A Rolling Steel Mill Had Trouble With the Roll Removal Circuit Trying To Eject a Roll

The circuit for the roll removal system is commonly called a part time Regen (regeneration) allowing the rod flow to join the pump flow moving the cylinder at a fast rate and when encountering a load, the speed would drop to a steady slow rate as the cap end pressure increased. The 1.3 mm (0.050”) orifice prevented the rod side pressure from intensifying and reducing the total extension force. The drawing showed a 0.5 mm (0.020”) orifice that was blocked causing this problem. Just another note, when they found the blocked orifice in a fitting, they also discovered it was a 0.5 mm (0.050”) size, and not as shown on the drawing. The builder must have changed it to a larger size to acquire the slower speed and the high force they needed.