The weighted particle method for convection-diffusion equations

The dual level toilet flusher is a toilet tank flush mechanism which permits the user to either flush the full tank of water or to flush a lesser preset volume of water, depending on the direction of rotation of the flush handle. The flush mechanism incorporates a float valve fitted with a slidable ballast which changes the flotation characteristic of the float valve, to cause the valve to assume a negative buoyancy and close at one of two levels of water in the tank, depending on the position of the slidable ballast. The flush handle is fitted to a shaft of non-circular cross section which rides in shaped openings in each of two lever arms inside the tank, so that rotation of handle and shaft in one direction causes rotation of only one of the lever arms and rotation of the shaft in the opposite direction causes rotation of only the second lever arm, with the position of the slidable ballast oriented with respect to the float valve by the lever arm which is rotated, with rotation of either lever arm raising the float valve.