Venturi tube for negative pressure foam system of fire fighting truck

Abstract

The utility model relates to a venturi tube for a negative pressure foam system of a fire fighting truck. The venturi tube comprises a nozzle, a receiving cavity, a mixing cavity and a diffuser which are sequentially connected and internally communicated, at least one part of the nozzle is located in the receiving cavity, and a first inlet is formed in the end, located outside the receiving cavity, of the nozzle; a second inlet is formed in the receiving cavity, and the receiving cavity is communicated with the outside through the second inlet; and an outlet of the diffuser is communicated with the outside. According to the venturi tube for the negative pressure foam system of the fire fighting truck, the spray nozzle, the receiving cavity, the mixing cavity and the diffuser are connected in sequence, the structure is simple, machining is easy, the venturi tubes with different sizes can be arranged according to different flow requirements, and the use requirement of different vehicle-mounted fire fighting water pump negative pressure foam systems is met.

Description

Technical Field

[0001] The utility model relates to the field of fire extinguishing, in particular to a Venturi tube for a negative pressure foam system of a fire truck. Background Art

[0002] The Venturi tubes used in existing vehicle-mounted foam proportioning systems are cumbersome in processing technology, expensive in price, and inconvenient in repair and maintenance. For the processing of common Venturi tubes, the flow rate of the jet pressure water is large and it cannot be used on small-flow fire pumps; moreover, they are large in volume and not easy to be installed on the pump pipelines of foam fire trucks. Summary of the Invention

[0003] Based on this, the purpose of the utility model is to provide a Venturi tube for a negative pressure foam system of a fire truck, which has the advantages of simple structure, stable performance and convenient installation.

[0004] A Venturi tube for a negative pressure foam system of a fire truck includes a nozzle, a receiving cavity, a mixing cavity and a diffuser which are connected in sequence and internally communicated; at least a part of the nozzle is located in the receiving cavity, and a first inlet is arranged at one end of the nozzle located outside the receiving cavity; a second inlet is arranged on the receiving cavity, and the receiving cavity is communicated with the outside through the second inlet; the outlet of the diffuser is communicated with the outside.

[0005] For the Venturi tube for a negative pressure foam system of the utility model, the nozzle, the receiving cavity, the mixing cavity and the diffuser are connected in sequence, and have a simple structure and are easy to process. Venturi tubes with different volume sizes can be set according to different flow requirements to meet the use of negative pressure foam systems of different vehicle-mounted fire pumps.

[0006] Further, the nozzle includes a connecting part and a boosting part; the boosting part is a conical tube, and the periphery of one end face of the connecting part is fixedly connected with the periphery of the end face with a larger cross-sectional area of the boosting part; the periphery of one end face of the receiving cavity is fixedly connected with the outer peripheral surface of the connecting part, so that the boosting part is located in the receiving cavity, and the periphery of the other end face of the boosting part is fixedly connected with the outer peripheral surface of the mixing cavity.

[0007] Further, the receiving cavity includes a receiving cavity tube and a joint; the boosting part is located in the receiving cavity tube; one end of the joint is fixedly connected with the receiving cavity tube, and the second inlet is arranged at the other end of the joint and is located outside the receiving cavity tube.

[0008] Further, the cross-sectional area of the receiving cavity tube is larger than the cross-sectional area of the end of the boosting part close to the connecting part. This makes the space in the receiving cavity tube sufficient and convenient for the secondary flow to enter the receiving cavity tube from the joint.

[0009] Further, the mixing chamber includes a mixing chamber tube and a contraction tube; one end surface periphery of the mixing chamber tube is fixedly connected to one end surface of the receiving chamber tube away from the connection part, and the other end surface periphery of the mixing chamber tube is fixedly connected to one end surface periphery of the diffuser; the contraction tube is located inside the receiving chamber tube, one end of the contraction tube is fixedly connected to the periphery of one end of the mixing chamber tube close to the receiving chamber tube, and the other end of the contraction tube faces the pressurizing part; the cross-sectional area of one end of the contraction tube close to the pressurizing part is larger than the cross-sectional area of one end of the contraction tube close to the mixing chamber tube.

[0010] Further, the periphery of one end of the contraction tube close to the pressurizing part abuts against the inner wall of the receiving chamber tube. This can prevent the secondary flow from forming a reverse flow impact when entering the receiving chamber tube from the joint, and the secondary flow can smoothly enter the mixing chamber tube to mix with the main flow.

[0011] Further, the inner wall surface of the contraction tube is an arc surface, and the arc surface protrudes towards the outside of the contraction tube. This can effectively reduce the impact of the main flow and the secondary flow in the receiving chamber tube.

[0012] Further, grooves are provided on the outer peripheral surfaces of the connection part, the joint and the diffuser. These are used for connecting with pipelines.

[0013] Further, the nozzle, the receiving chamber, the mixing chamber and the diffuser are connected by welding.

[0014] Further, the inner wall surfaces of the nozzle, the receiving chamber, the mixing chamber and the diffuser are smoothed.

