Balance Pan Damping Using Rings of Tuned Sloshing Liquids

This paper describes a new method to damp out balance pan oscillations, even when the balance is operated in a vacuum. The key is to tune the wavelength of the damping liquid by adjusting the depth. The liquid is sealed in a vacuum-compatible container attached above the pan, and the time that the wave travels from one side of the container to the other can be adjusted for maximum damping at the natural pendulum frequencies of the pan. We are investigating the practical application of this damping approach in our respective watt-balance experiments. It is shown that the channels in the shape of rings filled with liquids to the optimum depth work well.