JPS58155327A - Discovering method for leaking pipe in exhaust gas economizer - Google Patents

Abstract

PURPOSE:To discover a leaking pipe in a short time through safe operation by closing the inlet and outlet of exhaust gas and making air flow into the casing and then closing the air valve when specified pressure is reached in the casing and reading the pressure drop in the casing. CONSTITUTION:Blind flanges 20 are inserted through the manholes 10 and 11 respectively to install them to inside flanges 3b and 7b of respective exhaust gas outlet 3 and exhaust gas inlet 7 for completely shutting the exhaust ducts. Air is introduced into the casing 2 by opening slightly an air valve 21, and the air pressure in the casing is increased to a specified pressure by looking at a pressure gauge 23. After the prssure is increased in this way, the air valve 21 is totally closed and the pressure gauge is read. When the pressure falls below 300mm.Hg,, it indicates that there is a leaking pipe. For the leakage, discovery operation for which bent pipe 15a is leaking is started at once. In this case, the air pressure is held at 300mm.Hg by slightly opening the air valve 21 again, and then it is possible to find the row of pipes in which a leaking pipe exists by leaking air that comes from it, if the manual hole plug that is provided for the bent pipe 15a at the pipe header 18 is opened one by one successively.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for discovering leakage pipes in a casing in an exhaust gas economizer that heats boiler feed water using exhaust gas from an internal combustion engine.

This type of exhaust gas economizer is generally lined with a heat insulating material, has a bent pipe inside the casing, circulates the boiler feed water guided into this pipe, and exhausts this circulating water from the gas inlet of the casing to the gas outlet. It is heated with gas. In such exhaust gas economizers, after long-term use, the piping inside the casing may become damaged and water may leak. Conventionally, the following methods have been adopted to discover this leaking pipe.

That is, first, the main engine is stopped or the supply of exhaust gas to the economizer is completely cut off, and then the casing door is opened to introduce clean air into the casing to completely scavenge the exhaust gas. Then, either go inside the casing and look for the pipe that is spouting water, or drain the water inside the pipe, cool the pipe, and then look for the leak pipe.If you still can't find it, use a circulation pump, etc. After filling the casing with water and applying water pressure, search for leakage pipes. If you still can't find it, drain the water from the casing and piping completely, close one end of the pipe with a plug, feed compressed air into the pipe from the other end, and check for the sound of air blowing inside the casing. Find the leaking pipe.

This conventional method for detecting leak pipes is dangerous because it requires a lot of work inside the casing. The drawback is that it requires a lot of time and skill.

The present invention was made in view of the above points, and the inlet and outlet of exhaust gas are closed with a lid body to isolate them from the exhaust gas duct, air is sent into the casing, and when a predetermined pressure is reached, the air is released. The exhaust gas system is configured to detect leakage pipes by closing the valve and reading the pressure drop inside the casing with a pressure needle, making it possible to quickly and easily find leakage pipes through safe work. This invention provides a method for finding leakage pipes in an economizer. Embodiments of the present invention will be described in detail below with reference to the drawings.

Fig. 1 is a vertical cross-sectional view of a waste gas economizer for explaining the leakage pipe detection method according to the present invention, and Fig. 2 is a longitudinal cross-sectional view of the exhaust gas economizer.
The figure is a side view from a human perspective, and FIG. 3 is a plan view of the front and back surfaces of the lid body. In the figure, the casing 2 of the exhaust gas economizer 1 is formed into a rectangular tube shape with a bottom end, and has an upper outlet 3 on the upper end II plate 4. is lined with insulation material. Further, an exhaust gas manifold lower having flanges 7a and 7b at both ends is fitted and fixed into a circular hole formed in the lower side 11 of the casing, and the exhaust gas manifold lower and the exhaust gas outlet 3 are located in the vicinity thereof. The nine manholes 1° and 11 are closed with lids 8 and 9 that can be opened and closed. Further, the bottom surface of the casing 2 is inclined in one direction, and a drain port 12 is attached to the lower side surface thereof.

A beam square pipe withdrawal hole 13 opened above the gas port 1 is closed with a door 14 that can be opened and closed, and an economizer pipe 15 inserted through the pipe withdrawal hole 13 is inside the casing 2. is provided. The economizer tube 15 is held by a pair of holding frames 16 and is formed of a plurality of bent tubes 15a arranged in parallel in the horizontal direction.
They are kept warm and arranged in two rows, upper and lower, and connected to round headers 11 and 11, respectively. Each of the headers Ill and II is formed into a tubular shape and has one end blindly closed, and the other end of the lower header II is connected to the drain port side of a circulating pump for boiler water supply (not shown). The other end of the upper header 1 is connected to the water supply section of the boiler.

Exhaust gas ducts (not shown) for supplying and discharging exhaust gas from a diesel engine (not shown) are connected to the external flanges 31.71 of the exhaust gas outlet q3 and the exhaust gas man lower, respectively, and internal flanges 3b, TbK is provided with a removably blind flange 20 as a lid shown in FIG.

