JP4884060B2 - Pressure detection tube - Google Patents

Description

  The present invention relates to a pressure detection pipe that transmits a pressure in a flue used in a power plant or the like to a pressure detector.

  FIG. 5 is a diagram showing a schematic system of a desulfurization apparatus 1 of a conventional general thermal power plant. The combustion exhaust gas of the boiler sent via the desulfurization blower 2 is heat-exchanged by the gas gas heater 3 and lowered in temperature, and then sent to the dust removal tower 4 where the dust contained in the combustion exhaust gas is removed. The gradually exhausted combustion exhaust gas is heated by the gas gas heater 3 after the sulfur oxide contained in the combustion exhaust gas is removed by the absorption tower 5, and is discharged from the chimney 7 through the induction fan 6. Each of the above devices and equipment is connected by a flue 8.

  The combustion gas in a boiler furnace such as a thermal power plant has a temperature of several hundreds of degrees Celsius and contains harmful components such as nitrogen oxide (NOx) and sulfur oxide (SOx). There should be no leaks outside the furnace. For this reason, the combustion gas is sucked by the induction fan 6 installed at the inlet of the chimney 7, and the entire flue from the boiler to the inlet of the induction fan 6 is maintained at a negative pressure of several tens of millimeters to hundreds of millimeters of water. The combustion gas is prevented from leaking out of the system. Furthermore, the pressure in the furnace of the boiler is constantly monitored, and when the pressure in the furnace changes to a positive pressure, the plant is brought to an emergency stop.

  The pressure of each part is an important parameter for not only preventing gas leakage but also detecting abnormalities in the plant and knowing the state of the equipment, and pressure measurement is indispensable for boiler operation control. For this reason, pressure detectors 10 and 11 are provided in the flue 8 at the inlet and outlet of the desulfurization blower 2 in order to check whether the desulfurization blower 2 is operating normally. By measuring the pressure in this portion, it is possible to monitor the deterioration of the blowing performance, the change in the amount of combustion gas, or the presence or absence of blockage. Similarly, differential pressure detectors 13 and 14 for measuring the differential pressure across the orifice flow meter 12 and the gas gas heater 3 are provided. In addition, pressure detectors 15 and 16, 17, 17, 18, and 19 for detecting pressure are provided at various locations of the flue 8. As described above, even in the desulfurization apparatus 1, many pressure detectors and differential pressure detectors are provided. In a large-scale thermal power plant, 100 or more pressure detectors are provided.

  The pressure in the flue is performed by attaching a pressure detector to a pressure detection tube attached to the wall surface of the flue 8. FIG. 6 is a longitudinal sectional view showing a state in which the conventional pressure detection tube 20 is attached to the flue wall 41. FIG. 6 is a diagram for explaining the structure, and is not necessarily drawn to the same scale. The pressure detection tube 20 is composed of a Y-shaped tube 21 having a Y-shape, and is fixed to the flue wall 41 via a contact plate 22. The Y-shaped tube 21 includes an oblique tube 23, a blow nozzle 24, a vertical tube 25, and a pressure conduit 26. The pressure conduit 26 is connected to a pressure detector or a differential pressure detector (not shown). Anticorrosion coatings 42, 43, and 44 are provided on the inner wall of the flue wall 41, the inner wall of the oblique tube 23, and the vertical tube 25 to prevent corrosion by corrosive gas.

Since the conventional pressure detection tube 20 is fixed to the flue wall 41 by welding via the contact plate 22, the anticorrosion coating 42 on the flue wall in the vicinity of the welded portion 9 is easily damaged by a thermal effect. When the anticorrosion coating 42 is damaged, the inner wall of the flue is corroded, and therefore, the anticorrosion coating needs to be separately applied to the portion where the anticorrosion coating is damaged. Also, the pressure detection tube 20 is inevitably deteriorated due to the passage of operation time, and the pressure detection tube 20 needs to be periodically repaired or replaced entirely. In addition, although the applicant investigated the prior document, the prior art document which should be described was not found.

