Anti-blocking flow measuring device for atmospheric emission monitoring

Abstract

The application discloses a kind of flow measuring devices of anti-blocking type for atmospheric emission monitoring, it includes positive pressure sampling end and negative pressure sampling end inserted in air duct obliquely, wherein positive pressure sampling end is installed below negative pressure sampling end, and positive pressure sampling end and negative pressure sampling end are both hollow tubular structure, the positive pressure sampling end includes positive pressure sampling tube, several positive pressure sensing points being opened in the positive pressure sampling tube directly below, a polytene cylinder is installed below each positive pressure sensing point, and a first spiral ash cleaning device is installed in the positive pressure sampling tube;The negative pressure sampling end includes negative pressure sampling tube, several negative pressure sensing points being opened in the side of negative pressure sampling tube, and a second spiral ash cleaning device is installed in the negative pressure sampling tube;The application realizes multipoint sampling by multiple sensing points on positive pressure sampling tube and negative pressure sampling tube, solves the problem that sampling is difficult for large cross-section gas emission pipeline, and the spiral ash cleaning device at the end of positive pressure sampling tube and negative pressure sampling tube removes ash and sundries accumulated in the tube, so that the device can be used reliably for a long time.

Description

[Technical Field]

[0001] This invention relates to the field of atmospheric emission monitoring, and specifically to an anti-clogging flow measurement device for atmospheric emission monitoring. [Background Technology]

[0002] With the development of the times and the progress of society, protecting and improving the environment and preventing air pollution have become urgent tasks. Flow monitoring is also an important indicator, but the existing measurement devices have the following problems:

[0003] 1. Due to the large cross-section and short straight sections of many discharge pipes, the gas flow field distribution inside the pipe is extremely uneven, especially when the load changes, the flow field inside the pipe also changes accordingly. It is impossible to accurately measure the actual flow rate using a single point or a few points.

[0004] 2. The exhaust gas contains impurities such as ash and water, and the atmospheric emission flow monitoring devices are prone to blockage, making them unreliable for long-term use.

[0005] 3. Due to the large cross-section of the gas emission pipe and the low flow velocity inside the pipe, the existing measuring devices generate small differential pressures and have low measurement accuracy.

[0006] Therefore, providing an accurate and reliable flow measurement device is a problem that urgently needs to be solved in this field. [Summary of the Invention]

[0007] To address the aforementioned problems, this invention proposes a flow measurement device for atmospheric emission monitoring, comprising a positive pressure sampling end and a negative pressure sampling end inserted at an angle into a pipe. The positive pressure sampling end is installed below the negative pressure sampling end, and both the positive and negative pressure sampling ends are hollow tubular structures. The positive pressure sampling end includes a positive pressure sampling tube and several positive pressure sensing points located directly below the positive pressure sampling tube. A pressure-gathering cylinder is installed below each positive pressure sensing point, and a first spiral cleaning device is installed inside the positive pressure sampling tube. The negative pressure sampling end includes a negative pressure sampling tube and several negative pressure sensing points located on the side of the negative pressure sampling tube, and a second spiral cleaning device is installed inside the negative pressure sampling tube.

[0008] Furthermore, the first spiral cleaning device includes a first rectangular spring inserted inside the positive pressure sampling tube, one end of which extends out of the positive pressure sampling tube and is connected to a first motor.

[0009] Furthermore, the positive pressure sampling tube is sealed at one end inside the pipe, while the negative pressure sampling tube remains open at one end inside the pipe.

[0010] Furthermore, the lower edges of the first rectangular spring and the second rectangular spring abut against the inner walls of the positive and negative pressure sampling tubes, respectively.

[0011] Furthermore, a positive pressure lead-out pipe is welded to the outer wall of the positive pressure sampling tube, and the lead-out point of the positive pressure lead-out pipe is located at the geometric center of the line connecting several positive pressure sensing points.

[0012] Furthermore, a negative pressure lead-out pipe is welded to the outer wall of the negative pressure sampling tube, and the lead-out point of the negative pressure lead-out pipe is located at the geometric center of the line connecting several negative pressure sensing points.

[0013] Furthermore, both the first and second spiral cleaning devices are connected to a programmable controller, which controls the working time of the spiral cleaning devices.

[0014] Compared with the prior art, the present invention has the following advantages:

[0015] 1. This invention achieves multi-point sampling through multiple sensing points on positive and negative pressure sampling tubes, solving the problem of difficult sampling due to the large cross-section of gas emission pipelines.

[0016] 2. This invention removes accumulated dust and other debris from the tube by using a spiral cleaning device at the end of the positive and negative pressure sampling tube, enabling the device to be used reliably for a long time.

