阅读说明：本技术 一种新型文丘里管 (Novel venturi tube ) 是由 黄晗 于 2018-06-15 设计创作，主要内容包括：本发明公开了一种新型文丘里管,包括外文丘里管,套接在外文丘里管内的内文丘里管,以及套接在外文丘里管外侧、并通过翼板固定有前后端均设置有连接法兰的探测管道,所述外文丘里管和内文丘里管的截面几何中心线均与探测管道的截面几何中心线相重合,所述外文丘里管由前收缩管一、取压喉管一和后扩散管一顺次连接而成,所述内文丘里管由前收缩管二、取压喉管二和后扩散管二顺次连接而成。该文丘里管结构新颖,设计合理；体积小巧,便于搬运、运输；不造成不必要的流体压力损失；生产成本低,便于推广使用。(The invention discloses a novel Venturi tube, which comprises an outer Venturi tube, an inner Venturi tube sleeved in the outer Venturi tube, and a detection pipeline sleeved outside the outer Venturi tube and fixed with a front end and a rear end through wing plates, wherein the front end and the rear end of the detection pipeline are respectively provided with a connecting flange, the geometric center lines of the cross sections of the outer Venturi tube and the inner Venturi tube are respectively superposed with the geometric center line of the cross section of the detection pipeline, the outer Venturi tube is formed by sequentially connecting a front contraction tube I, a pressure taking throat tube I and a rear diffusion tube I, and the inner Venturi tube is formed by sequentially connecting a front contraction tube II, a pressure taking throat tube II and a rear diffusion tube II. The Venturi tube has novel structure and reasonable design; the volume is small, and the carrying and the transportation are convenient; unnecessary fluid pressure loss is not caused; low production cost and convenient popularization and use.)

1. A novel Venturi tube comprises an outer Venturi tube, an inner Venturi tube sleeved in the outer Venturi tube, and a detection pipeline sleeved outside the outer Venturi tube and fixed with a front end and a rear end through wing plates and provided with connecting flanges, and is characterized in that the cross-sectional geometric central lines of the outer Venturi tube and the inner Venturi tube are overlapped with the cross-sectional geometric central line of the detection pipeline, the outer Venturi tube is formed by sequentially connecting a first front contraction tube, a first pressure taking throat tube and a first rear diffusion tube, the inner Venturi tube is formed by sequentially connecting a second front contraction tube, a second pressure taking throat tube and a second rear diffusion tube, the first pressure taking throat tube and the second pressure taking throat tube are both circular pipe sections, the inlet end face of the second front contraction tube is positioned at the tail end of the first pressure taking throat tube, the outlet end face of the second rear diffusion tube is positioned inside the first rear diffusion tube, and a pressure taking hole is formed in the pressure taking throat tube of the inner Venturi tube, the upper side of the middle part of the pipe wall of the detection pipeline is provided with a low-end pressure taking ring chamber and a low-end pressure taking ring chamber interface which are communicated with the pressure taking hole, and the inner surfaces of the front contraction pipe I, the rear diffusion pipe I, the front contraction pipe II and the rear diffusion pipe II are hyperbolic or parabolic revolution surfaces; the curvature of the inner surface of the first front shrinkage pipe is larger than that of the inner surface of the first rear diffusion pipe, and the curvature of the inner surface of the second front shrinkage pipe is larger than that of the inner surface of the second rear diffusion pipe; an online detection interface is arranged on the lower side of the front end of the pipe wall of the detection pipeline, and a purging opening communicated with the low-end pressure taking ring chamber is arranged on the lower side of the pipe wall of the detection pipeline.

Technical Field

The invention relates to a fluid measuring device, in particular to a novel Venturi tube.

