JP2020076544A - Leakage inspection method of condenser - Google Patents

Abstract

To carry out the leakage inspection of a cooling pipe of a condenser.SOLUTION: A leakage inspection of a condensor 100 having a pair of pipe plates 112 and 113, and a plurality of cooling pipes 111 joined to the pipe plates at both ends, is carried out by sealing a cooling water inflow chamber 120 and a cooling water outflow chamber 130 communicating to the inside of the cooling pipes 111, adhering a leakage inspection agent to a joint portion the cooling pipes 111 and the pipe plates 112 and 113 on the cooling water inflow chamber 120 side and the cooling water outflow chamber 130 side, and decompressing the cooling water inflow chamber 120 side and the cooling water outflow chamber 130, and adhering a reaction liquid of the leakage inspection agent on the external side of the cooling pipes 111.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a leakage inspection method for a condenser that cools and condenses steam discharged from a steam turbine or the like.

  As a method of inspecting the condenser cooling pipe for leaks, both ends are open, and the cooling pipe supported by the pipe plate is abutted on both sides of the cooling pipe plate to close the opening. An equal pressure between the inner cap that seals the inner cap, the outer cap that covers the outer periphery of the inner cap, the space formed by the outer cap and the inner cap, and the cooling pipe that is sealed by the inner cap. The pressure inside the space formed by the outer cap and the inner cap at a constant pressure, the inside of the cooling pipe sealed by the inner cap, the outside cap and the inside A technique of performing a leak test using a differential pressure gauge that measures a differential pressure between the cap and a space formed by the cap is known (for example, see Patent Document 1).

JP, 2000-146459, A

  However, in the method using the outer cap and the inner cap as described above, since the structure of the caps installed at both ends of the water cooling pipe is complicated and one cooling pipe is inspected one by one, many cooling pipes are inspected. It takes a lot of time and labor to inspect for leakage.

  The present invention has been made in view of the above points, and an object of the present invention is to make it possible to perform a leak inspection of a cooling pipe of a condenser in a short time.

To achieve the above objectives,
The present invention is
A leakage inspection method for a condenser having a pair of tube sheets, a plurality of cooling tubes having both ends joined to the tube sheet, and a body for housing the cooling tubes,
A cooling water inflow chamber communicating with the inside of the cooling pipe, and a sealing step of bringing the cooling water outflow chamber into a sealed state,
A leakage inspection agent adhering step of adhering a leakage inspection agent to the joint between the cooling pipe and the tube plate on the cooling water inflow chamber side and the cooling water outflow chamber side;
A decompression step of decompressing the cooling water inflow chamber and the cooling water outflow chamber,
A reaction liquid adhering step of adhering a reaction liquid of the leakage inspection agent to a joint between the cooling pipe and the tube sheet on the body side of the cooling pipe,
It is characterized by having.

  This makes it easy to visually confirm the leakage of the reaction liquid to the cooling water inflow chamber or the cooling water outflow chamber to which the leakage inspection agent has adhered, so it is possible to check the presence / absence of leakage in many cooling pipes and to check with high reliability. can do.

  According to the present invention, the leakage inspection of the condenser cooling pipe can be performed in a short time.

It is a perspective view showing a schematic structure of a condenser. It is explanatory drawing which shows the leak inspection method of a condenser typically. It is a flowchart which shows the leak inspection method of a condenser.

  Hereinafter, as an embodiment of the present invention, a leak inspection of a condenser for condensing steam from a steam turbine or the like will be described.

