Condensation-aiding and anti-freezing device for pressure guide pipe during steam measurement of orifice plate flowmeter

Abstract

The utility model discloses a pressure guide pipe coagulation-aiding anti-freezing device during steam measurement of an orifice plate flowmeter, a compressed air tracing pipe is attached to the outside of each pressure guide pipe, a compressed air inlet mechanism is arranged at the air inlet end of each compressed air tracing pipe, and a compressed air recovery mechanism is arranged at the air outlet end of each compressed air tracing pipe. A compressed air heating pipe of the compressed air introduction mechanism is communicated with the compressed air tracing pipe, a steam jacket is arranged outside the compressed air heating pipe, and a steam supply mechanism is arranged on the steam jacket. According to the utility model, steam introduction is stopped in summer, and cooling compressed air is introduced into the compressed air heating pipe, so that the compressed air cools the orifice plate flowmeter pressure guide pipe and the condenser through the compressed air tracing pipe; in winter, the steam jacket heats compressed air in the compressed air heating pipe, so that a pressure guide pipe, a condenser and a transmitter diaphragm capsule of the orifice plate flowmeter are prevented from being frozen, and accurate measurement of the orifice plate flowmeter is guaranteed.

Description

Technical Field

[0001] This utility model belongs to the field of orifice plate flowmeter detection technology, specifically relating to a pressure guide tube anti-condensation and antifreeze device for steam measurement using an orifice plate flowmeter. Background Technology

[0002] An orifice plate flow meter is a differential pressure flow meter suitable for pipes with nominal diameters between 15mm and 1200mm. It consists of a standard orifice plate and a multi-parameter differential pressure transmitter, and is used to measure the flow rate of gas, steam, and liquid. This type of flow meter features simple structure, convenient maintenance, stable performance, and reliable use. The working principle of the orifice plate flow meter is to utilize the static pressure energy formed when the fluid passes through the orifice plate to convert into kinetic energy, thereby generating a pressure difference. By measuring this pressure difference, the velocity and flow rate of the fluid are determined, and then converted into a 4mA-20mA DC current signal and output to the DCS for convenient real-time monitoring by process control operators. Traditional orifice plate flowmeters are widely used and have good detection results. However, when detecting flow in steam pipelines, in summer, the high temperature can cause poor condensation in the condenser, resulting in steam inside the condenser. This makes it impossible for the liquid levels on the positive and negative pressure sides of the condenser to be consistent, leading to inaccurate flowmeter measurements. In winter, the lowest temperature in northern regions can reach around -30°C, causing the pressure-conducting pipes, condenser, and transmitter diaphragm of the orifice plate flowmeter to freeze, expand, and be damaged, resulting in no flowmeter reading. In both cases, the process cannot calculate the steam output or usage.

[0003] To overcome the above shortcomings, the existing solution is to fill the condenser with water in summer and wrap electric or welded steam tracing pipes around the pressure-conducting pipe, condenser pipe, and transmitter of the orifice flowmeter in winter. This is not only labor-intensive and wasteful of manpower and resources, but also ineffective. In summer, shortly after filling the condenser with water, steam from the steam pipeline will enter the condenser along with the pressure-conducting pipe, causing the condenser to return to a state of poor condensation. In winter, the wrapped electric tracing pipe will be damaged by the steam flowing into the base of the pressure-conducting pipe, causing it to short-circuit and the tracing function to fail. This will still damage the pressure-conducting pipe, transmitter diaphragm, and condenser. If the condenser freezes and cracks, and steam tracing is used, the condensate in the pressure-conducting pipe and condenser tube will evaporate due to the excessively high temperature of the tracing pipe. This will not only lead to inaccurate measurements but also damage the instruments because the overheated steam in the steam pipeline will enter them. This will cause the orifice plate flow meter to frequently malfunction or be damaged. At best, it will be impossible to calculate the steam output and consumption; at worst, it will cause process disorder and increase the company's operating costs. In summer, there is a risk of burns to instrument maintenance workers during the condenser tube water injection process or when using steam tracing in winter. In the event of short circuit due to burns to the electric tracing, there is a risk of electric shock to instrument maintenance workers. Utility Model Content

