Full-diameter slot-shaped box type uniform-speed fluid flow measuring device
By using a full-diameter slotted box structure and a vertical pressure tap design, the problems of easy clogging and low measurement accuracy of bar-type differential pressure elements are solved, enabling high-precision flow measurement under various pipeline conditions, and making it suitable for gas and liquid flow measurement.
Patent Information
- Application Number
- CN202520581543.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-31
- Publication Date
- 2026-01-30
- Estimated Expiration
- 2035-03-31
AI Technical Summary
Existing Bar-type differential pressure elements are prone to clogging and have low measurement accuracy when measuring gas flow, especially in short straight pipe sections or bends, where the error is large, and the requirements for the straightness of the pipe being measured are high.
It adopts a full-diameter slotted box structure, including a slotted averaging box, a pressure lead-out main pipe inside the averaging box, a pressure lead-out pipe at the exhaust slot of the averaging box, a slotted air inlet and an air outlet of the averaging box. By setting a flat box inside the pipe being tested, the mixing space is increased, the number of pressure sensing holes is increased, and the pressure-sensing pipes are arranged vertically or at a large angle to prevent dust accumulation.
It solves the problem of easy clogging of bar-type products, improves measurement accuracy, reduces the requirement for straight pipe sections, is suitable for various pipeline routes, and can achieve accurate measurement even in the absence of straight pipe sections. It is suitable for gas and liquid flow measurement.
Smart Images
Figure CN223856530U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to fluid flow measuring device technical field especially a full diameter strip gap box type uniform velocity fluid flow measuring device. BACKGROUND
[0002] At present, the domestic bar type differential pressure element is widely used in various industries for measuring gas flow. The bar type differential pressure element mainly includes the domestic Anniu bar, the imported Vipor bar from the United States and the imported Delta bar from Germany. The measuring principle of the bar type differential pressure element is actually based on the measuring principle of the flute-shaped pipe. One pipe has several pressure sensing holes on the windward surface. The positive pressure in the pressure sensing pipe, the static pressure (also known as negative pressure) and the negative pressure in the pipeline are uniformly output to the differential pressure transmitter through the respective mother pipes after being uniformly distributed, and the size of the differential pressure reflects the size of the gas flow in the pipe. Figure 1 is a structural schematic diagram of a common bar type flowmeter. Figure 2 is a sectional view schematic diagram of a common bar type flowmeter.
[0003] Through the application tracking and analysis of the existing bar type products, it is found that the bar type products still have the following defects in the application process: a. The bar type product has a higher requirement for the straight pipe section of the measured air duct. When the straight pipe section is short, the speed distribution on the same end surface in the measured pipeline will cause a large deviation. At this time, since the number of measurement points on the windward surface of the bar type product is too small, and the diameter of the measurement mother pipe is relatively thin, the pressure at each point measured by each sensing hole cannot be uniformly distributed in the measurement mother pipe. Moreover, the pressure output of the bar type is at one end of the measurement pipe. Usually, the output pressure at this time is the average value of the sensing holes near the output end, rather than the average pressure sensed by the entire mother pipe. This causes a large error in measurement. b. When encountering dust-containing airflow, dust can enter the measurement mother pipe through the pressure sensing hole. The dust entering the mother pipe cannot be removed and will accumulate in the pipe. The more the accumulation, the more the accumulation. After a period of time, the entire measurement mother pipe will be blocked. In order to ensure use, maintenance personnel have to periodically or irregularly blow the measurement device with compressed air. The maintenance workload is large, and most of the accumulated dust in the mother pipe cannot be blown out after a long time. INVENTION CONTENTS
[0004] In order to overcome the shortcomings of the existing bar type products, the utility model provides a full diameter strip gap box type uniform velocity fluid flow measuring device.
