Abstract: There is described a pressurized filtration system for removing suspended solids from a liquid which comprises two enclosed filter vessels each containing either a removable filter bag or cartridge. The vessels are located in parallel in the circulation line of a pump which pumps the liquid from a bulk storage vessel through only one filter vessel at a time, this being controlled by a valve system in the circulation line to the filter vessels. Liquid forced through the filter vessel in use is pumped to a liquid storage vessel via a non-return valve located in the outlet line from each vessel, the outlet from each vessel having a branch connection to a shuttle valve, the outlet from which is connected via a non-return valve to the suction side of the pump, whereby when liquid is being pumped through one vessel the shuttle valve is shut against the flow of liquid therethrough but is open on the other side so that the liquid can be sucked out of the other vessel.

Abstract: An electrolytic metal recovery cell is described in which a cylindrical cathode is mounted for rotation in a housing having an inlet and outlet for solution from which metal is to be recovered. The housing contains an anode and a cutter blade is mounted so as to be capable of removing metal deposited over the whole face of the cathode when the cell is in use. In order to control the operation of the cell, electrical means are provided for operating the cutter blade at predetermined intervals of time irrespective of the electrolysis conditions and for operating the cutter blade when a monitored cathode potential deviates a predetermined amount from a desired value.By this means the use of previously proposed scrapers and their attendant disadvantages are avoided and the cell can be easily controlled either under steady state electrolytic conditions or even when there are large variations in the concentration of the metal ions in solution.

Abstract: A method of drying processed polyethylene coated photographic paper in an enclosed drying chamber through which the exposed and processed polyethylene coated photographic paper bearing an image on one side of its sides is made to travel.This comprises directing radiant heat onto the non-image bearing side only of the paper as it travels through the drying chamber and as a stream of air flows over the image bearing side of the photographic paper.The advantage of this invention over drying apparatus at present commercially available is that less heat energy is required to dry large photographic sheets.