JP2892630B2 - Cleaning method inside the narrow tube of seawater heat exchanger - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cleaning a thin tube of a seawater heat exchanger used for a heat exchanger of a thermal / nuclear power plant.

[0002]

2. Description of the Related Art In a condenser of a nuclear power plant, tens of thousands of thin tubes are connected between a water chamber and a water chamber, and heat exchange is performed by water reaching a water chamber from a circulating water pipe. I have. However, sludge and the like adhere to the narrow tube due to long-term use. In particular, when seawater is used as circulating water, many shells and other deposits adhere.

[0003] Therefore, removal of deposits in the thin tube is regularly performed. A cleaning brush is inserted into the thin tube, high-pressure water of 7 kg / cm ² is introduced by a cleaning gun, and the brush is brushed to move the cleaning brush in the thin tube. Then, the thin tube is removed for removing residual water and inspecting the thin tube for flaws. Air purge is performed to blow off residual water accumulated in the inside with high-pressure air of 7 kg / cm ² .

[0004]

The number of thin tubes is large, and the operation of applying a cleaning gun to each of the thin tubes is performed twice during the pressure feeding of the cleaning brush and during the air purging. I have. Also, the amount of water used as high-pressure water is large. Further, since the residual water stored in the thin tube is stored under the thin tube, the high-pressure air mainly passes over the residual water even by the high-pressure air, so that it is difficult to remove the residual water in the thin tube.

[0005] Furthermore, the inside of the condenser is high in humidity, and a long-time operation while being wet with the washing water causes a great fatigue for the operator.

[0006]

SUMMARY OF THE INVENTION In view of the above circumstances, the present invention provides a cleaning brush at the entrance of a thin tube in order to shorten the working time, reduce the amount of water used, and remove residual water in the thin tube. Is inserted, high-pressure water flows into the narrow tube inlet, and the cleaning brush is pumped.At the same time, the high-pressure air flows into the small tube while the high-pressure water flows into the small tube during the movement of the cleaning brush in the narrow tube, and the cleaning brush is pumped. After the high pressure water mass pumps the cleaning brush and passes the high pressure water through the narrow tube, it is converted into mist high pressure air, then high pressure air with almost no moisture. A method of cleaning the inside of the thin tube of the seawater heat exchanger without water was used.

Specifically, the present invention provides a timing for switching from the inflow of high-pressure water to a capillary to the inflow of high-pressure air,
The method for cleaning the inside of the capillary of the seawater heat exchanger was set when the cleaning brush passed through the middle position of the capillary. Further, the present invention provides a method of cleaning a seawater heat exchanger in which residual water is purged simultaneously with cleaning of each capillary so that the capillary undergoes eddy current inspection after cleaning.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described in more detail hereinafter with reference to specific embodiments illustrated in the accompanying drawings, in which: FIG. FIG. 1 shows an outline of a condenser, in which the water chamber 1 is connected to the water chamber 1 by a large number of tens of thousands of horizontal thin tubes 2, and is heated by water reaching the water chamber 1 from the circulating water pipe 3. Exchange is being performed.

A cleaning brush 4 is inserted into the inlet of the thin tube 2, a cleaning gun 5 is applied to the end face of the thin tube 2 on the inlet side, and high-pressure water is applied to the thin tube 2.
And the cleaning brush 4 is pressure-fed, and while the cleaning brush 4 is moving through the thin tube 2, the high-pressure water is blocked from flowing into the thin tube 2, and at the same time, high-pressure air is sent from the cleaning gun 5 to the small tube 2.
And the cleaning brush 4 is fed under pressure to wash the inside of the thin tube 2.

FIG. 2 shows the cleaning gun 5. A nozzle 12 is attached to the tip of the cleaning gun body 11, a handle 13 is erected vertically on the base end side of the cleaning gun body 11, a hose 15 is connected via a coupler 14, and a high-pressure air is connected via a coupler 16. A solenoid valve 17 for high pressure water and a solenoid valve 18 for high pressure water are provided between the solenoid valve 17 for high pressure air and the coupler 16 and the solenoid valve 18 for high pressure water and the coupler 16.
And check valves 19 and 20 are interposed therebetween.

The changeover switch and the timer are housed in a waterproof box. High pressure water solenoid valve operation switch 2
1 and solenoid valve operation switch 22 for high pressure air and manual
An automatic changeover switch 23 and a power supply socket 24 are provided. Reference numeral 25 denotes a timer, and 26 denotes a box. The thin tube here has, for example, an inner diameter of about 25 mm, a length of about 17 m, and the material of the thin tube is a titanium tube or a yellow steel tube.

Further, the cleaning brush is one in which the brush is sandwiched between two wires and twisted, and both ends thereof are fixed to a rubber guide. When the cleaning brush is inserted into the thin tube, a slight gap is formed between the outer periphery of the guide and the inner surface of the thin tube. Is set so that there is a gap. While the cleaning brush is moving through the capillary, the high-pressure water is blocked from flowing into the capillary,
After that, when high-pressure air with a pressure higher than the high-pressure water pressure is introduced into the thin tube, the high-pressure water moves as a lump between the cleaning brush and the high-pressure air. did.

The test was performed as shown in FIG. An acrylic test thin tube 31 made of a light-transmissive material is used as the thin tube. The thin tube 31 is horizontally supported on a table 32, a cleaning brush 33 is used, and high-pressure water and high-pressure air are introduced by a cleaning gun 34. It was done. Note that the cleaning brush 33 has a structure in which both ends are fixed to rubber guides 37 by pinching and twisting the brush 35 between two wires 36.

