Method of molding insulation about a metal pipe

Claim 1

A METHOD OF INSTALLING IN A FIELD INSTALLATION INSULATED METAL PIPE HAVING HIGH SERVICE TEMPERATURES IN THE RANGE FROM 300* TO 800* F. WHICH COMPRISES: (A) DIGGING A TRENCH ADAPTED TO RECEIVE SAID PIPE AND EXCEEDING THE SIZE OF SAID PIPE BY THE AMOUNT OF DESIRED INSULATION; (B) LINING SAID TRENCH WITH A NON-POROUS WATER-RESISTANT MATERIAL; (C) SPACING SAID PIPE IN SAID TRENCH BY MEANS OF SUITABLE THERMALLY NON-CONDUCTIVE SUPPORTS; (D) INTRODUCING INTO SAID TRENCH, ALONG SAID PIPE, A MIXTURE WHICH, UPON CURING, IS CONVERTED INTO A RIGID CELLULAR EPOXY RESIN WHICH SURROUNDS SAID PIPE; (E) THEREAFTER, MAINTAINING THE TEMPERATURE OF SAID PIPE AT NO MORE THAN ABOUT 160* F. FOR A SUFFICIENT TIME TO PERMIT THE CURE OF SAID RESIN TO BE SUBSTANTIALLY COMPLETE; (F) THEREAFTER INCREASING THE TEMPERATURE OF SAID PIPE UP TO ITS SERVICE TEMPERATURE IN SAID RANGE; (G) AND, AFTER SAID CURE IS AT LEAST SUBSTANTIALLY COMPLETE, REMOVING AN UNDESIRED EXCESS OF RESIN FOAM AND COVERING THE EXPOSED SURFACE OF THE FOAM WITH A WEATHER-RESISTANT MATERIAL.