  Since the conventional pressure detection tube 20 is fixed to the flue wall 41 by welding via the contact plate 22, the inspection and repair of the welded portion 9 where the anticorrosion coating 42 is easily damaged is structurally performed from the inside of the flue. You can't do it without it. When exchanging the pressure detection tube 20, using a gas torch or the like, a part of the flue wall 41 is cut off from the outside together with the pressure detection tube 20, and the contact plate 22 is newly welded to the opening, A new pressure detection tube 20 is welded and fixed to the contact plate 22. After that, an operator enters the inside of the flue 8 and finishes with anticorrosion coating from the inside.

  In order for the worker to enter the inside of the flue 8, after the plant is shut down, it is necessary to wait for the flue to be replaced with air and further cooled. In the case of a large plant, the heat capacity is large and a cooling period of several tens of hours to several days is required. Depending on the structure and size of the flue, and the position of the pressure detection pipe, it is necessary to build a large scaffold, and it takes a lot of time and labor to carry in and assemble the scaffold member, and to dismantle and carry out the scaffold after completion of the work. In addition, when working in a flue, a plurality of workers are required including a safety monitor and a contact person for safety. If the above-mentioned maintenance inspection, repair, and replacement can be performed from the outside of the flue, these expenses can be reduced and the work can be performed safely.

  An object of the present invention is to provide a pressure detection tube that is low in maintenance inspection cost and that can perform maintenance inspection work safely.

The pressure detection pipe according to claim 1, wherein an opening is provided in a wall of the flue whose inner wall is coated with anticorrosion, and the pressure detection pipe is attached to the opening and transmits the pressure in the flue to the pressure detector,
A Y-tube communicating with the gas in the flue and having an anti-corrosive coating on the inner wall;
The smoke which has a convex part which fits into the opening, and a flange part provided at the periphery of the convex part, supports the Y-shaped tube, and detachably fixes the Y-shaped tube to the flue wall A portion in contact with the gas in the road is provided with a Y-shaped tube support coated with anticorrosion,
The size of the opening is a size capable of applying an anticorrosion coating to the inner wall of the flue around the opening from at least the outside of the flue,
The Y-tube support has a shape in which, when the Y-tube support is fixed to the flue wall via a gasket, the end surface of the convex portion is flush with the inner wall surface of the flue. It is characterized by that.

The pressure detection tube according to claim 2, wherein the Y-shaped tube support is further coated with an anticorrosion coating on a portion that contacts the gasket,
The outer wall of the flue around the opening is characterized in that a portion in contact with the gas in the flue and a portion in contact with the gasket are anticorrosive coated.

  The pressure detection pipe according to claim 3 is characterized in that the Y-tube support is fixed to the flue wall with a stud bolt.

The pressure detection pipe according to claim 4 is a pressure detection pipe which is provided with an opening on a wall surface of a flue whose inner wall is anticorrosive coated, and is attached to the opening to transmit the pressure in the flue to a pressure detector.
A Y-tube communicating with the gas in the flue and having an anti-corrosive coating on the inner wall;
The smoke which has a convex part which fits into the opening, and a flange part provided at the periphery of the convex part, supports the Y-shaped tube, and detachably fixes the Y-shaped tube to the flue wall A portion in contact with the gas in the road is provided with a Y-shaped tube support coated with anticorrosion,
The size of the opening is a size capable of applying an anticorrosion coating to the inner wall of the flue around the opening from at least the outside of the flue,
When the Y-tube support is fixed via a gasket to a flange mounting seat attached to the flue outer wall having the same peripheral edge as the peripheral edge of the opening, the end face of the convex part is It has the shape which becomes the same plane without a level | step difference with the inner wall surface of a flue.

  The pressure detection pipe according to claim 5 is characterized in that the flange mounting seat has an anticorrosive coating on a surface in contact with the gas in the flue and a surface in contact with the gasket.

