GB314120A - Improvements in or relating to fluid flow meters and valves - Google Patents

Abstract

314,120. Vickery, T. March 23, 1928. ' Liquid-meters.-A change over valve for use in installations using high and low reading fluid flow meters is fitted with a dashpot arranged sc that the initial down. ward movement is damped and is slower than the correspond ing damped fina upward movement and so that the re mainder of the valve movement is un damped. The valve member 11 is loaded by a weight 17 and is provided with tubular part 12 having tapered ports 14 with rectangular lower portions. The valve seat has ports 13 leading to a chamber 9 connected to the low reading meter so that when the valve is in its lowest position fluid entering at 7 passes exclusively to the smaller meter. As the valve rises the ports 13 are closed and the fluid flows through the connection 5 to the larger meter. The dashpot comprises a cup leather piston adapted to work in a cylinder 20 having two ports 21, 22 near its lowest end. After an initial movement of the piston, fluid passes through the port 21 and chamber 23 to the cylinder in which it is trapped when the piston passes the port 22, only escaping past the cup leather. The downward movement is retarded by the vacuum formed above the piston. To prevent the piston being held in its raised position a small hole may be formed in the upper part of the cylinder.