Wide-range differential pressure flowmeter

Abstract

The invention relates to the technical field of measuring equipment based on fluid pressure difference, in particular to a wide-range differential pressure flowmeter which comprises a valve body, and a cavity ball and a rotating shaft are arranged in the valve body. A throttling orifice plate I and a throttling orifice plate II are arranged on the side portion of the cavity ball, the throttling orifice plate I and the throttling orifice plate II are arranged on the side portion of the cavity ball in a 90-degree mode, an opening I is formed in the position, corresponding to the throttling orifice plate I, of the side portion of the cavity ball, an opening II is formed in the position, corresponding to the throttling orifice plate II, of the side portion of the cavity ball, and the aperture ratios of the throttling orifice plate I and the throttling orifice plate II are different. The lower portion of the rotating shaft is connected with the top of the cavity ball, the upper portion of the rotating shaft extends out of the valve body, and the rotating shaft is twisted to rotate the cavity ball. According to the flow meter, the rotatable cavity ball is adopted, the state of the cavity ball is adjusted according to the fluid flow, the measuring range ratio is obviously increased, and therefore the flow meter enables the pressure loss of a pipeline to be reduced, and the size of a straight pipe section is also reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of measurement devices based on fluid pressure difference, and specifically to a wide-range differential pressure flowmeter. Background Art

[0002] Differential pressure flowmeters are commonly used in scenarios such as petrochemical industry, water treatment, and heating systems that require precise flow measurement. By setting throttle elements (such as orifice plates, nozzles), when the fluid flows through, the flow cross-sectional area suddenly decreases and the flow velocity increases, forming a pressure difference. Using a differential pressure transmitter to measure the pressure difference on both sides of the throttle element, the flow rate can be calculated. The current differential pressure flowmeters have the following defects: 1. The range ratio of traditional orifice plate flowmeters is usually only 1:10, which cannot adapt to intermittent large-range flow changes, and has a large pressure loss, requiring a long straight pipe section and high installation requirements; 2. Although the balanced flowmeter reduces the pressure loss through a porous structure, a single orifice plate is still limited by a fixed opening ratio; 3. Existing variable diameter schemes (such as V-cone valves) require complex mechanical adjustment mechanisms, with slow response speed and easy jamming. Summary of the Invention

[0003] In order to solve the above problems, the present invention provides a wide-range differential pressure flowmeter, where the throttle element can rotate to achieve rapid switching between two orifice plates, increasing the range of the flowmeter. The technical solutions adopted by the present invention are as follows: A wide-range differential pressure flowmeter includes a valve body, and a cavity ball and a rotating shaft are arranged inside the valve body; On the side of the cavity ball, there are orifice plate I and orifice plate II. Orifice plate I and orifice plate II are arranged at 90° on the side of the cavity ball. At the position corresponding to orifice plate I on the side of the cavity ball, there is an opening I, and at the position corresponding to orifice plate II, there is an opening II. The opening ratios of orifice plate I and orifice plate II are different; The lower part of the rotating shaft is connected to the top of the cavity ball, and the upper part extends out of the valve body. By twisting the rotating shaft, the cavity ball rotates.

[0004] For the above wide-range differential pressure flowmeter, the valve body is set as valve body I and valve body II, and a flange connection is provided between valve body I and valve body II. The cavity ball is located inside valve body I or valve body II and close to the flange connection.

[0005] For the above wide-range differential pressure flowmeter, the opening ratio of orifice plate I is 20% - 30%, and the opening ratio of orifice plate II is 60% - 75%.

[0006] For the above wide-range differential pressure flowmeter, pressure taking cavities for connecting a differential pressure transmitter are respectively arranged on the valve body on both sides of the cavity ball. The pressure taking cavity is an annular cavity, and the inner side of the cavity communicates with the fluid channel of the valve body through one or a plurality of uniformly distributed through holes.

[0007] For the above wide-range differential pressure flowmeter, the number of the through holes is 3 to 6, and they are evenly distributed in a circle on the cross section of the pressure-taking cavity.

