Wide-range differential pressure force flowmeter and differential pressure force flow measurement method thereof

Abstract

The application discloses a wide-range differential pressure force flowmeter and a differential pressure force flow measurement method thereof, and belongs to the technical field of differential pressure force measurement. The differential pressure force flowmeter comprises two differential pressure force transmitters with different ranges and steam-isolating pressure tapping elements connected with the differential pressure force transmitters, the steam-isolating pressure tapping elements are internally provided with a guide hole communicated with a steam guide pipe and an isolation liquid vertical hole, a sealing plug is arranged at the top end of the isolation liquid vertical hole, and the sealing plug can block and release steam in the isolation liquid vertical hole through a central exhaust hole. The steam-isolating pressure tapping element adopts a reverse Y-shaped double pressure tapping element. The sealing plug is improved, so that when the isolation liquid is replaced, a person can be prevented from being scalded by high-temperature steam, and the sealing plug can be prevented from being blown away by high-speed steam, and the application is safe and reliable. Through the cooperation of the two differential pressure force transmitters with different ranges, the range of inaccurate values in the flowmeter is greatly reduced, the measurement accuracy is improved, and the wide-range flow measurement requirement is met.

Description

Technical Field

[0001] This invention relates to the field of differential pressure measurement technology, specifically to a wide-range differential pressure flow meter and a method for measuring differential pressure flow. Background Technology

[0002] Currently, differential pressure flow meters are widely used in flow measurement to measure differential pressure. A differential pressure flow meter mainly consists of a differential pressure element, measuring pipe sections before and after the element, a pressure tapping device, a differential pressure transmitter, and a flow computer. When measuring steam flow, the pressure tapping device must prevent high-temperature steam from directly contacting the differential pressure transmitter; otherwise, it will damage the transmitter.

[0003] Traditional measurement methods involve installing condensers on the pressure-conducting pipe between the flowmeter's differential pressure component and the differential pressure transmitter. Furthermore, condensers are installed on both sides of the pressure tapping device. High-temperature steam is cooled into condensate in the condenser before the pressure is transmitted to the differential pressure transmitter. This not only directly increases the measurement error of the differential pressure transmitter, but also, because the condensate level in the double-sided pressure-conducting pipes is uncontrollable and unpredictable, a difference in condensate level exists between the two condensers. Even a 1 mm difference in condensate level between the two condensers introduces a 10 Pa measurement error into the differential pressure transmitter, further increasing the measurement error. After winter, to prevent the differential pressure transmitter from overheating, the insulation and heat tracing facilities must be removed, making the operation cumbersome and resulting in poor measurement accuracy.

[0004] Prior art (201820596142.2) discloses a pressure tapping device for a differential pressure flow meter. This device includes an isolation hole group within a valve body seat, connecting the differential pressure conduit interface to the pressure measuring port of the differential pressure transducer. The isolation hole group includes a longitudinally arranged isolation hole communicating with the pressure measuring port, and a pressure guiding hole extending obliquely upwards from the differential pressure conduit interface and communicating with the isolation hole. The isolation hole is filled with an insulating liquid to insulate the high-temperature gas being measured. During measurement, the gas being measured is filled into the pressure guiding hole. Due to the insulating liquid in the isolation hole, the pressure of the gas being measured acts on the differential pressure transmitter through the insulating liquid, providing insulation. The pressure guiding hole is obliquely arranged; when condensation occurs in the pressure guiding hole and the isolation hole, the condensed water flows back through the obliquely arranged pressure guiding hole, preventing condensation and malfunction in the isolation hole, thus reducing the difficulty of pressure tapping in the high-temperature gas pipeline. However, the existing technology has the following problems: when the antifreeze needs to be replaced, the high-temperature steam can easily burn people, and the plug used to seal the isolation hole can easily be blown away by the high-velocity steam and lost or cause injury, posing a safety hazard.

[0005] Furthermore, this pressure tapping device only connects to one differential pressure transmitter. Differential pressure transmitters typically have a measurement range, including a lower limit, minimum accurate value, maximum accurate value, and upper limit. However, measurements between the lower limit and the minimum accurate value are generally inaccurate. Therefore, when measuring smaller flow rates, the differential pressure flow meter exhibits a large range of inaccuracies, failing to meet flow measurement requirements.

