Pressure Measuring Device

Abstract

To provide a pressure measuring device of a dust-collecting duct that can be maintained easily, is in a configuration of low manufacturing costs, can appropriately prevent clogging of a pipeline with dust, and can accurately measure pressure within the dust-collecting duct by a pressure gauge.SOLUTION: A pressure measuring device 10 includes a pipe 11 in which one end 11a is mounted to a mount hole 2 formed on an outer peripheral surface 1a of a dust-collecting duct 1 and a pressure gauge 15 for measuring pressure within the dust-collecting duct 1 is mounted to an other end 11b. The pipe 11 is mounted to the mount hole 2 while being tilted at 30° to 45° relative to a circulation direction (direction of an arrow A) of exhaust within the dust-collecting duct. An outside air intake hole 16 for taking in outside air from a lower portion is formed at the center in the longitudinal direction of the pipe 11. An outer diameter X (mm) of the pipe 11 and a diameter Y (mm) of the outside air intake hole 16 are set so as to satisfy the following formulas (1), (2): 60.5≤X≤114.3...(1), and 0.08X+2<Y<0.51X-18...(2).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a pressure measuring device for measuring the pressure inside a dust collection duct that collects dust by passing exhaust gas containing dust through the duct. [Background technology]

[0002] Conventionally, in steelworks factories, dust collectors equipped with dust collection ducts that circulate and collect exhaust gas containing dust generated by combustion, etc. are installed. The dust collectors purify the exhaust gas containing dust collected in the dust collection duct and release the purified air into the atmosphere. If the dust collection duct becomes clogged with dust, it will not be able to collect dust properly, so it is necessary to monitor whether the dust collection duct is clogged with dust.To monitor this, a pressure measuring device is used to measure the pressure inside the dust collection duct, and if the measured pressure is greater than a predetermined value, it is determined that the dust collection duct is clogged with dust, and appropriate measures are then taken.

[0003] Here, in a pressure measuring device, a mounting hole is generally provided on the outer peripheral surface of the dust collection duct, a pipe is attached to this mounting hole, a pressure gauge is installed at the tip of this pipe, and the pressure inside the dust collection duct is measured using this pressure gauge. However, this pressure measurement device had the problem that the pressure inside the dust collection duct could not be measured accurately in a short time using the pressure gauge due to dust clogging the inside of the piping, which required the laborious task of manually cleaning the inside of the piping about once a week.

[0004] To address this issue, a pressure detection pipe clogging prevention device has been proposed in the past, for example, as shown in Patent Document 1. The pressure detection tube clogging prevention device disclosed in Patent Document 1 includes an upstream pressure detection tube having one open end on the inlet side of the dust collector and a downstream pressure detection tube having one open end on the outlet side of the dust collector. The pressure detection tube clogging prevention device also includes pressure detection units that detect the pressures inside the upstream pressure detection tube and the downstream pressure detection tube, respectively, and a compressed air supply source to which the other ends of the upstream pressure detection tube and the downstream pressure detection tube are connected and that supplies compressed air to the upstream pressure detection tube and the downstream pressure detection tube. During operation of the dust collector, the compressed air supply source supplies compressed air from the other end of the upstream pressure detection tube at a pressure equal to or greater than the pressure on the inlet side of the dust collector, and supplies compressed air from the other end of the downstream pressure detection tube at a pressure equal to or greater than the pressure on the outlet side of the dust collector.

[0005] The pressure detection tube clogging prevention device disclosed in Patent Document 1 can appropriately prevent dust-containing gas from flowing into each pressure detection tube from the dust collector side while the dust collector is in operation. This makes it possible to appropriately prevent each pressure detection tube from being clogged with dust while the dust collector is in operation, and allows the pressure detection unit to accurately measure pressure (differential pressure within the dust collector). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-35313 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the conventional pressure detection pipe clogging prevention device shown in Patent Document 1 has the following problems. That is, in the case of the pressure detection tube clogging prevention device shown in Patent Document 1, a compressed air supply source is required to supply compressed air to the upstream pressure detection tube and the downstream pressure detection tube. The installation of this compressed air supply source is costly, and maintenance of the compressed air supply source is troublesome. When there are many upstream pressure detection tubes and many downstream pressure detection tubes, many compressed air supply sources are required, which increases the installation cost and maintenance effort of the compressed air supply sources.

