Abstract: A flow cell for monitoring accumulations of microscopic material in heat exchange systems and the like, by measuring accretion on the surfaces of a pair of plates exposed to a primary flow, includes a split housing which supports the pair of plates in closely spaced relation with an inlet and an outlet positioned to apply a primary flow between the plates, and further includes a cavity formed in each housing half with the back or opposite sides of the plates exposed to the interior of the cavity and fluid inlets and outlets leading into such cavities providing for the flow of a secondary fluid through the cavities and across the back sides of the plates for the purpose of more accurately simulating the thermal gradient conditions on the plates in a heat exchanger, and for monitoring the rate of accumulation on the plate surfaces.

Abstract: A pliable optical prism for use in an optical imaging system such as a fingerprint reader where the prism is physically contacted and the nature of the contact determines the efficiency of the device. The pliable prism deforms under applied pressure to partially mirror the topographic configuration of the source of applied pressure.