FIG. 4 shows the situation at the intermediate position of the thin tube 31, and FIG. 5 shows the situation at the outlet end of the thin tube 31. Cleaning brush 33
Is inserted into the test tube 31, and the cleaning gun 34 is connected to the tube 31.
When high-pressure water is caused to flow into the thin tube 31, high-pressure water first flows in an intermediate position of the thin tube 31 as shown in FIG. This is presumably because high-pressure water passes between the thin tube 31 and the guide 37 of the cleaning brush 31 so that the pressure at that location drops and the high-pressure water arrives before the cleaning brush 33.

Subsequently, as shown in FIG. 4B, the cleaning brush 33 reaches the intermediate position, and when the cleaning gun 34 is subsequently switched to high-pressure air, a state as shown in FIG. 4C is obtained. It is considered that the high-pressure air is conically penetrating into the high-pressure water due to a frictional force between the high-pressure air and the inner surface of the thin tube 31. After the high-pressure water passes through the intermediate position, mist-like high-pressure air passes. This is probably because the high-pressure water that had passed before adhered to the inner surface of the thin tube 31 and was mixed into the high-pressure air. When the high-pressure air subsequently passes through the intermediate position, as shown in FIG. 4E, the inner surface of the thin tube 31 has almost no moisture, and after the inflow of the high-pressure air is shut off, there is no remaining water in the thin tube 31.

At the outlet end of the thin tube 31 shown in FIG.
High-pressure water flows out as shown in FIG. 5a. Subsequently, the cleaning brush 33 reaches the outlet side pipe end and falls, and after the high-pressure water flows out, as shown in FIG.
Subsequently, high-pressure air with almost no moisture shown in FIG.
After the high-pressure air is stopped, there is no remaining water as shown in FIG. 5D.

When the cleaning brush in the thin tube is pressure-fed by high-pressure water, high-pressure water is stopped on the way, and high-pressure air is allowed to flow.
It can be seen that the high pressure water mass is pumping the cleaning brush.

[0018]

As described above, according to the present invention, the cleaning brush is inserted into the inlet of the thin tube, high-pressure water flows into the inlet of the thin tube, and the cleaning brush is pumped. At the same time as blocking the inflow into the small tube, high-pressure air flows into the small tube and the cleaning brush is pumped, and a mass of high-pressure water pumps the cleaning brush, and after passing the high-pressure water through the small tube, the atomized high pressure Air and then high pressure air with almost no water content.After stopping the high pressure air, it is a method of cleaning the narrow tube of the seawater heat exchanger with no residual water inside the narrow tube. The cleaning gun has to be applied to the thin tube twice for the inflow only once and the working time can be reduced. In addition, since the inflow of high-pressure water is stopped halfway and high-pressure air is used thereafter, the amount of water used and the amount of washing and drainage can be reduced. Further, the present invention provides a method in which a high-pressure water mass feeds a cleaning brush, passes high-pressure water through a narrow tube, forms high-pressure air in the form of mist, and subsequently changes to high-pressure air with almost no moisture. The inside of the thin tube can be made free of residual water. Therefore, since residual water does not accumulate in the thin tube, it is suitable for subsequent overcurrent inspection of the thin tube.

Further, the present invention specifically provides a timing for switching from the inflow of high-pressure water to the capillary to the inflow of high-pressure air.
The method for cleaning the inside of the capillary of the seawater heat exchanger was set when the cleaning brush passed through the middle position of the capillary. Further, the present invention is a method for cleaning the inside of a thin tube of a seawater heat exchanger in which the thin tube undergoes eddy current inspection, so that residual water does not accumulate in the thin tube,
It is suitable for the subsequent eddy current inspection of thin tubes.

Furthermore, if the high-pressure air is automatically made to flow from the high-pressure water, the washing operation can be performed in two to one steps as compared with the conventional manual operation. Worker fatigue in the house is reduced.

[Brief description of the drawings]

FIG. 1 is a view showing a condenser according to the present invention.

FIG. 2 is an explanatory view of a cleaning gun according to the present invention.

FIG. 3 is a schematic diagram of a test apparatus of the present invention.

FIG. 4 is a diagram for explaining a situation at an intermediate position of a thin tube in a test.

FIG. 5 is a view for explaining the situation of the outlet end of the thin tube in the test.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Water chamber 2 ... Thin tube 3 ... Circulating water pipe 4 ... Cleaning brush 5 ... Cleaning gun 11 ... Cleaning gun main body 12 ... Nozzle 13 ... Handle 14 ... Coupler 15 ... Hose 16 ... Coupler 17 ... Solenoid valve for high pressure air 18 ... High pressure water Solenoid valves 19/20 ... Check valve 21 ... Solenoid valve operation switch for high pressure water 22 ... Solenoid valve operation switch for high pressure air 23 ... Changeover switch 24 ... Power plug 31 ... Thin tube 32 ... Table 33 ... Cleaning brush 34 ... Cleaning gun 35 ... brush 36 ... wire 37 ... guide

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F28G 1/12

Claims (3)

(57) [Claims] 1. A cleaning brush is inserted into an inlet of a thin tube, high-pressure water flows into the inlet of the thin tube, and the cleaning brush is fed under pressure. High-pressure air flows into the thin tube and the cleaning brush is fed under pressure.Lumps of high-pressure water feed the cleaning brush, and after passing high-pressure water through the narrow tube, it is turned into mist-like high-pressure air,
Subsequently, high-pressure air with almost no moisture is used, and after the high-pressure air is stopped, the inside of the thin tube of the seawater heat exchanger is cleaned without remaining water. 2. The seawater heat exchanger according to claim 1, wherein the timing of switching from the inflow of high-pressure water to the high-pressure air to the high-pressure air is set when the cleaning brush passes an intermediate position of the thin tube. Cleaning method. 3. The method according to claim 1, wherein the thin tube undergoes an eddy current inspection.