As the humid compressed air passes through the Hi-DRI unit, water vapour diffuses through the walls of the hollow membrane fibres without loss of compressed air. At the dryer outlet, a small volume of the now dry air is expanded and released into the annular space between the membrane fibres and the outer aluminium shell. This air purge then sweeps away entrained water vapour to atmosphere as a humid air stream.
Hi-DRI air dryer makes it easier and less expensive to supply pneumatic equipment and instrumentation with clean, dry compressed air. This simple, proven technology helps eliminate condensation, oxidation and microbial growth, resulting in reliable and predictable performance of downstream air operated equipment. It also reduces component failures, improves equipment performance and operator satisfaction while showing savings on both warranty and production costs.
These dryers are designed to provide the superior solution for existing compressed air systems, maintaining maximum process reliability while remaining virtually invisible to the process installation. They do not contain moving parts and there are no desiccants or refrigerant to replace. They are also compact and lightweight, do not incorporate valves, drains or electrical connectors and do not require adjustments.
Filtration combined with compressed air drying contributes most to the performance and reliability of airline powered operations. Humidity in airline systems is a major factor of corrosion and tooling wear, which can lead to production breakdowns. However, humidity also creates conditions conducive to the growth of micro-organisms within an airline, which can result in contaminated condensate. This is obviously highly detrimental in food or pharmaceutical production processes as well as in dental, medical or laboratory applications. Almost any dewpoint can be achieved, even when accommodating high humidity ambient conditions as experienced outdoors, in open workshops or on seagoing vessels.
These Hi-DRI membrane air dryers are suitable for a wide range of industrial plant installations including specialised commercial operations. The range of models available cover air flow rates from 17 to 1050 litres/min. Multiple dryer units can be used in parallel to achieve higher flows where required. Outlet dewpoints from +15° to -40°C can be achieved at 7 barg pressure (12.5 barg max) and with 35°C inlet air temperatures.
With in-line connection ports at each end, the dryers can be easily integrated into an existing airline. They are compact, lightweight and cost effective, while the polymeric hollow fibre membrane is maintenance-free and does not need replacing where adequate pre-filtration has been provided. A 0.01 micron coalescing filter element is recommended to prevent damaging particulates, oil aerosols and liquid water entering the Hi-DRI filter. The use of a Hi-line HF series filter with regular replacement of the cleaning element will ensure long-term continuous, trouble-free dryer operation.
Where cost effective centralised refrigeration drying is required, a Hi-line CDA dryer connected directly to a compressor can be combined with individual Hi-DRI units of varying outputs fitted at points of use.