Plastics granulator knife setting device - has double acting fluid differential piston cylinder with displacement controlled by electric signals

摘要

Device for setting the granulating knives relative to a perforated plate of a plastics granulator in which the knive movement is sensed by electric signal generators is provided with a hydraulic differential piston cylinder coupled to the knife shaft to displace the latter relative to the perforated plate and having large and small dia. pistons whose chambers are connected to a source of hydraulic fluid by a multi-way valve. Line leading from the valve to the small dia. piston is provided with a check-valve, and a line (a) interconnecting the large dia. piston with the valve is fitted with a throttle valve, whilst the lines are interconnected by a releasable check-valve. Releasable side is connected to the line (a) and a pair of presetable control valves are connected in a control line which is connectable to the line (a) by a pressure regulating valve to control the pressure in the differential piston cylinder. Knife wear is reduced with consequential reduction of down-time of granulator.