JPH01278934A - Method and instrument for measuring compactibility value of molding sand - Google Patents

Abstract

PURPOSE:To automatically and repeatedly measure compactibility (CB) value by piling molding sand on the plane surface to spread it to almost uniform thickness, compressing with a pressurizing head and measuring compressive rate with this pressing to decide the CB value. CONSTITUTION:The molding sand and binder are kneaded with a kneading machine and poured with rather a little quantity of water. The kneaded molding sand A is charged in a lamination layer adjusting chute 15 and piled on a conveyor 20 and at the time of becoming the prescribed quantity or more, a sand level sensor 17 outputs full sand signal. The outlet of the kneading machine is closed and the conveyor 20 is shifted by the prescribed distance to the arrow mark direction and stopped. The molding sand A is regulated to the height of the upper face with a scraper part 16 and supported to the side parts thereof with both side faces 21, to spread under the constant piled height on the conveyor 20 and stop at the measuring position B. By descending the pressurizing head 26 with an air pressure cylinder 27, the molding sand A is compressed, and the difference of heights of the molding sand A before and after compressing is indicated as displacing rate in a displacement sensor 30 and outputted as the CB value changed into voltage signal. By this method, the molding sand is conveyed and the CB value of the molding sand can be automatically and repeatedly measured.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a molding sand compactability value measuring method and apparatus for measuring the compactability value of molding sand.

<Conventional technology> Generally, when molding sand is prepared as foundry sand suitable for mold making, an appropriate amount of water and a binder are added to the foundry sand and kneaded, and the compactability value (
Adjustments are made so that the CB value (hereinafter abbreviated as CB value) becomes a predetermined value.

Conventionally, the CB value of the foundry sand has been measured and managed by the intuition of skilled workers, making it difficult to accurately determine the CB value, and unattended measurement through automation has been impossible.

Therefore, a) a molding sand supply section equipped with a lump-breaking means, b) a test tube for filling with molding sand, C) a full empty detection means, d) a scraper, and e) a press for operating the pressure head. C of the casting sand without relying on the operator's intuition, using a device equipped with a machine, f) a measuring device that can measure the amount of compaction of the foundry sand.
A method of automatically measuring the B value has been proposed (see, for example, Japanese Patent Laid-Open No. 59-220245).

<Problems to be Solved by the Invention> However, in the method and apparatus for measuring the CB value of molding sand having such a conventional configuration, the test tube filled with molding sand is
Measurements are taken by moving back and forth between the molding sand supply section and the press, which complicates the equipment as there are many moving and sliding parts, and the operation of the equipment becomes unstable due to the presence of dust. However, there are problems in that it requires frequent maintenance and inspection, and the reliability of the measured values decreases.

In addition, due to the friction caused by the sand and its corrosive nature, molding sand gets stuck to the inside of the test tube over time, causing problems in the fit between the pressure head and the test tube, and making it impossible to perform measurements. This invention was developed in view of the problems of the prior art, and its purpose is to simplify the construction of the device, reduce the effort required for maintenance and inspection, and to accurately It is an object of the present invention to provide a method and apparatus for measuring the CB value of foundry sand that can automatically measure the CB value.

Means for Solving the Problems> The present invention has been made to achieve the above object, and the method of measuring the compactability value of molding sand according to the first invention comprises stacking the molding sand on a movable plane and measuring the thickness. Spread the molding sand so that it is approximately uniform, press the molding sand with a pressure head, measure the amount of compression of the molding sand due to the pressing,
Determine the compactability value.

A compactability value measuring device for molding sand according to a second aspect of the present invention includes a stacking thickness adjustment chute that is equipped with a scraper section and a sand level sensor and adjusts the deposited molding sand to a constant stacking thickness;
A moving means for transporting the foundry sand whose stacked thickness has been adjusted by the stacked thickness adjusting chute in one direction and moves it to the measurement position, and a pressure head are provided, and the foundry sand moved to the measurement position by the pressure head is provided. The pressure of the molding sand due to the pressure of the pressure means and the pressure head mentioned above! and measuring means for measuring one amount.

<Function> The function of the present invention is that foundry sand is first accumulated on the moving means by the stacking thickness adjusting chute. The accumulated foundry sand is adjusted to a constant stacking thickness by the scraper section by the operation of the moving means, and is spread out at the measurement position.

Then, the foundry sand is pressed and compressed by a pressure head at a measurement position, and the amount of compression is measured by a measuring means.
Determine the B value.

<Example> Hereinafter, the configuration of the present invention will be explained based on examples.

FIG. 1 is a front sectional view of a CB value measuring device according to an embodiment of the invention, and FIG. 2 is a side sectional view thereof. A stacking thickness adjusting chute 15 equipped with a sand level sensor 17, a conveyor 20 as a moving means constructed on the base 11, a pressing means 25 equipped with a pressure head 26, and a displacement sensor 30 as a measuring means. It is mainly composed of.

Is the stacking thickness adjustment chute 15 above the conveyor 20? A scraper section 16 is disposed on the f1 section, and on the downstream side of the lower opening of the stacking thickness adjustment chute 15, a scraper section 16 is formed in the shape of a gap with a predetermined distance from the upper surface of the conveyor 20.

