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Volume 4, Issue 1
Displaying 1-5 of 5 articles from this issue
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Haruo TATENO1961 Volume 4 Issue 1 Pages 7-12
Published: January 20, 1961
Released on J-STAGE: September 29, 2009
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Kazuo SATOH1961 Volume 4 Issue 1 Pages 13-19
Published: January 20, 1961
Released on J-STAGE: September 29, 2009
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Yoshiaki UEMURA, Jun KOKAME1961 Volume 4 Issue 1 Pages 20-29
Published: January 20, 1961
Released on J-STAGE: September 29, 2009
JOURNAL FREE ACCESSThe method of air-test for leak detection was studied in an idealized model using glass capillarys submerged in ethyl-alcohol, water, and water solution of soap respectively.
With various inlet-pressure (P1), we measured the total volume (Q) and the number (N) of rising bubbles to the surface of the liquid from the tip of a capillary in unit time. The relation between Q and P1 was found to be expressed empirically like a viscous flow, Q=α (P12-12), where α gives an intrinsic constant for each leak and α for the air was proved to be equal to the value for the leakage from atmosphere to vacuum assuming the leakage was pure viscous flow.
In order that Q is independent on the kind of liquid, the range of α sets limit to the lowest value of P1. At the pressure P1 over 3.5 kg cm-2, α indicated a sensitivity of detectable leakage in this method was experienced to be about 4×10-7 mmHg ·l·sec-1 which was one hundredth of estimated value in other reference. The value of N in soap solution was found to be (2-3) times it in water, and that in alcohol to be (3-8) times it in water at the pressure was higher than a certain limited one.
However, in order to obtaine stablely this highest sensitivity by this method, we had to take care of the following points.
1), Before the system was submerged into the liquid, the compressed air was charged in the system up to the testing pressure which has been determined to be the highest value of allowed charging pressure.
2), The gas used to the test was also dissolved in the liquid up to saturation fully.
In an industrial field, the air test would be used to perform smoothly leak detection with a crystal water solution of the soap.View full abstractDownload PDF (1905K) -
Yoshaki UEMURA, Hirokazu FUZITA1961 Volume 4 Issue 1 Pages 30-38
Published: January 20, 1961
Released on J-STAGE: January 28, 2010
JOURNAL FREE ACCESSThe substitute sensitivity factor (φ) for the single ionization gauge method was obtained experimentally for propane and helium gas which had been used for the leak hunting at the laboratory with three fixed leaks and an oil diffusion pump system.
A series of fixed leak was made by flattening an annealed copper tube with inner diameter of about 1 mm and a flattened length of all the leaks was in 14 mm. The flow rates of those leaks were stably 3.0×10-3, 2.1×10-4, and 1.3×10-5 mm.Hg·1·sec-1 for air from an atmosphere to vacuum respectively.
When a probe gas was covering over the leak or removing from it, transitional changes of an ionization gauge, which electron currents was controlled automatically at a constant value by electric circuit, were recorded on an electrical self-recorder.
As to the φ values of the probe gases on three fixed leaks fixed values were not obtained just as the reference showed for other gases, but these values spreaded in a wide range as follows :
Probe gas leak rates of fixed leaks for air in mm Hg·l·sec-13.0×10-3 2.1×10-4 1.3×10-5
Propane 2613.8 13.64.8 6.83.3
Helium - (0.960.92) - (0.930.89) - (0.880.85)
In order to anaiyze these experimental data, flow rates of the gases were directly measured by the constant pressure method having a small dead volume. The characteristics of flow ratio to air are given as changing from viscous flow to molecular one as the leak rate of air becomes smaller.
The spread of φ is thought to be due to the fact that the pumping speed of oil diffusion pump system is unstable at transitional pressure rather than the ionization cross section of probe gases to electrons varies in the gauge.View full abstractDownload PDF (1563K) -
[in Japanese]1961 Volume 4 Issue 1 Pages 39
Published: January 20, 1961
Released on J-STAGE: September 29, 2009
JOURNAL FREE ACCESSDownload PDF (367K)
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