How They Make It Work – Emerson’s Rosemount 9195 Wedge Flow Meter
Company:
Emerson
Technology:
A wedge primary element is designed for measuring fluid flow of process media in pipelines, ideal for highly viscous or abrasive fluids. The wedge element, welded into a pipe spool, creates a pressure differential that is measured by pressure taps on either side of the element. Through impulse tubing or remote seals, a transmitter reads the differential pressure and calculates a flow rate.
The wedge shape creates a gradual constriction, minimizing flow disruptions by allowing vicious fluids to pass by smoothly. Additionally, the element is abrasion resistant because its design promotes a shallow approach angle of the process media, and due to its absence of critical sharp edges.
Significance in chemical operations:
Chemical plants can have many measurement points across the site. Simple fluids — such as air, gas and water — are relatively simple to measure utilizing different flow technologies.
However, unique fluids — like some petrochemicals, synthetics or fertilizers — are harder to measure due to their high viscosities. These fluids can impede the rotors of a turbine meter, not generate the required vortices in a vortex meter or introduce a massive pressure drop in a Coriolis meter.
A wedge meter provides a solution for these applications with its design, including remote seal taps to reduce maintenance time by measuring differential pressure without the need to constantly clean impulse tubing.
Unique features
- Triangle shaped design is resistant to wear, lacking sharp edges that would wear over time
- Fully integrated design allows for simpler installation
Remote seal packages use curated seal options to address a variety of application types. - Saddle-style remote seal connection reduces the weight of the meter by 50%, and it reduces the required pipe standoff to address plugging and cleaning concerns
- Flanged model uses a 2-in. NPS/DN50 connection, a traditional style used if flushing rings and valves are required
- The threaded model uses a ½-in. NPT connection with tubing, ideal where plugging is less of a concern than erosion or wear
Case study:
A Texas chemical plant needed a measurement technology to handle its highly viscous catalyst flow. A prime requirement for the site was to alert and measure any reverse flow that occurred and to reduce overall maintenance required to clean out impulse lines.
Specified with 2-in. NPS flanged connections and Rosemount 1199 remote seals, the chemical plant was able to minimize plugging concerns and maximize uptime. The symmetrical wedge shape, combined with a Rosemount 3051S DP flow transmitter, allowed the plant to measure bi-directional flow based on the transmitter’s mA output.
