Evident LogoOlympus Logo
자료실
Application Notes
자료로 돌아가기

도자기의 고전압 절연체의 실리콘 코팅 측정


Application: Nondestructive measurement of the thickness of silicone coatings on porcelain high-voltage insulators.

Problem: Porcelain insulators are commonly used in high-voltage power transmission systems. Over time, a buildup of atmospheric contaminants such as salt spray or chemical dust can create a conductive path that causes a flashover. Silicone coatings such as Dow Corning's Sylgard® have been developed to prevent contaminant buildup. These coatings must be applied in some minimum thickness (typically 0.020 in. or 0.5 mm) to be effective. Because of the fairly high cost of the coating material, most users will want to apply no more than the minimum required thickness. Mechanical measurement of coating thickness is not possible without cutting into it. However, a properly set up ultrasonic gage can measure the coating thickness quickly and nondestructively.

Theory of Operation: High-frequency sound waves will reflect from boundaries between materials of differing acoustic impedance. (Acoustic impedance is a physical property defined as density multiplied by the speed of sound in the material). Because silicone coatings have an acoustic impedance much lower than ceramics, a pulse of sound energy will reflect back from a silicone/porcelain boundary. All ultrasonic thickness gaging is based on a precise measurement of the time interval that represents the transit time of an ultrasonic pulse through the test material. Usually this interval will be measured as a round-trip transit time that must be divided by two to obtain the one-way transit time. Ultrasonic gaging also requires knowledge of the speed of sound in the test material, which is normally determined with the aid of calibration standards. Using this known sound velocity and the measured sound transit time, the instrument computes material thickness using the simple formula:

Thickness = Velocity x One-Way Transit Time

The accuracy of measurement will be proportional to the accuracy with which the time interval is measured and the accuracy to which the sound velocity is known. For silicone coating measurements, accuracies of ± 5% can usually be achieved.

Equipment: The recommended instrument for silicone coating measurement is a specially set up Olympus Model 38DL PLUS or 45MG with Single Element software portable thickness gage with an M2055 handle-style 20 MHz delay line transducer. Measurements can be made over a thickness range of approximately 0.005 in. (0.12 mm) to greater than 0.050 in. (1.25 mm). Gage setups for measurement of silicone over porcelain are dedicated to this application and should not be used for other types of testing. 

Procedure: Using a properly set up gage, couple the transducer to the measurement point using firm and steady pressure. Normally, it will be necessary to use a drop of liquid couplant (glycerin, propylene glycol, oil, or water) between the transducer tip and the test surface to insure good coupling of sound energy. The gage will display the thickness of the silicone coating at the point of measurement. Gage calibration should be periodically verified using a reference standard consisting of a known thickness of silicone bonded to a ceramic base. For acoustic reasons it is essential that the reference standard exactly duplicate measurement conditions; unbonded silicone may not be used. We can supply further gage calibration information on request.

Olympus IMS

이 애플리케이션에 사용되는 제품

72DL PLUS™ 고급 초음파 두께 측정기는 사용이 간편한 휴대용 장치로 빠르고 정밀하게 두께를 측정합니다.최대 125MHz의 단일 요소 탐촉자와 호환되는 이 혁신적인 두께 측정 도구는 다층 도장, 코팅, 플라스틱과 같은 초박막 소재의 두께의 측정에 매우 적합합니다.최대 6층의 두께를 동시에 표시할 수 있습니다.

45MG 고급 초음파 두께 측정기에는 표준 측정 기능은 물론 다양한 소프트웨어 옵션이 있습니다.이 독특한 두께 측정 도구는 당사의 이중 요소 및 단일 요소 두께 측정 탐촉자와 호환됩니다.

다용도로 활용 가능한 38DL PLUS™ 측정기를 이중 요소 탐촉자와 함께 사용하면 부식된 파이프의 두께를 측정할 수 있으며, 단일 요소 탐촉자를 사용하면 박층 또는 다층 소재의 두께를 매우 정확하게 측정할 수 있습니다.

죄송합니다. 이 페이지는 해당 국가에서 사용할 수 없습니다.
아래 양식을 작성하여 원하는 내용을 알려주십시오.
죄송합니다. 이 페이지는 해당 국가에서 사용할 수 없습니다.