JPH0749224Y2 - Exhaust RX gas combustion device - Google Patents

Description

[Detailed Description of the Invention] (Industrial field of application) The present invention is an exhaust RX gas used for temperature control of an atmosphere heat treatment furnace, in which combustible gas generated from an atmosphere heat treatment furnace is burned for effective use. It relates to a combustion device.

(Prior art) In the atmospheric heat treatment, the atmosphere heat treatment furnace is filled with an atmosphere gas such as an oxidizing gas, a reducing gas, an inert gas, or a carburizing gas according to the purpose, and the temperature of the atmosphere gas is adjusted by a heat radiation tube. It is done while adjusting.

A flammable gas (hereinafter referred to as RX gas) is used in this atmosphere gas as in the case of carburizing.

FIG. 5 shows a conventional burner that burns and reuses RX gas. The burner has a U-shaped heat radiating tube 1, which penetrates the wall surface of the atmosphere heat treatment furnace 2 and is inserted into the RX gas in the furnace 3. And the nozzle 5
Exhaust RX from the nozzle 7 by the jet ectoair sent from the
Gas is sucked and fuel gas is supplied from the nozzle 6 and burned by the combustion air supplied from the nozzle 8.
This fuel is carried in the heat dissipation tube 1. 10 is the flame. Further, the combustion gas flows in the U-shaped radiator pipe 1 in the direction of the arrow and is exhausted from the duct 11 through the exhaust pipe 12.

FIG. 4 shows a single-ended radiant tube burner generally used in an atmospheric heat treatment furnace, which is not designed to burn exhaust RX gas.

This burner is provided with a combustion gas combustion pipe 13 and a fuel gas combustion air pipe 14 concentrically to form a fuel gas air passage 15, and a heat exchange chamber inner pipe 17 is provided outside the fuel gas combustion air pipe 14. The outer pipe 16 is provided concentrically to form a heat exchange chamber 18 and an air chamber 19. Reference numeral 20 is a heat transfer tube provided in the heat exchange chamber 18, and is provided so as to connect the air chamber 19 and the fuel gas air passage 15 to each other.

The fuel gas is supplied from the nozzle 21 into the fuel gas combustion pipe 13, mixed with the air supplied to the fuel gas air passage 15, and burned in the radiant tube inner cylinder 22. The combustion gas reverses at the end of the radiant tube inner cylinder 22 and flows in the combustion gas 24 formed with the radiant tube outer cylinder 23 in the direction of the arrow. Then, this combustion gas exchanges heat with the air supplied from the nozzle 25 and flowing in the heat transfer tube 20 in the heat exchange chamber 18, and the temperature of the air is raised and flows into the fuel gas air passage 15, The combustion gas is cooled and is exhausted from the exhaust pipe 27 together with the air from the ejector nozzle 26.

In addition, the Radiant tube inner cylinder 2 due to the effect effect
2. The inside of the outer cylinder 23 has a negative pressure, the fuel gas is sucked from the nozzle 21 and the air is sucked from the nozzle 25, and the fuel gas, the air and the combustion gas flow as shown by arrows.

(Problems to be Solved by the Invention) In the conventional burner shown in FIG. 5, the combustion gas burned in the radiating pipe 1 is exhausted as it is, so the thermal energy of the combustion gas is effectively used. There was a problem that the thermal efficiency was low.

In the atmosphere heat treatment furnace, a pure
Since RX gas must be used, inconvenience arises when the heat radiating pipe 1 with a large heat load is burned out and the combustion gas leaks.

Therefore, when a hole is opened in the heat dissipation tube 1 of the flame 10 where the heat load is highest, the burner needs to be replaced, and the service life is short.

In order to extend this service life as much as possible, the radiation tube 1 must be thickened to reduce the load on the combustion chamber.
When the load on the combustion chamber is reduced in this way, the amount of heat radiation of the heat radiation tube 1 is reduced and the number of heat radiation tubes must be increased. Further, since the heat radiation tube 1 is thick and U-shaped, the furnace of the atmospheric heat treatment furnace Since the mounting area of the burner mounted through the wall becomes large, the atmosphere heat treatment furnace becomes large. As a result, extra heat energy for adjusting the temperature of the atmosphere heat treatment furnace and RX gas are consumed, which causes problems in energy saving and resource saving.