In addition, at the predetermined height position of the stacking thickness adjustment shoe)-15,
A sand level sensor 17 is provided that detects moisture in the casting sand A to be thrown in and outputs a sand-full signal.

In the embodiment, the conveyor 20 is composed of an endless belt made of polyurethane resin with a core material of polyester fibers, and is driven by a drive source (not shown) to intermittently move a predetermined distance in the direction of the arrow in FIG. It is composed of

Furthermore, on both sides of the upper surface of the conveyor 20, a pair of side plates 21 extending in the direction of movement and having a predetermined height and facing each other are erected by the frame 14.

The pressing means 25 includes a pressure head 26 and a pneumatic cylinder 27 that drives the pressure head 26 in the vertical direction. This pneumatic cylinder 27 is fixed to a mounting plate 13 provided on the upper part of the frame 12 on the base ll,
A pressure head 26 is attached to the lower end of the rod,
It is arranged above the measurement position B on the conveyor 20. Further, on the lower surface of the conveyor 20 at the measurement position B, a pedestal 28 is provided that faces the lowered pressure head 26 via the molding sand A and the conveyor 20.

In the embodiment, the displacement sensor 30 is composed of a linear sliding type potentiometer, and is connected to the pressure head 26 by a connecting member 31, and is arranged to slide vertically in parallel with the pressure head 26. ing. The displacement sensor 30 is configured to output a voltage signal corresponding to the amount of displacement in conjunction with the pressure head 26.

The CB value measuring device 10 and the CB value automatic adjusting device configured as described above are installed as a measuring device. FIG. 3 is an overall configuration diagram showing the CB value automatic adjusting device equipped with the CB value measuring device 10. A hopper 1 for temporarily storing foundry sand, a kneader 2, a water injection nozzle 4 for injecting water into the kneader 2, and a kneader 2.
The apparatus is comprised of a CB value measuring device 10 connected to the discharge port 3 of the apparatus, and a control device 5 that controls the entire apparatus. The CB value measuring device 10, the sand level sensor 17, and the displacement sensor 30 are each connected to the control device 5, and the conveyor 20. The pneumatic cylinders 27 are connected to the control device 5 and are each configured to be driven and controlled.

The control device 5 of this CB value automatic adjustment device is equipped with a kneading machine control panel, a sequencer 1 calculation device, an AD converter, etc., and receives a full sand signal from a sand level sensor 17 and a voltage signal from a displacement sensor 30. At the same time, the conveyor 20
Intermittent operation, vertical drive of pneumatic cylinder 27, kneading machine 2
, the injection of molding sand A from the discharge port 3 into the stack thickness adjusting chute 15, and the injection of water from the water injection nozzle 4.

The operation of the CB value automatic adjustment device will be described below, focusing mainly on the operation of the CB value measuring device 10.

FIG. 4 is a flow chart of the control of the automatic CB value adjustment device. First, a predetermined amount of foundry sand and binder are poured into the kneading machine 2 from the hopper 1 and kneading is started. At this time,
There is no foundry sand A in the stacking thickness adjustment chute 15 of the CB value measuring device 10, the conveyor 20 is stopped, and the pressure head 26 is at the upper limit position.

Then, at the same time as the kneading starts, water injection nozzle 4 is turned on at time 11.
Initial water injection is performed in seconds. The time for this water injection is set so that the amount of water is slightly smaller than the target CB value.

Next, when the preset time of 12 seconds of kneading is completed, the discharge port 3 of the kneader 2 is opened, and the sand mixed with water is poured into the foundry sand A.
It is fed into the stacking thickness adjustment chute 15 as a liquid. At this time,
The foundry sand A is accumulated on the conveyor 20 in the stacking thickness adjusting chute 15, and when the amount thereof exceeds a predetermined amount, the sand level sensor 17 outputs a full-sand signal. When the full sand signal is output, the discharge port 3 of the kneader 2 is blocked, and the conveyor 2
0 operates, moves a predetermined distance in the direction of the arrow, and then stops.

Along with the operation of this conveyor 20, the stacking thickness adjustment chute 1
The foundry sand A located at the bottom of 5 moves in the direction of the arrow, and the accumulated foundry sand A gradually descends accordingly. The moving molding sand A has its upper surface height defined by the scraper part 16, is laterally supported by both side plates 21, and is spread out on the conveyor 20 in a constant stacked thickness, and is spread out at the measurement position B- 1, that is, it stops on the pedestal 28 and below the pressure head 26.

Subsequently, the pneumatic cylinder 2f operates to pressurize the pressurizing head 26.
lower. The pressure head 26 that has started to descend comes into contact with the molding sand A on the upper surface (corresponding to hi in FIG. 5) of the molding sand A spread on the conveyor 20, and the molding sand A is lowered by the pressure head at a constant pressure. 26. Immediately after the pressing, sand escape occurs in the foundry sand A as shown by the dotted line arrow in FIG. It stops at the compression height h2.

