Pipeline flue gas constant-speed measurement system

Abstract

The invention relates to the technical field of flue gas measurement, in particular to a pipeline flue gas constant-speed measurement system which comprises a measurement loop, a constant-speed control box and a flue flow velocity sensor arranged in a boiler exhaust pipeline. A measuring nozzle, a differential pressure transmitter, a dust meter and a frequency conversion fan are arranged on the measuring loop; the flue flow velocity sensor, the measuring nozzle, the differential pressure transmitter and the frequency conversion fan are electrically connected with the flue flow velocity sensor; the flue gas flow velocity in the measuring loop is adjusted, so that the flue gas flow velocity in the measuring loop is consistent with the flue gas flow velocity in the boiler exhaust pipeline, then the flue gas flow velocity in the measuring loop is measured, and the measuring precision is higher.

Description

Technical Field

[0001] This invention relates to the field of flue gas measurement technology, specifically to a pipeline flue gas isokinetic measurement system. Background Technology

[0002] Currently, online monitoring of pollution sources typically employs simultaneous measurement of temperature, pressure, and flow rate, primarily to measure flue gas flow under standard conditions. Most existing temperature, pressure, and flow measurement devices utilize Pitot tube flowmeters to measure differential pressure. During measurement, the Pitot tube acts as a sampling probe, extending into the boiler exhaust pipe or other measuring conditions to extract the flue gas for further measurement. A Chinese patent with authorization announcement number CN207600539U discloses a temperature, pressure, and flow measurement device for flue gas detection, including a sampling probe, an inlet pipe, a detector, a backflushing system, and a zero-adjustment protection line. The sampling probe is connected to the inlet pipe, which leads to the detector. The backflushing system is optionally connected to the inlet pipe, backflushing the sampling probe as needed. The zero-adjustment protection line is connected to the inlet pipe between the detector and the backflushing system. During backflushing, the zero-adjustment protection line protects the flow rate detector and simultaneously zeroes it.

[0003] However, in practical applications, the above-mentioned device still has the following shortcomings: after the flue gas is drawn in from the sampling probe, the flue gas velocity in the intake pipe is inconsistent with the flue gas velocity in the boiler exhaust pipe. Directly using the flow rate detector will result in a large error, leading to low final measurement accuracy. Summary of the Invention

[0004] The purpose of this invention is to address the above-mentioned shortcomings by providing a flue gas isokinetic measurement system. By adjusting the flue gas velocity in the measurement circuit to make it consistent with the flue gas velocity in the boiler exhaust pipe, the flue gas velocity in the measurement circuit is then measured, resulting in higher measurement accuracy.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A flue gas isokinetic measurement system includes a measurement circuit, an isokinetic control box, and a flue gas velocity sensor installed in a boiler exhaust pipe. The two ends of the measurement circuit are respectively connected to the boiler exhaust pipe. The measurement circuit is equipped with a measuring nozzle, a differential pressure transmitter, a dust meter, and a variable frequency fan. The flue gas velocity sensor, the measuring nozzle, the differential pressure transmitter, and the variable frequency fan are all electrically connected to the flue gas velocity sensor.

[0007] Furthermore, the measurement circuit includes a measurement sampling tube, a connecting tube, and a return gas line. The two ends of the measurement sampling tube are respectively connected to the boiler exhaust pipe and the differential pressure transmitter. The gas outlet of the differential pressure transmitter is connected to the connecting tube. The gas outlet of the connecting tube is connected to the dust meter. The return gas line is connected to the boiler exhaust pipe and the gas outlet of the dust meter. The variable frequency fan is installed on the return gas line, and the measurement nozzle is installed on the measurement sampling tube.

[0008] Furthermore, the measuring sampling tube is connected upstream of the boiler exhaust pipe, and the return gas pipeline is connected downstream of the boiler exhaust pipe.

[0009] Furthermore, the flue gas velocity sensor is located upstream of the measurement sampling tube.

[0010] Furthermore, flanges are provided at both ends of the measurement circuit.

[0011] The beneficial effects of this invention are:

[0012] In practical applications, a flue gas velocity sensor detects the flue gas velocity in the boiler exhaust pipe and sends the detection result to a constant velocity control box. The control box controls a variable frequency fan to direct the flue gas into the measurement loop based on the detection result. When the measuring nozzle detects that the flue gas velocity in the measurement loop is consistent with that in the internal flue gas duct, a differential pressure transmitter and a dust meter are used to detect dust. The detection result of the differential pressure transmitter is transmitted back to the constant velocity control box. By measuring the dust in the flue gas using the differential pressure transmitter and the dust meter, the measurement result is more accurate. This invention adjusts the flue gas velocity in the measurement loop to make it consistent with the flue gas velocity in the boiler exhaust pipe before measuring the flue gas velocity in the measurement loop, resulting in higher measurement accuracy. Attached Figure Description

[0013] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0014] Figure 1 This is a schematic diagram of the system of the present invention;

[0015] Figure reference numerals: constant velocity control box 1; measuring sampling tube 11; connecting pipe 12; return gas line 13; flange 14; boiler exhaust pipe 2; flue gas velocity sensor 3; measuring nozzle 4; differential pressure transmitter 5; dust meter 6; variable frequency fan 7. Detailed Implementation

[0016] See Figure 1As shown, this embodiment provides a flue gas isokinetic measurement system, including a measurement circuit, an isokinetic control box 1, and a flue gas velocity sensor 3 installed in a boiler exhaust pipe 2. The two ends of the measurement circuit are respectively connected to the boiler exhaust pipe 2. The measurement circuit is equipped with a measuring nozzle 4, a differential pressure transmitter 5, a dust meter 6, and a variable frequency fan 7. The flue gas velocity sensor 3, the measuring nozzle 4, the differential pressure transmitter 5, and the variable frequency fan 7 are all electrically connected to the flue gas velocity sensor 3.

