New autoclave uses compact process valves to meet cost and performance targets

29 April, 2015

ESTS has been manufacturing commercial autoclaves for over 10 years and has a large choice of models available. Most are employed to sterilise items such as porous loads, fabrics, utensils, glassware, fluids and plastics for both laboratory and medical use. The latest model however is billed as a ‘game changer’ by the designers due to its ability to deliver a substantial reduction in overall energy usage and operating costs.

The latest and largest of the compact vertical closing, rectangular chamber machines; the Logiclave LAB300 has just been launched with the company’s revolutionary flash steam generator on board. The unit comprises fourteen Bürkert valves, some of which have been adapted to reduce inventory and purchase costs as well as withstand the high temperatures associated with repeated steam sterilisation.

The LAB300 uses pulsed vacuum/pressure cycles to replace the air in the chamber with steam in order to achieve sterilising conditions. When the cycle starts the first of the Bürkert valves, a stainless steel bodied Type 2000 pneumatically operated angle seat valve, opens as an exhaust and then closes when the machine reaches a vacuum set point of 100 millibar within the chamber. When it reaches this level, steam is injected via another Bürkert angle seat steam valve.

The specification of the valves in this instance is very important in order to achieve high reliability over an extended operating life with frequent and arduous operating cycles. The steam supply valve is a high temperature unit that has been specified by process valve supplier Control Stream to include PPS material to ensure a longer seal life in the actuator.

Compact but reliable

The valve body selection was also important to provide a compact solution; the bodies of Bürkert’s latest generation of angle seat valves are considerably smaller than other older designs and helped to ensure a compact, but reliable final product.

A number of the angle seat valves were also supplied with a male thread which is a specification developed for Control Steam as a first for this application. This reduced inventory purchase costs for the machine builder by reducing the number of joints and connectors required to construct the piping circuit. Essentially a benefit just to the OEM, it does however add to the overall cost competitiveness of the machine.

The flash steam generator in the LAB300 is used to create steam on-demand. This is far more efficient than a more conventional pressure vessel boiler arrangement that heats a volume of water to produce steam and then maintains it throughout the day, constantly using energy to battle insulation losses.