Wind measuring device for local ventilation fan in mine

Abstract

The present invention relates to a wind measuring device for a local ventilation fan in a mine, and belongs to a wind measuring device for a fan. The technical solution adopted by the present invention is: it includes an inlet cone section and a cylinder section, the inlet cone section is a conical cylinder, the cylinder section is a cylindrical cylinder, the conical shrinkage end of the inlet cone section is connected to one end of the cylinder section, the flared end of the inlet cone section faces outward as an air suction port, the other end of the cylinder section is connected to the air inlet of the local ventilation fan, and a through pressure measuring hole is opened on the side wall of the cylinder section. A steel pipe is arranged at the opening of the outer side of the pressure measuring hole of the cylinder section, and the steel pipe is connected to a pressure gauge through a rubber hose. The advantages of the present invention are: the original measurement of the air inlet and air outlet ends of the fan is simplified to the measurement of the air inlet end, which simplifies the measuring equipment; it can be adapted to the ventilator after maintenance.

Description

Technical Field

[0001] The invention relates to a wind measuring device for a local ventilator in a mine, belonging to a wind measuring device for a ventilator. Background Art

[0002] The air consumption locations of underground coal mining mainly include coal mining working faces, tunneling working faces and independently ventilated chambers, among which the air consumption of tunneling working faces accounts for more than 50% of the total air volume of the mine. The reason why the air volume required for local ventilation accounts for a large proportion of the total air volume of the mine is that there are many local fans used in the mine. Therefore, it is very important to accurately calculate the actual air volume required in the mine and measure the actual air volume required by the local fan. How to measure the air volume required by the local fan? The current methods include calculating the theoretical air intake volume according to the product manual, or calculating the air intake volume of the local fan by measuring the air volume before and after the local fan is installed in the lane. The first method is feasible for new fans, but the air intake volume of the local fan after maintenance has a large change, and it is not scientific to calculate it with the theoretical value. The second method requires measuring the air volume at the two sections before and after the fan. Due to the existence of the local fan, it has a great influence on the accuracy of wind measurement, and the calculated air volume is very inaccurate. Summary of the invention

[0003] In order to accurately measure the air suction volume of the local ventilator, a wind measuring device for the local ventilator in this mine was designed and manufactured.

[0004] To achieve the above object, the technical solution adopted by the present invention is:

[0005] The invention discloses a wind measuring device for a local ventilation fan in a mine, comprising an inlet cone section and a cylinder section, wherein the inlet cone section is a conical cylinder, and the cylinder section is a cylindrical cylinder. The conical shrinkage end of the inlet cone section is connected to one end of the cylinder section, and the flared end of the inlet cone section faces outward as an air suction port, and the other end of the cylinder section is connected to the air inlet of the local ventilation fan. A penetrating pressure measuring hole is opened on the side wall of the cylinder section, and a steel pipe is arranged at the opening on the outer side of the pressure measuring hole of the cylinder section, and the steel pipe is connected to the pressure gauge through a rubber hose.

[0006] Preferably, the distance between the center of the pressure measuring hole and the welding point between the inlet cone section and the cylindrical section is 400 mm, and the pressure measuring holes are divided into four groups and evenly distributed on the cylindrical section.

[0007] Preferably, the diameter of the pressure measuring hole is 100 mm, the inner diameter surface of the pressure measuring hole has a smooth transition with the inner surface of the cylindrical section, the roughness does not exceed 80 μm, and the inner diameter of the steel pipe is 60 mm.

[0008] Preferably, the inlet cone section and the cylindrical section are metal cylinder structures, which are welded together, the thickness of the inlet cone section and the cylindrical section is 3 mm, and the roughness Ra of the welding position is less than 80 μm.

[0009] The advantages of the present invention are that the original measurement of the air inlet and air outlet ends of the fan is simplified to measurement of the air inlet end, thereby simplifying the measurement equipment and being adaptable to the fan after maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a structural diagram of the present invention,

[0011] Figure 2 It is a right side view of the present invention.