[0006] Therefore, it is evident that the existing differential pressure flowmeters still have inconveniences and shortcomings in terms of structure, method, and use, and urgently need further improvement. How to create a new wide-range differential pressure flowmeter and its differential pressure flow measurement method, so that through improvements to the pressure tapping components, can not only effectively avoid injuries from high-temperature steam and meet the safety requirements for mid-flow replacement of the isolation fluid, but also reduce the inaccuracy range within the differential pressure flowmeter's measurement range, improve measurement accuracy, and meet the needs of wide-range flow measurement, has become a pressing goal for the industry. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a wide-range differential pressure flow meter that, through improvements to the pressure tapping components, can not only effectively avoid injury from high-temperature steam and meet the safety requirements for mid-process replacement of the isolation fluid, but also reduce the range of inaccurate values ​​within the range of the differential pressure flow meter, improve measurement accuracy, and meet the wide-range flow measurement requirements, thereby overcoming the shortcomings of existing differential pressure flow meters.

[0008] To solve the above-mentioned technical problems, the present invention provides a differential pressure flow meter, including a differential pressure transmitter and a steam isolation pressure tap connected thereto. The steam isolation pressure tap has a guide hole communicating with a steam guide pipe and a vertical isolation liquid hole intersecting with the guide hole. A sealing plug is provided at the top of the vertical isolation liquid hole. The sealing plug adopts a conical screw structure. The center of the screw part of the conical screw structure has an exhaust hole. The front end of the screw part has a transverse vent hole communicating with the exhaust hole. The upper end of the vertical isolation liquid hole is set as a countersunk hole structure. The conical part of the conical screw structure abuts against the lower edge of the countersunk hole structure to seal the vertical isolation liquid hole. When the conical part of the conical screw structure leaves the lower edge of the countersunk hole structure, the high-temperature steam in the vertical isolation liquid hole enters the exhaust hole through the transverse vent hole and is discharged from the end of the exhaust hole.

[0009] A further improvement is made by making the diameter of the front end of the screw with the lateral vent hole smaller than the diameter of the rear end of the threaded screw.

[0010] In a further improvement, the steam isolation pressure tapping component has an internally threaded zero-adjustment hole at its center that communicates with the guide holes on both sides. A zero-adjustment stopper is installed at the upper end of the zero-adjustment hole, and two separate recessed holes are provided at the bottom of the zero-adjustment hole. The two recessed holes are respectively connected to the guide holes on both sides. The bottom pin rod of the zero-adjustment stopper abuts against or separates from the upper edge of one of the recessed holes, thereby achieving the cut-off or conduction of the guide holes on both sides.

[0011] In a further improvement, the two sinkholes are arranged parallel to each other and downwards, with one sinkhole being a central sinkhole and the other being an eccentric sinkhole.

[0012] In a further improvement, the steam isolation pressure tapping component adopts an inverted Y-shaped dual pressure tapping component. The inverted Y-shaped dual pressure tapping component includes a pressure tapping component body and two lower end connecting parts extending obliquely downward from its lower end to both sides. The pressure tapping component body has two parallel vertical holes for the isolation liquid inside. The lower ends of the two vertical holes fork along with the two lower end connecting parts to form two sets of pressure tapping holes. Each set of pressure tapping holes is connected to a differential pressure transmitter.

[0013] In a further improvement, the two differential pressure transmitters include a small-range differential pressure transmitter and a large-range differential pressure transducer, wherein the minimum accuracy value of the large-range differential pressure transducer is greater than the minimum accuracy value of the small-range differential pressure transmitter and less than the maximum accuracy value of the small-range differential pressure transmitter.

[0014] In a further improvement, both differential pressure transmitters are connected to the flow computer via cables.

[0015] As an improvement of the present invention, the present invention also provides a differential pressure flow measurement method for the above-mentioned differential pressure flow meter, the measurement method including differential pressure rising condition and differential pressure falling condition.