Next, the burner shown in FIG. 4 exchanges heat between the combustion gas and the combustion air to effectively utilize the retained heat of the combustion gas, namely, the radiant tube inner cylinder 22 and the radiant tube outer cylinder 23. The double structure makes it possible to prevent the combustion gas from leaking into the atmosphere heat treatment furnace to extend the service life even if the radiant tube 22 that plays a role in the combustion chamber has a hole. Combined, the inner tube of the radiant tube
22 is thin, the load on the combustion chamber is high to increase the amount of heat radiated from the outer tube of the radiant tube, and the atmosphere heat treatment furnace is downsized. Therefore, the problem of the thermal efficiency of the burner shown in Fig. 5 The problems of energy saving and resource saving have been solved.

However, since the burner shown in FIG. 4 was burned and disposed of in a place other than the atmosphere heat treatment furnace without effectively using the exhaust RX gas, the heat retained in the exhaust RX gas and the RX gas were wasted, There are still problems in terms of energy saving and resource saving.

Further, there is a problem that a combustion facility for combusting the exhaust RX gas is required, and the combustion environment is heated because the combustion is performed outside the furnace, and the work environment is deteriorated.

The present invention effectively utilizes exhaust RX gas and its retained heat,
Further, it is intended to provide an exhausted RX gas combustion device which improves the thermal efficiency, saves energy and resources, and improves the working environment.

(Means for Solving the Problems) The means for solving the above problems is a fuel gas combustion air tube, an RX gas combustion tube, and an RX tube which are sequentially concentrically formed around a fuel gas combustion tube. A gas combustion air pipe is provided to concentrically form a fuel gas passage, a fuel gas combustion air passage, an RX gas passage, and an RX gas combustion air passage. And the RX
The exhaust gas heat exchange chamber is formed by concentrically providing a heat exchanger outer shell on the outside of the gas combustion air pipe, and the exhaust gas heat exchange chamber is connected to the exhaust gas heat exchange chamber and the exhaust gas heat exchange chamber is penetrated by RX.
Connect the RX gas combustion air nozzle to the gas combustion air passage.

On the other hand, an RX gas heat exchange chamber is provided which communicates with the RX gas passage by penetrating the outer shell for heat exchanger and the RX gas combustion air pipe, and the fuel gas combustion air passage is penetrated through the RX gas heat exchange chamber. With an air nozzle for fuel gas combustion that communicates with
Connect the RX gas supply nozzle to the RX gas heat exchange chamber.

Then, a radiant tube inner cylinder is provided so as to be connected to the RX gas combustion air tube, the radiant tube outer cylinder is covered concentrically with the radiant tube inner cylinder, and the end of the radiant tube outer cylinder is used for the heat exchanger. It is connected to the outer torso.

(Function) With this configuration, the ejector sucks the fuel gas from the fuel gas supply nozzle into the fuel gas combustion pipe,
The fuel gas combustion air is sucked from the fuel gas combustion air nozzle into the fuel gas combustion air furnace, and the RX in the atmosphere heat treatment furnace
The gas is sucked from the RX gas supply nozzle through the RX gas heat exchange chamber into the RX gas passage, and the RX gas combustion air is sucked from the RX gas combustion air supply nozzle into the RX gas combustion air passage, and the fuel gas and RX gas burns in the radiant tube.

This combustion gas reverses at the end of the radiant tube inner cylinder and reaches the exhaust gas heat exchange chamber through the annular gap between the radiant tube inner cylinder and the radiant tube outer cylinder.
Exhausted by EDGE.

In this series of flows, the fuel gas combustion air receives heat in the RX gas heat exchange chamber and also receives heat between the fuel gas air passage and the RX gas passage to raise the temperature, effectively utilizing the heat retained by the RX gas. To do.

