Thursday, 3 March 2011

Bespoke agar-drying cabinet for university

PF&F, the specialist British manufacturer of laboratory fume containment systems, has recently completed the production of a bespoke agar-drying cabinet for the division of Biomedical Science at the University of Bradford, UK. The recently installed system has been acclaimed by the University’s microbiology staff as an unqualified success.

The new ADC unit is the latest addition to the PF&F product range and is designed to enable agar plates to be dried cleanly and effectively in readiness for inoculation with bacteria and other agents.

The preparation of an agar plate involves first pouring the agar and then allowing it to set. An essential part of the preparation process is then to dry the surface moisture because introducing bacteria or other materials directly onto a liquid surface would lead to their rapid and uncontrolled dispersal across the plate, rendering the production of single colonies impossible. Most agar plates can be left to dry on an ordinary work bench but certain specialist agars, including those that are mixed with temperature-sensitive materials such as blood, egg yolk and antibiotics, require refrigeration and therefore need additional help to dry. It was for this purpose that the University required the new cabinet.

Following a recommendation from a laboratory equipment specialist, the University’s Senior Microbiology Technician, Thelma Howley contacted PF&F with a view to commissioning the company to produce a bespoke solution. Her department had already used two cabinets from other manufacturers, but neither of them had been purpose made and neither had worked satisfactorily.

Following detailed discussions, PF&F’s design team proposed a product that would maintain a steady, temperature-controlled airflow and recommended that the incoming air be pre-filtered in order to prevent accidental contamination of the agar by airborne bacteria or other materials.

Another requirement was that the system should be capable of drying a large number of plates simultaneously so as to keep pace with the Biomedical Science division’s busy timetable. Thelma Howley herself explains: “We are often required to produce a huge number of plates and, through term time, the turnover of plates can be enormous so time is at a premium. Having an effective drying unit is therefore a vital aid to rapid turnover and the efficient running of practical classes for the students.”

Having agreed the specification, PF&F then began manufacturing the agar-drying cabinet on the understanding that the client would only have to pay if it was completely satisfied with the unit’s performance. The cabinet was completed according to schedule and Thelma Howley then visited PF&F’s factory to test it for herself. The trial was completely successful and the unit was installed at the University shortly thereafter.

The finished ADC unit creates ideal drying conditions by first taking air into its lower chamber through a pre-filter and introducing thermostatically controlled heat. The warmed air then passes through a HEPA filter into the drying area itself, which is fitted with multiple drying racks. Finally, the air is exhausted via a third filter, thereby creating a steady laminar flow.

University staff have been impressed by the performance of the agar drying cabinet.

“The design of the unit is very smart, modern and ergonomic to use,” notes Thelma Howley. “Our technicians have tested the unit thoroughly and it has been found to be extremely efficient. It performs in an excellent manner, meeting all the criteria for which it was designed. It has been found that most agars will be dried and ready for use in approximately ten to fifteen minutes. The airflow is even throughout the cabinet and dries plates equally well regardless of their position within it. All in all, it’s a wonderfully designed, easy to use unit that works efficiently and effectively.”

Featuring a low-noise centrifugal fan and a low airflow indicator, the ADC is a standalone cabinet that can be supplied as a bench-top or free-standing unit. Made of epoxy coated steel with clear acrylic windows, it is available with either single or twin doors, which are lockable for added security. Its typical dimensions are 1200x500x800mm (WxDxH) but special sizes can be manufactured to order. It is simple to operate and requires only a standard, single phase 230v 50Hz electrical supply.

The ADC is the latest addition to PF&F’s broad range of fume containment and extraction systems. These include fume cupboards, ventilated enclosures, drying cabinets and many other specialist products. The company is accredited under ISO9001, the international standard for quality assurance and it offers a complete design, manufacture, installation and commissioning package.