JPH05212490A - Method for adjusting kneading of molding sand and device therefor - Google Patents

Abstract

PURPOSE:To grasp kneading condition of kneaded sand, control pouring water quantity and enable kneading adjustment of the molding sand with high accuracy by measuring the sand height during kneading, analyzing variation of the sand height and estimating the compactibility value. CONSTITUTION:Recovered sand is charged in a kneading vessel 1, and a motor 2 is driven and also, the first water pouring is executed. Bentonite in the kneaded sand absorbs moisture and swells, the vol. of the sand is increased and the upper end of the kneaded sand is risen. The height of the kneaded sand is measured by an ultrasonic distance sensor 10 with time. At the time when the height of the kneaded sand stabilizes, the value preset from the relation between the sand height and the compactibility value is comparison- calculated with the measured sand height. In the case the measured sand height value is lower than the preset sand height value, the short water quantity is calculated according to this comparison and signal is transmitted to a water pouring device 11 and the additional water pouring is executed. When the measured sand height becomes the set value and stabilizes, a signal is transmitted to a controller 13 to complete the kneading work.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding sand kneading adjusting method and apparatus for kneading a molding sand containing bentonite while adding water to prepare the molding sand.

[0002]

[Prior art and problems] Generally, in the adjustment of the kneading of foundry sand, a shortage of water is added to the foundry sand to knead it. It is known that the kneading power of the device is used to determine the current value during kneading, but the accuracy is poor, and there are problems such as the current value changing depending on the friction state of the kneading device and the type of sand. there were. On the other hand, in order to improve the accuracy, the molding sand that is being kneaded is sampled from the kneading device, the compactability (tampering property) value of this molding sand is confirmed, and a device that adds and injects the insufficient amount of water (Japanese Patent Publication 1- No. 15825) is publicly known. However, in order to collect the molding sand during kneading, the auxiliary equipment becomes complicated and the maintenance and inspection of the equipment is difficult, and it takes time to check the compactability and calculate the amount of water shortage. After all, there was a problem that the kneading adjustment time was extended. The present invention has been made in view of the above problems, quickly and accurately by a simple auxiliary equipment to detect the insufficient water amount of the casting sand during kneading, casting that can control the amount of water injection and can perform kneading adjustment It is an object of the present invention to provide a method for kneading sand and a device therefor.

[0003]

In order to achieve the above object, in the present invention, firstly, attention was paid to a compactability value which is a representative index representing the properties of foundry sand. That is, the deposition of foundry sand in the kneading tank changes depending on the bulk density of the sand,
It is well known that there is a unique relationship between the bulk density and the compactability value (hereinafter referred to as CB value). From this, it is considered that there is a correlation between the sand volume and the CB value. Therefore, the casting sand during kneading is not sampled, and the sand height during kneading, which has a unique relationship with the sand volume, is measured to determine the sand height. The amount of water injection is controlled by analyzing the change in water content and estimating the CB value to grasp the kneading state of the kneading sand.

[0004]

Embodiments of the present invention will now be described in detail with reference to the drawings. (Embodiment 1) In FIG. 1, a rotating shaft 3 rotated by driving a motor 2 is erected vertically in a batch type kneading tank 1, and the rotating shaft 3 rotates vertically in the vertical direction. The enabled rotating wheels 4, 4 are pivotally supported via wheel support arms 5, 5. Arms 7, 7 for supporting the scraper 6 and the like are provided at an upper position of the rotating shaft 3, and the arms 7, 7 on the side wall of the kneading tank 1 are provided.
A proximity sensor 9 is provided at a position higher than the height position of 7 through a bracket 8. An ultrasonic distance sensor 10 and a water injector 11 are disposed above the kneading tank 1, and the ultrasonic distance sensor 10 is electrically connected to a calculator 12 of a computer so as to output an electric signal. ing.