[0015] For better understanding and implementation, the present utility model will be described in detail below with reference to the accompanying drawings. Description of the Drawings

[0016] Figure 1 This is a schematic structural diagram (cross-sectional view) of the venturi tube for the negative pressure foam system of a fire truck in this application.

[0017] In the figure: 1 - nozzle; 11 - connection part; 12 - pressurizing part; 2 - receiving chamber; 21 - receiving chamber tube; 22 - joint; 3 - mixing chamber; 31 - mixing chamber tube; 32 - contraction tube; 4 - diffuser. Detailed Embodiment

[0018] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.

[0019] In the description of the present utility model, it should be noted that the orientation or positional relationship indicated by the terms "vertical direction", "upper", "lower", "horizontal", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present utility model. In addition, "first", "second", "third", "fourth" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0020] In the description of the present utility model, it should also be noted that unless otherwise clearly specified and limited, the terms "set", "installed", "connected", "connected to" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection. It can be a mechanical connection or an electrical connection. It can be a direct connection or a connection through an intermediate medium. It can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0021] Please refer to Figure 1 , this application provides a Venturi tube for a negative pressure foam system of a fire truck, which includes a nozzle 1, a receiving chamber 2, a mixing chamber 3 and a diffuser 4 connected in sequence. One end of the nozzle 1 away from the receiving chamber 2 is provided with a first inlet, and the mixing chamber 3 is provided with a second inlet communicating with the outside.

[0022] During use, the main flow enters from the first inlet of the nozzle 1, and the secondary flow enters from the second inlet of the receiving chamber 2. After mixing in the mixing chamber 3, it flows out from the diffuser 4. In this embodiment, the main flow is the foam concentrate and the secondary flow is water.

[0023] The nozzle 1 includes a connecting portion 11 and a boosting portion 12. Further, the outer peripheral surface of the connecting portion 11 is provided with a groove for connecting with a pipeline. The boosting portion 12 is a conical tube, and the periphery of the end surface with a larger cross-sectional area of it is fixedly connected to the periphery of one end surface of the connecting portion 11. The first inlet is provided at the end surface of the connecting portion 11 away from the boosting portion 12.

[0024] The receiving chamber 2 includes a receiving chamber tube 21 and a joint 22. In this embodiment, the receiving chamber tube 21 is generally cylindrical. The periphery of one end surface of it is fixedly connected to the outer peripheral surface of the connecting portion 11 close to the boosting portion 12, and the boosting portion 12 is located inside the receiving chamber tube 21. The joint 22 is a circular tube, and the periphery of one end surface of it is fixedly connected to the outer peripheral surface of the receiving chamber tube 21. The second inlet is provided at the other end surface of it, located outside the receiving chamber tube 21. The inner wall surface of the joint 22 is connected to the inner wall surface of the receiving chamber tube 21, and the joint 22 communicates with the receiving chamber tube 21.

[0025] Further, a groove is provided on the outer peripheral surface of the joint 22 for connection with a pipeline.

[0026] Further, the cross-sectional area of the receiving cavity tube 21 is larger than the cross-sectional area of the pressurizing portion 12 at one end close to the connecting portion 11, so that there is enough space in the receiving cavity tube 21 to facilitate the secondary flow to enter the receiving cavity tube 21 from the joint 22. Preferably, the cross-sectional diameter of the receiving cavity tube 21 is greater than or equal to twice the cross-sectional diameter of the pressurizing portion 12 at one end close to the connecting portion 11.

[0027] Further, the joint 22 is disposed opposite to the outer side of the circumferential surface of the pressurizing portion 12 and close to the end of the pressurizing portion 12 away from the connecting portion 11, so that when the secondary flow enters the receiving cavity tube 21, it is prevented from flushing against the main flow, and the secondary flow enters the mixing cavity 3 along the outer side of the circumferential surface of the pressurizing portion 12, which is conducive to the mixing of the main flow and the secondary flow in the mixing cavity 3.

[0028] The mixing cavity 3 includes a mixing cavity tube 31 and a contraction tube 32. One end face periphery of the mixing cavity tube 31 is fixedly connected to the end face of the receiving cavity tube 21 away from the connecting portion 11, and the mixing cavity tube 31 communicates with the receiving cavity tube 21; the contraction tube 32 communicates with the mixing cavity tube 31 and is located in the receiving cavity tube 21. In this embodiment, the contraction tube 32 is a conical tube, and the periphery of the end with a smaller cross-sectional area is fixedly connected to the periphery of the mixing cavity tube 31 close to the receiving cavity tube 21, and the end with a larger cross-sectional area is disposed opposite to the pressurizing portion 12.

[0029] Further, the periphery of the end of the contraction tube 32 close to the pressurizing portion 12 abuts against the inner wall of the receiving cavity tube 21 to prevent the secondary flow from forming a backflow flush when entering the receiving cavity tube 21 from the joint 22, so that the secondary flow can smoothly enter the mixing cavity tube 31 to be mixed with the main flow.

[0030] Further, the inner wall surface of the contraction tube 32 is an arc surface that protrudes outward from the contraction tube 32, which can effectively reduce the flush between the main flow and the secondary flow in the receiving cavity tube 21.

