Negative pressure pile-up valve with switching function

Abstract

The utility model discloses a negative pressure pile-up valve with a switch function, which belongs to the technical field of valves, and comprises a pile-up valve body, a switch valve core and a pressure limiting valve core are arranged on the pile-up valve body, the switch valve core is used for controlling the connection and disconnection of a fluid channel, and the pressure limiting valve core is used for limiting the pressure of the fluid channel. The pressure limiting valve element is used for controlling connection and disconnection between the fluid channel and the external atmosphere according to the pressure in the fluid channel. The negative pressure pile-up valve with the switching function integrates the functions of a switching valve and a pressure limiting valve, is compact in structure, and reduces the use of independent parts. The switching valve can conduct or cut off a channel communicated with the pressure air source, and the channel can be cut off by closing the switching valve after the pressure air source is closed. The function of the pressure limiting valve can limit the pressure in the container, so that the system can stably output negative pressure within a set range when different pressure air sources are adopted, and equipment damage and safety accidents caused by different air source pressures are avoided.

Description

Technical Field

[0001] This utility model relates to a negative pressure integrated valve with a switching function, belonging to the field of valve technology. Background Technology

[0002] Negative pressure systems have wide applications in laboratories, chemical production, and medical fields. For example, negative pressure filtration equipment in laboratories requires setting a pressure relief valve threshold during operation. The system maintains negative pressure once it reaches -0.08 MPa, and releases excess pressure when this value is exceeded to maintain a vacuum environment. In chemical plants, negative pressure switches monitor pressure changes within tanks during loading and unloading. When the pressure exceeds a safe range (e.g., +0.3 MPa or -0.02 MPa), loading and unloading are automatically suspended and an alarm is triggered, preventing tank deformation due to pressure imbalance. Furthermore, pressure-limiting valves are used during transportation to balance the pressure of the medium caused by temperature changes, preventing overpressure explosions. Medical institutions also use negative pressure limiting valves during medical diagnosis, treatment, and research. For example, in the dialysis fluid circuit, pressure limiting valves are needed to control the transmembrane pressure within the range of 100-300 mmHg to ensure toxin removal efficiency while preventing red blood cell rupture. Furthermore, negative pressure switches are needed to monitor the pressure in the tubing after the blood pump. When coagulation or tubing kinking causes a sudden increase in pressure (e.g., >300 mmHg), an alarm is immediately triggered and the blood pump is stopped to prevent the risk of thromboembolism.

[0003] Negative pressure switches and pressure limiting valves are essential components for maintaining stable operation of the aforementioned negative pressure systems. This utility model aims to provide a new type of valve to solve the defects of traditional negative pressure systems, such as unstable pressure and complex valve structure. Utility Model Content

[0004] In order to solve the problems existing in the prior art, this utility model provides a negative pressure integrated valve with a switching function, which enables the system to stably output negative pressure within a set range when using different pressure air sources, thereby avoiding equipment damage and safety accidents caused by different air source pressures.

[0005] This utility model achieves the above objectives by adopting the following technical solutions:

[0006] A negative pressure integrated valve with a switching function includes an integrated valve body, on which a fluid channel is provided, and the two ports of the fluid channel respectively form a first air inlet and a second air inlet. The integrated valve body is provided with a switching valve core and a pressure limiting valve core.

[0007] The integrated valve body has a first valve chamber, which is connected to a fluid channel. One end of the switch valve core is inserted into the first valve chamber, and the switch valve core is used to control the opening and closing of the fluid channel.

[0008] A second valve chamber is provided on the pressure limiting valve core or the integrated valve body. The second valve chamber has an external port that communicates with the external atmosphere and an internal port that communicates directly or indirectly with the fluid channel. The pressure limiting valve core is inserted into the second valve chamber. The pressure limiting valve core is used to control the connection and disconnection between the fluid channel and the external atmosphere according to the pressure in the fluid channel.

[0009] Furthermore, a switching flow channel is provided through the end of the switching valve core inserted into the first valve chamber. The switching valve core is rotatable relative to the first valve chamber. The rotation axis of the switching valve core is perpendicular to the axis of the fluid channel and the switching flow channel. During the rotation of the switching valve core, the switching flow channel is either connected to or disconnected from the fluid channel.

[0010] Furthermore, the pressure limiting valve core includes a pressure limiting valve core body, a ball, and a spring.

