Thin plate weirs are one of the most popular primary devices for operations that need to measure flow. A thin plate weir provides a great deal of versatility and accuracy, particularly when you are using your weir in outdoor applications. However, like every flow measuring device, there are certain limits to how you can use your thin plate weir, and learning about these limitations is a good idea before installing this device in your system.
Here are a few limitations of thin plate weirs that you should know about if you’re considering using this device in your operation.
Sizing the Weir Pool
There are a few requirements you will need to meet before installing your thin plate weir, including forming a weir pool. A thin plate weir cannot measure flow unless there is an upstream pool. This pool works to condition the flow before it enters the weir, and must possess certain dimensions, including side contractions and a deep enough bottom.
If you’ve never installed a thin plate weir before, then you might be surprised at just how large your weir pool needs to be to function properly. For example, the channel that connects your weir pool to your weir needs to be between 15 and 20 feet, which can be difficult depending on where you’re installing your weir plate.
If you’re like many flow measurement operations, then one of your main goals in choosing a flow measuring device is probably simplicity. You want a device that can effectively measure flow and needs little to no attention from your operators. A big limitation of using a thin plate weir is the need for continuing maintenance to ensure its accuracy.
Because the weir pool slows the velocity of your flow before entering the weir, sediment frequently builds up in your weir pool. At a certain point, this sediment will impede the flow in your system and affect your success. To ensure your weir plate works the way you need, your operators will need to periodically remove sediment from your weir pool.
Similarly, your weir plate can only accurately measure the flow in your system if the weir crest is maintained properly. Over time, the weir crest of your weir can experience different forms of damage, including abrasions, nicks, and rounding. These imperfections can alter the way that flow spills over the weir crest and reduce the accuracy of your readings. Your operators will need to frequently check your weir crest for damage and address any issues that may affect the integrity of the crest.
A Thin Plate Weir is Still a Great Choice
As you can see, thin plate weirs have several limitations that may not make them the best choice for every flow measurement application. However, as long as you keep these limitations in mind, you can safely install a weir plate in your system and get the accurate readings you need. If you want to use a thin plate weir for your operation, the best solution is purchasing your weir from Tracom, FRP.
Tracom offers weirs, flumes, and other water management products, and can help your operation purchase the right tools. Contact us today.