[0008] Therefore, the present invention has been made to solve this conventional problem, and its object is to provide a dust collection duct pressure measuring device that is easy to maintain, has a configuration with low manufacturing costs, can appropriately prevent the inside of the piping from becoming clogged with dust, and can accurately measure the pressure inside the dust collection duct using a pressure gauge. [Means for solving the problem]

[0009] In order to solve the above problems, one aspect of the present invention provides a pressure measuring device having a pipe with one end attached to a mounting hole formed in the outer peripheral surface of a dust collection duct that collects dust by circulating exhaust gas containing dust, and the other end having a pressure gauge attached to measure the pressure inside the dust collection duct, wherein the pipe is attached to the mounting hole at an angle of 30° to 45° with respect to the flow direction of the exhaust gas inside the dust collection duct, and an outside air intake hole is formed in the center of the longitudinal direction of the pipe to take in outside air from below, and the outer diameter X (mm) of the pipe and the diameter Y (mm) of the outside air intake hole are set to satisfy the following equations (1) and (2): 60.5≦X≦114.3 (1) 0.08X+2 <Y<0.51X-18 ···(2) [Effects of the Invention]

[0010] The dust collection duct pressure measuring device of the present invention is easy to maintain and has low manufacturing costs, can appropriately prevent the piping from becoming clogged with dust, and can accurately measure the pressure inside the dust collection duct using a pressure gauge. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a partial cross-sectional view of a state in which a pressure measuring device according to an embodiment of the present invention is attached to a dust collection duct. [Figure 2] 2 is a partial cross-sectional view of the pressure measuring device shown in FIG. 1 in a state where the pressure gauge is separated from the piping together with the socket. [Figure 3] 1 is a partial cross-sectional view of a state in which a pressure measuring device according to a first reference example is attached to a dust collection duct. [Figure 4] FIG. 10 is a partial cross-sectional view of a pressure measuring device according to a second reference example attached to a dust collection duct. [Figure 5] FIG. 10 is a partial cross-sectional view of a pressure measuring device according to a third reference example attached to a dust collection duct. [Figure 6] 10 is a graph showing the relationship between the diameter of the outside air intake hole, the pressure value (negative pressure) in the collected dust, and the dust accumulation rate when the piping size is 50A. [Figure 7] 10 is a graph showing the relationship between the diameter of the outside air intake hole and the pressure value (negative pressure) in the collected dust and the dust accumulation rate when the piping size is 80A. [Figure 8] 10 is a graph showing the relationship between the diameter of the outside air intake hole and the pressure value (negative pressure) in the collected dust and the dust accumulation rate when the piping size is 100A. [Figure 9] 10 is a graph showing the relationship between the outer diameter of a pipe and the diameter of an outside air intake hole. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments shown below are examples of devices and methods for embodying the technical concept of the present invention, and the technical concept of the present invention is not limited to the following embodiments in terms of the materials, shapes, structures, arrangements, etc. of the components. In addition, the drawings are schematic, and therefore it should be noted that the relationship between thickness and planar dimensions, ratios, etc. may differ from the actual relationship, and the drawings may also contain parts where the relationship and ratio of dimensions differ from each other.

[0013] FIG. 1 shows a partial cross section of a pressure measuring device according to one embodiment of the present invention attached to a dust collection duct. 1, dust collection duct 1 collects dust-containing exhaust air generated by combustion and other processes in a steelworks factory by circulating it in a flow direction (from bottom to top, as indicated by arrow A). A dust collector (not shown) then purifies the dust-containing exhaust air collected by dust collection duct 1 and releases the purified air into the atmosphere. A dust collector having dust collection duct 1 is used, for example, to collect dust between belt conveyors that transport powder.

