Challenging claims of lower Autoclave running costs to square the circle

Challenging claims of lower Autoclave running costs to square the circle

Choosing between a square or round chamber autoclave should be decided by correct specification, load flexibility and control systems technology.

There are two main types of autoclaves to consider under biological sterilization situations. There are the feature-rich large capacity units often used in high through-put facilities (such as CSSD or pharmaceutical production); these typically have square section jacketed chambers in order to maximise load area, and aid heating and cooling. Alternatively there are the smaller, lower cost, lower (claimed) energy usage sterilizers used in most laboratories for media preparation, empty glassware and general laboratory equipment. These units are normally of circular section chamber design where the capacity per cycle is less of an issue and they are used only as and when needed.

Circular chamber autoclaves are generally of non-jacketed construction, requiring less energy to heat the chamber to temperature and pressure, and usually having little or no cooling other than natural heat loss – but this comes at the cost of long cycle times. Considering the latest standards on drain water temperatures and water regulations, be wary of some claims that water and power usage is as low as suggested. Cooling drains to below 60°C needs cold water or some other method to reduce the waste water temperatures from the autoclave.

Remember: It’s easy to claim low energy and water consumption, but it takes the same amount of energy to heat a specific load (i.e. bottled fluids) from one temperature to another no matter whose autoclave it is.

The biggest issue with these basic types of sterilizers, often fitted with low technology control systems, is they are limited in what they can sterilize, and even more the limitation of the control system can make them out of date very quickly.

Some claims of lower running costs can be substantiated, but we have first-hand experience of many customers that were drawn in by the appeal to soon realize the process limitations and that they really needed a sterilizer which is multifunctional. A modern sterilizer capable of different sterilisation functions/load types can be cost effective too if it is specified correctly.

Most laboratories want to have the ability to sterilize much more than just media and empty glassware, and the efficiency of the lab is also important, so the sizing of chamber to specific load types and achieving certain cycle times is high on the agenda when the unit is being specified. Also many lab users expect to process difficult to sterilize items such as pipette tips or wrapped instruments, which need good air removal and to be dry at the end of the cycle. These items cannot be processed and be dry at the end of the cycle in a simple research grade or laboratory sterilizer.

Modern multifunction autoclaves with square or round chambers, jacketed or non-jacketed, with the latest controller technology can be more expensive to buy in the first instance but you get better flexibility and they can eliminate the need for several sterilizers to do the job(s), so it can be a false economy to by the cheapest unit available.

Astell autoclaves can be programmed to work like basic lab sterilizers and only produce steam and use water when it's needed, making them very economical, but with simple programming can also be set up to have steam on demand for quick cycles and dry loads.
Autoclaves with integrated steam generators are ideal for dense porous loads and heavy destruct discard loads.

Even with all the features turned on an Astell design makes best use of power consumption, and water usage. Energy is only used when needed and if the unit is left unused or left on overnight it can turn itself off to idle just to keep warm. Cooling water is recirculated and temperature controlled to reduce the amount of water going to waste unnecessarily.

  • Latest touchscreen technology
  • Total flexibility for programming (password protected)
  • Integral Steam Generators that only produce steam when needed
  • Jacketed / non- jacketed pressure vessels for heating and cooling
  • Electropolished chambers
  • Vacuum system with water recirculation to reduce water usage
  • Internal fans for super quick fluid cycles
  • Single doors / double doors
  • Manual doors / automatic doors
  • All the safety features to the latest standards
  • FDA 21 CFR Part 11 compliant software

For more information on our range of circular and square chamber sterilizers, or to talk through your requirements with an expert and get free help and advice, please Contact us.

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