The blind flange 20 is formed into a disk shape by joining a pair of semicircular members with a hinge 20b via a sheet packing 20a, and folds it in half to attach the manhole 10. 11 into the casing 2, spread it out into a disk shape, fix it with a hook 20C and a pin 20d, and then join it to the flanges 3b and 7b.

Furthermore, the lower end wIK of the casing 2 is equipped with an air valve 11 and is connected to an air supply device (not shown), into which a nine-way trachea 22 is inserted and fixed. It is configured so that it can be blown into the interior of the tank.

Reference numeral 23 denotes a U-shaped KvIII 11 air pressure needle that displays the air pressure inside the casing 2, and is attached to the casing 2 via a socket 24.

In the exhaust gas economizer 1 configured as described above, the water supplied to the boiler is pressurized by the circulation pump, enters each l1llI pipe ISm of the economizer pipe 1s from the lower header 1-, and is circulated within the casing 2. After that, it is supplied to the boiler via the header 1@ in the upper stage. On the other hand, the exhaust gas of the diesel engine is discharged from the exhaust gas population 1 into the casing 1 through the exhaust gas duct and into the atmosphere from the exhaust gas outlet 3 through the exhaust gas duct. And each person has a p-tube Ba.
The boiler feed water circulating inside the casing 2 is heated by the exhaust gas after passing through the casing 2, becomes high temperature, and is supplied to the boiler.

Therefore, a method for detecting a leak pipe in such an exhaust gas economizer 1 will be explained. First, blind flange 2
0 in half) and insert them from the manholes 10 and 11, open them into a circular shape and attach the hook 20c and pin 20.
d and then attached to the internal flanges 3b and 7b of the exhaust gas outlet 3 and exhaust gas port 1. In this case, the interior of the casing is completely isolated from the exhaust gas duct. Therefore, the air valve 21 is slightly opened to supply air to the casing 2.
Then, while watching the pressure gauge 23, increase the air pressure to a predetermined pressure. In this embodiment, the predetermined pressure is set at 300 mA, which is a necessary and sufficient value from the viewpoint of detecting leakage pipes and improving the strength of the casing 2. After increasing the pressure in this way, close the air valve 21 fully and read the scale of the pressure needle). 15m
We will begin work to discover if the information has been leaked. In this case, open the air valve 21 slightly again to maintain the air pressure at 300 mA, and then insert the 90-hole plugs into the header 11 in each row one by one. As they close, the leaking pipe array can be discovered by the air flowing out. As a result, if no air flows out of any row, this means that a crack has occurred in the casing 2, and the crack location can be found by carefully examining the outer wall inside the casing. In addition, when increasing the pressure inside the casing 2, it is desirable to equip the drain port 12 with a safety water sealing device. This safety water seal device fills water in a container, connects it with the drain port using a short pipe, and when the pressure inside the casing 2 exceeds 300 mAg, the water in the container is blown away to create pressure. It may be of simple structure with K so that it can escape.

In addition, in this embodiment, a blind flange 20 is provided as a body that blocks the exhaust gas outlet 3 and the exhaust gas lower part,
Although an example of use within the casing 2 has been shown, for example, the exhaust gas outlet 3. If there is sufficient space, such as by providing the glasses 7 lunge at the joint between the exhaust gas population 1 and the exhaust gas duct for opening and closing, it is easier to operate if the lid body is provided outside the casing 2.

As is clear from the above explanation, according to the present invention, in the method for detecting a leak pipe in an exhaust gas economizer, the exhaust gas inlet and outlet are closed with a lid body to isolate them from the exhaust gas duct, and air is allowed to flow into the casing. It is very easy to configure the system so that when the air valve is injected and the predetermined pressure is exceeded, the air valve is closed and the pressure drop inside the casing is detected with a pressure needle to find the leakage pipe, and no experience is required. Since leakage pipes can be discovered in a short time, work efficiency is significantly improved, and work inside the casing is no longer required, so work safety is improved. Furthermore, if a hand stopper is provided at the header of the economizer pipe and the outflow of air is checked by opening and closing the stopper, leakage pipe rows can be easily discovered. Furthermore, since cracks in the casing can be discovered at the same time as leakage pipes are discovered, there is no need to use a separate method for this purpose, which is efficient.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view of an exhaust gas economizer for explaining the method of detecting leakage pipes in an exhaust gas economizer according to the present invention, Fig. 2 is a view taken from surface A of Fig. 1, and Fig. 3 is a view of the lid. FIG. 3 is a plan view of the front and back surfaces of the body. 1...Exhaust economizer, 2...Casing
311@...Exhaust gas outlet, 7...Exhaust gas population, 15
...Economizer pipe, 20...e @ flange, 21 fist e...air valve, 23-〇...pressure needle. Patent applicant Mitsui Engineering & Shipbuilding Co., Ltd. agent Masaki Yamakawa (and one other person)

Claims (1)

[Claims] The exhaust gas inlet and exhaust gas outlet of the casing are closed with a lid, and then the air valve is slightly opened to send air into the casing. When a predetermined pressure is reached, the air valve is fully closed and the air inside the casing is closed. Check the pressure drop with a pressure needle! A method for detecting leakage pipes in exhaust gas economizers, in which the detection of leakage pipes is a percentage value.