JPS6333069B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hot air supply device for supplying high-temperature gas for maintaining the temperature inside the drying furnace, which has a tunnel-like shape between an inlet and an outlet.

In this type of hot air supply device for a drying oven, since the material to be dried at a low temperature is supplied to the inlet side zone of the drying oven, the heat load is greater than that in zones other than this inlet side zone. Therefore, the inlet side zone and other zones had different heat loads.

For this reason, conventionally, when supplying high-temperature gas to a drying furnace, a gas heating device is used to control the heating temperature in order to maintain a constant temperature inside the furnace in the inlet side zone, and a separate gas heating device is used to supply high temperature gas to the drying furnace. A gas heating device was provided whose heating temperature was controlled to maintain a constant furnace temperature in the zone.

In other words, in the past, multiple gas heating devices were installed, which required multiple structures for heating temperature control, resulting in poor productivity and low individual heating capacity, resulting in overall energy loss. It had a big drawback.

In supplying hot air to multiple locations, the present invention does not use gas heating devices equal to the number of supply locations or the types of temperature settings at each location, but uses a smaller number of gas heating devices. It is an object of the present invention to supply hot air so that the temperature at a plurality of locations is maintained according to a set temperature.

The characteristic configuration of the present invention for achieving this purpose is that, in a drying oven having a tunnel-like structure between an inlet and an outlet, an inlet-side zone of the oven is placed near the inlet of the drying oven. A first supply path for supplying high-temperature gas for temperature maintenance and a second supply path for supplying the high-temperature gas to a zone in the furnace closer to the outlet side than the inlet side zone, and Connect the exhaust air duct of the to the inlet duct of the gas heating device,
A branch point between the first supply path and the second supply path is connected to the outlet duct of the gas heating device to form a circulation path for the supplied high temperature gas, and a flow path is further connected to the outlet duct of the gas heating device. A low-temperature gas intake passage that mixes gas at a lower temperature than the high-temperature gas that has passed through the gas heating device is connected to the second supply passage on the downstream side, and the air volume of the inflowing gas from the low-temperature gas intake passage is adjusted. The structure is equipped with an air volume adjustment mechanism.

By configuring it in this way, only one set of structure is needed for heating temperature control, which improves productivity, and also makes it possible to reduce the heating capacity of the heating device for the required heating amount of high-temperature gas compared to conventional systems. .

An example in which the present invention is applied to a hot air drying oven for baking paint on automobile bodies will be explained with reference to FIGS. 1 and 2.

Reference numeral 1 denotes a furnace body of a hot air drying oven, which is formed into a tunnel shape with an opening closed by an air curtain at an inlet part 2 and an outlet part 3, and a heating part 4 between the openings and a coating booth 5. are connected by a setting zone 6.

Side walls 9 and ceiling 1 excluding openings at both ends of the furnace body 1
0 and floor 11 are double walls filled with heat insulating material.

Air ducts 13 and 15 are provided on the inner surfaces of the side walls 9 and 9 of the furnace body 1, respectively, for circulating hot air into the furnace space 12.
and return air ducts 14, 16 are provided. These blower ducts and return air ducts are a first blower duct 13 and a first return air duct 14 on the inlet side from the center of the furnace body 1, and a second blower duct 15 and a second return air duct 16 on the outlet side from the center. It is divided into. In this way, in the hot air circulation system in the furnace, the heating section 4 is divided into the first heating section 7, which is the inlet side zone, and the second heating section 8, which is the outlet side zone.

A blower outlet 17 is provided on the side of the furnace space 12 of the blower ducts 13 and 15, and a blower outlet 17 is provided on the side of the furnace space 12 of the blower ducts 13 and 15.
A suction port 18 is attached to the inside 12 side of the furnace.

In addition, in the furnace space 12, there are carts, rails, and a conveyor chain (not shown) for transporting an automobile body 19, which is an example of a painted object to be dried.
A transport device such as the following is provided.

