JPS59210234A - Hot air heater - Google Patents

Abstract

PURPOSE:To increase heat exchange efficiency and improve humidifying device by a method wherein water vapor in exhaust gas is condensed forcibly in a heat exchanger. CONSTITUTION:Air flow is blown against a multi-tube type secondary heat exchanger 4 equipped with radiating fins to reduce the temperature of exhaust gas forcibly and the temperature of the exhaust gas, passed therethrough, is reduced to a temperature lower than the dew point, then, the water vapor, as the products of combustion, is condensed and the condensed water is introduced into a drain tank 6. The secondary heat exchanger 4 is provided with a vertical type and discharging of the condensed water is facilitated by making the flow of the exhaust gas and the dropping direction of the condensed water the same direction. Water, reserved in the drain tank 6 is sent to a humidifying dish 9 by a pump 7 to utilize it for indoor humidifying. When the condensed water is reserved in the drain tank 6 so as to exceed the water sending capacity of the pump 7, a three-way switching valve 10 is switched by a water level detector 12 to communicate the pump 7 with a water discharging pipe 11 and discharge the condensed water to the outside of the room. In this case, the three-way switching valve 10 may be switched to the position of outdoor discharging by an operating signal.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a forced air supply/exhaust type warm air heater, and aims to improve its heat exchange efficiency and humidifier.

Conventionally, forced air supply and exhaust type oil hot air heaters generally have a configuration in which outdoor air is introduced, combusted, exchanged heat with indoor air, and then discharged outdoors again. According to this configuration, 90% The front and rear thermal efficiency is considered to be almost at its limit.

One of the reasons for this is that if we try to further increase thermal efficiency, the exhaust temperature will drop to around the dew point, and a large amount of water vapor contained in the exhaust gas will condense in the exhaust pipe, causing the pipe material to deteriorate. This is because the pipes may corrode or, depending on the temperature, may freeze inside the pipes, resulting in an obstruction to the inflow and discharge of combustion air.

The present invention solves the above-mentioned drawbacks, improves thermal efficiency and saves energy, and saves the effort of replenishing humidifying water by diverting dew condensation water to indoor humidification. below,
An example thereof will be described with reference to the drawings. In the figure, 1
For example, it is an oil-burning burner such as a rotary atomizing type, and has a built-in blower for air supply and exhaust. 2 is a combustion tube, and 3 is a heat exchanger consisting of multiple pipes.In conventional equipment, exhaust gas was vented outdoors at this stage. There are various configuration methods for the heat exchanger 3. For example, when adopting the multi-tube configuration as described above, air is forced between the tubes (the blower is not shown). 1) It exchanges heat with indoor air to lower the exhaust temperature and at the same time sends warm air into the room.

In conventional equipment, the temperature of the exhaust gas that has passed through the heat exchanger 3 is usually above the dew point and does not form condensation.
If the outside temperature was extremely low or if the exhaust pipe was longer than necessary, there was a possibility of condensation inside the pipe.

Reference numeral 4 denotes a multi-tubular secondary heat exchanger equipped with radiation fins, etc., which is placed downstream of the heat exchanger 3, and wind is applied to this as well to forcibly lower the exhaust temperature. By appropriately selecting the relationship between the configuration of the secondary heat exchanger 4 and the amount of forced air for cooling,
The temperature of the exhaust gas passing through this can be lowered to below the dew point. Therefore, water vapor as a combustion product condenses,
The condensed water is led to the drain tank 6 through a water pipe 6 provided with a trap. Since dew condensation gradually progresses in the secondary heat exchanger 4, the secondary heat exchanger 4 is placed vertically so that the condensed water does not accumulate in the narrow tubes and obstruct the passage of exhaust gas. It is configured so that dew condensation water easily flows downward and exhaust gas flows downward from above. In particular, by making the flow of the exhaust gas and the falling direction of the condensed water in the same direction, the rapid discharge of the condensed water to the outside of the tube is facilitated.