[0014] 1 and 2, the dust collection duct 1 is a circular tube having an outer diameter DD, and has a mounting hole 2 formed in its outer peripheral surface 1a. This mounting hole 2 is formed so as to penetrate from the outside to the inside of the dust collection duct 1. The mounting hole 2 is a hole for mounting a pipe 11 of a pressure measuring device 10, which will be described later. The pressure measuring device 10 measures the pressure inside the dust collection duct 1. If the dust collection duct 1 becomes clogged with dust, it will not be able to collect dust properly, so it is necessary to monitor whether dust has become clogged inside the dust collection duct 1. As a monitoring method, the pressure inside the dust collection duct 1 is measured by the pressure measuring device 10, and if the measured pressure is greater than a predetermined value, it is determined that dust has become clogged inside the dust collection duct 1, and then measures are taken.

[0015] The pressure measuring device 10 includes a pipe 11 and a pressure gauge 15 . One end 11a of the pipe 11 is attached to a mounting hole 2 formed in the outer peripheral surface 1a of the dust collection duct 1, and the other end 11b is attached to a pressure gauge 15 that measures the pressure inside the dust collection duct 1. The attachment of the pressure gauge 15 will be described in detail later. The pipe 11 is a metal pipe whose pipe size (outer diameter size) is specified by JIS standards. In this embodiment, the pipe 11 has a pipe size of 50A (outer diameter X of the pipe 11 is 60.5 mm) to 100A (outer diameter X of the pipe 11 is 114.3 mm) and is attached to the mounting hole 2 by welding.

[0016] Here, if dust 17 clogs the inside of the pipe 11, it may be impossible to accurately measure the pressure inside the dust collection duct 1 with the pressure gauge 15 in a short time. This problem will be explained using an example in which a pressure measuring device according to a first reference example shown in Fig. 3 is attached to a dust collection duct. In Fig. 3, the same components as those shown in Fig. 1 are given the same reference numerals, and their explanation may be omitted. In the pressure measuring device 100 of the first reference example shown in Figure 3, one end 11a of the pipe 11 is attached to a mounting hole 2 formed in the outer surface 1a of the dust collection duct 1, and a pressure gauge 15 that measures the pressure inside the dust collection duct 1 is attached to the other end 11b.

[0017] The pipe 11 has a center line CL 11 One end 11a is attached to the mounting hole 2 so that the direction of flow of exhaust air in the dust collection duct 1 (the direction indicated by arrow A, the direction in which the dust collection duct 1 extends) is perpendicular to the direction of flow of exhaust air in the dust collection duct 1. In other words, the piping 11 is attached to the mounting hole 2 formed in the outer peripheral surface 1a of the dust collection duct 1 so that the direction of flow of exhaust air in the dust collection duct 1 is perpendicular to the direction of flow of exhaust air in the dust collection duct 1. Dust 17 flowing inside dust collection duct 1 moves into pipe 11 along the direction indicated by arrow D. In the case of the first modified example, pipe 11 is attached to mounting hole 2 perpendicular to the flow direction of exhaust gas inside dust collection duct 1, so that dust 17 accumulates inside pipe 11 and the inside of pipe 11 becomes clogged with dust 17. This may prevent pressure gauge 15 from accurately measuring the pressure inside dust collection duct 1 in a short time.

[0018] In contrast to this, in the pressure measuring device 10 according to this embodiment, as shown in FIG. 1, the pipe 11 is cut obliquely at one end 11a side, and the center line CL of the pipe 11 is 11 The pipe 11 is attached to the mounting hole 2 so that the direction of flow of exhaust gas in the dust collection duct 1 is inclined at an inclination angle θ. In other words, the pipe 11 is attached to the mounting hole 2 formed in the outer peripheral surface 1a of the dust collection duct 1 so that the pipe 11 is inclined at θ° with respect to the direction of flow of exhaust gas in the dust collection duct 1. In this embodiment, the inclination angle θ is set to 30° to 45°.

