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When investing in a laboratory autoclave, it is expected that the product should be reliable and long-lasting.However, to perform successfully, it needs to be cared for correctly, as Ranjit Rai, Service Manager at Priorclave Ltd, explains.

Priorclave knows for a fact that there are several of its laboratory autoclaves still successfully operating after more than 23 years. The longevity of these machines is due to regular servicing by its fully trained service engineers.

Many see an autoclave as capital expenditure and, to keep ownership costs and laboratory expenditure down, they may neglect to invest in service contracts. However, with proven extended life expectancy arising from regular servicing, inspection and validation checks, laboratory life continues without interruptions and, financially, there is a much reduced lifetime ownership cost, extending the payback on the original capital outlay over many more years.

THE AUTOCLAVE The uses of an autoclave in cleanrooms, educational establishments, pharmaceutical research and test laboratories, as well as manufactures are varied

but principally either destroying any micro-organisms in a load – whether it be Petri dishes and glassware used in lab processes such as culture growth, discarded waste or clothing, testing for component fatigue or curing plastics. The overall objective is achieved through sterilisation which is designed to render items safe, ready for subsequent disposal or re-use.

Improperly autoclaved materials can result in contamination, lost time and wasted money and much worse in extreme circumstances.

THE KEY FACTOR Is there the correct correlation between pressure and temperature within the sterilising chamber? Get this wrong and proper sterilisation fails.

The intensity of saturated steam within a sealed pressurised chamber creates the perfect ‘killing’ environment to eradicate contaminants. And it is this basic principle behind every laboratory autoclave and research grade

steriliser. To ensure that sterilisation takes place within the chamber, it must contain dry saturated steam held at temperatures typically up to 138°C and at pressures of up to 2.4bar.

On-site, it is the responsibility of the service engineer to ensure these processing parameters are achieved by carrying out a series of visual and more dynamic testing.

One of the more simple tasks is inspection of the chamber door seal both visually and by feel [Fig 1]. It enables the engineer to identify any damage that could ultimately lead to escape of steam, potentially dangerous for lab staff as well as preventing sat isfactory completion of the sterilisation process.

In actual fact a thorough service check should cover all aspects of the autoclave’s mechanical and electrical systems in accordance with a pre- defined maintenance checklist, our service list details up to 72 specific points to be checked.

GETTING HOT As mentioned earlier, accurate temperature control is essential. To ensure an autoclave reaches its correct thermal setting, calibrated thermocouples are connected next to the temperature control probe and monitoring probes of the customer’s autoclave. These are coupled to traceably calibrated digital thermometers and recorded readings we checked against those shown on the temperature controller and ancillary equipment. [Fig 2]

Competent autoclave service companies operate a UKAS calibration

FIG 1 20 | Tomorrow’s Laboratories

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