The water accumulated in the drain tank is transferred to the water pipe 8 by the pump 7.
The water is sent to the humidifying tray 9 through the humidifying tray 9, and by a portion of the combustion heat given to the humidifying tray 9, it becomes water vapor again and is used for indoor humidification.

A three-way switching valve 1o is installed in the middle of this water pipe 8, and a drain pipe 11 is installed to discharge water outdoors.
are connected. Normally, three-way switching valve 1° is pump 7
When the condensed water exceeds the water supply capacity of the pump 7 and accumulates in the drain tank 6, the three-way switching valve 10 is activated by the water level or water amount detector 12. The pump 7 and the drain pipe 11 are switched to communicate with each other, and the condensed water is discharged outdoors.

Moreover, when the user wants to stop humidification, the three-way switching valve 1o can be switched by an operation signal. The operation signal is obtained by a switch 13 on the operation panel on the front of the hot air fan. A part of the control circuit for this purpose is shown in FIG. Second
In the figure, 14 indicates a relay, and 16 indicates its contact.

Normally, the humidifying capacity of a humidifying device using combustion heat depends on how it is configured, but it only uses 6 to 1% of the combustion calorific value, which accounts for less than the total water vapor in the kerosene combustion exhaust gas. ~It's almost false. Therefore, as the heat exchange efficiency increases, the amount of condensed water always exceeds the amount consumed by humidification, and a control method that stops the operation of the equipment based on the signal from the water level detector 12 becomes possible. It is predicted that the frequency of equipment outages will be quite high, which is not desirable considering its original function as a heater.

On the other hand, the necessity of humidification is determined by the user's living environment or subjective judgment rather than by the equipment, and there are quite a few occasions when it is desired to stop humidification, and in this case, drain accumulates even more quickly. Therefore, in order to cope with these problems, it is extremely effective to have a device that automatically drains water outdoors.

As described above, the present invention forcibly condenses the water vapor in the exhaust gas in the heat exchanger, thereby lowering the exhaust temperature to the same level as the supply air temperature, and extremely reducing the amount of heat released outdoors.

Furthermore, by causing dew condensation, in addition to the sensible heat exchange described above, a portion of the latent heat is also released indoors, resulting in an extremely high overall energy saving degree. Furthermore, since condensed water is used for humidification, there is no need to replenish humidifying water, making it more convenient than conventional devices that use tap water. Furthermore, humidification can be stopped using a switching valve, and condensed water can be automatically discharged outdoors without stopping the operation of the equipment.

In the above embodiments, the case of an oil combustor has been described, but the same effect can be obtained even in the case of a gas combustor containing water in the exhaust gas, such as a gas combustor, and the range of application is wide.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a hot air heater according to an embodiment of the present invention, and FIG. 2 is a control circuit diagram thereof. 3...Heat exchanger, 4...Secondary heat exchanger, 6...Drain tank, 7...Bo/P, 8...・・Water pipe, 9 ・・humidifying tray, 10
...Three-way switching valve, 11...Drain pipe. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
figure

Claims (1)

[Scope of Claims] (1) A heat exchanger that cools combustion exhaust gas containing water vapor to below the dew point, a drain tank that stores dew condensed water condensed by this heat exchanger, and a pump that sends this condensed water to a humidifying tray. A water supply means having a water supply pipe, and a water supply means provided in the middle of the water supply pipe,
It consists of a switching valve that connects the pump and the humidifying dish in one direction, and the pump and the outdoor water discharge pipe in the other direction, and a water level detector installed in the drain tank. A warm air heater configured to switch the three-way switching valve in response to any of the stop operation signals and discharge condensed water outdoors through a drain pipe. ≧) Consisting of two stages of heat exchangers, front and rear, the exhaust gas is cooled to below the dew point in the latter stage heat exchanger, and the latter stage heat exchanger is of a vertical type according to claim 1. hot air heater. (3) The hot air heater according to claim 2, wherein the heat exchanger in the latter stage is configured so that the exhaust gas flows from above to below.