[0019] By attaching the pipe 11 to the mounting hole 2 at an angle with respect to the exhaust gas flow direction, as shown in Fig. 1, dust 17 inside the pipe 11 can easily slide down from the pipe 11 into the dust collection duct 1 in the direction shown by arrow B, and even if rain enters the pipe 11 together with outside air from outside air intake hole 16 (described later), it flows down into the dust collection duct 1. This makes it possible to reduce the amount of dust 17 that accumulates inside the pipe 11 compared to when the pipe 11 is attached perpendicular to the exhaust gas flow direction. The reason for setting the angle of inclination θ to 30° to 45° is as follows.

[0020] The angle of repose of dust 17 is about 30°, and the angle at which dust 17 falls under its own weight is around 30°. Therefore, if the inclination angle θ is smaller than 30° (the angle of repose is larger than 30°), dust 17 easily slides down inside pipe 11. However, if the inclination angle θ is smaller than 30°, the cut length on one end 11a of pipe 11 becomes longer, and the upper side of pipe 11 approaches dust collection duct 1, making it difficult to attach pipe 11 to mounting hole 2. For this reason, the lower limit of inclination angle θ is set to 30°. On the other hand, if the inclination angle θ is larger than 45°, dust 17 will have difficulty sliding down inside pipe 11. For this reason, the upper limit of inclination angle θ is set to 45°.

[0021] 1, in the pressure measuring device 10 according to this embodiment, an outside air intake hole 16 for taking in outside air from below is formed in the center of the longitudinal direction of the piping 11. The outside air intake hole 16 is formed so as to penetrate from the outside to the inside of the piping 11. As a result, outside air is taken into the inside of the piping 11 from below the outside air intake hole 16 through the outside air intake hole 16, and the outside air flows in the direction shown by arrow C in Fig. 1 and is sucked into the dust collection duct 1. At this time, dust 17 inside the piping 11 is also sucked into the dust collection duct 1 together with the outside air, making it difficult for dust 17 to accumulate inside the piping 11.

[0022] Here, the longitudinal center of the pipe 11 refers to the range of the center L / 3 when the length L of the longest part of the pipe 11 from one end 11a to the other end 11b is divided into thirds in the longitudinal direction, as shown in Fig. 2. The outside air intake hole 16 may be formed in the range of the center L / 3 of the pipe 11. In this embodiment, the length L of the longest part of the pipe 11 from one end 11a to the other end 11b is 80 mm. The reason why the outside air intake hole 16 is formed in the longitudinal center of the piping 11 will be explained by comparing it with the pressure measuring device of the second reference example shown in Figure 4 and the pressure measuring device of the third reference example shown in Figure 5.

[0023] Fig. 4 shows a partial cross section of a pressure measuring device according to a second reference example attached to a dust collection duct. In Fig. 4, the same components as those shown in Fig. 1 are given the same reference numerals, and their description may be omitted. In a pressure measuring device 101 according to a second reference example shown in Fig. 4, an outside air intake hole 16 is formed near one end 11a on the base side in the longitudinal direction of a pipe 11. The outside air intake hole 16 is formed so as to penetrate from the outside to the inside of the pipe 11.

[0024] As a result, outside air is taken into the inside of the pipe 11 from below the outside air inlet 16 through the outside air inlet 16, and flows in the direction shown by arrow E in Figure 4 to be sucked into the dust collection duct 1. At this time, because the outside air inlet 16 is formed near one end 11a on the longitudinal base side of the pipe 11, the outside air does not reach the other end 11b on the longitudinal tip side of the pipe 11, and dust 17 accumulates on the other end 11b side. For this reason, the pressure inside the dust collection duct 1 cannot be measured accurately by the pressure gauge 15 in a short time.

