Correct Upstream Conditions For Parshall Flumes

When it comes to open channel flow management, there is almost no primary device better than the Parshall flume. Suitable for a wide range of applications and understood by flow management operators throughout the world, a Parshall flume is the top choice if you want to accurately measure the flow in your system.

If you want to get the most out of your Parshall flume, you need to make sure your device is installed correctly, and this includes creating the right upstream conditions. Here are a few tips to help you create the correct Parshall flume upstream conditions so your primary device functions properly.

Make the Flow Tranquil

The most important part of creating the right Parshall flume upstream conditions is making sure the flow entering your flume is tranquil. Basically, this means there should be no turbulent conditions, particularly surface waves.

To make sure your flow is tranquil, the upstream channel leading into your flume should be completely straight. The channel should have no curves or turns that could potentially increase turbulence. Although this can be difficult to achieve when installing in a natural channel, keeping the channel upstream of your flume straight is key if you want your device to function the right way.

Keep a Sub-Critical Velocity

The primary function of a Parshall flume is accelerating the flow in a system to a super-critical velocity, which allows for a single point of measurement within the flume. For your flume to serve this purpose, however, your flow must be at a sub-critical velocity as it enters the device.

If the velocity of the low entering your flume is too fast, your flume won’t function correctly and your readings will be inaccurate. To make sure your flow is sub-critical as it enters your flume, your upstream channel should be level, meaning there are no sudden drops in elevations that could speed up the flow. If maintaining these conditions are not possible, you could add an energy absorber to your system to remove excess velocity from the flow.

Natural Channel Consideration

If you’re installing your Parshall flume in a natural channel, there are a few factors you should take into account that aren’t necessary for industrial applications. For starters, you need to be sure the upstream banks in the natural channel are clear of vegetation, which may impact the approach velocity of your flow. Periodically, you should have your operators examine the channel and clear any growth or other blockages.

Adding wing walls to your flume may also be necessary when installing in a natural channel. Wing walls will direct flow into your flume and prevent flow bypass, making it easier to take accurate readings.

Invest in a Parshall Flume

Now that you know how to create the proper Parshall flume upstream conditions, you should be ready to install this versatile device in your system. If you need to purchase a Parshall flume, you can work with the team at Tracom, FRP. In our inventory, you’ll find top-notch fiberglass flumes that will more than meet your needs, including the reliable Parshall flume. Request a quote from Tracom today so you can get started installing your flow management device in your system.

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