[0005] The utility model discloses a technical scheme that solves its technical problems is: a kind of full-diameter strip gap shape box type uniform velocity fluid flow measuring device, including the strip gap shape uniform velocity box being arranged in the pipeline to be measured, uniform velocity box inner pressure lead-out main pipe, uniform velocity box exhaust strip gap mouth place pressure lead-out pipe, uniform velocity box strip gap shape air inlet and uniform velocity box strip gap shape air outlet;The strip gap shape uniform velocity box is arranged in the pipeline to be measured, is the flat box of height D, width H1, length L, and height D is same with the diameter of the pipeline to be measured, windward face is equipped with the uniform velocity box strip gap shape air inlet of height D, width H1, and the upper, middle, lower position of inner along height direction is respectively provided not less than three positive pressure measuring points and is connected to uniform velocity box inner pressure lead-out main pipe by positive lead pressure pipe;Uniform velocity box strip gap shape air outlet is opened on the strip gap shape uniform velocity box, and the uniform velocity box strip gap shape air outlet is used to exhaust the airflow into the strip gap shape uniform velocity box, and uniform velocity box strip gap shape air outlet is arranged not less than three negative pressure measuring points in the position avoiding airflow impact and is connected to uniform velocity box exhaust strip gap mouth place pressure lead-out pipe by negative lead pressure pipe;Its characterized in that, the ratio of the width of uniform velocity box strip gap shape air outlet and uniform velocity box air inlet H2 / H1=0.15~0.25, the ratio of the width and height of strip gap shape uniform velocity box H1 / D=0.065~0.110.
[0006] According to another embodiment of the utility model, further include, the upper part average gas flow rate in the pipeline to be measured is V 上 , and the lower part average gas flow rate is V 下 ;The ratio of the length and height of strip gap shape uniform velocity box L / D increases with the increase of flow rate distribution value V 上 / V 下 .
[0007] According to another embodiment of the utility model, further include, the positive lead pressure pipe and negative lead pressure pipe are perpendicular to ground or form the angle between 45°~90° with ground.
[0008] According to another embodiment of the utility model, further include, the section of the pipeline to be measured is circular or rectangular.
[0009] According to another embodiment of the utility model, further include, when the pipeline to be measured is elbow, positive pressure measuring point is arranged at 45 ° center line of elbow, and negative pressure measuring point is arranged at left, middle, right position in the diameter direction of downstream pipeline, wherein, uniform velocity box strip gap shape air inlet is in elbow horizontal section and enters elbow, and uniform velocity box strip gap shape air outlet is in the pipeline vertically downward after passing through elbow.
[0010] According to another embodiment of the utility model, further include, when uniform velocity box strip gap shape air outlet is installed on the side of uniform velocity box, the bottom surface of strip gap shape uniform velocity box is inclined plane, and uniform velocity box strip gap shape air outlet is arranged at low position of inclined plane and is guided.
[0011] According to another embodiment of the utility model, further include, the uniform speed box strip seam shape air outlet is set in strip seam shape uniform speed box bottom surface and the corresponding windward surface, the strip seam shape uniform speed box bottom surface forms the symmetrical inclined plane to the inside sudden change.
[0012] The beneficial effect of the utility model is that the "full-diameter strip seam box type uniform speed fluid flow measuring device" solves the problem that the measuring element, especially the bar type product measuring element, is easy to block in the current industrial application, and simultaneously greatly reduces the requirement for the straight pipe section of the measured pipeline due to the unique measuring principle and structure, greatly improves the measuring precision. Even in the case of no straight pipe section but only elbow, accurate measurement of the fluid flow in the pipeline can be realized, which has strong flexibility in arrangement and can be applied to any direction pipeline. The structure of the utility model is only for the structure when the measured pipeline is a circular pipeline. The structure can be completely applied to the measurement when the cross section of the measured pipeline is rectangular. In addition, the principle and structure of the utility model can be completely applied to other fluids such as water and oil, especially to dust-containing gas and dirt-containing liquid. The replaceable measuring instrument is not only limited to bar type measuring instrument, but can completely replace other fluid flow measuring instruments such as Venturi, orifice and long diameter nozzle. BRIEF DESCRIPTION OF DRAWINGS
[0013] The utility model is further illustrated below in combination with the drawings and examples.
