JPS58165038A - Moisture meter for molding sand - Google Patents

Abstract

PURPOSE:To make it possible to easily obtain a temp. range required in measuring moisture, by a method wherein the heating temp. of molding sand is measured by a radiation thermometer and the output of microwave is controlled by the obtained temp. signal to control said heating temp. CONSTITUTION:In measuring the moisture content of molding sand 6, a predetermined amount of molding sand 6 is at first placed on a receiving tray 13a in a heating oven 1 and zero point adjustment is carried out so as to adjust the measuring value of an electronic balance 13 to zero while the correction of a radiation ratio is simultaneously carried out corresponding to the component of molding sand. That is, the radiation ratio is set every material to be used, and by correcting a radiation thermometer 4 corresponding to said radiation ratio, a temp. range required in measuring moisture is obtained. In the next step, the heating of molding sand 6 is started by the irradiation of microwave to measure the reduction of moisture in molding sand 6, and when said sand reaches a constant wt., the stopping signal of microwave and purge air is issued from a constant wt. controller 16 while the measured value due to the electronic balance 13 is displayed by a display part 14 and simultaneously recorded by a printer 15.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a foundry sand moisture meter for measuring the moisture content of foundry sand used to mold microwave-hardened castings.

The molding sand used to make conventional microphone four-wave hardening molds contains carbides such as resin, starch, pitch, coal powder, etc., and iron powder, and when this molding sand is heated by irradiating microwaves, electrical appliances There were many cases where the mold would heat up and burn locally. For this reason, it is not possible to heat and dry while maintaining the temperature range of 105±5° C. generally used for moisture measurement, and it is extremely difficult to obtain the required measurement accuracy of around ±1 bullet. In order to solve this problem, there is a method of setting 1 moisture loss in terms of time, but this method has drawbacks such as the inability to obtain accurate measured values when the type and water content of the foundry sand are affected.

This invention was made with the aim of improving these drawbacks, and it is possible to measure the moisture content of molding sand with higher accuracy than foundry sand heated by four-wave microphone heating while maintaining the temperature range necessary for moisture measurement. The purpose of this invention is to provide a countermeasure to prevent carbides and the like from being reduced due to localized heating and combustion of foundry sand.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.
In the figure, reference numeral 1 denotes a microwave heating furnace, which is equipped with a waveguide 2 at the top for introducing microwaves, and a stirrer fan 3 for diffusing the microwaves introduced into the paper heating furnace I through the waveguide 2. There is. 4R A radiation thermometer (II degree range 50-1000℃, measurement wavelength 2-225m) installed in the center of the upper part of the heating furnace 1, has emissivity correction and signal modulation functions, is directed downward, and a metal tube 5 is provided below the radiation thermometer 4 so as to hang down within the heating furnace 1 .

The metal tube 5 is a molding sand 6 placed in the center of the bottom of the heating furnace 1.
A stainless steel pipe or the like whose inner diameter is less than 1/2 of the length λ of the microwave wave used in the heating furnace 1 is used. Ru. The above-mentioned sand 6 is sprayed onto the upper end of the metal tube 5 to determine the position of the measurement position. 114 f
Wal! ! ! L &;l[l m'll'A*jl'
! '5 fQK.

A purge air supply port 8 is provided to prevent the air from leaking.

A ring-shaped monitor lamp 7Vi is used as shown in FIG. 4, and the metal tubes 5 are made of 211F5a and 5A. It may be possible to reach 6.

On the other hand, the temperature of the foundry sand 6 measured by the radiation thermometer 4 is sent to the converter 10 as a temperature signal of DCO~ls,4.
The current-voltage is converted into the emu cross phase measuring device 11, corrected by a correction value set in advance in this measuring device 11, and then output to the microwave control section 12. The microwave control unit 12 controls on/off the output of the microwave so that the heating temperature of the foundry sand becomes a preset m injection, for example, 105±5°C.

Further, the molding sand 6 to be subjected to the temperature measurement is placed on the tray 1'3α of the electronic balance 13 provided at the bottom of the heating furnace I. The electronic balance 13 is placed in the heating furnace I →, 1:
The cut receiver consists of a plate 13g and a weight measuring section +3A installed outside the heating furnace 1, and the weight measured by the weight measuring section 13A is displayed as a weight and a percentage on the display section!4. The measurement signal is input to the constant temperature controller 16.When the amount of water in the foundry sand 6 reaches a constant value, the constant temperature controller 16 outputs a microwave stop signal to the microwave controller 12, and supplies microwave and purge air. At the same time, the weight and weight of the foundry sand 6 at that time are displayed on the display section 14, and the values are recorded on the printer 5. □ Therefore, the moisture content of the foundry sand 6 To measure the amount, first place a predetermined amount of foundry sand 6 on the tray 13α in the heating furnace 1, and then adjust the zero point so that the measured value of the electronic balance 13 becomes zero before supplying purge air. At the same time, the emissivity is corrected according to the components of the foundry sand.As a method of stopping the emissivity, first, the temperature of the water is measured with a thermocouple and a radiation thermometer 4.

