Flanges and Metering Taps | 8695 Orifice Plate
FLANGES AND METERING TAPS O rifice flanges are used for mounting ½" to 24" orifice plates in the pipeline and the taps on the flanges are used for metering (See bulletin 8763-1 Orifice Flanges). For orifice flanges 1" and below the bolt circle dœsn’t follow ANSI standards. This is because a 1" 300# ANSI flange has the minimum thickness required to accept a flange tap drilling. For sizes less than 1", a blind 1" flange is drilled to the proper diameter to accommodate the smaller pipe. There are 3 types of 8763 flanges, threaded, slip on and weld neck. For the most accurate and precise measurements, weld neck flanges should be used. If slip on flanges are used, the inside face of the pipe should be flush with, or as close as possible to the machined face of flange (some welding standard requirements may not accommodate this). If threaded flanges are used, the pipe threads will not allow the pipe to be flush with the machined face of the flange. The use of threaded and slip on flanges can create an unknown error but have worked satisfactorily for most flow measurements. The pipe
or weld should never extend beyond the machined face of the flange. Assure the flange gaskets do not extend inside the pipe line. When using D, D/2 pressure tappings, 8767 type flanges should be used. 8767 flanges are available in sizes up to 48". D, D/2 pressure tappings are generally used on larger pipe sizes. (See bulletin 8767 ANSI and RPM Flanges).
Corner tap flanges are available upon special request for ½", ¾" and 1" sizes.
Note that all tap types must be selected with consideration for the physical constraints of certain pipe sizes and flange thicknesses. For example a D/2 pipe tap would not fit in a 1" pipe due to fl ange thickness.
Ori fi ce Flanges, Flange Taps D-D/2 Pipe Taps
WARNING: Situations dangerous to personnel and property may exist with the operation and maintenance of any combustion equipment. The presence of fuels, oxidants, hot and cold combustion products, hot surfaces, electrical power in control and ignition circuits, etc., are inherent with any combustion application. Components in combustion systems may exceed 160°F (71°C) surface temperatures and present hot surface contact hazard. Fives North American Combustion, Inc. suggests the use of combustion systems that are in compliance with all Safety Codes, Standards, Regulations and Directives; and care in operation.
Bulletin 8695 Page 3
Corner Tap
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