The proximity sensor 9 is a rotating arm 7
Is electrically connected to the computing unit 12 so as to output a synchronizing signal when is positioned immediately before the ultrasonic sensor 10. By inputting this signal to the computing unit 12, the rotation is synchronized (in 2 to 4 seconds). Once), signal processing is performed to obtain a sand height signal by the ultrasonic distance sensor 10. Further, the calculator 12 is electrically connected to the water injector 11, and the calculator 12 calculates the sand height from the distance from the lower end to the upper end of the kneaded sand measured by the ultrasonic distance sensor 10, and calculates this. When analyzed over time, when the sand height stabilizes at a value lower than a preset sand height value, a signal from the calculator 12 is transmitted to the water injector 11 for additional water injection. The arithmetic unit 12 is the controller 1 of the device.
3 is electrically connected, and when the sand height of the foundry sand during the kneading is stable at a preset sand height value, a signal is sent to the controller 13 of the apparatus to terminate the kneading and to adjust the kneading sand. It is designed to be discharged.

[0006] With the above-mentioned structure, the recovered sand is put into the kneading tank 1 to drive the motor 2 and perform primary water injection. As a result, when the water by the primary water injection is dispersed, the bentonite of the kneading sand absorbs water and swells.
Along with this, the volume of sand increases, and the upper end of the kneading sand rises. The sand height of the kneaded sand was measured with the ultrasonic distance sensor 10 over time, and when the change in the sand height became stable, a value preset from the relationship between the sand height and the CB value and the measured sand height were obtained. When the measured sand height value is lower than the set sand height value, the amount of insufficient water is calculated accordingly and a signal is sent to the water injector 11 to inject the amount of insufficient water, and additional pouring is performed. To do. After repeating the additional water pouring in this way, when the measured sand height value becomes the set sand height value and becomes stable, a signal is sent to the controller 13, the kneading operation is completed, and the kneading adjustment sand is discharged.

(Embodiment 2) In FIGS. 2 and 3, a rotary shaft 23 which is rotated by the drive of a motor 22 is erected vertically in a batch type kneading tank 21.
The rotating wheels 24 and 2 are vertically rotatable.
4 is pivotally supported via wheel support arms 25, 25. Arms 27, 27 for supporting the scraper 26 and the like are provided at an upper position of the rotary shaft 23, and a cylinder 28 is attached to the arm 27 so as to be vertically oriented. A bar member 30 having a flat plate 29 fixed to the upper end thereof is vertically movably inserted into the cylindrical body 28, and the lower end of the supporting arm 27 is located at a position distant from the cylindrical body 28. The upper position of the sled plate 31 which reaches the lower position of and is bent upward is rotatably supported by the shaft. Further, the lower position of the sled plate 31 and the lower end of the rod 30 are connected by a wire 32.
As the lower position of the sled plate 31 moves up and down, the wire rod 32,
The flat plate 29 moves up and down through the rod 30.

Further, an ultrasonic distance sensor 33 and a water injector 34 are arranged above the kneading tank 21, and the ultrasonic distance sensor 33 outputs an electric signal to a calculator 35 of a computer. It is electrically connected. The calculator 35 is electrically connected to the water injector 34, and the calculator 35 calculates the sand height from the height value of the flat plate 29 measured by the ultrasonic distance sensor 33, and calculates this over time. When the sand height is stabilized at a value lower than the preset sand height value, the calculator 35 sends this signal to the water injector 3
It is sent to No. 4 for additional water injection. Further, the arithmetic unit 35 is electrically connected to a controller 36 of the apparatus and sends a signal to the controller 36 when the sand height of the foundry sand during kneading is stable at a preset sand height value. The feeding and kneading is completed, and the kneading adjustment sand is discharged.

With the above-mentioned structure, the recovered sand is put into the kneading tank 21 to drive the motor 22 and perform the primary water injection. When the water by the primary water is dispersed by this, the bentonite of the kneaded sand is formed. Absorbs water and swells. Along with this, the volume of sand increases and the upper end of the kneading sand rises, pushes up the sled plate 31, and raises the flat plate 29 via the wire rod 32 and the rod member 30. This rising distance is measured by the ultrasonic distance sensor 33, and the same operation as in the first embodiment is performed. The result of actual measurement of the relationship between the sand height value and the CB value kneaded by using the apparatus of Example 2 is shown in FIG. 4, and the relationship between the current value A and the CB value of the apparatus during kneading was actually measured. The results obtained are shown in FIG.

