When you’re looking to set up a weir box for flow rate measurement, you’ll find that many don’t include a baffle plate. While this may be OK in some circumstances, the conditions required to eliminate the need for a baffle plate can be quite rare. Learn about all the benefits of baffle plates, and discover whether you need one for your weir box setup.
One of the most serious problems with weir box measurements stems from issues with surface turbulence. This phenomenon causes the surface of the flow in the weir box to be too wavy to properly take measurements. Common causes of surface turbulence include high flow rates and odd angles that don’t keep the flow straight and centered as it approaches the weir box.
When you apply a baffle plate to your design, you can reduce surface turbulence to ensure accurate measurements. It does this by forcing the water to travel under the plate, which removes many of the factors that cause surface turbulence. Just make sure that any potential surges don’t overtake the baffle plate from the top.
Chemical or biological foams can cause serious problems with flow rate measurements. This is especially true if you’re using ultrasonic flow meters, as the foam makes the meters think the surface of the flow channel is higher than it is, rendering all measurements fundamentally inaccurate.
When you implement a baffle plate in a weir box with surface foam, you can eliminate much of it because it’s stopped upstream of the measurement point and is unable to pass through the baffle plate itself. Given that the flow after the baffle plate is largely calmer, it’s less likely to generate foam again, so you don’t have to worry about any chemical or biological contaminants having the chance to throw off surface measurements after the initial foam is dispersed.
Solids in a flow channel can throw off flow measurements significantly, as they can increase the surface level or make the point of measurement uneven. Depending on the type of measuring you do, the deposit of solids on the floor of the weir can also cause problems for measurements. Additionally, solids can compromise dam seepage monitoring as they get in the way of analyzing the actual health of a dam.
Implementing a baffle plate allows the suspended solids to settle out. Keep in mind that this can be a problem for some weir boxes, as they’ll need to have the solids removed regularly, but for dam seepage monitoring, a common use for weir boxes, it’s essential to ensure accurate measurements of dam health.
Get a Baffle Plate From Tracom
When you’re looking to get your hands on a baffle plate for your weir box, Tracom has got you covered. We can set you up with all the accessories you need for your weir box as well as with experts who can make recommendations and help with installation. Contact us today to get started!