ASME MFC-16-2007 pdf download
ASME MFC-16-2007 pdf download.Measurement of Liquid Flow in Closed Conduits With Electromagnetic Flowmeters.
6.3.1.3 Abrasive Slurries. Excessive wear should be a consideration for increasing the pipe diameter in the measuring section of the piping (i.e., the flowmeter sensor, and the preceding and following piping) to reduce the liquid flow velocity.
NOTE: Exceive liner wear can be caused by an asymmetrical flow profile (see para. 612). improper liner material selection (see pars. 6.5.2), or horizontal installation of the fiowmeier primary
In particular, the upstream edge of the liner may be subject to wear from abrasive slurries. To minimize this upstream edge wear, it is beneficial to match the internal diameter of the flowmeter primary and the near upstream piping. Metal protection rings can also be installed to reduce the wear on the edge of the liner.
Consult the manufacturer for guidance regarding materials of construction and installation experience for applications with abrasive sluthes.
6.3.1.4 Fast-Settling Slurries. Velocities must be sufficient to keep slurry solids in suspension when the meter is mounted horizontally. Furthermore, if solids are prone to settle during no-flow conditions, there must be sufficient velocity to flush the settled materials from the flowmcter primary at startup (see para. 6.4.1.3).
6.3.2 Special Process Considerations, There may be situations where it is desirable to size the flowmeter at other than the pipe size, When this is the case, the process liquid properties and velocity range of the flowmeter must be considered. As a matter of practice, applications utilizing small meters 112 mm (!4 in.) and lessj are more sensitive to pipe mismatch effects than larger meters and should be given special consideration.
6.4 Flowmeter Primary — Location, Installation, and Maintenance
6.4.1 FLowmeter Primary Location and Orientation.
Generally, there are no restrictions on flowmeter primary orientation (horizontal, vertical, or inclined). However, it is essential that the flowmeter primary be full of the process liquid to ensure proper performance.
The performance of electromagnetic flow meters may be influenced by the location and orientation of the flowmeter primary with respect to the process piping. Consequently, paras. 6.4.1.1 through 6.4.1.5 should be considered.
6.4.1.1 Piping Effects. When a flow velocity profile is different from that of profile for the original flow calibration, the electromagnetic flowmeter may exhibit a change in performance. The arrangement and location of pipe fittings, valves, pumps, etc., upstream and downstream of the flowmeter primary, are the main factors that influence the velocity profile. The manufacturer must specify upstream and downstream lengths of straight pipe of the same diameter as the flowmeter primary for proper performance.
Swirling flow can introduce flow measurement errors. When swirling flow is suspected or known to exist, it may be advisable to use a swirl-reducing flow conditioner.
6.4.1.2 Full Pipe Requirements. The flowmeter primary must be installed to assure that it is completely filled with the liquid being metered. For instance, it may be difficult to ensure completely filled conduit in a vertically installed flowmeter with downward flow. If the meter is not lull, the application is beyond the scope of this Standard and the meter performance may have increased uncertainty.
6.4.1.3 Electrode Position — Horizontal Installations. Since gas bubbles in a horizontal pipe tend to rise and may collect at the top of the pipe, the flowmeter primary should be mounted so that no sensing or grounding electrodes are located at or near the top of the pipe. Similarly, since solids in a horizontal pipe tend to settle and collect at the bottom of the pipe, the flow- meter primary should be mounted so that no sensing or grounding electrodes are located at or near the bottom of the pipe.
6.4.1.4 In-Situ Zero Checking. If the flowmeter zero is to be verified in-situ, some meter manufacturers require that the flowmeter primary remain completely filled with stationary liquid.
6.4.1.5 Location with Regard to Electrical Interference. Under many field situations, electrical interference will not affect performance of the flowmeter. However, it is advisable that the meter be installed in an area with minimal radio frequency and electromagnetic “noise,” e.g., away from heavy machinery and/or equipment operating at high voltage or current (see paras. 6.4.3 and 6.7).
6.4.2 Installation of Flowmeter Primary
6.4.2.1 Installation Design. When designing the piping system, access for installation and removal of the flowmeter primary should be provided. Refer to local piping codes and user-specified procedures during construction and installation to minimize the strain on the flowmeter primary. The installation should allow ready access to all mechanical and electrical connections.
