Low-loss high-precision cavitation proportioning mixer with asymmetric structure

Abstract

The invention discloses a low-loss high-precision cavitation proportioning mixer with an asymmetric structure, and belongs to the technical field of cavitation mixers.The asymmetric Venturi structure is formed by a contraction section, a throat pipe section, a liquid suction channel and a diffusion section, an inlet of the contraction section is a high-pressure water inlet connected with an upstream high-pressure water pipeline, and an outlet of the diffusion section is a mixed liquid outlet connected with an upstream high-pressure water pipeline. The valve is connected with a downstream pipeline; an inlet of the liquid suction channel is connected with the additive storage tank, the two sides of an outlet of the liquid suction channel are communicated with an outlet of the contraction section and an inlet of the throat pipe section respectively, the joint of the outlet of the contraction section and the outlet is higher than that of the inlet of the throat pipe section, and the diffusion section is in an asymmetric cone shape. A cavitation area is controlled in a local range by using an asymmetric structure, so that unnecessary energy loss is avoided, an electrified part and a moving part are not arranged, and the device has the advantages of intrinsic safety, high stability, small pressure loss, simple structure, high reliability and low cost.

Description

Technical Field

[0001] The invention relates to the technical field of cavitation mixers in safety engineering, in particular to a low-loss and high-precision cavitation ratio mixer with an asymmetric structure. Background Art

[0002] In safety accidents such as fire, dust pollution, and leakage of hazardous chemicals, foam fire extinguishing technology, foam dust reduction technology, and multi-component water spraying are widely used in accident disposal. The above technologies all require the use of a proportioning mixer to achieve the continuous addition of additives such as foaming additives, detergents, and dust removal additives.

[0003] Since the mixing ratio of fire extinguishing, decontamination and dust removal additives is usually low (0.3%-6%), the proportioning mixer is required to have high precision, strong stability and small pressure loss, so as to ensure the stable application effect of foam or multi-component water mist, sufficient application time and application power. The characteristics of existing related patents are analyzed as follows: (CN202410160566.4, an environmentally friendly foam proportioning mixing device) and (CN202410453347.5, a heptafluoropropane foam proportioning mixing system), which have complex structures, contain live parts and moving mechanisms, and have problems such as large size, heavy weight and high cost. (CN202322221004.X, an adjustable pressure-type foam proportioning mixer) uses moving parts and airbag-type liquid storage tanks to achieve the proportioning function, but has the problems of weak durability, complex structure, large size and high cost; (CN202322968576.4, a foam proportioning mixer for fire hoses) uses a Venturi structure to generate negative pressure to inhale additives, (CN201110130367.1, an automatic foaming agent adding device) and (CN201210376347.7, a pneumatic jet-type proportioning foaming device) use a jet pump structure to generate negative pressure to inhale additives. These two types of devices have the advantages of simple structure, small size, intrinsic safety and low cost. However, the liquid absorption amount of this device will change with the downstream pressure, and the solution has a large resistance loss in the mixing process of this device, which will lead to insufficient downstream delivery pressure.

[0004] At the scene of an accident, flammable and explosive gases and dust can easily spread to the vicinity of the treatment agent application equipment. The equipment itself needs to have explosion-proof properties. Therefore, a hydraulic liquid suction device is more suitable as a proportional mixer for accident treatment agent application equipment. However, the liquid suction volume of various existing hydraulic liquid suction devices will be affected by downstream pressure fluctuations, and the energy loss in the liquid suction process needs to be reduced. Summary of the invention

[0005] In view of the above-mentioned shortcomings and deficiencies, the present invention provides a low-loss and high-precision cavitation ratio mixer with an asymmetric structure, which utilizes the asymmetric structure to control the cavitation area within a local range, thereby avoiding unnecessary energy loss.

[0006] In order to achieve the above-mentioned purpose, the main technical scheme adopted by the present invention is: a low-loss and high-precision cavitation proportion mixer with an asymmetric structure, including a contraction section, a throat section, a suction channel and an asymmetric diffusion section, the contraction section, the throat section, the suction channel and the diffusion section constitute an asymmetric Venturi structure, the inlet of the contraction section is a high-pressure water inlet, connected to the upstream high-pressure water pipeline, the outlet of the diffusion section is a mixed liquid outlet, connected to the downstream pipeline; the inlet of the suction channel is connected to the additive storage tank, and the two sides of the outlet are respectively connected to the outlet of the contraction section and the inlet of the throat section, and the height of the connection with the outlet of the contraction section is higher than the connection with the inlet of the throat section, so that an asymmetric step is formed at the junction of the contraction section and the throat, and the ratio of the inner diameter of the throat section to the inner diameter of the outlet of the contraction section is between 1.05-1.2.

