JPS5850236Y2 - Heating furnace with cooling tube - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a heating furnace with a cooling tube for testing and testing specimens that repeat heating and cooling.

Conventionally, heating furnaces that repeatedly heat and cool a specimen to test changes in its structure and strength, have been used to simulate natural cooling, and those that use a cooling medium in the furnace. An improved version has been used that performs forced cooling by introducing and discharging the air inside the tank.

Figure 1 shows a welded part 01 of a steel pipe 01 as an example of the latter category.
This shows a heating furnace 02 in which the strength of A is tested by repeatedly heating and cooling it.A pull rod 0 supports a steel pipe 01 as a specimen in the furnace and applies a tensile load to it.
3A and 03B pass through both ends of the furnace, an electric heating coil 04 is provided along the side wall inside the furnace, and an air pressure feeding pipe 06 equipped with a solenoid valve 05 as a forced cooling means is communicated with the inside of the furnace. An in-furnace ventilation outlet 07 and a butterfly-shaped lid 08 that opens with air pressure are provided therein.

The heating furnace 02 with the above configuration is used to perform a temperature cycle of the test specimen heating and cooling test as shown in Fig. 2. During heating, the furnace walls and wide furnace are cooled to approximately the lower limit temperature in the cooling process of the preceding cycle. Since it is not possible to raise the temperature of specimen 01 to the predetermined upper limit temperature without consuming a large amount of heat to heat the internal gas, heating requires a lot of time and heat, while forced cooling requires a large amount of heat. In order to lower the temperature of specimen 01 to a predetermined lower limit temperature, it also required a lot of time and operation of the forced cooling means to cool the furnace wall and the entire gas inside the furnace.

However, since this test temperature cycle requires over 8000 cycles to test one specimen (or multiple rod specimens conducted simultaneously in the same furnace), it is necessary to shorten heating and cooling times and to There has been a strong demand for the accompanying reduction in power consumption.

The present invention was made in order to solve the above-mentioned demands for the conventional ones, and it provides a cooling cylinder that surrounds the specimen in the furnace and, if necessary, its support mechanism, to partition the air space inside the furnace, and also to provide forced cooling. By applying the method only to this section of the cooling cylinder, it is possible to reduce the air space that must be directly cooled when cooling the specimen, and to slow the cooling down to the furnace wall by making the cooling indirect. At the start of the heating process, it is possible to use the furnace walls, which are hotter than conventional ones, and a part (actually, the majority) of the air space, which is also high in temperature, thereby creating a heating furnace with high work efficiency and high thermal efficiency. It provides:

Hereinafter, the present invention will be specifically explained based on embodiments shown in the drawings.

The first embodiment of the present invention shown in FIGS. 3 and 4 is a heating furnace in which a steel pipe having a welded portion 1A as a specimen 1 is subjected to repeated heating and cooling operations to test its strength. The furnace body 2, which is vertically divided into two parts, is configured to be openable and closable by a hinge 3.

Pull rods 5A and 5B as support mechanisms are attached to both ends 4A of the furnace body 2 so as to support the specimen 1 brought into the furnace.
, 4B to be attached to both ends of the specimen by slidingly penetrating through 1. Further, the pull rod 5 is pulled by a device not shown in the drawings so as to apply a tensile stress to the specimen 1.

A nichrome wire 7 as a heating means is provided along the inner surface of the side wall 6 of the furnace, and the nichrome wire 7 is connected to a heating control device (not shown) that operates in response to a signal from a temperature measuring element (not shown) attached to the specimen 1. It is connected to a power supply (not shown) through the power supply.

Furthermore, a cooling cylinder 8 divided into two is provided inside the furnace, surrounding the specimen 1 and the pull rod 5, and dividing the air space inside the furnace into an air space inside and outside the cooling cylinder.

The cooling cylinder 8 is vertically divided into two parts, and each divided cooling cylinder is attached at both ends to the corresponding divided furnace body, and opens and closes as the furnace body 2 opens and closes in a double-door manner.

Further, at both ends 4A and 4B of the furnace body, a cooling medium introduction hole 9° and a cooling medium discharge hole 12, which open into the inner air space of the cooling cylinder 8 in the furnace, are provided, respectively, and the cooling medium is introduced from a cooling medium blower (not shown). The pipe 10 is removably inserted into the introduction hole 9 via a solenoid valve 11 that opens and closes in response to a signal from a heating control device.

(See Figures 1 and 2) The number of discharge holes 12 is equal to the number of introduction holes 9. A butterfly-shaped lid 13 is provided on the outer surface of the end 4B of each divided furnace body so as to close the discharge holes 12. The butterfly-shaped lid 13 is normally in a closed state due to its own weight or the help of a spring mechanism (not shown), but when the internal pressure of the cooling cylinder 8 increases, it is automatically lifted and opened. It is structured as such.

Therefore, the cooling medium blower and the solenoid valve 11. Pipe 10.
Introduction hole 9. The discharge hole 12 and the butterfly-shaped lid 13 constitute forced cooling means.

Note that the above cooling medium is air or helium. Use nonflammable gas such as argon or nitrogen.

2. In the configuration of the first embodiment, after removing the pipe 10 from the split furnace main body that opens around the hinge 3, the test specimen 1 is inserted into the cooling tube 8 with the split furnace main body opened double-sidedly, The pull rods 5A and 5B are attached to it to support the specimen 1, the opened split furnace body is closed again, and the pipe 10 that was previously removed is attached to the furnace body to complete the test preparation.

