JPH0247412Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a vertical air heater that heats air via a heat exchanger plate using combustion heat.

[Prior art and its problems]

A general air heater is a device that heats air by exchanging combustion heat generated when fluid fuel or the like is combusted via a heat transfer plate that serves as a partition wall.

Multi-tube air heaters are known that use pipes as heat transfer plates and are equipped with a large number of pipes. The surface can easily become overheated and damaged;
There was a problem with poor durability.

In addition, there is Utility Model Publication No. 41-2222 on an air heater using a corrugated metal plate as a heat transfer plate. This air heater has much superior features compared to previous air heaters that used corrugated metal plates. However, since the exhaust gas flow path in this heater is horizontal, it is inevitable that the corrugated metal plate located at the top will be locally overheated due to the buoyancy of the combustion flame, and as above, the durability will be reduced. There were some problems.

On the other hand, in order to solve the above problem, it is usually done to protect the heat transfer surface by introducing dilution air, but this causes another problem of lowering fuel efficiency, and in recent years it has been desired to protect the heat transfer surface. This would go against the current energy-saving measures.

[The purpose of the invention and the means to achieve it]

The present invention takes the above facts into consideration and aims to provide an air heater with excellent durability without reducing fuel efficiency.

In the vertical air heater according to the present invention, a corrugated metal plate formed into a cylindrical shape with grooves oriented in the axial direction is disposed close to the inner wall of an outer cylinder installed vertically,
Inside the corrugated metal plate formed into a cylindrical shape, a fuel combustion device is disposed below, a radiant member whose surrounding wall is in the shape of an inverted truncated cone is disposed above, and a By adopting a structure in which a secondary heat exchanger for preheating the air supplied to the fuel combustion device is installed in the middle of the communicating flue, it is possible to have excellent durability without reducing fuel efficiency. There is.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1 to 3 show an embodiment of the vertical air heater according to the present invention, and in this embodiment, the outer cylinder 10 is mounted on a pedestal suspended from a foundation planted in the floor. It is supported by 12 and arranged upright in a vertical shape. The outer wall of the outer cylinder 10 is covered with a heat insulating material (not shown). The corrugated metal plate 14 is formed into a cylindrical shape with the grooves oriented in the axial direction, and is disposed close to the inner wall of the outer cylinder 10, as shown in FIG. Hereinafter, the corrugated metal plate 14 formed into a cylindrical shape will also be referred to as the cylindrical heat exchanger plate 14.

A fuel combustion device, in this example a burner 16, is disposed inside and below the cylindrical heat exchanger plate 14. The burner 16 includes a burner nozzle 16A and a burner wind box 16B, and has a combustion chamber 18A inside.
It is disposed to fit under a cylindrical case 18 formed with a cylindrical case 18.

A radiation cone 20, which is a radiation member, is disposed above the cylindrical heat exchanger plate 14. The radiation cone 20 is a hollow body composed of walls of a truncated cone 20A at the top, a cylindrical body 20B at the center, and an inverted truncated cone 20C at the bottom, and the upper and lower truncated heads have openings 22A and 22B. It is becoming. Upper opening 22
A communicates with a flue 24 to be described later (in this example, the outer wall of the flue in this part is integrated with the radiation cone 20), and the lower opening 22B communicates with the inside of the cylindrical heat exchanger plate 14. ing. Moreover, the cylindrical body 2 of the radiation cone 20
A plurality of openings 25 are provided on the upper outer periphery of the 0B section. As shown in FIG.
As shown in FIG.