[0007] The inner flow channel of the non-diffuser section is an asymmetric conical cone with a horizontal upper end and a diffusion angle at the lower end. The ratio of the outlet inner diameter of the diffuser section to the outlet inner diameter of the contraction section is not less than 5, and the diffusion angle is 6°-10°.

[0008] The ratio of the inner diameter of the inlet of the contraction section to the inner diameter of the outlet of the contraction section is not less than 5, and the contraction angle is 15°-20°.

[0009] The ratio of the length of the throat section to the inner diameter of the outlet of the contraction section is 3-10.

[0010] The inlet of the contraction section is threadedly connected to the high-pressure water pipeline; the outlet of the asymmetric diffusion section is threadedly connected to the downstream pipeline; and the inlet of the liquid suction channel is threadedly connected to the additive storage tank.

[0011] The present invention has the following beneficial effects and advantages: The present invention forms an asymmetric step at the outlet of the contraction section and the inlet of the throat section, so that the high-speed water flow forms a violent turbulence on the step side. The low static pressure in the throat section and the turbulent zone on the step side can cause local cavitation of the liquid on the step side; the asymmetric structure controls the cavitation area in a local range, thereby avoiding unnecessary energy loss. In order to reduce the mechanical energy loss downstream of the throat section, the diffusion section of the present invention is set as an asymmetric gradual structure, and by controlling the range of the diffusion angle β, unnecessary pressure loss can be avoided. In addition, the present invention does not have live parts and moving parts, and has the advantages of intrinsic safety, high stability, small pressure loss, simple structure, high reliability and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a structural schematic diagram of the low-loss and high-precision cavitation ratio mixer of the asymmetric structure of the present invention; Figure 2 is a distribution diagram of cavitation bubbles in the throat section in the embodiment; Figure 3 This is a diagram of the pressure distribution of the throat section in the embodiment; Figure 4 Schematic diagram of the variation of the liquid suction ratio with the outlet-inlet pressure ratio in the embodiment.

[0013] Among them, 1-contraction section; 2-throat section; 3-liquid suction channel; 4-diffusion section; 5-high-pressure water inlet; 6-mixed liquid outlet; d1-inner diameter of high-pressure water inlet; d2-inner diameter of contraction section outlet; d3-inner diameter of throat; d4-inner diameter of mixed liquid outlet; L-throat length; α-contraction angle; β-diffusion angle. DETAILED DESCRIPTION

[0014] The present invention will be further described below in conjunction with the accompanying drawings. Figure 1 As shown, the present invention is a low-loss, high-precision cavitation proportion mixer with an asymmetric structure, comprising a contraction section, a throat section, a liquid suction channel and an asymmetric diffusion section. The contraction section, the throat section, the liquid suction channel and the diffusion section constitute an asymmetric Venturi structure. The inlet of the contraction section is a high-pressure water inlet, which is threadedly connected to the upstream high-pressure water pipeline. The outlet of the diffusion section is a mixed liquid outlet, which is threadedly connected to the downstream pipeline. The inlet of the liquid suction channel is threadedly connected to the additive storage tank, and the two sides of the outlet are respectively connected to the outlet of the contraction section and the inlet of the throat section, and the height of the connection with the outlet of the contraction section is higher than the connection with the inlet of the throat section; that is, the central axis of the contraction section and the central axis of the throat are not in the same straight line, so that an asymmetric step is formed at the junction of the contraction section and the throat, and the inner flow channel of the diffusion section is an asymmetric conical cone with a horizontal upper end and a diffusion angle at the lower end.

[0015] In this embodiment, the inner diameter d1 of the high-pressure water inlet is set to 20 mm, the contraction angle α is set to 17.5°, the diffusion angle β is set to 6°, the ratio of the inner diameter d1 of the high-pressure water inlet to the inner diameter d2 of the contraction section outlet is set to 6, the ratio of the length of the throat section to the inner diameter d2 of the contraction section outlet is set to, the ratio of the throat inner diameter d3 to the inner diameter d2 of the contraction section outlet is set to 1.05, and the ratio of the mixed liquid outlet inner diameter d4 of the diffusion section 4 to the inner diameter d2 of the contraction section outlet is set to 6.