[0008] For the above wide-range differential pressure flowmeter, a support seat is provided at the lower end of the rotating shaft to connect the cavity ball, and a packing is provided at the connection between the rotating shaft and the valve body, and a gland is configured to press the packing.

[0009] The beneficial effects of the present invention are as follows: First, the flowmeter adopts a rotatable cavity ball, adjusts the state of the cavity ball according to the fluid flow rate, so that the range ratio is significantly improved. For this reason, the flowmeter reduces the pressure loss of the pipeline and also reduces the size of the straight pipe section, and can be widely applied to wide-range occasions such as petrochemical intermittent filling, semiconductor ultrapure water, and steam metering.

[0010] Second, the arrangement of the pressure-taking cavity and the through holes forms an annular pressure-taking structure, which can significantly improve the stability and accuracy of differential pressure measurement, and reduce the influence of flow field disturbance on the measurement result; the multi-through hole structure can reduce the deposition of particles and impurities in the medium at the pressure-taking place, extend the maintenance period; and can also rectify the distribution of the fluid velocity before throttling, further reducing the influence of flow field distortion on the measurement accuracy. Description of the Drawings

[0011] Figure 1 is a schematic diagram of the external structure of an embodiment of the present invention; Figure 2 is a schematic diagram of the internal structure of an embodiment of the present invention; Figure 3 is a schematic diagram of the cross section of the pressure-taking cavity of an embodiment of the present invention; Figure 4 and Figure 5 is a schematic diagram of the cavity ball structure of an embodiment of the present invention.

[0012] In the figure: 1 is valve body Ⅰ, 2 is valve body Ⅱ, 3 is rotating shaft, 4 is differential pressure transmitter, 5 is gland, 6 is cavity ball, 7 is packing, 8 is support seat, 9 is pressure-taking cavity, 10 is through hole, 61 is throttle orifice plate Ⅰ, 62 is throttle orifice plate Ⅱ, 63 is connecting groove, 64 is opening Ⅰ, 65 is opening Ⅱ. Detailed Embodiments

[0013] The technical solutions of the present invention will be described in detail below with reference to the drawings. The following embodiments are all illustrative and are intended to provide further description of the present application. Unless otherwise specified, all technical terms used have the same meaning as commonly understood by those skilled in the technical field to which the present application belongs. It should be noted that the terms used are only for describing specific embodiments and are not intended to limit the present application.

[0014] This embodiment is a wide-range differential pressure flowmeter, including a valve body, in which a cavity ball 6 and a rotating shaft 3 are provided. Combined with Figures 2 to 4 , a throttle orifice plate I 61 and a throttle orifice plate II 62 are provided on the side of the cavity ball 6. The throttle orifice plate I 61 and the throttle orifice plate II 62 are arranged at 90° on the side of the cavity ball 6. An opening I 64 is provided at the position corresponding to the throttle orifice plate I 61 on the side of the cavity ball 6, and an opening II 65 is provided at the position corresponding to the throttle orifice plate II 62. The opening ratios of the throttle orifice plate I 61 and the throttle orifice plate II 62 are different. Combined with Figure 2 , the number and / or aperture of the function holes on the throttle orifice plate I 61 and the throttle orifice plate II 62 are different.

[0015] The lower part of the rotating shaft 3 is connected to the top of the cavity ball 6, and the upper part extends out of the valve body. Turning the rotating shaft 3 makes the cavity ball 6 rotate. The rotating shaft 3 can use driving elements such as a servo motor, which is convenient for automatic control.

[0016] In this embodiment, the valve body is set as valve body I 1 and valve body II 2. A flange connection is provided between the valve body I 1 and the valve body II 2. The cavity ball 6 is located in the valve body II 2 (or can also be located in the valve body I 1) and is close to the flange connection, which is convenient for disassembly and replacement of the cavity ball 6. Generally, preferably, the fluid flows from the valve body I 1 to the valve body II 2, that is, the fluid first flows through the orifice plate of the cavity ball 6 and then flows out at the opening, so as to ensure the stability of the fluid and the accuracy of measurement; in some cases, it can also be appropriately adjusted so that the fluid first flows through the opening of the cavity ball 6 and then flows out at the orifice plate.

