Open Channel Flow


	81 BLEACHERY COURT WARWICK RI USA 02886 401-463-9199 The Leader in Reliable Flow Measurement

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Open Channel Flow Measurement
If the EPA or other authorities
question your wastewater
discharge measurement,
PRIMARY FLOW SIGNAL, INC.
has the answer!

THE HALMI-PARSHALL FLUME WAS SPECIFICALLY DEVELOPED TO SUIT SUCH NEEDS, WITH:

+/- 2% ACCURACY (+/-0.75% with Flow Calibration) ACCURACY TRACEABLE (to NIST formerly NBS) LOW HEADLOSS ADJUSTABLE LAYING LENGTH FOR ANY PIPE LINE SIZE REMOVABLE RESTRICTORS provide adjustable flow meter capacity REMOVABLE RESTRICTORS			ACCURACY CAN BE VERIFIED visually in the field PFS DESIGN SERVICE WILL properly locate the meter METER CAN BE BUILT OF ANY MATERIAL required by the specific application ANY SIGNAL SENSOR CAN BE USED INCLUDING: C/R Probe; Staff Gauge; Ultrasonic Level Measurement; Float Well; Pressure Transmitter; SPECIAL PATENTED design US Patent No: 4671119
THE Halmi- Parshall METERING PRINCIPLE LEAVES NO QUESTION UNANSWERED!

Have you ever specified or used Parshall Flumes in the “Pipe-to-Box-to-Flume-to- Box-to-Pipe” way shown here?
		Have you ever considered the errors this design introduced? Flow calibrations performed at the Alden Research Laboratory reveal that the customary “pipe-to-box-to-flume-to-box-to-pipe” design introduces the flow metering errors shown to the left (of this paragraphs) and greater ones, depending on the geometry of the metering section. Halmi-Parshall Flume meters eliminate these errors.
Additional advantages of the PFS-Halmi-Parshall Flume design are: - Lower Headloss - Shorter laying length - Maintains accuracy regardless of line size. - Accepts different inlet and outlet pipe diameters without accuracy deterioration. - Adjustable capacity using removable restrictors.
The Main Difference lies in the INSTALLATION DESIGN SERVICE Which is part of the metering package supplied by PFS, Inc.
The importance of this service is underscored by the fact that the placement of a flume in the pipe line and the geometry and slope of the upstream and downstream piping play an important role in securing accurate flow measurement. This kind of design service is unavailable from the “pipe-to-box-to-flume-to-box-to-pipe” design manufacturers. When these manufacturers are approached with placement questions, they disclaim responsibility for the accuracy of the installed meter. Instead, they refer customers to standard published Parshall flume literature, implying that the flumes described therein are identical to those they are selling. This implication is far from the truth, as proved by the errors uncovered through PFS, Inc. research work (see PFS Publication No: 820-A.) In contrast, PFS, inc. takes full responsibility for the PFS-HF and PFS-HN design.

DIMENSIONS - CAPACITIES - INSTALLATION

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Please send comments, questions, or suggestions about our services to Dezi G. Halmi at dezi@primaryflowsignal.com
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Copyright 2001 by PFS, Inc	Web Services by Primary Flow Signal, Inc. Last Modified 17 May 1999