Family Owned & Operated Since 1971• Bakersfield, CA
SKU: 405
Compact primary element with three sensing technologies in one form factor — 405 (standard orifice plate), 405C (patented 4-hole conditioning orifice), or 405A (compact annubar / averaging pitot). Wafer-style installation between standard process flanges; no separate manifold or flange union required. The conditioning orifice (405C) variant requires only 2 diameters of straight pipe upstream and downstream — best in tight piping. Used as a low-cost, drop-in solution for closed-loop control, general-purpose flow monitoring, and lower-tier custody transfer.
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Compact primary element with three sensing technologies in one form factor — 405 (standard orifice plate), 405C (patented 4-hole conditioning orifice), or 405A (compact annubar / averaging pitot). Wafer-style installation between standard process flanges; no separate manifold or flange union required. The conditioning orifice (405C) variant requires only 2 diameters of straight pipe upstream and downstream — best in tight piping. Used as a low-cost, drop-in solution for closed-loop control, general-purpose flow monitoring, and lower-tier custody transfer.
The Rosemount 405 Compact Primary Element # 405 is manufactured by Rosemount. Valley Instrument Service is an authorized Rosemount dealer offering full sales support, NIST-traceable calibration, and expert technical assistance.
Our team can help with product selection, specs, pricing, and application support.
Contact Us or Call (661) 327-8681Compact wafer-style orifice flow element. Available as 405P (standard concentric orifice plate) or 405C (patented 4-hole conditioning orifice for short-straight-run installations). Drops between standard process flanges with no manifold or flange union required. Used as the orifice in 2051CFC / 3051CFC / 3051SFC assembled DP flow meters.
Rosemount is configurator-heavy and quote-only — Valley Instrument verifies option compatibility, lead time, and pricing before confirming your order.
Integral orifice primary element for small line sizes (0.5 - 1.5 in. / 15 - 40 mm) — the orifice plate is permanently mounted in a precision-machined meter body, eliminating the centering uncertainty that plagues field-installed plates. Self-centering construction. Best for lab-scale, low-flow, sample-conditioning, and pilot-plant flow measurement where standard orifice fittings are too coarse. Pairs with 3051CFP / 3051SFP / 2051CFP assembled DP flow meters. Wide material variety for chemistry compatibility.
Standard concentric / eccentric / segmental / quadrant orifice plate — the workhorse of differential-pressure flow measurement. Precision-machined per ASME / ISO 5167 standards. Sized to your line size, beta ratio, and material requirements. Used between standard 1496 orifice flange unions for installation. Best for general-purpose flow measurement on clean liquids, gases, and steam where conditioning orifice (405C / 1595) special features aren't needed.
Orifice flange union — paired flanges with integrated tapping points for D-D/2 or flange-tap differential pressure connections. Designed to bolt around a 1495 orifice plate (or any standard orifice plate) and provide stable, leak-free pressure-tap take-offs to the DP transmitter. Slip-on or weld-neck flanges. ANSI 150 through 1500 lb pressure ratings. Carbon steel, stainless steel, or alloy options. The standard installation hardware for orifice-plate flow measurement.
Patented 4-hole conditioning orifice plate — four equally spaced orifices instead of the standard concentric single bore. The four-hole design conditions disturbed flow profiles (eddies, swirl, asymmetry from upstream pipe fittings) BEFORE measurement, eliminating the 10-50 diameters of straight run that ASME orifice plates require. Only 2 diameters upstream and 2 downstream needed — installs in tight piping where standard 1495 plates can't get enough straight pipe. Same materials and beta ratios as standard 1495 plates. Best for retrofit applications and crowded plants.