JPS5842834Y2 - Forced air heater - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a forced-air heater having a heat exchanger constituted by a plurality of pipes through which combustion gas generated in a burner section passes.

It is generally known that fuel gas contains sulfur (element symbol S), which is caused by moisture (H
2O) and S cause a chemical reaction (the following formula) % Formula % () The dew point of these (sulfite) sulfuric acids changes depending on the volume ratio in the gas, but in general city gas it is 80 to 120°C.

In addition, the temperature range where (sulfite) sulfuric acid causes severe metal oxidation corrosion is 80°C.
~100℃, and this temperature range includes the downstream side of the heat exchanger (near the connection with the downstream header) and the downstream header, and if these are metal plates, they will corrode and the holes will become obvious. This may cause cracks or cracks, causing exhaust gas to leak.
life ends.

Particularly when such a heat exchanger header or the like is incorporated into a closed hot air heater, exhaust gas may leak into the room or drain may leak from the holes.

The present invention was developed in view of the above circumstances, and its purpose is to provide an improved forced air heater that prevents the temperature of the downstream side of the heat exchanger, the downstream header section, etc. from falling below the dew point temperature. It is something to do.

Therefore, in this idea, a header is provided at the downstream end of the multiple pipes that make up the heat exchanger to collect the combustion gas from each pipe, so that part of the header is not air-cooled more than necessary. The specific structure is to prevent the header from being directly hit by the air flow from an indoor blower, and to further provide a windproof member with lower thermal conductivity than the header.

With this configuration, this invention can prevent parts of the header from corroding when the temperature drops below the dew point, and extend the lifespan of the heat exchanger and part of the header, thereby extending the lifespan of forced air heaters. It has the effect of being able to

Next, one embodiment of this invention will be explained with reference to the drawings.

In Figures 1 to 5, 1 is a combustion tube, 2 is a header connected to this combustion tube on the downstream side, and 3 is a header connected to this header on the downstream side, parallel to each other and also connected to the combustion tube 1. Multiple parallel metal heat exchanger pipes, 4
is an auxiliary header connected to the heat exchanger pipe on the downstream side, 5 is an exhaust pipe connected to the auxiliary header on the downstream side, 6 is an air supply/exhaust attachment connected to the exhaust pipe on the downstream side, Reference numeral 7 denotes a baffle plate provided in the combustion tube 1 to allow sufficient heat exchange between the high-temperature gas and the wall of the combustion tube 1.

A burner 8 is provided in the combustion tube 1 and is composed of a plurality of pipe-shaped burner elements 8a.

9 is a blower for indoor ventilation, and its output air flows as shown by arrow B, exchanges heat with the combustion tube 1 and heat exchanger 3, becomes high-temperature air, and is sent from the indoor ventilation grill (not shown) to the machine. Sent outside (indoors).

10 is a motor for driving the blower 9, and 11 is a gas chamber communicating with the burner 8, which is filled with combustion gas.

12 is a primary air hole bored in a part of this gas chamber; 13
Reference numeral 1 denotes an air supply hose communicating with the air supply path of the supply/exhaust attachment 6, and 14 represents combustion air passing through the air supply hose, which is generally obtained from outside.

15 is the exhaust joint, 16 and 17 are the heat exchanger pipes 3
The inner fin is made by twisting a flat metal plate.

18 is a forced air blower that sends air for combustion; S is an air passage leading from the air supply hose 13 to the exhaust pipe 5; 19 is the main body casing; and 20 is the air provided above the exhaust pipe 5 in the main body casing 19. The guide 21 is a blower casing, and 22 is a windproof member, which prevents the air flow from the indoor blower 9 from directly hitting the header 4 and the vicinity of the downstream end of the heat exchange pipe 3. Poor thermal conductivity.

22a is a recess formed in the lower part of the windproof member 22, and accommodates a portion (lower end in the figure) of the header 4 located upstream with respect to the indoor air flow.

22b is a windbreak plate constituting the main part of the windbreak member 22;
2C is a mounting leg for attaching this windbreak plate to the header 4.

Next, the operation of the one shown in FIG. 2 will be explained.

When a starting switch (not shown) is turned on, the blower 19 is activated and combustion air flows as shown by arrow A.
Combustion gas is supplied from the gas chamber 11 to the burner 8 section, and combustion is performed within the combustion tube 1.

After the start of combustion, when the internal temperature rises to a certain extent, the indoor ventilation motor 10 is activated, and the warm air that has exchanged heat with the combustion tube 1 and the heat exchanger 3 is transferred to the indoor ventilation grill (not shown) by the blower 9. ) is sent into the room, and the cool air in the room is sucked into the inside of the machine by the blower 9, and then sent out as described above.

At this point, the combustion gas that has been cooled to a certain extent by the combustion tube 1 is collected in the header 2, but the temperature in this part is still high and there is no risk of dew point corrosion.

However, for heat exchange in the medium to low temperature range, that is, heat exchange downstream of header 2, the contact area with the heat exchange air is increased, so it is better to use a shell-and-tube heat exchanger because the amount of heat exchange is It would be better if the number of heat exchange pipes increased, but on the other hand, each heat exchange pipe 3
The combustion gas that has passed through the header 4 is cooled to a considerably low temperature, and if the windproof member 22 were not used, the temperature would be below the dew point.

This also applies to the end of the heat exchange pipe 3 on the header 4 side.

However, by providing the windbreak member 22, the airflow from the indoor blower is directed to the header 4 and the header 4 of the heat exchange pipe 3.
This prevents direct contact with the side edges and prevents heat exchange with the low-temperature air in that area.
The header 4 and the end of the heat exchange pipe 3 on the header 4 side) are prevented from becoming below the dew point temperature.

As mentioned above, this idea at least prevents the airflow from an indoor blower from directly hitting the header that collects the combustion gas that has passed through the heat exchange pipe, and also provides a windproof member that has lower thermal conductivity than the header. This has the effect of greatly reducing the amount of heat removed by air blowing, suppressing as much as possible corrosion of a part of the header due to a temperature below the dew point, and providing a forced air heater with a long life.

[Brief explanation of the drawing]

The figures all show one embodiment of this invention; Fig. 1 is a front view showing a schematic configuration, Fig. 2 is a front view showing a section of the heat exchanger part in Fig. 1, and Fig. 3 is a front view showing a schematic configuration. A front view showing an enlarged view of the heat exchanger pipe in Fig. 2, and Fig. 4 as Fig. 3 IV-
Vertical side view of the cross section taken along the IV line in the direction of the arrow, No. 5
The figure is a side view showing a schematic configuration. In the figure, 1 is a combustion tube, 3 is a heat exchange pipe, 8 is a burner, 9 is an indoor blower, 16.17 is an inner fin, 18 is a combustion blower, 22 is a windproof member, 22 a is a recess, 22 b is a windbreak plate, and 22 C is a mounting leg. Note that the same reference numerals in the figures indicate the same parts.

Claims (1)

[Scope of utility model registration request] Combustion gas generated in the burner section passes through the interior of a device that has a combustion blower that forces air to the burner section and an indoor blower that sends air that has exchanged heat with the combustion heat generated in the burner section into the room. A heat exchanger is constituted by a plurality of pipes, and this heat exchanger is disposed in the air passage of the indoor blower, and a header is provided to collect the combustion gas in each of the pipes on the downstream side thereof, and A forced air heater characterized in that the header is provided with a windproof member that prevents the air flow from the indoor blower from directly hitting the header and has a lower thermal conductivity than the header.