Bird Technologies 6151A - Manual (Page 14)

dielectric coolant carries the electrically generated heat from the resistor to the walls
of the cylindrical cooling tank. The tank is encased in a set of metal radiation fins
to which heat is conducted and carried off by air convection.
A synthetic rubber diaphragm located in the rear dome on the load allows the coolant
to expand as the temperature rises.
Figure 3
RF Load Section
Bird Model 6151A Termaline Wattmeter
4