JPS6140830A - Gas circulating furnace - Google Patents

Abstract

PURPOSE:To enable control of temp. of a gas circulating furnace at a set temp. quickly and accurately by providing a gas exhausting hole and a gas introducing hole for outside air to a gas circulating furnace, and providing also a valve being freely openable and closeable to the gas exhausting hole and the outside air introducing hole. CONSTITUTION:A glass vessel 4 to be heat-treated is placed on a table 5 in a heat-treating chamber 1 covered with a heat insulating material 2. Gas is introduced from a gas introducing port 8 and the gas exhausted from a gas exhausing port 9 is circulated to the gas introducing port 8 with a blower 13 through a gas circulating passage 10, 11. The gas is heated by a heating device 22 to execute heat treatment of the glass vessel 4. A gas exhausting hole 19 and an outside air introducing hole 20 are provided to the gas circulating furnace, and an openable/closeable valve 21 is provided to each hole 19, 20. By controlling the degree of opening of the valve 21, optimum amt. of hot gas in the gas circulating furnace is exchanged with optimum amt. of cold outside air. Thus accurate control of the furnace temp. to a set temp. is possible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a gas circulation furnace that can change the heating rate and cooling rate suitable for testing temperature.

[Conventional technology]

In order to reduce costs, glass molded products are cooled at a rate that does not leave thermal distortion in the molded product and in the shortest possible time. However, in order to test the cooling rate, a heat treatment chamber covered with a heat insulating material and in which the glass molded product is placed has a gas inlet on one side wall and a gas outlet on the other side wall. established,
A gas circulation furnace equipped with a circulation path for returning gas from the gas outlet to the gas inlet, a blower for circulating the gas in the circulation path, and a heating device for heating the gas,
By adjusting the heating device, the temperature was controlled according to various cooling programs. In this gas circulation furnace, when the cooling rate is slow, it is possible to obtain the cooling rate according to the cooling program by adjusting the heating device. However, if the cooling rate is fast, it cannot be cooled just by adjusting the heating device, and in this case, outside air is introduced into the heat treatment chamber for cooling, but a predetermined amount of outside air is introduced into the heat treatment chamber depending on the cooling rate. Since it is difficult to do so, excessive outside air is introduced and the operation of the heating device is adjusted to control the cooling rate to a predetermined rate. In such a gas circulation furnace, it is difficult to cool the furnace when the cooling rate is high, and it is necessary to supply energy such as electric power to the heating device even during cooling.

[Problem that the invention seeks to solve]

The object of the present invention is to provide a gas circulation furnace that allows easy cooling when the cooling rate is high and does not require supplying energy such as electric power to the heating device when the cooling rate is high.

[Means for solving problems]

The present invention provides a gas inlet on one side wall of a heat treatment chamber covered with a heat insulating material, a gas outlet on the other side wall, and a circulation path for returning gas from the gas outlet to the gas inlet. In a gas circulation furnace in which the circulation path is provided with a blower for circulating gas and a heating device for heating the gas, the gas circulation path is provided with a gas exhaust hole and an outside air introduction hole, and the gas exhaust hole is provided with a gas exhaust hole and an outside air introduction hole. and the outside air introduction hole are provided with a valve that can be opened and closed.In the present invention, the gas exhaust hole and the outside air introduction hole are connected to the heating device. is also provided adjacent to the circulation path on the gas discharge port side,
One butterfly valve that opens and closes simultaneously can be provided in the gas exhaust hole and the outside air introduction hole.

Further, in the present invention, a blower can be provided in the circulation path closer to the gas inlet than the heating device.

[For production]

The present invention provides a gas circulation furnace in which a gas circulation path is provided with a gas exhaust hole and an outside air introduction hole, a valve that can be opened and closed is provided in the gas exhaust hole and the outside air introduction hole, and the degree of opening of the valve is adjusted. A gas circulation furnace can exchange a desired amount of high-temperature gas with a desired amount of low-temperature outside air.

In addition, by providing one butterfly valve that opens and closes the gas exhaust hole and the outside air introduction hole at the same time, it is installed adjacent to the gas exhaust hole, the outside air introduction hole, and the circulation path on the gas exhaust port side of the heating device. By operating the valve, the high temperature gas inside the gas circulation furnace can be exchanged with the low temperature outside air. By providing the blower in the circulation path closer to the gas inlet than the heating device, the exchanged gas can be brought to a uniform temperature and then sent to the heat treatment chamber.

Example The embodiments shown in the drawings will be described in detail below.