Outside the furnace body 1, there are first
First ventilation chamber 2 connecting the ventilation duct 13
0, the second ventilation chamber 22 connecting the left and right second ventilation ducts 15 of the second heating section 8, the first heating section 7
a first return air chamber 21 that connects the left and right first return air ducts 14, and a second return air chamber 23 that connects the second return air duct 16 of the second heating section 8;
Both are installed at the top of the ceiling.
(See Figure 1) (In Figure 2, these air ducts 13, 15,
Return air ducts 14 and 16 are not shown and are omitted) Next, each of the chambers 20, 21, 22, 23
The connection relationship between the heater 27 and the gas burner heater 27 will be explained with reference to FIG.

The first return air chamber 21 and the second return air chamber 23 are connected to the inlet duct 26 of the heater 27 via intermediate ducts 24 and 25, respectively, which serve as exhaust air paths from inside the furnace.

The outlet duct 31 of the heater 27 is
It is connected to both the ventilation chambers 20 and 22 via first and second distribution ducts 29 and 30 that constitute two divided first and second supply paths. 32
are blowers provided in each of the distribution ducts 29 and 30.

In this way, a first supply path for supplying hot air, which is a drying-like heating fluid, from the heater 27 to the first heating section 7 corresponding to the inlet side zone of the drying furnace, and a drying flow from the heater 27 are provided. A second supply path is provided for supplying hot air, which is a heating fluid, to the second heating section 8, which is a zone closer to the outlet section 3 than the inlet side zone.

The heating temperature by the heater 27 is controlled by adjusting the amount of gas supplied by a control valve 28 provided in a gas supply path to the gas burner (not shown).

A temperature detector 35 is attached to the intermediate duct 24 connected to the first return air chamber 21 of the first heating section 7 to detect the air temperature inside the intermediate duct 24 .

In response to the temperature signal detected by the temperature detector 35, the heating temperature is used to operate the control valve 28 in order to adjust the heating temperature of the heater 27 so that the air temperature in the intermediate duct 24 is at a constant temperature. A regulator 36 is provided.

The gas heating device A is composed of the heater 27, the control valve 28, the heating temperature regulator 36, and the temperature detector 35.

A bypass duct 33 branched from the inlet duct 26 of the heater 27 is connected to the upstream side of the blower 32 of the second distribution duct 30 on the second heating section 8 side. A damper is provided as an air volume adjustment mechanism to adjust the amount of inflow of low temperature gas.

A temperature detector 37 is attached to the intermediate duct 25 connected to the second return air chamber 23 to detect the internal air temperature. In response to the temperature detection signal from the temperature detector 37, the opening degree of the air volume adjustment damper 34 is adjusted so that the air temperature in the second distribution duct 30 becomes a set value. A temperature regulator 38 is provided which regulates the exhaust air supply via the bypass duct 33 to the distribution duct 30.

In this way, the bypass duct 33, the damper 34, the temperature regulator 38, and the temperature detector 37 are used to control the temperature of the second distribution duct 30 to be lower than the temperature of the first distribution duct 29. A lowering device B is configured.

39 is a second distribution duct 30 for fixedly adjusting the air volume division ratio to the distribution ducts 29 and 30.
This is a damper installed in the

Next, the state of use of the above configuration will be explained.

Hot air (approximately 150°C) in the furnace of the first heating section 7
is sucked into the left and right first ducts 14 in the furnace from the suction port 18, and then into the first return air chamber 21 and the intermediate duct 2.
4. The hot air is heated by the heater 27 through the inlet duct 26, and is controlled to an appropriate temperature of about 180°C to 200°C, and then flows into the outlet duct 31, the second distribution duct 29,
It enters the first air duct 13 on the left and right sides of the furnace through the blower 32 and the first air chamber 20, and its air outlet 1
From 7, it is supplied into the furnace 12 and circulated.

