Pressurized fluid density balance

Abstract

A conventional fluid density balance beam measurement instrument used for measuring fluid density at atmospheric pressure is converted for use to measure fluid density at super-atmospheric pressure. The conversion is made without modifying the structure of the conventional instrument. A pressure lid, placed over the open mouth of the instrument's sample cup, is held in place by a removable retaining structure that wraps around the base of the cup. A screw ring at the top of the retainer applies a retaining pressure against the lid. Pressure is applied to the cup through a check valve stem extending through the lid. An adjustable flange on the rim of the lid permits the lid to advance into the cup to change the cup volume for sizing the cup to obtain a precisely known volume for measurement. A counterweight is removably connected to the balance beam to compensate for the weight added by the lid and retaining structure. A weight compartment in the counterweight permits the addition of small amounts of weight to calibrate the balance beam. The lid, retaining structure and counterweight are removable to return the instrument to its conventional configuration for normal atmospheric measurements.