[0004] The purpose of this invention is to provide a device for preventing freezing and condensation of the pressure guide tube when measuring steam with an orifice plate flowmeter, so as to solve the above-mentioned problems.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0006] A pressure-guided condensation and antifreeze device for steam measurement using an orifice plate flowmeter includes a steam pipeline and an orifice plate throttling element disposed between the steam pipelines. On the positive pressure side of the orifice plate throttling element, a positive pressure-guided pipe I, a positive pressure-guided condenser, and a positive pressure-guided pipe II are sequentially arranged. On the negative pressure side of the orifice plate throttling element, a negative pressure-guided pipe I, a negative pressure-guided condenser, and a negative pressure-guided pipe II are sequentially arranged. The positive pressure-guided pipe II and the negative pressure-guided pipe II are respectively connected to the positive and negative pressure sides of the diaphragm box of a differential pressure transmitter. The positive pressure-guided pipe I, the positive pressure-guided condenser, the positive pressure-guided pipe II, and the negative pressure-guided pipe... I. A compressed air heat tracing pipe is attached to the outside of the negative pressure side condenser and the negative pressure side pressure guide pipe II. A compressed air inlet mechanism is provided at the air inlet end of the compressed air heat tracing pipe, and a compressed air recovery mechanism is provided at the exhaust end of the compressed air heat tracing pipe. The compressed air inlet mechanism is sequentially connected to a compressed air main pipe, a compressed air pipe, and a compressed air heating pipe along the air flow direction. The compressed air heating pipe is connected to the compressed air heat tracing pipe. A heating mechanism is provided on the compressed air heating pipe. The heating mechanism includes a steam jacket sleeved outside the compressed air heating pipe. A steam supply mechanism is provided on the steam jacket.

[0007] To further realize this utility model, the differential pressure transmitter is electrically connected to the DCS.

[0008] To further realize this utility model, a shut-off valve I, a compressed air regulating valve and a shut-off valve II are sequentially arranged on the compressed air pipe along the air flow direction. The shut-off valve I, the compressed air regulating valve and the shut-off valve II are electrically connected to the DCS.

[0009] To further realize this utility model, the steam supply mechanism includes a low-pressure steam supply distribution platform and a steam supply pipe. The steam supply pipe is connected to the inlet end of the steam jacket. A shut-off valve III, a steam regulating valve and a shut-off valve IV are sequentially arranged on the steam supply pipe along the steam flow direction. The shut-off valve III, the steam regulating valve and the shut-off valve IV are electrically connected to the DCS respectively.

[0010] To further realize this utility model, a drainage mechanism is provided on the steam jacket, and the drainage mechanism is provided with a steam condensate pipe and a low-pressure steam condensate distribution platform in sequence along the water flow direction.

[0011] To further realize this utility model, the compressed air recovery mechanism includes a compressed air recovery pipe, and an air compressor inlet buffer tank and an air compressor are installed at the outlet end of the compressed air recovery pipe. The compressed air recovery pipe is connected to the air compressor inlet buffer tank and finally enters the air compressor, which can realize the benefit of recycling pure compressed air and save costs.

[0012] To further realize this utility model, a thermal resistor is installed at the air inlet end of the compressed air heating pipe, and the thermal resistor is electrically connected to the DCS. Connecting the thermal resistor signal to the DCS system allows personnel and instrument maintenance workers to easily observe the real-time temperature of the compressed air. Especially in winter, the temperature of the steam regulating valve and the thermal resistor can be controlled through the DCS system program to set the opening of the steam regulating valve, thereby achieving the function of maintaining a constant temperature of the compressed air inside the compressed air heating pipe.

[0013] To further realize this utility model, a filter and pressure reducing valve is provided at the air inlet end of the compressed air pipe. The filter and pressure reducing valve can filter out trace impurities and moisture in the compressed air, and can also regulate the compressed air pressure.

[0014] The advantages of this utility model compared to the prior art are as follows:

[0015] The purpose of this invention is to provide a device for condensation-aiding and antifreeze treatment of the pressure guide tube when measuring steam with an orifice plate flowmeter. It is simple to install and operate, reliable in use, and easy to maintain. In summer, steam supply is stopped, and cooled compressed air is directly circulated in the compressed air heating pipe. Specifically, shut-off valve III, steam regulating valve, and shut-off valve IV are closed, while shut-off valve I, compressed air regulating valve, and shut-off valve II are opened. This allows compressed air to pass through the compressed air heating pipe and reach the orifice plate flowmeter pressure guide tube and condenser for cooling, causing water to accumulate in the condenser and pressure guide tube. This achieves a consistent liquid level in the positive and negative pressure sides of the condenser and pressure guide tube, thus aiding condensation in the orifice plate flowmeter pressure guide tube and condenser. In winter, only shut-off valve I, compressed air regulating valve, shut-off valve II, shut-off valve III, and steam regulating valve need to be opened. The shut-off valve IV and the steam jacket heat the compressed air in the compressed air heating pipe. The heated compressed air then passes through the compressed air heat tracing pipe to prevent freezing of the orifice plate flowmeter pressure guide pipe, condenser, and transmitter diaphragm. By controlling the opening of the steam regulating valve, the heat tracing temperature is kept constant at around 15℃. This prevents the condenser from becoming ineffective due to excessive temperature and also prevents ice formation in the pressure guide pipe, condenser, and differential pressure transmitter diaphragm. This ensures accurate measurement by the orifice plate flowmeter, enabling process personnel to accurately calculate steam usage and output, and settle costs or benefits. This guarantees the accuracy of steam usage and output accounts for the entire company, reduces the damage rate of steam medium instruments, saves company operating costs, and avoids the risk of burns and electric shocks to instrument maintenance workers. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of this utility model;