[0016] When the differential pressure is increasing, if the measured value of the small-range differential pressure transmitter is less than the preset increasing switching value, the flow computer selects and outputs the measured value of the small-range differential pressure transmitter; if the measured value of the small-range differential pressure transmitter is greater than or equal to the increasing switching value, the flow computer selects and outputs the measured value of the large-range differential pressure transmitter.

[0017] When the differential pressure decreases, if the measured value of the large-range differential pressure transmitter is greater than the preset decrease switching value, the flow computer selects and outputs the measured value of the large-range differential pressure transmitter; if the measured value of the large-range differential pressure transmitter is less than or equal to the decrease switching value, the flow computer selects and outputs the measured value of the small-range differential pressure transmitter.

[0018] The preset upward switching value and downward switching value are both located between the minimum accurate value of the large-range differential pressure transmitter and the maximum accurate value of the small-range differential pressure transmitter, and the upward switching value and downward switching value are not equal.

[0019] In a further improvement, the descent switching value is determined by subtracting the hysteresis value from the maximum accurate value of the small-range differential pressure transmitter.

[0020] In a further improvement, the hysteresis value is any positive number between the minimum and maximum hysteresis values; the decreasing switching value is any number within an interval determined by the maximum accuracy value, minimum hysteresis value, and maximum hysteresis value of the small-range differential pressure transmitter; and the increasing switching value is any number between the minimum accuracy value of the large-range differential pressure transmitter and the maximum accuracy value of the small-range differential pressure transmitter, excluding the decreasing switching value interval.

[0021] With this design, the present invention has at least the following advantages:

[0022] 1. The differential pressure flow meter of the present invention improves the sealing plug so that when replacing the isolation fluid, the high-temperature steam can first be discharged from the central vent hole of the sealing plug before the sealing plug is removed. This can prevent people from being burned by high-temperature steam and prevent the sealing plug from being blown away by high-velocity steam, making it safe and reliable.

[0023] 2. Furthermore, by improving the two recessed holes of the zero-adjustment hole, it is possible to easily and conveniently cut off and connect the guide holes on both sides, thereby achieving the purpose of zeroing the differential pressure transmitter, and the manufacturing process is simple.

[0024] 3. Furthermore, the inverted Y-shaped dual pressure tapping mechanism enables symmetrical connection between the pressure tapping mechanism and the two differential pressure transducers, improving the rationality and scientific nature of the flowmeter's structural layout. Moreover, by setting the two differential pressure transducers to have different ranges, the crossover and expansion of these two ranges can broaden the measurement range of the differential pressure flowmeter, improve the accuracy range, narrow the inaccuracy range, and meet the needs of wide-range flow measurement.

[0025] 4. Furthermore, by using the range setting of the hysteresis value, the value range of the upward switching value and the downward switching value are effectively defined, ensuring that the upward switching value and the downward switching value are set differently, guaranteeing smooth switching between two differential pressure transmissions with different ranges, and also meeting the customer's requirements for using the hysteresis value. Attached Figure Description

[0026] The above is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] Figure 1 This is a schematic diagram of the structure of the wide-range differential pressure flow meter of the present invention.

[0028] Figure 2 This is a structural schematic diagram of the wide-range differential pressure flow meter of the present invention from another angle.

[0029] Figure 3 This is a schematic diagram of the inverted Y-shaped dual pressure tapping component in the wide-range differential pressure flowmeter of this invention.

[0030] Figure 4 This is a structural schematic diagram of a cross-sectional view of the inverted Y-shaped double pressure tapping component in the wide-range differential pressure flowmeter of the present invention.

[0031] Figure 5 This is a structural schematic diagram of another cross-sectional view of the inverted Y-shaped dual pressure tapping component in the wide-range differential pressure flowmeter of the present invention.

[0032] Figure 6 yes Figure 4 Cross-sectional view along line AA.

[0033] Figure 7 This is a schematic diagram of the sealing plug in the wide-range differential pressure flowmeter of the present invention.

[0034] Figure 8 This is a schematic diagram of the zero-adjustment cut-off element in the wide-range differential pressure flowmeter of the present invention.

[0035] Figure 9 This is a top view of the main body of the pressure tapping component in the wide-range differential pressure flowmeter of the present invention.

