... .Glass vacuum tube solar collector, high temperature,antifreeze,vacuum insulation. 2.Copper heat pipe,Start up quickly,transfers heat quickly ... rod,it can increase of service life. 4.High pressure polyurethane foaming insulation,as the prefect density and the ... .Gravity assisted heat pipe, unilateral heat transfer,high efficiency,low heat loss. 7. work under pressure,withstand pressure 1.0MPa,The ...