[0011] In the first embodiment, the second valve chamber is formed on the switch valve core, the outer port of the second valve chamber is connected to the external atmosphere, and the inner port of the second valve chamber is connected to the switch flow channel;

[0012] A pressure-limiting flow channel is formed through the pressure-limiting valve core body. The pressure-limiting flow channel has an outer port that communicates with the external atmosphere and an inner port that communicates with the second valve chamber. The inner diameter of the outer port of the pressure-limiting flow channel is smaller than the inner diameter of the middle part of the pressure-limiting flow channel.

[0013] The ball is positioned inside the pressure limiting channel and close to the outer port of the pressure limiting channel. The diameter of the ball is larger than the inner diameter of the outer port of the pressure limiting channel. The two ends of the spring abut against the cavity wall around the ball and the inner port of the second valve cavity, respectively. Under the action of the spring force, the ball abuts against the outer port of the pressure limiting channel.

[0014] In the second embodiment, the second valve chamber is formed on the integrated valve body. However, the second valve chamber and the first valve chamber can be arranged either offset from each other or directly opposite each other along the axial direction of the fluid channel.

[0015] Meanwhile, in the second embodiment, the pressure relief valve core also has two different structures.

[0016] In the first pressure-limiting valve core structure, when the second valve chamber and the first valve chamber are offset from each other along the axial direction of the fluid channel, a pressure-limiting flow channel is formed through the pressure-limiting valve core body. The pressure-limiting flow channel has an outer port that communicates with the external atmosphere and an inner port that communicates with the second valve chamber. The inner diameter of the outer port of the pressure-limiting flow channel is smaller than the inner diameter of the middle part of the pressure-limiting flow channel.

[0017] The ball is positioned inside the pressure limiting channel and close to the outer port of the pressure limiting channel. The diameter of the ball is larger than the inner diameter of the outer port of the pressure limiting channel. The two ends of the spring abut against the cavity wall around the ball and the inner port of the second valve cavity, respectively. Under the action of the spring force, the ball abuts against the outer port of the pressure limiting channel.

[0018] In the first pressure-limiting valve core structure, when the second valve chamber and the first valve chamber are directly opposite each other along the axial direction of the fluid channel, the second valve chamber and the first valve chamber are directly connected. A flow channel is provided on the end face of the switch valve core facing the second valve chamber, and the two ports of the flow channel are respectively connected to the switch flow channel and the first valve chamber.

[0019] In the second type of pressure-limiting valve core structure, the second valve chamber and the first valve chamber are offset from each other along the axial direction of the fluid channel. The second valve chamber passes through the integrated valve body and has a first port and a second port that communicate with the external atmosphere. The inner diameter of the second port of the second valve chamber is smaller than the inner diameter of the middle part of the second valve chamber.

[0020] The pressure-limiting valve core body is inserted at the first port of the second valve cavity, and the ball is located at the second port of the second valve cavity. The diameter of the ball is larger than the inner diameter of the second port of the second valve cavity. The two ends of the spring abut against the ball and the pressure-limiting valve core body respectively. Under the action of the spring force, the ball abuts against the second port of the second valve cavity.

[0021] Furthermore, sealing rings are provided on the contact surface between the switching valve core and the first valve chamber, as well as on the contact surface between the pressure limiting valve core body and the second valve chamber.

[0022] Preferably, the pressure relief valve core body is threadedly connected to the second valve chamber.

[0023] The beneficial effects of this utility model include, but are not limited to:

[0024] This utility model provides a negative pressure integrated valve with a switching function, which integrates the functions of a switching valve and a pressure limiting valve. Its compact structure reduces the use of independent components. The switching valve function can open or close the channel connected to the pressurized gas source; after the pressurized gas source is shut off, the channel can be cut off by closing the switching valve. The pressure limiting valve function can limit the pressure inside the container, ensuring that the system can stably output a negative pressure within a set range when using different pressurized gas sources, avoiding equipment damage and safety accidents caused by differences in gas source pressure. Attached Figure Description

[0025] The accompanying drawings, which are included to provide a further understanding of the present invention and constitute a part of this invention, illustrate exemplary embodiments of the present invention and, together with the description thereof, serve to explain the present invention and do not constitute an undue limitation thereof. In the drawings:

[0026] Figure 1A schematic diagram of the structure of the negative pressure integrated valve with switching function provided in Example 1;

[0027] Figure 2 This is a schematic diagram of the switching flow channel on the switching valve core.