[0012] Figure 3 It is an installation structure diagram of the present invention.

[0013] Figure numerals: 1. inlet cone section, 2. cylindrical section, 3. pressure measuring hole, 4. steel pipe, 5. pressure gauge, 6. rubber hose, 7. local ventilator. DETAILED DESCRIPTION

[0014] The specific structure of the present invention is as follows Figure 1 and Figure 2 As shown, a wind measuring device for a local ventilation fan in a mine comprises an inlet cone section 1 and a cylinder section 2. The inlet cone section 1 is a conical cylinder, and the cylinder section 2 is a cylindrical cylinder. The conical shrinkage end of the inlet cone section 1 is connected to one end of the cylinder section 2, and the flared end of the inlet cone section 1 faces outward as an air suction port. The other end of the cylinder section 2 is connected to the air inlet of the local ventilation fan. A penetrating pressure measuring hole 3 is opened on the side wall of the cylinder section 2. A steel pipe 4 is arranged at the opening on the outer side of the pressure measuring hole 3 of the cylinder section 2. The steel pipe 4 is connected to a pressure gauge 5 through a rubber hose 6.

[0015] The center position of the pressure measuring hole 3 is in the center of the cylindrical section, and the distance from the inlet and outlet of the cylindrical section 2 is 400 mm. The pressure measuring holes 3 are evenly distributed on the cylindrical section 2 in four groups.

[0016] The diameter of the pressure measuring hole 3 is 10 mm, the inner diameter surface of the pressure measuring hole 3 and the inner surface of the cylindrical section 2 are smoothly transitioned, and the roughness does not exceed 80 μm. The inner diameter of the steel pipe 4 is 60 mm. The inlet cone section 1 and the cylindrical section 2 are metal cylinder structures, and the two are welded together. The thickness of the inlet cone section 1 and the cylindrical section 2 is 3 mm, and the roughness Ra of the welding position is less than 80 μm.

[0017] The production and installation process of this device:

[0018] The material used is a 3mm thick steel plate, and a conical inlet cone section 1 and a cylindrical cylinder section 2 are processed. The inlet cone section 1 and the cylinder section 2 are connected by welding, and the roughness Ra of the welded part is less than 80μm. The specific dimensions of each component are designed according to the air inlet size of the local fan, and the processing deviation does not exceed 1% of the design size. The pressure measuring hole has a diameter of 100mm and is evenly distributed on the same cross section of the cylinder section 2. The inner opening of the hole is cut at a 45° angle, and the transition is smooth with the inner surface. The roughness does not exceed 80μm, and the length from the center of the pressure measuring hole to the welding point is 400mm.

[0019] The device is installed on the silencer in front of the local fan and connected by a flange. A steel pipe with an inner diameter of 60 mm is welded on the cylindrical section 2 where the pressure measuring hole 3 is located. The steel pipe and the pressure gauge are connected by a rubber hose. The air volume of the local fan is calculated by reading the static pressure at this location.

[0020] The method for calculating the air volume of the local ventilator using this device is as follows:

[0021] When using the Bernoulli equation to calculate the air volume of a local fan, it is first assumed that the air volume (fluid) in the fan duct is incompressible, that is, the flow rate is constant, the distance between the two pressure measuring sections is small, the ventilation resistance can be ignored, and the elevations and potential pressures of the two pressure measuring sections are equal. In addition, the conical inlet cylindrical section 1 is simplified to the atmospheric environment, and the cross section is infinite, so the inlet wind speed can be considered to be "0". Considering the correction coefficient of the local fan wind measuring device, the air volume calculation formula is:

[0022] Where:

[0023]

[0024] Q ——Suction volume of local ventilator, m 3 / min;

[0025] S——cross-sectional area of ​​wind measurement section, m 2 ;

[0026] p ——The static air pressure at the wind measuring section, Pa, where the average value is obtained by the pressure gauges connected to the four pressure measuring holes;

[0027] ρ ——Air density in the air duct, kg / m 3；

[0028] The correction coefficient for the local fan and the correction coefficient for the wind measuring device for the local fan are obtained through a large number of tests and statistical analysis of data. Two different measurement methods can be used to measure simultaneously, and the results can be compared and obtained using the linear regression method.

