JPS5914293A - Temperature controller for induction heating vacuum melting furnace - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a temperature control device for an induction heating vacuum melting furnace.

Conventionally, induction heating vacuum melting furnaces using high frequency power sources have been known, but temperature detection and high frequency power sources have not been organically linked and controlled. Also, since the melting temperature is extremely high, temperature detection methods are limited, so the temperature can only be monitored. hole.

Furthermore, due to limitations on processing time, heating during operation is not necessary.
(The power input to the coil was not controlled, but the sieve frequency power source was primarily controlled. As a result, there was a large variation in the temperature of the tapped metal poured into the mold, making it unusable for castings after molding.) There were a lot of things involved, and quality control required a lot of effort.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a temperature control device for an induction heating vacuum melting furnace that can obtain a stable tapping temperature without requiring special operations.

In order to achieve the above object, the present invention detects the temperature of a material to be melted in a non-contact manner using a temperature sensor, and stores the detected temperature data in a predetermined thermal fatigue control program and a power control program. The above program is executed based on the temperature data in this control circuit to control the Kosho Wave power supply, and in addition to responding to the temperature data, it also produces optimal hot water supply with the minimum amount of power used from the perspective of energy saving. The temperature was set to K to obtain the desired temperature.

Embodiments of the present invention will be described in detail below with reference to the drawings.

, - FIG. 1 shows a block diagram of an embodiment of the present invention.

The control unit 1 is manually inputted via the digital output unit 3 with the value of the outlet temperature suitable for the material to be melted 9, which has been preset by the external command unit 4.

Further, the state of the high frequency power source 6 is input to the control section 1 via the digital output section 3. This system (finance) department 1 is
It is determined whether operation is possible based on the state of the high frequency power source 6, and only when it is determined that operation is possible, a command is sent to the high frequency power source 6 via the analog human output section 2 based on a command from the external command section 4. The operation of the high frequency power source 6 is started, and the heating coil 7 is heated to heat the material to be melted 91 in the vacuum melting furnace 8 .

Of the material to be dissolved 9? M& is detected by a non-contact temperature sensor 10 attached to the vacuum melting furnace 8, and is manually inputted to the control unit 1 via the temperature converter 11 and the analog input/output unit 2. Then, the control unit 1 compares the value preset by the external command unit 4 with the current temperature detected by the temperature sensor 10 to determine whether the temperature is controlled or not. MI? At the same time, the time chart of FIG. 2 and the 70-chart of FIG.
Trace and explain.

First, in step 101 of FIG. 3, initialization is performed, and in step 102, it is determined whether or not operation is possible. If the operation is possible, 1. Give an operation start command to the high frequency power source 6, and operate the high frequency power source at full power to melt in the shortest time (V Cmal
driving). Subsequently, in step 104, temperature IW detection is continued by the temperature sensor 10, in step 105 it is determined that a predetermined time has elapsed, and in step 106 it is determined whether the temperature T of the material to be melted has reached the set temperature T@. . When the temperature T reaches the set temperature T11, the high frequency power source 6 is operated at minimum power in step 107 (VCm1m operation), and a dissolved photon display is output to the monitor unit 5 in step 108.

After that, the temperature is monitored in step 109, and step 1
At step 10, the temperature T has reached the maximum value fr□8, but at step 111 it is determined again whether or not pouring is being performed, and at step 112 it is determined whether the temperature T has reached Ts - gVc. If the temperature T is equal to or lower than Ts-α in step 112, then in step 113 an optimum power (vcN operation) between the Vcm8 operation and the VC@I11 operation is performed. Furthermore, the temperature is monitored at step 114, and at step 115, the temperature T reaches the maximum value T,...! In step 116, it is determined whether or not to pour the molten metal. In step 117, the temperature T is T1+.
Determine whether or not it has reached α. In step 117 the temperature T
When becomes equal to or greater than TII+α, VCwarm operation is performed in step 118, and the process returns to step 109.

By doing as above, the temperature T1-α.

The operating conditions are alternately changed at TII 10α (Ye
n operation, VCm 1m operation), the temperature of the hot water until pouring is controlled to be kept within the allowable range. In this case, while monitoring the temperature, the rate of temperature rise is also measured at the same time, and the optimal V
c)l, Vc 111111 is selected and operated. Furthermore, since there is a lag time until the temperature changes, we have created an algorithm that fully takes into account the time delay of temperature detection so that over/neat and undershoot of temperature changes do not exceed the allowable temperature range. In addition, as part of its leg-holding function, if temperature control becomes impossible, the high-frequency power supply is shut down to prevent equipment damage.

According to this embodiment, the optimal Vc)J, VcII
Since the operation is performed while selecting the IM, even if the amount of the material to be melted changes, the input power of the high river wave power source is automatically changed, so that efficient operation can be achieved.

In addition, in the above explanation, if the weight of the material to be melted is input as a parameter from the external command unit, measurement of the temperature rise rate and selection of V'c N and Vc m1m are unnecessary, and the program can be simplified. .

In addition, as shown in the time chart in Figure 2, the state of the material to be melted changes between solid phase, solid-liquid phase mixture, and liquid phase, but the inductance of the heating coil changes during this time. Therefore, more efficient operation is possible by appropriately controlling the output lht pressure and subflow of the high frequency power supply.

As explained above, according to the present invention, the time required for melting is shortened, and the temperature of the hot water poured into the mold is constant, which improves the quality of the products and makes it possible to save labor in quality control. By doing so, the efficiency of power usage will be improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a time chart of the operation of the embodiment, and FIG. 3 is a flowchart of the operation of the embodiment. 1...Control unit, 2...Analog input/output unit, 3...
Digital human output unit, 4... External command unit, 5... Monitor unit, 6... High frequency power supply, 7... Heating coil,
8... Vacuum melting furnace, 9... Material to be melted, 10... Temperature sensor, 11... Temperature converter, Vc... Command voltage, W... Allowable temperature range, 10th 2nd口■ Hirom 475- Figure 3

Claims (1)

[Claims] 1. A high-frequency power supply that supplies power to a heating coil that heats a furnace for melting the material to be melted, a temperature sensor that detects the temperature of the material to be melted without contact and outputs a temperature signal, and a predetermined temperature control A temperature control device for an induction heating vacuum melting furnace, comprising a control circuit that stores a program and a power control program, executes the program based on the temperature signal, and outputs a control signal to the high frequency power source.