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『Blue White Flow Meter Review: Variable Area Meters for Chemical Feed』Related information(flow rotameter|digital flow meter|balo meter|hydraulic flow meter|volumetric meter|positive displacement meter|pitot tube flow meter|displacement meter|cfm meter|variable area flow meter|inline flow meter|differential pressure flow meter|calibrated flow meter|velocity meter|paddle wheel flow meter|oval gear flow meter|anemometer hvac|multiphase flow meter|doppler flow meter|thorpe tube flowmeter|heat flow meter)
Blue White Flow Meter Review: Variable Area Meters for Chemical Feed
Quick Answer: Blue White variable area flow meters (rotameters) reliably handle clear chemical feed such as sodium hypochlorite, citric acid, and polymer for water and wastewater dosing. These plastic tube meters keep the cost low for simple installations at ambient temperature. When the chemical is hot, opaque, or sticky, a metal tube rotameter from Silver Instruments gives you longer service life and optional 4-20 mA output.
Why Engineers Pick Blue White for Chemical Dosing
Blue White flow meters use a tapered tube and a float that rises with flow. The direct reading scale lets operators check the chemical feed rate at a glance. No external power is needed. Common sizes for dosing are DN10 to DN25 with PVC, polysulfone, or acrylic bodies. Many water treatment plants in Australia and Thailand install them after a metering pump to verify the daily hypochlorite dosage.
Where Blue White Meters Work Well
You will see them on chlorine dosing in village water systems, cooling tower biocide injection, and CIP chemical feed in food plants. The meters handle water-like viscosities up to about 50 cP. With clean liquids and a steady back pressure of at least 0.5 bar, the reading stays stable. The float material matters: a stainless steel float works for most chemicals, while a PTFE float suits aggressive acids.
What Engineers Often Miss
In practice, many installations suffer from pulsating flow because the dosing pump is a diaphragm type. The float bounces and the reading becomes useless. A pulse dampener or a constant-head tank solves this. Also, if the pipe is not vertical, the meter loses accuracy. Plastic models start to crack when the fluid temperature stays above 50 °C for long periods. We have seen cracked polysulfone tubes at a customer site in Vietnam after only four months with hot rinse water.
When to Choose a Metal Tube Rotameter Instead
If your chemical feed stream is above 60 °C or contains suspended solids, a plastic variable area meter is not the right answer. Opaque fluids make the float invisible. In these cases, Silver Instruments supplies all-metal rotameters with magnetic coupling and analog or HART output. The metal design works for diesel, hot CIP s
FAQ: Blue White Flow Meters in Chemical Service
Can I use a Blue White flow meter for sulfuric acid?
Yes, but only at low concentrations (below 30 percent) and with the correct float and O-ring material. Check the chemical compatibility chart from the manufacturer. For higher concentrations, a PTFE-lined metal rotameter from Silver Instruments is a safer choice.
Does the meter work with pulsating flow from a peristaltic pump?
The float will oscillate. A simple pulse dampener or a length of flexible tubing before the meter can reduce the pulsation. If you need stable readings all the time, consider a Coriolis mass flow meter from Silver Instruments with no straight run or dampener needed.
What is the typical accuracy of a Blue White rotameter?
Around plus or minus 5 percent of full scale under steady flow. This is enough for chemical feed verification but not for custody transfer. For billing applications, an oval gear flow meter gives 0.5 percent accuracy or better.
Can I install the meter outdoors?
Sunlight will degrade the plastic tube over time and UV stabilizers delay this but do not stop it. A simple sunshade adds years of life. If the environment is harsh, switch to a metal rotameter with a sealed indicator.
How do I size the meter for chemical feed?
Provide the flow range in liters per hour, fluid density in kg per liter, viscosity in cP, and operating temperature. Send these four numbers to Silver Instruments at [email protected] and the team sizes the right meter for you, whether it is a Blue White model or a metal alternative.
Get a second opinion on your chemical feed meter. Send your pressure (bar), temperature (°C), pipe size (DN), and flow range to [email protected]. You can also reach us by phone at +86-135-1213-1526, WhatsApp at 86-135-12131526, or WeChat at +86 13512131526. Our engineers compare plastic and metal rotameters every day for customers in Southeast Asia, Oceania, Latin America, and the Middle East.