The result is the 2nd v! As shown in J, emissivity g-'=+
,.

The measurement error is within ±1°C. Next, when new sand (zircon sand) was used as the foundry sand 6 and the emissivity e was changed from 1.0 to 0.92, the measurement error was within ±1° C. as shown in FIG. In this way, the emissivity zt- is set in advance for each material used, and the radiation thermometer is corrected according to this emissivity C. This is the temperature range required for moisture measurement according to JIS! 1M+05±5°C can now be obtained.

Next, heating of the foundry sand 6 is started by irradiating microwaves, and at the same time, a pannier is supplied to prevent water vapor from accumulating in the molding sand 6 during heating. The decrease in moisture in the 6'' is measured, and when a constant weight is reached □, a signal to stop the microwave and purge air is output from the constant weight controller 16, and the heating by the microwave and the supply of the 6'' air are stopped. -The measured value was measured by the electronic balance 13.
Displayed on 1'4 h winter and recorded on printer 15 at the same time on the right.

'Na゛o□#! Figure 4 shows the measurement results when molding sand 6 with a microwave weight of 50V was heated until it reached a constant weight of 20f. The measurement time can be significantly shortened compared to ~90 minutes.One piece in one song II is made of skin sand (drying method 3.4%),□
Curve ゛B is pressurized sand (dry * j, a attack), and track II
C indicates molding sand 6 in which recovered sand (drying method: 1.1%) is the main component.

As described in detail above, when heating foundry sand whose moisture content is to be measured using microwaves, this invention controls the heating temperature using a radiation thermometer and controls the microwave output based on the obtained concentration signal. By controlling the heating temperature of the sand, it was easy to obtain the temperature range of +05 ± 1°C required for moisture measurement, and the decrease in moisture in the foundry sand was measured with an electronic balance to reach a constant weight. Since the microwave heating is stopped in seconds by a signal, the required accuracy of 10.1% can be obtained by using an electronic balance with a minimum reading accuracy of 1 mf in the range of 5 to 100 f. Become.

In addition, since it can be measured in a shorter time than the conventional JIS measurement method, it is possible to efficiently measure the moisture content of sand. Since the amount of water inside can be accurately measured, the 1-carbide will not be locally heated and burned during microwave curing of molds made using measured foundry sand, and will be uniformly hardened. This makes it easier to obtain molds of good quality.

[Brief explanation of the drawing]

The drawings show one embodiment of this invention, the fIs1 diagram is an overall block diagram, 1 Figures 2 and 3 are diagrams showing the data necessary for emissivity correction, and Figure 4 shows the moisture measurement results. The diagram and FIG. 5 are explanatory diagrams showing another embodiment □. 1 is a microwave heating furnace, 4 is a radiation thermometer, 6 molding sand,
12 is a microwave control unit, 13 is an electronic balance, and I6 is a constant weight controller. Applicant Komatsu Manufacturing Co., Ltd. Agent Masaaki Yonehara: 艮□- 6. Tadashi Hamamoto Figure 1 Figure 2 %'j:nr: Yes; Row Tahin 1F-113 Figure ~ ζ 15ml Hand, continuation Written amendment (spontaneous) December 23, 1980 Kazuo Wakasugi, Commissioner of the Patent Office 1, Indication of the case Patent Application No. 1983-046344
. 2. Name of the invention Foundry Sand Moisture Meter 3. Relationship with the person making the amendment Patent applicant address 2-3-6 Akasaka, Minato-ku, Tokyo Name (123)
) Komatsu Ltd. Representative Ryo Kawai - □. 5. Date of amendment order Voluntary amendment 6. Subject of amendment 2 Contents of amendment (1) Specification attached to application 9, page 2 IR, line 6 [・
...±191] is corrected to "...±α1-". Also, in the 9th line of the same page, "...and the water content is..." is changed to "...
・And the amount of dielectric material is...” is corrected. (2) In the same specification, on page F, line 18, after "...moisture content", "not affected by the amount of charcoal or combustible material" is added. ``Measured...1 to 1a'' on the 19th line of the same page, ``It will be as follows.'' At 1f, the ``moisture content when mixed with sand can be accurately controlled.'' , kiru・” and amend it.

Claims (1)

[Claims] A radiation thermometer 4 measures the temperature of the molding sand 6 from infrared rays emitted from the molding sand 6 put into the microwave heating furnace 1, and the temperature of the molding sand 6 is determined in advance by the temperature signal from the radiation thermometer 4. a microwave control unit 12 that controls the microphone V-wave output so that the temperature range is within the specified temperature range; an electronic balance I3 that measures the weight of the foundry sand 6 introduced into the microwave heating furnace 1; A foundry sand moisture meter comprising a constant weight controller 16 which outputs a four-wave stop signal from the microphone when the measured value reaches a constant weight.