Linear Hydraulic Actuator Sizing

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HYDRAULIC ACTUATOR SIZING To use the Actuator Sizing Table below, the following information is required: Required maximum valve (load) thrust in pounds (T) Required valve (load) stroke in inches. (S) If a hydraulic power source is available, the minimum oil pressure.  If Kanair supplies the power unit, the actuator will be sized typically at 2000 psig oil pressure.  If oil accumulators are required for failsafe operation, the sizing pressure will be 1500 psig. Standard maximum working pressure is 3000 psig,. For spring return actuator, the thrust value should be multiplied by approximately 2.8 to 3.0 times before using the table below.  This is because, apart from providing the required valve thrust, the air supply should furnish sufficient force to overcome the initial spring-preload force and the force to compress the spring. Thus, a spring return actuator will have a bore approximately 70% larger than its double acting equivalent.  Because of the variation of available thrust values during the actuator stroke, it is possible to optimize the spring size based on the specific load profile required.  Consult kanair for details. The valve thrust and stroke can be obtained from the valve manufacturer. If the actuator is retrofitted on an existing valve, these values can be measured and/or estimated reasonable accuracy by knowing the valve parameters, valve size and the differential pressure across the valve.  Consult Kanair for details. LINEAR HYDRAULIC  ACTUATOR SIZING MODEL NO. BORE (inch) ACTUATOR THRUST AT VARIOUS PRESSURES OIL PRESSURE IN PSI 500 1000 1500 2000 2500 3000 HL 1.5 x * - DA 1.5 730 1,460 2,191 2,921 3,651 4,381 HL 2 x * - DA 2 1,178 2,356 3,534 4,712 5,891 7,069 HL 2.5 x * - DA 2.5 2,062 4,123 6,185 8,247 10,308 12,370 HL 3.25 x * - DA 3.25 3,405 6,811 10,216 13,622 17,027 20,433 HL 4 x * - DA 4 5,081 10,161 15,242 20,322 25,403 30,483 HL 5 x * - DA 5 8,247 16,493 24,740 32,987 41,234 49,480 HL 6 x * - DA 6 11,683 23,366 35,048 46,731 58,414 70,097 HL 7 x * - DA 7 15,708 31,416 47,124 62,832 78,540 94,248 HL 8 x * - DA 8 24,438 48,875 73,313 97,750 122,188 146,625 HL 10 x * - DA 10 31,318 62,636 93,953 125,271 156,589 187,907 HL 12 x * - DA 18 44,670 89,339 134,009 178,679 223,348 268,018 * above denotes the valve stroke (minimum cylinder stroke required)

Example: Double Acting Actuator Required Valve Thrust , T .................................... = 31,000 lbs. Safety Factor Used............................................... = 10 % Thrust Value for Actuator Sizing (1.1 x 31000)...... = 34,100 lbs. Minimum Hydraulic Pressure (for use with an Accumulator System for Fail Close) = 1,500 psig From Table I, Cylinder Bore Required................... = 6" ( 6" bore actuator provides 35,048 lbs thrust at 1500 psig oil pressure. Valve Stroke Required (say, for 6" gate valve).... = 7.5" ACTUATOR MODEL SELECTED..................... = HL 06x 08-DA Because of physical limitation for commercial spring manufacturing, available thrust from spring return actuator is limited.  The spring limitation is controlled by both the stroke length as well as thrust.  Contact us for your specific application.

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