[0025] 5 shows a partial cross section of a pressure measuring device according to a third reference example attached to a dust collection duct. In Fig. 5, the same components as those shown in Fig. 1 are designated by the same reference numerals, and their description may be omitted. 5, an outside air intake hole 16 is formed near the other end 11b on the longitudinal tip side of the pipe 11. The outside air intake hole 16 is formed so as to penetrate from the outside to the inside of the pipe 11.

[0026] As a result, outside air is taken into the inside of the piping 11 from below the outside air inlet 16 through the outside air inlet 16, and the outside air flows in the direction shown by arrow F in Figure 5 and is sucked into the dust collection duct 1. At this time, because the outside air inlet 16 is formed near the other end 11b on the longitudinal tip side of the piping 11, the outside air does not reach the one end 11a side of the piping 11, and dust 17 accumulates on the one end 11a side. For this reason, the pressure inside the dust collection duct 1 cannot be measured accurately by the pressure gauge 15 in a short time.

[0027] On the other hand, in the pressure measuring device 10 according to this embodiment, as shown in FIG. 1, the outside air intake hole 16 is formed in the center of the pipe 11 in the longitudinal direction. As a result, outside air is taken into the inside of the piping 11 from below the outside air inlet 16 through the outside air inlet 16, and the outside air flows in the direction shown by arrow C in Fig. 1 and is sucked into the dust collection duct 1. At this time, because the outside air inlet 16 is formed in the center of the piping 11 in the longitudinal direction, the outside air circulates throughout the entire length of the piping 11, stirring up the dust 17, which is then sucked into the dust collection duct 1 together with the outside air. This makes it difficult for the dust 17 to accumulate inside the piping 11.

[0028] Next, in the pressure measuring device 10 according to this embodiment, when the outer diameter of the piping 11 is X (mm) and the diameter of the outside air intake hole 16 is Y (mm), the outer diameter X (mm) of the piping 11 and the diameter Y (mm) of the outside air intake hole 16 are set to satisfy the following equations (1) and (2). 60.5≦X≦114.3 (1) 0.08X+2 <Y<0.51X-18 ···(2) First, the reason why the outer diameter X (mm) of the pipe 11 is specified to satisfy the formula (1) is that, as described above, in this embodiment, the pipe 11 having a pipe size of 50A (the outer diameter X of the pipe 11 is 60.5 mm) to 100A (the outer diameter X of the pipe 11 is 114.3 mm) is to be attached to the mounting hole 2.

[0029] Next, the reason why the diameter Y (mm) of the outside air intake hole 16 is specified to satisfy formula (2) will be explained with reference to Figs. 6 to 9. Fig. 6 is a graph showing the relationship between the diameter of the outside air intake hole, the pressure value (negative pressure) inside the collected dust, and the dust accumulation rate when the piping size is 50A. Fig. 7 is a graph showing the relationship between the diameter of the outside air intake hole, the pressure value (negative pressure) inside the collected dust, and the dust accumulation rate when the piping size is 80A. Fig. 8 is a graph showing the relationship between the diameter of the outside air intake hole, the pressure value (negative pressure) inside the collected dust, and the dust accumulation rate when the piping size is 100A. Fig. 9 is a graph showing the relationship between the outer diameter of the piping and the diameter of the outside air intake hole.

[0030] The size of the diameter Y (mm) of the outside air intake hole 16 needs to be determined taking into consideration two things: that forming the outside air intake hole 16 in the pipe 11 prevents fluctuations in the pressure value inside the dust collection duct 1, and that dust 17 does not accumulate inside the pipe 11. In other words, as the diameter Y (mm) of the outside air intake hole 16 is increased, fluctuations in the pressure value inside the dust collection duct 1 gradually increase, while dust 17 becomes less likely to accumulate inside the pipe 11. Conversely, as the diameter Y (mm) of the outside air intake hole 16 is decreased, fluctuations in the pressure value inside the dust collection duct 1 gradually decrease, while dust 17 becomes more likely to accumulate inside the pipe 11.

