JPS6457123A - Measuring tube - Google Patents

Abstract

PURPOSE:To make it possible to measure the flow rate of a high pressure fluid and to measure electric conductivity, by arranging a nonmetallic tube having electrodes and a fluid pressure transfer part in a metallic pressure resisting outer tube in series, and sealing a pressure transfer medium in a space between the outer tube and the inner tube. CONSTITUTION:A pressure resisting outer tube 1 is a metal tube. Protruding parts 1b are formed at specified two places on the inner surface of the tube 1. A plurality of pressure transfer paths, which penetrate the tube in the axial direction of the pipe, are formed at each protruding part. A nonmetallic inner tube 2 is held with the protruding parts 1b so that a gap 16 is provided between the inner wall of the outer tube and the inner tube in a concentric pattern in the outer tube 1. A pair of electrodes 6 are provided at the tube wall at the center in an axially symmetric pattern of the tube. Irregular bellows 11 are fluid pressure transfer parts 3, which are bonded to the outer tube 1 and the inner tube 2 so that a gap 17 is formed between the out inner wall of the outer tube and the parts 3. A pressure transfer medium 12 is sealed in the gaps 16 and 17 and the pressure transfer paths. In such a structure, sufficient mechanical strength can be readily provided in the outer tube. Tensile stress in the circumferential direction is not applied to the nonmetallic inner tube 2. Therefore, the inner diameter of the tube is not changed. The interval between the electrodes is not changed. Thus, measuring accuracy can be maintained.