[Amps] Coupling a blower to an air system socket

[Jim Thomson]

Date: Sat, 16 Mar 2013 19:10:17 -0800
From: "Paul Hewitt" <wd7s at earthlink.net>
To: "Ian White" <gm3sek at ifwtech.co.uk>, "'Jim Garland'"
<4cx250b at miamioh.edu>, <amps at contesting.com>
Subject: Re: [Amps] Coupling a blower to an air system socket

Greetings Ian
Besides the lower back pressure advantage of blowing into the anode
compartment, this method also cools the tank components. This helps reduce
thermal tuning drift in very hi-Q tanks.
73, Paul

PAUL HEWITT
WD7S PRODUCTIONS
QRO HOMEBREW COMPONENTS

## Brilliant, never thought about cooling tank components that way. 
For tubes like 3CX-3000A7 or 3CX-6000A7, they both use a 
coaxial filament stem.   If your cooling scheme is used,  with air
pumped into the above chassis area, and chimney from  anode to
top lid, like the k2riw arrl method,  it will work,  but with these coaxial
fil tubes like the 3x3 and 3x6,  Eimac sez to shoot 5 cfm  BETWEEN
the coaxial fil stem assy.   A simple method of doing this is to use a 
small diam, flexible  plastic tube, and a fitting to chassis... and use some of the
compressed air from top half of amp compartment, above the chassis, and direct
it down the flex tube... then direct the tube between the fil stems. 

##  On the YC-156  80-10m amp my buddy just finished, the  CX-33
blower is located in the basement below him, so even with a long piece
of metal type  dryer hose used,  no big deal.  The  CX-33 puts out one
helluva lot of pressure.   Another similar dyer hose is used to get the hot air
from back of amp down into the basement....so it’s a loop,   

## end result is NO heat and NO noise in the shack.  Blower and HV supply are
one floor below, and remote switched.   5-10 min blower over run included.
Those CX-33 blowers are real easy to slow down with a small variac or 
resistor.   An airflow switch was also included.   Cold  or cooler air from the
basement is ideal for cooling a tube.  In winter, hot return air is pumped into
basement.  In summer, its  ducted to the outside. 

I like the idea of paralleling the two air restrictions... instead of the more normal 
series method.   and you could still remote the blower too. 

later.... Jim  VE7RF