JPH046000Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to an intake combustion type exhaust gas vent provided in the front chamber of an atmospheric furnace that uses flammable atmospheric gas.

Prior Art and its Problems As a heat treatment furnace (atmosphere furnace) that uses flammable atmospheric gas, the one shown in FIG. 4 is known. In the figure, 1 is a heating chamber, 2 is a front chamber called bestible, and the drawing shows the front chamber (oil tank chamber) integrated with an oil tank. 3 is an intermediate door between the heating chamber 1 and the front chamber 2, and 4 is an exhaust gas vent provided in the front chamber 2. The inside of the front chamber 2 where the oil tank is located is at room temperature, and the inside of the heating chamber 1 is at high temperature. Therefore, when the intermediate door 3 is opened, the atmospheric temperature in the front chamber 2 rises, the internal pressure increases due to volumetric expansion, and atmospheric gas is discharged to the outside from the vent 4 in proportion to the increased pressure. Then, when the intermediate door 3 is closed, the atmospheric temperature in the front chamber 2 drops to the original temperature, and the internal pressure decreases, so that air is sucked through the vent 4.

However, in such a conventional furnace, the intermediate door 3
The drop (fluctuation) in internal pressure is large when the valve is closed, and pressure recovery after reaching negative pressure is slow. Therefore, the amount of atmosphere gas used to speed up pressure recovery increases, and furthermore, pressure fluctuations are large, making it difficult to control the atmosphere. Furthermore, if atmospheric air is sucked in when the inside of the front chamber 2 has a negative pressure, there is a risk that the flammable atmospheric gas will explode, and in order to prevent this, purging with an inert gas is required.

The purpose of this invention is to provide an intake combustion type exhaust gas vent that solves all of the above problems.

Means for solving the problem The intake-combustion type exhaust gas vent according to this invention is equipped with a vent valve to keep the pressure in the furnace constant and a burner placed near the vent valve, so that the pressure in the furnace becomes negative pressure. When the burner becomes hot, the burner is ignited and a vent valve is opened to draw in atmospheric air, which is used for combustion in the burner and then supplied into the furnace.

Function When the pressure inside the furnace becomes negative, the vent valve is opened to suck in the atmosphere, so the pressure drop is small, the pressure recovers quickly, and the consumption of atmospheric gas is small. Furthermore, since the sucked atmosphere is used for combustion in the burner and then supplied into the furnace, there is no risk of explosion of the atmospheric gas, and purging with an inert gas is not required.

Embodiment FIG. 1 shows an example of an intake combustion type exhaust gas vent 11 provided in a front chamber 10 of an atmospheric furnace, and FIG. 2 shows an enlarged view of the upper part of this vent 11.

The vent main body 12 has a cylindrical shape, and a vent valve 14 is provided at the upper end opening 13 of the vent main body 12 . The valve stem 15 of the vent valve 14 is attached to a support member 16 fixed to the outer surface of the vent main body 12 and extending above the opening 13 so as to be vertically slidable.
A valve element 17 for sealing the opening 13 is fixed to the lower end of the valve stem 15. Further, an adjusting weight 18 is fixed to the upper end of the valve stem 15, and an adjusting coil spring 19 is attached between the weight 18 and the support member 16.

A burner 20 is disposed in the vent body 12 directly below the vent valve 14 facing upward. This burner 20 is fixed to the peripheral wall of the vent main body 12 in a penetrating manner, and a mixture supply pipe 2 connected thereto
1, an electromagnetic valve 22 and a gas/air mixer 23 are provided in order from the burner 20 side. Further, an ignition plug 24 is provided inside the burner 20, and an ignition transformer 25 is connected to the ignition plug 24. The front chamber 10 is provided with a pressure switch 26 which is activated by detecting the pressure inside the furnace, and the electromagnetic valve 22 and the ignition transformer 25 are connected to this pressure switch 26.

The structure of other parts of the atmospheric furnace is similar to that of the conventional one.

