JPH1183775A - Method and apparatus for measuring containing trace amount of moisture of glass fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure a trace amount of moisture real time by a simple means without destroying glass fiber, by storing charge in a capacitor at a high voltage and energizing a sample sandwiched between electrodes with the charge. SOLUTION: A switch 2 is closed, a switch 3 is opened, and a capacitor 4 is sufficiently charged at a high voltage by a power source 1. Then, when the switch 2 is opened and the switch 3 is closed, the charge stored in the capacitor 4 is conducted through glass fiber sample 5 sandwiched between electrodes 6. And, a low voltage divided by a resistor 7 connected in series with the sample 5 is measured by a digital storage oscilloscope of a current measuring apparatus 8. A water content amount of the sample 5 can be estimated from an amplitude of the voltage. That is, the water content amount of the sample 5 is calculated by corresponding the voltage to a working curve of a previously formed voltage and the water content amount. Thus, the sample 5 can be held at a predetermined thickness, and measured data with high reliability is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a method for measuring a trace amount of moisture contained in glass fibers used in glass fiber processed products such as a heat insulating sound absorbing material, a filter medium for an air filter, a separator for a lead storage battery and a glass mat. And a measuring device.

[0002]

2. Description of the Related Art It has been empirically known that the water content of glass fibers for producing glass mats used for lead storage batteries greatly affects the quality of glass mats. However, the optimal amount of water for the quality of the glass mat is very small, about 0.2% or less by weight. Therefore, in order to measure accurately, appropriate means other than absolute drying of the glass fiber are required. Therefore, it takes time to obtain the measurement result, and it is difficult to control and manage the manufacturing process in real time. In addition, the weight of the sample also increased, and the sample used for measurement could not be used as a raw material thereafter because of absolute drying.

[0003] Under these circumstances, from the viewpoint of controlling and controlling the production process in real time, moisture meters used for grains such as rice and wheat, such as a DC resistance type, a capacitance type, a high frequency resistance type, and a micrometer. The applicability of the wave method, infrared method, etc. to the measurement of trace moisture contained in glass fibers was examined.

[0004]

However, none of the above moisture analyzers can measure a trace amount of water of 3% or less. The present invention has been made in view of such circumstances,
An object of the present invention is to provide a measuring method and a measuring device capable of measuring a trace amount of water in a simple manner and in real time without breaking glass fibers.

[0005]

That is, according to the method of the present invention for measuring a trace amount of water contained in glass fiber, a charge is accumulated at a high voltage in a capacitor, the charge is applied to a sample sandwiched between electrodes, and the electrode is charged. A resistor is connected in series, and a small voltage divided by the resistor is measured, and the voltage is calculated by associating the voltage with a calibration curve of a voltage and a water content prepared in advance. It is characterized by the following.

Further, according to the apparatus for measuring a trace amount of water contained in a glass fiber of the present invention, an electrode for holding a bundle of samples for measuring water, an insulating holding plate for holding the electrodes, and a sample for holding the sample at a constant pressure are provided. A measuring electrode portion configured by a pressurizing device, a charging circuit in which a power supply and a switch are connected in series between both electrodes of a capacitor for supplying a fixed amount of electric charge to the measuring electrode portion, and the switch, A switch that operates in reverse and an electrode and a resistor sandwiching the sample are connected in series,
Further, an electric measuring unit comprising an energizing circuit configured by connecting a current measuring device to the resistor in parallel is further provided.

