Fluid flowmeter using differential pressure tube - has swinging shutter with curved attachments to achieve linear transfer characteristic

摘要

The fluid flowmeter operates on the differential pressure principle, the rate of flow being directly proportional to the pressure difference. The flowmeter tube is divided across its rectangular bore by a split screen (4)(4'), the upper and lower halves being separated by a narrow slit. the upper, longer part of the screen is attached to the upper wall of the tube (5) and is able to swing forwards and backwards thus varying the size of the slot opening. Attached to each side of the swinging plate are curved grids or wire mesh screens (7)(7') which form inherently-stable roll-off surfaces. These reduce the effective length of the plate during an increase in pressure and improve the stiffness of the plate. The pressure difference between both faces of the plate is transferred via vents connected to a differential pressure apparatus (6)(6').