[0031] One end face periphery of the diffuser 4 is fixedly connected to the end face periphery of the mixing cavity tube 31 away from the contraction tube 32, and a groove is provided on the outer peripheral surface of the other end for connection with a pipeline. The inner wall cross-section of the diffuser 4 gradually increases from the end close to the mixing cavity tube 31 to the end away from the mixing cavity tube 31. When the Venturi tube of the present application is in use, the pressure in the mixing cavity tube 31 is less than the pressure at the end of the contraction tube 32 away from the mixing cavity tube 31 and the pressure at the end of the diffuser 4 away from the mixing cavity tube 31, and greater than the pressure at the end of the pressurizing portion 12 away from the connecting portion 11, so that the main flow and the secondary flow are smoothly delivered into the mixing cavity tube 31 for mixing.

[0032] In this embodiment, the nozzle 1, the receiving chamber 2, the mixing chamber 3 and the diffuser 4 are connected by welding. In other embodiments, the nozzle 1, the receiving chamber 2, the mixing chamber 3 and the diffuser 4 are connected by threaded connection or other sealing connection methods. In this application, the nozzle 1, the receiving chamber 2, the mixing chamber 3 and the diffuser 4 are of a split design and are connected by welding, with simple structure, stable performance and convenient installation.

[0033] Further, the inner wall surface of the Venturi tube is smoothed, which is beneficial to controlling the fluid flow rate to reach the target value. The size of the Venturi tube can be set according to different flow rate requirements to meet the use of different on-vehicle fire pump negative pressure foam systems.

[0034] The above-described embodiments only represent several implementation manners of the present utility model, and the description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the utility model patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present utility model, several modifications and improvements can still be made, and the present utility model also intends to include these modifications and improvements.

Claims

1. A venturi tube for a negative pressure foam system of a fire truck, characterized in that: It includes a nozzle, a receiving chamber, a mixing chamber and a diffuser which are connected in sequence and internally communicated; at least a part of the nozzle is located in the receiving chamber, and a first inlet is provided at one end of the nozzle which is located outside the receiving chamber; a second inlet is provided on the receiving chamber, and the receiving chamber is communicated with the outside through the second inlet; and the diffuser outlet is communicated with the outside.

2. The venturi tube for the negative pressure foam system of a fire truck according to claim 1, characterized in that: The nozzle includes a connecting part and a boosting part; the boosting part is a conical tube, and the periphery of the end face of one end of the connecting part is fixedly connected to the periphery of the end face of the boosting part with a larger cross-sectional area; the periphery of the end face of one end of the receiving cavity is fixedly connected to the outer peripheral surface of the connecting part, so that the boosting part is located in the receiving cavity, and the periphery of the end face of the other end is fixedly connected to the outer peripheral surface of the mixing cavity.

3. The venturi tube for the negative pressure foam system of a fire truck according to claim 2, characterized in that: The receiving cavity includes a receiving cavity tube and a connector; the pressurizing part is located in the receiving cavity tube; one end of the connector is fixedly connected to the receiving cavity tube, and the second inlet is arranged at the other end of the connector, located outside the receiving cavity tube.

4. The venturi tube for the negative pressure foam system of a fire truck according to claim 3, characterized in that: The cross-sectional area of ​​the receiving cavity tube is larger than the cross-sectional area of ​​one end of the pressurizing portion close to the connecting portion.

5. The venturi tube for the negative pressure foam system of a fire truck according to any one of claims 3-4, characterized in that: The mixing chamber includes a mixing chamber tube and a shrinkage tube; the periphery of an end surface of one end of the mixing chamber tube is fixedly connected to the periphery of an end surface of the receiving chamber tube away from the connecting portion, and the periphery of the end surface of the other end is fixedly connected to the periphery of an end surface of the diffuser; the shrinkage tube is located in the receiving chamber tube, one end of which is fixedly connected to the periphery of an end of the mixing chamber tube close to the receiving chamber tube, and the other end of which is opposite to the boosting portion; the cross-sectional area of ​​one end of the shrinkage tube close to the boosting portion is greater than the cross-sectional area of ​​one end of the shrinkage tube close to the mixing chamber tube.

6. The venturi tube for the negative pressure foam system of a fire truck according to claim 5, characterized in that: The shrink tube is close to the pressurizing part and abuts against the inner wall of the receiving cavity tube.

7. The venturi tube for the negative pressure foam system of a fire truck according to claim 6, characterized in that: The inner wall surface of the shrinkable tube is an arc surface, and the arc surface is convex toward the outer side of the shrinkable tube.

8. The venturi tube for the negative pressure foam system of a fire truck according to claim 5, characterized in that: Grooves are arranged on the outer circumferential surfaces of the connecting portion, the joint and the diffuser.

9. The venturi tube for the negative pressure foam system of a fire truck according to claim 1, characterized in that: The nozzle, the receiving chamber, the mixing chamber and the diffuser are connected by welding.

10. The venturi tube for the negative pressure foam system of a fire truck according to claim 1, characterized in that: The inner wall surfaces of the nozzle, the receiving chamber, the mixing chamber and the diffuser are smoothed.

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