JPS6349354A - Control apparatus for feeding molten metal quantity in electromagnetic pump type automatic molten metal feeding machine - Google Patents

Abstract

PURPOSE:To simply and exactly control molten metal feeding quantity by driv ing electromagnetic pump based on a signal from a sensor detecting the fluctua tion of molten surface in a heat holding furnace and pouring the molten metal from a pouring hole positioned at higher place than the molten surface. CONSTITUTION:The sensor 24 is composed of a rack 36 having a round electrode 40 at the tip thereof, a motor 32 shifting vertically the rack 36 through a pinion 34, a dog 38 arranged on the rack 36 and a limit switch LSRo...LSRn arranged, so as to work corresponding to molten surface LSo...LSn by the dog 38. The electromagnetic pump 10 is driven based on detected data for each molten surface level and the molten metal feeding time Ti for a i-th position from the highest position is calculated by the equation. In this way, the molten metal feeding quantity is simply and exactly controlled.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a casting machine such as a die-casting machine, and is designed to compensate for changes in the i1'8/A plane in a heat-retaining furnace by changing the hot water supply time. This invention relates to a hot water supply amount control device in an electromagnetic pump type automatic water heater.

[Conventional technology]

For many years, the method of supplying hot water to casting machines was for the foundry worker to draw a certain amount of molten metal using a ladle and pour it into the mold. The problem was how to compensate for changes in static pressure due to changes in the surface of the molten metal and changes in volume within the hot water supply pipes in order to keep the amount of hot water supplied constant. For example, in order to keep the molten metal level in the heat-retaining furnace constant, the molten metal is frequently refilled manually, or the weight of the cast product is measured from time to time, and the electromagnetic pump is used to supply the molten metal to a certain amount. The set timers were sometimes manually adjusted, and automatic control was considered essential.

[Problem that the invention seeks to solve]

Conventional manual work and manual timer setting adjustments were extremely labor-intensive, and automatic control was an essential requirement.

The purpose of the present invention is to provide a simple controller that can control the hot water supply time of the electromagnetic pump by intermittent drive power in response to changes in the molten metal surface during hot water supply, and can provide a constant amount of hot water each time. The present invention provides a hot water supply amount control device for an electromagnetic pump type automatic water heater.

[Means for solving problems]

Therefore, the hot water supply amount control device for the electromagnetic pump type automatic water heater according to the present invention is equipped with an injection sleeve that injects molten metal into the mold cavity by an injection plunger, and the molten metal stored in the heat retention furnace is transferred to the injection sleeve to keep it warm. In an electromagnetic pump-type automatic water heater for a die-casting machine configured to transfer hot water using an electromagnetic pump installed in a part of a hot water pipe connecting the furnace and the injection sleeve, the injection sleeve's pouring port is set at a height higher than the highest molten metal surface of the insulating furnace. Further, a sensor is provided for detecting changes in the surface of the molten metal stored in the heat retention furnace, with the molten metal supply pipe being straight and having the same cross-sectional area within the pipe from the highest point to the lowest point of the molten metal surface; The present invention is characterized in that a controller is provided that corrects and controls the drive time of the electromagnetic pump based on the signal from the sensor.

In the hot water supply amount control device, the controller that corrects and controls the drive time of the electromagnetic pump divides the molten metal surface in the heat retention furnace into n parts from the highest point to the lowest point, and measures each molten metal surface using a level sensor. The electromagnetic pump that controls the amount of hot water is detected by intermittent constant voltage, constant frequency three-phase power, and the driving time is used as the hot water supply time to drive the electromagnetic pump that controls the hot water supply amount. and determine the first point from the highest point sensor.
Based on the signal indicating the molten metal surface, the hot water supply time Ti is calculated using the following formula (%). The correction constant i for the volume change in the hot water supply pipe corresponding to the change in the molten metal surface can be calculated and driven in the molten metal surface area of 1, 2.3, . . . n.

[Effect]

According to the hot water supply amount control device for an electromagnetic pump type automatic water heater according to the present invention, when the molten metal surfaces in the insulating furnace and the hot water supply pipe are at the same level at the highest point, first, the hot water supply time is determined in advance by roughly calculating. Test casting is performed by driving the electromagnetic pump, the properties and dimensions of the cast product are inspected, the hot water supply time is adjusted several times, and the trial casting is repeated to determine the hot water supply time To.

