Селикагелевый патрон

Now transmission line system designers and operators have a superior alternative to bottled nitrogen gas and desiccant dehydrators, especially at remote sites. The Andrew SD-003 Static Desiccator eliminates the maintenance associated with tanks and other active systems. • Simplicity in design • Requires no electrical power • Fully automatic • Excellent for remote sites • UV stable housing • Easy mounting and access Our newest addition to the family of static desiccators provides the industry for the first time with a passive drying device that covers systems with volumes from 0.01 to 1 ft3 (0.01 to 28 liters). Short length flex-twist sections, rigid sections, and elliptical waveguide sections can now be kept free of moisture with a device that functions without the aid of electrical power and mechanical pumps. The SD-003 offers operational reliability, a technologically superior drying mechanism, and easy installation—all backed by a company that is a leader in the industry. The SD-003 operates on a simple principle of nature—the path of least resistance. The device itself is comprised of a molded clear plastic housing containing color-indicating silica gel desiccant. The top of the housing is formed to resemble a piece of 3/8-inch poly tube and mates with a male 1/8-inch NPT fitting installed into the gas-inlet port on a waveguide flange or pressure window. Adapters are available for attachment to metric thread systems. The bottom of the main housing is pierced with a very small “breather” hole.

As the waveguide warms during the daytime portion of a cycle, the air inside expands and a portion enters the SD-003. Pressure is equalized through the “breather” hole, which offers the path of least resistance and eliminates movement of moisture across the flange seals of the transmission line.

In the night portion of the cycle, as the air inside the waveguide cools and contracts, make-up air is drawn through the SD-003. During both portions of the daily cycle, the air passes over the desiccant material and moisture is adsorbed into it.

The clear wall of the unit allows visual inspection of the desiccant condition. As moisture is adsorbed the color will change from deep blue to pink/white. When 80% of the desiccant material has changed color, the unit should be replaced.

The useful life of a static desiccator depends upon system volume and a number of climatic factors. For a typical case experiencing an average temperature change of 40º F (22º C) per day at 40% relative humidity, the SD-003 can be expected to last for more than one year.

Typical application of the SD-003 is for short lengths (up to 3 meters) of flexible waveguide. The table below shows lengths of waveguide at various frequencies that have an equivalent internal volume of 28 liters. When protecting lengths greater than 3 meters, the waveguide run must be purged with dry air before installation of the SD-003.