[0014] Figure 1 It is a structural schematic view of a common bar type flowmeter;
[0015] Figure 2 It is a sectional view of a common bar type flowmeter;
[0016] Figure 3 It is a front view of the utility model applied to a horizontal measured pipeline;
[0017] Figure 4 It is a right view of the utility model applied to a horizontal measured pipeline;
[0018] Figure 5 It is a top view of the utility model applied to a horizontal measured pipeline;
[0019] Figure 6 It is a sectional view of Figure 5 ;
[0020] Figure 7 It is a front view of a vertical measured pipeline;
[0021] Figure 8 It is a right view of a vertical measured pipeline;
[0022] Figure 9 It is a top view of a vertical measured pipeline;
[0023] Figure 10 is the measurement structure front view of the measured pipeline as an elbow;
[0024] Figure 11 is the measurement structure left view of the measured pipeline as an elbow;
[0025] Figure 12 is the cross-sectional view of the dust-free airflow fluid structure.
[0026] Figure 1, measured pipeline, 2, slit uniform speed box, 3, uniform speed box in the pressure outlet pipe, 4, uniform speed box exhaust slit mouth pressure outlet pipe, 5, uniform speed box slit inlet, 6, uniform speed box slit outlet. DETAILED DESCRIPTION
[0027] As Figures 3 to 12 is the structure diagram of the utility model, a full diameter slit uniform speed fluid flow measuring device, including the slit uniform speed box 2 that sets in the measured pipeline 1, the uniform speed box in the pressure outlet pipe 3, the uniform speed box exhaust slit mouth pressure outlet pipe 4, the uniform speed box slit inlet 5 and the uniform speed box slit outlet 6 of uniform speed box; The slit uniform speed box 2 is arranged in the measured pipeline 1, is the flat box of height D, width H1, length L, and height D is same with the diameter of the measured pipeline 1, the windward face is equipped with the slit uniform speed box 5 of height D, width H1, and the upper, middle, lower positions of inner along height direction are provided not less than three positive pressure measuring points and are connected to the uniform speed box in the pressure outlet pipe 3 by positive pressure lead pipe; The slit uniform speed box 2 is opened on the slit uniform speed box 6 of height D, width H2 of the outlet of uniform speed box; The slit uniform speed box 6 is used to discharge the airflow that enters the slit uniform speed box 2, and not less than three negative pressure measuring points are provided at the position avoiding airflow impact around the slit uniform speed box 6 and are connected to the uniform speed box exhaust slit mouth pressure outlet pipe 4 by negative pressure lead pipe; Its characterized in that, the ratio of the slit uniform speed box 6 and the uniform speed box inlet width H2 / H1=0.15~0.25, the ratio of the width and height of the slit uniform speed box 2 H1 / D=0.065~0.110.
[0028] Specifically, one of the reasons for the low accuracy of bar product measurement is that there are too many pressure sensing holes arranged along the straight direction. In principle, the more pressure sensing points, the better, as long as the pressures measured by the pressure sensing holes can be fully mixed and uniform in the bar product measurement mother pipe. In fact, the pressure sensing points of the bar product cannot be too many, because the pipe diameter of the measurement mother pipe is small, and the pressures measured by the pressure sensing holes cannot be fully uniform. In order to improve the measurement accuracy, the diameter of the measurement mother pipe must be increased, and the volume of the mixing chamber must be increased. However, the increase in diameter is also limited, because too large a diameter will affect the flow area of the measured pipeline 1. In order to increase the volume of the mixing chamber without increasing the flow area, the shape of the measurement pipe must be changed from a circular shape to a flat box shape, and the length of the airflow direction must be extended. Since there is enough mixing space, this provides the condition for increasing the number of pressure sensing holes on the windward surface. When there are enough pressure sensing holes, they almost become a slit. This is the process of the present application. Figure 3 、 Figure 4 、 Figure 5 and Figure 6 The structure of the present application applied to a horizontal measured pipeline is given. A slit-shaped uniform speed box 2 is arranged in the horizontal circular pipeline. The slit-shaped uniform speed box 2 is a flat box with a height equal to the straight diameter D of the measured pipeline 1 and a width H1. The windward surface of the slit-shaped uniform speed box 2 is a uniform speed box slit-shaped air inlet 5 with a height D and a width H1, and the upper, lower, left and right sides are sealed. The leeward surface is provided with a uniform speed box slit-shaped air outlet 6 with a height D and a width H2. When the gas in the measured pipeline 1 flows vertically to the slit-shaped uniform speed box 2, a pressure higher than the static pressure in the measured pipeline 1 will be generated in the slit-shaped uniform speed box 2 due to the larger inlet area than the outlet area of the slit-shaped uniform