Background

At present, in the flow measurement of low-pressure large-pipe-diameter gas with low pressure, small flow and slow flow rate, such as gas, flue gas and other dirty media, an enterprise often adopts a common standard type throttling device, such as: the standard orifice plate metering has the following defects by adopting the standard orifice plate metering: 1. the measured medium pressure is low and sometimes has negative pressure, so that the medium flow in the pipeline is very small and the flow speed is very low, therefore, the measured differential pressure signal is very small, only a micro differential pressure transmitter can be selected, the micro differential pressure transmitter can easily cause zero drift, the measurement precision is low, the control is very difficult, and the cost of the micro differential pressure transmitter is very expensive; 2. the standard throttling device requires a very harsh installation position, generally requires that the diameter of a front straight pipeline is more than 10 times that of a pipeline, and the diameter of a rear straight pipeline is more than 5 times that of the pipeline, and when a fluid is measured, the pipeline is often provided with accessories such as a tee joint, an elbow and a valve, so that a very long straight pipeline section cannot be arranged on site to install the flowmeter; 3. in order to pursue measurement accuracy, only a differential pressure signal is generally amplified to achieve the measurement accuracy of a differential pressure transmitter, a throttling element is manually reduced, a differential pressure output signal is improved, and as a result, pressure loss of a pipeline is large, about 30% of pressure of a measured medium is lost, the loss is generally unrecoverable, and the requirement of energy conservation and emission reduction advocated by the state is not met.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provides a novel Venturi tube which is novel in structure and reasonable in design; the volume is small, and the carrying and the transportation are convenient; unnecessary fluid pressure loss is not caused; low production cost and convenient popularization and use.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a novel Venturi tube comprises an outer Venturi tube, an inner Venturi tube sleeved in the outer Venturi tube, and a detection pipeline which is sleeved outside the outer Venturi tube and is fixed with a front end and a rear end through wing plates and is provided with connecting flanges, the geometric center line of the cross section of the outer Venturi tube and the geometric center line of the cross section of the inner Venturi tube are coincident with the geometric center line of the cross section of the detection pipeline, the outer Venturi tube is formed by sequentially connecting a first front contraction tube, a first pressure taking throat tube and a first rear diffusion tube, the inner Venturi tube is formed by sequentially connecting a second front contraction tube, a second pressure taking throat tube and a second rear diffusion tube, the first pressure taking throat tube and the second pressure taking throat tube are circular pipe sections, the inlet end face of the second front contraction tube is located at the tail end of the first pressure taking throat tube, the outlet end face of the second rear diffusion tube is located inside the first rear diffusion tube, and a pressure taking hole is formed, the upper side of the middle part of the pipe wall of the detection pipeline is provided with a low-end pressure taking ring chamber and a low-end pressure taking ring chamber interface which are communicated with the pressure taking hole, and the inner surfaces of the front contraction pipe I, the rear diffusion pipe I, the front contraction pipe II and the rear diffusion pipe II are hyperbolic or parabolic revolution surfaces; the curvature of the inner surface of the first front shrinkage pipe is larger than that of the inner surface of the first rear diffusion pipe, and the curvature of the inner surface of the second front shrinkage pipe is larger than that of the inner surface of the second rear diffusion pipe; an online detection interface is arranged on the lower side of the front end of the pipe wall of the detection pipeline, and a purging opening communicated with the low-end pressure taking ring chamber is arranged on the lower side of the pipe wall of the detection pipeline.

Compared with the prior art, the invention has the following beneficial effects:

the invention has novel structure and reasonable design. The novel built-in double-venturi tube has a novel structure, the inlet end surface of the inner venturi tube is positioned at the tail end of the outer venturi tube pressure taking throat tube, and the pressure taking hole is formed in the pressure taking throat tube of the inner venturi tube, so that the fluid pressure at the pressure taking hole can be greatly increased through the design;

the invention has small volume and is convenient to transport. The novel built-in double venturi tube has small volume and light weight, and is very convenient to carry and transport;

the invention does not cause unnecessary fluid pressure loss. Through fluid mechanics theoretical analysis and a large number of wind tunnel experiments, the interiors of the front contraction pipe and the rear diffusion pipe of the novel built-in double-venturi pipe are hyperbolic or parabolic revolution surfaces, so that the fluid pressure loss is only about 3% of a differential pressure signal, and the pressure loss is greatly reduced compared with that of a common standard throttling device;

the invention has low production cost and is convenient for popularization and use. The novel built-in double-venturi tube is very multi-part and is very convenient to produce and purchase, so that the production cost is very low, and the popularization and the use are convenient.

Drawings

Fig. 1 is a front view of the present invention.

Fig. 2 is a sectional view a-a of fig. 1.

Figure 3 is a schematic diagram of the external venturi of the present invention.

Figure 4 is a schematic diagram of the structure of the venturi of the present invention.

