JPS5939659B2 - Forced air supply/exhaust type hot air heater - Google Patents

Description

[Detailed description of the invention] The present invention relates to a forced air supply/exhaust type hot air heater.

In conventional forced air supply and exhaust hot air heaters, in addition to the standard installation where a supply and exhaust pipe is attached directly to the main body to supply and exhaust air to the outdoors, it is also possible to extend the exhaust pipe and air supply pipe by 2m to 3m and install a supply and exhaust pipe. , there was an extended installation to provide air supply and exhaust, but in either case, the heater body must operate normally, and when the exhaust pipe is extended to its maximum, the exhaust temperature will drop due to heat dissipation from the exhaust pipe. It is necessary to prevent the H2O content in the exhaust gas from condensing and draining.

Therefore, if the thermal efficiency is increased and the exhaust temperature at the outlet of the heater water body is lowered, condensate will occur in the exhaust pipe as described above, the ventilation resistance will change, and combustion will become unstable, resulting in the temperature of the exhaust gas at the outlet of the main body. There is a limit to the thermal efficiency, and it is not possible to achieve 100% thermal efficiency.

In general, the thermal efficiency of a forced air supply/exhaust hot air heater using petroleum fuel has a maximum of 92 to 93 coefficients when calculated based on the total calorific value, considering the generation of condensate.

At this time, the exhaust gas temperature differs depending on the excess air rate due to the amount of combustion air, but for example, if the excess air rate is 1.8,
The temperature is around 30°C to 140°C, and there should be no condensation of H2O in the exhaust, but in reality the ambient temperature of the extended exhaust pipe is low, at around 00°C to 20°C, so the temperature of the exhaust pipe itself is In some cases, the temperature is below 50℃, and the exhaust gas in contact with this temperature is close to that temperature and condensate is generated.
This condition can be said to be the limit under normal usage conditions.

That is, both by calculation and from the above, it can be seen that condensation of H, 0 minutes due to exhaust gas cooling occurs from about 50°C.

The present invention has been made with the above points in mind. During normal operation during extension installation, the exhaust pipe is heated with an electric heater so that the temperature at the supply and exhaust pipe at the end of the extension can be maintained at 50°C or higher, and the exhaust pipe is heated to 50°C or lower. By eliminating this part, no condensate is generated even if the exhaust temperature at the outlet of the main body is lowered to about 50°C, allowing normal operation, and the thermal efficiency can also be improved to about 98%. During standard installation, the thermal efficiency can be greatly improved to, for example, 98 degrees, compared to conventional products, even without the use of this electric heater-equipped exhaust pipe.

This will be explained below with reference to the drawings.

In FIG. 1, 1 is a forced air supply/exhaust hot air heater main body (hereinafter referred to as the main body), 2 is a wall that partitions the outdoors and indoors, and 3 is an air supply/exhaust terminal.

4 is an air supply pipe, and 5 is an exhaust pipe, which in this case is connected to the main body 1 and the supply/exhaust tube 3, respectively, during extended installation.

6 is a combustion fan, 7 is a burner, 8 is a heat exchanger, and 9 is a hot air fan.

The exhaust pipe 5 is connected to the exhaust pipe unit 5' as shown in FIG.
It is formed by being sealed and connected by a link 10,
An electric heater 11 is embedded in each.

The electric heater 11 is connected to each exhaust pipe unit 5', and only the portion connected to the supply and exhaust pipe 3 is short-circuited.

The other end of the electric heater 11 is electrically connected in parallel to a drive motor (not shown) of the combustion fan 6.

In the above configuration, the operation will be explained.

At the same time as the operation switch (not shown) of the main body 1 is turned on, fuel is supplied to the burner 7 and the combustion fan 6 rotates.

Air is therefore sent from the outdoors to the burner 7 through the air supply pipe.

When ignited at this point, the combustion gas flows from the heat exchanger 8 to the exhaust pipe 5.
The gas is guided through the air supply and exhaust pipe 3 and discharged outdoors.

The generated combustion heat is forcibly circulated through the indoor air by a hot air fan 9 in the heat exchanger 8, and the indoor air is received and heated.

Furthermore, the electric heater 11 is energized simultaneously with the rotation of the combustion fan 6, and the exhaust pipe 5 is maintained at a temperature of, for example, 508C or higher.

Thermal efficiency is good here, and the exhaust temperature at the outlet of the main body is 50%.
Even if the temperature is around °C, no condensate is generated because no heat is radiated when passing through the exhaust pipe.

As explained above, according to the present invention, no condensate is generated in the exhaust pipe during normal operation during extended installation, so the thermal efficiency of the main body during standard installation can be improved, which has the advantage of saving energy and reducing maintenance costs. .

[Brief explanation of drawings]

FIG. 1 is an explanatory cross-sectional view of an embodiment of the present invention, and FIG. 2 is a partially cross-sectional perspective view of an exhaust pipe according to an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Forced supply and exhaust hot air heater body, 3... Supply and exhaust pipe, 5... Exhaust pipe, 5'... Exhaust pipe unit, 6.
... Combustion fan, 11... Electric heater.

Claims (1)

[Claims] 1. An exhaust pipe unit having an electric heater attached to an extendable exhaust pipe of a forced air heater and a forced air heater, and having a circuit for energizing the electric heater during operation of the hot air heater,
A forced air supply/exhaust type hot air heater, characterized in that the hot air heater and an air supply/exhaust pipe attached to a wall are connected by the exhaust pipe unit.