The in-furnace hot air temperature of the second heating section 8 is approximately 150° C., which is approximately equal to the in-furnace hot air temperature of the first heating section 7.
The air passes through and reaches the inlet duct 26, where it mixes with the return air hot air from the first heating section 7 and is heated by the heater 27 as described above to become hot air heated to a temperature of 180 to 200°C. It passes through the duct 31 and exits to the second distribution duct 30.

Here, a bypass duct 33 branched from the inlet duct 26 is connected to the temperature lowering device B.
The air temperature in the second distribution duct 30 is lowered to a temperature of 150°C to 200°C which is suitable for maintaining the temperature of the second heating section 8 (150°C) by sending an appropriate amount of hot air at about 150°C through the , the blower 32 passes through the second blow chamber 22 and from the second blow duct 15 to the second blow chamber 22.
It is supplied to the heating section 8.

The heating temperature by the heater 27 is controlled by the temperature detector 35, the temperature regulator 36, and the gas regulating valve 28 by the temperature of the hot air in the intermediate duct 24.
The temperature of the hot air in the intermediate duct 24 is approximately equal to the average temperature in the furnace of the first heating section 7, and the heating device A is
The temperature in the furnace of the first heating section 7 substantially increases the temperature of the heater 2.
The amount of heating in step 7 will be controlled.

On the other hand, the amount of hot air passing through the bypass duct 33 is controlled by the hot air temperature in the intermediate duct 25 through a temperature detector 38 and a regulating damper 34.
The temperature of the hot air in the intermediate duct 25 is approximately equal to the average temperature in the furnace of the second heating section 8, and the amount of air blown through the bypass duct 33 is substantially controlled by the temperature in the furnace of the second heating section 8. become.

In this way, the temperature of the air blown to the first heating section 7 and the second heating section 8 is determined by the in-furnace load heat amount of both heating sections 7 and 8, and the in-furnace load amount of each is determined by the amount of heat applied to the heated object. It varies depending on the amount of passage of the automobile body 19.

Generally, the temperature of the hot air inside the drying oven must be raised to a predetermined temperature (150°C in this case) before the start of painting work. Since the heat does not pass through the furnace, the heating load heat amount of the first heating section 7 and the second heating section 8 is approximately equal, and the temperature of air blown to both heating sections 7 and 8 may be approximately equal. Therefore, at this time, the adjustment damper 34 is closed so that the amount of air blown through the bypass duct 33 is approximately zero.

When the painting work is started and the objects to be heated, such as automobile bodies, trolleys, and conveyor chains, begin to pass through the drying oven, the heating load heat amount of the first heating section 7 increases, and therefore air is blown to the first heating section 7. Since the temperature of the hot air is required to be higher than the temperature of the air blown to the second heating section 8, in order to lower the temperature of the hot air blown to the second heating section 8 to the required temperature,
The adjustment damper 34 is opened to an appropriate degree to adjust the amount of hot air at 150° C. passing through the bypass duct 33.

In this way, this device can always control the furnace temperatures of the first heating section 7 and the second heating section 8 to a predetermined temperature.

The configuration of the above embodiment may be modified by one or more of the following combinations.

Not only when the set furnace temperatures of both heating sections 7 and 8 are approximately the same (150°C), but also when the respective furnace temperatures (set temperatures) are different, the control capability range of the heater 27 and temperature lowering device B It can be applied within.

The drying oven should be a tunnel-type drying oven used not only for painting but also for other purposes.

Furthermore, the objects to be dried are not limited to automobile bodies, but also various painted or unpainted objects, water-containing cakes (sludge), etc.

The heating section 4 is not limited to two, but should be divided into three or more.

At this time, the intermediate duct 25, the second distribution duct 3
A plurality of temperature reducing devices B may be provided corresponding to those in the inlet side zone. The plurality of distribution ducts are collectively referred to as a second supply path in the claims.

