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Precision air-floating shock absorbers can provide vibration reduction at very low frequencies for measuring instruments, electron microscopes, nuclear magnetic resonance equipment, measuring triads, and precision machining equipment.
The Fabreeka Precision Air-Floating Damping System uses servo-controlled air springs. This type of damper is ideal when it is necessary to control both height and vibration. Fabreeka PAL shock absorbers meet the strict requirements of measuring instruments, electron microscopes, inspection equipment and precision machining equipment.
PAL Damper Description The standard Fabreeka PAL damper has a natural frequency as low as 1.7Hz. Some custom products can have a natural frequency as low as 0.5Hz.
The complete Fabreeka PAL system contains at least 3 active vibration absorbers (since 3 points determine a plane). Each damper has a leveling valve, which is a load cell and height control unit.
The number of dynamic dampers required can be increased depending on the weight of the equipment.
PAL shock absorber performance
The PAL damper can automatically return to the original horizontal position, which in turn reacts quickly to changes in the supporting load and the shifting of the center of gravity.
The performance of an air-buoyed shock absorber system requires adjustment of the inherent factors of the shock absorber, the accuracy of the leveling valve, and the system return stabilization time.
The vibration damping system will be equipped with a control box, automatic height control valve, connection piping and other accessories for installation.
It refers to the time when the shock absorber returns to the initial setting position. This disturbance can be external or caused by the machine itself, such as the operation of a gantry hanger or machine.
The shortest recovery settling time depends on the optimum damping and the corresponding valve flow. Air-floating dampers that respond to excessively long settling times are unacceptable, as precision measuring and positioning machinery may cause repetitive errors and reduced productivity.
For different cases, Fabreeka can provide different leveling valves. In the design of a vibration damping scheme, the valve's flow, stiffness, and accuracy are the main parameters. Fabreeka's leveling valve can be +/- 0.15mm or +/- 0.025mm. Valve flow and stiffness can be selected based on damper design and damping.
PAL shock absorber characteristics / specifications
Natural frequency | （-6） | （-12） |
vertical | 2.5-2.7Hz | 1.5-1.7Hz |
Level | 2.0-4.5Hz | 2.0-4.5Hz |
PAL shock absorber size
* Actual size may vary, please check with Belkin *
Damping
Vertical (adjustable) | 6%-20% | 6%-20% |
Level | 5%-6% | 5%-6% |
Product specification table:
H | H |
| Max Lifting Capacity | ||||
Type | D1 | D2 | Deflated | Max.Lift | L | Ibs | Kg |
PAL 18-6 | 165mm | 152mm | 153mm | 160mm | 234mm | 1,800 | 800 |
PAL 21-6 | 200mm | 150mm | 153mm | 163mm | 270mm | 2,100 | 950 |
PAL 21-12 | 200mm | 200mm | 305mm | 315mm | 270mm | 2,100 | 950 |
PAL 36-6 | 220mm | 190mm | 153mm | 163mm | 290mm | 3,600 | 1,630 |
PAL 55-6 | 260mm | 230mm | 153mm | 163mm | 330mm | 5,500 | 2,500 |
PAL 55-12 | 260mm | 260mm | 305mm | 315mm | 330mm | 5,500 | 2,500 |
PAL 75-6 | 300mm | 265mm | 153mm | 163mm | 370mm | 7,500 | 3,400 |
PAL 133-6 | 380mm | 350mm | 153mm | 163mm | 450mm | 13,300 | 6,030 |
PAL133-12 | 380mm | 380mm | 305mm | 315mm | 450mm | 13,300 | 6,030 |
PAL 255-6 | 530mm | 470mm | 153mm | 165mm | 600mm | 25,500 | 11,560 |
PAL 255-12 | 530mm | 460mm | 305mm | 317mm | 600mm | 25,500 | 11,560 |
PAL 416-8 | 640mm | 585mm | 203mm | 215mm | 710mm | 41,600 | 18,870 |
PAL 1000-6 | 950mm | 910mm | 153mm | 178mm | 1020mm | 100,000 | 45,360 |
PAL 1000-18 | 914mm | 914mm | 450mm | 475mm | 990mm | 100,000 | 45,360 |
Single pendulum damper
With a specially designed airbag, the horizontal natural frequency of the shock absorber can be close to 1.5Hz. In addition, with a single pendulum damper, the natural frequency in the horizontal direction can be as low as 0.4 Hz. The natural frequency of a single pendulum damper can be calculated according to Equation 6, where L is equal to the length of the pendulum.
PAL shock absorber characteristics / specifications
Natural frequency | （-15/-19） | （-36） | （-52/-60） |
vertical | 1.3-1.5Hz | 0.9-1.0Hz | 0.7-0.9Hz |
Level | 1.3-1.5Hz | 0.6-0.7Hz | 0.4-0.5Hz |
* Actual size may vary, please check with Belkin *
Vertical (adjustable) | 6% - 20% | 6% - 20% | 6% - 20% |
Level (adjustable) | 3% - 6% | 3% - 6% | 3% - 6% |
H | H |
| Max Lifting Capacity | ||||
Type | D1 | D2 | Deflated | Max,Lift | D3 | Ibs | Kg |
PAL 21-15P | 200mm | 279mm | 381mm | 391mm | N/A | 2,100 | 950 |
PAL 55-15P | 260mm | 470mm | 381mm | 391mm | 603mm | 5,500 | 2,500 |
PAL 55-52P | 260mm | 470mm | 1321mm | 1331mm | 603mm | 5,500 | 2,500 |
PAL 75-19P | 295mm | 378mm | 483mm | 493mm | N/A | 7,500 | 3,400 |
PAL 133-36P | 380mm | 622mm | 914mm | 924mm | 800mm | 13,300 | 6,030 |
PAL 133-60P | 380mm | 622mm | 1524mm | 1534mm | 800mm | 13,300 | 6,030 |
PAL 255-36P | 530mm | 775mm | 914mm | 926mm | 953mm | 25,500 | 11,560 |
PAL 255-60P | 530mm | 775mm | 1524mm | 1536mm | 953mm | 25,500 | 11,560 |
PAL 416-36P | 640mm | 927mm | 914mm | 936mm | 1143mm | 41,600 | 18,870 |
PAL 416-60P | 640mm | 927mm | 1524mm | 1536mm | 1143mm | 41,600 | 18,870 |
With a specially designed airbag, the horizontal natural frequency of the shock absorber can be close to 1.5Hz. In addition, with a single pendulum damper, the natural frequency in the horizontal direction can be as low as 0.4 Hz. The natural frequency of a single pendulum damper can be calculated according to Equation 6, where L is equal to the length of the pendulum.
On the right, the PAL 133-36P mono-pendulum damper is used to support concrete masses with a mass of 36,000 kg under large nuclear magnetic resonance. The natural frequencies in the vertical and horizontal directions are 1.0 Hz and 0.7 Hz, respectively.
