MANUFACTURE OF MEASURING PIPE FOR MINUTE ELECTROMAGNETIC FLOWMETER

摘要

PURPOSE:To enable the passage of a fluid to be measured to be formed with a high dimensional accuracy and a smooth inner wall surface by coating the surface by a lining material made from a thermoplastic resin and applying a machining or the like to the surface. CONSTITUTION:A pipe member 11 with flanges on both ends is provided with a stepped portion 13 formed on the central portion of an inner wall 11a in the axial direction of the member 11. An insulative lining material 14 is made from a thermoplastic resin material and provided on the inner wall 11a and end surfaces 12a. The inner wall 14a of the lining material 14 is formed with a smooth surface and a projected portion 16 is formed in the position corresponding to the stepped portion 13. The inner wall 11a and the end surfaces 12a are coated with the lining material 14 of the thermoplastic resin. Then, after the pipe member 11 is machined to be formed with a passage 17 having both end openings with diameters larger than that of the central portion, a forming trowel that conforms to a predetermined passage and heated to about 420 deg.C is inserted in the passage 17 from one side opening to form this one side opening of the passage 15 of a fluid to be measured. The other side opening of the passage 15 is processed in the same manner.