JPS6252201B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heating furnace, and more particularly to a temperature control device for a fluid flowing through heat transfer tubes installed in the furnace.

When it is necessary to adjust the temperature of multiple fluids in a heating furnace, the temperature of one fluid can be adjusted by increasing or decreasing the combustion capacity in the combustion device, but the temperature of other fluids cannot be adjusted by increasing or decreasing the combustion capacity. .
In order to control the temperature in such a case, the conventional method shown in FIG. 1 has been taken.

That is, a burner 3 to which a fuel pipe 2 is connected is installed below the heating furnace main body 1, and a damper 4 is installed above.
An exhaust pipe 5 is formed in which the exhaust pipe 5 is equipped. Heat exchanger tubes 6 and 7 are installed at the upper and lower sides of the furnace, respectively, and the fluid flowing through each of the heat exchanger tubes 6 and 7 is heated by combustion in the burner 3 and then flows outside the furnace. is taken out.

The temperature of the fluid flowing through the heat transfer tube 7 disposed on the burner 3 side is adjusted by detecting its outlet temperature and adjusting the combustion capacity with a fuel control valve 8 attached to the fuel pipe 2. On the other hand, the fluid flowing through the heat transfer tube 6 which is piped away from the burner 3 is controlled by the fluid control valve 1 attached to the bypass pipe 9.
0, the unheated fluid flowing through the bypass pipe 9 was mixed with the high-temperature fluid heated through the furnace to adjust the temperature of the fluid.

However, with such means, there is a considerable temperature difference between the fluid flowing through the bypass pipe 9 and the fluid coming out through the furnace, so there is a local temperature difference in the part of the heat transfer tube 6 that joins the bypass pipe 9. A thermal shock or thermal stress occurs, which may shorten the useful life of the heat exchanger tubes 6 or cause an accident due to damage to the heat exchanger tubes 6. Furthermore, the above-mentioned structure was complicated and caused problems in terms of maintenance.

An object of the present invention is to provide a fluid temperature control device for a heating furnace that eliminates the above-mentioned drawbacks of the prior art, allows easy fluid temperature control, expands the adjustable temperature range, and does not cause damage to heat transfer tubes. It is on offer.

To achieve this objective, the present invention provides a heating furnace body, a burner installed at a predetermined position in the heating furnace body, an exhaust pipe communicating with the heating furnace body, and a burner located in the heating furnace body away from the burner. For example, a cylindrical radiation heat shield is placed at a location to block most of the radiant heat from the burner flame and form a convection heat transfer section between it and the furnace wall, and the flow rate of combustion gas flowing through the convection heat transfer section is adjusted. a first heat transfer tube on the upstream side in the flow direction of the combustion gas heated by radiated heat from the burner; and a combustion tube disposed in the convection heat transfer section and heated by convection heat transfer. and a second heat transfer tube on the downstream side in the gas flow direction.

Then, by adjusting the gas flow rate of the convection heat transfer section by the gas flow rate adjustment means, the second
The heat exchanger tube is characterized in that the temperature of the fluid flowing inside the heat exchanger tube can be adjusted separately from that of the first heat exchanger tube.

Embodiments of the present invention will be described below with reference to FIG.

The heat transfer tube 7 is installed near the burner 3 as in the conventional case, and the outlet temperature of the fluid flowing through the heat transfer tube 7 is detected and the fuel control valve 8 attached to the fuel pipe 2 is operated.
The temperature is regulated by adjusting the combustion capacity. Burner 3 in the flow path of combustion gas coming out of burner 3
(above burner 3 in the drawing),
A flow rate adjusting cylinder 11 is installed. The flow rate adjusting cylinder 11 has openings 12, 12 at both ends, and a flow rate variable part 13 consisting of a damper or the like is provided in one of the openings 12, and the flow rate variable part 13 controls the amount of combustion gas passing through the cylinder interior 14. can be adjusted. Flow rate adjustment cylinder 1
1 is fixed at a predetermined distance from the furnace wall 15 of the heating furnace body 1, and connects the flow rate adjusting cylinder 11 and the furnace wall 1.
5, a convection heat transfer section 16 is formed by substantially shielding the flame radiation heat 17 from the burner 3, and a heat transfer tube 6 is wound around the convection heat transfer section 16 so as to surround the flow rate adjusting cylinder 11. has been done. Therefore, the heat transfer tube 6 is arranged in parallel with the flow rate adjustment cylinder 11, and both the flow rate adjustment cylinder 11 and the convection heat transfer section 16 communicate with the exhaust pipe 5.