11 is a gas circulation furnace, and a heat treatment section 1 is formed which is covered with heat insulating material λ on all four sides and on the top and bottom, and one peripheral surface is covered with heat insulating material 2.
A door 3 lined with a door 3 can be opened and closed by a hinge 31, and a glass container to be heat treated can be taken in and out of a mounting table j therein. In order to shorten the heating time and cooling time of this glass circulation furnace 1t, a ceramic fiber board is used for the inner wall 23 of the heat treatment chamber to reduce the heat capacity inside the furnace. This gas circulation furnace // consists of two opposing walls 6 and 7 of the heat treatment chamber/ that are perpendicular to the lining of the door 3 of the heat treatment chamber/, and U-shaped channel members arranged with a gap between them, and the gap is heat treated. 10. A gas circulation path with a gas discharge port located near the gas inlet of the chamber and returning gas from the gas discharge lower to the gas inlet. ll has been established. Gas circulation path I
A 7 am/3 for circulating the gas in the heat treatment chamber is provided in the gas circulation path below the inlet 12 of the continuous part between O and the gas circulation path. Attached to the other end of 4Z □Belt/I stretched between the pulled pulley/S and the pulley/J attached to the rotating shaft of motor/7
rotated through. The gas circulation path 10 is provided with a gas exhaust hole /9 and an outside air introduction hole 20 adjacent to each other, and one butterfly valve j/ that opens and closes at the same time. The butterfly valve 2/ is a swing frame lever 2 which is attached to the swing frame 26, the motor drive 2μ, and the butterfly valve 2, respectively, by an electric operation device j4'! ;, 27. This gas circulation furnace /l is provided with an electric device 22 that can control the amount of heat generated in the gas circulation path 10 between the position where the butterfly valve 2/ is provided and the intake port 12, and the gas circulation path 10 and /l The heating of the circulating gas is controlled according to a predetermined program.

That is, in this gas circulation furnace 1t, the input from the electric thermometer 29 provided in the heat treatment chamber 1 is controlled by the program controller 3.
0 and converted to DC current tt-2omA,
It is input to matching box 3/. The output from the matching device 31 is divided into a low side of 20 to 9 mA and a high side of 20 mA as shown in the figure. Low side 20-4mA output is adapter amplifier 2g
is amplified and input to electric actuator 2, gas exhaust port 1
9 and the outside air introduction hole 20 at the same time.
/ to operate.

On the other hand, the output of the high side G~-〇mA is output from the gate unit 32.
is input, the firing angle of the thyristor unit 330 is changed, and the electric heater 22 is controlled. In this case matching box 3/
Outputs 20mA on the low side when input is 4/mA,
The butterfly valve 21 is fully opened to introduce outside air, and the input l-m
At A, the output is 1iZmA, and the butterfly valve j/ is fully closed. During this time, the electric heater 22 is in an open state.

Input is /! When changing from mA to 20 mA, the electric heater 22 becomes the output state aK, and when the input is 2 (7 mA), the electric heater 22 becomes the maximum output state, and during this time the butterfly valve 21 remains fully closed.

〔Effect of the invention〕

As described above, in the gas circulation furnace according to the present invention, the gas circulation furnace is provided with the gas exhaust hole/9 and the air introduction hole 2o, and the gas exhaust hole/9 and the outside air introduction hole 2o are provided with valves that can be opened and closed. By adjusting the opening of the valve, the optimal amount of high-temperature gas in the gas circulation furnace can be exchanged with the optimal amount of low-temperature outside air, so the temperature can be quickly and accurately reached. It is possible to roll the electric heater 2-, and at the same time, it is not necessary to wastefully supply electric power to the electric heater 2-.

Further, in the gas circulation furnace according to the present invention, by providing the gas exhaust hole /q and the outside air introduction hole 20 adjacent to each other, the gas exhaust hole 19 and the outside air introduction hole 20 can be opened and closed simultaneously with one butterfly valve. It is easy to control the exact temperature.

[Brief explanation of the drawing]

1 to q show a gas circulation furnace according to the present invention,
Figure 1 is a vertically sectional front view, Figure 2 is a front view, Figure 3 is a partially vertical side view, Figure 5 is a cross-sectional plan view, Figure 5 is a control system diagram of the gas circulation furnace, Figure 6 is - indicating the input and output characteristics of the matching box. l: heat treatment chamber, l: gas inlet. ri: Gas exhaust port, 10. //: Circulation path. 13: Fan, /9 = Gas exhaust hole 10: Outside air introduction hole, 2/: Butterfly valve Fig. 1 q

Claims (2)

[Claims] (1) A gas inlet is provided on one side wall of a heat treatment chamber covered with a heat insulating material, a gas outlet is provided on the other side wall, and a circulation path is provided for returning gas from the gas outlet to the gas inlet, In a gas circulation furnace provided with a blower for circulating gas in the circulation path and a heating device for heating the gas, the gas circulation furnace is provided with a gas exhaust hole and an outside air introduction hole, and the gas exhaust hole and the outside air introduction hole are provided. A gas circulation furnace capable of adjusting temperature rise and fall, characterized in that a valve that can be opened and closed is provided in the outside air introduction hole. (2) The gas exhaust hole and the outside air introduction hole are provided adjacent to each other in the circulation furnace on the side of the gas exhaust port from the heating device, and one butterfly opens and closes the gas exhaust hole and the outside air introduction hole at the same time. A gas circulation furnace capable of controlling temperature rise and temperature fall according to claim 1, which is provided with a valve.