[0028] Figure 3 This is a schematic diagram of the structure of the negative pressure integrated valve with switching function provided in Example 2;

[0029] Figure 4 This is a schematic diagram of the first valve chamber and the second valve chamber in Example 2;

[0030] Figure 5 This is a schematic diagram of the structure of the negative pressure integrated valve with switching function provided in Example 3;

[0031] Figure 6 This is a schematic diagram of the structure of the negative pressure integrated valve with switching function provided in Example 4;

[0032] In the diagram, 100 is the integrated valve body; 110 is the fluid passage; 111 is the first air inlet; and 112 is the second air inlet.

[0033] 200, Switch valve core; 210, First valve chamber; 220, Switch flow channel; 230, Conducting flow channel;

[0034] 300, Pressure limiting valve core; 310, Second valve chamber; 320, Pressure limiting valve core body; 330, Ball; 331, Rod; 340, Spring; 350, Pressure limiting flow channel;

[0035] 400. Sealing ring. Detailed Implementation

[0036] To clearly illustrate the technical features of this solution, the present invention will be described in detail below through specific embodiments and in conjunction with the accompanying drawings.

[0037] It should be noted that many specific details are set forth in the following description to provide a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0038] like Figures 1-6 As shown, the negative pressure integrated valve with switching function provided by this utility model includes an integrated valve body 100. A fluid channel 110 is provided through the integrated valve body 100. The two ports of the fluid channel 110 respectively form a first air inlet 111 and a second air inlet 112. A switching valve core 200 and a pressure limiting valve core are provided on the integrated valve body 100.

[0039] The function of the switching valve core 200 is to directly control the opening and closing of the fluid channel 110, while the pressure limiting valve core controls the opening and closing of the fluid channel 110 with the external atmosphere according to the pressure in the fluid channel 110.

[0040] The negative pressure integrated valve with switching function provided by this utility model, when applied to a negative pressure filtration container, connects the first air inlet 111 to the filtration container and the second air inlet 112 to a pressure gas source (vacuum pump). The pressure gas source draws gas from the filtration container through the fluid channel 110, bringing the filtration container to the required negative pressure. During the operation of the pressure gas source, the switching valve core 200 is in the state of opening the fluid channel 110, allowing gas to be drawn out of the filtration container. Simultaneously, the pressure limiting valve core is in the working state. When the pressure difference between the filtration container and the external atmosphere exceeds a set value, the pressure limiting valve core opens the fluid channel 110 to the external atmosphere, allowing outside air to compensate and enter the container, preventing excessive negative pressure and deformation due to pressure imbalance. When the pressure difference between the filtration container and the external atmosphere is within the set range, the pressure limiting valve core cuts off the fluid channel 110 from the external atmosphere, allowing gas to continue to be drawn out of the filtration container or maintaining it at the specified negative pressure.

[0041] After the filtration operation is completed, turn off the pressure gas source and close the fluid channel 110 through the switch valve core 200 to prevent the filtrate from being sucked back into the vacuum pump and damaging the equipment.

[0042] This invention overcomes the shortcomings of traditional liquid phase filtration systems, such as unstable negative pressure, easy overpressure, and complex structure.

[0043] In actual manufacturing, the pressure relief valve core can be integrated onto the switching valve core 200, or both the pressure relief valve core and the switching valve core 200 can be directly mounted onto the integrated valve body 100.

[0044] The integrated valve requires a first valve chamber 210 and a second valve chamber 310 for mounting the switching valve core 200 and the pressure-limiting valve core. When the pressure-limiting valve core is integrated into the switching valve core 200, the first valve chamber 210 is directly formed on the integrated valve body 100, and the second valve chamber 310 is formed on the pressure-limiting valve core. When both the pressure-limiting valve core and the switching valve core 200 are directly mounted on the integrated valve body 100, both the second valve chamber 310 and the first valve chamber 210 are directly formed on the integrated valve body 100.

[0045] The first valve chamber 210 is configured on the integrated valve body 100 as follows: the first valve chamber 210 crosses the fluid channel 110, and the two are connected to each other at the intersection. One end of the switch valve core 200 is inserted into the first valve chamber 210. The switch valve core 200 is used to control the opening and closing of the fluid channel 110.

[0046] like Figure 2As shown, a switching flow channel 220 is provided through the end of the switching valve core 200 inserted into the first valve chamber 210, allowing the switching valve core 200 to rotate relative to the first valve chamber 210. The rotation axis of the switching valve core 200 is perpendicular to the axes of the fluid channel 110 and the switching flow channel 220. During rotation, the switching valve core 200 keeps the switching flow channel 220 either connected to or disconnected from the fluid channel 110. The outer end of the switching valve core 200, serving as the control end, can be designed as a straight-line structure for easy gripping and rotation.