speed box 2. The pressure difference between the two can fully reflect the size of the gas flow in the measured pipeline 1. The larger the flow, the larger the pressure difference, and the size of the flow is proportional to the square root of the pressure difference. The gas flow in the measured pipeline 1 can be measured by leading the pressure inside and outside the slit-shaped uniform speed box 2 to the outside of the measured pipeline 1 through the pressure leading pipe. When arranging the pressure leading pipe, the height of the uniform speed box is considered to be relatively high, and the pressures at the upper and lower parts of the box may not be exactly the same. In order to further improve the measurement accuracy, three pressure output holes are arranged at the upper, middle and lower parts of the uniform speed box, and the three pressure leading pipes are connected to the pressure leading-out pipe 3 in the uniform speed box to output "+" pressure. Similarly, the pressure at the slit-shaped air outlet is also divided into upper, middle and lower parts to output pressure, which is then output as "-" pressure through the pressure leading-out pipe 4 at the slit-shaped air outlet after mixing. The three negative pressure leading-out points are arranged at the slit-shaped air outlet, but the pressure tapping hole should not be directly opposite to the air outlet and should not be impacted by the airflow, and should be arranged beside the air outlet. Due to the jetting action of the outlet airflow, a pressure lower than the static pressure in the pipeline will be generated beside the air outlet, and the pressure at this position is taken as the "-" pressure output, which can obtain a larger pressure difference and is beneficial to improve the measurement accuracy.
[0029] Specifically, in order to reduce the disturbance of the measuring device to the gas in the measured pipeline 1, reduce the flow resistance, the slit-shaped windward surface width H1 of the measuring device should not be too wide, but also not too narrow, too narrow will cause the flow speed in the box to be too low and cause dust accumulation in the box, and it has been proved that the ratio of the slit width H1 to the diameter D of the measured pipeline 1 is more reasonable in the range of 0.065-0.110; in order to prevent the flow speed in the uniform speed box from being too low to cause dust accumulation, on the one hand, the inlet width H1 cannot be too small, and on the other hand, the outlet width H2 also cannot be too small, but H2 also cannot be too large, because H2 is too large to cause no pressure difference between the inside and outside of the box, and the reasonable H2 / H1 should be in the range of 0.15-0.25.
[0030] According to another embodiment of the utility model, further include, the upper part average gas flow speed in measured pipeline 1 is V 上 , the lower part average gas flow speed is V 下 ; The ratio of the length and height of the slit-shaped uniform speed box 2 L / D increases with the increase of the flow speed distribution value V 上 / V 下 .
[0031] Specifically, the device of the application adopts slit-shaped inlet measurement in the diameter direction of the measured pipeline 1, in order to obtain accurate measurement accuracy, the gas flow entering the uniform speed box must be fully mixed, which requires the uniform speed box to have a larger mixing space, under the condition that the width H1 of the device is limited, only by prolonging the length L along the gas flow direction can it be realized, in principle, the longer the L is, the larger the mixing space is, and the better the mixing effect is. But in actual application, due to the limited length of the pipeline, it is impossible to design a very long L, but the length of L must have a minimum value, when the gas flow speed of the upper and lower parts of the same end surface in the measured pipeline 1 is the same, the required length is the shortest. A large number of test experiments show that the minimum value of L / D is 0.158, and as the gas flow deviation of the upper and lower parts of the measured pipeline 1 becomes larger, the value of L / D must also become larger to ensure sufficient mixing space. After a large number of experiments, the following table shows the minimum value of L / D under the multiple of the gas flow deviation of the upper and lower parts.
[0032]
[0033]
[0034] According to another embodiment of the utility model, further include, the positive pressure pipe and the negative pressure pipe are perpendicular to the ground or form an angle of 45°-90° with the ground.
[0035] Specifically, in order to ensure the performance of the device of the application is reliable, in addition to preventing the inside of the uniform speed box from being dusty, the output leading pipe should not be dusty and blocked, for this reason, when designing the pressure leading pipe of the device, all of them are arranged vertically to the ground or at a large angle with the ground, so that the dust will fall back to the measured air duct due to its own gravity.
[0036] According to another embodiment of the application, further comprising, the cross section of the measured pipeline 1 is circular or rectangular.