Wherein, the names corresponding to the reference numbers are:

1-detecting a pipeline; 2-outer venturi tube; 21-front shrink tube one; 22-a pressure-taking throat pipe I; 23-rear diffusion tube one; 3-inner venturi tube; 31-front shrink tube two; 32-a second pressure-taking throat pipe; 33-rear diffusion tube II; 4-pressure tapping; 5-high-end pressure ring taking chamber; 6-high end pressure ring chamber interface; 7-low end pressure ring chamber; 8-low end pressure ring chamber interface; 9-online detection interface; 10-a purge port; 11-wing plate.

Detailed Description

The present invention will be further described with reference to the following description and examples, which include but are not limited to the following examples.

The novel concealed double-venturi tube shown in fig. 1-4 comprises a detection pipeline 1 with connecting flanges at the front and rear ends, wherein a high-end pressure ring taking chamber 5 and a high-end pressure ring taking chamber interface 6 are arranged on the upper side of the front end of the pipe wall of the detection pipeline 1; an outer Venturi tube 2 is fixed inside the detection pipeline 1 through a wing plate 11, an inner Venturi tube 3 is fixed inside the outer Venturi tube 2, and the geometric center lines of the sections of the outer Venturi tube 2 and the inner Venturi tube 3 are coincident with the geometric center line of the section of the detection pipeline 1; the outer Venturi tube 2 is formed by sequentially connecting a first front shrinkage tube 21, a first pressure taking throat tube 22 and a first rear diffusion tube 23, the inner Venturi tube 3 is formed by sequentially connecting a second front shrinkage tube 31, a second pressure taking throat tube 32 and a second rear diffusion tube 33, the first pressure taking throat tube 22 and the second pressure taking throat tube 32 are both circular tube sections, the inlet end face of the second front shrinkage tube 31 is positioned at the tail end of the first pressure taking throat tube 22, and the outlet end face of the second rear diffusion tube 33 is positioned inside the first rear diffusion tube 23; a pressure measuring hole 4 is formed in the pressure measuring throat of the inner Venturi tube 3, and a low-end pressure measuring ring chamber 7 and a low-end pressure measuring ring chamber interface 8 which are communicated with the pressure measuring hole 4 are arranged on the upper side of the middle of the tube wall of the detection pipeline 1; the inner surfaces of the front shrinkage pipe I21, the rear diffusion pipe I23, the front shrinkage pipe II 31 and the rear diffusion pipe II 33 are hyperbolic or parabolic revolution surfaces.

As shown in fig. 3 and 4, the inner surface of the front shrinkage pipe I21 has a curvature larger than that of the inner surface of the rear diffusion pipe I23, and the inner surface of the front shrinkage pipe II 31 has a curvature larger than that of the inner surface of the rear diffusion pipe II 33.

As shown in fig. 2, an online detection interface 9 is arranged on the lower side of the front end of the pipe wall of the detection pipeline 1, and a purge port 10 communicated with the low-end pressure-taking ring chamber 7 is arranged on the lower side of the pipe wall of the detection pipeline 1. The blowing port 10 can blow solid particles or dust in the low-end pressure extraction ring chamber 7 to prevent blockage

The working process of the novel built-in double-venturi tube of the invention is as follows: this novel two venturi combinations outside one in this two venturi of built-in adoption, the preceding two 31 entry end faces of shrink tube of interior venturi 3 are located outer venturi 2's the end of taking a pressure choke 22, when the fluid flows through outer venturi 2, preceding shrink tube 21 fluid is accelerated, the rectification, it is induced, make the flow velocity of fluid through outer venturi 2 inside obviously accelerate, and because outer venturi 2's the end of taking a pressure choke 22 is just in time linked together with inner venturi 3's preceding shrink tube two 31 entry end, inner venturi 3 carries out the acceleration once more to the fluid this moment, the rectification, carry out secondary acceleration effect to the fluid through outer venturi 2, it is bigger to make the flow velocity of fluid.

The pressure flowing through the high-end pressure taking ring chamber interface 6 and the low-end pressure taking ring chamber interface 8 of the built-in throttling device is measured by using a measuring device to form pressure difference, and the obtained pressure difference is combined with a fluid mechanics theory and a wind tunnel experiment to obtain a mathematical model between the pressure difference and fluid, so that the real flow in the pipeline is obtained.

The above-mentioned embodiment is only one of the preferred embodiments of the present invention, and should not be used to limit the scope of the present invention, but all the insubstantial modifications or changes made within the spirit and scope of the main design of the present invention, which still solve the technical problems consistent with the present invention, should be included in the scope of the present invention.