According to the present invention, the structure having the above-described features can maintain a constant thickness without breaking the sample, and can obtain highly reliable measurement data.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram showing one embodiment of the present invention, and FIG.
Is a typical voltage waveform diagram of the digital oscilloscope obtained by the present invention, FIG. 3 is a calibration diagram of the current value and the water content of the present invention, FIG. 4 is an explanatory view showing a measurement mode of the present invention, and FIG. It is explanatory drawing of the measuring electrode part of the measuring device of this invention. FIG.
In the figure, reference numeral 1 denotes a power supply, and 2 denotes a switch provided between the power supply 1 and a capacitor 4 connected thereto, and these form a charging circuit for the capacitor 4. Further, the capacitor 4
, The electrodes 6, 6, the sample 5 and the resistor 7 sandwiched between the electrodes 6, 6 are connected in series via a switch 3 that is turned on and off in reverse to the switch 2. An electrical measuring unit A was configured by connecting a current-carrying circuit in which a current measuring device 8 having an oscilloscope was connected in parallel to the resistor 7. In FIG. 5 showing the measurement electrode portion B, 10
Is a pressing device having a fixture 10a for fixing the holding plate 11 of the electrode 6 and a spacing holder 10b, 12 is an adjusting plate interposed between the electrode 6 and the holding plate 11, and 13 is an electrode 6 and a measuring device. 9 is a shielded cable. In addition, as the material of the electrode 6 in the present invention, copper, iron, aluminum, brass, gold, platinum or the like is used, and the holding plate 11 for holding the electrode 6 is made of plastic, wood, glass having good insulating properties. And other materials are used.

In FIG. 1, first, a switch 2 is turned on,
The switch 3 is turned off, and the power supply 1 sufficiently charges the capacitor 4 having a capacity of about 400 μF with a high voltage (about 7500 V). Then, when the switch 2 is turned off and the switch 3 is turned on, the electric charge charged in the capacitor 4 flows through the energizing circuit and is energized (neutralized) through the sample 5 made of glass fiber sandwiched between the electrodes 6, 6. At this time,
The current value I of the circuit is expressed by the following equation (1) according to Ohm's law, where Rx is the resistance value of the sample 5 and Vc is the voltage across the charged capacitor 4. I = Vc / Rx (1)

The current I is the voltage Vc across the capacitor 4 (Vc = Q / C, where C is the capacitance of the capacitor,
Q varies depending on the amount of charge), but the charge is instantaneously neutralized by energization. However, since such a high voltage and a voltage that changes at a high speed cannot be directly measured, in the present invention, for example, a resistor 7 (relatively small resistance value r, r << Rx) connected in series to the sample 5 is used. ), And a small voltage Vt at both ends is measured by the digital storage oscilloscope of the current measuring device 8.

Since the current I is directly proportional to the voltage Vt, the amount of moisture in the glass fiber sample 5 can be estimated from the magnitude of the voltage Vt. The resistance value r of the resistor 7
Since the current I flowing greatly varies depending on the amount of water in the sample 5 made of glass fiber, the one appropriately changed from several tens Ω to several hundred Ω is used.

However, the resistance Rx of the glass fiber sample in the above equation (1) is the sum of the resistance of the trace water itself in the glass fiber and the contact resistance when the sample is sandwiched between electrodes. In order to keep the constant, it is desirable to make the pressure at the time of sandwiching constant, to make the surface state of the copper electrode plate and the glass fiber constant, and to make the thickness of the glass fiber to be measured constant.

On the other hand, the water content of the glass fiber shown in FIG.
Is obtained by measuring the weight immediately after the measurement of the energizing voltage, and determining the weight difference when the electrodes sandwiching the sample measured by the above method are completely dried with a dryer. That is, as shown, the current value and the water content have a direct proportional relationship.
At this time, in order to avoid non-uniformity of the water distribution, the area of the electrode is preferably 0.015 m ² or more.

[0014]

Next, examples of the present invention will be described. 4 and 5
In the explanatory diagram shown in FIG. 5, 19 μm diameter glass long fibers used for a glass mat for a lead battery are immediately after spinning and dried and dried.
Cured glass thread (thickness 10mm, single weight 6300g / m
² ) was measured as a sample 5 with a measuring device. The measuring electrode section B of this measuring apparatus has an electrode area of 100 mm × 15.
It comprises a plastic holding plate 11 having good insulating properties and holding a 0 mm copper plate electrode 6, and a pressing device 10 for sandwiching a glass thread as a sample 5 between the copper plate electrodes 6 at a constant pressure. Specifically, the pressurizing device 10 fixes the two holding plates 11 with the aligning fixture 10a via the spacing holder 10b, and makes the copper plate electrodes 6, 6 contact the sample 5 in parallel. Then, an adjustment plate 12 is interposed in at least one of the electrodes 6. Next, the switch 2 of the electrical measuring unit A composed of the circuit shown in FIG. 1 is turned on and the switch 3 is turned off, and a high voltage is applied from the power supply 1 to the capacitor 4 to accumulate electric charges. West,
On the other hand, the switch 3 was turned on, a fixed amount of electric charge accumulated in the capacitor 4 was passed between the copper plate electrodes 6 and 6 through the shield cable 13, and the current was measured by the current measuring device 8.