[0047] The second valve chamber 310 has an external port that communicates with the external atmosphere and an internal port that communicates directly or indirectly with the fluid channel 110. The pressure limiting valve core is inserted into the second valve chamber 310 and is secured by the reverse teeth.

[0048] Furthermore, the pressure-limiting valve core includes a pressure-limiting valve core body 320, a ball 330, and a spring 340. The pressure-limiting valve core body 320 is inserted into the second valve chamber 310, and the contact surface between the pressure-limiting valve core body 320 and the second valve chamber 310 is sealed. When the pressure inside the filtration container is within the set range, the ball 330 can cut off the passage between the external atmosphere and the fluid channel 110 under the elastic force of the spring 340. When the negative pressure inside the filtration container exceeds the set value, the atmospheric pressure of the external atmosphere acts on the ball 330, causing the ball 330 to move, releasing the blockage of the second valve chamber 310. Atmosphere then enters the fluid channel 110 through the second valve chamber 310 to compensate, preventing excessive negative pressure inside the filtration container.

[0049] This invention uses a sensing triggering component composed of a ball 330 and a spring 340 to sense changes in the negative pressure of the system in real time, and automatically opens and closes the pressure compensation port according to the negative pressure setting value to accurately maintain the stability of the negative pressure of the system.

[0050] The integrated valve uses corrosion-resistant materials to adapt to a variety of liquid samples, improving its applicability and service life.

[0051] The following will describe the configuration of the switching valve core 200 and the pressure limiting valve core through specific embodiments.

[0052] Example 1:

[0053] like Figure 1 As shown in the figure, in this embodiment, the pressure relief valve core is integrated on the switching valve core 200.

[0054] Specifically, the second valve chamber 310 is located on the switch valve core 200. The outer port of the second valve chamber 310 is connected to the external atmosphere, and the inner port of the second valve chamber 310 is connected to the switch flow channel 220.

[0055] A pressure limiting flow channel 350 is formed through the pressure limiting valve core body 320. The pressure limiting flow channel 350 has an outer port that communicates with the external atmosphere and an inner port that communicates with the second valve chamber 310. The axis of the pressure limiting flow channel 350 is perpendicular to the fluid channel 110. The inner diameter of the outer port of the pressure limiting flow channel 350 is smaller than the inner diameter of the middle part of the pressure limiting flow channel 350.

[0056] The sphere 330 is disposed within the pressure-limiting flow channel 350 and near its outer port. The diameter of the sphere 330 is larger than the inner diameter of the outer port of the pressure-limiting flow channel 350. The two ends of the spring 340 abut against the sphere 330 and the cavity wall surrounding the inner port of the second valve chamber 310, respectively. Under the elastic force of the spring 340, the sphere 330 abuts against the outer port of the pressure-limiting flow channel 350. Thus, the pressure-limiting flow channel 350 is blocked by the sphere 330.

[0057] To improve the stability of the extension and retraction of the spring 340, a rod 331 is usually fixed on the ball 330. The diameter of the ball 330 is larger than the diameter of the rod 331, and the spring 340 is fitted onto the rod 331. The rod 331 only serves to stabilize the extension and retraction of the spring 340, and its diameter cannot be too large so as not to obstruct the valve cavity, fluid passage 110, or other parts.

[0058] When the pressure inside the filtration container exceeds the set value (e.g., below -0.08 MPa), atmospheric pressure acts on the ball 330, causing the spring 340 to compress more. The ball 330 moves toward the inside of the pressure limiting channel 350, releasing the blockage on the outer port of the pressure limiting channel 350. External air can then enter the pressure limiting channel 350, then the fluid channel 110, and finally the filtration container to compensate for the pressure inside the filtration container.

[0059] When the pressure inside the filtration container is within the set range, the pressure difference between atmospheric pressure and the filtration container is insufficient to further compress the spring 340, so the ball 330 remains in the position of blocking the outer port of the pressure limiting channel 350.

[0060] Example 2:

[0061] Key reference Figure 3 and Figure 4 In this embodiment, both the switching valve core 200 and the pressure limiting valve core are directly mounted on the integrated valve body 100, but they are staggered.

[0062] Specifically, the second valve chamber 310 and the first valve chamber 210 are offset from each other along the axial direction of the fluid channel 110. The structure and working principle of the pressure limiting valve core are the same as in Example 1, and will not be repeated here.

