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If hardware becomes galled during the tightening procedure,
remove damaged hardware by sawing or breaking and install
replacement hardware to ensure proper electrical contact
between mating surfaces. Refer to supplied installation instructions and install appropriate hangers (rigid or spring types) as line sections are being installed using proper number and type of hangers correctly spaced. Differential line expansion is compensated by bellows and spring hanger assemblies. Note: Do not support more than one section of line on flange joint without using hangers. Ensure all exposed horizontal runs are well protected from accumulated or falling ice and possible damage from other falling objects. After the installation is complete, pressurize the line and check all flange connections for leakage. Use a commercial leak detector or liquid detergent over joints and check for evidence of bubbles. Unbroken soap film over an entire joint for several minutes indicates absence of noticeable leaks. |
Transmission line must be pressurized at all times
to prevent changes in ambient air temperature from
causing condensation to occur and seriously impair
system efficiency. If moist air has entered the
system, it must be purged by removing the gas port
plug located on the gas barrier or behind the antenna
input flange. An alternative method is to pressurize
and let air escape at transmitter end of line for
one hour. Repeat procedure several times allowing
one hour each time for air to mix. After purging,
replace gas port plug and repressurize line. Pressurization can be accomplished by manual or automatic means depending upon the quantity of line in use at the station and whether or not the site is attended. A dry air hand pump is satisfactory for attended sites using relatively small quantities of line. Automatic electric dehydrators are recommended for unattended sites or where large quantities of line are utilized. A compressed air cylinder can also be used. A regulating tank in the pressurization system can be utilized to provide low pressure outputs. Note: Line assemblies are not hermetically sealed and may exhibit a low leakage rate; consequently, line installations not using an automatic air supply must be periodically inspected. Dry air or nitrogen is normally used for pressurizing. When pressurization equipment is connected to the gas port on a gas barrier, or whenever pipe fittings are reassembled, threads must be covered with Teflon tape to ensure a leak-proof connection. |
