[Prev][Next][Index][Thread]
Re: small tube filling pressures
Morgan wrote:
Life (hours)= (Axp^4xV)/ (kxi^2)
where A= inside surface area of each electrode
p=filling pressure of neon
V= tube volume
i= tube current
k= empeical factor based on the coating material
Note the real killer: pressure is to the fourth power
Great formula, how does the 4th power get into this equation? Any guesses?
Note also that tube area is squared (AxV), in other words, A^2xL, which is a
pretty tough factor too. There must be an additional factor dealing with the
completeness of the processing somewhere in this, I would think. The standard
tables I received from Frank Montroy who does talks on this were based,
according to Frank, on old exhaustive studies of tube life on thousands of
tubes done in the 30's by Hyde labs, I believe he said. The coating factor is
also a very important factor. I have noticed that practically the only tubes
I have ever had to repump from Neon gas depletion in any quantity were of
Tecnolux Citrus Orange, and only ones that were bent, not straight. There
were a shocking number of them, and none else.
SO, why not fill to a much higher pressure than prescribed, for all tubes,
given the formula?
Jeff Golin