UV-700 Ultraviolet Sterilizer Sizing — Winston Water Engineering

UV-700Ultraviolet Sterilizer Sizing

UV does not remove anything. It scrambles the DNA of what passes through, so the organism can no longer reproduce. What matters is the dose each organism actually receives — and the ones that take the fastest path receive the least.

Cutaway — Ultraviolet Sterilizer Sizing

WaterDisinfected

How it works

Dose, not contact — UV is measured in millijoules per square centimetre — intensity multiplied by the time an organism spends in the field. A big lamp with a fast flow can deliver less dose than a small lamp with a slow one.
Transmittance — Water absorbs UV. UVT is how much survives one centimetre of path, and it falls fast with organics, iron and colour. Drop UVT from 92 to 75 % and the intensity in the outer annulus collapses — the reactor has not changed, but the dose has.
The fastest path — Not every organism gets the average dose. The one that takes the shortest, fastest streamline gets the least, and that is the organism that sets your log removal. Validated reactors are certified on the worst path, not the mean.
Ageing and fouling — Lamps lose output over their life and the quartz sleeve fouls. Design for end-of-life output, typically 70–80 % of new, or the plant will fail its dose target long before anyone replaces a lamp.
What governs it — Dose is intensity times time; intensity depends on lamp power, geometry and UVT; time depends on flow. Drag UVT down and watch the log removal fall away with no change to the hardware — upstream filtration is part of the UV design.
Low-pressure amalgam — Nearly all the electrical input comes out at 254 nm, right on the peak of DNA absorption, so about 35 per cent of the wattage becomes useful UVC. Nothing else here comes close, and a 16 000 hour lamp life means one change a year. This is why drinking water is disinfected with low pressure, and why the alternatives need a specific reason.

Design parameters

The panel opposite runs the same correlations as the UV-700 design sheet, so the animation and the calculator cannot disagree. Every parameter below is live — drag one and the picture responds.

Parameter	Unit	Default	Range
Lamp technology
Lamp type		LP amalgam	3 options
Wall-plug UVC efficiency differs by a factor of five across these three. It changes nothing about the dose — it changes what the dose costs.
Duty
Flow	m³/h	60	5 – 400
UV transmittance	% / cm	92	55 – 99
Lamp UV output	W each	85	15 – 400
Lamps	off	4	1 – 24
Reactor volume	L	90	10 – 800
Lamp age / fouling factor	–	0.75	0.4 – 1

Open the full UV-700 design sheet for the other five inputs, all twenty-eight results with their envelopes, the five equations printed beside the numbers they produce, and a calculation record you can export and put in a design file.

Live parameters

Six of the eleven inputs the UV-700 design sheet takes.

Lamp technology

Lamp type

Wall-plug UVC efficiency differs by a factor of five across these three. It changes nothing about the dose — it changes what the dose costs.

Duty

Flow 60 m³/h

UV transmittance 92 % / cm

Lamp UV output 85 W each

Lamps 4 off

Reactor volume 90 L

Lamp age / fouling factor 0.75 –

You have an estimate. The design sheet is the justification.

This page sizes the unit on six variables and tells you whether the headline numbers land in range. That is enough to sketch with, and it stays free. What it will not do is survive a design review: it does not show you the equation behind any number, it checks the obvious limits rather than all of them, and there is nothing to file.

The UV-700 design sheet runs the same physics on eleven inputs, reports twenty-eight results against their envelopes, prints the five governing equations beside the numbers they produce, and exports the lot as a calculation record for the design file.