JPS59123749A - Controlling method of soaking furnace for aluminum casting ingot - Google Patents

Abstract

PURPOSE:To decrease fuel consumption in a soaking furnace for indirect heating of an Al casting ingot provided with a damper by controlling the opening and closing of the damper under a specific condition thereby regulating the flow rate of fuel. CONSTITUTION:An Al casting ingot contained in a furnace is heated at the fuel flow maintained at a specified rate with respect to said ingot while the quantity of the hot wind to be circulated in the furnace is limited. The limitation for the quantity of the hot wind is released when the furnace temp. attains 300-400 deg.C, then the flow rate of the fuel is increased to maintain the monotonous increase of the furnace temp. thereby maintaining the fuel flow at a specified rate. The fuel flow is returned to the original specified rate and the ingot is heated in the stage of having no need for limiting again the quantity of the hot wind with an increase in the furnace temp. The fuel is again increased and the ingot is heated at the specified fuel flow rate just before the prescribed furnace temp., that is, at the point when the gradient of the heating curve decreases and the fuel is minimized on approaching of the heating capacity to a threshold.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention aims to reduce the fuel consumption required for heating when aluminum ingots are charged into a homogenizer and heated, and also enables the reduction of 1ifl during heating, resulting in so-called energy saving. [
The purpose is to contribute to Conventionally, ingots at room temperature are housed in parallel in a soaking short circle, and the generated hot air is directly or indirectly introduced between the rows of ingots to completely heat them, and the aluminum ingots are heated. A heating method is used in which the temperature of the hot air is raised, and then the air is heated again and circulated. However, at the initial stage of heating, the furnace temperature is low, and the specific gravity of the hot air is therefore high, which reduces the load on the circulation fan's drive motor. If the upper limit of the rated value is exceeded, the motor life will be significantly shortened, so as a protective measure, the circulating air volume should be limited until a certain furnace temperature is reached and the motor load remains within the rated value. For example, measures such as tightening the fan damper to limit the amount of air flow are being taken.

However, after that, the furnace temperature is increased and the specific gravity of the hot air becomes smaller after reaching a predetermined temperature.There is no need to limit the amount of hot air and the damper is opened, so the newly increased air volume is compared to the previous one. Since heat exchange with the energized aluminum ingot is promoted, the furnace temperature temporarily decreases, and the above-mentioned ship air volume restriction becomes necessary again. Thereafter, the above-mentioned heat W x limit and cancellation will be repeated, leading to an extension of the heating time and an accompanying deterioration of the basic unit. This phenomenon is particularly noticeable when the amount of fuel input is limited from the point of view of energy saving.

The present invention provides a method for controlling a soaking furnace, which aims to reduce the consumption cost required for full-wire heating, which has the drawbacks mentioned above.

If we explain it based on an example of a diagram showing the relationship between temperature and hour, first of all, Hama 1 diagram is 1 traditional, γ ago, and the horizontal axis is time 1.
)1'! The graph shows the progress: TF1...Temperature at which the damper is set to open/close TF1''...The temperature at which the damper is opened and the fuel flow rate is at full capacity. Temperature TF at which it does not close, '...Increase the amount of fuel to fully open the damper - Grease leakage Figure 2 shows all of the above relationships with the vertical axis of the total fuel flow rate V and the horizontal axis of time. , and Tp,' corresponds to the starting temperature at which the fuel flow rate increases from Vl to V-[, and T F , // corresponds to the temperature re-stringing flow rate at the end point of the temperature and the same flow rate of Vl. The damper is at the open position.In the above embodiment, heating is performed under a constant fuel flow rate from 1 to 1 with the damper closed, and the furnace temperature rises along the curve, T F In the state of , /, the hot air flow rate is still required to be restricted, so the titanium par k'' is made similar to the closed state.At this time, at point P, the fuel flow rate increases to vl, and the furnace temperature as a whole follows the rising curve H. Next, damper 1 reaches the opening/closing set temperature TF, and the furnace temperature reaches the "open" state.Furthermore, in the "open" state, the damper opening/closing set temperature '1' is reached.
'F, return the fuel flow rate to VIll, which is the same as the original constant flow rate, with the lower i7u. Next, the predetermined furnace temperature Ki
Consumption immediately before consumption: At the point where the beverage reaches its minimum, the fuel flow rate is increased to V■ again and the temperature is soaked.

According to the present invention, the above-mentioned configuration has achieved a reduction in the amount of energy required for heating, and a reduction in heating time of approximately 10%.

[Brief explanation of the drawing]

Figure 1 is a graph showing the relationship between furnace temperature and time according to the present invention, and Figure 2 (ζ is a graph showing the relationship between fuel flow rate and time corresponding to Patent applicant: Sumitomo Light Metal Industries, Ltd. =--] Agent: Joint venture.

Claims (1)

[Claims] Indirectly heated aluminum i47 with mites/bars
In jJ soaked noodles, the air volume for the circulating beak in the Tsukuda is 1A based on the constant flow rate of 5) for the stored aluminum ingot! ! It: I'm going to join in, and I'm going to join in. 'Akira (l
When the temperature reaches 800 to 400, the restriction on Δr4iJ is resolved and the furnace temperature does not rise by 1. There is no need to restrict the hot air flow again. Constant flow rate (l
Taking this into account, the temperature rises to the point just before the predetermined temperature, that is, when the slope of the temperature rise curve becomes small, the point at which the attractiveness of the −f+temperature approach approaches its limit and the number of available beverages becomes the minimum. A control method for soaking and controlling aluminum ingots, which is characterized by heating at a constant flow rate of twisting materials.