The amount of compression of this height hl-h2 is expressed as the amount of displacement of the displacement sensor 30, and the CB1 value of the foundry sand A converted into a voltage signal (
As a result, the control device 5
are the target CB value and CB.

By comparing the values, a water injection time of 13 seconds corresponding to the difference is calculated, and an additional water injection time of 13 seconds is performed to the next kneaded sand. Then, the pressure head 26 rises to the upper limit position, and when the additional water injection ends, the kneading machine 2 performs kneading for 14 seconds.

Next, according to the above process, the additional water injection and kneaded foundry sand A is transported to the measurement position B, and the CB2 value of the foundry sand A is measured (during this time, the previously measured foundry sand A is transferred to the conveyor 20), and if the CB2 value is the target CB value or a CB value close to it, the initial water injection time of 11 seconds for the next cycle is determined, and the conveyor 20 is operated. Then, one cycle of the automatic CB value adjustment device consisting of water injection, kneading, and CB value measurement is completed.

In this CB value measuring method and apparatus, the following experiment was conducted in order to improve the accuracy of the measured CB value.

That is, the diameter of the pressure head 26 and the stacked thickness h1 of the molding sand A are factors in the accuracy of the CB value. C while changing the pressurizing pressure P
In addition to measuring the B value, we also measured the CB value using a general-purpose rammer one-type method, and conducted an experiment to confirm the correlation between them. Pass the test tube through a mesh sieve (height 100
mll1. After filling the molding sand to a diameter of 50 m (111) and scraping off the excess sand, it was rammed three times with a rammer, and the amount of compression of the foundry sand at that time was divided by the original height of the sand and expressed as a percentage.

In this experiment, the stacking thickness h1 was 25 mm, 40 mm,
55IIll! 3f of l! 1. Diameter 40mm, 80
By setting two types of a+m and changing the pressurizing pressure P, the surface pressure applied to the pressurizing surface of the foundry sand A was changed, and the correlation results shown in Table 1 were obtained.

Table 1 (Evaluation criteria ◎: Excellent O: Good Δ: Acceptable ×: Unacceptable)
According to Table 1, a good correlation can be obtained if the surface pressure is 0.094Kg10n'' or more, and a practical correlation can be obtained if the stacking thickness h1 is 40mm or more (excluding at least 25cm or less). Ta.

FIG. 6 shows one of the above embodiments in which the pressurizing pressure P=0.
75Kg/cm', surface pressure += 0.188g/cm'
, stacking thickness h1 = 40 mm, diameter D = 40 arms, and shows a high correlation with the measured CB value using one type of rammer.

Note that the present invention is not limited to the above explanation and troubles, and the embodiments thereof can be changed without departing from the technical idea of the present invention. For example, even if the scraper section is formed separately from the stacking thickness adjusting chute, similar effects can be achieved.

Further, the moving means may be a turntable that rotates on a constant plane.

Furthermore, the planar shape of the pressure head can be other than circular.

<Effects of the Invention> As explained above, according to the present invention, the molding sand is transported by the moving means that operates in one direction, and the C of the molding sand is automatically reduced.
The B value can be measured repeatedly. Therefore, unlike conventional examples, there is no reciprocating mechanism, and a simple and compact device with fewer moving and sliding parts can be constructed, and the device is less unstable due to dusty environments. It is possible to avoid this occurrence, reduce the effort required for maintenance and inspection, and obtain high measurement reliability.

Furthermore, since the test tube shown in the conventional example is not used for measuring the CB value, there is no need to worry about failure to measure due to poor fitting with the pressure head.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view of a molding sand compactability value measuring device according to an embodiment of the present invention, FIG. 2 is a side sectional view thereof, and FIG.
The figure shows a CB equipped with this compactability measurement device.
Fig. 4 is a flowchart of the control of the automatic CB value adjustment device, Fig. 5 is an explanatory diagram showing the compression of molding sand by the pressure head, and Fig. 6 is the main measurement method. It is a graph showing the correlation between the measured value of the measuring means and the CB value measured by one type of rammer. 10... Compactability value measuring device, 15...
Stacking thickness adjustment chute, 16... Scraper part, 17... Acid level sensor, 20... Conveyor (8 moving means), 25... Pressing means, 26... Pressure head, 30... Displacement sensor (measuring means). Patent application Hitochuo Malleable Industry Co., Ltd. Figure 1 Figure 2

Claims (1)

[Claims] 1) Spread out molding sand so that the stacking thickness is approximately equal on a movable plane, press the molding sand with a pressure head, and compress the molding sand by the pressing force. A method for measuring the compactability value of foundry sand, the method comprising measuring the compactability value of foundry sand. 2) A stacking thickness adjusting chute that is equipped with a scraper section and a sand level sensor and adjusting the stacking thickness of the injected molding sand to a constant stacking thickness, and a stacking thickness adjusting chute that transports the molding sand whose stacking thickness is adjusted in one direction. a moving means for moving the molding sand to the measuring position; a pressing means for compressing the foundry sand moved to the measuring position by the pressurizing head; and a pressing means for measuring the amount of compression of the foundry sand by the pressure of the pressing head. A compactability value measuring device for foundry sand, comprising: a measuring means;