JPS574515A - Flowmeter for liquid - Google Patents

Abstract

PURPOSE:To enable the high-precise measurement of a quantity of flow even at a small quantity of flow range, by a method wherein detecting elements for the passage of a spherical element are placed at two locations at a main path of a close loop path, and a section ranging between the detecting elements forms a section where a movement speed is measured. CONSTITUTION:First and second detectors 23 and 24, which detect the passage of a spherical element 22, are installed at two locations of a close loop path 20, and the detectors 23 and 24 can consist of, for example, a photocoupler. The length of the path ranging between the detectors 23 and 24, which forms the measurement section for the line speed of said element 22, is set so as to be below 90% of the main path, and is set so that the flow can be measured at a range where the line speed of the element faithfully corresponds to the flow of a liquid in a rectifying state. This permits the high-precise measurement of the quantity of flow even at a small quantity of flow range through the drive of the element 22 in the close loop path 15 through the force of jet current from an orifice 34.