Emerson Rosemount 586 Annubar Primary Element

Emerson Rosemount 586 Annubar Primary Element

Introduction

In general industrial flow measurement applications where cost-effectiveness, minimal pressure loss, and maintenance-free operation are top priorities, averaging pitot tube technology offers a compelling alternative to orifice plates, turbine meters, and other traditional flow measurement devices. The Emerson Rosemount 586 Annubar Primary Element is engineered specifically for these general industrial environments, delivering reliable volumetric flow measurement for gases, steam, and liquids across a wide range of pipe sizes.

The 586 Annubar is an insertion-type averaging pitot tube designed for applications where extreme temperatures or bidirectional flow are not required—making it an ideal choice for water treatment facilities, HVAC systems, compressed air monitoring, and general process control. By leveraging the patented T-shaped sensor geometry shared across the Annubar family, the 586 Annubar Primary Element generates a strong, stable differential pressure signal while maintaining the lowest possible permanent pressure loss.

This technical datasheet provides comprehensive specifications, performance data, and application guidance for engineering professionals seeking a cost-effective, low-maintenance solution for general industrial flow measurement.

What Is the Rosemount 586 Annubar Primary Element?

The Rosemount 586 Annubar is a member of the Rosemount Annubar family of averaging pitot tubes, which includes the Rosemount 485 Annubar Primary Element (multivariable measurement with integral temperature), the Rosemount 486 Annubar Primary Element, the Rosemount 585 Annubar Primary Element (severe service, high temperature, bidirectional), and the Rosemount 586.

Unlike a single-point pitot tube that measures velocity at only one location within the pipe, the averaging pitot tube incorporates multiple pressure sensing ports distributed across the pipe diameter. The Rosemount 586 sensor averages these individual velocity measurements to produce a differential pressure signal that accurately represents the average flow velocity across the entire pipe cross-section. This averaging approach significantly improves measurement accuracy compared to single-point devices, particularly in applications where the flow profile may be distorted by upstream piping configurations such as elbows, reducers, or partially closed valves.

The 586 complete flowmeter system consists of the Annubar primary element integrated with a Rosemount pressure transmitter, such as the 3051S, 2051, or 3051CFA series. This integrated solution eliminates the need for separate instrument tubing, fittings, and mounting brackets, substantially reducing installation time and cost.

Key Technical Specifications

General Specifications

Accuracy Performance

Note: As the meter Reynolds Number decreases below the stated limit to 10,000, the accuracy error band increases linearly to ±3.0%. For Reynolds Numbers down to 5,000, the error band increases linearly from ±3.0% to ±10.0%.

Process Conditions

Wetted Materials

The 586 Annubar Primary Element is available in 316/316L Stainless Steel as the standard wetted material for general industrial applications requiring corrosion resistance and durability.

Sensor Surface Finish

The front surface of the Annubar primary element is textured for high Reynolds number applications, typically encountered in gas and steam service. This surface texture creates a more turbulent boundary layer on the front of the sensor, producing a more predictable and repeatable flow separation point at the sensor’s edges—enhancing measurement stability and signal quality.

Fluid Compatibility

The Emerson Rosemount 586 Annubar Primary Element is suitable for measurement of:

Important Note: Unlike magnetic flow meters (such as the Rosemount 8711 and 8721 series), the 586 Annubar does not require conductive fluids. It can measure any fluid—conductive or non-conductive—as long as the fluid is clean enough to prevent clogging of the sensing ports.

Limitation: Annubar averaging pitot tubes are unsuitable when dirty or sticky fluids are used, as particulate accumulation can block the pressure sensing ports over time.

Key Features and Design Advantages

Patented T-Shaped Sensor Geometry

The Rosemount Annubar primary element features a proprietary T-shaped cross-section that creates a fixed flow separation point across a wide range of flow velocities. The flat upstream-facing surface of this sensor creates a fixed separation point to increase the DP signal and improve performance over a wider flow range. The back side of the sensor includes stagnation zones positioned to reduce signal noise and resist clogging caused by process particulates. This design produces a stronger, more stable differential pressure signal while reducing signal noise compared to other averaging pitot tube shapes.

Minimal Permanent Pressure Loss

Because the 586 Annubar sensor maintains a small profile within the pipeline, it generates significantly lower permanent pressure loss compared to orifice plates, venturis, or other constriction-based DP flow meters. This low pressure drop translates directly into energy savings—whether through reduced compressor work for gases, lower pumping power for liquids, or decreased fuel consumption for steam generation. Over the life of a compressed air system or steam line, these energy savings can substantially exceed the initial capital cost of the flowmeter.

No Moving Parts

The 586 Annubar Primary Element contains no moving components, eliminating wear-related failure modes and reducing maintenance requirements. Calibration intervals can extend up to 10 years under normal operating conditions with clean fluids, delivering significant maintenance cost savings.

Lightweight Design for Large Line Sizes

At larger pipe diameters, the Annubar sensor’s insertion design offers substantial weight and cost advantages over full-bore flow meters. A 96-inch Annubar primary element weighs a fraction of an equivalent spool-piece flow meter, reducing shipping costs, installation labor, and structural support requirements.

Variable Mounting Options

The Annubar family offers several mounting options to meet a wide range of process demands. The 586 sensor is compatible with:

Flanged assembly — Fulfills structural requirements for high-pressure applications

Pak-Lok option — Uses compression design to firmly secure the sensor

Compact design — Easily installs between raised-face flanges for space-constrained installations

Single-Pipe Penetration (with MultiVariable Transmitter)

When combined with the capabilities of the Rosemount 3051S MultiVariable Transmitter, the Annubar flowmeter offers differential pressure, temperature, and flow readings via a single device, reducing the need for multiple pipe penetrations. This scalable solution updates 22 times per second and provides easy maintenance without requiring process shutdown.

Installation Guidelines

Upstream and Downstream Straight Pipe Requirements

Proper installation is critical to achieving specified accuracy. The following minimum straight pipe lengths are recommended:

For a single elbow out of plane, 10 diameters upstream and 4 diameters downstream are recommended.

Sensor Positioning

The 586 Annubar sensor must be installed with the sensing ports properly oriented relative to the flow direction. The sensor’s identification tag indicates the correct flow direction, and the T-shaped profile must be positioned with the high-pressure ports facing upstream. For horizontal pipelines when measuring gases, the sensor should be installed with a minimum 5-degree upward angle to allow condensate drainage.

Transmitter Integration

The 586 primary element can be integrated with several Rosemount transmitter platforms:

Rosemount 3051SFA — Compact Annubar Flowmeter with integral transmitter

Rosemount 3051CFA — Annubar Flowmeter with coplanar transmitter mounting

Rosemount 2051CFA — Cost-effective Annubar Flowmeter solution

Each transmitter option supports HART, Foundation Fieldbus, Modbus, or WirelessHART communication protocols, enabling seamless integration into existing control system architectures.