[0017] The meanings of the reference numerals in the attached diagram are as follows: 1. Positive pressure side pressure guide pipe I; 2. Positive pressure side condenser; 3. Positive pressure side pressure guide pipe II; 4. Negative pressure side pressure guide pipe I; 5. Negative pressure side condenser; 6. Negative pressure side pressure guide pipe II; 7. Compressed air heat tracing pipe; 8. Compressed air main pipe; 9. Compressed air pipe; 10. Compressed air heating pipe; 11. Steam jacket; 12. Differential pressure transmitter; 13. Shut-off valve I; 14. Compressed air regulating valve; 15. Shut-off valve II; 16. Low-pressure steam supply distribution panel; 17. Steam supply pipe; 18. Shut-off valve III; 19. Steam regulating valve; 20. Shut-off valve IV; 21. Steam condensate pipe; 22. Low-pressure steam condensate distribution panel; 23. Compressed air recovery pipe; 24. Air compressor inlet buffer tank; 25. Air compressor; 26. Resistance temperature detector (RTD); 27. Filter pressure reducing valve; 28. Steam pipeline; 29. ​​Orifice plate throttling element; 30. Diaphragm box; 31. DCS. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0019] like Figure 1As shown, a pressure-guided condensation and antifreeze device for steam measurement using an orifice plate flowmeter includes a steam pipeline 28 and an orifice plate throttling element 29 disposed between the steam pipelines 28. On the positive pressure side of the orifice plate throttling element 29, a positive pressure-guided pipe I1, a positive pressure-guided condenser 2, and a positive pressure-guided pipe II3 are sequentially arranged. On the negative pressure side of the orifice plate throttling element 29, a negative pressure-guided pipe I3, a negative pressure-guided condenser 5, and a negative pressure-guided pipe II6 are sequentially arranged. The positive pressure-guided pipe II3 and the negative pressure-guided pipe II6 are respectively connected to the positive and negative pressure sides of the diaphragm box 30 of a differential pressure transmitter 12. The differential pressure transmitter 12 is connected to a DCS. 31. Electrical connection: A compressed air heat tracing pipe 7 is installed in close contact with the outside of the positive pressure side pressure guide pipe I1, positive pressure side condenser 2, positive pressure side pressure guide pipe II3, negative pressure side pressure guide pipe I4, negative pressure side condenser 5, and negative pressure side pressure guide pipe II6. A thermal resistor 26 is installed at the air inlet end of the compressed air heat tracing pipe 7. The thermal resistor 26 is connected to the DCS. 31. Electrical connection: The inlet end of the compressed air heating pipe 7 is equipped with a compressed air inlet mechanism, and the outlet end of the compressed air heating pipe 7 is equipped with a compressed air recovery mechanism. The compressed air recovery mechanism includes a compressed air recovery pipe 23, and the outlet end of the compressed air recovery pipe 23 is equipped with an air compressor inlet buffer tank 24 and an air compressor 25. The compressed air inlet mechanism is sequentially connected to a main compressed air pipe 8, a compressed air pipe 9, and a compressed air heating pipe 10 along the air flow direction. A filter pressure reducing valve 27, a shut-off valve I 13, a compressed air regulating valve 14, and a shut-off valve II 15 are sequentially installed on the compressed air pipe 9 along the air flow direction. The shut-off valve I 13, the compressed air regulating valve 14, and the shut-off valve II 15 are respectively connected to the DCS. 31 Electrical connection, the compressed air heating pipe 10 is connected to the compressed air heat tracing pipe 7, the compressed air heating pipe 10 is provided with a heating mechanism, the heating mechanism includes a steam jacket 11 sleeved outside the compressed air heating pipe 10, the steam jacket 11 is provided with a steam supply mechanism, the steam supply mechanism includes a low-pressure steam supply distribution platform 16 and a steam supply pipe 17, the steam supply pipe 17 is connected to the air inlet end of the steam jacket 11, the steam supply pipe 17 is provided with a shut-off valve III 18, a steam regulating valve 19 and a shut-off valve IV 20 in sequence along the steam flow direction, the shut-off valve III 18, the steam regulating valve 19 and the shut-off valve IV 20 are respectively electrically connected to DCS 31, the steam jacket 11 is provided with a drainage mechanism, the drainage mechanism is provided with a steam drain pipe 21 and a low-pressure steam drain distribution platform 22 in sequence along the water flow direction.

