JPS6036521B2 - Safety device for furnace tube boiler - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a safety device for preventing internal combustion of a reverse turn type smoke tube boiler during startup.

In this invention, the term "furnace and smoke tube boiler" is a general term for blind-pupils such as direct-fired absorption type high-temperature regenerators having a similar structure.

Such devices employ a type in which the combustion gas is reverse-turned within the furnace cylinder. Until now, the fuel used was mostly heavy oil, so there were few explosions inside the furnace cylinder, but as higher quality fuels have been used in recent years to prevent pollution, the number of explosions inside the furnace using gas kerosene, etc. has increased. It is in operation.

For this reason, an explosion door has been installed at the rear of the furnace cylinder, but this problem occurs because it is not possible to purge the unburned gas that has accumulated inside the furnace tube before igniting the burner. FIG. 1 shows a conventional furnace and smoke tube boiler. The gas combusted in the burner 4 makes a U-turn in the furnace cylinder 1 and is led to the bonito path 3 from the front of the can through the smoke pipe 2. To prevent combustion accidents within the furnace, an explosion door 5 is provided at the rear of the furnace cylinder to ensure the safety of the furnace cylinder, etc. However, oil droplets due to ignition failure and their vaporized fuel gas have a high specific gravity due to air, and therefore remain at the bottom of the furnace cylinder.

Therefore, if the engine is started (ignitioned) without sufficient purging, the spark from the spark plug will ignite and cause an explosion within the furnace. In particular, in the boiler shown in Figure 1, the flow of combustion gas is reversed in the furnace cylinder, so the dangerous vaporized fuel gas tends to accumulate near the bottom of the furnace on the trailing side (bottom right in the drawing), causing combustion in the furnace. It is the cause of

This invention eliminates these drawbacks, and in order to prevent combustion accidents in the reverse turn type of furnace tube and smoke pipe spoiler,
The object of the present invention is to provide a boiler equipped with an interlock circuit before ignition of a burner and completely releasing unburned gas accumulated in the furnace to the outside of the furnace by pre-purge.

In short, the present invention is characterized by providing a damper at the rear of the furnace cylinder in order to completely purge the gas accumulated in the furnace outside of the furnace before igniting the burner, and interlocking with a pre-purge relay to automatically perform the boiler. do.

One embodiment of the present invention will be explained with reference to the drawings. In Fig. 2, the flow of combustion gas is the same as in a conventional boiler, but one or more unburnt gas purge passages 7 are provided at the rear of the furnace cylinder. A damper 6 is attached to each.

In this case, among the dampers 6 provided in the purge passages 7 in multiple stages (three stages in the illustrated example), the damper 6 in the lowest purge passage 7 is particularly concerned with the gas accumulated at the bottom of the furnace, which has the danger of explosion. It is particularly effective in eliminating

However, opening all the dasopas 6 is suitable for shortening the purge time. In addition, purge passage 7 is connected to each bonito path (chimney).
The connection to the lower part of the chimney is necessary because the smoke exhaust effect (draft) of the chimney allows dangerous gases stagnant in the furnace to be released from the top of the chimney.

From a safety standpoint, it is desirable to dilute the dangerous gas stagnant in the furnace by mixing the purge air from the blower with the stagnant gas, and then release the diluted gas into the atmosphere through the chimney.

Furthermore, a control circuit 9 for the burner 4 is connected to the control box 8 of the furnace tube smoke tube boiler, a blower control circuit 11 is connected to the blower 10' that combines combustion air, and a damper control circuit 12 is connected to the dasopar 6. These three control circuits are connected to the control box 8.
It is interlocked within the

The operating program is as shown in the reference diagram, FIG. 1, and the time is changed according to the boiler capacity.

Next, the purpose of interlocking the damper control circuit, the blower control circuit, and the burner control circuit will be explained.

A reference diagram, FIG. 1, briefly explains the relationship between the fan, the gas barge damper, and the operating time thereof.

In the reference diagram, the blower (fan) and the gas purge damper start operating at the same time, but the gas purge damper and the blower may start at the same time. This is because the purge passage is connected to the chimney and has an exhaust gas effect due to draft. Normally, when a blower is started, it does not immediately emit a large amount of air.
There is no problem even if the blower is started and the purge damper is turned on at the same time. If these two are not interlocked, that is, the blower will not be started or ignited until the purge damper is closed, leaving the cause of combustion in the furnace due to residual explosive gas.

The blower and PANA control are interlocked, and this is the basic interlock for gas purge completion and ignition.

In Figure 1 of the reference diagram, the ignition (spark) is started after blower 6 is completed with sand, the oil is rubbed in step 1 to ensure reliable ignition, and the spark is continued for another 6 seconds to stabilize the flame. There is.

Interlocking the blower control circuit and burner control circuit is necessary for the reasons mentioned above. Overall,
The interlock between the control circuit of the damper 6, the control circuit for starting the blower and securing the purge time, and the burner control circuit related to starting the ignition, operating time, and starting the burner light is to control the operation order, timing, and maintenance of operation. It is extremely important for safe operation of boilers as it ensures time saving. This prevents mistakes in the order of operations and insufficient operation holding time during conventional manual operation, and ensures automatic safe operation of the boiler.

When the furnace tube smoke tube poller is started, the damper 6 is automatically opened during breapage to completely discharge unburned gas to the outside of the furnace.

After the blow purge is completed, an interlock is activated to automatically fully open this dasopa 6 to prevent heat loss due to exhaustion of hot gas from the furnace. Further, after operation, the damper 6 is kept fully open during post-purge. The reverse-turn type smoke tube boiler is economically advantageous because it has a simpler structure than the wet-back type, and with the situation where gas-fired and kerosene-fired boilers are increasing, there is a need for effective operation of these boilers. It becomes a safety device.

By implementing the present invention, combustion within the furnace is prevented, the user's confidence in safety is increased, and the inexpensive river stern type can be used more safely, among other effects.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a conventional fire-tube boiler, and FIG. 2 is a drawing showing the arrangement of diamond pupils and a longitudinal cross-section of the smoke-tube boiler according to the present invention. 1... Furnace cylinder, 2... Smoke pipe, 3...
Flue, 4...burner, 5...wisteria door, 6...
・Damper, 7...Purge passage, 8...Control box, 9...Burner control circuit, 10...Blower,
11... Blower control circuit, 12... Damper control circuit. Figure 1 Figure 2

Claims (1)

[Claims] 1. One or more purge passages including a passage connecting to the opening in the lower part of the furnace tube at the rear of the furnace tube of the furnace tube smoke tube boiler and a control damper connecting the furnace tube rear wall and the flue, and a control box of the furnace tube smoke tube boiler. A burner control circuit, a blower control circuit, and a damper control circuit for the pre-purge passageway are connected to this control box, and the damper control circuit for the purge passageway is opened, the blower is started, the time for purging by the blower is secured, and the duration of the ignition for burner ignition is maintained. A safety device for a furnace smoke tube boiler, characterized in that it is a device for preventing an explosion inside the furnace, and is equipped with an interlock circuit for controlling the burner, including ensuring safety and starting fuel spray.