  According to the first aspect of the present invention, the pressure detection tube is provided with an opening in the wall surface of the flue whose inner wall is anticorrosive coated, and the pressure detection tube is attached to the opening to transmit the pressure in the flue to the pressure detector. And having a Y-shaped tube that communicates with the gas in the flue and has an inner wall coated with anticorrosion, a convex portion that fits into the opening, and a flange portion that is provided at the periphery of the convex portion. And a Y-tube support that is anti-corrosive coated on the gas in the flue for removably fixing the Y-tube to the flue wall, and the size of the opening is at least outside the flue From the outside of the flue, the pressure detection pipe can be attached and detached, and the anticorrosion coating can be performed from the outside of the flue. . Since it is not necessary for an operator to enter the flue for repair or replacement, it is necessary to wait for the cooling time of the plant, which has been indispensable for repairing or replacing the pressure detection tube, and to carry the scaffold member into the flue after cooling. There is no need for assembly, dismantling of the scaffold after completion of work, safety management work associated with the work in the flue, and the time and labor required for replacing the pressure detection pipe can be greatly reduced. Furthermore, it is possible to safely replace the pressure detection tube.

  Further, the Y-tube support has a shape in which when the Y-tube support is fixed to the flue wall via a gasket, the end surface of the convex portion is flush with the inner wall surface of the flue without any step. It is possible to accurately measure the pressure in the flue without causing disturbance in the flow of gas flowing through the passage. Furthermore, local corrosion due to ash accumulation can be prevented in advance. As a result, it is possible to extend the time for repairing and replacing the pressure detection tube, and to reduce the maintenance cost of the pressure detection tube.

  According to the second aspect of the present invention, the portion of the Y-tube support that contacts the gasket is further anticorrosive coated, and the outer flue wall around the opening is in contact with the gas in the flue and the gasket. Since the contact portion is coated with anticorrosion, corrosion of the flange and the flue wall can be effectively prevented. Thereby, it becomes possible to extend the repair and replacement period of the pressure detection tube, and to further reduce the maintenance cost.

  According to the third aspect of the present invention, since the Y-shaped tube support is fixed to the flue wall with the stud bolt, the pressure detection tube can be easily repaired and replaced. As a result, it is possible to further reduce the time and labor for repairing and replacing the pressure detection tube.

  According to the fourth aspect of the present invention, the pressure detection pipe is provided on the Y-shaped pipe communicating with the gas in the flue and having the inner wall coated with anticorrosion, the convex part fitted into the opening, and the peripheral edge of the convex part. A Y-tube support having a flange portion, a Y-tube support for supporting the Y-tube, and a portion in contact with the gas in the flue for removably fixing the Y-tube to the flue wall; The size of the opening is such that the anticorrosion coating can be applied to the inner wall of the flue around the opening from the outside of the flue, and the Y-tube support is the same size as the periphery of the opening. When the flange is fixed to a flange mounting seat attached to the outer wall of the flue having a peripheral edge with a gasket, the end surface of the convex part has a shape that is flush with the inner wall surface of the flue, so it is easy to Maintenance and replacement of the pressure detection tube can be performed. In addition, because it has a flange mounting seat, even if the studs cannot be mounted directly on the flue wall due to strength or structural reasons, the pressure detection tube is detachably fixed to the flue wall via the flange mounting seat. Therefore, the present invention can be applied to various flues.

  According to the fifth aspect of the present invention, since the flange contact seat is coated with the anticorrosion coating on the surface in contact with the gas in the flue and the surface in contact with the gasket, the repair and replacement period of the pressure detection tube can be extended. This makes it possible to further reduce maintenance costs.

  FIG. 1 is a longitudinal sectional view of a pressure detection tube 30 as a first embodiment of the present invention. FIG. 2 is an enlarged view of a portion II in FIG. 1 and 2 are diagrams for explaining a schematic structure, and are not necessarily drawn to the same scale. The same members as those in FIG. 6 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The pressure detection pipe 30 of the present invention is provided with an opening 45 in the flue wall 41 and is attached to the opening 45 to transmit the pressure of the flue 8 to a pressure detector or a differential pressure detector not shown through the pressure conduit 26. And includes a Y-tube 21 and a Y-tube support 32 attached to one end of the Y-tube 21. The Y-shaped tube 21 includes an oblique tube 23 attached obliquely to the flue wall 41, a blow nozzle 24 attached to one end of the oblique tube 23, and a vertical provided so as to branch in the middle of the oblique tube 23. A pipe 25 and a pressure conduit 26 attached to one end of the vertical pipe 25 are included.