(Schematic configuration of the condenser 100)
As shown in FIG. 1 and FIG. 2, the condenser 100 is provided with a steam inflow part 110a into which steam from a steam turbine flows in an upper part of a body 110 and a condensate outflow part 110b in which a condensed condensate flows out to a lower part. In addition, a large number of cooling pipes 111 are provided inside in parallel with each other. Both ends of the cooling pipe 111 are joined to a pair of tube plates 112 and 113. More specifically, for example, the end portion of the cooling pipe 111 is inserted into a through hole formed in the tube sheets 112 and 113, and the cooling pipe 111 is joined by being expanded from the inner surface side by a tube expander or the like. There is. In particular, for example, when the tube sheets 112 and 113 are made of steel and the cooling tube 111 is a brass tube or a white copper tube, it is difficult to perform seal welding to improve airtightness. By forming a circumferential group on the inner peripheral surface and expanding the cooling pipe 111 as described above, airtightness is improved.

  The inside of the cooling pipe 111 communicates with a cooling water inflow chamber 120 and a cooling water outflow chamber 130 (channels) provided on both sides of the tube plates 112 and 113. A cooling water inflow pipe 122 or a cooling water outflow pipe 132 is connected to the cooling water inflow chamber 120 and the cooling water outflow chamber 130, respectively, and, for example, seawater flows through the cooling water inflow pipe 122, the cooling pipe 111, and the cooling water outflow pipe 132. It is supposed to be distributed through. Each of the cooling water inflow chamber 120 and the cooling water outflow chamber 130 is provided with a manhole (not shown) through which a person can pass for inspection or the like. The manhole cover 121 and the manhole cover 131 can be opened or closed. ing. The cooling water inflow chamber 120 and the cooling water outflow chamber 130 are also provided with a vent nozzle 123 and a drain nozzle 133.

(Leakage inspection)
In the above-described condenser 100, an example will be described in which inspection is performed for the presence or absence of leakage at the joint between the tube sheets 112 and 113 and the cooling pipe 111. The leakage as described above may occur, for example, when the damaged cooling pipe 111 is replaced, especially when the old cooling pipe 111 is pulled out from the through holes of the tube sheets 112 and 113, the inner surface of the through hole is damaged, or the groove is formed. It is more likely to occur when is scraped off.

  (S101) First, the manhole covers 121 and 131 of the cooling water inflow chamber 120 and the cooling water outflow chamber 130 are removed to open the manhole, and the worker enters the inside of the cooling water inflow chamber 120 and the cooling water outflow chamber 130 to perform work. To be able to.

  (S102) As shown in FIG. 2, the water blocking balls 161, 162 (sealing members) are inserted into the cooling water inflow pipe 122 and the cooling water outflow pipe 132, and the cooling water inflow chamber 120 is expanded by expansion by the injection of air. And the cooling water outflow chamber 130 is brought into a sealable state.

  (S103) The pressure gauge 143 (vacuum gauge) and the regulator 144 (vacuum regulator) are connected to the vent nozzle 123 of the cooling water inflow chamber 120 via the valve 141 and the hose 142.

  (S104) The pressure reducing pump 152 (vacuum pump) is connected to the drain nozzle 133 of the cooling water outflow chamber 130 via the valve 151.

  (S105) A leakage inspection agent such as Moremir W manufactured by TASETO CORPORATION is applied near the joint between the tube plates 112 and 113 and the cooling pipe 111 on the side of the cooling water inflow chamber 120 or the cooling water outflow chamber 130. ..

  (S106) The manhole covers 121 and 131 close the manholes of the cooling water inflow chamber 120 and the cooling water outflow chamber 130.

  (S107) The pressure reducing pump 152 keeps the pressure below −0.05 MPaG for 10 minutes, for example. At the same time, water (reaction liquid of the leak test agent) is sprayed or sprayed in the vicinity of the joint between the tube plates 112 and 113 and the cooling pipe 111 on the inner side of the body 110 of the condenser 100. Accordingly, when there is a leak in the joint portion, the sprayed water permeates into the cooling water inflow chamber 120 or the cooling water outflow chamber 130 by suction due to negative pressure or a capillary phenomenon, and the moremeal W is colored red.

