Brick Pressing Rate Calculations

Introduction

Under the assumption of incompressible flow and fixed hydrauilic cylinder volume, the brick pressing rate of The Liberator can be calculated for a given hydraulic flow rate.

The Liberator

The Liberator uses a 5x8x2 inch cylinder (diameter x length x rod diameter) for pressing, and a 2.5x14x1.5" cylinder for the soil loading drawer.

The effective volumes for both cylinders differ. This is because the cylinder rod takes up some volume - thereby reducing effective volume and force for the contraction part of the stroke. The expansion part of the stroke uses the full cylinder volume.

Main Cylinder Volume, D= 5 inches, D_rod=2 inches

• Cylinder volume (expansion volume)
• Rod volume
• Cylinder volume-rod volume (contraction volume)
• Volume filled for a complete cycle of the cylinder (expansion volume + contraction volume)

Secondary Cylinder Volume, d=2.5 inches, d_rod=1.25 inches

• Cylinder volume (expansion volume)
• Rod volume
• Cylinder volume-rod volume (contraction volume)
• Volume filled for a complete cycle of the cylinder (expansion volume + contraction volume)