  The slant pipe 23 communicates with the flue 8 and plays a role of transmitting pressure to the pressure conduit 26 through the vertical pipe 25. The slant pipe 23 prevents the accumulation of soot and dust that impedes pressure transmission as much as possible. The wall 41 is attached obliquely. The blow nozzle 24 is for cleaning the inside of the oblique tube 23. The gas in the flue 8 contains a very small amount of soot and dust, although in a very small amount. Finer dust has a higher adhesion and cannot be completely prevented by the inclined structure alone. Therefore, high-pressure air is periodically ejected from the blow nozzle 24 to remove the dust adhering to the oblique tube 23. The vertical pipe 25 is also vertically attached to the oblique pipe 23 in order to prevent soot accumulation, and a pressure conduit 26 attached to one end of the vertical pipe 25 is connected to a pressure detector (not shown) in the flue. Transmits pressure. Anti-corrosion coatings 43 and 44 are provided on the inner walls of the oblique tube 23 and the vertical tube 25 to prevent corrosion. Note that the Y-shaped tube 21 has basically the same configuration as the conventional Y-shaped tube 21.

  A Y-tube support 32 for attaching the Y-tube 21 to the flue wall 41 is attached to the other end of the oblique tube 23. The Y-shaped tube support body 32 includes a central projecting portion 33 and a flange portion 34 provided on the periphery of the projecting portion 33. A through-hole is formed in the vicinity of the central portion of the convex portion 33, and the gas in the flue 8 is communicated with the oblique tube 23 by fixing the oblique tube 23 to the through-hole. The protrusion 33 is fitted into the opening 45 when the pressure detection tube 30 is attached to the opening 45 of the flue wall 41 as will be described later, and the height of the protrusion 33 is such that the end surface 39 of the flue wall 41 The height is the same plane as the inner surface 47 without any step. Thereby, even if the pressure detection tube 30 is attached to the flue wall 41, the gas flow flowing in the flue 8 is not disturbed, and the pressure in the flue 8 can be measured accurately. . The flange portion 34 includes a bolt hole (not shown) for mounting. Since this pressure detection tube 30 is attached to and used in the opening 45 provided in the flue wall 41, the size of the flange portion 34 is a size capable of closing the opening 45. Further, the Y-tube support 32 is provided with an anticorrosion coating on the portion 35 in contact with the gas in the flue 8 in order to prevent corrosion.

  The pressure detection tube 30 is attached to the opening 45 of the flue wall 41 and used in the following manner. The flue 8 has a rectangular cross section, and an opening 45 is provided in the vertical wall surface 41 of the flue 8, and the pressure detection tube 30 is attached so as to close the opening 45. The size of the opening 45 is such that the anticorrosion coating 42 can be applied to the inner wall of the flue around the opening 45 from at least the outside of the flue 8. A stud 50 for fixing the Y-tube support 32 is attached to the flue wall around the opening 45. Thereby, the pressure detection tube 30 can be detachably fixed to the flue wall 41. The flange portion 34 is fixed to the flue wall 41 via the gasket 51. The type of the gasket 51 used here is not particularly limited as long as it has corrosion resistance and heat resistance to the gas flowing through the flue 8 and has a structure in which the gas in the flue does not leak to the outside.

  When the Y-tube support 32 is fixed to the flue wall 41 via the gasket 51, the portion 35 that comes into contact with the gas in the flue 8, the portion 36 that comes into contact with the gasket 51, and the gasket 51 are also coated with an anticorrosive coating. After applying. Further, the outer wall of the flue around the opening and the portion 37 that contacts the gas in the flue and the portion 38 that contacts the gasket 51 are also coated with anticorrosion. Thereby, corrosion of the Y-shaped tube support body 32 and the flue wall 41 can be effectively suppressed. Since the cross-sectional shape of the Y-tube support body 32 is convex, when the pressure detection tube 30 is attached to the flue wall 41, the convex portion 33 is fitted into the opening 45, and the end surface of the convex portion 33 is further inserted. 39 is flush with the inner surface 47 of the flue wall.

