JPS63210561A - Hot air blower - Google Patents

Abstract

PURPOSE:To uniformly discharge a high-temperature hot air flow by providing independent convection fans at the upper parts or rear parts of the combustion side and exhaust cylinder side and operating both fans when the quantity of combustion is large and only the fan on the combustion part side when the quantity of combustion is small. CONSTITUTION:Two convection fans 8 are operated simultaneously by a control circuit when the quantity of combustion is large, and only the convection fan on the upstream side of the heat exchanger is operated when the quantity of combustion is small. Thus, air is sucked up from the rear surface and comes into contact with a heat exchanger 6 and is discharged through a hot water discharge port 11 in the form of a hot air flow of a high temperature. In a case where the output of a hot air blower is increased, the quantity of the fuel to be supplied through a fuel supply pipe 5 is increased and simultaneously the rotational speed of a fan 3 for combustion is increased to supply combustion air in a large quantity and to increase the quantity of combustion. However, since the quantity of an exhaust gas passing through the heat exchanger 6 increases in accordance with the increase in the quantity of combustion, the speed of the exhaust gas within the heat exchanger 6 becomes higher, and the heat exchange of the exhaust gas and the convection air is not carried out sufficiently only at the upstream side and the exhaust gas of a high temperature flows down to the downstream side and is heat-exchanged with the convection air at the downstream side, thus being cooled and discharged via an exhaust pipe 7 and a supply and exhaust gas top 1. On the other hand, the convection air is discharged through the hot air discharge port 11 in the form of a hot air flow of high temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a hot air fan for heating that uses combustion heat of gas, oil, etc.

2. Description of the Related Art Conventionally, as shown in FIG. 3, this heel hot air fan sucks air from an air supply/exhaust top 9 with a combustion fan 7, mixes it with fuel and burns it, and the combustion exhaust gas passes through a heat exchanger 12. and discharged from the air supply/exhaust top 9. On the other hand, convection air is generated by a convection fan 4, exchanges heat with a heat exchanger 12, becomes warm air, and is discharged from an outlet 2. To adjust the output of the hot air fan, adjust the rotation speed of the convection fan depending on the amount of combustion. For example, when reducing the output, reduce the amount of combustion and at the same time reduce the rotation speed of the convection fan to reduce the amount of convection air. Many methods are used.

Problems to be Solved by the Invention According to such conventional means, since the convection air touches the entire surface of the heat exchanger to exchange heat, when the output is reduced, the convection air also decreases along with the combustion amount. The cooling capacity of the part of the heat exchanger near the combustion section is reduced, leading to local overheating and damage to the heat exchanger when used for a long time.Furthermore, on the downstream side of the heat exchanger, the combustion exhaust gas flowing inside the heat exchanger Since the temperature of the heated air is lowered, the temperature of the heated air that has been heat exchanged is also lower, causing problems such as temperature unevenness in the heated air discharged from the outlet.

Means for Solving the Problems In order to solve these problems, the present invention provides independent convection fans on the upstream side (combustion section side) and downstream side (exhaust stack side) of the heat exchanger to reduce the amount of combustion. When the amount of combustion is large, both fans are operated, and when the amount of combustion is small, only the fan on the upstream side of the heat exchanger is operated.

Function In the above configuration, when the output is large, that is, when the amount of combustion is large, a large amount of high-temperature exhaust gas flows inside the heat exchanger, so almost the entire surface becomes high temperature, and the exhaust gas is sent from both the upstream and downstream convection fans. The air comes in contact with a high-temperature heat exchanger, undergoes heat exchange, and is discharged as warm air with a substantially uniform temperature on both the upstream and downstream sides. Next, when the output is low, the amount of high-temperature exhaust gas flowing inside the heat exchanger decreases, so the temperature on the upstream side becomes high, but the temperature on the downstream side decreases. Since the convection fan operates only on the upstream side, it cools only the high temperature section of the heat exchanger, and only the high temperature warm air is discharged from the heat exchanged air.

Example An embodiment of the present invention will be described below based on the drawings.

In FIGS. 1 and 2, reference numeral 1 denotes the supply/exhaust top, which is a double pipe in which combustion exhaust gas passes through the inside and air passes through the outside.

An air supply pipe 2 connects the outside of the air supply/exhaust top 1 and the suction side of the combustion fan 3. 3 is a combustion fan, 4 is a combustion section, and 5 is a fuel supply pipe for supplying fuel to the combustion section 4. A heat exchanger 6 is connected to the combustion section 4 on the upstream side and to the exhaust pipe 7 on the downstream side. 7 is an exhaust pipe that connects the heat exchanger and the inside of the air supply/exhaust top 1. A convection fan 8 is composed of a propeller fan and a motor, and one each is installed on the upstream and downstream sides of the heat exchanger. The convection fan may be a crossflow fan or a sirocco fan. A duct 9 forms a convection air flow path, and a partition plate 10 divides the convection air flow path in the duct 9 into an upstream side and a downstream side of the heat exchanger. Reference numeral 11 denotes a hot air outlet for discharging hot air.