The heated air collection chamber 26 is formed inside an annular wall 28 surrounding the lower outer peripheral wall of the outer cylinder 10 and communicates with the space formed between the outer cylinder 10 and the cylindrical heat exchanger plate 14. There is. The heated air outlet 30 opens in the annular wall 28 . The heated air flow path adjustment chamber 32 has a radiation cone 2 extending from the upper outer circumferential wall of the outer cylinder 10.
It is formed inside an annular wall 34 that surrounds the outer wall of the flue 24 that communicates with the upper opening 22A. The heated air flow path adjustment chamber 32 has an outer cylinder 10 and a cylindrical heat exchanger plate 1, similar to the heated air gathering chamber 26.
It communicates with the space formed between 4 and 4. The heated air inlet 36 opens in the annular wall 34 .

The flue 24 communicating with the upper opening 22A of the radiation cone 20 opens into the atmosphere at its upper end, and a secondary heat exchanger 38 is disposed in the middle thereof. The secondary heat exchanger 38 includes a large number of circular tube groups 42 that cross a flue section 40 . Circular tube group 42
is divided into an upper circular tube group 42A, a central circular tube group 42B, and a lower circular tube group 42C, and each circular tube group is also arranged in a row in the transverse direction of the flue section 40, as shown in FIG. ing.

Both ends of each circular tube constituting the circular tube group 42 are open to the outer wall of the flue section 40. Upper circular tube group 42A
An opening on one end side (right side in FIG. 1) communicates with a combustion air introduction pipe 44. In addition, the lower circular tube group 42C
The opening on the other end side (left side in FIG. 1) communicates with the combustion air outlet pipe 46. Although not shown, the other end of the outlet pipe 46 opens into the burner window box 16B. Central circular tube group 4
The one-end opening of 2B and the one-end opening of lower circular tube group 42C communicate with each other via communication passage 48A, and
The other end side opening of the upper circular tube group 42A and the central circular tube group 4
It communicates with the other end side opening of 2B via a communication passage 48B.

In FIG. 1, reference numeral 50 denotes an expandable and contractible cylindrical body that absorbs thermal strain in the height direction of the outer cylinder 10 and the cylindrical heat exchanger plate 14.

In addition, as the burner nozzle for the fuel combustion burner mentioned above, in this example, an MPC nozzle (Multi-Purpose
Combined Nozzle (product name) is used.

Next, the operation of this embodiment will be explained. The air to be heated is pressurized by a blower (not shown) through piping (not shown) connected to the heated air inlet 36 and reaches the heated air inlet, and then passes through the heated air flow path adjustment chamber 32 and the outer cylinder 10. A predetermined amount of air is supplied through the space formed between the cylindrical heat exchanger plate 14 and the heated air collecting chamber 26, and through piping (not shown) connected from the heated air outlet 30 to the heated air outlet. Supplied to equipment, equipment, etc.

On the other hand, the burner nozzle 1 of the fuel combustion burner 16
From 6A, ultra-atomized fuel is ejected in a wide-angle thin film spray pattern, reacts with oxygen in the preheated combustion air supplied from the burner wind box 16B, and burns in the combustion chamber 18A. do. The combustion gas rises inside the cylindrical heat exchanger plate 14, passes through the openings 22B and 25 of the radiation cone 20, reaches the flue 24, passes through the secondary heat exchanger 38 on the way, and enters the atmosphere from the end opening of the flue. Dissipated.

The combustion gas burned in the combustion chamber passes through the cylindrical heat exchanger plate 14 during the rising process, and is radiated into the outer cylinder 1.
0 and the cylindrical heat exchanger plate 14 is heated. As the combustion gas rises, its temperature decreases due to heat exchange with the heated air, and the amount of radiation decreases. The radiation cone is heated by the combustion gas, and this heat is radiated to the cylindrical heat exchanger plate 14 to compensate for the decrease in the amount of radiation. Heat exchange is also performed to some extent by convection heat transfer at the location where the radiation cone is installed.

The unheated air introduced into the flow path adjustment chamber 32 from the heated air inlet 36 flows from the outer wall of the truncated cone 20A at the upper part of the radiation cone and the outer wall of the flue 24, which constitute the inner wall of the flow path adjustment chamber 32. It is slightly preheated by radiant heat. The heated air that exchanges heat with the combustion gas and gathers in the heated air collection chamber 26 is mixed to become heated air of uniform temperature.

