JPH0215490B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a gas circulation furnace capable of adjusting temperature rise and fall;
In particular, the present invention relates to a gas circulation furnace that can change the heating rate and cooling rate suitable for testing a cooling rate that does not leave thermal strain on glass molded products.

[Conventional technology]

In order to reduce costs, glass molded products are required to be cooled at a rate that does not leave thermal distortion in the molded product and in the shortest possible time. , and a heat treatment chamber 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, and a circulation path for returning gas from the gas outlet to the gas inlet; A gas circulation furnace is equipped with a blower for circulating gas in the circulation path and a heating device for heating the gas, and the temperature can be controlled according to various cooling programs by adjusting the heating device. Ta. In this gas circulation furnace, when the cooling rate is slow, the cooling rate can be obtained in accordance with the cooling program by adjusting the heating device. However, if the cooling rate is fast, cooling cannot be achieved simply by adjusting the heating device.
In this case, outside air is introduced into the heat treatment chamber for cooling, but it is difficult to introduce a predetermined amount of outside air into the heat treatment chamber depending on the cooling rate, so an excessive amount of outside air is introduced to operate the heating device. The cooling rate is adjusted and controlled to a predetermined cooling rate. In such a gas circulation furnace, cooling is difficult when the cooling rate is fast, 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. This is 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 and the outside air introduction hole.

In the present invention, the gas exhaust hole and the outside air introduction hole are provided adjacent to the circulation path on the side of the gas exhaust port from the heating device, and one butterfly that simultaneously opens and closes the gas exhaust hole and the outside air introduction hole. A valve may be provided.

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

[Effect]

The present invention provides a gas circulation furnace in which a gas exhaust hole and an outside air introduction hole are provided in the gas circulation path, 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 desired amount of hot gas in the gas circulation furnace can be exchanged with a desired amount of cold outside air.

In addition, by installing 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. The operation allows the exchange of high-temperature gas in the gas circulation furnace with 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.

Examples Examples shown in the drawings will be described in detail below.
Reference numeral 1' denotes a gas circulation furnace, in which a heat treatment 1 is formed which is covered with heat insulating material 2 on all four sides and on the top and bottom, and one of the peripheral surfaces of the heat treatment furnace 1 is lined with heat insulating material 2 and can be opened and closed by a door 3 with a hinge 3'. A glass container 4 to be heat treated can be put in and taken out from a mounting table 5 therein. In order to shorten heating time and cooling time, this glass circulation furnace 1' uses ceramic fiberboard for the inner wall 23 of the heat treatment chamber to reduce the heat capacity inside the furnace. This gas circulation furnace 1' is constructed by arranging U-shaped channel members with a gap between two opposing walls 6 and 7 of the heat treatment chamber 1, which are perpendicular to the lining of the door 3 of the heat treatment chamber 1, and heat-treating the gaps. A gas inlet 8 and a gas outlet 9 of the chamber are provided, and gas circulation paths 10 and 11 for returning gas from the gas outlet 9 to the gas inlet 8 are provided. A fan 13 for circulating the gas in the heat treatment chamber 1 is provided in the gas circulation path 11 below the intake port 12 in the continuous portion between the gas circulation path 10 and the gas circulation path 11.
Pulley 15 and motor 1 attached to the other end
It is rotated via a belt 18 stretched between a pulley 16 attached to a rotating shaft of No. 7. The gas circulation path 10 has a gas exhaust hole 19 and an outside air introduction hole 20.
A single butterfly valve 21 is provided which is adjacent to and opens and closes at the same time. This butterfly valve 21 is operated by a swinging rod 26 by an electric actuator 24.
It is opened and closed by the electric actuator 24 and swing rod levers 25 and 27 attached to the butterfly valve 21, respectively. This gas circulation furnace 1' includes 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 21 is provided and the intake port 12.
is provided, and the gas circulating through the gas circulation paths 10 and 11 is heated and controlled according to a predetermined program.

That is, in this circulation furnace 1', an input from an electric thermometer 29 provided in the heat treatment chamber 1 is input to a program controller 30, converted to a DC current of 4 to 20 mA, and input to a matching box 31. The output from the matching box 31 is 20 to 4 mA on the low side and 4 mA on the high side as shown in Figure 6.
Divided into ~20mA. The low side 20 to 4 mA output is amplified by the adapter amplifier 28 and sent to the electric actuator 24.
is input, and the butterfly valve 21 that opens and closes the gas exhaust hole 19 and the outside air introduction hole 20 at the same time is operated.

On the other hand, the high side output of 4 to 20 mA is input to the gate unit 32, and the thyristor unit 33
The electric heater 22 is controlled by changing the firing angle of the electric heater 22 .
In this case, the output from the matching box 31 is 20 mA on the low side when the input is 4 mA, the butterfly valve 21 is fully opened to introduce outside air, and the output is 4 mA when the input is 12 mA, and the butterfly valve 21 is fully closed. During this time, the electric heater 22 is in an open state. Input from 12mA
When the input is 20 mA, the electric heater 22 becomes the output state, and when the input is 20 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 19 and the air introduction hole 20, and the gas exhaust hole 19 and the outside air introduction hole 20 are provided with valves that can be opened and closed. By adjusting the opening degree of the valve, the optimum amount of high temperature gas in the gas circulation furnace can be exchanged with the optimum amount of low temperature outside air, so the set temperature can be controlled quickly and accurately. At the same time, it is possible to avoid unnecessary power supply to the electric heater 22.

Further, the gas circulation furnace according to the present invention has a gas exhaust hole 1
By providing the gas exhaust hole 19 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, making it easier to accurately control the temperature.

[Brief explanation of drawings]

1 to 4 show a gas circulation furnace according to the present invention, in which FIG. 1 is a longitudinally sectional front view, FIG. 2 is a front view thereof, FIG. 3 is a partially longitudinally sectional side view, and FIG. 4 is a longitudinally sectional front view thereof. A cross-sectional plan view, FIG. 5 is a control system diagram of the gas circulation furnace, and FIG. 6 is a diagram showing the input and output characteristics of the matching box. 1: Heat treatment chamber, 8: Gas inlet, 9: Gas outlet, 10, 11: Circulation path, 13: Fan, 19:
Gas exhaust hole, 20: Outside air introduction hole, 21: Butterfly valve.

Claims (1)

[Scope of Claims] 1 A circulation system in which a gas inlet is provided on one side wall of a heat treatment chamber covered with a heat insulating material and a gas outlet is provided on the other side wall, and the gas from the gas outlet is returned to the gas inlet. In a gas circulation furnace, the gas circulation furnace is provided with a gas exhaust hole and an outside air introduction hole, and is provided with a blower for circulating gas in the circulation path and a heating device for heating the gas. A gas circulation furnace capable of adjusting temperature rise and fall, characterized in that a gas exhaust hole and an outside air introduction hole are provided with valves that can be opened and closed. 2. Providing the gas exhaust hole and the outside air introduction hole adjacent to each other in the circulation furnace on the side of the gas exhaust port from the heating device,
Claim 1, which is provided with one butterfly valve that simultaneously opens and closes the gas exhaust hole and the outside air introduction hole.
A gas circulation furnace capable of adjusting temperature rise and temperature fall as described in Section 1.