When the power switch is turned on, the current passes through the heating control device and heats the nichrome wire 7, and the inside of the furnace is gradually warmed up. When the predetermined upper limit temperature of the test temperature cycle is reached, the heating control device receives a signal from the temperature sensor and heats the nichrome wire 7. Then, when the temperature of the specimen 1 falls below the upper limit temperature, the thermostat closes the circuit to the nichrome wire again and starts heating, keeping the temperature of the specimen 1 at a predetermined upper limit temperature.

The air space inside the reactor is divided into the nichrome wire side compartment and the specimen side compartment by a thin cooling cylinder 8 with high thermal conductivity, but it cannot be avoided that there is a slight time lag in tracking the temperature in the side compartment. .

The heating control device, which maintains the upper limit temperature of the specimen 1 for a predetermined period of time, automatically operates to interrupt the circuit to the nichrome wire 5 until the specimen temperature reaches the predetermined lower limit temperature of the test temperature cycle.

Simultaneously with the circuit breaking of the nichrome wire -\, the heating control device sends a signal to the solenoid valve 11 to open the valve 11, and the cooling medium gas from the cooling medium blower is introduced into the cooling cylinder 8 through the pipe 10° introduction hole 9. The hot gas inside the cylinder passes through the exhaust hole 12, pushes up the butterfly-shaped lid 13, and is discharged to the outside of the furnace.

In this way, the inside of the cooling cylinder 8 is cooled fairly rapidly, and then the specimen 1 is cooled down.

Of course, the nichrome wire side section is also gradually cooled down through the cooling cylinder under a certain time lag, but the circumferential area of the cooling cylinder, which is the heat exchange area between the nichrome wire side section and the specimen side section, is compared. The volume of the nichrome wire side compartment is extremely large compared to that of the specimen side compartment, and the side wall 6 of the furnace body, which has a large heat retention capacity, is made of firebrick, etc.
Therefore, the cooling time lag in the nichrome wire side section is extremely large.

When the specimen 1 reaches the above-mentioned lower limit temperature, the heating control device receives a signal from the temperature detection element of the specimen, closes the solenoid valve 11, closes the circuit to the nichrome wire 7, and starts heating the heating furnace again. 5, then move on to the next test temperature cycle.

In the heating process in the second and subsequent test temperature cycles, the temperature of the nichrome wire side section at the start of heating is much higher than that in the first cycle due to the time lag cooling during the cooling process, so it reaches the predetermined upper limit temperature. It will take less time.

Figure 5 shows an example of the second and subsequent test temperature cycles as a solid line. You can see that the time is significantly shortened.

Along with this, the power for operating the device is also significantly reduced.

FIGS. 6 and 7 show a second embodiment of the cooling cylinder configuration, and this cooling cylinder 8' is formed of a spiral segment on the inner periphery of the cooling cylinder 8 of the first embodiment to guide the cooling medium gas. A plurality of fins 14 are provided protrudingly, and the medium gas passing through the cooling cylinder 8' during the cooling process is guided to rotate by the fins 14, thereby eliminating uneven contact with the specimen 1 and enhancing the cooling effect. .

Although not shown, the spiral band of the fins 14 may be extended to form a continuous spiral band along the entire length of the cooling cylinder 8'.

However, this spiral band is designed to be divided into two parts when the cooling cylinder 8' is divided into two parts.

Furthermore, micropores may be provided at several locations in the spiral band to further change some of the streamlines of the medium gas to ensure even contact with the specimen 1, thereby further increasing the cooling efficiency.

In the above embodiment, a nichrome wire was used as the heating means, but the present invention is not limited to the above, and a gas furnace or a heavy oil furnace may be used, for example.

In addition, a pull rod was used as the support mechanism for the specimen in order to conduct tests such as how many test temperature cycles the welded part of the specimen could withstand a predetermined tensile force. Needless to say, it is suitable as a supporting mechanism.

As described above, the present invention is an improved heating furnace with a simple structure in which a cooling tube surrounding the specimen is provided inside the furnace and a forced cooling device is applied to this, while the time of the heating process and cooling process is significantly shortened. In addition to improving work efficiency and saving power, it was also possible to suppress temperature changes in the furnace walls and heating means to a smaller extent than with conventional methods, making it an excellent product that extends the life of these devices. It provided a heating furnace.

[Brief explanation of the drawing]

Figure 1 is a vertical cross-sectional view of a conventional heating furnace, Figure 2 is a typical test temperature cycle diagram for heating and cooling a specimen using a heating furnace, and Figures 3 to 6 are examples of the present invention. 3 is a vertical sectional view of the heating furnace according to the first embodiment, FIG. 4 is a sectional view taken along line IV-IV in FIG. 3, and FIG. 5 is a longitudinal sectional view of the heating furnace according to the first embodiment. Test of the specimen, test temperature cycle diagram, Fig. 6 is a vertical cross-sectional view of the second embodiment related to the cooling cylinder, Fig. 7 is the test temperature cycle diagram.
FIG. 3 is a sectional view taken along line VIVI in the figure. 1: Specimen, 2: Furnace body, 5A, 5B nibble rod (support mechanism), 6: Side wall, 7: Nichrome wire (heating means), 8
．． 8': Cooling cylinder, 9 Introducing 4 flights 10: Pie 11: Solenoid valve, (forced cooling means) 12: Discharge hole, 13: Butterfly-shaped lid.

Claims (1)

[Scope of utility model registration request] A heating furnace provided with a heating means along the inner wall surface of the furnace body and equipped with a forced cooling means for introducing and discharging a cooling medium gas into the furnace, a cooling cylinder surrounding a specimen in the furnace and its support mechanism. A heating furnace with a cooling tube, characterized in that an air space inside the furnace is divided by providing a cooling tube, and the forced cooling means is applied to the specimen and support mechanism system sections.