  As described above, the pressure detection device 30 is fixed to the flue wall 41 through the stud bolt 50, the gasket 51, and the nut 52, and can be easily attached and detached from the outside of the flue, so that it can be inspected, maintained, repaired, or replaced. There is no need for workers to enter the flue. When the anticorrosion coating 35, 36, 43, 44 applied to the pressure detection pipe 30 is peeled off or deteriorated and needs to be repaired, the pressure detection pipe 30 is removed and transferred to a safe and workable place for repair. be able to. Further, the opening 45 formed in the flue wall 41 is of a size that allows the anticorrosion coating to be applied to the inner wall 47 of the flue 8 around the opening 45 from at least the outside of the flue 8. For the inner wall 47 of the flue 8 around 45, the pressure detection tube 30 can be removed and the anticorrosion coating 42 can be applied from the outside of the flue 8.

  Since the anticorrosion coating 42 can be applied to the flue inner wall 47 from the outside of the flue 8, the cooling operation of the flue 8 is unnecessary, and the repair work can be performed within a short time after the plant is stopped. Conventionally, it is not necessary to carry in and assemble the scaffold member into the flue and to dismantle and carry out the scaffold after completion of the work, which has been necessary when repairing the pressure detection pipe. In addition, since safety management work associated with work in the flue is not necessary, not only the construction period and cost can be greatly reduced, but also repair work can be performed safely.

  Furthermore, since the convex end surface 39 of the Y-shaped tube support body 32 is attached so as to be flush with the inner surface 47 of the flue wall, the following effects can be obtained. The area around the flue wall 41 to which the projections such as the oblique tube 23 are attached has more heat radiation than the flat flue wall on which nothing is attached due to the heat radiation effect (fin effect) by the projections. Since it is easy to cool, the corrosive components are likely to condense. In addition to such an adverse condition, if there is a step on the flue inner wall 47, ash accumulates and locally inhibits the flow of combustion exhaust gas, further lowering the temperature and causing low temperature corrosion due to condensation. By eliminating the step as shown in the present invention, ash accumulation can be prevented and low-temperature corrosion can be prevented. As a result, the inspection, repair, and replacement intervals can be extended, which helps reduce operating costs.

  FIG. 3 is a longitudinal sectional view of a pressure detection tube 60 as a second embodiment of the present invention. FIG. 4 is an enlarged view of a portion IV in FIG. 3 and 4 are diagrams for explaining a schematic structure, and are not necessarily drawn to the same scale. The same members as those in FIGS. 1, 2 and 6 are denoted by the same reference numerals, and detailed description thereof is omitted.

  3 has the same configuration as the pressure detection tube 30 shown in FIGS. 1 and 2, but the height of the convex portion 33 of the Y-shaped tube support 32 is compared with the height of the convex portion 33 shown in FIG. And expensive. This is because the pressure detection tube 60 is attached via the flange attachment seat 61 when being fixed to the flue wall 41. Even when the pressure detection tube 60 is fixed to the flue wall via the flange mounting seat 61, the end surface 39 of the convex portion 33 of the Y-tube support 32 is flush with the inner wall 47 of the flue wall without any step. It is for mounting so that it becomes. When the pressure detection pipe cannot be fixed to the flue wall 41 via the stud bolt 50 due to structural or strength reasons, that is, when the fixing method shown in FIGS. 1 and 2 cannot be adopted. The pressure detection tube can be attached via the flange mounting seat 61.

  The flange mounting seat 61 is for fixing the pressure detection tube 60 to the flue wall 41, has a strong flange 62 on one side, and the flange 34 of the Y-tube support 32 on the opposite surface. The flange 63 having a bolt hole corresponding to the bolt hole is provided, and the two flanges 62 and 63 are connected by a rectangular or circular frame 64. The size of the inside of the frame 64 is the same as the size of the opening 45, and the flange portion 34 of the Y-tube support 32 is fixed to the flange portion 63 by fixing the flange portion 62 to the flue outer wall. ing.

  When the pressure detection tube 60 is attached to the flue wall 41, the flange attachment seat 61 is disposed outside the flue wall so that no step is formed with the opening 45 so as to surround the opening 45 provided in the flue wall 41. And fixed to the flange mounting seat 61 with a bolt 50 and a nut 52 via a gasket 51. Similarly to the Y-tube support body 32, the flange mounting seat 61 also has a portion 65 in contact with the gasket 50 and a portion 66 in contact with the gas in the flue, which are subjected to anticorrosion coating. Install.

