Meriam 70H_72H High Pressure Wet Tap Accutubes with Integral 3-Valve Head and Optional RTD - Manual (Page 25)

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4.9.1 Ducts
The mounting technique for circular and rectangular ducts is most frequently the
same as used for pipe in which a threaded coupling is welded in place. In
instances where the duct wall is too thin to permit welding, a sheet metal flange
option is available for bolt mounting. The flange is to be used with a user
provided gasket or sealant between the flange and the duct. The surface of the
duct where the gasket lays must be cleaned prior to application. All other
standard instructions remain unchanged. This type of mounting is limited to
pressures below 3 PSI.
4.9.2 Saddle Clamps
Saddle clamps are used in applications where welding is not desired or possible.
Saddle clamp mounting is accomplished by preparing the area around the hole
that has been drilled. The gasket on the saddle clamp is placed around the hole
and the unit is then bolted in place. It is important to bolt the saddle clamp as
tightly as possible without damage to the pipe. All other instructions for the
standard models apply.
4.9.3 Rotated Head
When mounting an Accutube in a vertical steam or liquid line, it is
recommended that a rotated head be used. This head is rotated 90
° clockwise
with respect to the standard head orientation (Figure 1.2). The rotation prevents
false differential pressure that would otherwise be created due to the interior
construction of the Accutube instrument head.