In addition, the length of each zone is not limited to equal divisions; if the entrance zone is shorter or longer than other zones, or if it is divided into three or more zones, the entrance zone and exit zone are Make the middle zone longer or shorter than the side zones.

The temperature lowering device B has a structure in which an outside air intake duct is provided as a low temperature gas intake path in place of the bypass duct 33, and a damper provided in this duct is adjusted.

At this time, the inlet duct 26 may be provided with an outlet for discharging to the outside an amount of hot air that matches the intake amount of outside air.

Further, the temperature lowering device B has a structure in which a damper for the outside air intake duct shown in 1 and a damper for the bypass duct are installed together, and both dampers are used in parallel.

The temperature detectors 35, 36 are attached to both the return air ducts 14, 16, and
The structure shall be configured to measure the air temperature within 16.

In the above, the return air ducts 14, 16 are connected to one return air chamber, and the inlet duct 26 is directly connected to this chamber.

A blower 32 is provided in each intermediate duct 24, 25.

The heater 27 should be of an electric heating type.

In this case, the heating temperature should be adjusted using a regulator that controls the amount of electricity supplied to the electric heater by controlling the voltage or current.

Various known specific structures are used for the regulator.

The return air ducts 14 and 16 and the blower ducts 13 and 15 are provided on the ceiling 10 and the floor 11.

One of the return air ducts 14, 16 and the blower ducts 13, 15 is provided on the ceiling 10, and the other is provided on the floor 11.

In this case, the return air ducts 14 and 16 are
If the ventilation ducts 13 and 15 are provided on the floor 11, return air in the furnace can be easily distributed evenly by natural convection.

The chamber may be provided not only on the ceiling 10 of the furnace body 1 but also on the outside of the side walls 9, 9 and/or the floor 11.

The furnace body 1 is not limited to a straight one, but may be curved or meandering in plan view, inclined in the vertical direction, or vertical.

In short, any long cylindrical shape whose four circumferential parts are substantially separated from the outside by walls is sufficient.

Further, the cross-sectional shape of the furnace body 1 is not limited to a square, but may be various shapes such as a circle, an ellipse, and a horse-shaped shape.

The above is collectively referred to as a tunnel shape in the claims.

[Brief explanation of the drawing]

The drawings show an embodiment of the hot air supply device for a drying oven according to the present invention, and FIG. 1 is a partially cutaway perspective view showing a part of the drying oven, and FIG. 2 is a flowchart. 2... Inlet part, 2... Outlet part, 1... Furnace body, 7
...First heating part (inlet side zone), 8...Second heating part, 24, 25...Exhaust air path, 26...Inlet duct, 29...First supply path, 30...Second supply path , 31... Outlet duct, 33... Low temperature gas intake path, 34... Air volume adjustment mechanism, A... Gas heating device, B... Temperature lowering device.

Claims (1)

[Claims] 1 A first supply for supplying high-temperature gas for maintaining the temperature inside the furnace to the inlet side zone of the furnace near the inlet part 2 to the drying furnace formed in a tunnel shape between the inlet part 2 and the outlet part 3. The passage 29 is connected to a second supply passage 30 that supplies the high-temperature gas to a zone in the furnace closer to the outlet 3 side than the inlet side zone, and the exhaust air passages 24 and 25 from inside the furnace are connected to It is connected to the inlet duct 26 of the heating device A, and the branch point of the first supply path 29 and the second supply path 30 is connected to the outlet duct 31 of the gas heating device A to circulate the supplied high temperature gas. A low-temperature gas intake path 33 that forms a flow path and further mixes gas at a lower temperature than the high-temperature gas that has passed through the gas heating device A into the second supply path 30 on the downstream side of the flow path from the branch point. A hot air supply device for a drying oven, which is connected to a hot air supply device for a drying furnace and is equipped with an air volume adjustment mechanism 34 that adjusts the air volume of the inflowing gas from the low temperature gas intake path 33.