[0037] Specifically, the device structure of the application is almost applicable to any measured pipeline 1, whether the measured pipeline 1 is horizontal, vertical or inclined, can be used, and whether the slit of the device itself is vertical or horizontal is not affected, as long as the pressure leading pipe drawn from the device is arranged vertically or at a large angle upward. Figure 7 、 Figure 8 、 Figure 9 For the arrangement of the measured pipeline as a vertical pipeline.
[0038] According to another embodiment of the application, further comprising, when the measured pipeline 1 is an elbow, the positive pressure measuring point is arranged at the 45° center line of the elbow, and the negative pressure measuring point is arranged at the left, middle and right positions in the diameter direction of the downstream pipeline, wherein the slit-shaped air inlet 5 of the uniform speed box is arranged at the elbow horizontal section entering the elbow, and the slit-shaped air outlet 6 of the uniform speed box is arranged at the pipeline vertically downward after the elbow.
[0039] Specifically, the device structure of the application is almost applicable to any measured pipeline 1, whether the measured pipeline 1 is horizontal, vertical or inclined, can be used, and whether the slit of the device itself is vertical or horizontal is not affected, as long as the pressure leading pipe drawn from the device is arranged vertically or at a large angle upward. Figure 10 and Figure 11 is the measurement structure designed and arranged at the elbow, the air inlet is arranged at the elbow horizontal section entering the elbow, the air outlet is arranged at the pipeline vertically downward after the elbow, the three positive pressure measuring points are arranged at the part of the uniform speed box along the 45° center line of the elbow, the negative pressure measuring points are arranged at the left, middle and right positions along the diameter at the downward part of the outlet, and all of the positive and negative pressure leading pipes are arranged vertically to the ground or at a large angle with the ground.
[0040] According to another embodiment of the application, further comprising, as shown in Figure 6 , when the slit-shaped air outlet 6 of the uniform speed box is installed on the side surface of the uniform speed box, the bottom surface of the slit-shaped uniform speed box 2 is inclined, and the slit-shaped air outlet 6 of the uniform speed box is arranged at the low position of the inclined surface for guidance.
[0041] According to another embodiment of the application, further comprising, as shown in Figure 12As shown, the uniform speed box strip gap gas outlet 6 is arranged at the bottom surface of the strip gap uniform speed box 2 corresponding to the windward surface, and the bottom surface of the strip gap uniform speed box 2 is inwardly protruded to form symmetrical inclined surfaces.
[0042] Specifically, Figure 6 , Figure 12 As shown, the uniform speed box strip gap gas outlet 6 is arranged at the bottom surface of the strip gap uniform speed box 2 corresponding to the windward surface, and the bottom surface of the strip gap uniform speed box 2 is inwardly protruded to form symmetrical inclined surfaces.
[0043] Specifically, Figures 3 to 12 By way of example, the device is also applicable to various fluids.
[0044] Specific operation process: 1. Device installation: vertically place the strip gap uniform speed box 2 in the measured pipeline 1, ensure that the height D is consistent with the pipeline diameter, the width H1 of the windward surface air inlet meets H1 / D = 0.065-0.110, and the width H2 of the air outlet meets H2 / H1 = 0.15-0.25.
[0045] 2. Measurement point layout: positive pressure measurement point: at least three measurement points are arranged at the upper, middle and lower positions of the strip gap uniform speed box 2 along the height direction, connected to the uniform speed box internal pressure lead-out main pipe 3 through the positive pressure lead pipe, and output "+ pressure". Negative pressure measurement point: at least three measurement points are arranged beside the uniform speed box strip gap air outlet 6 to avoid the airflow impact area, connected to the uniform speed box exhaust strip gap outlet pipe 4 through the negative pressure lead pipe, and output "- pressure".
[0046] 3. Mixed space adjustment: according to the flow velocity ratio V 上 / V 下 of the upper and lower parts of the measured pipeline 1, adjust the ratio of the box length L to the height D according to the test data (for example, when V 上 / V 下 =1.0, L / D≥0.158, and when the flow velocity difference increases, L / D increases accordingly).
[0047] 4. Pressure lead pipe arrangement: the positive and negative pressure lead pipes are perpendicular to the ground or form an angle of 45-90° with the ground to prevent dust deposition and blockage.
