| 摘要 |
A system for keeping a reservoir solution of urea in a liquid state at normally sub-freezing temperatures comprising a reservoir tank module having a heater and disposed in a solution storage tank. Solution in the storage tank is heated by passage of heat through the walls of the reservoir tank module which are formed of a hybrid of plastic polymer and metal, preferably a urea-resistant stainless steel, such that the thermal conductivity of the walls is sufficient to liquefy frozen solution in the storage tank in a practical time frame at an acceptable net manufacturing cost for the tank module. The hybrid combination may be formed in any of various arrangements such as, but not limited to, a lower portion formed of metal and an upper portion formed of plastic, or alternating bands and/or strips of metal and plastic. The optimum thicknesses of metal and plastic may be determined conventionally.
|
