Liquefied chlorine gas is drawn off as vapour, and the latent heat of vaporisation is pulled from the liquid and the container wall — so the container cools as you draw. Dependable continuous withdrawal is limited by how fast room air can put that heat back.

Set your container type, room temperature and how many containers run at once. The tool tells you the dependable withdrawal rate, whether your duty containers cover the design feed, and how much chlorine you are holding on site. Frost on a container marks where the wall has reached the air dew/frost point — the chlorine itself is not frozen (Cl₂ freezes at −102 °C).

The withdrawal-rate model (rated rate, temperature sensitivity, cut-off) is in Settings so you can tune it to your supplier's data.

Vacuum gas dosing in three parts: a vacuum regulator on the container holds the line under vacuum, a variable-area rotameter (with a V-notch metering orifice) sets the gas rate, and an ejector uses motive water to entrain the gas into solution. The ejector's vacuum is what pulls gas through the whole train.

This tab sizes the rotameter full scale for your design feed, checks the turndown reaches your minimum feed, works out the minimum motive water for the ejector, and confirms the ejector has enough net operating pressure. Design limits (rotameter band, maximum solution strength, minimum net pressure) are in Settings.

Sodium hypochlorite slowly decomposes two ways at once: to chlorate (3 OCl⁻ → ClO₃⁻ + 2 Cl⁻) and to oxygen (2 OCl⁻ → 2 Cl⁻ + O₂). Available-chlorine loss is roughly second-order in strength, so stronger product decays faster, and the rate is strongly temperature-driven — roughly doubling every ~5 °C.

Enter your delivered strength, density, storage temperature and how long you hold product. The tool shows the strength and chlorate you can expect at the end of that period, the half-life, and how it all shifts with temperature. Because real decay depends heavily on trace metals and stabiliser, the rate constants are tunable in Settings, which also has a one-click calibration to back-solve them from a measured decay point.

As hypochlorite decomposes by the oxygen route it releases O₂. Those bubbles collect in suction lines and pump heads and break the prime of diaphragm metering pumps — "vapour lock". This tab estimates the off-gas rate and suggests a vent size, then sizes the metering pump.

The key sizing move: because product weakens with age, the pump is sized on the weakest (aged) strength so it can still deliver the dose, and we check the fresh-strength rate stays within turndown. The checklist below covers flooded suction, degassing heads and the other practical steps that keep a hypochlorite pump primed, and the vapour corrosion every hypochlorite plant room needs designed out.

A serpentine baffled contact tank gets closer to ideal plug flow as its flow-path length-to-width ratio rises. The baffling factor BF = t₁₀/T (the 10th-percentile residence time over the theoretical) is the fraction of contact time you can credit, and C.t credit = FACE × t₁₀. FACE (free available chlorine equivalent) equals the free chlorine below pH 8.00; at pH 8.00 and above it is lowered in proportion to the hypochlorous acid present (pKa taken at 10 °C). The Giardia and virus log credits use free chlorine × t₁₀, because the USEPA requirement already allows for pH.

Enter the tank geometry, the free chlorine residual, temperature and pH, and your target Giardia and virus log credits. The tool returns the volume, theoretical and credited contact time, the CT achieved versus what's required, and the log removal you actually earn. The aim is to push BF toward 1 with high L:W, good inlet distribution and an outlet weir — then confirm the credited BF by a tracer test.

Everything you need to take your work away lives here — and only here. Choose which tabs to include, then export a clean PDF report, download the inputs and results as CSV, or save the whole session as a JSON file you can reload later.

Tip for the PDF: in your browser's print dialog turn Headers and footers off for the cleanest result. The report is laid out to keep result blocks together across page breaks and shows every value as text.