FIG. 2 shows an example of the voltage waveform recorded on the digital oscilloscope of the current measuring device 8 only at the moment when the power is supplied by the above method (at the moment when the electrode is sandwiched). When the relationship between the current value I calculated from these voltage waveforms and the weight percentage of water relative to the weight of the glass fiber was determined, a calibration curve having a linear relationship as shown in FIG. 3 was obtained.

For example, a voltage Vc = 7500 V is stored in a capacitor 400 μF, and the glass thread sample 5 is stored for 500 ms.
Charged. At this time, assuming that the value r of the resistor 7 in series with the sample 5 is 100 kΩ, the voltage V applied to the sample 5
If t is 1.2 V, the current value is 12 μm according to the above equation (1).
A was measured, and 0.1% of water could be calculated from the calibration curve of FIG.

As described above, according to the method of the present invention, it is possible to determine the superiority / disadvantage of a filamentous state immediately after spinning in a state of a large amount of water and the superiority of a filamentous state for a drying and curing development process. For this reason, if it does not fall within the set value, for example, if the water content is too high, dry enough to reduce it to the set value, and if the water content is too low, the filamentous drying in the subsequent process can be performed in a short time. The amount of moisture can be controlled and managed by performing operations such as pressing.

When the water content of the glass fiber exceeds a certain limit, it becomes almost conductive and the above-mentioned linear relationship is not established. Therefore, the water content of 1.2% or less is desirable.

In the above embodiment, the measurement of the trace amount of water contained in the glass fiber has been described. However, the present invention can perform the same measurement on other inorganic fibers, organic fibers, cloth, paper and the like. Of course, it is. Also,
The electric charge to be energized is a high voltage of 3500 V or more and the energization time is preferably about 500 ms.

[0020]

As described above, according to the present invention, the electric charge charged in the capacitor is determined based on the current value obtained when a sample containing a small amount of moisture of 1.2% or less is supplied for a short time. The extremely simple means and device of measuring the amount makes it possible to measure accurately in real time without destroying the sample, and heat insulating sound absorbing material, filter material for air filter, separator for lead-acid battery and glass fiber such as glass mat It is extremely effective for measuring the moisture content of glass fibers containing trace moisture used in processed products.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing one embodiment of the present invention.

FIG. 2 is a typical voltage waveform diagram of a digital oscilloscope obtained according to the present invention.

FIG. 3 is a calibration diagram of a current value and moisture according to the present invention.

FIG. 4 is an explanatory view showing a measurement mode according to the present invention.

FIG. 5 is an explanatory view of a measurement electrode section of the measurement device of the present invention.

[Explanation of symbols]

 Reference Signs List A Electrical measurement unit B Measurement electrode unit 1 Power supply 2 Switch 3 Switch 4 Capacitor 5 Sample 6 Electrode 7 Resistor 8 Current measurement device 10 Pressurizing device 10a Fixture 10b Spacing holder 11 Holding plate 12 Adjusting plate 13 Shield cable

Claims (2)

[Claims] An electric charge is stored in a capacitor at a high voltage, the electric charge is supplied to a sample sandwiched between electrodes, a resistor is connected in series to the electrode, and a small voltage divided by the resistor is measured. And measuring the amount of water in the glass fiber by calculating the amount of water in the sample by associating the voltage with a calibration curve of the voltage and the amount of water prepared in advance. 2. An electrode for sandwiching a bundle of samples for measuring moisture, an insulating holding plate for holding the electrodes, and a measuring electrode section comprising a pressing device for sandwiching the sample at a constant pressure; A charging circuit in which a power supply and a switch are connected in series between both electrodes of a capacitor for supplying a fixed amount of electric charge to the electrode section, a switch that operates in reverse to the switch, an electrode and a resistor that sandwich the sample; Are connected in series,
And a current measuring circuit comprising a current measuring device connected in parallel to the resistor, and an electrical measuring section comprising a current measuring device.