[0036] Among them, 1. Flow computer;

[0037] 2. Cable;

[0038] 3. Zeroing stop; 31. Zeroing hole; 32. Countersunk hole; 33. Countersunk hole; 34. Ejector pin;

[0039] 4. Sealing plug; 41. Screw section; 42. Vent hole; 43. Lateral vent; 44. Conical head section;

[0040] 5. Steam isolation pressure tapping component; 51. Pressure tapping component body; 52. Lower end connection part; 53. Lower end connection part; 54. Guide hole; 55. Guide hole; 56. Isolation fluid vertical hole; 57. Isolation fluid vertical hole; 61. Connection port; 62. Connection port; 63. Connection port; 64. Connection port;

[0041] 6. Differential pressure transmitter;

[0042] 7. Differential pressure transmission;

[0043] 8. Cables;

[0044] 9. Steam guide pipe;

[0045] 10. Shut-off valve;

[0046] 12. Mounting bracket;

[0047] 14. Shut-off valve;

[0048] 15. Steam guide pipe;

[0049] 16. Sealing plugs. Detailed Implementation

[0050] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Specific embodiments are as follows.

[0051] Appendix Figure 1 This diagram shows an overall and partial perspective view of the wide-range differential pressure flow meter of this embodiment at one angle. Figure 2 This illustrates another angle (with) the wide-range differential pressure flowmeter of this embodiment. Figure 1 The overall structure is at a 90-degree angle. This embodiment of the wide-range differential pressure flow meter includes a steam isolation pressure tap 5 and two differential pressure transmitters connected to it, namely, a differential pressure transmitter 6 and a differential pressure transducer 7. The side of the steam isolation pressure tap 5 is also connected to the differential pressure component of the pipeline to be measured via steam guide pipes 9 and 15. Shut-off valves 10 and 14 are provided on the steam guide pipes 9 and 15. The steam isolation pressure tap 5 is also fixed to the upper part of the pipeline to be measured via a mounting bracket 12.

[0052] In this embodiment, the steam isolation pressure tap 5 is an inverted Y-shaped double pressure tap. (See attached...) Figure 3 As shown, the inverted Y-shaped dual pressure tapping component includes a pressure tapping body 51 and two lower end connecting parts 52 and 53 extending obliquely downward from its lower end to both sides. The two lower end connecting parts 52 and 53 are respectively used to connect the differential pressure transmitter 6 and the differential pressure gearbox 7.

[0053] Please refer to the appendix. Figure 4 and 5 As shown, in this embodiment, the steam isolation pressure tapping component 5 is provided with guide holes 54 and 55 communicating with the steam guide pipes 9 and 15, and isolation liquid vertical holes 56 and 57 intersecting with the guide holes 54 and 55. For example, the upper end of the steam guide pipe 9 is connected to the upwardly inclined guide hole 54, and the guide hole 54 intersects with the isolation liquid vertical hole 56 at the connection port 61. The upper end of the steam guide pipe 15 is connected to the upwardly inclined guide hole 55, and the guide hole 55 intersects with the isolation liquid vertical hole 57 at the connection port 62.

[0054] Two vertical isolation fluid holes 56 and 57 are arranged in parallel, and sealing plugs 4 and 16 are provided at the top of the vertical isolation fluid holes 56 and 57. The lower ends of the vertical isolation fluid holes 56 and 57 are branched off from the two lower end connecting parts 52 and 53, forming two sets of pressure taps, each set of pressure taps connected to a differential pressure transmitter. Isolation fluid is added to the vertical isolation fluid holes 56 and 57 from their tops. When the isolation fluid reaches the connecting ports 61 and 62, it overflows from the downwardly angled guide holes 54 and 55, stopping the addition of isolation fluid. When measuring differential pressure, the pressure of the high-temperature steam being measured acts on the differential pressure transmitters 6 and 7 through the isolation fluid, and the differential pressure values ​​are measured by both differential pressure transmitters 6 and 7.

[0055] Both differential pressure transmitters are connected to the flow computer 1 via cables. (See attached...) Figure 1 In the middle, differential pressure transmitter 6 is connected to flow computer 1 via cable 2; differential pressure transmitter 7 is connected to flow computer 1 via cable 8.