On the other hand, the retained heat of the exhaust gas exchanges heat with the RX gas combustion air in the exhaust gas heat exchange chamber to radiate heat, and the RX gas combustion air receives heat and rises in temperature. The heat of the exhaust gas received by the RX gas combustion air is sequentially transferred to the RX gas, the fuel gas combustion air, and the fuel gas flowing in the concentric flow paths.
In particular, since RX gas exchanges heat with the fuel gas combustion air to lower the temperature, it receives the heat of the exhaust gas and rises in temperature.
The temperature difference between the RX gas combustion air and the air becomes larger, and heat transfer becomes more active, which promotes the recovery of the heat retained in the exhaust gas.

Also, since the radiant tube inner cylinder and the radiant tube outer cylinder have a double structure, even if there is a hole in the radiant tube inner cylinder that has a high heat load, the combustion gas does not leak from the radiant tube outer cylinder to the outside. Even if there is a hole in the outer tube of the radiant tube, since the inside of the burner has a negative pressure due to the engineer, the combustion gas will not leak to the outside. As a result, the radiant tube inner cylinder and the outer cylinder can be made as thin as possible, and the amount of heat radiation from the radiant tube outer cylinder is improved.

(Embodiment) An embodiment of the present invention will be described in detail below. In FIG. 1, a fuel gas combustion air tube 14, a RX gas combustion tube 29, and an RX tube are sequentially concentrically arranged around the fuel gas combustion tube 13 as a center.
A gas combustion air pipe 28 is provided, and the fuel gas passage 33, the fuel gas air passage 32, the RX gas passage 31, and the RX gas combustion air passage 30 are provided.
Are formed concentrically as shown in FIG. Reference numeral 34 is a swirl vane provided at the outlet of the flow path. In order to make the diameter of the radiant tube inner cylinder 22 as small as possible to increase the load on the combustion chamber, between the end of the radiant tube inner cylinder 22 and the ends of the RX gas combustion air tube 28 and the RX gas combustion tube 29. A guide cylinder 25 for guiding the RX gas and the RX gas combustion air into the radiant tube inner cylinder 22 is provided between the two. Further, the radiant tube inner cylinder 22 is concentrically covered with a radiant tube outer cylinder, and its rear end is closed by a cover plate 23 ', and the rear end of the radiant tube inner cylinder 22 and the cover plate 23' are covered. Combustion gas flow paths 24 are formed so as to be separated from each other and to allow the combustion gas to be reversed as indicated by an arrow. 35
Is a straightening plate provided in the combustion gas reversal section as shown in FIG. Reference numeral 36 denotes a heat exchanger outer shell provided concentrically outside the RX gas combustion air tube 28, and is a radiant tube outer cylinder.
The exhaust gas heat exchange chamber 37 is formed by connecting the ends of 23. The exhaust gas heat exchange chamber 37 is within the length range of the RX gas combustion air pipe 28, and not within the length range of the heat exchanger outer shell 36. Reference numeral 37 'denotes an exhaust gas duct connected to the heat exchanger outer shell 36. And the contact with the RX gas combustion air is increased, and as much heat as possible of the exhaust gas is recovered to the RX gas combustion air. Reference numeral 39 is an ejector connected to the exhaust gas duct 37 '. 40 is an outer shell for heat exchanger 36 and
The RX gas heat exchange chamber is provided so as to penetrate the RX gas combustion air passage 30 and communicate with the RX gas passage 31. 41 is this RX
The fuel gas combustion air nozzle is provided so as to penetrate the gas heat exchange chamber 40 and communicate with the fuel gas air passage 32.
Reference numeral 42 is an RX gas supply nozzle connected to the RX gas heat exchange chamber 40. Reference numeral 21 is a fuel gas supply nozzle provided in communication with the fuel gas passage 33. Reference numeral 43 is a spark plug inserted in the fuel gas passage 33.