Claims

1. A freeze protection device for a vent tube of a flow meter measuring steam, comprising a steam line and a orifice restriction element disposed between the steam line, the orifice restriction element having a positive pressure side and a negative pressure side, the positive pressure side of the orifice restriction element having a positive pressure side vent tube I, a positive pressure side condenser and a positive pressure side vent tube II disposed in series, the negative pressure side of the orifice restriction element having a negative pressure side vent tube I, a negative pressure side condenser and a negative pressure side vent tube II disposed in series, the positive pressure side vent tube II and the negative pressure side vent tube II being connected to the positive pressure side and the negative pressure side of a diaphragm chamber of a differential pressure transmitter, respectively, characterized in that: The positive pressure side pressure guide pipe I (1), the positive pressure side condenser (2), the positive pressure side pressure guide pipe II (3), the negative pressure side pressure guide pipe I (4), the negative pressure side condenser (5) and the negative pressure side pressure guide pipe II (6) are externally attached with a compressed air heat tracing pipe (7), the air inlet end of the compressed air heat tracing pipe (7) is provided with a compressed air inlet mechanism, the air outlet end of the compressed air heat tracing pipe (7) is provided with a compressed air recovery mechanism, the compressed air inlet mechanism is sequentially provided with a compressed air main pipe (8), a compressed air pipe (9) and a compressed air heating pipe (10) in communication along the air flow direction, the compressed air heating pipe (10) is in communication with the compressed air heat tracing pipe (7), and the compressed air heating pipe (10) is provided with a heating mechanism, and the heating mechanism comprises a steam jacket (11) sleeved outside the compressed air heating pipe (10), and the steam jacket (11) is provided with a steam supply mechanism.

2. The freeze protection apparatus for a draft tube of a flow cell flow meter measuring vapor according to claim 1, wherein: The differential pressure transmitter (12) is electrically connected with the DCS (31).

3. An orifice plate flowmeter with freeze protection for the draft tube when measuring steam as claimed in claim 1 or 2, characterized in that: The compressed air pipe (9) is sequentially provided with a stop valve I (13), a compressed air regulating valve (14) and a stop valve II (15) along the air flow direction, and the stop valve I (13), the compressed air regulating valve (14) and the stop valve II (15) are electrically connected with the DCS (31) respectively.

4. The freeze protection apparatus for a well tube of a flow cell flow meter measuring vapor as set forth in Claim 3 wherein: The steam supply mechanism comprises a low-pressure steam supply distribution table (16) and a steam supply pipe (17), the steam supply pipe (17) is in communication with the air inlet end of the steam jacket (11), the steam supply pipe (17) is sequentially provided with a stop valve III (18), a steam regulating valve (19) and a stop valve IV (20) along the steam flow direction, and the stop valve III (18), the steam regulating valve (19) and the stop valve IV (20) are electrically connected with the DCS (31) respectively.

5. The freeze protection apparatus for a draft tube of a flow cell flow meter measuring vapor according to claim 4, wherein: The steam jacket (11) is provided with a drainage mechanism, and the drainage mechanism is sequentially provided with a steam drain pipe (21) and a low-pressure steam drain distribution table (22) along the water flow direction.

6. The freeze protection apparatus for a draft tube of a flow cell flow meter measuring vapor according to claim 5, wherein: The compressed air recovery mechanism comprises a compressed air recovery pipe (23), and the outlet end of the compressed air recovery pipe (23) is provided with an air compressor air inlet buffer tank (24) and an air compressor (25).

7. The freeze protection apparatus for a draft tube of a flow cell flow meter measuring vapor according to claim 6, wherein: The air inlet end of the compressed air heat tracing pipe (7) is provided with a heating resistor (26), and the heating resistor (26) is electrically connected with the DCS (31).

8. The freeze protection apparatus for a conductance cell of a flow cell flow meter as defined in claim 7 wherein: The air inlet end of the compressed air pipe (9) is provided with a filter pressure reducing valve (27).

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