Release Time:2019-03-09  Hits:

Indexed by: Journal Article

Date of Publication: 2011-11-01

Journal: INSTRUMENTATION SCIENCE & TECHNOLOGY

Included Journals: Scopus、EI、SCIE

Volume: 39

Issue: 6

Page Number: 495-509

ISSN: 1073-9149

Key Words: fluid power; steady flow; stepping motor; unsaturated soils; water pressure

Abstract: This study is concerned with the development of a novel, high-precision, steady-flow instrument applicable to common unsaturated soils such as clay, silt, sand, gravel soil, and soft soil. The instrument consists of three parts: a high-precision water pressure control system, a high-precision air pressure control system, and a high-precision measurement system. A stepping motor was chosen as the source of water pressure power because it had a high divided driver, reliable operation, simple structure, low cost, and easy maintenance. An electro-pneumatic pressure regulator was used to produce the demanded air pressure. High-precision measurement was archived by a high-resolution grating interferometer, a high-precision balance, and a high-speed 16-bit A/D converter. The device can fully meet the precision requirement of the water pressure, air pressure, and the measurement during the steady flow test for unsaturated soils, which is a very automatic instrument (automatic testing and recording). In this study, volumes of inlet water and outlet water, which are usually difficult to gauge in traditional modes, were gauged by a high-resolution grating interferometer (0.001 mm) and a high-precision balance (0.001 g), and the related experimental study was successfully accomplished.