[0031] Therefore, the inventors investigated the relationship between the diameter of the outside air intake hole and the pressure value (negative pressure) and dust accumulation rate in the collected dust when the pipe size of the pipe 11 was set to 50 A, 80 A, and 100 A. The results are shown in Figures 6 to 8. When the pipe size of the pipe 11 was 50A, as shown in Fig. 6, within the range where the diameter Y (mm) of the outside air intake hole 16 was from 7.5 mm to 12.5 mm, there was no fluctuation in the pressure value and no deposition of dust 17 was observed, indicating that it was an applicable diameter.

[0032] Also, when the pipe size of the pipe 11 was 80A, as shown in Fig. 7, within the range where the diameter Y (mm) of the outside air intake hole 16 was from 10 mm to 20 mm, there was no fluctuation in the pressure value and no deposition of dust 17 was observed, indicating that it was an applicable diameter. Furthermore, when the pipe size of the pipe 11 was 100A, as shown in Fig. 8, within the range where the diameter Y (mm) of the outside air intake hole 16 was from 15 mm to 40 mm, there was no fluctuation in the pressure value and no deposition of dust 17 was observed, indicating that it was an applicable diameter. Then, considering the investigation results shown in Figs. 6 to 8, the relationship between the outer diameter of the pipe and the diameter of the outside air intake hole shown in Fig. 9 was created.

[0033] In Fig. 9, when the pipe sizes of the pipe 11 were 50A (the outer diameter X of the pipe 11 was 60.5 mm), 80A (the outer diameter X of the pipe 11 was 89.1 mm), and 100A (the outer diameter X of the pipe 11 was 114.3 mm) respectively, the maximum applicable values of the diameter Y (mm) of the outside air intake hole 16 were 12.5 mm, 20 mm, and 40 mm respectively. When these data were approximated by a regression line, it was represented by a linear function of Y = 0.5056X - 20.308.

[0034] Also, in Fig. 9, when the pipe sizes of the pipe 11 were 50A (the outer diameter X of the pipe 11 was 60.5 mm), 80A (the outer diameter X of the pipe 11 was 89.1 mm), and 100A (the outer diameter X of the pipe 11 was 114.3 mm) respectively, the minimum applicable values of the diameter Y (mm) of the outside air intake hole 16 were 7.5 mm, 10 mm, and 15 mm respectively. When these data were approximated by a regression line, it was represented by a linear function of Y = 0.1382X - 1.3274. From the results shown in this Fig. 9, if the diameter Y (mm) of the outside air intake hole 16 satisfies the formula of 0.1382X - 1.3274 < Y < 0.5056X - 20.308, it can be an applicable diameter.

[0035] However, when the pipe size of the pipe 11 is 50A (the outer diameter X of the pipe 11 is 60.5mm), the applicable maximum value (12.5mm) of the diameter Y (mm) of the outside air intake hole 16 is set to, and when the pipe size of the pipe 11 is 100A (the outer diameter X of the pipe 11 is 114.3mm), the applicable maximum value (40mm) of the diameter Y (mm) of the outside air intake hole 16 is set to, Y>0.5056X-20.308, which does not satisfy the above formula. Furthermore, when the pipe size of pipe 11 is 80A (the outer diameter X of pipe 11 is 89.1 mm), the applicable minimum value (10 mm) of the diameter Y (mm) of outside air intake hole 16 becomes X-1.3274>Y, which does not satisfy the above formula.

[0036] Therefore, in order to make all applicable maximum and minimum values ​​of the diameter Y (mm) of the outside air intake hole 16 applicable when the pipe size of the pipe 11 is 50A, 80A, and 100A, the diameter Y (mm) of the outside air intake hole 16 is set to satisfy the above-mentioned equation (2). In the above-mentioned formula (2), when the diameter Y (mm) of the outside air intake hole 16 is Y≧0.51X−18, the diameter of the outside air intake hole 16 is too large, resulting in large fluctuations in the pressure value inside the dust collection duct 1. On the other hand, when Y≦0.08X+2 or less, the diameter of the outside air intake hole 16 is too small, causing dust 17 inside the piping 11 to accumulate inside the piping 11.

