Automatic blowdown device for liquid differential pressure flowmeter

Abstract

The utility model relates to a differential pressure flowmeter, disclose a kind of liquid differential pressure flowmeter automatic blowdown device, including sampling tube and the differential pressure flowmeter of installation on sampling tube, sampling tube is equipped with a pair of exhaust pipe, a pair of exhaust pipe opposite at the both sides of differential pressure flowmeter, a pair of exhaust valve is oppositely equipped on a pair of exhaust pipe;A pair of exhaust pipe is also oppositely equipped with a pair of gas collector, and gas collector is located the upstream of exhaust valve.This device is equipped with exhaust pipe, exhaust valve, gas collector, realizes automatic exhaust blowdown, can avoid personnel scald by high-temperature liquid, reduce personnel operation risk, can also reduce personnel workload, improve work efficiency.

Description

Technical Field

[0001] This utility model relates to the field of differential pressure flow meter technology, specifically to an automatic sewage discharge device for a liquid differential pressure flow meter. Background Technology

[0002] A differential pressure flow meter is an instrument that measures flow rate based on the pressure difference generated during fluid flow. It typically consists of a throttling device, a measuring pipeline, and a differential pressure transmitter. When fluid flows through the throttling device in a pipe, the flow velocity increases due to the reduced flow cross-section. According to Bernoulli's theorem, this increase in kinetic energy leads to a decrease in static pressure, thus creating a pressure difference before and after the throttling device. This pressure difference has a functional relationship with the flow rate; the flow rate can be calculated by measuring the pressure difference. The installation of a differential pressure flow meter is as follows... Figure 1 As shown.

[0003] Flow measurement is of great importance in thermal power plants. Some key flow measurement points are directly related to the safe and stable operation of the unit. In automatic control systems, the accuracy of flow measurement points also affects the quality of regulation, thereby affecting the economic operation of the unit.

[0004] Differential pressure flowmeters are prone to air bubbles in their measuring lines. When excessive gas in the measuring line causes inaccurate readings, manual drain valve opening is often required, increasing workload. Furthermore, the internal liquid temperature is often high, posing a risk of burns during draining. The main causes of air bubbles in the measuring line are: 1) Release of dissolved gases: Gases dissolved in the liquid under high pressure will release as bubbles when pressure decreases (e.g., when passing through a throttling device); 2) Incomplete air removal during liquid injection, leading to residual gas accumulation in the liquid flow; 3) Changes in process conditions (e.g., temperature and pressure changes); 4) Equipment installation: Uneven or tilted installation of the differential pressure flowmeter's measuring line can cause gas to become embedded and form bubbles; 5) Inadequate pump shaft seals and valve seals can allow air to be drawn into the line. Therefore, it is necessary to take measures to eliminate air bubbles and ensure measurement accuracy. Utility Model Content

[0005] The purpose of this invention is to provide an automatic sewage discharge device for a liquid differential pressure flow meter, which collects and automatically discharges the gas in the measuring pipeline, reducing the workload of personnel and eliminating the risk of burns caused by high-temperature media when personnel manually discharge sewage.

[0006] To achieve the above objectives, the present invention adopts the following technical solution.

[0007] An automatic sewage discharge device for a liquid differential pressure flow meter includes a sampling tube and a differential pressure flow meter installed on the sampling tube. The sampling tube is provided with a pair of exhaust pipes, which are located opposite each other on both sides of the differential pressure flow meter. Exhaust valves are provided opposite each other on the pair of exhaust pipes.

[0008] Preferably, the exhaust valve is an electromagnetic exhaust valve.

[0009] Preferably, the electromagnetic exhaust valve is a timed electromagnetic exhaust valve.

[0010] Preferably, the pair of exhaust pipes are connected to the sampling pipe via a three-way valve.

[0011] Preferably, the pair of exhaust pipes are also provided with air collectors opposite each other, and the air collectors are located upstream of the exhaust valve.

[0012] Preferably, both ends of the sampling tube are connected to a throttling device provided on the liquid pipeline.

[0013] Preferably, the sampling tube is also provided with a pair of primary valves near the throttling device, and the pair of primary valves are located on opposite sides of the differential pressure flow meter.

[0014] Preferably, a pair of secondary valves are also provided on the sampling tube near the differential pressure flow meter, and the pair of secondary valves are located on opposite sides of the differential pressure flow meter.

[0015] Preferably, the sampling tube is equipped with a balancing valve connected in parallel with the differential pressure flow meter.

[0016] Compared with the prior art, this utility model has the following advantages:

[0017] 1) Achieve automatic exhaust and sewage discharge; 2) Reduce workload and improve work efficiency; 3) Reduce operational risks for personnel. Attached Figure Description

[0018] The features and advantages of this utility model can be more clearly understood by referring to the accompanying drawings. The drawings are schematic and should not be construed as limiting the utility model in any way. In the drawings:

[0019] Figure 1 A schematic diagram of the installation of a prior art differential pressure flow meter is shown.

[0020] Figure 2 A schematic diagram of the installation of the liquid differential pressure flowmeter sewage discharge device of this utility model is shown.

