The Foxcroft Blog

1 min read

Foxcroft Solution For Analyzer Flow Blockage

By Ray Sullivan on Fri, May 20, 2011 @ 09:39 AM

 rotometer stops air binding4 resized 600Occasionally we encounter flow reduction or blockage in chlorine analyzers monitoring certain groundwater sources.

We examined this problem at a well station in our area that chlorinates and monitors ground water. The water drawn from the sample tap, unlike aerated "white water", was initially clear with some microbubbles of dissolved oxygen or gases.

These microbubbles decompressed and expanded into clusters of larger bubbles to restrict the orifice in the analyzer flow cell. The blockage would trigger a low chlorine alarm and require extra attention from the operators to remain in compliance.

In our research we found that bubble traps or bubble eliminators can provide mixed results in some applications; so we decided to  prevent bubbles from developing within the analyzer.

Our FX-1000P Rotometer keeps the sample pressurized through the flow cell orifice until it reaches the measuring cell. Since the residual is determined almost instantly, the sample overflows to waste before bubbles have time to enlarge and cause problems. 

The controlled flow also eliminates the need to recalibrate due to flow rate changes, which simplifies consistent, accurate chlorine residual measurement. It's easy to install and includes a pressure regulator with gauge.


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2 min read

5 Reasons Why Vinegar is Good For Your Chlorine Analyzer And You

By Ray Sullivan on Mon, May 09, 2011 @ 10:21 AM

Non-toxic eco-friendly pH bufferSo why does our model FX-CLv2 residual chlorine analyzer use ordinary distilled white vinegar and what does it mean for you?

1. It Optimizes Chlorine Residual Readings 

A true on-line, amperometric, chlorine residual analyzer requires a pH buffer to bring the sample pH down to a range where optimum free chlorine residuals can be accurately measured, ideally 4.0 to 4.5 pH.

Any amperometric chlorine residual analyzer that claims buffers are not required uses either a pH buffered electrolyte in the  probe, or makes an electronically simulated pH compensation (which is not a true chlorine residual reading).

The vinegar reduces the pH in the sampling cell, which provides the current potential needed to measure chlorine residuals accurately. Through dissociation, chlorine will be in the measurable form of   hypochlorous acid rather than in its ionic state that can't be measured.

2. DPD Is Toxic, Vinegar Is Better For Our Water & Your Budget

Toxic DPD discharged to waste from one colorimetric chlorine analyzer may not seem like much; until we consider the thousands of colorimeters in service throughout the country.

The impact of toxic DPD discharge is being examined. Minimizing the use of toxic reagents could become even more important as water reuse and recycling increases.

Our contribution is to use a buffer solution, or reagent, that we all consume regularly in various foods. Distilled white vinegar is a food product, and as such doesn't require special haz mat permits or disposal, which is good for your budget and our environment.

3. Do The Math, It's Less Costly

Some chlorine analyzers require expensive, proprietary pH buffer solutions or reagents. In most parts of the country distilled white vinegar costs less than $2.50 per gallon. This means the monthly  reagent cost for an FX-1000P measuring free chlorine is roughly the same price as a large pizza with extra toppings.

4. Cleanliness Is Next To Godliness

This proverb traditionally refers to personal hygiene, but it also applies to the measuring cell of our chlorine analyzer. The vinegar enhances the action of the cleaning balls in the measuring cell. It works to dissolve grease, iron, manganese, dirt and other solids. Cleanliness provides more accurate readings. It also prevents the electrodes from becoming insulated by precipitates or contaminants.

5. In A Pinch It's Readily Available

It seems like things usually break or run out after normal business hours. If your Foxcroft chlorine analyzer runs out of buffer solution at 8 PM Friday night you don't need to take grab samples over the weekend. You can pick up more "buffer solution" at a 24 hour grocery store, convenience store, or in a pinch, from your own kitchen.

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