Claims

1. A wind measuring device for a local ventilator in a mine, characterized in that: The invention comprises an inlet cone section (1) and a cylinder section (2), wherein the inlet cone section (1) is a cone-shaped cylinder, and the cylinder section (2) is a cylindrical cylinder. The conical shrinkage end of the inlet cone section (1) is connected to one end of the cylinder section (2), and the expanded end of the inlet cone section (1) faces outward as an air suction port. The other end of the cylinder section (2) is connected to the air inlet of a local ventilator. A penetrating pressure measuring hole (3) is opened on the side wall of the cylinder section (2). A steel pipe (4) is arranged at the opening of the outer side surface of the pressure measuring hole (3) of the cylinder section (2), and the steel pipe (4) is connected to a pressure gauge (5) through a rubber hose (6). The center position of the pressure measuring hole (3) is in the center of the cylindrical section, and the distance from the inlet and outlet of the cylindrical section (2) is 400 mm. The pressure measuring holes (3) are four groups, which are evenly distributed on the circumference of the cylindrical section (2); The diameter of the pressure measuring hole (3) is 10 mm, the inner diameter surface of the pressure measuring hole (3) and the inner surface of the cylindrical section (2) have a smooth transition, and the roughness does not exceed 80 μm. The inner diameter of the steel pipe (4) is 60 mm; The inlet cone section (1) and the cylindrical section (2) are metal cylinder structures, which are welded together. The thickness of the inlet cone section (1) and the cylindrical section (2) is 3 mm, and the roughness Ra of the welding position is less than 80 μm. The manufacturing and installation process of the wind measuring device is as follows: a 3mm thick steel plate is selected as the material, and a conical inlet cone section (1) and a cylindrical cylinder section (2) are processed. The inlet cone section (1) and the cylinder section (2) are connected by welding, and the roughness Ra of the welded part is less than 80μm; the specific dimensions of each component are designed according to the air inlet dimension of the local ventilator, and the processing deviation does not exceed 1% of the designed dimension. The pressure measuring holes have a diameter of 10mm and are evenly distributed on the same cross section of the cylinder section (2). The inner opening of the hole is cut at a 45° angle to smoothly transition with the inner surface, and the roughness does not exceed 80μm. The length from the center of the pressure measuring hole to the welding point is 400mm; The wind measuring device is installed on the silencer in front of the local fan and connected by a flange. A steel pipe with an inner diameter of 60 mm is welded on the cylindrical section (2) where the pressure measuring hole (3) is located. The steel pipe and the pressure gauge are connected by a rubber hose. The air volume of the local fan is calculated by reading the static pressure at the location. The method for calculating the air volume of the local ventilator using the wind measuring device is as follows: When using the Bernoulli equation to calculate the air volume of the local fan, it is first assumed that the air volume in the fan duct is incompressible, that is, the flow rate is constant, the distance between the two pressure measuring sections is small, the ventilation resistance can be ignored, the elevations of the two pressure measuring sections are equal, and the potential pressures are equal; the inlet cone section (1) is simplified to the atmospheric environment, the section is infinite, the inlet wind speed is considered to be 0, and the correction coefficient of the local fan wind measuring device is considered. The air volume calculation formula is: Where: Q——air suction volume of local ventilator, m 3 / min; S——the cross-sectional area of ​​the wind measurement section, m 2 ; p——static air pressure at the wind measuring section, Pa; the static air pressure at the wind measuring section is the average value of the pressure gauges connected to the four pressure measuring holes; ρ——air density in the air duct, kg / m 3 .

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