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Fixed Weir Plates are common and simple methods of measuring the flow of water in open channels. At its simplest, a weir is no more than an obstruction placed in a channel over which water flows (unlike flumes where the water flows through the structure). Often this flow is over a specially shaped notch or opening set above the floor of the channel.
Properly size, built, and maintained, a weir can provide inexpensive and accurate flow measurements.
Openchannelflow fixed weir plates can be designed to either span the full channel or be bolted to a bulkhead or other structure spanning the channel.
All Openchannelflow fixed weir plates conform to ISO/DIS 1438 Hydrometry – Open Channel Flow Measurement Using Thin-Plate Weirs in their sizing and application.
Weir Materials:
Weir plates - or at least the crest - should be constructed from T-304 stainless steel. Other materials are prone to loose dimensional tolerances, swelling, and are susceptible to crest damage.
If the weir plate does not span the channel and is bolted or secured to a bulkhead or other structure, it's not required that the strucure be constructed from stainless steel - only that it be perpendicular to the flow stream and watertight. The weir plate itself, though, should be stainless steel.
Portable Weir Plate Sets are a simple way to measure water in natural channels. Each set consists of (4) interchangeable stainless steel weir plates and an aluminum weir carrier. With interchangeable plates, you can select the weir that best fits each site's flow rates. Precision manufacturing ensures the weir plates are interchangeable and field replaceable. The weir plate conforms to ISO/DIS 1438 Hydrometry – Open Channel Flow Measurement Using Thin-Plate Weirs for their dimensions and flow rates.
Properly size, built, and maintained, a weir can provide inexpensive and accurate flow measurements.
Weir Materials:
The (4) interchangeable weir plates are:
A Weir Box incorporates a thin-plate weir (V-notch or Cipolletti) into a pre-engineered structure. Weir Boxes are generally used to measure from 3.990 – 493.5 gpm [0.2518 – 31.14 l/s] - although larger flow rate Weir Boxes are available.
Openchannelflow Weir Boxes conform to ISO/DIS 1438 Hydrometry – Open Channel Flow Measurement Using Thin-Plate Weirs, are extremely versatile, and can be configured for either above ground or shallow burial installations, and are commonly used to measure dam seepage and treated industrial discharges.
Flows entering / exiting the Weir Box can be piped, or it can be free spilling. The Weir Box design's inherent design flexibility means that multiple inlet / outlet flow streams can be accommodated as well as dual (or triple) flow streams measured independently.
Each Openchannelflow Weir Box consists of:
The Weir Box body is specifically sized to generate the proper weir pool for the intended flow rate – something lacking in most competing weir boxes.
To help secure the Weir Box, each unit is provided with stainless steel anchor feet on the outside of the box, allowing it to be mounted to a concrete slab.
Weir Channels by Openchannelflow offer a drop-in-place solution to the problem of measuring flows in creeks, small streams, canals, and channels.
We’ve taken our experience with weir boxes / weir plates and combined it with the ease of installation of our Packaged Fiberglass Weir Manholes to create a product that is unique in the marketplace. By integrating our field removable/replaceable ISO/DIS 1438:2008 compliant sharp-crested, thin-plate weirs, with pre-engineered channels, Openchannelflow Weir Channels provide not only accurate flow measurement, but also operator safety, convenience, customization, and ease-of-use/installation.
Installation can be accomplished with either traditional anchor clips secured to earth anchors or the Weir Channel can be secured off-site to a pre-cast concrete slab for a true, no-hassle installation.
Weir Channel options
With Weir Channels from Openchannelflow, you get accurate flow measurement in an operator-friendly and easy to install factory-integrated package.
Staff gauges (aka head or level gauges) are a convenient way to determine liquid level without the need for instrumentation or operator effort.
Depending upon your application needs, Openchannelflow offers three gauge configurations:
Openchannelflow gauges are available in single scale (e.g. feet) or dual scale layouts (e.g. cm and l/s). Dual scale gauges can indicate not only level, but also additional information (typically flow).
Depending upon the application / width of the gauge / scale type, markings can be 1/2” to 6” [1.27 to 15.24 cm] H - with larger markings suitable for applications where the viewing distance is large (tide level, river stage, tank levels, etc.)