Variable area flowmeter

Claim 1

A rotameter comprising: A. a transparent plastic bar having flat front and rear faces and a generally rectangular cross-section encapsulating a thin-walled variable-area borosilicate glass tube having a precision molded longitudinally-extending variable-area passage therein containing a float, said bar having a lateral bore at the lower end portion thereof communicating through a duct with the inlet of the tube and having a lateral bore at the upper end portion thereof communicating through a duct with the outlet of the tube, B. a channel-shaped frame member adapted to receive said bar and having a wall which abuts the rear face of said bar, the front face of the bar being exposed and having indicia inscribed thereon, said wall having holes therein in registration with said lateral bores, and C. hollow retaining elements extending through said bores into said holes to engage inlet and outlet pipe couplers socketed in the holes in said wall, said retainer elements having openings therein communicating with said ducts whereby fluid admitted into said inlet coupler passes through said tube passage into said outlet coupler, one of said retainer elements being a control valve.