JP2523213Y2 - Automatic measuring device for air permeability of foundry sand - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for automatically measuring the permeability of foundry sand.

[0002]

2. Description of the Related Art Conventionally, as an apparatus for automatically measuring the air permeability of foundry sand, for example, FIG. 3 is known. In this apparatus, reference numeral 50 denotes a sample cylinder holding a sand sample 104 therein, and the lower end opening side of the cylinder 50 is sealed by a lower plunger 130 and an O-ring 144. In the above apparatus, the precision blower 146 is connected to the orifice 148 through the air passage 150, and the orifice 148 is connected to the sample cylinder below the compacted sand sample 104 through the hole 160 and the air passage 162 of the lower plunger 130. It is connected within the body 50. In addition, the blower 146
The orifice 148 is connected to the air permeability meter 152 via an air line 154 closed by a valve device 156, and the side of the orifice 148 farther from the blower 146 is also connected to the meter 152 via an air line 158. Further, the meter 152 is electrically connected to the recorder 32 via a pressure-electrical converter 164. When the air permeability of the foundry sand is measured by the above-described apparatus, the pressure air precisely adjusted by the blower 146 is sent to the orifice 148, and the pressure drop across the orifice 148 is measured by the air permeability of the compacted sand sample 104. Is displayed on the air permeability meter as the value of. At the same time, the pressure electric transducer 1
An electric signal proportional to the air permeability of the sand sample 104 is sent to the recorder 32 via 64 to perform permanent recording.

[0003]

In the above-described method of measuring the air permeability, the air pressure measured by the orifice 148 is converted into the air permeability based on a previously determined curve of the relationship between the air permeability and the water column pressure. However, the sand sample used for obtaining the relationship curve is prepared based on predetermined blending conditions and processing conditions, and is different from the sand sample for which the air permeability is actually measured. Therefore, the air permeability obtained by the above measurement method was an approximate value and could not be said to be an accurate value. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an apparatus capable of automatically and accurately measuring the air permeability of molding sand.

[0004]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention has as its gist that the apparatus is constituted by the latest instruments and a computer. That is, according to the present invention, a blow head that can be air-tightly connected to one end opening of a test tube holding a test piece therein, one end communicates with the inner space of the blow head, and the other end communicates with a compressed air supply source. A first conduit which is provided in the middle of the first conduit, pressure control means for maintaining the pressure of the compressed air flowing through the first conduit at a predetermined pressure, and a first conduit downstream of the pressure control means in the first conduit. A flow rate sensor for detecting a flow rate of compressed air flowing through the first conduit per unit time; a first pressure sensor for detecting an air pressure in the inner space of the blow head; a flow rate sensor and a first pressure sensor A calculating means for calculating the air permeability of the test piece based on the compressed air amount and the air pressure detected by the method, and an output means for displaying a result calculated by the calculating means.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on an embodiment. FIG. 1 is an overall configuration diagram of the air permeability measuring device according to the present invention. In the figure, reference numeral 1 denotes a test tube, in which a casting sand test piece 2 compacted by a compacting machine with a test piece (not shown) is held. Reference numeral 3 denotes a blow head for blowing compressed air into the test tube 1, and the lower end of the test tube 1 is removably inserted into the air outlet. The contact portion between the two is made airtight by an O-ring 4. Reference numeral 5 denotes an air diffusion plate attached to an air outlet of the blow head 3. The inner space of the blow head 3 communicates with a compressed air supply source 7 such as an air pump via a first conduit 6 and communicates with a first pressure sensor 9 via a second conduit 8. . Then, a predetermined value (300 ml / s) is supplied from the compressed air supply source 7.
ec) The compressed air is supplied at the above flow rate. In the middle of the first conduit 6, an electropneumatic proportional valve 11 and a flow sensor 12 are provided in this order from the upstream side. The first conduit 6 includes an electropneumatic proportional valve 11 and a flow sensor 1
2 is connected to a second pressure sensor 14 via a branch pipe 13, and the second pressure sensor 14 is electrically connected to the electropneumatic proportional valve 11 via a pressure-electric converter 15. ing. Then, the second pressure sensor 14 detects the pressure fluctuation of the air flowing through the pipeline, and based on this, the opening / closing degree of the electropneumatic proportional valve 11 is adjusted, and the pressure of the air flowing to the downstream flow sensor 12 becomes a predetermined value (water column). (10 ± 0.05 cm). The first pressure sensor 9 and the flow sensor 12 are:
Each of them is electrically connected to the calculating means 16, and the calculating means 16 calculates the air permeability based on the measured values detected by the two sensors 9 and 12 by the air permeability calculating formula stored therein. I do. The result calculated in this way is displayed by the output means 17 electrically connected to the calculating means 16.

[0006]

In order to measure the air permeability of the foundry sand using the above-mentioned apparatus, the compressed air adjusted to a predetermined flow rate and a predetermined pressure is blown through the compressed air supply source 7 and the first conduit 6. Supply to head 3. The compressed air is blow head 3
Flows into the test tube 1 through the upper opening of the sample, and is released to the atmosphere after passing through the test piece 2. At this time, the air pressure in the blow head 3 is detected by the first pressure sensor 9 and is in the form of an electric signal. It is transmitted to the calculating means 16. Further, the amount of air supplied to the blow head 3 per unit time is detected by the flow sensor 2 and transmitted to the calculating means 16 in the form of an electric signal. The calculating means 16 calculates the air permeability by substituting these data into the equation of the air permeability stored therein, and transmits the calculated air permeability to the output means 17 in the form of an electric signal. Then, the output means 17 displays the air permeability in the form of a meter, recording paper, or the like.

[0007]

As is apparent from the above description, the present invention measures the air pressure in the blow head for supplying compressed air into the test tube and the amount of air per unit time supplied to the blow head. The air permeability is calculated by substituting both measured values into the equation for the air permeability. That is, the air permeability obtained by the present invention is a value of the sand sample itself in the test tube, and an accurate value can be obtained. In addition, since the present invention causes the instrument and the computer to perform all of the measurement, calculation and display, the measured value is free from cumbersome measurement and calculation work.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an air permeability measuring device according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Test cylinder 2 Test piece 3 Blow head 6 First conduit 7 Compressed air supply source 9 First pressure sensor 11, 13, 14, 15 Pressure control means 12 Flow sensor 16 Calculation means 17 Output means

Claims (1)

(57) [Scope of request for utility model registration] 1. A blow head 3 airtightly connectable to one end opening of a test tube 1 holding a test piece 2 therein, one end communicating with the inner space of the blow head 3, and the other end being compressed air. A first conduit 6 communicating with a supply source 7;
Pressure control means 11, 13, 14, 1 that are provided in the middle of the first pipe 6 and maintain the pressure of the compressed air flowing through the first conduit 6 at a predetermined pressure.
5, the pressure control means 11 in the first conduit 6,
13, 14, 15 provided downstream of the first conduit 6
The flow sensor 12 detects the flow rate of the compressed air flowing through the inside of the blow head 3 per unit time, the first pressure sensor 9 detects the air pressure inside the blow head 3, and the flow sensor 12 and the first pressure sensor 9 detect the flow rate. Molding sand, comprising: calculating means 16 for calculating the air permeability of the test piece 2 based on the compressed air amount and the air pressure; and output means 17 for displaying a result calculated by the calculating means 16. Automatic measuring device for air permeability.