JP2889779B2 - Cleaning method of steam generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a boiler-type steam generator, which is a scale that is concentrated as a result of evaporation in an evaporating tank and that precipitates from residual water having high hardness. Steam generated in a steam generator equipped with a filter for preventing scale outflow near the drainage port of the evaporation tank so that scale pieces that may have an adverse effect such as clogging of pipes and drain valves are not discharged outside the evaporation tank. It relates to the method used to clean the vessel.

[0002]

2. Description of the Related Art Conventionally, generally, an evaporating tank of a steam generator is washed by filling the evaporating tank with water and then draining the water. However, in a structure in which the scale pieces are temporarily stored in the evaporating tank, a method of simply cleaning the inside of the evaporating tank does not provide an effect enough to restore the water permeability of the scale reservoir at the lower part of the evaporating tank.

On the other hand, in order to improve this point, only the lower part of the evaporating tank is repeatedly washed, but in this case, the water permeability is restored by washing the vicinity of the scale reservoir at the lower part of the evaporating tank. The inner surface of the nearby evaporating tank was also cleaned, but the entire surface of the evaporating tank was not cleaned.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a cleaning method for restoring the water permeability of a scale accumulating portion at a lower portion of an evaporating tank. It is an object of the present invention to provide a method of cleaning a steam generator, which can perform cleaning of the entire immersion surface.

[0005]

In order to achieve the above object, a method for cleaning a steam generator according to the present invention is of a boiling type,
In a steam generator provided with a filter 3 near the drain port 2 at the lower portion of the evaporating tank 1 for preventing the scale from being generated inside the evaporating tank 1, after steam is generated, residual water in the evaporating tank 1 is discharged. After discharging the water, water is supplied to the vicinity of the outlet 2 of the evaporating tank 1 and the scale stagnant portion in the vicinity of the outlet 2 of the evaporating tank 1 is washed at least once by using the water supply pressure. Fill up to the flooded surface inside the
Then, the concentrated water in the evaporating tank 1 is washed out by draining.

[0006]

According to the above construction, the drain port 2 at the lower part of the evaporating tank 1 is provided.
Since water is supplied to the portion where the scale in the vicinity of the stagnation stays and washed with the water supply pressure, the stagnation of the scale can be reliably removed. Further, after removing the stagnation of the scale, the inside of the evaporation tank 1 is filled with water, and the entire inside of the evaporation tank 1 can be washed by draining and washing away the concentrated water in the evaporation tank 1.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIGS. 1 and 2, reference numeral 1 denotes an evaporating tank, and a lid 5 is attached to the upper surface. A heating heater 6 for heating and evaporating water inside the evaporation tank 1 is provided in the evaporation tank 1.
An electrode rod 7 serving as a water level sensor for detecting a water level in the inside is hung downward from the lid 5, and the lid 5 is provided with a scale inspection port 8. In the evaporating tank 1, scale precipitated from residual water (hot water) having a high hardness due to evaporation adheres to the inner wall surface of the tank and the surface of the heater 6, and peels off and sinks as scale pieces on the bottom surface. A drain port 2 is provided at a lower portion of the evaporating tank 1, and a drain pipe 9 is connected to the drain port 2,
The drain pipe 9 is provided with a motor-operated valve 10 so that a water channel can be opened and closed. At this time, if the scale directly flows into the drain pipe 9, the drain pipe 9 may be clogged or the electric valve 10 may be clogged.
Therefore, a filter 3 is provided above the drain port 2 of the evaporating tank 1. The filter 3 is, for example, a punching metal having an opening smaller than the diameter of the pipe,
They are arranged in an inverted V-shape.

A water supply pipe 11 is connected to a lower portion of the evaporating tank 1 and is directed to a filter 3 so that water is supplied to the filter 3 at a water supply port 11a provided at the end of the water supply pipe 11 so that water can be supplied to the filter 3 at a water supply pressure. The water supply pipe 11 is provided with an electric valve 12 for opening and closing a water channel, a check valve 13, and a drain pipe 14. The water level in the evaporation tank 1 is detected by an electrode rod serving as the water level sensor, and the water level is controlled by electric valves 10 and 12.

After steam is supplied to the evaporating tank 1 until it is full,
It is heated to a boiling state by the heater 6 and discharged from the steam pipe 15 at a vapor pressure. Since the concentration of calcium and the like in the water increases due to evaporation and scale easily precipitates, the steam generation time (heater heating time) is limited to a certain time so that the concentration ratio with respect to the initial stage of water supply does not become too high. If the fixed time is exceeded, all the hot water in the evaporating tank 1 is discharged. If the fixed time is not exceeded, the hot water is held in the evaporating tank 1 with a higher hardness than in the initial stage of water supply. In this case, after a certain period of time has elapsed since the operation switch was turned off, if there is little possibility of continued use, residual water (hot water) is discharged, and the inside of the evaporating tank 1 is cleaned as follows.

First, water is applied to the filter 3 from the water supply port 11a using the water supply pressure supplied from the water supply pipe 11, and after the water is washed while the discharge path is not blocked and the water permeability is improved. Drain. After repeating this at least one cycle in a cycle of several tens of seconds, water is supplied to the evaporating tank 1 so as to be full, and the entire inundation surface in the evaporating tank 1 is washed and discharged. The scale inside the evaporating tank 1 is the scale inspection port 8
More specifically, a dedicated cleaning agent is added at regular intervals to carry out dissolution cleaning.

[0011]

According to the present invention, as described above, after steam is generated,
The residual water in the evaporation tank is discharged, and after discharging the residual water, water is supplied to the vicinity of the discharge port of the evaporation tank, and the scale stagnant portion near the discharge port of the evaporation tank is washed at least once using the water supply pressure. The filter is cleaned so as not to block the filter etc. due to the accumulation of scale at the lower part of the evaporating tank, the operation reliability is improved, the maintenance cycle can be lengthened, and the usability can be further improved. After washing the scale accumulating part, the inside of the evaporating tank is filled with water and then drained to wash away the concentrated water in the evaporating tank. The entire surface is cleaned so that water does not adhere, and there is no concern that residual water evaporates and dries and adheres to the inner wall surface of the evaporating tank as a scale, thus improving the scale resistance.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view of a steam generator embodying the present invention.

FIG. 2 is a side view of the same.

[Explanation of symbols]

 1 Evaporation tank 2 Drain outlet 3 Filter

Claims (1)

(57) [Claims] 1. A steam generator which is of a boiling type and is provided with a filter near a drain port at a lower portion of an evaporating tank to prevent outflow of scale generated inside the evaporating tank. The water is discharged, and after the residual water is discharged, water is supplied to the vicinity of the discharge port of the evaporating tank, and at least one or more times of washing of the scale stagnant portion near the discharge port of the evaporating tank using the water supply pressure are performed, and then the evaporating operation A method for cleaning a steam generator, comprising filling a tank with water to a flooded surface, draining the water, and washing away concentrated water in the evaporation tank.