Next, in FIG. 3, air is supplied from the air source pipe 54 to the ejector 39, the RX gas combustion air supply nozzle 38 and the fuel gas combustion air nozzle 41 through the butterfly valves 46, 47 and 48, respectively. It has become so. Reference numeral 53 denotes a fuel gas pipe such as butane gas, which is adapted to supply the fuel gas to the fuel gas supply nozzle 21 via the electromagnetic valve 44. Reference numeral 56 is an RX gas pipe for sucking the RX gas in the atmosphere heat treatment furnace, and is adapted to supply the RX gas to the RX gas supply nozzle 42 via the orifice 51, the solenoid valve 50, and the ejector 49. Reference numeral 55 is an air pipe for the engine controller 49, and 52 is a control motor valve.

The operation of the present embodiment configured as above will be described below. First, the operation of the exhaust RX gas combustion device will be described with reference to FIG. 3. The opening of the butterfly valve 47 is controlled according to the load of the atmosphere heat treatment furnace to control the opening of the burner (radiant tube outer cylinder 23) by the ejector 39. Control the pressure,
The amount of fuel gas from the fuel gas pipe 53 is controlled. At the same time, RX gas is sucked from the RX gas pipe 56. This RX gas amount is limited to a fixed amount by the orifice 51. The amount of each air is controlled by the butterfly dampers 46 and 48.
Also, when the suction force by the ejector 39 is insufficient at a low load, etc. and the suction of the RX gas is insufficient, the opening degree of the control motor valve 52 is controlled to control the amount of air sent to the ejector 49. Control the suction force to ensure RX gas suction.

During normal operation, the fuel gas is constantly burned to maintain the temperature in the atmosphere heat treatment furnace,
For the RX gas, the solenoid valve 50 is closed when the internal pressure of the atmosphere heat treatment furnace drops, for example, when the product is loaded and unloaded by opening the door of the atmosphere heat treatment furnace to prevent the outside air from entering the atmosphere furnace. When an emergency occurs, the solenoid valves 44 and 45 are closed to stop the operation.

Next, the operation of the combustion apparatus itself will be described with reference to FIG. 1. The fuel gas sucked into the fuel gas passage 33 is mixed with the air supplied to the fuel gas air passage 32 and is constantly radiant tube inner cylinder 22. Burns inside. On the other hand, the RX gas sucked into the RX gas passage 31 mixes with the air supplied to the RX gas combustion air passage 30, and is ignited and burned by the combustion of the fuel gas that is constantly burning. This combustion gas is radiant tube inner cylinder
It reverses at the rear end of 22, and is evenly distributed in the combustion gas passage 24 by the flow regulating plate 35 and flows in the direction of the arrow. Then, in the exhaust gas heat exchange chamber 37, heat exchange is performed by the counterflow between the combustion gas and the air flowing in the RX gas combustion air passage 30. The heat of the RX gas combustion air thus received is transferred to the RX gas, the fuel gas combustion air and the fuel gas flowing through the concentric flow paths.

On the other hand, the RX gas flowing into the RX gas heat exchange chamber 40 from the RX gas supply nozzle is cooled by the air flowing in from the fuel gas combustion air nozzle 41 to lower the temperature, and the air receives heat and rises in temperature.

By this temperature drop of the RX gas, the temperature gradient is increased in the heat exchange between the RX gas combustion air and the RX gas to improve the heat exchange efficiency, and the heat retained in the exhaust gas is recovered more efficiently.

The exhaust gas thus dissipated in the exhaust gas heat exchange chamber 37 is further heat-exchanged with the air flowing in the RX gas combustion air supply nozzle 38 in the exhaust gas duct 37 ′, and the ejector 39
Is sucked and discharged.

On the other hand, regarding the leakage of fuel gas, the radiant tube inner cylinder 22 and the radiant tube outer cylinder 23 have a double structure, and the inside of the radiant tube outer cylinder 23 is under negative pressure. Even if there is a hole in the atmosphere, there is no leakage into the atmosphere heat treatment furnace. Combined with this, make the radiant tube inner cylinder 22 as thin as possible,
It is possible to increase the load of the combustion chamber that burns in the radiant tube inner cylinder 22, and it is possible to increase the amount of heat radiation from the radiant tube outer cylinder 23.

