 5 and the outside atmosphere; when the float 7 falls, the connecting rod 8 drives the sealing module 9 to move downward, so that the connecting rod inlet is closed (that is, the channel between the air outlet channel 1 and the vacuum breaking chamber 5 is closed).

[0046] It should also be noted that in this embodiment, the float 7 is spherical. However, depending on actual needs, the float 7 can also be designed as a cylinder, ellipse, cuboid, or other shapes. The specific gravity of the float 7 is less than that of water, and the shape and area of ​​its cross-section match the shape and area of ​​the connecting channel opening 3 (the former is slightly larger than the latter). It is positioned directly below the connecting channel opening 3, and when it floats, it can close the connecting channel opening 3.

[0047] Furthermore, the overall shape of the valve body 12 can be cylindrical (circular cross-section) or square (square or rectangular cross-section). When the valve body 12 is cylindrical, the vacuum breaking chamber 5 is located at the top center of the valve body 12. When the valve body 12 is square, the vacuum breaking chamber 5 is located at one of the top corners of the valve body 12.

[0048] Example 2

[0049] The structure of Example 2 is basically the same as that of Example 1. The difference between the two is as follows: Figure 1 As shown, in Embodiment 1, the float 7, connecting rod 8, and sealing module 9 are sequentially connected to form an integral structure—which can be collectively referred to as the float connecting rod module; as Figure 2 As shown, in Embodiment 2, the float 7 and the connecting rod 8 are disconnected. That is, when the float 7 is not floating, the float 7 and the connecting rod 8 are not in contact, and the length of the connecting rod 8 is shortened by half (the specific dimensions of the connecting rod 8 and other components can be adjusted according to actual needs). In other words, in Embodiment 2, the float connecting rod module is divided into two parts: one part is the connecting rod 8 and its fixedly connected sealing module 9, and the other part is the float 7.

[0050] In addition to the differences mentioned above, the vacuum-breaking stop valve corresponding to Embodiment 2 is also provided with a retainer 10. The retainer 10 is connected and fixed to the valve body 12 and is located below the connection channel opening 3. The retainer 10 is in the shape of a round tube or a square tube (for example, a square tube made of four iron plates). The float 7 is disposed in the retainer 10, and the bottom of the retainer 10 is provided with a flow port 11.

[0051] The cage 10 restricts the left-right and back-right movement of the float 7, ensuring that the float 7 can only rise or fall, thus preventing the float 7 from deviating during its ascent or descent. The outlet 11 allows water or other liquids to enter or exit the cage 10, causing the float 7 to rise with the entry of water or other liquids and fall with the exit of water or other liquids. To facilitate the entry or exit of water or other liquids from the cage 10, in this embodiment, the area of ​​the outlet 11 (also called the flow area) is larger than the area of ​​the inlet of the air intake channel 2 (also called the air intake port).

[0052] Example 2 employs a technique in which the float 7 is disconnected from the connecting rod 8 and the length of the connecting rod 8 is shortened by half (compared to the connecting rod 8 in Example 1). The purpose is to shorten the stroke of the connecting rod 8, thereby making the time interval between breaking the vacuum and stopping the water flow shorter.

[0053] Unlike Embodiment 2, in Embodiment 1, the float 7, connecting rod 8, and sealing module 9 are sequentially connected to form an integral structure. The sealing module 9, with a certain thickness, is tightly engaged in the vacuum-breaking chamber 5, allowing it to move only up and down within the chamber and preventing it from swinging back and forth or left and right. Therefore, in Embodiment 1, there is no need to separately install a retainer 10.

[0054] The structural features of two embodiments of this utility model have been described above with reference to the accompanying drawings. The working principle of this utility model will be further introduced below, taking a water priming system composed of a centrifugal pump and a vacuum water priming device as an example.

[0055] In use, the air outlet 1 of the vacuum-breaking stop valve is connected to the air inlet of the liquid ring pump, and the air inlet 2 is connected to the centrifugal pump. When the vacuum priming equipment needs to be operated, the liquid ring pump is started to remove the air from the centrifugal pump, creating a certain degree of vacuum. The pumped liquid enters the centrifugal pump along the pipeline under atmospheric pressure. During this stage, the float 7 of the vacuum-breaking stop valve and its matching connecting rod 8 do not move, the system is relatively closed, and it is not connected to the outside atmosphere.

