TEMPERATURE CONTROL SYSTEM FOR ELECTRICALLY HEATED HOSE UTILIZING HOSE SIMULATOR TEMPERATURE DETECTION

摘要

In coating systems wherein multiple coating components are separately applied by a hose to the point of application and are mixed and applied by a common applicator gun to a surface, e.g., the application of a urethane foam coating to a building roof, the quality of the applied coating is dependent upon the temperature of the coating components as well as the temperature of the surface to be coated, the latter temperature being proportional to the ambient temperature in the vicinity of the point of application. To insure optimum coating quality, the invention incorporates into the hose (16) a heating tape (40) having a resistance heating element (44) closely controlled by an electronic temperature control circuit (18) responsive to both an ambient temperature sensor (22) comprising temperature sensitive resistance (R3) and a hose simulator (60) separated from the hose (16) and having heat loss and absorption characteristics similar to the hose (16) and including a temperature sensing element (70) potted together with a resistor (58) in a mass of epoxy compound (59) to form a module (62) wrapped in an insulation blanket (64). The resistor (58) and sensing element (70) are spaced apart a predetermined distance selected to provide a degree of heat correlation comparable to the rate at which the hose (16) accepts heat from the heating tape (40) so that the temperature of the simulator (60) tracks the temperature of the hose (16) nearly identically.