Some UV lamps are used not for room or water disinfection, but as part of analytical equipment.
One pharmaceutical plant used Mettler Toledo M300 and TOC 4000 systems for monitoring organic contamination in process water. When the original UV lamps reached the end of their service life, the plant needed compatible replacements without modifying the analyzers themselves.
The task looked simple, but there were several practical constraints.
Why the lamp mattered
TOC analyzers rely on a stable UV source as part of the measurement process.
For replacement, the new lamp had to match the existing system in several ways:
overall dimensions;
electrical characteristics;
operating mode;
mounting geometry;
UV output;
compatibility with the existing housing.
A lamp with approximately the same power would not necessarily work if its dimensions or electrical behavior differed from the original.
The original lamps were no longer easy to source
The plant needed 24 replacement lamps.
The original components were no longer readily available, while the equipment itself remained in operation and did not need replacement.
This created two separate tasks:
find a technically compatible lamp;
organize the supply quickly enough to avoid unnecessary downtime.
A previously used lamp was provided as a reference sample for comparison.
The replacement configuration
A low-pressure ozone-generating UV lamp was selected with the following parameters:
electrical power: 10 W;
UV output: 2.7 W;
overall length: 233 mm;
arc length: 150 mm;
rated service life: up to 4,500 hours;
operating water temperature: 5–40 °C;
ozone-generating configuration with a quartz envelope.
The main objective was not to redesign the analyzer, but to make the new lamp work with the existing installation.
Installation without modifying the equipment
The replacement lamps were installed by the plant's own technical staff using the standard mounting points.
No changes were required to:
the analyzer housing;
the electrical connection;
the lamp mounting arrangement.
This is an important point when working with analytical equipment.
Even small modifications to an existing instrument can complicate maintenance and validation, so direct compatibility is preferable whenever possible.
A staged delivery
The plant ordered 24 lamps, but only 20 were immediately available.
Instead of waiting for the full batch, the order was split into two stages:
20 lamps were shipped first;
the remaining 4 were scheduled for later production.
This allowed the plant to begin replacing the expired lamps without waiting for the complete order.
Why sample-based matching can be useful
When the original component is difficult to source, a physical sample can sometimes provide information that is missing from documentation.
For a UV lamp, useful parameters include:
lamp length;
electrode spacing;
tube diameter;
connector design;
operating current;
power;
quartz type.
These details are especially important for laboratory and process-control equipment, where there may be very little tolerance for dimensional differences.
What this case shows
Older analytical equipment can remain fully serviceable even when individual consumable components become difficult to obtain.
Before replacing an entire instrument, it can make sense to check whether the unavailable component can be reproduced or replaced with a compatible equivalent.
In this case, the analyzers remained unchanged while only the UV lamps were replaced.
The project also showed the value of testing compatibility and separating urgent quantities from components that can be delivered later.
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