[0021] Figure 3 A partial schematic diagram of the sewage discharge device of the liquid differential pressure flow meter of this utility model is shown.

[0022] Wherein: 1-Throttling device; 2-Pipeline; 3-Positive pressure side sampling pipe; 4-Positive pressure side primary valve; 5-Positive pressure side secondary valve; 6-Positive pressure side drain valve; 7-Differential pressure flow meter; 8-Balancing valve; 9-Negative pressure side sampling pipe; 10-Negative pressure side primary valve; 11-Negative pressure side secondary valve; 12-Negative pressure side drain valve;

[0023] 21-Positive pressure side air collector; 22-Positive pressure side exhaust valve; 23-Positive pressure side exhaust pipe; 24-Negative pressure side air collector; 25-Negative pressure side exhaust valve; 26-Negative pressure side exhaust pipe. Detailed Implementation

[0024] The specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of this utility model.

[0025] Please see Figure 1 The prior art provides a liquid differential pressure flow meter, including a sampling tube and a differential pressure flow meter 7 installed on the sampling tube. Both ends of the sampling tube are connected to a throttling device 1. Due to the variable cross-section of the throttling device 1, changes in flow velocity and hydraulic pressure occur when the liquid flows through the throttling device 1. The flow cross-section narrows, and the flow velocity increases. According to Bernoulli's theorem, the increase in kinetic energy leads to a decrease in static pressure. Therefore, the side with lower flow velocity is the positive pressure side, and the side with higher flow velocity is the negative pressure side. Based on the change in liquid pressure within the sampling tube, the sampling tube is divided into a positive pressure side and a negative pressure side. That is, the sampling tube includes a positive pressure side sampling tube 3 and a negative pressure side sampling tube 9. One end of both the positive pressure side sampling tube 3 and the negative pressure side sampling tube 9 is connected to the differential pressure flow meter 7, and the other ends are respectively connected to the large and small cross-section positions of the throttling device 1. From the throttling device 1 to the differential pressure flow meter 7, the positive pressure side sampling pipe 3 is equipped with a positive pressure side primary valve 4 and a positive pressure side secondary valve 5 in sequence, and the negative pressure side sampling pipe 9 is equipped with a negative pressure side primary valve 10 and a negative pressure side secondary valve 11 in sequence, which facilitates the control of the opening and closing of the sampling pipes. A balancing valve 8 is also provided between the positive pressure side sampling pipe 3 and the negative pressure side sampling pipe 9, which is connected in parallel with the differential pressure flow meter. The balancing valve 8 is closed when measuring the liquid pressure difference and open when not measuring.

[0026] Positive pressure side drain valve 6 and negative pressure side drain valve 12 are correspondingly installed on the positive pressure side sampling pipe 3 and negative pressure side sampling pipe 9, respectively. Since the liquid differential pressure flow meter is horizontally arranged, the sampling pipe sections at both ends are also horizontally arranged. Therefore, the drain valve is located at the bottom of this horizontal sampling pipe section. When the liquid in this sampling pipe section does not meet the differential pressure measurement requirements, the liquid mixed with gas is discharged from the drain valve by manually adjusting its opening and closing. Manual draining often increases the workload of personnel, has low operating efficiency, and poses a risk of burns during draining because the liquid often has a high temperature.

[0027] Example 1;

[0028] Please see Figure 2-3 This utility model provides a liquid differential pressure flow meter sewage discharge device, including a sampling tube and a differential pressure flow meter installed on the sampling tube.

[0029] Compared to existing technologies, the biggest difference in this embodiment is that the downward-flowing drain valve has been eliminated, and a pair of exhaust pipes located on both sides of the differential pressure flow meter 7 are installed on the sampling tube. A pair of exhaust valves are installed opposite each other on the exhaust pipes. The exhaust pipes are positioned upwards by default to facilitate exhaust, but the specific tilt angle is not limited, but it is best to be vertically upwards. In particular, the exhaust pipes do not need to discharge high-temperature liquids, thus effectively preventing burns to personnel.

[0030] Specifically, a positive pressure exhaust pipe 23 and a negative pressure exhaust pipe 26 are installed on the pipe sections at both ends of the differential pressure flow meter 7 on the positive pressure side sampling pipe 3 and the negative pressure side sampling pipe 9, respectively. The exhaust pipes are connected to the sampling pipes through a three-way valve. A positive pressure exhaust valve 22 is installed on the positive pressure side exhaust pipe 23, and a negative pressure exhaust valve 25 is installed on the negative pressure side exhaust pipe 26.

