Flume Manufacturers: Comparing Parshall Flumes

When we talk of “or equal” what exactly does that mean when we are talking about fiberglass Parshall flumes?

To some, a Parshall flume is a Parshall flume, with little if any distinction made between manufacturers. Naturally we don't feel the same. We take an inordinate amount of pride in the product that we put out the door and what to make sure that you are fully informed as to the difference that can occur in even a "standard" flume like the Parshall.

Before we do that, though, let's get familiar with the Parshall flume.

Parshall Flume Background

The Parshall flume dates back to the groundbreaking work of Dr. Ralph L. Parshall in the 1920’s. Over the years it has come to span 22 standard sizes, from 1” to 50’, covering flow rates from 0.0033 CFS to 186.88 CFS. The Parshall flume is the most widely used style of flume in North America.

For wastewater and industrial pre-treatment discharges, Parshall flumes are constructed in fiberglass due to its superior strength and corrosion resistance. Less demanding applications, such as water rights monitoring, typically require only galvanized steel construction. Occassionally, applications will require resistance to extremes of temperature, corrosion, or abrasion. There stainless steel is the material of choice.

The Comparison

As with our other comparison articles on manufacturers of H Flumes and Packaged Metering Manholes, both sets of photos are from production flumes shipped to end-users. Neither unit is a “show” model prettied up for the occasion.

For complete disclosure, we had intended to compare 1” Parshall flumes, but had to settle on a 2” Parshall flume for comparison purposes. Apparently Kenco Plastics find it too hard to keep the dimension tolerances on a 1” Parshall – their words not ours – and only offer the 2” size and above.

Now unlike the other articles in this series, you will find more commentary on what you see. You'll understand as you look through the photos below.

Parshall Side View

Side Detail on Kenco Plastics Fiberglass 2" Parshall Flume

Side View of an Openchannelflow Fiberglass 2" Parshall Flume

Fiberglass Thickness

Fiberglass Laminate Thickness on a Kenco Plastics 2" Parshall Flume

Uniform Laminate Thickness on an Openchannelflow 2" Parshall Flume - Strick Quality Control is Apparent

Trimming

Finishing Details on Kenco Plastics Parshall Flume - Who Said Free Hand Trimming Was a Lost Art?

Finishing Details on Openchanneflow Parshall Flume

Summary

Now we know the above doesn't seem like a fair comparison, it isn't...and isn't intended to be. What you see are production flumes from both manufacturers. While the Openchannelflow flume will cost more than the "similar" Kenco flume, are they really equal?

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