[0017] Such as Figure 3 shown, preferably, the opening ratio of the throttle orifice plate I 61 is 20 - 30%, and its function holes are symmetrically distributed in multiple holes. The opening ratio of the throttle orifice plate II 62 is 60 - 75%, and the aperture of its function holes is distributed in a star array and satisfies the Reynolds number > 10 5 .

[0018] On the valve body on both sides of the cavity ball 6, a meter connection part is respectively provided. Such as Figure 2 shown, the valve body I 1 and the valve body II 2 can be respectively connected to a pressure gauge 4 to read the differential pressure, or the two connection parts can be connected to a differential pressure transmitter, and the user can choose according to the needs.

[0019] Such as Figures 1 to 3 shown, on the valve body on both sides of the cavity ball 6, pressure-taking cavities 9 for connecting a differential pressure transmitter 4 are respectively provided. The diameter of the pressure-taking cavity 9 is larger than the diameter of the valve body. The pressure-taking cavity 9 is an annular cavity, and the inner side of the cavity is connected to the fluid channel of the valve body through at least one through hole 10. The number of the through holes 10 is 3 - 6, and they are evenly distributed in a circle on the cross-section of the pressure-taking cavity 9.

[0020] This structure of the pressure-taking chamber 9 and its through-hole 10 has the following advantages: ①Improve measurement accuracy: It can effectively average the pressure fluctuations in the flow field, reduce the local errors of single-point pressure-taking, and particularly in the working conditions where the flow velocity distribution is uneven or there are vortices, it can significantly improve the stability and accuracy of differential pressure measurement; ②Enhance anti-interference ability: The pressure equalization design of annular pressure-taking can reduce the influence of flow field disturbances (such as turbulence caused by insufficient straight pipe sections, elbows or valves) on the measurement results, and is especially suitable for complex working conditions (such as high-viscosity, impurity-containing or non-axisymmetric flow fields); ③Reduce the risk of blockage: Compared with single-point pressure-taking, the multi-through-hole structure of annular pressure-taking can reduce the deposition of particles and impurities in the medium at the pressure-taking ports, and is especially suitable for dirty media (such as coke oven gas, mud, etc.), extending the maintenance cycle; ④Optimize flow field rectification: The annular pressure-taking can rectify the distribution of the fluid velocity before throttling, and further reduce the influence of flow field distortion on the measurement accuracy.

[0021] A support seat 8 is provided at the lower end of the rotating shaft 3 to connect the cavity ball 6, and a packing 7 is provided at the connection between the rotating shaft 3 and the valve body, and a gland 5 is configured to press the packing 7.

[0022] When the flow rate continuously remains below 10% - 15% of the current range for 5 seconds, the cavity ball 6 rotates to the throttle orifice plate I 61; when the flow rate continuously remains above 80% - 85% of the current range for 3 seconds, the cavity ball 6 rotates to the throttle orifice plate II 62. For example, in the scenario of a DN50 water flow measurement system, it is preferred that the opening ratio of the throttle orifice plate I 61 is 25%, and there are four function holes, and the aperture of each function hole is Φ6.25mm (or the equivalent diameter of the function holes of the throttle orifice plate I 61 is 12.5mm), and the actual measurement range is 0.3802 - 3.802m 3 / h; it is preferred that the opening ratio of the throttle orifice plate II 62 is 72.864%, and there are five function holes, and the aperture of each function hole is Φ16.293mm (or the equivalent diameter of the function holes of the throttle orifice plate II 62 is 36.432mm), and the actual measurement range is 3.802 - 38.02m 3 / h, thus achieving a range ratio of 1:100. The signal reading, signal transmission, and automatic control system of this flowmeter can all be realized by using conventional technologies, and there are no obstacles in the control technology. It should be explained that the equivalent diameter refers to the diameter corresponding to when all the function hole areas on the throttle orifice plate are equivalent to one function hole.