[0017] 3. This invention increases the pressure at the positive pressure sensing point on the windward side by using a pressure-gathering cylinder below the positive pressure sampling tube, thereby increasing the pressure difference between total pressure and static pressure and improving measurement accuracy.

[0018] 4. This invention achieves true pressure equalization by taking the sampling tube pressure at the geometric center of each sensing point, thus improving measurement accuracy. [Attached Image Description]

[0019] Figure 1 This is a schematic diagram of the anti-clogging flow measurement device for atmospheric emission monitoring according to the present invention.

[0020] Figure 2 This is a schematic diagram for measuring a rectangular cross-section pipe.

[0021] Figure 3 This is the installation angle value table for this invention.

Detailed Implementation Methods

[0022] The directional terms used in this invention, such as "up", "down", "front", "back", "left", "right", "inner", "outer", and "side", are merely directions in the accompanying drawings and are used only to explain and illustrate this invention, not to limit the scope of protection of this invention.

[0023] See Figure 1 and Figure 2The present invention provides the structural composition of an anti-clogging flow measurement device for atmospheric emission monitoring, comprising a positive pressure sampling end 2 and a negative pressure sampling end 3 inserted at an angle into a pipe 1. The positive pressure sampling end 2 is installed below the negative pressure sampling end 3, and both the positive pressure sampling end 2 and the negative pressure sampling end 3 are hollow tubular structures. When there is airflow in the pipe 1, the kinetic energy of the airflow at the positive pressure sampling end is converted into pressure energy. As the windward side, the pressure inside the pipe is relatively high, and this pressure is called the "total pressure". Since the negative pressure sampling end is not subjected to airflow pressure, the pressure inside its pipe is the static pressure inside the pipe. The difference between the total pressure and the static pressure is called the differential pressure. The larger the flow rate, the larger the differential pressure; conversely, the smaller the flow rate, the smaller the differential pressure. According to the Bernoulli equation principle, the magnitude of the flow rate is proportional to the root mean square of the differential pressure. Therefore, as long as the magnitude of the differential pressure is measured, the actual flow rate inside the pipe can be accurately measured.

[0024] The positive pressure sampling end 2 includes a positive pressure sampling tube 201 and several positive pressure sensing points 202 located directly below the positive pressure sampling tube 201. The end of the positive pressure sampling tube 201 located inside the pipeline is sealed. A positive pressure outlet tube 203 is welded to the outer wall of the positive pressure sampling tube 201. The outlet point of the positive pressure outlet tube is located at the geometric center of the line connecting several positive pressure sensing points. A pressure-gathering cylinder 204 is installed below each positive pressure sensing point 202. In addition, a first spiral dust removal device 4 is installed inside the positive pressure sampling tube.

[0025] The negative pressure sampling end 3 has a similar structure to the positive pressure sampling end 2, including a negative pressure sampling tube 301 and several negative pressure sensing points 302 opened on the side of the negative pressure sampling tube; one end of the negative pressure sampling tube inside the pipe is kept open, and a negative pressure outlet tube 303 is welded to the outer wall of the negative pressure sampling tube 301. The outlet point of the negative pressure outlet tube is located at the geometric center of the line connecting several negative pressure sensing points. In addition, a second spiral dust removal device 5 is installed inside the negative pressure sampling tube.

[0026] Both the first spiral cleaning device 4 and the second spiral cleaning device 5 are connected to a programmable controller 6, which controls the working time of the spiral cleaning device.

[0027] The first spiral cleaning device 4 includes a first rectangular spring 401 (i.e., a spring with a rectangular cross-section of the spring wire) inserted inside the positive pressure sampling tube 201. One end of the first rectangular spring extends out of the positive pressure sampling tube and is connected to a first motor 402 through a sealing shaft (not shown). The lower edge of the first rectangular spring abuts against the inner wall of the positive pressure sampling tube. During the measurement process, the first motor drives the first rectangular spring to rotate. During the rotation, the accumulated dust in the positive pressure sampling tube is transported to the positive pressure sensing point 202 and falls into the pipe from the positive pressure sensing point and is carried out by the airflow.

[0028] The second spiral cleaning device 5 includes a second rectangular spring 501 inserted inside the negative pressure sampling tube 301. One end of the second rectangular spring extends out of the negative pressure sampling tube and is connected to a second motor 502 through a sealing shaft (not shown). The lower edge of the second rectangular spring abuts against the inner wall of the negative pressure sampling tube. During the measurement process, the second motor drives the second rectangular spring to rotate. During the rotation, the accumulated dust in the negative pressure sampling tube is transferred to the end of the negative pressure sampling tube 301 and falls into the pipe from the end opening, where it is carried out by the airflow.

