摘要 |
Apparatus for and a method of fabricating a Coriolis flowmeter made primarily of plastic. The Coriolis flowmeter of the invention makes extensive use of plastic and injection molding. All embodiments (100, 200, 300, 400, 500, 600) have a dynamically active structure including at least one flow tube (101, 102, 201, 301, 401, 555, 601, 602) that is formed of plastic by the use of injection molding. Other embodiments include balance bar (202, 302, 402), plastic flanges (104, 412, 501, 609, 611) and/or a plastic case (103, 403), and/or plastic brace bars (110, 210, 310, 405, 520, 521), and/or plastic bobbins for pick offs (LPO, RPO) and a driver (D), and/or plastic mounting surfaces (435, 436, 437) on a balance bar or flow tube for mounting the plastic bobbins of the pick offs and a driver. The injection molding process used to fabricate subject Coriolis flowmeter include the steps forming a material flow path core (706) using a core mold (702), placing the formed material flow path core into a wrapper mold (900) having a cavity (928, 929) whose surfaces define the exterior surface of the plastic Coriolis flowmeter structure to be formed, injecting low temperature metal or soluble material into the cavity of the wrapper mold, removing the plastic Coriolis flowmeter structure from the wrapper mold, and removing the material flow path core from the plastic Coriolis flowmeter by melting the low temperature metal core or by dissolving the soluble material using hot water. |