[0056] See attached document Figures 5 to 7 As shown, in this embodiment, the sealing plug 4 adopts a conical screw structure. The screw portion 41 of the conical screw structure has a vent hole 42 at its center, and a transverse vent hole 43 communicating with the vent hole 42 at its front end. The upper end of the vertical hole 56 of the isolation fluid is configured as a countersunk hole structure. The conical portion 44 of the conical screw structure abuts against the lower edge of the countersunk hole structure, thus sealing the vertical hole 56 of the isolation fluid. When the conical portion 44 of the conical screw structure leaves the lower edge of the countersunk hole structure, the high-temperature vapor in the vertical hole 56 of the isolation fluid enters the vent hole 42 through the transverse vent hole 43 and is discharged from the end of the vent hole 42. The sealing plug 16 has the same structure as the sealing plug 4. It should be noted that the isolation fluid in this application can be an antifreeze isolation fluid, used in cold winter weather, to meet the requirements for accurate measurement of differential pressure in cold weather, solving the adverse effects of temperature changes on measurement.

[0057] Preferably, the diameter of the front end of the screw with the transverse vent 43 is smaller than the diameter of the rear end of the threaded screw. This facilitates the entry of high-temperature steam into the transverse vent 43 and its discharge through the exhaust port 42, preventing it from being discharged from the threaded part of the screw. The threaded connection also effectively prevents the sealing plug from being blown away by the high-temperature steam, thus improving safety.

[0058] Please refer to the appendix. Figure 4 , 5As shown in Figures 8 and 9, the steam isolation pressure tapping component 5 has an internally threaded zero-adjustment hole 31 at its center, which communicates with the guide holes 54 and 55 on both sides. A zero-adjustment cut-off component 3 is installed at the upper end of the zero-adjustment hole 31. The bottom of the zero-adjustment hole 31 has two separate recessed holes 32 and 33, which communicate with the guide holes 54 and 55 on both sides respectively. For example, the recessed hole 32 communicates with the guide hole 54 at the connection port 63, and the recessed hole 33 communicates with the guide hole 55 at the connection port 64. The conical surface of the bottom pin rod 34 of the zero-adjustment cut-off component 3 abuts against the upper edge of one of the recessed holes 32, thus cutting off the guide holes 54 and 55 on both sides. When the conical surface of the bottom ejector pin 34 of the zero-adjustment cutoff component 3 separates from the upper edge of the recessed hole 32, the steam in the guide holes 54 and 55 on both sides will communicate at the bottom of the zero-adjustment hole 31, thus achieving the conduction of the two guide holes 54 and 55 and realizing the zero-adjustment purpose of the two differential pressure transmissions 6 and 7. Of course, the bottom ejector pin 34 of the zero-adjustment cutoff component 3 can also abut or separate from the upper edge of the recessed hole 33 to achieve the cutoff or conduction of the guide holes 54 and 55 on both sides.

[0059] Preferably, the two countersunk holes 32 and 33 are arranged parallel to each other downwards, with one countersunk hole 32 being a central countersunk hole and the other countersunk hole 33 being an eccentric countersunk hole, which facilitates processing and manufacturing.

[0060] To improve the accuracy of differential pressure measurement, in this embodiment, the two differential pressure transmitters 6 and 7 employ two different ranges: a small-range differential pressure transmitter 6 and a large-range differential pressure transmitter 7. The minimum accuracy value of the large-range differential pressure transmitter 7 is significantly greater than the minimum accuracy value of the small-range differential pressure transmitter 6, but less than the maximum accuracy value of the small-range differential pressure transmitter 6. This effectively expands the accuracy range of the large-range differential pressure transmitter 7 for measuring smaller differential pressure values ​​by adding the small-range differential pressure transmitter 6.

[0061] To further ensure the control accuracy and smooth switching logic of the two differential pressure transmitters with different ranges during measurement, the flow computer in this embodiment is configured with rising and falling switching values ​​for selecting between the small-range differential pressure transmitter 6 and the large-range differential pressure transmitter 7. The preset rising and falling switching values ​​are both located between the minimum accurate value of the large-range differential pressure transmitter 7 and the maximum accurate value of the small-range differential pressure transmitter 6, and the rising and falling switching values ​​must be different.

