Pneumatic And Hydraulic Equipment Page 104

Cushion Energy Absorption Cylinders with air cushions provide a possible solution to destructive energies. The air cushion traps a small amount of exhaust air at the end of stroke, providing an air pocket that decelerates the load. This reduces the potentially destructive energy being transmitted to the cylinder and other components. The following is a brief explanation on how to determine the energy level of your application and decide if an air cushion can provide adequate energy absorption. For a more detailed description, consult the John Henry Foster Company. Step 1. Determine the load to be stopped by the cylinder. Step 2. Determine the velocity at which the load impacts the cylinder endcap. Step 3. Calculate the energy the cylinder generates. Use the following equation: energy (e) = w = weight of the load (lbs.) V = velocity of the cylinder as the piston impacts the endcap (feet per second) p = driving pressure (psi) k = bore constant Example:C-316-D at 80 psi with total load of 8 lbs. driving pressure (p) = 80 psi total load (w) = 8 lbs. bore constant (k) = .24 maximum velocity (v) = 6 fps = (8/64) x (6 2 ) + (80 x .24) = 23.7 ft. lbs. w (- x v 2 ) + (p x k) 64 ORIGINAL LINE-AIR CYLINDERS WITH ADJUSTABLE CUSHIONS Maximum Energy Calculation Data Bore Max Energy k (ft-lbs) 04 4.47 0.03 09 10.40 0.05 17 18.80 0.11 31 27.60 0.24 50 40.11 0.37 70 77.72 0.58 Cushion Lengths 0.75" 0.90" 0.99" Bimba (314) 427-0600 800-444-0522 (FAX) 314-427-3502 www. j hf.com JHF Catalog [ Volume 7 ] 104 Prices Subject to Change Without Notice John Henry Foster pneumatic and hydraulic equipment

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