Lee Oakley reveals how a UK university is benefiting from the latest in autoclave technology
By replacing a 350 litre power door autoclave with a Priorclave 450 litre front-loading autoclave, the plant research laboratory of York University’s Biology Department has benefited considerably. It has reduced energy costs and achieved a 90% reduction in water usage, all associated with the sterilising process, providing a potential saving of nearly £6,000 per year.
The Department of Biology is internationally renowned for the strength and quality of its research, teaching and state-of-the-art facilities, and is consistently ranked as one of the top biology departments in the country.
The spacious modern teaching laboratories provide an outstanding research environment from studying cancer, immunology and tissue engineering, to novel agricultural products, environmental studies and bio-archaeology.
The ‘plant’ teaching laboratory is attended by undergraduates and those studying for a PhD, researching and tackling fundamental problems across plant biology, including physiological adaptation, plant nutrition, primary and secondary metabolism, and intracellular and intercellular signalling. Within the laboratory they use a diverse approach spanning classical molecular genetics and biochemistry through to post- genomic and advanced imaging technologies.
Results have contributed to a wide range of applications from improving production of the anti-malarial drug, artemisinin to increasing the yield of bioenergy crops.
Owing to the nature of the research work undertaken, this area of the university is classified as a Containment Level 1; only those with authorisation can gain access to the laboratory. In order to maintain the highest level of decontamination risk- potential, after experimental procedures involving seed and GM investigation, all waste is carefully sterilised for safe disposal using steam autoclaves.
Space-saving design
Since installing the Priorclave RSC-450 in the head-house of the plant laboratory, side by side analysis of running costs with another autoclave has showed an overall saving of 56%, the major contribution to this massive saving is associated with cost of water supply and disposal, amounting to a reduction of 88% and 89% respectively. Since the university is in a hard-water area Priorclave fitted a water softener and again, a very big reduction of a 92% saving in salt requirements has been achieved.
The previous power-door autoclave, although only a 350 litre machine, had a much larger footprint than its replacement, the Priorclave RSC-450 laboratory autoclave. It also required a separately housed 45kW generator that ran constantly 24/7 to provide the required level of steam for sterilisation.
By replacing this with the new autoclave it has given the laboratory more free space within the actual laboratory as well as create a totally free room that previously housed the generator.
The Priorclave 450 litre autoclave is a floor-standing autoclave with a small, integral steam generator that only heats water on demand. This process cuts costs significantly compared with the previous autoclave design.
The autoclave is called into action two to three times a day, five days a week and by heating water on-demand it is estimated to save the university £7.58 per run.
Contributing to the efficiency of the Priorclave front-loading autoclave is the inclusion of a vacuum system for air removal at the start of the process with an evacuation capability down to approximately 300mb absolute.
During the steam generation process multiple vacuum stages can be programmed and are interspersed with heating stages to achieve faster and better steam penetration of the load.
After the required sterilisation cycle, assisted cooling is programmed to take over, rapidly reducing the pressure in the chamber, causing fluids present in the waste load to evaporate more quickly. By initiating a cooling action in solid items in particular, this process phase can be reduced to approximately 10 minutes.
The timed free steaming feature of the Priorclave RSC-450 autoclave with its pulsed venting for air removal contributes greatly to faster cycle times, particularly useful when sterilising problematic loads such as the heavy waste soils created by the plant laboratory.
This period allows the load to be fully penetrated with steam and expel pockets of air that may inhibit the sterilisation process.
Once a chamber temperature of 112°C is reached, the vent valve opens to reduce the chamber temperature to 107°C when the valve closes again. This cycle is repeated until the timed period is completed creating an enhanced level of turbulence in the chamber.
Setting programme cycles is done via the push-button control panel that governs the functionality of the proven, fully featured Tactrol programmable system. The autoclave supplied to York University has a five-program memory and also features a three position setting lock key- switch preventing alteration of temperature, time and option selection settings in one position, or to allow selection of programs only or full access to all settings.
Despite its relatively compact exterior, the autoclave has a large 450 litre rectangular, steam heated chamber measuring 68 x 90 x 83cm (W x D x H). It is designed for front loading, access to the chamber is gained via a three-wheel door closure system.
The wide opening facilitates easy loading of bulky and heavy items, via a trolley if required, and as used by lab staff at York University.
The 450 litre autoclave is a part of an extensive range of floor-standing, front-loading autoclaves that offer chamber capacities up to 850 litres.
The company also offers a comprehensive range of smaller autoclaves, starting at 40 litres.
Lee Oakley is with Priorclave.