In this hot water supply operation, what changes the amount of hot water supplied is:
This is a change in the actual pumping capacity of the electromagnetic pump due to a change in the volume of the molten metal in the hot water supply pipe and a change in the molten metal level drop in the heat retention furnace. If the correction constant for these changes and the rate of change are β and α, respectively, then the electromagnetic pump supplying time Ti at the i-th molten metal surface from the highest point on the molten metal surface is expressed by the following equation.

Ti= (1+ (i-1) α) To+ (i-1
)β...(1) The sensor that detects the height of the molten metal surface detects i, calculates the hot water supply time Ti using the equation (1), and drives the electromagnetic pump with the calculated value Tn to obtain a fixed amount. You can get a water heater.

〔Example〕

Next, an embodiment of a hot water supply amount control device for an electromagnetic pump automatic feeder/A machine according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is an explanatory diagram showing the structure of an electromagnetic pump type automatic water heater, which is an embodiment of the hot water supply amount control device of the present invention, and the configuration of the hot water supply amount control device. In FIG. 1, reference numeral 10 indicates an electromagnetic pump, 12 indicates a heat retention furnace, 14 indicates a hot water supply pipe, and 16 indicates an injection sleeve. The injection sleeve 16 is connected to the heat retention furnace 12
The molten metal 28 is located at a higher level than the highest point 26 of the molten metal surface stored in the molten metal 20 and is injected into the mold cavity 20 by the injection plunger 18. The hot water supply pipe 14 is straight and has a uniform inner diameter, and communicates and connects the inlet of the injection sleeve 16 with the outlet at the bottom of the warming furnace 12 . The electromagnetic pump 1° is attached to the hot water supply pipe 4 on the outlet side of the insulating furnace 12, is driven by a three-phase AC power source via the controller 22, and applies thrust to the molten metal flowing in the electromagnetic pump IO using the principle of a linear motor. give. In FIG. 1, an electromagnetic pump 10
When activated, the molten metal 28 is pushed up by the thrust and the pressure caused by the head of the molten metal surface in the heat retention furnace I2, and the injection sleeve 16
supplied within. As die casting is repeated, the surface of the molten metal in the heat insulating furnace 12 gradually shifts to a lower point and changes. A sensor 24 is provided to measure this change. This sensor 24 can be used by floating a float, by using electrodes, or by using various level measuring devices such as a radio wave or ultrasonic level meter, but in this embodiment, a sensor that mechanically moves a probe needle up and down will be explained. do. The controller 22 controls the power supply based on a level signal indicating a change in the molten metal level from the sensor 24, and increases the hot water supply time, which is the drive time of the electromagnetic pump 10, as the number of hot water supply increases and the molten metal level decreases. , to ensure a certain amount of hot water supply.

Next, in such a hot water supply amount control device, how to set the hot water supply time so that the water heater can supply a constant amount of hot water each time will be explained. What changes with each hot water supply operation is the surface of the molten metal in the heat retention furnace 12 and the hot water supply pipes 14.

Now, let the highest point of the molten metal surface be Lso and the lowest point Lsn, and divide the interval between these two points into n equal parts, and each molten metal surface Ls+, Ls
2...L s (n-1) is determined. The volumes Δ■ of the hot water supply pipe 14 divided into n parts by the molten metal surfaces in the hot water supply pipe 14 that are at the same level as each of these molten metal surfaces are all equal.

In order to supply hot water in a state where the molten metal level has dropped from the highest point Lso in scene f6 to the molten metal level Lsi, it is necessary to replenish the molten metal corresponding to the volume Δvxi. Therefore, if the pumping capacity when the electromagnetic pump 10 is driven with a predetermined current is the flow rate Q for a single time, then △'l/ x i / Q = β x j seconds is added to the initial hot water supply time. This is the correction by β, which is β-ΔV/Q. On the other hand, with respect to changes in the molten metal surface in the heat retention furnace 12, since the pumping capacity of the electromagnetic pump 1o when driven with a predetermined current is constant at the flow iQ,
The change in pressure corresponding to the change in the /8 melt level head in the heat retention furnace 12 is the change in the actual pumping capacity of the molten metal.