[0063] Example 3:

[0064] Key reference Figure 5In this embodiment, the switching valve core 200 and the pressure limiting valve core are also directly mounted on the integrated valve body 100, but they are positioned opposite each other, and the structure of the switching valve core 200 has also been adjusted based on embodiment 2.

[0065] Specifically, the second valve chamber 310 and the first valve chamber 210 are positioned opposite each other along the axial direction of the fluid channel 110. The second valve chamber 310 is directly connected to the first valve chamber 210, and a flow channel 230 is provided on the end face of the switch valve core 200 facing the second valve chamber 310. The two ports of the flow channel 230 are respectively connected to the switch flow channel 220 and the first valve chamber 210.

[0066] When the pressure inside the filtration container exceeds the set value, the pressure difference between atmospheric pressure and the filtration container increases, causing the spring 340 to be further compressed. The ball 330 moves toward the inside of the pressure limiting channel 350, releasing the blockage on the outer port of the pressure limiting channel 350. External air can then enter the pressure limiting channel 350, and subsequently enter the fluid channel 110, and finally enter the filtration container to compensate for the pressure inside the filtration container.

[0067] Example 4:

[0068] Key reference Figure 6 In this embodiment, the switching valve core 200 and the pressure limiting valve core are also staggered on the integrated valve body 100. The structure of the switching valve core 200 is the same as that in embodiment 2, but the structure of the pressure limiting valve core is different from that in embodiment 2.

[0069] Specifically, the second valve chamber 310 and the first valve chamber 210 are also offset from each other along the axial direction of the fluid channel 110. However, the second valve chamber 310 penetrates the integrated valve body 100. The second valve chamber 310 has a first port and a second port that communicate with the external atmosphere. The inner diameter of the second port of the second valve chamber 310 is smaller than the inner diameter of the middle part of the second valve chamber 310.

[0070] The pressure-limiting valve core body 320 is inserted into the first port of the second valve cavity 310, and the ball 330 is located at the second port of the second valve cavity 310. The diameter of the ball 330 is larger than the inner diameter of the second port of the second valve cavity 310. The two ends of the spring 340 abut against the ball 330 and the pressure-limiting valve core body 320 respectively. Under the elastic force of the spring 340, the ball 330 abuts against the second port of the second valve cavity 310. Furthermore, a groove is formed on the end face of the pressure-limiting valve core body 320 facing the spring for the end of the spring to be inserted.

[0071] When the negative pressure inside the filtration container exceeds the set value, the pressure difference between atmospheric pressure and the pressure inside the container increases, causing the spring 340 to be further compressed. The ball 330 moves towards the pressure limiting valve core body 320, releasing the blockage on the second port of the second valve chamber 310, allowing atmospheric air to enter the fluid channel 110 through the second valve chamber 310 to compensate for the container pressure.

[0072] It should be noted that the contact surfaces between the switching valve core 200 and the first valve chamber 210, as well as the contact surfaces between the pressure-limiting valve core body 320 and the second valve chamber 310, should be sealed to ensure that fluid can only enter and exit through designated channels. Specifically, sealing rings are provided on the contact surfaces between the switching valve core 200 and the first valve chamber 210, as well as on the contact surfaces between the pressure-limiting valve core body 320 and the second valve chamber 310. Figure 1 In the first valve chamber, the sealing ring 400 is embedded in the cavity wall of the first valve chamber and is squeezed between the cavity wall of the first valve chamber and the circumferential side wall of the switch valve core.

[0073] In a preferred embodiment, the pressure-limiting valve core body 320 is threadedly connected to the second valve chamber 310. Rotating the pressure-limiting valve core body 320 allows it to move closer to or further away from the ball 330, thus adjusting the initial compression of the spring 340 and setting the negative pressure range required for normal operation of the filtration container. Typically, a groove is provided at the end of the pressure-limiting valve core body 320, into which a screwdriver can be inserted for easy rotation.

[0074] In the description of this utility model, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0075] In this utility model, unless otherwise explicitly specified and limited, the terms "setting," "installing," "connecting," "linking," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0076] Any aspects of this utility model not described in detail are known to those skilled in the art.

