· Shut-off seal is made by lowering the PTFE shoulder into a specially formed glass seat
· Design is based on the Mariotte principle and assures the drop rate regardless of the liquid level
· Internal delivery scale is graduated to allow accurate resetting on successive runs
· Constructed of glass, PTFE, and CTFE
· 634630 series is steam jacketed; hose connections on jacket allow the introduction of steam to heat funnel contents
· Probe FKM o-ring is size 110
· Suitable for use under moderate vacuum
· Standard Taper 19/22 refill valve/stopper has a special bore to permit initial equilibration of the apparatus when it is used under vacuum
· Graduated and numbered both up and down
· Supplied with operating instructions
· Manufactured from 33 expansion, low extractable borosilicate glass conforming to USP Type I and ASTM E438, Type I, Class A requirements