Linear Hydraulic Actuator Sizing

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HYDRAULIC ACTUATOR SIZING

To use the Actuator Sizing Table below, the following information is required:

  1. Required maximum valve (load) thrust in pounds (T)

  2. Required valve (load) stroke in inches. (S)

  3. 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,.

  4. 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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