JPS6034028B2 - 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, and aims to improve its heat exchange efficiency.

The general configuration of a forced air supply/exhaust type combustion machine is to introduce outdoor air, combust it, exchange heat with indoor air, and then exhaust the air outdoors again.

In recent years, there has been a trend towards increasingly higher thermal efficiency in response to market demands. When the temperature difference between the supply air temperature and the exhaust air temperature becomes 0, the efficiency becomes 100%, but in reality, 92 to 93% is considered to be almost the limit. One reason for this is that in order to increase thermal efficiency, the exhaust gas temperature must be lowered, and whether the fuel is liquid or gaseous, it has water vapor as a combustion product, and when the exhaust gas reaches the fog point, Water vapor condenses and corrodes the exhaust pipe, or depending on the temperature, it freezes inside the pipe, blocking the outflow of combustion air. Therefore, as a means to prevent this, it is necessary to maintain the exhaust gas temperature above a certain value, and this has been an impediment to improving thermal efficiency. The present invention eliminates the above-mentioned drawbacks, makes it possible to bring the thermal efficiency close to 100%, and furthermore prevents stripes of dew in the exhaust pipe or freezing thereof.

An embodiment will be explained below based on the drawings. The figure is a configuration diagram of an embodiment of the present invention. In the figure, 1 is a liquid combustion burner, such as a rotary atomizing type, which has a built-in blower for supplying and exhausting air.

2 is a combustion tube, and 3 is a heat exchanger consisting of a plurality of tubes, through which the combustion exhaust gas flows, and at the same time exchanges heat with indoor air by blowing air from a warm air blower (not shown). The exhaust gas is discharged as warm air to lower the temperature of the exhaust gas, and in conventional equipment, it is common to exhaust the exhaust gas outdoors through the windpipe 4 at this stage.

At this time, the exhaust gas temperature had to be kept above the dew point as described above. Reference numeral 5 denotes a secondary heat exchanger which is a subsequent stage of the heat exchanger 3, and the exhaust gas is first collected in an exhaust box 6 and then passed through a plurality of pipes constituting the secondary heat exchanger 5. It flows from the top to the bottom.

By forcibly blowing air to this secondary heat exchanger 5, the temperature of the exhaust gas that has passed through it becomes below the fog point, and the water vapor in the exhaust gas condenses into striped water, and the water conduit 7 equipped with a trap After that, it is stored in the drain tank 8. 9 is a pump that sends this condensed water to the humidifying tray 10; 11 is a switching valve;
The water supply channel is switched to an outdoor water discharge pipe 13 based on a signal from a water level detector 12 provided in the drain tank 8.

In this way, the two-stage heat exchangers 3 and 5 not only lower the exhaust temperature and perform a formal heat exchange with room temperature, but also
A portion of the latent heat is also obtained through the condensation of condensed water, so the same heating effect can be achieved even if the amount of combustion is reduced, leading to fuel savings.

On the other hand, the temperature of the exhaust gas is exchanged with the indoor air during deaeration, so if the outside air is below freezing, there will be cases where it will be further cooled in the exhaust pipe 4. The exhaust gas after mackerel dew water is condensed as the temperature decreases has reached saturated water vapor, and if the temperature decreases even slightly, it will immediately condense into mist. Therefore, in order to prevent this, the exhaust gas is passed through the exhaust box 6, which is in a relatively high temperature region, and is slightly heated. As a result, the exhaust gas has a margin with respect to the fog point, and it is possible to prevent silky fog in the middle of the exhaust pipe. And exhaust box 6
Since the high-temperature exhaust gas in the interior also loses heat through heat exchange with this low-temperature exhaust gas, the exchange load on the secondary heat exchanger 5 is reduced by that amount. It also becomes possible to make it relatively compact. As described above, the present invention cools exhaust gas to below the dew point through a heat exchanger, and uses the resulting condensation water for indoor humidification, etc., thereby transferring not only sensible heat but also a part of latent heat indoors. By heating the exhaust pipe again in the exhaust box to prevent fogging during the process of releasing the exhaust gas outdoors, it is possible to prevent condensation and freezing in the exhaust pipe, making it extremely practical. It becomes rich in sexuality. Furthermore, if the fuel contains water in the exhaust gas, it can be applied in a wide range of applications, as the same effect can be obtained with the same configuration whether it is a liquid or a gas. A simple explanatory diagram of the drawing is a configuration diagram of a hot air heater according to an embodiment of the present invention.

3... Heat exchanger, 5... Secondary heat exchanger, 6
...exhaust box.

Claims (1)

[Claims] 1 A hot air system in which combustion exhaust gas containing water vapor is cooled down to below the dew point using a heat exchanger, some of the condensed water is removed, and then passed through the high-temperature exhaust box again before being discharged outdoors. heater.