When you use a flume or weir for flow rate measurement, a lot can go wrong. One of the most troublesome issues you may run across is a buildup of foam. Foams come in several different forms, and they all can throw off your measurements, rendering the whole effort useless. Learn about the basics of foams, and discover what you can do to avoid them.
The Problem With Foam
Foam doesn’t exactly look pretty, but aesthetics aren’t really much of a problem when it comes to flow rate measurements. Not being able to take accurate measurements, however, is a serious problem that warrants immediate solutions. Unfortunately, that’s the exact problem that foam buildup can cause.
Foams are especially troublesome when you use ultrasonic flow meters. Because the foam alters the point that the meter registers as the surface of the flow, you’ll get unreliable readings. You can change the kind of meter you use to account for foam, but that’s not always easy or even feasible.
Types of Foams
Foams come in two primary forms. The first are known as chemical foams. These are what most people imagine when they think of foams, as they are fluffy and white, and they collapse easily when touched. Fortunately, these particular kinds of foams are also quite easy to address. All you need are chemical defoaming agents to feed into your flow channel. These can not only get rid of any foam that has developed but also prevent more foam from forming.
The other type of foam is biological foam. With this particular brand of nuisance, you’ll find foam that looks to be more brownish in color along with a sticky and slimy surface. Typically, this foam forms as a result of fat, oil, and/or grease buildup, though hydrocarbons can also cause it. Defoaming agents don’t do much to combat this kind of foam, so you’ll have to implement other strategies to deal with it.
To reduce the impact of foams on your flumes and weirs, there are a few actions you can take. One of the most effective is implementing a stilling well. Attaching these chambers to your device will draw a portion of your flow to the side. By doing so and ensuring that the flow covers the well’s inlet, you can reduce and potentially eliminate foam buildup. While this is mainly used for biological foams, you can also handle chemical foams more easily because the well is a good spot for defoaming agents.
Another option you can implement to deal with foam is installing underflow baffles. These are vertical plates that stretch from above the surface to the floor of your device. Foam will get trapped behind these baffles, and the conditioning they cause makes it more difficult for foam to form past the baffle. Just make sure the baffle stretches up high enough to block the foam from getting through.
Accessories From Tracom
Now that you’re prepared to fight the basics of foams, you’ll need a convenient source for those helpful wastewater products and flume accessories
. That’s where Tracom can help. Contact our team today!