Bollin shut-off valves are mostly used in the opening or closing of liquid-pathways. They comprise a cone metal sealing. Should these valves be intendend to serve to the fine regulation of a flow of volume, then we recommend that you apply a regulating-cone (see at regulating-cone). In the following diagram you will find the flow capacity curves of our valves with standard cones. In these diagrams the flow coefficient Kv (Kv = 0,86xCv) is shown in relation to the spindle lift. The flow coefficient Kv is the flow of a volume of water in m3/h with a pressure drop across the valve of dp = 1 Kp/cm2.