Abstract: A mixture of two materials flows through a first measuring station which includes a Venturi meter for obtaining and measuring a pressure difference .DELTA.p that is representative of mass flow rate of the mixture and velocity. The mixture then flows through a second measuring station which includes a temperature differential flowmeter in which a predetermined amount of heat is supplied to heat the flowing mixture and raise its temperature to obtain and measure a corresponding change in temperature that is related to the mean density of the mixture and also the square of the mass flow rate. These values .DELTA.p and .DELTA.t are inputs to computer means which functions to solve a third order polynominal or cubic equation and express that solution in terms of the mixture ratio and flow rates of the individual components and the flow rate of the mixture itself.

Abstract: The quality of heat insulation materials is tested and/or compared in a portable structure in which two heat insulation materials are subjected simultaneously to heat flow from a single common metal-clad heating element and the quantity of heat flow through said material is measured and compared. In one case the portable structure has two conveniently accessible cavities within which equal amounts of such insulation, in flat form, may be placed in contact with corresponding opposite sides of a single common metal-clad planar heat source. In a modification of the invention two tubular insulating materials each of the form and type for insulating pipe, is placed around a metal-clad round heating element and the amount of heat flowing from the heating element and through a corresponding one of said materials is measured and compared using individual thermopiles secured to the outer surface of each material.