Abstract: A portable inexpensive manometer is realized by forming a housing assembly of two pivotable panels. The probe and a major portion of the tube are stored within the interior of the housing until the manometer is to be used. The measuring liquid is stored in a reservoir which is mounted adjacent a measuring gauge formed as an integral part of one of the panels. The reservoir is adjustable to obtain a zero reading prior to a measurement. The reservoir is exposed to the ambient during measurement by selective manipulation of a reservoir cap assembly.

Abstract: A corona discharge device has a cleaning assembly for cleaning both its corona discharge electrode and a conductive shield partially surrounding the electrode. The cleaning assembly includes a wiper which is in contact with both the electrode and the shield, and movement of the wiper within the discharge device effects cleaning of both the electrode and the shield.