Therefore, for example, when the molten metal surface is between Ls□ and Ls+, try casting the electromagnetic pump 10 with the drive time set to To, inspecting the cast product and confirming that it is properly feeding the hot water by repeating it several times. Determine TO.

The scene is detected by the molten metal surface sensor, and the water supply time Ti-(1+ (i-1) α) To-1-(i-1
)β? If the electromagnetic pump 10 is driven for the hot water supply time 'Fj, the amount of hot water for a predetermined amount can be increased by 1+i/2 each time.

FIG. 2 is an explanatory diagram of the relationship between the molten metal supply time Ti and the molten metal surface, and shows that the molten metal supply time Tn increases stepwise as the molten metal surface Lsn decreases.

FIG. 3 is an explanatory diagram showing the structure of the sensor 24 shown in FIG. 1. In FIG. 3, the sensor 24 includes a rack 36 having a round bar-shaped electrode 40 at its tip, and an electric motor 32 that raises and lowers the rack 36 via a pinion 34.
A dog 38 provided on the rack 36, and a limit switch LSRO provided to be activated by the dog 38 in response to the molten metal surfaces Lso, Ls1, . . ., Lsn.

It is composed of LSR+...LSRn. The dog 38 is configured so that the limit switch is not activated when the rack 36 is lowered, but is activated only when the rack 36 is raised. The heat-retaining furnace 12 has a conductive ceramic electrode 44 extending from its opening to the bottom.
A battery 42 and a relay LVR are provided between the electrode 44 and the electrode 40 to connect them to each other. Therefore, electrode 4
0 descends and contacts the highest point 26 of the molten metal surface, first, the ON operation signal of the relay LVR is input to the logic control circuit 46 of the controller 22. Next, the electrode 40 rises and contacts the limit switch LSRO, and the ON operation signal of the limit switch Lso is input to the logic control circuit 46. Controller 2
In addition, relays MRR and MR for switching the electric motor 32 up and down, and a current switch ESR, such as a tritic, for intermittent operation of the electromagnetic pump 10, are built into the pump 2.

FIG. 4 is a circuit diagram of the logic control circuit 46 shown in FIG. 3. In Fig. 4, when the push button switch for hot water supply preparation command SPR is operated, an ON operation signal is input to AND gate 1 (hereinafter referred to as ADI) via OR gate 5 (hereinafter referred to as OR5), and an ON operation signal from relay LVR is input. When there is no output, the output of relay MR is on, and the motor 32
rotates in the downward direction, and the electrode 40 comes into contact with the molten metal surface. With this contact, the ON operation signal of the relay LVR is transmitted to the AND gate ADI via the NOTOR gate 5 (hereinafter referred to as NTI).
, the output of relay MR turns off, electrode 40 stops, and AND gate AD2 starts timer Tx of the output circuit. The electrode 40 remains in a stopped state for several seconds, and when the timer Tx eventually times out, the AND gate AD7 turns on the output of the relay MRR, and the motor 32 starts rotating in the upward direction. Eventually, when the limit switch L SRO is activated by the dog 38, its operation signal Lso is turned on, and the flip-flop 1 is turned on.
(hereinafter referred to as FF1) turns off the relay MRR output of AND gate AD7, so motor 32 stops. Next, when the push button switch of the hot water supply command SAR is operated, the output signal of the flip-flop FF5 to the current switch ESR via the flip-flop FF6 is turned on, driving the electromagnetic pump 10, and outputting the AND gate AD3. Circuit timer TMo (setting time T.

) starts. When the timer TMo times up after the required time To, the output of the AND gate AD8 is turned off, the output signal of the flip-flop FF5 to the electromagnetic switch ESR is turned off, and the electromagnetic pump 10 is stopped. At the same time, flip-flop FF
The other output of 5 is turned on and the AND gate AD
The output signal to the relay MR is turned on, and the electrode 40 starts to descend. In this way, the signals Ls1°Ls2. that detect the molten metal surface. ...Lsi・
...The electromagnetic pump 10 runs a preset timer TMO each time Lsn is input.