[0017] In use, the flue gas velocity sensor 3 detects the flue gas velocity in the boiler exhaust pipe 2 and sends the detection result to the constant velocity control box 1. The control box controls the variable frequency fan 7 to bring the flue gas into the measurement circuit based on the detection result. When the measuring nozzle 4 detects that the flue gas velocity in the measurement circuit is consistent with that in the inner flue gas pipe, the differential pressure transmitter 5 and the dust meter 6 detect the dust respectively. The detection result of the differential pressure transmitter 5 is transmitted back to the constant velocity control box 1. The measurement of dust in the flue gas by the differential pressure transmitter 5 and the dust meter 6 respectively makes the measurement result more accurate. This invention adjusts the flue gas velocity in the measurement circuit to make the flue gas velocity in the measurement circuit consistent with the flue gas velocity in the boiler exhaust pipe 2, and then measures the flue gas velocity in the measurement circuit, resulting in higher measurement accuracy.

[0018] See Figure 1 As shown, the measurement circuit includes a measurement sampling tube 11, a connecting pipe 12, and a return gas line 13. The two ends of the measurement sampling tube 11 are connected to the boiler exhaust pipe 2 and the differential pressure transmitter 5, respectively. The outlet of the differential pressure transmitter 5 is connected to the connecting pipe 12, and the outlet of the connecting pipe 12 is connected to the dust meter 6. The return gas line 13 connects the boiler exhaust pipe 2 and the outlet of the dust meter 6. The variable frequency fan 7 is installed on the return gas line 13, and the measurement nozzle 4 is installed on the measurement sampling tube 11. In this embodiment, the flue gas velocity in the boiler exhaust pipe 2 is detected by the flue gas velocity sensor 3, and the detection result is sent to the constant velocity control box 1. The control box controls the variable frequency fan 7 to extract the flue gas according to the detection result. When the measurement nozzle 4 detects that the flue gas velocity in the sampling line is consistent with that in the inner flue gas pipe, the dust is detected by the differential pressure transmitter 5 and the dust meter 6, respectively. The detection result of the differential pressure transmitter 5 is transmitted back to the constant velocity control box 1, and the measurement result is more accurate.

[0019] See Figure 1 As shown, the measuring sampling tube 11 is connected to the upstream of the boiler exhaust pipe 2, and the return gas line 13 is connected to the downstream of the boiler exhaust pipe 2. In this embodiment, when the measuring sampling tube 11 is connected to the upstream of the boiler exhaust pipe 2 and the return gas line 13 is connected to the downstream of the boiler exhaust pipe 2, it is easier to extract the flue gas.

[0020] See Figure 1As shown, the flue gas velocity sensor 3 is located upstream of the measuring sampling tube 11; in this embodiment, when the flue gas velocity sensor 3 is located upstream of the measuring sampling tube 11, the measurement result of the flue gas velocity sensor 3 is more accurate.

[0021] See Figure 1 As shown, flanges 14 are provided at both ends of the measurement circuit; in this embodiment, both ends of the measurement circuit are connected to the boiler exhaust pipe 2 through flanges 14.

[0022] The specific embodiments described herein are merely illustrative examples illustrating the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the scope defined by the spirit of the invention.

Claims

1. A flue gas isokinetic measurement system, characterized in that: The device includes a measurement circuit, a constant velocity control box, and a flue gas velocity sensor installed in the boiler exhaust pipe. The two ends of the measurement circuit are respectively connected to the boiler exhaust pipe. The measurement circuit is equipped with a measuring nozzle, a differential pressure transmitter, a dust meter, and a variable frequency fan. The flue gas velocity sensor, the measuring nozzle, the differential pressure transmitter, and the variable frequency fan are all electrically connected to the flue gas velocity sensor.

2. The pipeline flue gas isokinetic measurement system according to claim 1, characterized in that: The measurement circuit includes a measurement sampling tube, a connecting tube, and a return gas line. The two ends of the measurement sampling tube are respectively connected to the boiler exhaust pipe and the differential pressure transmitter. The gas outlet of the differential pressure transmitter is connected to the connecting tube. The gas outlet of the connecting tube is connected to the dust meter. The return gas line is connected to the boiler exhaust pipe and the gas outlet of the dust meter. The variable frequency fan is installed on the return gas line, and the measurement nozzle is installed on the measurement sampling tube.

3. The pipeline flue gas isokinetic measurement system according to claim 2, characterized in that: The measuring sampling tube is connected upstream of the boiler exhaust pipe, and the return gas pipeline is connected downstream of the boiler exhaust pipe.

4. The pipeline flue gas isokinetic measurement system according to claim 3, characterized in that: The flue gas velocity sensor is located upstream of the measurement sampling tube.

5. The pipeline flue gas isokinetic measurement system according to claim 1, characterized in that: Flanges are provided at both ends of the measurement circuit.

Images