Gas mixt. prepn. appts. - with controllable passage across piston in thick-walled glass cylinder moved by stepper motor

摘要

Apparatus for the preparation of a gas mixture with a precise composition has a cylinder with a PTFE piston and two piston rods on both sides. The piston is driven by stepper motor, moving a micrometer. A valve inside the piston controls the transfer of gas from one side of the piston to the other. Stirrers and temp./pressure sensors are also provided. - A thick-walled glass cylinder(1) has two face ends with grooves (2) for O-rings(3) to seal the end plates(4,5), using the tie rods(9). A PTFE piston(7) has twin O-rings(8,9) and a first piston rod(10) which passes through the cylinder in a stuffing box(11) with twin O-rings(12). A micrometer scale(90) is present. The handle(20) controls a valve(21). Stirrers(23),36) are magnetically driven by external magnets(24,24a). Another piston rod(25a) is attached to the piston top. A stepper motor(70) turns the brass nut(71) and moves the feedscrew(73).