JPS6092041A - Method for measuring amount of pulverous powder in molding sand - Google Patents

Abstract

PURPOSE:To measure continuously the amt. of pulverous powder in molding sand in short time by bringing a specified amt. of dry molding sand into collision against a baffle plate to generate dust, sucking the dusty air, conducting such air to a concn. detecting part and measuring the quantity of the light passed through said part. CONSTITUTION:The molding sand in a conveyor 19 is adequately sampled by a scraper 19a and is dried by the heater 21 of a sand drying conveyor 20, then the sand is drawn into a hopper 16. The sand fed into a dust generating device 1 by a rotary feeder 17 is blown upward in a blast tube 3 by a blower 2 so as to collide against a baffle plate 4, by which dust is generated. The dusty air is sucked by a suction blower 15. The quantity of the passed light of the air passing in a concn. detecting part 7 is measured with a light projector 10 and a photodetector 11 each consisting of a phototube. The measured quantity of the light is converted 12 and is inputted to a microcomputer 13 which determines the amt. of the pulverous powder from the average value thereof. The amt. of the pulverous powder in the molding sand is adequately known and the molding sand is regulated to optimum with said amt.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for measuring the amount of fine powder contained in foundry sand used in a foundry.

In general, if the viscosity content in the foundry sand is low, the strength of the mold will be reduced, and if the clay content is high, the air permeability will be reduced and the formation of lumps will increase. Therefore, it is important in a foundry to control the amount of fine powder such as clay in C foundry sand to a constant level.

Conventionally, the amount of fine powder (caking particles such as clay) contained in foundry sand has been measured by the following method.

In other words, the clay content in the foundry sand can be determined by washing a certain amount of the foundry sand with water to remove the clay content, and then washing the remaining sand grains with a dry cloth and measuring the weight of the sand grains. ing.

The conventional measurement method described above has the following drawbacks.

(1) It is not possible to measure the amount of fine powder continuously.

(2) It takes 1 hour to wash the foundry sand and 1 to 2 hours to dry it, for a total of 2 to 5 hours of measurement time.

For this reason, it has not been possible to continuously and uniformly control the amount of fine powder in the foundry sand.

The present invention aims to improve the drawbacks of the conventional methods for measuring the amount of fine powder, and to provide a method for measuring the amount of fine powder contained in foundry sand continuously and in a short period of time.

The present invention will be explained below based on examples. FIG. 1 shows an example of an apparatus for carrying out the present invention. In the figure, a dust generating device 1 has an inlet 1α at the bottom that takes in high-speed air from a pressure blower 2, and a plast tube 3 and a collision plate 4 are provided above the inlet 1α. Also, between the population 1a and the collision plate 4, there is an inclined plate 5 and a sand discharge plate 6 for circulating the foundry sand in the dust generator 1 and for discharging it to the outside.
is provided. The sand #r projecting plate 6ti can be opened and closed freely by the rotating part 6a.

A conduit 8 communicating with the concentration detection section 7 is provided at the upper part of the dust generating device 1 .

A set of transparent plates 9 are connected to the concentration detection section 7 via a space 7a.
A and 94 are attached, and the light from the phototube projector 10 is received by the phototube receiver 11 through the transparent plates 9a and 9k, where it is converted into an electrical signal and this signal is input to the microcomputer 13 through the A/D converter 12. It has become so. The lower end of the degree detection unit 7 is connected to a suction proar 15 via a conduit 14, and the suction proar 15 is further connected to a dust collector (not shown).

A conduit 18 is provided on the side wall of the dust generator 1 so that the foundry sand in the hopper 16 is fed into the dust generator 1 by a rotary feeder 17. Also, 19 is a molding sand transport conveyor, which is a conveyor for transporting return sand in the mold heritage line. f6ru. Conveyor 19 [IJ scraper 194 is provided, and a certain amount of foundry sand is transferred to
0. Sand drying conveyor 20
A drying device 21 such as an infrared heater is installed in the hopper 16, and dried foundry sand is supplied to the hopper 16. The foundry sand on the sand drying conveyor 20 is dried by the drying device 21 so that its moisture value becomes approximately O.

Next, the method for measuring the amount of fine powder according to the present invention will be explained.

A part of the foundry sand transported by the conveyor 19 is transferred to a sand drying conveyor 20, and while traveling on this conveyor 20, the foundry sand is dried by an infrared heater 21. Put the dry foundry sand into the hopper 16 and feed it to the rotary feeder 17.
A certain amount of the dust is sent into the dust generator 1 by the dust generator 1. In the dust generating device f&ic1, the molding sand is passed through the plastic tip 3 by the pressure feeder 21C and is applied to the Ils projecting plate 4 at the upper part of the dust generating device 1 at high speed. The fine powder in the #f material ltL and the fine powder adhering to the sand particles float in the air and generate dust.

This dust-generating air containing clay and the like is sent to the concentration detection section 7 through the conduit 8 by the suction proar 15. The dust air flowing into the concentration detecting section 7 is irradiated from a phototube projector 10 through a transparent plate 9a, and the light/darkness of the passing light is converted into an electrical signal by a phototube receiver 11, which is sent to a microcomputer through an A/D converter 12. Enter 13. The microcomputer 13 calculates the amount of fine powder in the foundry sand based on the calculation formula for calculating the amount of fine powder stored in advance. Note that the measurement data is input to the microcomputer 13 at intervals of, for example, 0.1 seconds, and each time the amount of fine powder is calculated, the average value of this amount of fine powder for one minute is calculated, and this value is added to the foundry sand. It is best to make it appear as a fine powder amount. Once passing through the detection section 7, the air containing dust is guided to the dust collector through the conduit 14.

In the dust generator 1, sand grains that collide with the collision plate 4 and fall fall onto the inclined plate 5, descend, and are discharged to the outside of the dust generator 1 through the sand discharge plate 6.

Note that by adjusting the inner degree of the sand discharge plate 60, the inclined plate 5
A part of the descending sand may be guided to the bottom of the dust generator 1 and circulated so as to collide with the collision plate again.

Furthermore, in the present invention, it is also possible to measure the amount of fine powder by short-time batch processing. That is, the dust generating device 1
With a certain amount of foundry sand being supplied to and the sand discharge plate 6 closed,
Molding sand is made to collide with the collision plate 4 for a certain period of time (for example, 3 minutes), the amount of fine powder is measured at certain time intervals, and the amount of fine powder for that batch is calculated from the average value of the measured values within this time period. Next, after opening the sand discharge plate 6 and discharging the sand grains to the outside, the sand discharge plate 6 is opened again.
Measure the fine powder concentration during the following time periods. In this way, the fine powder concentration can be measured by continuing short-term batch processing.

As explained above, the present invention is capable of measuring the amount of fine powder contained in foundry sand continuously in a short period of time, making it possible to create sand molds with optimal mold characteristics and producing cast products. can contribute to improving the quality of products.

[Brief explanation of drawings]

+i! r4r9IP+ There is also a drama with a 1ψ value. 1... Dust generating device 4... Collision plate 5... Inclined plate 6... Sand discharge plate 7... Concentration detection section 1o... Photocell floodlight 11 ・
...Phototube receiver 13 ...Micro combi coater 20 ...Sand drying conveyor.

Claims (1)

[Claims] A certain amount of dried foundry sand is sequentially collided with the collision plate to generate dust, and the dust-generating air is guided to the concentration detection section, the amount of light passing through this concentration detection section is measured, and the fine powder is determined from the original amount of passing through. A method for measuring the amount of fine powder in foundry sand, characterized by measuring the amount.