[0031] When liquid carrying air bubbles flows to the positions of the positive pressure side exhaust pipe 23 and the negative pressure side exhaust pipe 26, the gas will float on top of the liquid because the gas density is less than that of the liquid. At the same time, the positive pressure side exhaust pipe 23 and the negative pressure side exhaust pipe 26 are equipped with positive pressure side exhaust valve 22 and negative pressure side exhaust valve 25, respectively. There is a certain gap between the exhaust valve and the sampling pipe, and a certain cavity will be formed in the exhaust pipe within this gap. Each time the exhaust valve is opened, a small portion of the liquid in the sampling pipe can be controlled to flow into the cavity, forming a small liquid column. Thus, during liquid differential pressure measurement, the air bubbles that are normally flowing with the liquid in the sampling pipe and floating on the top of the liquid will exchange gas and liquid with the small liquid column in the cavity at the position of the exhaust pipe. The air bubbles will rise to the top of the small liquid column, and the liquid in the small liquid column will flow back into the sampling pipe under the action of air pressure. This test is repeated until the liquid column disappears or the liquid level of the liquid column is very low. Then the exhaust valve is opened again, and the small liquid column is formed again. This cycle is repeated. Since sewage is discharged solely through venting, it effectively prevents personnel from being scalded by the high-temperature liquid, reducing operational risks and ensuring the measurement accuracy of the differential pressure flow meter. Although venting requires opening the vent valve, the automation level of venting and sewage discharge is improved compared to existing technologies.

[0032] The positive pressure side exhaust valve 22 and the negative pressure side exhaust valve 25 can be manual valves, electromagnetic exhaust valves, or even timed electromagnetic exhaust valves. When using manual valves, the exhaust pipe can be made of transparent material, allowing personnel to clearly see the height of the small liquid column inside the exhaust pipe, facilitating valve adjustment. The operating frequency and duration of the electromagnetic exhaust valve and the timed electromagnetic exhaust valve can be set according to process requirements. Alternatively, the height of the small liquid column inside the exhaust pipe can be monitored in real time, and the valve opening can be controlled based on the monitored data. This further reduces workload, achieves more automated and higher-precision measurements, and significantly improves work efficiency. The specific structure and control method of the timed electromagnetic exhaust valve are existing technologies, and many products are available on the market, so they will not be described in detail here.

[0033] Example 2;

[0034] Please see Figure 2-3 Compared to Example 1, the improvement of this example is that: a gas collector is also provided on a pair of exhaust pipes, and the gas collector is located upstream of the exhaust valve.

[0035] Specifically, since the exhaust pipe is upward-facing, the gas is discharged from bottom to top, therefore the upstream of the exhaust valve is the lower part of the exhaust pipe. A positive-pressure side gas collector 21 is installed on the positive-pressure side exhaust pipe 23, located between the positive-pressure side sampling pipe 3 and the positive-pressure side exhaust valve 22. A negative-pressure side gas collector 24 is installed on the negative-pressure side exhaust pipe 26, located between the negative-pressure side sampling pipe 9 and the negative-pressure side exhaust valve 25. The gas collector is equivalent to being installed in the cavity position in Embodiment 1, used to increase the volume of the liquid column in the exhaust pipe, increase the gas-liquid exchange rate, and reduce the number of times the exhaust valve is opened and closed. This can further reduce the workload of personnel. The gas collector can be cylindrical, spherical, or other shapes; this embodiment is not limited to any particular shape.

[0036] The above embodiments are merely illustrative examples for clarity and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all embodiments here. However, any variations or modifications derived therefrom are still within the protection scope of this utility model.

Claims

1. An automatic sewage discharge device for a liquid differential pressure flow meter, comprising a sampling tube and a differential pressure flow meter installed on the sampling tube, characterized in that: The horizontal sampling section of the sampling tube is provided with a pair of exhaust pipes, which are located opposite each other on both sides of the differential pressure flow meter, and exhaust valves are provided opposite each other on the pair of exhaust pipes. The pair of exhaust pipes are also provided with air collectors opposite each other, and the air collectors are located upstream of the exhaust valve.

2. The automatic sewage discharge device for liquid differential pressure flowmeter according to claim 1, characterized in that: The exhaust valve is an electromagnetic exhaust valve.

3. The automatic sewage discharge device for liquid differential pressure flowmeter according to claim 2, characterized in that: The electromagnetic exhaust valve is a timed electromagnetic exhaust valve.

4. The automatic sewage discharge device for liquid differential pressure flowmeter according to claim 3, characterized in that: The pair of exhaust pipes are connected to the sampling pipe via a three-way valve.

5. The automatic sewage discharge device for a liquid differential pressure flow meter according to any one of claims 1-4, characterized in that: The two ends of the sampling tube are connected to a throttling device installed on the liquid pipeline.

6. The automatic sewage discharge device for liquid differential pressure flowmeter according to claim 5, characterized in that: The sampling tube is also equipped with a pair of primary valves near the throttling device, and the pair of primary valves are located on opposite sides of the differential pressure flow meter.

7. The automatic sewage discharge device for liquid differential pressure flowmeter according to claim 6, characterized in that: The sampling tube is also equipped with a pair of secondary valves near the differential pressure flow meter, and the pair of secondary valves are located on opposite sides of the differential pressure flow meter.

8. The automatic sewage discharge device for liquid differential pressure flowmeter according to claim 7, characterized in that: The sampling tube is equipped with a balancing valve connected in parallel with the differential pressure flow meter.

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