[0023] In most cases, the cavity ball 6 is preferably made of 316L stainless steel (corrosion-resistant) or Hastelloy (high-temperature and high-pressure resistant), etc. In the scenario of a high-temperature steam system, the cavity ball 6 is preferably made of Inconel718 alloy, and the surfaces of the throttle orifice plate I 61 and the throttle orifice plate II 62 are sprayed with an Al2O3 ceramic layer. The throttle orifice plate I 61 and the throttle orifice plate II 62 can be laser-drilled and electro-polished, with an aperture tolerance of ±0.05mm and no burrs at the edges.

[0024] The seal between the cavity ball 6 and the valve body is selected appropriately according to different working conditions. For example, metal hard seal + flexible graphite ring can be adopted. For instance, silicon carbide ceramic coating (wear-resistant) and expanded graphite (elastic compensation) can be selected. Metal + ceramic composite seal can also be used. The high-temperature contact stress ≥ 50 MPa. These are all conventional seal structures and seal standards, ensuring no leakage under high and low pressure conditions.

[0025] The range ratio of this flowmeter can reach 1:100 (for example, when measuring water flow, the range of the original flowmeter can only measure 1 - 10 m 3 / h, and the range of this flowmeter can be extended to 1 - 100 m 3 / h). Therefore, this flowmeter reduces the pressure loss of the pipeline and also reduces the size of the straight pipe section, and can be widely applied to wide-range occasions such as petrochemical intermittent filling, semiconductor ultrapure water, and steam metering.

[0026] The above are only the preferred embodiments of this application. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the principle of this application, several changes or improvements can still be made, and these changes or improvements should also be regarded as the protection scope of this application.

Claims

1. A wide range differential pressure flowmeter, comprising a valve body, characterized in that: A cavity ball (6) and a rotating shaft (3) are provided in the valve body; A throttling orifice plate I (61) and a throttling orifice plate II (62) are provided on the side of the cavity ball (6), and the throttling orifice plate I (61) and the throttling orifice plate II (62) are arranged at 90 degrees on the side of the cavity ball (6), and an opening I (64) is provided at a position corresponding to the throttling orifice plate I (61) and an opening II (65) is provided at a position corresponding to the throttling orifice plate II (62) on the side of the cavity ball (6), and the throttling orifice plate I (61) and the throttling orifice plate II (62) have different opening rates; The lower part of the rotating shaft (3) is connected to the top of the cavity ball (6), and the upper part extends out of the valve body. The cavity ball (6) is rotated by turning the rotating shaft (3).

2. The wide range differential pressure flowmeter according to claim 1, characterized in that: The valve body is configured as a valve body I (1) and a valve body II (2), and a flange connection is configured between the valve body I (1) and the valve body II (2). The cavity ball (6) is located in the valve body I (1) or the valve body II (2) and is close to the flange connection.

3. The wide range differential pressure flowmeter according to claim 1, characterized in that: The opening rate of the throttling orifice plate I (61) is 20-30%, and the opening rate of the throttling orifice plate II (62) is 60-75%.

4. The wide range differential pressure flowmeter according to claim 1, characterized in that: Pressure-taking cavities (9) for connecting to a differential pressure transmitter (4) are respectively provided on the valve body on both sides of the cavity ball (6); the pressure-taking cavity (9) is an annular cavity and is connected to a fluid channel of the valve body through one or a plurality of evenly distributed through holes (10) on the inner side of the cavity.

5. The wide range differential pressure flowmeter according to claim 1, characterized in that: The number of the through holes (10) is 3 to 6, and they are evenly distributed in a circumferential manner on the cross section of the pressure taking cavity (9).

6. The wide range differential pressure flowmeter according to claim 1, characterized in that: A support seat (8) is provided at the lower end of the rotating shaft (3) to connect with the cavity ball (6); a packing (7) is provided at the connection between the rotating shaft (3) and the valve body, and a pressure cover (5) is configured to press the packing (7).

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