Azbil Corporation SS2-MVC300-0100 - 7 - INSTALLATION PRECAUTIONS Verity the flow direction mark Verity the flow direction mark on the flow meter matches the process fluid flow direction. Wrong installation causes the inaccurate measurement. Over range flow In case that the steam is released from the downstream of the flow meter to the atmosphere, the steam expands rapidly and its velocity becomes transonic speed. If this happens, the steam exceeds the measurable flow rate range and the steam is not saturated and thus it causes inaccurate measurement. It is strongly recommended to install the value or restriction at the downstream side of the flowmeter. Lengths of straight pipes on the upstream and downstream sides of STEAMcube To generate stable differential pressure, STEAMcube requires that straight pipes on the upstream and downstream sides have at least the lengths shown in Figure 5. D is the bore diameter (line size). For example, 0.5D shows that the length of a straight tube is 0.5 times as long as the bore diameter (line size). Figure 5 shows the specified lengths of straight pipes on the upstream and downstream sides of STEAMcube. If a straight pipe has a length shorter than that specified in Figure 5, output errors may occur. Figure 3 Flow direction mark Figure 4 Over range flow Gate value Gate value Value or Restriction Release to the atmosphere Figure 5 Lengths of straight pipes on the upstream and downstream sides * Valves in this figure are the gate value, ball balue but not globe value. L1 L1 L1 L2 L2 L2 3.5D 0.5 1.5 2.5 3D D L1 L2 L1 L2 1.5 2.5 0.6 0.75D Upstream side L1 Upstream side L1 Direction of flow Direction of flow One right-angle bend Two or more right-angle bends set on the same plane Shrinkage pipe Downstream side L2 Expanding pipe Gate valve (fully open)* All joints shown at left Direction of flow Direction of flow Direction of flow 4 17