[Amps] Arc distance

[Ian White GM3SEK]

Will Matney wrote:
>>>Getters like zirconium
>>liberate
>>>hydrogen gas when heated above 300 deg C, and start working around 700-800
>>>deg C to absorb O2, CO2, CO, etc. The optimum temperature is said to be
>>1400
>>>deg C. Tantalum though does not have the problem of emitting hydrogen gas
>>>and its optimum temperature is around 1000 deg C if I recall.
>>>
>>Overnight I remembered some older correspondence about this. Because
>>getter materials mop up different gases at different
>>temperatures, some transmitting tubes have multiple getters at different
>>locations, possibly using different materials as well. For example, the
>>3-500Z has getters located at the base of the grid and the base of the
>>filament, as well as the big one sprayed on the anode (information from
>>an Eimac tube designer).
>
>
>Ian, correct, that's the only way it could have ever worked. Zirconium 
>on the anode only would have left a tube full of hydrogen gas. 
>Something else had to be heated up to collect it. In some ways, 
>hydrogen is worse that the other gasses because of the speed in the 
>ions it creates.
>

What is your reference for the behavior of various getter materials as a 
function of temperature, Will?

"Full of hydrogen gas" would be an exaggeration, but I see the point 
you're making.



-- 
73 from Ian GM3SEK
http://www.ifwtech.co.uk/g3sek