Abstract: A fluid flow control valve system has a plurality of pairs of 3 port, 2 position (3/2) control valves (6, 6?) each valve being movable between its two positions by a pair of electrically-operable actuators (1, 2). A logic controller selectively generates electrical control signals for independently controlling operation of the pairs of 3/2 control valves, and a circuit means (11) is associated with each 3/2 control valve pair (6, 6?) to receive the control signals and provide electrical outputs to eit actuators (1, 2) of each 3/2 control valve of each pair. Variable switch means (14) forming part of the circuit means (11) pr the actuators (1, 2) to which the output is applied. Varying the switch means (14) programmes the fluid output mode of each 3/2 control valve pair to provide any one of a number of different effective valve types.

Abstract: A fluid flow control valve system has a plurality of pairs of 3 port, 2 position (3/2) control valves (6, 6′) each valve being movable between its two positions by a pair of electrically-operable actuators (1, 2). A logic controller selectively generates electrical control signals for independently controlling operation of the pairs of 3/2 control valves, and a circuit means (11) is associated with each 3/2 control valve pair (6, 6′) to receive the control signals and provide electrical outputs to either of the actuators (1, 2) of each 3/2 control valve of each pair. Variable switch means (14) forming part of the circuit means (11) pre-select the actuators (1, 2) to which the output is applied. Varying the switch means (14) programmes the fluid output mode of each 3/2 control valve pair to provide any one of a number of different effective valve types.

Abstract: A rotary regenerative heat exchanger including a rotatable disc-like matrix having an end seal comprising an arcuate portion and a diametral or chord-wise portion each comprising a pressure plate engaging the adjacent end face of the matrix and an axially-compressible resilient member acting between the housing of the heat exchanger and the pressure plate and defining a space internally of the seal portions communicating with a gallery defined by the housing and arranged to receive a pressurized fluid, the pressure plate of the transverse portion being compressively stressed between spaced parts of the pressure plate of the arcuate portion under cold conditions and the length of the pressure plate of the transverse portion being such that the pressure plates of the seal portions are substantially stress-free under hot working conditions.