GB689474A - Low loss venturi tube - Google Patents

Abstract

689,474. Venturi tubes. KENT, Ltd., G. June 12, 1951 [June 23, 1950], No. 15790/50. Class 69 (i). A venturi tube comprises two truncated cones with their smaller ends adjacent which are separated by a throat of length between 0.03 d and 0.1 d (where d = diameter of the throat), the inlet cone having an included angle between 40 degrees and 50 degrees and the outlet cone having an included angle between 12 degrees and 17 degrees, the arrangement being such that the mouth diameter Dm of the inlet cone is less than the diameter D of the inlet pipe, and in accordance with the equation where K = 0.5 - 0.75. In the form shown, there is an abrupt reduction in area between the cylindrical chamber 3, of same diameter as inlet pipe 2, and the inlet cone 6. The higher pressure offtake 5 is in the chamber 3 and the lower pressure offtake 13 in an annular space 10 formed in the main casing and connected to the throat by the recess 11. A further outlet pipe 15, having a smaller included angle than the outlet cone, may be fitted downstream of that cone, and in a modification the outlet cone is concave from the smaller to the larger end and the tangents to the curved wall at the smaller end have an included angle between 12 degrees and 17 degrees. Specification 473,562 is referred to. The Provisional Specification also describes a venturi tube of similar construction in which the throat length is not greater than 0.1 d, the outlet cone included angle is between 10 degrees and 15 degrees, and the mouth diameter is such that “ to ¢ of the overall gain of kinetic energy is established at the mouth.