[0048] 5. Elbow working condition adaptation: if the measured pipeline is an elbow, the positive pressure measuring point is arranged at the 45° center line of the elbow, and the negative pressure measuring point is arranged at the left, middle and right positions of the diameter direction of the downstream pipeline.
[0049] 6. Flow calculation: the pressure difference signals inside and outside the uniform speed box are collected by the differential pressure transmitter, and the output value is calibrated in combination with the flow speed distribution data; for the short straight pipe section or elbow working condition, the measurement result is dynamically corrected according to the preset L / D and V 上 / V 下 relationship table.
[0050] The above description is only illustrative in nature and is not limiting, and a person of ordinary skill in the art understands that many modifications, changes or equivalents can be made without departing from the spirit and scope defined by the appended claims, and all will fall within the protection scope of the utility model.
Claims
1. A full-diameter slot-type tank-type uniform flow fluid flow measuring device, comprising a slot-type uniform flow tank (2) arranged in a measured pipeline (1), a uniform flow tank internal pressure leading main pipe (3), a uniform flow tank exhaust slot opening pressure leading pipe (4), a uniform flow tank slot-type air inlet (5) and a uniform flow tank slot-type air outlet (6); the slot-type uniform flow tank (2) is arranged in the measured pipeline (1) as a flat tank with a height D, a width H1 and a length L, and the height D is the same as the diameter of the measured pipeline (1), the windward surface is provided with a uniform flow tank slot-type air inlet (5) with a height D and a width H1, not less than three positive pressure measuring points are arranged at the upper, middle and lower positions in the height direction and connected to the uniform flow tank internal pressure leading main pipe (3) through positive pressure leading pipes; the slot-type uniform flow tank (2) is provided with a uniform flow tank slot-type air outlet (6) with a height D and a width H2; the uniform flow tank slot-type air outlet (6) is used for discharging the airflow into the slot-type uniform flow tank (2), not less than three negative pressure measuring points are arranged at a position avoiding airflow impact beside the uniform flow tank slot-type air outlet (6) and connected to the uniform flow tank exhaust slot opening pressure leading pipe (4) through negative pressure leading pipes; characterized in that, The ratio of the width of the uniform speed box slit-shaped air outlet (6) to the width of the uniform speed box air inlet is H2 / H1=0.15-0.25, and the ratio of the width of the uniform speed box (2) to the height is H1 / D=0.065-0.
110.
2. The full diameter slotted flume flow measurement device of claim 1, wherein, The average gas flow velocity in the upper part of the measured pipeline (1) is V 上 , and the average gas flow velocity in the lower part is V 下 ; the length-to-height ratio L / D of the slit-shaped uniform velocity tank (2) increases with the flow velocity distribution value V 上 / V 下 .
3. The full diameter slotted flume flow measurement device of claim 1, wherein, The positive and negative pressure pipes are perpendicular to the ground or form an angle of 45-90 degrees with the ground.
4. The full diameter slotted flume flow measurement device of claim 1, wherein, The cross section of the measured pipeline (1) is circular or rectangular.
5. The full diameter slotted- tank type uniform flow fluid flow measuring device as recited in claim 1, wherein, When the measured pipeline (1) is a bend, the positive pressure measuring point is arranged at the 45-degree center line of the bend, and the negative pressure measuring point is arranged at the left, middle and right positions in the diameter direction of the downstream pipeline; wherein the uniform speed box slit-shaped air inlet (5) is arranged at the bend inlet of the horizontal section of the bend, and the uniform speed box slit-shaped air outlet (6) is arranged at the vertically downward pipeline after the bend.
6. The full diameter slotted- tank type uniform flow fluid flow measuring device as recited in claim 1, wherein, When the uniform speed box slit-shaped air outlet (6) is installed on the side of the uniform speed box, the bottom surface of the uniform speed box (2) is inclined, and the uniform speed box slit-shaped air outlet (6) is arranged at the low position of the inclined surface for guidance.
7. The full diameter slotted- tank type uniform flow fluid flow measuring device as recited in claim 1, wherein, When the uniform speed box slit-shaped air outlet (6) is arranged on the bottom surface of the uniform speed box (2) corresponding to the windward surface, the bottom surface of the uniform speed box (2) is inwardly suddenly changed to form symmetrical inclined surfaces.