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Waveguide Antenna & Telecommunication Cable Dehydrator – Selection Tool

Drallim has been designing and manufacturing Waveguide Antenna and Telecommunications Cable Dehydrators for over sixty years, offering a range of units that provide a continuous performance of dry, low-pressure air. These dehydrators are utilised with broadcasting antenna feeds, dielectric coaxial cables, telephone, and waveguide systems.

Employing tried and tested methods to ensure energy-saving integration and low noise levels, Drallim’s systems can be situated in manned sites, boasting good MTBR (Mean Time Between Repairs). Whether it’s a customer-specific requirement or a Drallim standard design, the company consistently utilises top-quality materials for their dehydrators, resulting in high efficiency, low pressure drop, and a small footprint. This approach not only reduces power consumption but also minimises installation time and facilitates maintenance.

Drallim Dehydrators come complete with humidity detection equipment and a valve to release wet air to the atmosphere in an alarm condition. Alarms can be monitored visually using the unit’s panel-mounted indicators or remotely via the external alarm terminal. The alarm equipment monitors all aspects of potential aerial pressure failure, including high humidity, low pressure, and mains failure.

Drallim offers a range of monitoring accessories to complement their specialised dehydrator range, enabling users to remotely monitor the antenna feeder or cable network pneumatic system along with the condition of the dry air and the dehydrator itself.

See the chart below to choose the best unit to suit your requirements


Drying Principles of Drallim Dehydrators

The drying process is achieved by means of a two-tower, non-heated, regenerative desiccant molecular sieve adsorption system. One tower is kept under pressure to aid in the adsorption of moisture, while the second tower is purged by expanding a small percentage of the dry air feed to near atmospheric pressure, and passing it over the desiccant in the second tower. The moisture-holding capability of the dry purge air is very high, enabling moisture to transfer from the desiccant (with a higher vapor pressure) to that of the purge air, which is then exhausted to the atmosphere via solenoid activation. Each bed is controlled by a process timer for sequential reactivation and regeneration, enabling continuous airflow to be maintained. Most Drallim dehydrators house an integral air receiver, which allows the compressor to remain inactive for extended periods of time, reducing running costs.

Waveguide Antenna and Telecommunications Cable Dehydrator Selection Chart

Dry air DeliveryOutput Pressure

Output Pressure

Number of OutletsCompressor TypeOutput FlowmeterAir Receiver (Litres)Sound DampeningNoise Level
External Alarm
Monitoring (Volt free contact)
VoltageCurrent RatingUnit Mounting Method
1243430ft^3/hr0.5-7psi0.5-15psi31/3 HP2No**82032020030Yes230vAC 50Hz1.7AWall/Floor
124367ft^3/hr0.5-15psi31/10 HPYes0.7No**13348237829Yes230vAC 50Hz1.2ARack
*1243730ft^3/hr0.5-7psi0.5-15psi5 or 101/3 HPYes10Yes**96044033049Yes230vAC 50Hz2.1AFloor
12445/S5ft^3/hr0.5-7psi31/16 HPYes0.7No**38050015917Yes230vAC 50Hz1.3AWall
12445/M13ft^3/hr0.5-7psi31/8 HPYes0.7No**43053022524Yes230vAC 50Hz??Wall
12445/L30ft^3/hr0.5-7psi3 or 61/3 HPYes0.7No**43053022525Yes230vAC 50Hz1.9AWall
*1245730ft^3/hr0.5-7psi0.5-15psi5 or 101/3 HPWith (Optical Alarm)10Yes**106044333056Yes230vAC 50Hz2.1AFloor
1237730ft^3/hr0.5-15psi11/3 HP0.7No**6033032529Yes230vAC 50Hz1.7APortable
12269180ft^3/hr0.5-15psi5 to 803/4 HP TwinYes30Yes**1848 / 2240560780200Yes230vAC 50Hz1.3AFloor


Other variants are available:

*Dual Unit Master/slave Options. Combination of Dual 12437 type, dual 12457 types.

All units work down to -40°C (0.5%RH at 21°C)
Wet switch point -20°Cdp Reset at -25°Cdp
**Typically 60dBA maximum at 1 Meter, all planes.
Environmental operating conditions/Considerations (0°C-40°C)

Product Enquiry

Please contact our sales for the product information. E-mail : [email protected]