The temperature of the fluid flowing through the heat transfer tube 6 is adjusted by detecting its outlet temperature and indirectly adjusting the flow rate of the combustion gas flowing through the convection heat transfer section 16 using the flow rate adjustment cylinder 11. That is, when the flow rate variable portion 13 of the flow rate adjustment cylinder 11 is opened, the amount of combustion gas flowing through the cylinder interior 14 increases, thereby reducing the amount of combustion gas flowing through the convection heat transfer portion 16, and the convection heat transfer rate decreases. As a result, the temperature of the fluid flowing through the heat transfer tubes 6 decreases. When increasing the temperature of the fluid, use the flow rate adjustment cylinder 1
If the flow rate variable section 13 of No. 1 is closed and the amount of combustion gas flowing through the convection heat transfer section 16 is increased, the convection heat transfer rate will increase and the temperature of the fluid will rise. By varying the flow rate of the combustion gas with the flow rate adjusting cylinder 11 in this way, the temperature of the fluid flowing through the heat transfer tubes 6 can be adjusted.

The present invention can be applied to round-shaped furnaces, square-shaped furnaces, etc., and can be applied not only to spiral-shaped heat exchanger tubes as shown in Fig. 2, but also to comb-shaped heat exchanger tubes or heat exchanger tubes that are a combination of the above two. It can also be used.

As described above, the present invention relates to a heating furnace in which heat transfer tubes are placed in a furnace where the ambient temperature is extremely high and heat transfer efficiency is high.In this type of heating furnace, the heat transfer tubes placed near the burner are By adjusting the amount of fuel supplied to the fluid, the fluid temperature can be easily adjusted. However, if the heat transfer tube is located far from the burner, it is impossible to directly finely adjust the fluid temperature even if the amount of fuel supplied to the burner is controlled.

Conventionally, therefore, the temperature of the heat exchanger tubes 6 has been adjusted using a configuration as shown in FIG. 1, but this has had various technical problems as described above.

Therefore, the present invention disposes a radiant heat shield at a position away from the burner in the heating furnace main body, which blocks radiant heat from the burner and forms a convection heat transfer section between the furnace wall and the furnace wall, where the temperature can be easily adjusted. A second heat transfer tube is provided in the convection heat transfer section, and a gas flow rate adjusting means for adjusting the flow rate of combustion gas flowing through the convection heat transfer section is provided, and the second heat transfer is achieved by adjusting the gas flow rate. It adjusts the temperature of the fluid flowing inside the heat tube.

Therefore, heat can be efficiently transferred from the high-temperature combustion gas, fine temperature adjustment can be easily and reliably performed, and the temperature adjustment range can be expanded. Furthermore, since the temperature can be adjusted within the furnace, there is no need to apply thermal shock or thermal stress to the heat exchanger tubes as in conventional methods, and the service life of the heat exchanger tubes can be extended. Moreover, the structure is simple,
Easy to maintain.

[Brief explanation of the drawing]

FIG. 1 is a cutaway front view of a conventional heating furnace, and FIG. 2 is a cutaway front view of a heating furnace according to an embodiment of the present invention. 1... Heating furnace body, 3... Burner, 6, 7...
Heat exchanger tube, 11...Flow rate adjustment cylinder, 12...Opening,
13...Flow rate variable section, 14...Cylinder interior, 16...Convection heat transfer section, 17...Flame radiation heat.

Claims (1)

[Scope of Claims] 1. A heating furnace body, a burner installed at a predetermined position in the heating furnace body, an exhaust pipe communicating with the heating furnace body, and a part located away from the burner in the heating furnace body. a radiant heat shield that substantially shields radiant heat from the burner flame and defines a convection heat transfer section between it and the furnace wall; a gas flow rate adjustment means that adjusts the flow rate of combustion gas flowing through the convection heat transfer section; A first heat transfer tube on the upstream side in the flow direction of the combustion gas heated by flame radiation heat from the burner, and a first heat transfer tube on the downstream side in the flow direction of the combustion gas disposed in the convection heat transfer section and heated by convective heat transfer. and a second heat transfer tube, and by adjusting the gas flow rate of the convection heat transfer section by the gas flow rate adjusting means, the temperature of the fluid flowing in the second heat transfer tube is set separately from that of the first heat transfer tube. A heating furnace configured to be adjustable. 2. The heating furnace according to claim 1, wherein the radiation heat shield is made of a cylinder having openings at both ends, and the gas flow rate adjusting means is provided within the radiation heat shield. 3. The heating furnace according to claim 1, wherein the radiation heat shield is fixed to a heating furnace main body, and the second heat transfer tube is wrapped and supported around the radiation heat shield. . 4. In claim 1, a fuel supply amount adjusting means is attached to the fuel pipe connected to the burner, and the temperature of the fluid flowing in the first heat transfer tube is adjusted by the fuel supply amount. A heating furnace characterized by being configured as follows.