Application of the formula for the average Dupuis filtration rate constant and variable values of the hydraulic transfer allows styled conservative and non-conservative impurities Linearizability equation. Concentration distribution is linked to the solution of the problem for at least a positive functional. For small values of the filtration Rayleigh number extremal trajectories differ little from the transport equation. In the «big» Rayleigh numbers exist extremals implement minimum concentration change of temperature and heat flow, ie maximum heating of the wall hot air filter.