The vent valve 14 is adjusted by a weight 18 and a spring 19, and functions to keep the pressure inside the furnace constant.
That is, when the pressure inside the furnace increases during operation, the valve body 17 is pushed up by this pressure, and the valve 14
opens and atmospheric gas is exhausted to the outside. The higher the pressure inside the furnace, the greater the amount of gas discharged, which acts to prevent the pressure from becoming too high. On the other hand, when the intermediate door that was opened as described above is closed and the pressure inside the furnace becomes negative, the pressure switch 26
operates, opens the electromagnetic valve 22, and mixer 23
The air-fuel mixture that has passed through is sent to the burner 20. At the same time, the ignition transformer 25 causes the ignition plug 24 to spark in response to a signal from the pressure switch 26.
Ignite burner 20. This allows burner 2
When the air-fuel mixture is combusted at 0, the combustion exhaust gas discharged from the burner 20 pushes up the valve body 17 due to its pressure and opens the vent valve 14, thereby ensuring an area for suction of the atmosphere and facilitating suction. At the same time, the sucked atmospheric air is used for combustion in the burner 20, and the used atmospheric air is supplied into the furnace. And when the pressure returns,
The pressure switch 26 detects this, closes the electromagnetic valve 22, and stops energizing the spark plug 24. As a result, the burner 20 is extinguished and the vent valve 14 is closed.

In this way, when the pressure inside the furnace becomes negative, the vent valve 14 is forcibly opened to suck in the atmosphere, so the pressure drop is small and the pressure recovers quickly. FIG. 3 shows the fluctuation of the pressure inside the furnace when the intermediate door is opened and closed, and FIG. 3A shows the conventional example, and FIG. When the intermediate door is opened at time A, the pressure in the furnace rises and then remains at a constant value in both cases. When the intermediate door is closed at time B, the pressure inside the furnace decreases.
In the conventional case, the amount of pressure drop is large and C
At this point, the pressure will recover, but it will take some time. On the other hand, in the case of the above embodiment, the amount of pressure drop is small and the pressure recovers quickly at time D. That is, in the case of the above embodiment, pressure fluctuation is smaller and recovery is faster than in the conventional example. Therefore, the amount of atmospheric gas used for pressure recovery can be reduced, for example, to 1/10 to 1/15 of the conventional amount.

In the above embodiment, the burner 20, which uses the sucked atmospheric air for combustion, also serves as a forced opening mechanism for the vent valve 14. However, means other than a burner may be used to open the vent valve.

Effects of the invention According to the intake combustion type exhaust gas vent of this invention,
As mentioned above, when the pressure is negative, atmospheric air is actively sucked to reduce pressure fluctuations and to speed up pressure recovery, and there is no risk of explosion, making it highly safe. Since the pressure recovers quickly, the amount of atmospheric gas consumed is small, and there is no risk of explosion, so there is no need to purge with an inert gas.

[Brief explanation of the drawing]

Fig. 1 is a vertical sectional view of an intake combustion type exhaust gas vent showing an embodiment of this invention, Fig. 2 is an enlarged vertical sectional view of the upper part of the exhaust gas vent of Fig.
The figure is a graph showing fluctuations in furnace pressure, and FIG. 4 is a vertical sectional view of a conventional atmosphere furnace. 10... Front chamber, 11... Exhaust gas vent, 14...
...Vent valve, 20...Burner.

Claims (1)

[Scope of Claim for Utility Model Registration] Vent valve 1, which is an exhaust gas vent installed in the front chamber of an atmospheric furnace that uses flammable atmospheric gas, and is used to maintain a constant pressure inside the furnace.
4 and a burner 20 disposed near the vent valve 14. When the pressure inside the furnace becomes negative, the burner 20 is ignited and the vent valve 14 is opened to suck the atmosphere, and the sucked atmosphere is sent to the burner 20. An intake-combustion type exhaust gas vent that is used for combustion and then supplied to the furnace.