[0037] In addition, factors that determine the applicable range of the diameter Y (mm) of the outside air intake hole 16 include the diameter Y (mm) of the outside air intake hole 16 and the outer diameter X (mm) of the pipe 11, which appear in formula (2), as well as the outer diameter DD of the dust collection duct 1 and the wind speed inside the dust collection duct 1. The outer diameter DD of the dust collection duct 1 is excluded because the purpose of the present invention is to prevent the inside of the pipe 11, which is the pressure intake, from being clogged with dust 17. Furthermore, regarding the wind speed inside the dust collection duct 1, it is preferable that the average wind speed per hour be 10 m / s or more when the dust collector (not shown) is operating. This is because if the average wind speed is less than 10 m / s, it becomes difficult to collect dust inside the pipe 11.

[0038] Next, the attachment of the pressure gauge 15 to the other end 11b of the pipe 11 will be described with reference to FIGS. A threaded portion (male threaded portion) 11d is formed on the outer peripheral surface 11c of the other end 11b of the pipe 11. The pressure gauge 15 is attached to a socket 12 that is screwed onto the threaded portion 11d of the pipe 11 via a hose nipple 13 and a pressure hose 14. The socket 12 is formed with a recess 12a that receives the other end 11b of the pipe 11, and the inner peripheral surface of the recess 12a is formed with a threaded portion (female threaded portion) 12b that is screwed onto the threaded portion 11d of the pipe 11.

[0039] In this way, before forming the threaded portion 11d on the outer peripheral surface 11c of the other end 11b of the pipe 11, a female threaded portion is formed on the inner periphery of the other end 11b of the pipe 11, and an LA coupling is screwed onto this female threaded portion. Then, a male threaded portion is formed on this LA coupling, and a pressure gauge 15 is attached to a socket 12 screwed onto the male threaded portion of the LA coupling via a hose nipple 13 and a pressure hose 14.

[0040] In this embodiment, a threaded portion (male threaded portion) 11d is formed on the outer periphery of the other end 11b of the pipe 11, and a pressure gauge 15 is attached to a socket 12 that is screwed onto the threaded portion 11d of the pipe 11 via a hose nipple 13 and a pressure hose 14. This makes it possible to connect the socket 12 directly to the other end 11b of the pipe 11 without the LA coupling, and the length of the portion where dust 17 accumulates is reduced by the length of the LA coupling. This avoids the risk of dust 17 accumulating at the LA coupling on the other end 11b of the pipe 11 and making it impossible to collect the dust, and increases the efficiency of collecting the dust 17.

[0041] Thus, according to the pressure measuring device 10 of this embodiment, the pipe 11 is attached to the mounting hole 2 formed on the outer surface 1a of the dust collection duct 1 at an angle of 30° to 45° with respect to the flow direction of the exhaust gas within the dust collection duct 1 (the direction indicated by the arrow Ad). This allows dust 17 inside the pipe 11 to slide down more easily from the pipe 11 into the dust collection duct 1, and even if rain enters the pipe 11 together with outside air from outside air intake hole 16 (described later), it will flow down into the dust collection duct 1. This makes it possible to reduce the amount of dust 17 that accumulates inside the pipe 11 compared to when the pipe 11 is installed perpendicular to the direction of exhaust air flow.

[0042] An outside air intake hole 16 is formed in the center of the pipe 11 in the longitudinal direction to take in outside air from below. As a result, outside air is taken into the inside of the pipe 11 from below the outside air intake hole 16 through the outside air intake hole 16, and the outside air is sucked into the dust collection duct 1. At this time, because the outside air intake hole 16 is formed in the center of the pipe 11 in the longitudinal direction, the outside air circulates throughout the entire length of the pipe 11, stirring up the dust 17, and the dust 17 is sucked into the dust collection duct 1 together with the outside air. This makes it difficult for the dust 17 to accumulate inside the pipe 11.