[0062] The descent switching value is determined by subtracting the hysteresis value from the maximum accurate value of the small-range differential pressure transmitter 6.

[0063] To meet user requirements regarding the hysteresis value, a range is set for the hysteresis value. When the hysteresis value is within a range, it can be any positive number between the minimum and maximum hysteresis value. In specific applications, the user determines the value based on actual circumstances to meet their requirements.

[0064] When the hysteresis value is a range, the descent switching value is also a range, that is:

[0065] Maximum descent switching value = Maximum accuracy of the small-range differential pressure transmitter - Minimum operating hysteresis value

[0066] The descent switching value can be any number between the maximum and minimum descent switching values. Furthermore, the ascending switching value is any number between the minimum accurate value of the large-range differential pressure transmitter and the maximum accurate value of the small-range differential pressure transmitter, excluding the descent switching value interval. Since the hysteresis value is positive (non-zero), the ascending switching value may be greater than or less than the descent switching value.

[0067] Before measuring with the aforementioned differential pressure flowmeter: First, zero the small-range differential pressure transmitter 6 and the large-range differential pressure transmitter 7. Then, remove the sealing plugs 4 and 16, and inject isolation liquid into the vertical holes 56 and 57 until the isolation liquid reaches the connection ports 61 and 62. Install the sealing plugs 4 and 16 to seal the top of the vertical holes 56 and 57. Next, shut off the shut-off valves 10 and 14, and then loosen the pin rod 34 in the zeroing shut-off component 3 to connect the steam guide pipe 9 and the steam guide pipe 15. Then, tighten the pin rod 34 in the zeroing shut-off component 3 to shut off the guide hole 54 and the guide hole 55. Finally, open the shut-off valves 10 and 14, and begin measuring the differential pressure value using the small-range differential pressure transmitter 6 and the large-range differential pressure transmitter 7.

[0068] The measurement process includes both differential pressure increase and differential pressure decrease conditions.

[0069] During the differential pressure rise process, if the measured value of the small-range differential pressure transmitter 6 is less than the preset rise switching value, the flow computer 1 selects and outputs the measured value of the small-range differential pressure transmitter 6; if the measured value of the small-range differential pressure transmitter 6 is greater than or equal to the rise switching value, the flow computer 1 selects and outputs the measured value of the large-range differential pressure transmitter 7.

[0070] When the differential pressure decreases, if the measured value of the large-range differential pressure transmitter 7 is greater than the preset decrease switching value, the flow computer 1 selects and outputs the measured value of the large-range differential pressure transmitter 7. If the measured value of the large-range differential pressure transmitter 7 is less than or equal to the decrease switching value, the flow computer 1 selects and outputs the measured value of the small-range differential pressure transmitter 6.

[0071] When the flow meter needs to be replaced after a period of use, first shut off the shut-off valves 10 and 14, then loosen the sealing plugs 4 and 16 a short distance to allow the high-temperature steam in the steam guide pipe 9 and guide hole 54, and the steam guide pipe 15 and guide hole 55 to be discharged through the exhaust holes. Then remove the sealing plugs 4 and 16 and drain the old isolation fluid from the drain ports at the bottom of the small-range differential pressure transmitter 6 and the large-range differential pressure transmitter 7. Then add new isolation fluid from the top of the vertical holes 56 and 57, install the sealing plugs 4 and 16, and tighten them to complete the replacement of the isolation fluid. It is simple and convenient.

[0072] This differential pressure flow measurement method reduces the range of inaccurate values ​​within the range of a single flow meter, improves the measurement accuracy of the flow meter, and ensures the control precision and switching logic of the two differential pressure transmissions during measurement, resulting in smooth operation and accurate measurement.

[0073] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0074] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0075] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, or alterations made by those skilled in the art using the disclosed technical content shall fall within the protection scope of the present invention.

