US Patent 7364702 Liquid dispensing device

A liquid dispensing device. The liquid dispensing device has a tray for holding a liquid at a relatively constant level. A syringe is used for drawing fluid from the tray. A liquid container containing a liquid is positioned upside-down in the tray such that the opening of the liquid container defines a vertical position that is slightly below the liquid level in the tray. Atmospheric pressure on the liquid in the tray and a vacuum inside the liquid container prevents liquid from draining from the container until the fluid level in the tray drops to a level approximately equal to the vertical position of the opening. The positioning of the syringe for drawing fluid is simplified by reason of the fact that the level of fluid in the tray is maintained at an approximately constant level despite withdrawal of quantities of fluid from the tray.