JPH0443684Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] This invention relates to a boiler capable of rapidly raising the pressure of a furnace-tube boiler without a circulation pump, which can shorten the boiler pressure-boosting time.

[Background of the idea]

In a conventionally known natural circulation boiler without a circulation pump, particularly in the furnace tube and smoke tube boiler shown in FIG. Because the circulation path of water is not constant, stagnation occurs in the canned water section 5, and when increasing the pressure of the boiler, the rate of increase in the metal temperature 5a of the canned water section 5 and the metal temperature 6a of the evaporation section 6 is as shown in Fig. 5. As shown, a large difference occurs, and the temperature difference between the two metal temperatures 5a and 6a causes thermal stress to occur in the can body 4, which constitutes the pressure section of the boiler.If the pressure increase rate is increased, thermal stress occurs in the can body 4. Since the thermal stress increases and there is a risk of damage to the can body 4, there is a problem in that the pressure increase rate must be reduced to increase the time required for pressure increase. In Fig. 4, 1 is a burner, 2 is a furnace tube, and 3 is a smoke pipe.

In order to solve the above problem, as shown in Fig. 6, the low-temperature canned water accumulated in the canned water section 5 is forcedly circulated to the steam section 6 by the circulation pump 7, so that the temperature of the entire canned water is uniform. A method is adopted in which the temperature difference between the metal temperature 5a of the canned water section 5 and the metal temperature 6a of the steam section 6 is reduced by
Because of the high cost, it is necessary to use composite materials for the main parts of the circulation pump 7, which has the disadvantage of making the equipment expensive.

[Purpose of invention]

An object of the present invention is to provide a boiler capable of rapidly increasing the pressure of the boiler by causing the can water in the can body to flow during the boiler pressure increase, and by equalizing the temperature of the can water and suppressing the occurrence of thermal stress in the can body.

[Summary of the idea]

The boiler capable of rapid boosting of the present invention is a boiler capable of rapid boosting which has an extraction pipe that communicates the bottom of the barrel of the furnace-and-fire-tube boiler with the suction side of the feedwater pump, and is operated by a pressure switch provided on the barrel. An intermittent on-off valve is provided in the extraction pipe.

According to the above configuration, when the pressure in the can body rises to a predetermined value during boosting of the boiler, the pressure switch detects this and controls the intermittent solenoid valve to open, thereby reducing the temperature accumulated in the inner bottom of the can body. The canned water with a low temperature can be extracted to the outside of the can, the flow of the canned water can be increased, the temperature of the entire canned water can be made uniform, the generation of thermal stress can be suppressed, and the pressure increase rate can be increased.

[Example of idea]

Embodiments of the present invention will be described below with reference to FIGS. 1 to 3. Note that the same reference numerals as in the known example indicate the same thing.

FIG. 1 shows an embodiment of the present invention. One end of an extraction pipe 11 is connected and opened at the bottom of the can body 4, and the other end is communicated with a water supply tank 12. The extraction pipe 11 is provided with a canned water flow rate control valve 9 and an intermittent solenoid valve 10, and the intermittent solenoid valve 10 is intermittently opened and closed by the output of the pressure switch 13 provided in the evaporation section 6. The temperature of the canned water is averaged by extracting the water and guiding it to the water supply tank 12 to promote the flow of the canned water. 8 is a water supply pump.

Next, the operation of this embodiment will be explained.

When the boiler pressure is increased, steam is not allowed to flow out, so the pressure rises, and when the pressure in the can body 4 rises to a predetermined value that is higher than the value that allows extraction of low-temperature can water, the pressure switch 13 is activated.
detects this and intermittently opens and closes the intermittent solenoid valve 10. When the intermittent solenoid valve 10 opens, the low-temperature canned water at the bottom of the can body 4 flows into the water tank 12 via the extraction pipe 11 due to the internal pressure of the can body 4 without using a circulation pump. The intermittent opening and closing of the intermittent solenoid valve 10 further promotes the flow and mixing of canned water. The low-temperature canned water extracted by the water supply pump 8 is transferred to the water supply tank 1.
2 to the upper part of the can body 4, and the high-temperature can water at the upper part of the can body 4 is moved by gravity to the bottom of the can body 4 to equalize the temperature of the entire can water and reduce thermal stress in the can body 4. enables rapid pressure increase.

[Effect of idea]

As mentioned above, according to the present invention, when the pressure in the can body rises to a predetermined value when the boiler pressure is increased, the pressure is detected by the pressure switch and the intermittent on-off valve is operated to extract the can water at the bottom of the can body. By this, the can water can be made to flow and the can water temperature can be averaged without using an expensive circulation pump, and the metal temperature 5 of the can water part 5 can be adjusted.
Since the temperature difference between a and the metal temperature 6a of the evaporation section 6 can be made small as shown in FIG. 3, the generated thermal stress is extremely small, and the boiler pressurization rate can be increased.
The time required to boost the boiler pressure, which conventionally took 1 to 2 hours, can be reduced to less than 30 minutes.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a boiler according to an embodiment of the present invention, Fig. 3 is a diagram showing the relationship between metal temperature and time of the boiler according to the present invention, and Fig. 4 is a cross-sectional view of a conventional fire tube boiler. , FIG. 5 is a diagram showing the relationship between metal temperature and time of a conventionally known furnace-tube boiler, and FIG. 6 is a sectional view of a furnace-tube fire-tube boiler having a circulation pump. 1...burner, 2...furnace tube, 3...smoke pipe, 4...
... Can body, 5 ... Can water section, 6 ... Evaporation section, 8 ... Water supply pump, 9 ... Can water flow rate adjustment valve, 10 ... Intermittent solenoid valve, 11 ... Extraction pipe, 12 ... Water supply tank ,
13...Pressure switch.

Claims (1)

[Scope of utility model registration request] In a boiler that is capable of rapid pressurization and has an extraction pipe that communicates the bottom of the can body of the furnace and smoke tube boiler with the suction side of the feed water pump, the extraction pipe is provided with an intermittent on-off valve that is operated by a pressure switch provided in the can body. A boiler capable of rapid boosting.