From FIGS. 4 and 5, it can be confirmed that the relationship between the kneading sand height and the CB value is deeper than the relationship between the current value and the CB value. Further, 500 cc of water was first injected into the recovered sand charged in the apparatus of Example 2, kneading was started, and the sand height of the kneaded sand when 200 cc of water was additionally injected after 2 minutes was measured, FIG. 6 shows the results of processing by the calculator 35 and the change with time of the CB value when measured with a conventional apparatus that samples sand every fixed time and measures the CB value. Here, the sampling frequency of the kneaded sand was about every 20 seconds because of the sand sampling time and the compression time (CB value measurement time), whereas the apparatus of Example 2 can measure once every 1.4 seconds. A subtle change in the kneading sand height could be detected, and the kneading condition could be grasped quickly. Further, although the ultrasonic distance sensors 10 and 33 are used to measure the sand height in the embodiment, other non-contact type distance sensors such as a laser sensor and a microwave sensor may be used.

[0011]

The present invention measures the sand height of the kneading sand during kneading as is clear from the above description, and grasps the kneading state of the kneading sand from the correlation between the sand height and the compactness value, Since the kneading adjustment is performed by controlling the water injection for the insufficient amount of water, the kneading adjustment of the foundry sand can be performed quickly and accurately, and the simple structure makes it easy to maintain and inspect the equipment. And the effect of contributing to this industry is enormous.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing a second embodiment of the present invention.

FIG. 3 is a detailed view of an enlarged view of a portion A in FIG.

FIG. 4 is a graph showing the relationship between kneading sand height and compactability value.

FIG. 5 is a graph showing the relationship between the current value of the kneading device and the compactability value.

FIG. 6 is a graph showing the measurement status of the sand height by the apparatus of Example 2 and the measurement status of the compactability value by the conventional apparatus.

[Explanation of symbols]

 1 21 Kneading tank 4 24 Rotating wheel 7 27 Arm 9 Proximity sensor 10 33 Ultrasonic distance sensor 11 34 Water injector 12 35 Computer 13 36 Controller 28 Cylindrical body 29 Flat plate 30 Bar material 31 Sled plate 32 Wire rod

Claims (3)

[Claims] 1. A method for kneading and adjusting a molding sand in which casting sand containing bentonite is charged into a batch-type kneading tank, and a rotating wheel disposed in the kneading tank is revolved and rotated and water is added. Detecting the sand height in the kneading tank of the molding sand being adjusted, and controlling the amount of water added based on the correlation between the sand height of the molding sand and the compactability value. Kneading adjustment method. 2. A kneading adjusting device for molding sand, comprising a rotary wheel for revolving and rotating in a batch type kneading tank, and a water injector for injecting water into the kneading tank. A distance sensor that directly detects the sand height of the foundry sand is fixedly provided on the upper side, and the distance sensor is connected to a calculator electrically connected to the water injector, and thus the kneading detected by the distance sensor is performed. The kneading adjusting device for molding sand, which is configured to calculate a shortage water amount by receiving a sand height signal of the molding sand and to send a signal to a water injector to control the water injection amount. 3. A casting sand kneading adjusting device in which a rotating wheel for revolving and rotating and a water injector for pouring water into the kneading tank are provided in a batch type kneading tank. The tubular body is vertically oriented and fixed to a supporting arm that revolves together with the wheel, and the tubular body is fixed to the supporting arm.
A bar with a flat plate attached to its upper end is vertically movably inserted and arranged, and its lower end reaches the lower position of the tubular body at a position away from the tubular body mounting position in the support arm and slid upward. The upper position of the returning plate is rotatably supported up and down, the lower position of the sled plate and the lower end of the bar are connected by a wire rod, and the height position of the flat plate is above the orbit of the bar. A distance sensor for detection is fixedly provided, and the distance sensor is connected to an arithmetic unit electrically connected to the water injector, and the amount of water shortage is calculated by receiving a plate height signal detected by the distance sensor. A kneading adjustment device for molding sand is characterized in that a signal is sent to the water injection device to control the water injection amount.