[0056] When the sound of air being drawn in is observed through the vent channel 1 of the vacuum-breaking stop valve, it indicates that the level of the pumped liquid has reached a certain height, and the centrifugal pump can be started. During this stage, the float 7 of the vacuum-breaking priming valve rises with the liquid level; after reaching a certain height, the float 7 comes into close contact with the connecting channel 3 above it, sealing the connecting channel 3 and thus achieving a water-stopping effect. Simultaneously, the connecting rod 8 above the float 7 drives the sealing module 9 upwards, connecting the liquid ring pump to the vacuum-breaking chamber 5 and the external atmosphere, thereby achieving a vacuum-breaking effect. It should also be noted that during vacuum breaking, the vent channel 2 will also emit a loud whistling sound, indicating that the liquid has entered the vacuum-breaking stop valve and reached a certain height. At this point, the vacuum priming equipment can be shut off. After the equipment is shut off, the water accumulated in the vacuum-breaking stop valve will flow into the liquid ring pump through the return water hole 6.

[0057] As can be seen from the above description of the technical content, after the water priming stage is completed, compared with the existing water priming systems including centrifugal pumps and vacuum water priming equipment, the water priming system of this utility model does not have strict requirements on the timing of closing the air inlet valve and the liquid ring pump switch. It can eliminate complex sensors and control devices, and can automatically and quickly break the vacuum and stop the water, effectively preventing water or other liquids from damaging the liquid ring pump and its pipelines, thereby increasing the reliability and service life of the vacuum water priming equipment.

Claims

1. A vacuum-breaking stop valve, comprising a valve body and a partition plate; the partition plate divides the internal space of the valve body into an outlet channel and an inlet channel, the outlet of the outlet channel being located on one side of the bottom of the valve body, and the inlet of the inlet channel being located on the other side of the top of the valve body; the partition plate is provided with a connecting channel opening that connects the inlet channel and the outlet channel; characterized in that: A return water hole is provided on the side of the partition plate near the bottom of the valve body; a float is provided below the connecting channel opening, and a connecting rod passing through the connecting channel opening is provided above the float; a vacuum breaking chamber is provided at the top of the valve body, and a vent is provided on the outer shell of the vacuum breaking chamber; a connecting rod inlet and a sealing module that seals the connecting rod inlet are provided at the bottom of the vacuum breaking chamber; the upper end of the connecting rod passes through the connecting rod inlet and is fixedly connected to the sealing module; when the float floats upward, the connecting rod drives the sealing module to move upward, so that the vent channel is connected to the vacuum breaking chamber and the outside atmosphere; when the float falls, the connecting rod drives the sealing module to move downward, so that the connecting rod inlet is closed.

2. The vacuum-breaking stop valve as described in claim 1, characterized in that: The float is shaped like a sphere, cylinder, ellipsoid, or cuboid, with a specific gravity less than that of water. The shape and area of ​​its cross-section match the shape and area of ​​the connecting channel opening. It is positioned directly below the connecting channel opening and can close the connecting channel opening when it floats.

3. The vacuum-breaking stop valve as described in claim 1, characterized in that: The valve body is a cylindrical valve body, and the vacuum breaking chamber is located at the top center of the valve body.

4. The vacuum-breaking stop valve as described in claim 1, characterized in that: The valve body is a square valve body, and the vacuum breaking chamber is located at the top corner of the valve body.

5. The vacuum-breaking stop valve as described in claim 1, characterized in that: The float, connecting rod, and sealing module are connected in sequence to form an integral structure.

6. The vacuum-breaking stop valve as described in claim 5, characterized in that: The float is disconnected from the connecting rod, and the length of the connecting rod is reduced by half.

7. The vacuum-breaking stop valve as described in claim 6, characterized in that: It is also provided with a retainer, which is connected and fixed to the valve body and is located below the connection channel opening. The retainer is in the shape of a round tube or a square tube, and the float is disposed in the retainer.

8. The vacuum-breaking stop valve as described in claim 7, characterized in that: A flow port is provided at the bottom of the cage.

9. The vacuum-breaking stop valve as described in claim 8, characterized in that: The area of ​​the overflow port is larger than the inlet area of ​​the air intake channel.

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