Sensitivity and versatility are increased over other models, and mercury requirement is reduced to 20–30 mL

The “Cartesian Diver” float drops away from the pump-out orifice on increasing system pressure and reseals it when the reference pressure set within the large bulb is re-attained. The reference pressure is easily set.

By means of the spherical joint, the attitude of the orifice can be adjusted to accommodate a small continuous leak (i.e. inert gas) without hunting of the float. Flash flushing is easily accomplished by changing the stopcock setting. Mercury not supplied. For clamp, see 89060-234.

A control point within 1 mm Hg. can be fine-tuned by adjusting the height of the pump-out tubulation.