JPS5920631Y2 - Heat treatment furnace with preheating function - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a heat treatment furnace having a preheating function that can preheat a substitute product waiting to enter the furnace.

Conventionally, when preheating a product before it is charged into a heat treatment furnace, a furnace body exclusively for preheating is installed in front of the heat treatment furnace, and exhaust gas from the heat treatment furnace is piped to this as a heat source, and the product is transported into the furnace. As a result, the substitute product was preheated.

However, the above-mentioned preheating furnace requires the installation of a new furnace body, which also requires incidental equipment such as product conveyance equipment and exhaust gas supply/discharge piping. However, the equipment cost was extremely high, making it unsuitable for energy saving investment in heat treatment furnaces.

This idea aims to solve the above problems,
The present invention proposes a heat treatment furnace having a preheating function, which is characterized by being able to preheat products waiting to be placed in the furnace using inexpensive equipment.

An embodiment of this invention will be described below with reference to the drawings.

As shown in FIGS. 1 and 2, the charging door 4 of the heat treatment furnace 3
A long exhaust gas hole 1 for preheating the finished product is bored along the bottom of the charging door 4 at the lower furnace front at the height of the finished product.

A hood 2 for collecting exhaust gas is disposed above the front surface of the charging door 4.

The hood 2 has the shape of a lower floor, and its lower end is lowered to a height that does not touch the products, and is supported and hung vertically on the furnace frame 5, and its upper end, which is equipped with suction equipment such as a fan, is heat-treated. It is configured by connecting to the existing flue (not shown) of the furnace 3.

Reference numeral 6 denotes a product transport platform connected to a drive device 7 for continuous transport, which transports the products by sliding on a pair of left and right rails 8.8.

Reference numeral 9 indicates a driving device for the charging door, and reference numeral 10 indicates a seal plate attached to the furnace frame 5.

Now, when preheating substitute products in the heat treatment furnace, each product 11 to be heat treated is transferred in sequence on the product transfer table 6 in rows, as shown in FIG. After stopping at the front and waiting for a certain charging time, the product is charged into the furnace together with the finished product carrier 6.

At the same time as this charging, one substitute product is extracted from the extraction port along with the finished product conveyance table 6.

During such a continuous product conveyance process, the exhaust gas burned in the furnace is discharged to the outside through the flue, while the exhaust gas is also continuously discharged from the long exhaust gas hole 1 newly drilled in the charging door 4. Exhaust gas is ejected from the exhaust gas hole 1 and directly hits the product 11, which is waiting to be loaded into the furnace and is about to be charged, which faces the exhaust gas hole 1 at the same height, and moves upward in an upward flow to collect the exhaust gas. is sucked by the hood 2 and guided to the flue.

However, since the temperature of the finished product 11 immediately before charging, to which the exhaust gas is applied, is gradually increased by the retained heat of the exhaust gas, only the substitute product immediately before charging is efficiently preheated.

Next, when this product is charged into the furnace, the product can be heated from the preheating temperature in the heat treatment furnace 3, thereby reducing the fuel consumption of the heat treatment furnace and shortening the time in the furnace until the predetermined heating temperature is reached.

In addition, since the exhaust gas for preheating is sucked by the hood 2, it does not flow around the outside of the furnace, and the environment will not be deteriorated.

Furthermore, since the amount of exhaust gas ejected from the exhaust gas hole is small, it does not have any adverse effect on the interior of the furnace.

Although the exhaust gas hole 1 is shown as one elongated hole, the exhaust gas hole is not limited to this, and may be divided into several elongated holes, for example, to form an exhaust gas hole that matches the shape of the substitute product.

In addition, although this invention shows a continuous transfer type heat treatment furnace, it is not limited to this heat treatment furnace, but any furnace of the in-furnace transfer type that continuously performs the steps of charging, heating, and extracting the product can be used. Easy to apply.

Fig. 3 shows the results of actually preheating a substitute product using the above heat treatment furnace.

In other words, a crank shirt I with a length of 1.27 m and a weight of 186 kg was used as a finished product, and the temperature was 7.5 m at the furnace front position of the charging door.
Each piece was charged into the furnace one by one at a charging waiting time A of minutes.

Note that B indicates the outside of the furnace, and C indicates the inside of the furnace.

During that 7.5 minutes, a cross section of 100 mm x 7
Exhaust gas at 550°C from inside the furnace was continuously blown onto the crank shirt 1 through an exhaust gas hole drilled at a diameter of 0.00 mm.

As a result, crank shirt 1~ is 25°C to 60°C.
The temperature rose to

Then, it is charged into a heat treatment furnace at 550°C, which is necessary for heat treatment.
The temperature was raised to a similar level and the crankshaft was heat treated.

As a result, it was possible to reduce the fuel consumption by about 6% of the fuel required for the heat treatment furnace due to preheating.

In addition, the time in the furnace for each finished product was reduced by about 8 degrees compared to the current product.

As mentioned above, this idea has an exhaust gas hole for blowing out in front of the furnace in the charging door so that the product can be preheated successively in front of the manufacturing staff in the furnace, so that the preheating operation of the substitute product can be performed in the heat treatment furnace itself. Moreover, the role of the preheating function can be accurately fulfilled with inexpensive modified equipment that simply forms an exhaust gas hole and provides a hood for recovering the exhaust gas as the preheating equipment.

Furthermore, by using the exhaust gas from the heat treatment furnace as the heat source, fuel for preheating can be omitted, and since the product is preheated in the furnace, fuel consumption can be reduced, and fuel costs can be reliably reduced.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal side view showing an embodiment of this invention, Fig. 2 is a front view showing an embodiment of the exhaust gas hole of this invention, and Fig. 3 is a diagram showing the temperature and time of the product in an embodiment of this invention. This is a diagram showing the relationship. 1... Exhaust gas hole, 2... Hood, 3... Heat treatment furnace, 4... Charging door.

Claims (1)

[Scope of utility model registration request] An exhaust gas hole 1 is bored at the bottom of the charging door of the heat treatment furnace at the height of the furnace preform product along the bottom of the charging door, and a hood 2 for collecting exhaust gas is arranged above the front of the charging door. A heat treatment furnace with a preheating function in which the upper end of the hood is connected to the flue of the heat treatment furnace.