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Power tank
Page 103
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A means of maintai ing hydraulic assistance to p wer-steering systems in the event of failure of the hydraulic pump or vehicle engine is afforded by the Automacc introduced by Hydrotrole. This is a hydro-pneumatic accumulator unit which is fitted after a ball-check in pressure supply to the steering servo.
The Automacc unit is essentially a pressure vessel separated across its diameter by a special plastics diaphragm. The top half of the vessel is precharged with nitrogen at a pressure below that of the hydraulic steering system. When the vehicle engine is Istarted, oil is pumped into the vessel so compressing the nitrogen gas until the system pressure is reached. If the pressure from the hydraulic pump fails the pressure stored in the compressed nitrogen provides pressure to the steering servo at a progressively diminishing rate. This makes the driver aware of a fault but gives adequate power assistance for him to drive the vehicle off the road. This is much safer than a driver being suddenly faced with a complete loss of power assistance to his steering.
Made by: Hydrotrole Ltd., Rooth Street, Georges Road Industrial Estate, Stockport, Cheshire.