[0029] Example 1

[0030] Both the positive pressure sampling tube 201 and the negative pressure sampling tube 301 are rectangular tubes. Several rectangular holes are opened at the bottom of the positive pressure sampling tube as positive pressure sensing points 202. A pressure-gathering cylinder 204 is connected directly below each positive pressure sensing point 202, and the pressure-gathering cylinder is a rectangular tube with its opening facing downward.

[0031] Example 2

[0032] Both the positive pressure sampling tube 201 and the negative pressure sampling tube 301 are circular tubes. Several circular holes are opened at the bottom of the positive pressure sampling tube as positive pressure sensing points 202. A pressure-gathering cylinder 204 is connected directly below each positive pressure sensing point 202, and the pressure-gathering cylinder is a circular tube with its opening facing downward.

[0033] The measurement principle of the flow measurement device for atmospheric emission monitoring in this invention is as follows:

[0034] According to the national standard GB / T 16157-1996, "Methods for Determination of Particulate Matter and Sampling of Gaseous Pollutants in Exhaust Gas from Stationary Sources," when the pipe cross-section is circular, several equally sized circular rings are virtually divided within the circular cross-section. The projection of the positive pressure sensing point is as follows: Figure 1 As shown, the airflow falls within an equal-area circular ring. When the airflow from bottom to top passes the positive pressure sensing point, the pressure is increased by the pressure-gathering effect of the pressure-gathering cylinder 204 to form total pressure. The negative pressure sampling tube is located on the leeward side, and the pressure inside the tube is equal to that in the pipeline to form static pressure. The total pressure and static pressure are introduced into the differential pressure transmitter through the positive pressure lead-out pipe 203 and the negative pressure lead-out pipe 303, respectively. The airflow rate in the pipeline is calculated through the pressure difference.

[0035] See Figure 2 When the pipe cross-section is rectangular, the measurement principle is similar to that of a circular cross-section. The difference is that, in accordance with the relevant requirements of the national standard "Methods for Determination of Particulate Matter and Sampling of Gaseous Pollutants in Exhaust Gas from Stationary Sources", multiple insertion points are used to arrange sampling points at multiple points for square and rectangular cross-sections. The differential pressure signals of each point are then combined outside the pipe to obtain the actual flow rate value inside the pipe.

[0036] Particulate matter is a significant contributor to air pollution and blockages. Based on the relevant provisions of the national standard GB 13271-2014 "Emission Standard of Air Pollutants for Boilers," experiments were conducted to determine the correlation between particulate matter concentration and the angle α of the measuring device inserted into the pipe. Figure 3 As shown.

[0037] (If there is moisture in the air pollutants emitted, the tilt angle of the measuring device shall not be less than 5°.)

[0038] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A clog-resistant flow measurement device for monitoring atmospheric emissions, characterized in that, The anti-clogging flow measurement device for atmospheric emission monitoring includes a positive pressure sampling end (2) and a negative pressure sampling end (3) that are inclinedly inserted into a pipe (1). The positive pressure sampling end (2) is installed below the negative pressure sampling end (3). Both the positive pressure sampling end (2) and the negative pressure sampling end (3) are hollow tubular structures. The positive pressure sampling end (2) includes a positive pressure sampling tube (201) and several positive pressure sensing points (202) opened directly below the positive pressure sampling tube (201). A pressure-gathering cylinder (204) is installed below each positive pressure sensing point (202). A first spiral cleaning device (4) is installed inside the positive pressure sampling tube. The negative pressure sampling end (3) includes a negative pressure sampling tube (301) and several negative pressure sensing points (302) opened on the side of the negative pressure sampling tube. A second spiral cleaning device (5) is installed inside the negative pressure sampling tube. The first spiral cleaning device (4) includes a first rectangular spring (401) inserted inside the positive pressure sampling tube (201), one end of the first rectangular spring extending out of the positive pressure sampling tube and connected to a first motor (402); The positive pressure sampling tube (201) is sealed at one end inside the pipe, while the negative pressure sampling tube (301) is kept open at one end inside the pipe. The lower edges of the first rectangular spring (401) and the second rectangular spring (501) abut against the inner walls of the positive and negative pressure sampling tubes, respectively. The outer wall of the positive pressure sampling tube (201) is welded with a positive pressure lead-out tube (203), and the lead-out point of the positive pressure lead-out tube is located at the geometric center of the line connecting several positive pressure sensing points; The outer wall of the negative pressure sampling tube (301) is welded with a negative pressure lead-out tube (303), and the lead-out point of the negative pressure lead-out tube is located at the geometric center of the line connecting several negative pressure sensing points. Both the first spiral cleaning device (4) and the second spiral cleaning device (5) are connected to a programmable controller (6), which controls the working time of the spiral cleaning device.

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