Claims

1. A wide-range differential pressure flow meter, comprising a differential pressure transmitter and a steam isolation pressure tap connected thereto, wherein the steam isolation pressure tap has a guide hole communicating with a steam guide pipe and a vertical isolation liquid hole intersecting the guide hole, and a sealing plug is provided at the top of the vertical isolation liquid hole, characterized in that, The sealing plug adopts a conical screw structure. The screw part of the conical screw structure has a vent hole at its center and a transverse vent hole at its front end that communicates with the vent hole. The upper end of the vertical hole of the isolation liquid is set as a countersunk hole structure. The conical part of the conical screw structure abuts against the lower edge of the countersunk hole structure to seal the vertical hole of the isolation liquid. When the conical part of the conical screw structure leaves the lower edge of the countersunk hole structure, the high-temperature vapor in the vertical hole of the isolation liquid enters the vent hole through the transverse vent hole and is discharged from the end of the vent hole. The diameter of the front end of the screw with the lateral vent is smaller than the diameter of the rear end of the threaded screw; The steam isolation pressure tapping component has an internally threaded zero-adjustment hole at its center that communicates with the guide holes on both sides. A zero-adjustment stop component is installed at the upper end of the zero-adjustment hole. The bottom of the zero-adjustment hole has two separate recessed holes. The two recessed holes are respectively connected to the guide holes on both sides. The bottom pin rod of the zero-adjustment stop component abuts or separates from the upper edge of one of the recessed holes, thereby achieving the cut-off or conduction of the guide holes on both sides.

2. The differential pressure flow meter according to claim 1, characterized in that, The two sinkholes are arranged parallel to each other downwards, one of which is a central sinkhole and the other is an eccentric sinkhole.

3. The differential pressure flow meter according to claim 1 or 2, characterized in that, The steam isolation pressure tapping component adopts an inverted Y-shaped dual pressure tapping component. The inverted Y-shaped dual pressure tapping component includes a pressure tapping component body and two lower end connecting parts extending obliquely downward from its lower end to both sides. The pressure tapping component body has two parallel vertical holes for the isolation liquid inside. The lower ends of the two vertical holes fork with the two lower end connecting parts to form two sets of pressure tapping holes. Each set of pressure tapping holes is connected to a differential pressure transmitter.

4. The differential pressure flow meter according to claim 3, characterized in that, The two differential pressure transmitters include a small-range differential pressure transmitter and a large-range differential pressure transmitter, wherein the minimum accuracy value of the large-range differential pressure transmitter is greater than the minimum accuracy value of the small-range differential pressure transmitter and less than the maximum accuracy value of the small-range differential pressure transmitter.

5. The differential pressure flow meter according to claim 4, characterized in that, Both differential pressure transmitters are connected to the flow computer via cables.

6. The differential pressure flow rate measurement method of the differential pressure flow meter according to claim 5, characterized in that, The measurement method includes differential pressure rising conditions and differential pressure falling conditions; When the differential pressure is increasing, if the measured value of the small-range differential pressure transmitter is less than the preset increasing switching value, the flow computer selects and outputs the measured value of the small-range differential pressure transmitter; if the measured value of the small-range differential pressure transmitter is greater than or equal to the increasing switching value, the flow computer selects and outputs the measured value of the large-range differential pressure transmitter. When the differential pressure decreases, if the measured value of the large-range differential pressure transmitter is greater than the preset decrease switching value, the flow computer selects and outputs the measured value of the large-range differential pressure transmitter; if the measured value of the large-range differential pressure transmitter is less than or equal to the decrease switching value, the flow computer selects and outputs the measured value of the small-range differential pressure transmitter. The preset upward switching value and downward switching value are both located between the minimum accurate value of the large-range differential pressure transmitter and the maximum accurate value of the small-range differential pressure transmitter, and the upward switching value and downward switching value are not equal.

7. The differential pressure flow measurement method of the differential pressure flow meter according to claim 6, characterized in that, The descent switching value is determined by subtracting the hysteresis value from the maximum accurate value of the small-range differential pressure transmitter.

8. The differential pressure flow rate measurement method of the differential pressure flow meter according to claim 7, characterized in that, The hysteresis value is any positive number between the minimum and maximum hysteresis values. The descent switching value is any number within the range determined by the maximum accuracy, minimum hysteresis, and maximum hysteresis values ​​of the small-range differential pressure transmitter. The ascending switching value is any number between the minimum accuracy of the large-range differential pressure transmitter and the maximum accuracy of the small-range differential pressure transmitter, excluding the descent switching value range.

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