TM+, TM2...operating time of TMn, that is, hot water supply time T, , T2, 'r3...
Execute hot water supply of Tn. Finally, the hot water supply operation is completed by operating the push button switch for the hot water supply prohibition command SOR. Note that such operations can be performed in exactly the same way using a computer.

When using a computer, TMO, TM+, . . . TMn can be automatically set by calculating Ti in the equation (1).

In general, in die casting, the casting cycle is around 30 seconds, and the hot charging interval to the insulating furnace is 30 to 60 minutes, so for example, 60 to 120 products can be produced in one hot charging. Ru. For this reason,
In the present invention, the number of times n of detection of the molten metal surface in the heat retention furnace is n=
Setting n to 60 to 120 is actually complicated, and there is no need to set the number to be that large; usually, n=10 or so is sufficient. In this case, if the control accuracy is insufficient, the scene detection electrode is returned to the predetermined level at which the scene was detected each time for each preset detection point, and then the electrode is returned to the predetermined level at which the scene was detected each time. By lowering the electrode and detecting the hot water level, it is possible to detect, for example, the time it takes for the electrode to detect a scene from a predetermined level, and to make corrections for the actual scene.

〔Effect of the invention〕

As is clear from the embodiments described above, according to the present invention,
Even if the molten metal level in the insulating furnace changes, it is possible to supply a fixed amount of hot water, making it possible to completely automate the process.

Furthermore, the electromagnetic pump is driven with constant voltage and constant frequency,
The intermittent operation that ensures hot water supply time is inserted in series with the load, and a simple current switch such as a triac is sufficient, and it does not require voltage adjustment using phase control or the like, and can be manufactured at low cost. can.

Although the preferred embodiments of the present invention have been described above, it goes without saying that various design changes can be made without departing from the spirit of the present invention.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an embodiment of a hot water supply amount control device in an electromagnetic pump type automatic water heater according to the present invention, and FIG. 2 is a characteristic diagram showing the relationship between hot water supply time Ti and molten metal surface in the present invention. 3 is a structural explanatory diagram of the sensor shown in FIG. 1, and FIG. 4 is a circuit diagram of the logic control circuit shown in FIG. 3. io,, electromagnetic pump 12. , , heat retention furnace 14
,,, Hot water pipe 16. , , injection sleeve 1
8. Injection plunger 20. ,, mold cavity 22),, controller 24. ,,sensor 26,
,,highest point on the molten metal surface

Claims (2)

[Claims] (1) An injection sleeve is provided for injecting molten metal into the mold cavity by an injection plunger, and a part of the hot water supply pipe connecting the insulating furnace and the injection sleeve is provided with the molten metal stored in the insulating furnace for the injection sleeve. In an electromagnetic pump-type automatic water heater for a die-casting machine configured to be transferred by an electromagnetic pump, the pouring port of the injection sleeve is located higher than the highest molten metal surface of the insulating furnace, and the surface of the molten metal stored in the insulating furnace changes. 1. A hot water supply amount control device for an electromagnetic pump type automatic water heater, characterized in that a sensor for detecting the above is provided, and a controller is provided for correcting and controlling the driving time of the electromagnetic pump based on a signal from the sensor. (2) In the hot water supply amount control device according to claim 1, the controller that corrects and controls the driving of the electromagnetic pump divides the molten metal surface in the heat retention furnace into n parts from the highest point to the lowest point. The surface of each molten metal is detected by a level sensor, and constant voltage, constant frequency three-phase power is applied intermittently to drive the electromagnetic pump that controls the amount of hot water supplied using the driving time as hot water supply time. Determine the hot water supply time To at the highest point on the molten metal surface, and calculate the hot water supply time Ti using the signal from the highest point level sensor indicating the i-th molten metal surface using the following formula Ti={1+(i-1)α}To+ (i-1) β...
(1) However, α is a constant that indicates the rate of change in the actual pumping capacity of the electromagnetic pump due to changes in the molten metal surface in the heat retention furnace; β is a correction constant for volume changes in the hot water supply pipes corresponding to changes in the molten metal surface in the heat retention furnace; i is a hot water supply amount control device in an electromagnetic pump type automatic water heater configured to operate by calculating in 1, 2, 3...n molten metal surface areas.