The Daniel Orifice Flange Unions are precision-engineered flange fittings designed for use in differential pressure (DP) flow measurement and metering systems, providing reliable connections for orifice plate installations, DP transmitter impulse lines and high-accuracy flow metering in demanding industrial environments.
Manufactured to stringent quality and dimensional standards, these flange unions ensure accurate alignment, leak-tight sealing and robust mechanical performance across a wide range of line sizes and pressure ratings making them ideal for custody transfer of oil and gas, pipeline flow measurement, allocation metering and process control systems in UK oil & gas transmission and distribution pipelines, terminals, refineries, petrochemical plants, offshore platforms and large process facilities.
Designed to reduce installation time and simplify maintenance, Daniel orifice flange unions support consistent impulse line geometry and eliminate many common field assembly issues, helping maintain DP transmitter performance and improve long-term measurement stability for critical flow metering applications.
Every Daniel OFU is expertly manufactured to meet or exceed AGA 3/API 14.3 standards.
See our pressure transmitters and Differential Pressure measurement instruments
- Bore Tolerances are well within the latest recommendations of API-14.3.
- Pressure Tap Hole Location is closely controlled. Tap hole centres are 0.938-in from bearing faces of raised face flanges, placing their centreline 1-in from the face of the orifice plate when 0.063-in gasket thickness is included.
- 1. For 3-in and smaller flanges, tap location tolerance is ± 0.016-in.
- 2. For 4-in and larger flanges, tap location tolerance is ± 0.031-in.
- Pressure Tap Holes – Tap hole edges on the flange bore surface are carefully inspected to be free from burrs. All roughness is eliminated. Sizes are shown in the following tables.
- Flange Tap Connections – Standard connections are .50-in NPT. Other sizes and types are available on request.
- Gaskets – Two 0.063-in thick(1) precision die-cut gaskets are furnished with all raised face orifice flanges. Non-asbestos gaskets are standard.
- Dowel pins: Alignment dowel pins of the knock-out type are furnished as standard on all 2-in to 8-in raised face orifice flanges. These dowel pins assure correct alignment of the flange bores as well as centering the orifice plate bore to the flange bores within the tolerances of API-14.3.