  In the second embodiment, the pressure detection tube is easily repaired and replaced, and the first embodiment having the effect that these can be performed in a short time and safely, the strength of the flue wall is low, It was devised so that it can be applied to the flue where it is difficult to install the stud bolt for structural reasons. Thereby, the pressure detection pipe | tube of this invention is applicable to various flue. In the second embodiment, the bolt 51 and the nut 52 are used as means for fixing the pressure detection tube 60 to the flange mounting seat 61, but other methods, for example, one end of the flange portion 34 is hinged (illustrated). The same effect can be obtained by connecting to the flange mounting seat 61 and fixing the other end with a one-touch type clamp (not shown).

It is a longitudinal cross-sectional view of the pressure detection pipe | tube 30 as 1st embodiment of this invention. It is the enlarged view which expanded and showed the II section of FIG. It is a vertical side view of the pressure detection pipe | tube 60 as 2nd embodiment of this invention. It is the enlarged view which expanded and showed the IV section of FIG. It is a systematic diagram which shows schematic structure of the flue gas desulfurization apparatus which is a prior art. It is a longitudinal cross-sectional view which shows the state in which the conventional pressure detection pipe | tube 20 was attached to the flue wall 41. FIG.

Explanation of symbols

8 Flue 21 Y-tube 30 Pressure detection tube 32 Y-tube support 33 Convex portion 34 Flange portion 35 Portion of Y-tube support in contact with flue gas 36 Portion of Y-tube support in contact with gasket 37 Portion of flue outer wall in contact with flue gas 38 Portion of flue outer wall in contact with gasket 39 Convex end surface 41 Flue wall 45 Opening portion 47 Inner wall surface of flue wall 50 Stud bolt 51 Gasket 61 Flange mounting seat 65 Flange Part in contact with gasket of mounting seat 66 Part in contact with flue gas of flange mounting seat

Claims (5)

A pressure detection pipe which is provided with an opening on a wall of a flue whose inner wall is anticorrosive coated, and which is attached to the opening and transmits the pressure in the flue to a pressure detector;
A Y-tube communicating with the gas in the flue and having an anti-corrosive coating on the inner wall;
The smoke which has a convex part which fits into the opening, and a flange part provided at the periphery of the convex part, supports the Y-shaped tube, and detachably fixes the Y-shaped tube to the flue wall A portion in contact with the gas in the road is provided with a Y-shaped tube support coated with anticorrosion,
The size of the opening is a size capable of applying an anticorrosion coating to the inner wall of the flue around the opening from at least the outside of the flue,
The Y-tube support has a shape in which, when the Y-tube support is fixed to the flue wall via a gasket, the end surface of the convex portion is flush with the inner wall surface of the flue. A pressure detection tube characterized by that. The Y-tube support is further coated with an anticorrosion coating on the portion that contacts the gasket,
2. The pressure detection pipe according to claim 1, wherein the outer wall of the flue around the opening is coated with an anticorrosion coating on a portion that contacts the gas in the flue and a portion that contacts the gasket.   The pressure detection tube according to claim 1 or 2, wherein the Y-shaped tube support is fixed to the flue wall by a stud bolt. A pressure detection pipe which is provided with an opening on a wall of a flue whose inner wall is anticorrosive coated, and which is attached to the opening and transmits the pressure in the flue to a pressure detector;
A Y-tube communicating with the gas in the flue and having an anti-corrosive coating on the inner wall;
The smoke which has a convex part which fits into the opening, and a flange part provided at the periphery of the convex part, supports the Y-shaped tube, and detachably fixes the Y-shaped tube to the flue wall A portion in contact with the gas in the road is provided with a Y-shaped tube support coated with anticorrosion,
The size of the opening is a size capable of applying an anticorrosion coating to the inner wall of the flue around the opening from at least the outside of the flue,
When the Y-tube support is fixed via a gasket to a flange mounting seat attached to the flue outer wall having the same peripheral edge as the peripheral edge of the opening, the end face of the convex part is A pressure detection tube characterized by having a shape that is flush with the inner wall surface of the flue. The pressure detection pipe according to claim 4, wherein the flange mounting seat has an anticorrosive coating on a surface in contact with the gas in the flue and a surface in contact with the gasket.

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