  The water to be sprayed should be purified water of the same quality or better than the fluid used during operation. Also, in order to make sure that all the cooling pipe joints of the condenser can be spread over the water, gaps in the arrangement of cooling pipes should be Straight jet of water pressurized along the line or water droplets generated by a spray nozzle are conveyed by compressed air for application.

  (S108) Then, when the manhole covers 121 and 131 are removed again after the depressurization is released, it is possible to easily visually confirm the presence or absence of leakage in the plurality of cooling pipes 111. It is also easy to record by taking a picture.

  (S109, S110) When color development (leakage) is confirmed, for example, after taking measures such as expansion of the cooling pipe 111, the above (S105) and subsequent steps are repeated.

  (S111, S112) When the color development of the moremeal W is not confirmed, the water stop balls 161, 162 in the cooling water inflow pipe 122 and the cooling water outflow pipe 132 are removed, and the manhole cover 121, 131 cools them. The manholes of the water inflow chamber 120 and the cooling water outflow chamber 130 are closed, and the inspection ends.

  As described above, the cooling water inflow chamber 120 and the cooling water outflow chamber 130 are sealed and decompressed, and the leakage is confirmed by the leakage inspection agent. Can be confirmed collectively and with high reliability. In particular, by making both the cooling water inflow chamber 120 and the cooling water outflow chamber 130 in a depressurized state, it is not necessary to seal one end side of each cooling pipe 111, and a leak test is performed on both end sides of the cooling pipe 111. Can be done simultaneously. Therefore, the inspection time can be greatly shortened, and the workability and reliability can be greatly improved.

  Further, the cooling water inflow chamber 120 and the cooling water outflow chamber 130 as described above can be easily sealed by the water blocking balls 161, 162, and can be easily inspected even during maintenance of the steam turbine.

  Further, by providing the decompression pump 152 on one side of the cooling water inflow chamber 120 and the cooling water outflow chamber 130 and providing the pressure gauge 143 and the regulator 144 on the other side, the cooling water inflow chamber 120, the cooling water outflow chamber 130, and the inside of the cooling pipe 111 are provided. The negative pressure state of can be confirmed and monitored more reliably.

100 Condenser 110 Body 110a Steam inflow part 110b Condensate outflow part 111 Cooling pipe 112/113 Tube plate 120 Cooling water inflow chamber 121 Manhole cover 122 Cooling water inflow pipe 123 Vent nozzle 130 Cooling water outflow chamber 131 Manhole cover 132 Cooling water outflow pipe 133 drain nozzle 141 valve 142 hose 143 pressure gauge 144 regulator 151 valve 152 decompression pump 161, 162 water stop ball

Claims (3)

A leakage inspection method for a condenser, comprising: a pair of tube sheets, a plurality of cooling tubes having both ends joined to the tube sheet, and a body that houses the cooling tubes.
A cooling water inflow chamber communicating with the inside of the cooling pipe, respectively, and a sealing step of bringing the cooling water outflow chamber into a sealed state,
A leakage inspection agent adhering step of adhering a leakage inspection agent to the joint between the cooling pipe and the tube plate on the cooling water inflow chamber side and the cooling water outflow chamber side;
A decompression step of decompressing the cooling water inflow chamber and the cooling water outflow chamber,
A reaction liquid attaching step of attaching the reaction liquid of the leakage inspection agent to the joint between the cooling pipe and the tube sheet on the body side of the cooling pipe,
A leak inspection method for a condenser, comprising: The leakage inspection method for a condenser according to claim 1,
The sealing step is performed by sealing the cooling water inflow pipe communicating with the cooling water inflow chamber and the cooling water outflow pipe communicating with the cooling water outflow chamber by expanding the sealing member. Leak inspection method for water containers. A leakage inspection method for a condenser according to any one of claims 1 and 2,
The leakage check method for a condenser, wherein the decompression step is performed by connecting a decompression pump to one of the cooling water inflow chamber and the cooling water outflow chamber and connecting a pressure gauge to the other.

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