Article Needle Valves (D311b98) A Stainless Steel ring around the housing indicates in colour coded form the status of the needle valve: isolate (blue), vent (red) or equalise (green).When the flow stops or reverses, the disk or ball is forced onto the seat of the valve by both the backflow and gravity. EBRO is acknowledged as one of the world's leading manufacturers of valves and control components. In the pictured single-stage regulator, a diaphragm is employed with a poppet valve to control pressure.Crane Cast Steel Class 150, 300 and 600 Gate Valves, Globe Valves, Swing Check and Tilting Disc Check Valves. There are certain types actuators of ball valves or butterfly valves that manipulate the flow rate of the solution by opening or closing the valve stem a to a certain degree.When ball is full open or close position,the transmitter substance in center cavity of body can be released by drainage and emptying addition,the over loaded pressure in the center cavity of valve can b