(Effect of the Invention) As described in detail above, according to the present invention, the fuel gas combustion air passage, the RX gas combustion passage, and the RX gas combustion combustion air passage are sequentially formed concentrically around the fuel gas passage. An exhaust gas heat exchange chamber is provided on the outer periphery of the exhaust air pipe, and the RX that communicates with the RX gas passage through the outer shell for the heat exchanger and the RX gas combustion air pipe.
A gas heat exchange chamber was provided to lower the temperature of the RX gas by the fuel gas combustion air, so the temperature between the RX gas combustion air that is heated by receiving heat from the exhaust gas and the temperature of the RX gas that is being cooled. The gradient can be increased to improve the heat recovery efficiency of exhaust gas.

Also, since the radiant tube inner and outer cylinders have a double structure and the radiant tube outer cylinder has a negative pressure inside, it is possible to perform atmospheric heat treatment even if the radiant tube has holes in the inner and outer cylinders. There is no leakage of combustion gas into the furnace.

Therefore, the service life can be extended, the radiant tube inner cylinder can be made thin to increase the load on the combustion chamber, and the heat radiation efficiency from the radiant tube outer cylinder can be improved.

As a result, the atmosphere heat treatment furnace is downsized, the RX gas usage fee and heat energy consumption are reduced, and the exhaust gas heat recovery and
By reusing RX gas, energy saving and resource saving can be achieved.

[Brief description of drawings]

1 is a vertical sectional view of an embodiment of the present invention, FIG. 2 is a vertical sectional view taken along the line AA of FIG. 1, FIG. 3 is a valve tube diagram for the embodiment of FIG. 1, and FIG. Is a vertical cross-sectional view of a conventional example, and FIG. 5 is a vertical cross-sectional view of a conventional burner equipped with RX gas combustion. 13 …… Fuel gas combustion pipe 14 …… Fuel gas combustion air pipe 22 …… Radiant tube inner cylinder 23 …… Radiant tube outer cylinder 28 …… RX gas combustion air pipe 29 …… RX gas combustion pipe 30… … RX gas combustion air passage 31 …… RX gas passage 32 …… Fuel gas air passage 33 …… Fuel gas passage 36 …… Heat exchanger outer shell 37 …… Exhaust gas heat exchange chamber 38 …… RX gas combustion air Supply nozzle 39 …… Egyakuta 40 …… RX gas heat exchange chamber 41 …… Fuel gas combustion air nozzle 42 …… RX gas supply nozzle

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display area F23G 7/06 ZAB

Claims (1)

[Scope of utility model registration request] 1. A fuel gas combustion pipe, a fuel gas combustion air pipe, an RX gas combustion pipe, and an RX gas combustion air pipe are sequentially provided in a concentric manner, and the fuel gas passage and the fuel gas are burned in a concentric manner. Forming an exhaust gas heat exchange chamber by forming a heat exchanger outer shell in a concentric manner on the outside of the RX gas combustion air pipe, and forming an exhaust air passage, an RX gas passage and an RX gas combustion air passage. The exhaust chamber is connected to the exchange chamber, the exhaust gas heat exchange chamber is penetrated, and the RX gas combustion air nozzle is connected to the RX gas combustion air passage, while the heat exchanger outer shell and RX gas combustion air pipe are penetrated. And an RX gas heat exchange chamber that communicates with the RX gas passage, and a fuel gas combustion air nozzle that penetrates the RX gas heat exchange chamber and communicates with the fuel gas combustion air passage.
RX gas supply nozzle is connected to the gas heat exchange chamber, a radiant tube inner cylinder is provided so as to be connected to the RX gas combustion air pipe, and a radiant tube outer cylinder is covered concentrically with respect to the radiant tube inner cylinder, and the radiant tube An exhaust RX gas combustion device, characterized in that an end portion of a tube outer cylinder is connected to the outer shell for a heat exchanger.