[0043] The outer diameter X (mm) of the pipe 11 and the diameter Y (mm) of the outside air intake hole 16 are set so as to satisfy the above-mentioned formulas (1) and (2). As a result, when the outer diameter X (mm) of the pipe 11 is 60.5 mm to 114.3 mm, the diameter Y (mm) of the outside air intake hole 16 can be set appropriately, and the pressure value inside the dust collection duct 1 can be prevented from fluctuating, thereby avoiding the risk of dust 17 inside the pipe 11 accumulating inside the pipe 11.

[0044] Therefore, the pressure measuring device 10 according to this embodiment does not require equipment such as a compressed air supply source, is easy to maintain, and has a low manufacturing cost, and can appropriately prevent the inside of the pipe 11 from becoming clogged with dust 17, and can accurately measure the pressure inside the dust collection duct 1 using the pressure gauge 15.

[0045] Furthermore, according to the pressure measuring device 10 of this embodiment, a threaded portion (male threaded portion) 11d is formed on the outer periphery of the other end 11b of the pipe 11, and the pressure gauge 15 is attached to a socket 12 that is screwed onto the threaded portion 11d of the pipe 11. This makes it possible to connect the socket 12 directly to the other end 11b of the pipe 11 without the LA coupling, and the length of the portion on which dust 17 accumulates is reduced by the length of the LA coupling. This avoids the risk that dust 17 will accumulate at the LA coupling on the other end 11b side of the pipe 11 and become unable to be collected, and allows the efficiency of collecting dust 17 to be increased.

[0046] Although the embodiment of the present invention has been described above, the present invention is not limited to this and various modifications and improvements can be made. For example, the length L of the longest portion of the pipe 11 from one end 11a to the other end 11b is not limited to 80 mm. Alternatively, instead of forming a threaded portion 11d on the outer peripheral surface 11c of the other end 11b of the pipe 11, a female threaded portion may be formed on the inner periphery of the other end 11b of the pipe 11, and the LA coupling may be screwed onto this female threaded portion, thereby attaching the pressure gauge 15 to the other end 11b side of the pipe 11. Furthermore, the flow direction of the exhaust gas in the dust collection duct 1 is not limited to the bottom-to-top direction, but may be the top-to-bottom direction, a diagonal direction relative to the top-to-bottom direction, or a horizontal direction. [Explanation of symbols]

[0047] 1 Dust collection duct 1a Outer surface 2 mounting holes 10 Pressure measuring device 11 Piping 11a one end 11b other end 11c Outer surface 11d Threaded portion (male threaded portion) 12 sockets 12a Recess 12b Threaded portion (female threaded portion) 13 Hose nipple 14 Pressure Hose 15 Pressure gauge 16 External hole extraction 17 Dust

Claims

1. A pressure measuring device having a pipe attached at one end to a mounting hole formed on an outer peripheral surface of a dust collection duct that collects dust by circulating exhaust gas containing dust, and having attached at the other end a pressure gauge that measures the pressure inside the dust collection duct, The piping is attached to the mounting hole at an angle of 30° to 45° with respect to the direction of exhaust air flow in the dust collection duct, and an outside air intake hole is formed in the center of the longitudinal direction of the piping to take in outside air from below, A pressure measuring device characterized in that an outer diameter X (mm) of the piping and a diameter Y (mm) of the outside air intake hole are set to satisfy the following equations (1) and (2): 60.5≦X≦114.3 (1) 0.08X+2<Y<0.51X-18...(2)

2. 2. The pressure measuring device according to claim 1, wherein a threaded portion is formed on an outer peripheral surface of the other end of the pipe, and the pressure gauge is attached to a socket that is screwed onto the threaded portion of the pipe.

Images