Emerson Rosemount 405C Annubar Flow Meter
Model：405C
Manufacturer: ROSEMOUNT
Size: 40*80*25CM
Detail Specification: Annubar Flow Meter
Comment:Carton
Shipping Weight: 20Kg
Estimated Lead Time: 12 Weeks
Payment：T/T
HS CODE：9026809000
product details
Emerson Rosemount 405C Annubar Flow Meter
Introduction
In industrial flow measurement applications where space is constrained and traditional orifice plates cannot be installed due to insufficient straight-run piping, engineers face a difficult choice: compromise on accuracy, invest in costly piping reconfiguration, or accept unreliable flow data. The Emerson Rosemount 405C Compact Conditioning Orifice Plate Primary Element directly addresses this challenge with a patented 4-hole design that conditions disturbed flow profiles, requiring only two pipe diameters upstream and two pipe diameters downstream from the plate.
The 405C Compact Conditioning Orifice Plate is an advanced differential pressure flow primary element engineered for volumetric flow measurement of gases, steam, and liquids. Unlike conventional orifice plates that demand extensive straight-run lengths of up to 40 diameters, the 405C utilizes four equally spaced holes that actively condition the flow profile, enabling stable and accurate measurement even in the presence of upstream disturbances such as elbows, valves, or reducers.
This technical datasheet provides comprehensive specifications, performance data, and application guidance for engineering professionals seeking a compact, low-installation-cost DP flow measurement solution for pipelines from 2 to 12 inches in diameter.
What Is the Rosemount 405C Compact Conditioning Orifice Plate?
The Rosemount 405C is a member of the Rosemount 405 Compact Orifice Series, which includes the 405A Compact Orifice Plate (standard design), the 405C Compact Conditioning Orifice Plate, and the 405P Compact Orifice Plate. What distinguishes the 405C Compact Conditioning Orifice Plate is its patented 4-hole design, which consists of four equally spaced conditioning holes that condition the flow profile, delivering a more stable and accurate measurement even in challenging flow conditions-. Unlike conventional orifice plates that rely on long straight runs to develop a fully developed flow profile, the 405C sensor actively reshapes the flow upstream of the measurement point.
The 405C Compact Conditioning Orifice Plate Primary Element is engineered to install directly between raised-face flanges. This design eliminates the need for impulse piping, isolation valves, fittings, and the associated installation labor. The complete system consists of the 405C primary element integrated with a Rosemount pressure transmitter—such as the 3051S, 3051C, or 2051 series—delivered factory-assembled, calibrated, and pressure-tested, ready for immediate installation-1.
When factory-assembled to a Rosemount 3051S transmitter, the complete assembly is designated as the Rosemount 3051SFC Compact Flowmeter-. The 405C can also be paired with the Rosemount 4088 MultiVariable Transmitter for integrated differential pressure, static pressure, and temperature measurement through a single device-10.
Key Technical Specifications
General Specifications
| Parameter | Value |
| Measurement Principle | Differential pressure (conditioning orifice) |
| Line Sizes Supported | 2 to 12 inches (50 to 300 mm) |
| Line Size – 405C02 | 2 inches (50 mm) |
| Line Size – 405C03 | 3 inches (80 mm) |
| Line Size – 405C04 | 4 inches (100 mm) |
| Line Size – 405C06 | 6 inches (150 mm) |
| Line Size – 405C08 | 8 inches (200 mm) |
| Line Size – 405C10 | 10 inches (250 mm) |
| Line Size – 405C12 | 12 inches (300 mm) |
| Fluid Types | Liquid, gas, steam |
| Accuracy | ±0.5% of flow rate |
| Straight-Run Requirement | 2 pipe diameters upstream, 2 pipe diameters downstream |
| Body Material | 316 Stainless Steel |
| Wetted Materials | 316 Stainless Steel |
| NACE Compliance | NACE MR-0175, ISO 15156 |
| Centering Mechanism | Self-centering ring independent of flange rating |
The 405C provides a flow turndown ratio of 10:1 or greater. For applications requiring wider turndown, the flowmeter system can be configured with the Rosemount 3051S transmitter, which offers up to 200:1 rangedown capability. The 405C02 (2-inch) configuration delivers a beta ratio (β) calculated by 2 × d / pipe size, with β = 0.60-inch (15.24 mm) for the 2-inch line size-.
Pressure and Temperature Limits
| Parameter | Direct Mount | Remote Mount |
| Maximum Working Pressure | ANSI B16.5 600# | ANSI B16.5 600# |
| Maximum Working Pressure (DIN) | PN100 | PN100 |
| Process Temperature Range | -40 to 450°F (-40 to 232°C) | -321 to 850°F (-196 to 454°C) |
| Low-Temperature Limit | -148°F (-100°C) for stainless steel materials | -321°F (-196°C) for remote mount |
The 405C Compact Conditioning Orifice Plate is qualified for extreme low-temperature applications down to -321°F (-196°C) with remote mount transmitter configuration, making it suitable for cryogenic gas measurement including liquid natural gas (LNG) applications. For direct mount configurations, the temperature limit is 450°F (232°C) to protect the mounted transmitter.
Beta Ratio (β) and Bore Sizes
The 405C is available with multiple beta ratio options to match specific flow rate requirements. For the 2-inch line size (405C02 configuration), beta ratio (β) values include 0.40, 0.50, 0.60, and 0.65. For the 3-inch line size (405C03 configuration), beta ratio values include 0.40, 0.50, 0.60, and 0.65. For the 4-inch line size (405C04 configuration), beta ratio values include 0.40, 0.50, 0.60, and 0.65. For the 6-inch line size (405C06 configuration), beta ratio values include 0.40, 0.50, 0.60, and 0.65. For the 8-inch line size (405C08 configuration), beta ratio values include 0.40, 0.50, 0.60, and 0.65. For the 10-inch line size (405C10 configuration), beta ratio values include 0.40, 0.50, 0.60, and 0.65. For the 12-inch line size (405C12 configuration), beta ratio values include 0.40, 0.50, 0.60, and 0.65-.
Beta ratio selection is performed using Rosemount’s Instrument Toolkit sizing program, which provides accurate flow calculations using installation details and fluid properties for the flowmeter-.
Key Features and Design Advantages
Patented 4-Hole Conditioning Design
The defining characteristic of the Rosemount 405C Compact Conditioning Orifice Plate is its patented 4-hole design, which consists of four equally spaced conditioning holes that actively condition the flow profile for stable, accurate measurement-. Unlike conventional orifice plates that rely on long straight runs to develop a fully developed flow profile, the 405C sensor actively reshapes the flow upstream of the measurement point. This innovative design enables accurate flow measurement even under highly disturbed flow conditions caused by elbows, valves, reducers, or other upstream disturbances.
Shortest Straight-Run Requirement in DP Flow Measurement
The 405C Compact Conditioning Orifice Plate requires only 2 pipe diameters upstream and 2 pipe diameters downstream from the plate—a dramatic reduction compared to conventional orifice plates, which typically require 10 to 40 diameters upstream and 5 diameters downstream-11. This 2D upstream and 2D downstream requirement makes the 405C ideal for installation in existing piping with limited straight-run space, eliminating the need for costly piping reconfiguration.
Self-Centering Mechanism
The Rosemount 405C features a self-centering ring independent of flange rating that ensures proper alignment of the orifice plate within the pipeline-. The centering ring can be rotated around the wafer to facilitate centering depending on the orientation of the flowmeter, eliminating the need for field measurements or alignment tools. This simplifies installation and guarantees that the measurement is optimized regardless of piping configuration.
No Impulse Lines or Piping Modifications
The 405C Compact Conditioning Orifice Plate installs directly between raised-face flanges without requiring impulse piping, special flanges, or piping modifications-12. This design eliminates the need for impulse lines, isolation valves, fittings, and the associated installation labor. Compared to conventional DP flow measurement installations, the 405C can achieve over 50% savings in total installed cost-1.
Wide Pressure and Temperature Capability
The 405C is rated to ANSI B16.5 Class 600# (DIN PN100), with a maximum working pressure of 1,440 psig at 100°F. The remote mount configuration supports process temperatures from -321°F to 850°F (-196°C to 454°C), enabling use in cryogenic, ambient, and high-temperature applications-10.
No Moving Parts
The Rosemount 405C 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.
Direct-Mount and Remote-Mount Configurations
The 405C supports both direct-mount and remote-mount transmitter configurations. Direct mount is available for applications requiring transmitter temperatures up to 450°F (232°C). Remote mount is available for applications up to 850°F (454°C), using enough impulse piping to dissipate the process heat to avoid damaging the transmitter-.
Transmitter Integration Options
The 405C Compact Conditioning Orifice Plate Primary Element can be factory-assembled with several Rosemount transmitter platforms:
| Transmitter Platform | Configuration Designation | Key Capabilities |
| Rosemount 3051S | 3051SFC Compact Flowmeter | High performance, advanced diagnostics, 200:1 rangedown |
| Rosemount 3051C | Factory assembly option | Standard performance, HART communication |
| Rosemount 2051C | Factory assembly option | Cost-effective, HART communication |
| Rosemount 4088 MultiVariable | Integrated assembly | Modbus, differential/static pressure, temperature, ±0.05% reading accuracy |
When the 405C primary element is ordered assembled to a Rosemount 3051S transmitter, the new assembly is the Rosemount 3051SFC Compact Flowmeter. See the Rosemount 3051S Series Quick Start Guide for information on configuration and hazardous locations certifications-.
Each transmitter option supports HART, Foundation Fieldbus, Modbus, or WirelessHART communication protocols. The 405C can be used with the Rosemount 4088 MultiVariable Transmitter for multivariable measurements in combinations of differential and static pressure and temperature-10. The 4088 transmitter features enhanced flow accuracy of ±0.05% of reading, LCD display for local data viewing, Callendar-Van Dusen sensor matching for improved temperature accuracy, and reverse wiring protection-10.
Installation Guidelines
Straight-Run Requirements
The 405C Compact Conditioning Orifice Plate requires only 2 pipe diameters upstream and 2 pipe diameters downstream from the plate to achieve ±0.5% accuracy, even when upstream disturbances such as single 90° elbows, double elbows, reducers, or control valves are present. This short straight-run requirement makes the 405C ideal for retrofitting into existing piping where space is limited.
For applications with more severe upstream disturbances, consult the Emerson Configuration Data Sheet requirements.
Mounting Between Flanges
The Rosemount 405C is engineered to install between raised-face flanges using standard studs and nuts. The self-centering ring independent of flange rating comes standard with the 405 Compact Orifice Series and can be rotated around the wafer to facilitate centering depending on the orientation of the flowmeter-. For steam applications, the transmitter should be located below the instrument connections of the 405C to ensure proper condensate drainage.
Remote Mount Connections
For remote mount configurations, use enough impulse piping to dissipate the process heat to avoid damaging the transmitter when measuring high-temperature fluids up to 850°F (454°C)-. For cryogenic applications down to -321°F (-196°C), ensure proper insulation to prevent ice formation on impulse lines.
Factory-Assembled System Installation
If the 405C was ordered assembled to a Rosemount 3051S Transmitter, the complete assembly arrives as the Rosemount 3051SFC Compact Flowmeter, ready for installation with no field assembly required-. The factory-assembled system includes the primary element, transmitter, and all required hardware, leak-tested and calibrated prior to shipment.
Fluid Compatibility
The Emerson Rosemount 405C Compact Conditioning Orifice Plate is suitable for measurement of:
| Fluid Type | Specific Applications |
| Gases | Natural gas, air, nitrogen, hydrogen, process gases, compressed air |
| Steam | Saturated steam, superheated steam (up to 850°F) |
| Liquids | Water, chemicals, hydrocarbons, condensate, cryogenic liquids |
Important Note: The 405C does not require conductive fluids, unlike magnetic flow meters such as the Rosemount 8711 and 8721 series. The 405C Compact Conditioning Orifice Plate can measure any clean fluid as long as it remains single-phase and is clean enough to prevent erosion or clogging of the orifice holes.
Limitation: The 405C is not recommended for dirty or sticky fluids, as particulate accumulation can alter the beta ratio over time and degrade measurement accuracy. For slurry or dirty fluid applications, consider Annubar averaging pitot tube technology.
Comparison: Rosemount 405C vs. Other 405 Series Models
Within the Rosemount 405 Compact Orifice Series, three primary models serve distinct application needs:
| Specification | Rosemount 405A | Rosemount 405C | Rosemount 405P |
| Primary Application | Standard orifice, general | Conditioning orifice, short-straight-run | Standard orifice for pipelines |
| Orifice Design | Single hole | 4-hole conditioning | Single hole |
| Straight-Run Requirement | 10–40 D upstream | 2D upstream, 2D downstream | 10–40 D upstream |
| Accuracy | ±0.5% | ±0.5% | ±0.5% |
| Maximum Temperature | 850°F (454°C) | 850°F (454°C) | 850°F (454°C) |
| Maximum Pressure | 600# ANSI | 600# ANSI | 600# ANSI |
| Line Sizes | 1/2 to 8 inches | 2 to 12 inches | 2 to 12 inches |
| Best Suited For | General applications | Limited straight-run, disturbed flow | General pipeline applications |
The 405C Compact Conditioning Orifice Plate is the ideal choice when upstream straight-run length is limited or when flow profiles are disturbed. The 405A is preferred for standard applications with adequate straight-run. The 405P is designed for pipeline-specific installations.
Comparison: Rosemount 405C vs. Other Flow Meter Technologies
| Technology | Advantages | Disadvantages | Suitability |
| Rosemount 405C | Shortest straight-run (2D), ±0.5% accuracy, no impulse piping, no moving parts | Limited to 12 inches maximum, not for dirty fluids | Limited-space installations, clean gases/steam/liquids |
| Conventional Orifice Plate | Simple, low cost, well-understood | Requires 10–40 D straight-run, impulse piping required | Applications with adequate straight-run space |
| Annubar Averaging Pitot Tube | Low pressure loss, minimal straight-run requirement, larger line sizes | Not suitable for dirty/sticky fluids | Large pipes, gas/steam applications |
| Magnetic Flow Meter | No pressure loss, high accuracy (±0.25%), no straight-run required | Conductive fluids only, higher cost at larger diameters | Water, wastewater, conductive liquids |
| Coriolis | Direct mass flow, extremely high accuracy (±0.1%) | Very high cost, large pressure drop | Precision batching, high-value fluids |
| Vortex Shedding | No moving parts, good for steam | Requires Reynolds Number >10,000, pressure drop moderate | Steam, clean liquids and gases |
The 405C distinguishes itself from Annubar averaging pitot tubes through its 2D straight-run requirement, which is significantly shorter than the 8–23 diameters required by standard Annubar installations. This makes the 405C the preferred choice for retrofits and space-constrained installations.
Industry Applications
The Emerson Rosemount 405C Compact Conditioning Orifice Plate is suitable for flow measurement across a wide range of industries and applications:
| Industry | Typical Applications |
| Chemical Processing | Process gas flow, chemical feed lines, steam distribution (2–12 inch lines) |
| Oil and Gas | Natural gas measurement, flare gas, vapor recovery, LNG cryogenic measurement |
| Power Generation | Boiler feedwater, combustion air, steam flow, cooling water |
| Water and Wastewater | Treated water distribution, aeration air, chemical dosing (2–12 inch lines) |
| HVAC and District Energy | Chilled water, hot water, steam, condenser water |
| Food and Beverage | Clean liquid ingredients, CIP solution flow, steam |
| Pulp and Paper | Process steam, chemical additive dosing |
| Pharmaceutical | Clean utility flow measurement, WFI (water for injection), purified water |
Frequently Asked Questions
Q: What line sizes are available for the Rosemount 405C?
A: The Rosemount 405C is available in standard line sizes from 2 to 12 inches. These correspond to model designations 405C02 (2 inch), 405C03 (3 inch), 405C04 (4 inch), 405C06 (6 inch), 405C08 (8 inch), 405C10 (10 inch), and 405C12 (12 inch).
Q: What is the straight-run requirement for the 405C?
A: The 405C Compact Conditioning Orifice Plate requires only 2 pipe diameters upstream and 2 pipe diameters downstream from the plate to achieve ±0.5% accuracy.
Q: What is the maximum temperature for the 405C sensor?
A: The Rosemount 405C is rated for process temperatures up to 850°F (454°C) with remote mount transmitter configuration, and up to 450°F (232°C) with direct mount transmitter configuration.
Q: Can the Rosemount 405C be used with dirty or sticky fluids?
A: No. The 405C is not recommended for dirty or sticky fluids, as particulate accumulation can alter the beta ratio over time and degrade measurement accuracy.
Q: What transmitters are compatible with the 405C primary element?
A: Compatible transmitters include the Rosemount 3051S (assembly designated 3051SFC Compact Flowmeter), Rosemount 3051C, Rosemount 2051C, and Rosemount 4088 MultiVariable Transmitter.
Q: Does the Rosemount 405C require conductive fluids?
A: No. Unlike magnetic flow meters such as the Rosemount 8711 and 8721 series, the 405C Compact Conditioning Orifice Plate can measure any clean fluid—conductive or non-conductive.
Q: What is the recommended calibration interval?
A: Under normal operating conditions with clean fluids, calibration intervals of up to 10 years are achievable.
Q: Is the Rosemount 405C available with a centering ring?
A: Yes. The 405C comes standard with a self-centering ring independent of flange rating that ensures proper alignment within the pipeline.
Q: What is the accuracy of the 405C?
A: The 405C Compact Conditioning Orifice Plate delivers ±0.5% of flow rate accuracy when installed according to the specified straight-run requirements.
Q: Can the 405C be used for cryogenic applications?
A: Yes. The remote mount configuration supports process temperatures down to -321°F (-196°C), making it suitable for LNG and other cryogenic gas measurement.
Q: What is the maximum pressure rating for the 405C?
A: The Rosemount 405C is rated to ANSI B16.5 Class 600# (DIN PN100) , with a maximum working pressure of 1,440 psig at 100°F.
Q: Does the 405C require impulse piping?
A: No. The 405C Compact Conditioning Orifice Plate installs directly between raised-face flanges, eliminating the need for impulse piping entirely.
Ordering Information
The Rosemount 405C Compact Conditioning Orifice Plate Primary Element is configured based on line size, beta ratio, process conditions, and transmitter integration requirements. A Configuration Data Sheet must be completed prior to order for application verification and sizing.
Key ordering parameters include:
Line size — 2, 3, 4, 6, 8, 10, or 12 inches (50 to 300 mm)
Beta ratio (β) — 0.40, 0.50, 0.60, or 0.65
Process fluid — Gas, steam, or liquid with complete properties
Operating pressure and temperature — Minimum, normal, maximum
Flow rate range — Minimum, normal, maximum flow rates
Mounting type — Direct mount or remote mount
Flange standard — ANSI B16.5 Class 600# or DIN PN100
Transmitter integration — 3051S (for 3051SFC designation), 3051C, 2051C, 4088 MultiVariable, or customer-supplied
NACE compliance — NACE MR-0175 / ISO 15156 available
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