[0016] When in use, after high-pressure water flows through the contraction section 1, the velocity pressure increases and the static pressure decreases, and negative pressure is generated in the throat section 2. The negative pressure in the throat 2 causes the additive to automatically enter the throat section from the suction channel 3 and mix with the water. After the mixed liquid enters the diffusion section 4, the static pressure rises as the inner diameter increases, driving the mixed liquid to continue to be transported to the downstream pipeline.

[0017] The present invention accelerates high-pressure water through the contraction section 1, forms a low static pressure zone in the throat section 2, and sets an asymmetric step at the outlet of the contraction section 1 and the inlet of the throat section 2, so that the high-speed water flow forms a violent turbulence on the step side. Under the combined action of the low static pressure in the throat section 2 and the turbulent zone on the step side, local cavitation can occur in the liquid on the step side.

[0018] The pressure value in the cavitation area can be maintained between -100kPa and -97kPa (close to vacuum), and water vapor bubbles are generated at room temperature. Even if the downstream pressure changes can change the size of the cavitation area, the pressure value of the area occupied by the cavitation bubbles remains close to vacuum. Therefore, the present invention sets the additive suction port at the step side at the outlet of the contraction section 1 and the inlet of the throat section 2. This area is very prone to cavitation (see Figure 2 ), which can ensure the pressure difference between the suction port and the additive tank is stable (see Figure 3 ), thereby ensuring a stable amount of liquid absorption.

[0019] Since the turbulent cavitation process will cause part of the mechanical energy to be converted into heat energy dissipation, the asymmetric structure adopted in the present invention can keep the cavitation zone near the suction port. Since the tube wall on the other side does not have a cross-sectional mutation, the cavitation behavior on the other side is suppressed (see Figure 2 ). The asymmetric structure controls the cavitation area to a local range, thereby avoiding unnecessary energy loss; in order to reduce the mechanical energy loss downstream of the throat section 2, the diffusion section of the present invention is set as an asymmetric gradual structure, and by controlling the range of the diffusion angle β, unnecessary pressure loss can be avoided.

[0020] The ratio of the suction flow rate to the high-pressure water flow rate was measured under different high-pressure water inlet pressures and mixed liquid outlet pressures, and the following results were obtained: Figure 4 The results are shown in Figure 2. It is only necessary to keep the ratio of the outlet pressure to the inlet pressure below 0.7 to keep the liquid absorption ratio highly stable and the pressure loss not exceeding 30%.

[0021] In addition, the present invention has no live parts and moving parts, and has the advantages of intrinsic safety, high stability, small pressure loss, simple structure, high reliability and low cost.

Claims

1. A low-loss, high-precision cavitation ratio mixer with an asymmetric structure, characterized in that: It includes a contraction section, a throat section, a liquid suction channel and an asymmetric diffusion section. The contraction section, the throat section, the liquid suction channel and the diffusion section constitute an asymmetric Venturi structure. The inlet of the contraction section is a high-pressure water inlet, which is connected to the upstream high-pressure water pipeline. The outlet of the diffusion section is a mixed liquid outlet, which is connected to the downstream pipeline. The inlet of the liquid suction channel is connected to the additive storage tank, and the two sides of the outlet are respectively connected to the outlet of the contraction section and the inlet of the throat section, and the height of the connection with the outlet of the contraction section is higher than the connection with the inlet of the throat section, so that an asymmetric step is formed at the junction of the contraction section and the throat, and the ratio of the inner diameter of the throat section to the inner diameter of the outlet of the contraction section is between 1.05 and 1.

2.

2. A low-loss and high-precision cavitation proportion mixer with an asymmetric structure according to claim 1, characterized in that: The inner flow channel of the diffusion section is an asymmetric conical cone with a horizontal upper end and a diffusion angle at the lower end. The ratio of the outlet inner diameter of the diffusion section to the outlet inner diameter of the contraction section is not less than 5, and the diffusion angle is 6°-10°.

3. A low-loss and high-precision cavitation proportion mixer with an asymmetric structure according to claim 1, characterized in that: The ratio of the inlet inner diameter of the contraction section to the outlet inner diameter of the contraction section is not less than 5, and the contraction angle is 15°-20°.

4. The low-loss and high-precision cavitation proportion mixer with an asymmetric structure according to claim 1, characterized in that: The ratio of the length of the throat section to the inner diameter of the outlet of the contraction section is 3-10.

5. The low-loss and high-precision cavitation proportion mixer with an asymmetric structure according to claim 1, characterized in that: The inlet of the contraction section is connected to the high-pressure water pipeline thread or through a quick connector; the outlet of the asymmetric diffusion section is connected to the downstream pipeline thread or through a quick connector; the inlet of the suction channel is connected to the additive storage tank thread or through a quick connector.

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