Claims

1. A negative pressure integrated valve with a switching function, comprising an integrated valve body, wherein a fluid channel is provided through the integrated valve body, and the two ports of the fluid channel respectively constitute a first air inlet and a second air inlet, characterized in that, The integrated valve body is provided with a switching valve core and a pressure limiting valve core; The integrated valve body has a first valve chamber, which is connected to a fluid channel. One end of the switch valve core is inserted into the first valve chamber, and the switch valve core is used to control the opening and closing of the fluid channel. A second valve chamber is provided on the pressure limiting valve core or the integrated valve body. The second valve chamber has an external port that communicates with the external atmosphere and an internal port that communicates directly or indirectly with the fluid channel. The pressure limiting valve core is inserted into the second valve chamber. The pressure limiting valve core is used to control the connection and disconnection between the fluid channel and the external atmosphere according to the pressure in the fluid channel.

2. The negative pressure integrated valve with switching function according to claim 1, characterized in that, A switching flow channel is provided through the end of the switching valve core inserted into the first valve chamber. The switching valve core can rotate relative to the first valve chamber. The rotation axis of the switching valve core is perpendicular to the axis of the fluid channel and the switching flow channel. During the rotation of the switching valve core, the switching flow channel is either connected to or disconnected from the fluid channel.

3. The negative pressure integrated valve with switching function according to claim 1, characterized in that, The pressure limiting valve core includes a pressure limiting valve core body, a ball, and a spring.

4. The negative pressure integrated valve with switching function according to claim 3, characterized in that, When the second valve chamber is located on the switch valve core, the outer port of the second valve chamber is connected to the external atmosphere, and the inner port of the second valve chamber is connected to the switch flow channel. A pressure-limiting flow channel is formed through the pressure-limiting valve core body. The pressure-limiting flow channel has an outer port that communicates with the external atmosphere and an inner port that communicates with the second valve chamber. The inner diameter of the outer port of the pressure-limiting flow channel is smaller than the inner diameter of the middle part of the pressure-limiting flow channel. The ball is positioned inside the pressure limiting channel and close to the outer port of the pressure limiting channel. The diameter of the ball is larger than the inner diameter of the outer port of the pressure limiting channel. The two ends of the spring abut against the cavity wall around the ball and the inner port of the second valve cavity, respectively. Under the action of the spring force, the ball abuts against the outer port of the pressure limiting channel.

5. The negative pressure integrated valve with switching function according to claim 3, characterized in that, When the second valve chamber is located on the integrated valve body, the second valve chamber and the first valve chamber are offset from each other or directly opposite each other along the axial direction of the fluid channel.

6. The negative pressure integrated valve with switching function according to claim 5, characterized in that, A pressure-limiting flow channel is formed through the pressure-limiting valve core body. The pressure-limiting flow channel has an outer port that communicates with the external atmosphere and an inner port that communicates with the second valve chamber. The inner diameter of the outer port of the pressure-limiting flow channel is smaller than the inner diameter of the middle part of the pressure-limiting flow channel. The ball is positioned inside the pressure limiting channel and close to the outer port of the pressure limiting channel. The diameter of the ball is larger than the inner diameter of the outer port of the pressure limiting channel. The two ends of the spring abut against the cavity wall around the ball and the inner port of the second valve cavity, respectively. Under the action of the spring force, the ball abuts against the outer port of the pressure limiting channel.

7. The negative pressure integrated valve with switching function according to claim 5, characterized in that, When the second valve chamber and the first valve chamber are offset from each other along the axial direction of the fluid channel, the second valve chamber penetrates the integrated valve body. The second valve chamber has a first port and a second port that communicate with the external atmosphere. The inner diameter of the second port of the second valve chamber is smaller than the inner diameter of the middle part of the second valve chamber. The pressure-limiting valve core body is inserted at the first port of the second valve cavity, and the ball is located at the second port of the second valve cavity. The diameter of the ball is larger than the inner diameter of the second port of the second valve cavity. The two ends of the spring abut against the ball and the pressure-limiting valve core body respectively. Under the action of the spring force, the ball abuts against the second port of the second valve cavity.

8. The negative pressure integrated valve with switching function according to claim 5, characterized in that, When the second valve chamber and the first valve chamber are directly opposite each other along the axial direction of the fluid channel, the second valve chamber and the first valve chamber are directly connected. A flow channel is provided on the end face of the switch valve core facing the second valve chamber, and the two ports of the flow channel are respectively connected to the switch flow channel and the first valve chamber.

9. The negative pressure integrated valve with switching function according to claim 1, characterized in that, Sealing rings are provided on the contact surface between the switching valve core and the first valve chamber, as well as on the contact surface between the pressure limiting valve core body and the second valve chamber.

10. The negative pressure integrated valve with switching function according to claim 1, characterized in that, The pressure relief valve core body is threadedly connected to the second valve chamber.

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