Connecting the two sides of the piston in a double-acting, double-rod cylinder through an external adjustable flow control needle valve, transforms the cylinder into a fluid viscous damping device (VDD). Vibrational motion prompts the fluid to transfer from one piston side to the other via the flow control valve, dissipating vibration energy due to the resulting pressure drop. Fine-tuning the damping coefficient is achievable by regulating the valve’s opening. Moreover, integrating a bladder accumulator complements these damping systems, pressurized with nitrogen on one side and storing fluid on the other, ensuring compensation for any gradual fluid loss through the seals over time.
DEICON tested one such viscous damping device (VDD) by subjecting it to harmonic motion at 6 different frequencies with 6 different amplitudes (of motion), while measuring the force as well as the extent of motion. The test runs were done with two different openings ‘large’ and ‘small’ of the flow control needle valve. As expected, the damping coefficient of the VDD is inversely related to the extent of opening of the flow control needle valve; i.e., the larger the opening, the lower the damping coefficient. Figure 2 depicts the two settings of the needle valve opening.
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