The fuel combustion air is pressurized by a blower (not shown) and introduced from the combustion air introduction pipe 44.
Upper circular tube group 42A, communication passage 48A, central circular tube group 42B, communication passage 48B, lower circular tube group 42C,
The combustion air is discharged from the burner wind box 16B through the combustion air outlet pipe 46. Secondary heat exchanger 38
In this case, since the combustion gas rising in the flue section 40 and the combustion air circulating in each circular tube of the circular tube group 42 exchange heat by convection, the fuel combustion discharged from the burner wind box 16B The air for use is preheated.

This embodiment, which is constructed and operates as described above, has the following advantages.

(1) Since heat is exchanged by radiation heat transfer, heat is transferred evenly to the cylindrical heat exchanger plate, so the cylindrical heat exchanger plate is not locally heated and has high durability.

(2) The vertical shape prevents local overheating due to the buoyancy of the combustion flame, resulting in high durability.

(3) Since the grooves of the corrugated metal plate are arranged in a vertical direction, unburned dust falls without adhering to the inner wall of the cylindrical heat transfer plate, reducing the heat transfer efficiency of the heat transfer surface. Never. In addition, it is easy to collect unburned soot and dust.

(4) Since a secondary heat exchanger is installed to preheat the combustion air, the combustion temperature increases accordingly, and the reaction between fuel particles and oxygen in the air becomes faster, resulting in combustion in a shorter time. As a result, the amount of unburned dust generated is suppressed. Therefore, the combustion efficiency is increased and the amount of unburned dust emitted into the atmosphere is reduced, which is effective in preventing pollution, and the amount of unburned dust remaining inside the cylindrical heat exchanger plate is reduced. Equipment maintenance is simplified.

(5) The circular tubes of the secondary heat exchanger are located in the flue and act as a resistance to passage of combustion gas, so the combustion air is supplied under pressure, preventing cold air from entering from outside. combustion reaction is promoted. Furthermore, since the amount of air can be adjusted and supplied in accordance with the amount of combustion, low air ratio combustion is possible.

(6) Since the radiation cone is provided, it is possible to heat the relatively low temperature area above the cylindrical heat exchanger plate.

(7) Since the MPC nozzle is used, the fuel is ultra-atomized and sprayed in a wide-angle thin layer, increasing the contact area between the fuel and air and completing combustion in a short time, almost reaching the theoretical value. It is possible to achieve combustion at a low air ratio close to that of the previous model, and the thermal energy required to exhaust excess air at a high temperature can be saved. Furthermore, since the ejected particles are small, the amount of unburned dust generated is also reduced.

[Effect of idea]

As explained above, the air heater according to the present invention has the effect of simultaneously achieving high fuel efficiency and excellent durability.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the vertical air heater according to the present invention, FIG. 2 is a sectional view taken along the line A-A in FIG. 1, and FIG. 3 is a B-- It is a sectional view taken along the line B. 10... Outer tube, 14... Cylindrical heat transfer plate, 16...
Burner, 20... Radiation cone, 24... Flue, 2
6... Heated air collection chamber, 32... Heated air flow path adjustment chamber, 38... Secondary heat exchanger.

Claims (1)

[Scope of utility model registration request] Close to the inner wall of the vertically installed outer cylinder,
A corrugated metal plate formed into a cylindrical shape with grooves oriented in the axial direction is disposed, and inside the corrugated metal plate formed into a cylindrical shape, a fuel combustion device is installed below and a lower peripheral wall is installed above. A radiant member in the shape of an inverted truncated cone is provided, and a secondary heat exchanger for preheating the air supplied to the fuel combustion device is provided in the middle of a flue communicating with the inside of the radiant member. This vertical air heater is characterized by: