The Rosemount 3418 is engineered for the most sophisticated fiscal measurement users. By combining two interlocked 4-path British Gas design meters into a single body, the 3418 creates a mirror-image chordal layout. This patented configuration allows the meter to automatically cancel out the effects of swirl and cross-flow, achieving an OIML Accuracy Class 0.5 rating. Even in challenging piping layouts, the 3418 maintains its ±0.1% accuracy across the entire flow range.
One of the standout advantages of the Rosemount 3418 is its ability to operate with only five diameters (5D) of straight pipe run and no flow conditioner. This significantly reduces compression and pumping costs while eliminating maintenance issues related to conditioner blockages. With a high rangeability of >100:1, facilities can use fewer meter runs and smaller line sizes, drastically lowering overall capital expenditure (CAPEX).
| Feature | Specification Details |
| Line Sizes | DN250 to DN1050 (10-in to 42-in) |
| Accuracy | ±0.1% of reading over calibration range |
| Repeatability | ±0.05% of reading (1.5 to 30.5 m/s) |
| Path Configuration | Eight-Path (Dual Interlocked British Gas Design) |
| Straight Run | 5D Upstream / 3D Downstream (No Conditioner Required) |
| Pressure Range | Up to 27,579 kPag (4,000 psig) |
| Transducers | T-200 Titanium Encapsulated (Extractable under pressure) |
| Rangeability | >100:1 Turndown |
The Rosemount 3418 is the preferred choice for major natural gas headers and gate stations where space is limited but accuracy is paramount. Because the mirror-path design handles asymmetrical flow so well, it is ideal for installations directly after elbows or headers. For corrosive or high-pressure environments, always specify the T-200 Transducers. If your facility also requires high-redundancy for gas verification, the [Rosemount 3417 4+4 Dual-Configuration] is a viable alternative, though the 3418 offers superior swirl cancellation in a single system.
The 3418’s requirement for only 5D of straight run without a conditioner is a "game-changer" for station design. During installation, ensure the 3410 Series Electronics are configured to utilize the Smart Meter Verification feature. This allows the meter to act as a redundant flow computer, calculating corrected volume, mass, and energy rates directly. For sites requiring auxiliary wireless monitoring, the [Rosemount 3051S Wireless] can be integrated to provide real-time pressure and temperature data without trenching.
With no moving parts and no flow conditioner to clean, the 3418 is virtually maintenance-free. If transducer inspection is required, the T-200 series can be safely extracted under pressure (up to 42"), meaning zero process downtime. We recommend using MeterLink™ Software to monitor the archive data logs, which store critical gas composition and composition information. For plants handling heavy liquids or slurries in other areas, the [Rosemount 9195 Wedge Flow Meter] provides a robust, wear-resistant complement to your ultrasonic fleet.
Q: Why does the Rosemount 3418 not require a flow conditioner for fiscal measurement?
A: The Rosemount 3418 features a unique 8-path configuration where the second set of chords is a mirror image of the first. This interlocked design allows the meter to mathematically cancel out flow disturbances like swirl and cross-flow, enabling it to meet OIML Class 0.5 accuracy with just 5 diameters of straight pipe and no flow conditioner.
Q: How does the Rosemount 3418 help reduce operational costs (OPEX)?
A: By eliminating the need for a flow conditioner, the 3418 removes the permanent pressure drop and potential for blockages associated with those devices. This reduces the energy required for gas compression and pumping, while significantly cutting down on long-term maintenance costs.
Q: Can the transducers be serviced while the gas pipeline remains live?
A: Yes. The titanium-encapsulated T-200 transducers are specifically designed to be safely extractable under pressure without the need for special tools. This allows for routine maintenance or sensor replacement without blowing down the pipeline or interrupting the process.
