METHOD FOR DETECTING THE FLOW RATE OF A GAS IN A MAIN PIPING AND DEVICE FOR THE MEASUREMENT OF THE FLOW RATE OF A GAS IN A GAS PIPING

摘要

A device (110) for the measurement of the flow rate of a gas in a main gas piping (111), comprising: - first branch means (180) with a first branch pipe (112), developing inside a main piping (111) according to a second direction (X2) at least in part transversal to a first direction (X1) of said main piping (111); said first branch pipe (112) being configured for the diversion of a portion of a gas flow in transit in the main piping (111) towards measuring means (113), - measuring means (113), comprising an inlet mouth (114), connected to the first branch pipe (112), and an outlet mouth (115), said measuring means (113) being configured for the direct measurement of the flow rate of the portion of gas flow, diverted by the main piping (111), which crosses the same measuring means (113), - and second branch means (181), which in turn comprise a second branch pipe (116) connected to the outlet mouth (115) and configured for the reintroduction into the main piping (111) of the diverted portion of gas flow crossing the measuring means (113), wherein - said first branch pipe (112) and said second branch pipe (116) are concentric, said first branch pipe (112), comprising an external sampling tube (117), developing according to a second direction (X2) orthogonal to the first direction (X1), said sampling tube (117) crossing the wall (120) of said main piping (111) at a through hole (119) defined on the same wall (120), - said sampling tube (117) having at a first end (117a) a connecting section for the connection with said measuring means (113), - said sampling tube (117) having a second end (117b), opposite to the first end (117a), closed, and being positioned in such a way that said second end (117b) is close to or in contact with the internal surface of said wall (120), - said sampling tube (117) having three lateral sampling holes (121, 122, 123), said lateral sampling holes (121, 122, 123) being open, and turned, in the direction opposite to the direction of a gas flow (F) in the main piping (111), - said second branch pipe (116), having a lateral return hole (132) turned in the same direction towards said gas flow (F), - said second branch pipe (116) comprising a return tube (130), developing according to a third direction (X3) orthogonal to said first direction (X1) and coinciding with said second direction (X2), - said lateral return hole (132) comprising a tubular section (136) positioned between said return tube (130) and said sampling tube (117), so as to create a passage between the second branch pipe (116) and the inside of said main piping (111).