Solving complex dry air supply and control problems

Drallim is a long-established supplier of waveguide dehydrator equipment helping to provide a clear signal for radar and microwave applications to the aerospace, telecommunication, and broadcast industries worldwide.

Dry air compressed into a copper cable will he copper from the potential ingress of moisture, improving reliability and clarity, and reducing long-term costs. This is especially important where widespread adoption of broadband services requires optimum cable performance. This pressure can provide an additional facility of allowing maintenance engineers to predict and locate potential faults by identifying holes in the cable sheathing.

The dehydrator is a crucial element of any communications system, be it a microwave, radar, TV satellite & terrestrial or antenna system. Its purpose is to provide dry pressurised air to the aerial transmission tower, the waveguide itself and its associated components.

The air pressure supplied by the waveguide dehydrator is elevated above atmospheric, thus protecting against the ingress of moisture from changing weather conditions, and dried to the extent that this air does not condensate, therefore maintaining signal quality.

The pressure available at the outlet, which can number one to twenty (generally 3 – 10), can be set by a panel mounted regulator, which can be tamperproof if required. Alarms, set at appropriate levels relative to the required output pressure are displayed on the front panel but can also be monitored remotely. The alarm equipment monitors all aspects of potential aerial pressure failure, which include high humidity, low pressure, and mains failure.

Front panel controls are kept to a minimum; those included are to give operator confidence without necessary intervention.

A small pressure vessel is incorporated within the waveguide dehydrator to ensure a stop-start cycle, rather than the integrated compressor running continually. A differential pressure switch controls compressor operation. This vessel stores dry air at increased pressure, being drawn off to the waveguide at the lower pressure set by the regulator. This also has the added benefit of providing extra capacity in the event of a sudden increase in dry air requirement, giving a bit of added time to carry out repairs.

A small bleed of air can be deliberately introduced to ensure a regular change of air within the waveguide system as felt necessary.

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