In the above configuration, during operation of the hot air fan, combustion air is drawn in from the air supply/exhaust top 1 through the air supply pipe 2 by the combustion fan 3 and is supplied to the combustion section 4 . Fuel is supplied through a fuel supply pipe, mixed and combusted in the combustion section 4. After combustion, the high-temperature exhaust gas flows through the heat exchanger 6 from the upstream side (right side in Figure 1) to the downstream side (left side in Figure 1) while being cooled by convection air and passes through the exhaust pipe 7 to the supply/exhaust top. It is discharged from 1. On the other hand, the convection fans 8 are controlled by a control circuit (not shown) to operate two convection fans simultaneously when the amount of combustion is large, and when the amount of combustion is small, only the convection fan on the upstream side of the heat exchanger operates, drawing heat from the back side. exchanger 6
The hot air reaches a high temperature when it comes into contact with the air, becomes hot air, and is discharged from the hot air outlet 11.

When increasing the output of the hot air fan, the amount of fuel supplied from the fuel supply pipe 5 is increased and at the same time the rotational speed of the combustion fan 3 is increased to supply more air for combustion and increase the amount of combustion. As the amount of exhaust gas increases, the amount of exhaust gas passing through the heat exchanger 6 also increases, so the speed of the exhaust gas inside the heat exchanger 6 increases, and heat exchange between the exhaust gas and the convection air is sufficient only on the upstream side of the heat exchanger. The high-temperature exhaust gas that is not carried out flows to the downstream side and is cooled by heat exchange with the convective air on the downstream side.
, is discharged through the air supply and exhaust top 1. On the other hand, the convection air becomes high-temperature warm air and is discharged from the hot air outlet 11. Therefore, there is little difference in the temperature of the hot air between the heat exchanged on the upstream side of the heat exchanger 6 and the heat exchanged on the downstream side, and the hot air that comes out from the hot air outlet has a small temperature difference. .

When lowering the output of the hot air fan, the amount of combustion is reduced by reducing the amount of fuel and combustion air, but the speed of exhaust gas passing through the heat exchanger 6 is also reduced, so the heat on the upstream side of the heat exchanger is reduced. As the amount of exchange increases, the temperature of the exhaust gas decreases before it reaches the downstream. Therefore, when one convection fan is used as in the conventional example, the temperature of the hot air coming out of the hot air outlet becomes high on the upstream side of the heat exchanger and low on the downstream side of the heat exchanger, making it non-uniform.

One way to make the temperature of hot air uniform is to reduce the amount of convective air, but if you reduce the amount of convective air on the upstream side when the amount of combustion is low, the cooling capacity will decrease and the heat exchanger will locally overheat, resulting in a long It may be damaged after prolonged use. According to the configuration of the present invention, since only the fan on the upstream side with a large amount of heat exchange is operated, there is no generation of low temperature hot air, and it is possible to obtain hot air with a high temperature and uniform temperature whether the output is high or low. can.

Furthermore, since there is no need to reduce the amount of convective air on the upstream side of the heat exchanger when the amount of combustion is small, the heat exchanger is not overheated and damage can be reduced. Further, by providing the partition plate 10 in the duct 9 and separating the flow of convective air in the duct into the upstream side and the downstream side, the above-mentioned effects can be fully exhibited.

Effects of the Invention As is clear from the above explanation, the hot-air fan of the present invention has independent convection fans on the upstream and downstream sides of the heat exchanger, and when the amount of combustion is large, both fans are switched off when the amount of combustion is large. In some cases, by configuring only the fan on the upstream side to operate, (1) hot air with a high temperature and uniform temperature can be obtained regardless of the amount of combustion.

(2) The heat exchanger has little loss and has a long life.

The following effects can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a front view of main parts of a hot air fan according to an embodiment of the present invention;
The figure is a side view of the same, and FIG. 3 is a side view of the main part of the conventional example. 1... Supply and exhaust top, 3... Combustion fan, 4... Combustion section, 6... Heat exchanger, 8...
・Convection fan. Name of agent: Patent attorney Toshio Nakao and one other name
2 Figure 3

Claims (1)

[Claims] Independent convection fans are provided at the top and rear of the combustion section side and the exhaust stack side of the heat exchanger, and both fans are operated when the amount of combustion is large, and only the fan on the combustion section side is operated when the amount of combustion is small. Hot air machine.