Abstract: A maintenance platform (10) comprises a main frame (12) with base frames (12,14) releasably interconnected by split clamps (50) and load transfer couplers (52). Upper extension frames (62,64) are mounted on the base frames (12,14). A balcony (82) and stabilizers (100) are also provided. The platform (10) is of modular construction and can be assembled and disassembled manually without tools for use on either improved or unimproved surfaces.

Abstract: A filter system comprises a filter unit and a cleaning unit which cleans the filter unit while the filter unit is operating normally. The filter unit is compartmentalized. During cleaning, an individual compartment is isolated between a pair of ducts of the cleaning unit and is cleaned by applying pulses of a cleaning fluid to one of the ducts and suction to the other duct. The filter unit is rotatable relative to the cleaning unit to align successive compartments of the filter unit with the cleaning unit.

Abstract: Apparatus for delivering cryogenic liquid from a supply vessel to a plurality of receiver vessels employs a subcooler that operates at atmospheric pressure. A supply hose delivers cryogenic liquid from the supply vessel to the subcooler, and coaxial hoses deliver cryogenic liquid from the subcooler to the receiver vessels. The subcooler has an inner chamber surrounded by an annular vent space. A predetermined level of cryogenic liquid is maintained in the inner chamber. Cryogenic vapor from the inner chamber continuously vents to atmosphere via the annular vent space. Cryogenic liquid from the supply hose passes through a heat exchanger in the inner chamber to an inner tube of each coaxial delivery hose, the outer tube of which has one end open to the liquid in the inner chamber and has its other end sealed. The delivery hoses are stored in an upright position, so that the inner and outer tubes thereof become filled with cryogenic vapor under pressure.