>
>One purpose of the chimney is to move the air upward and then rotate the
>direction of flow to near horizontal as done by the upper curve of the
>chimney thus directing the airflow toward the anode connection. While
>we understand that air directed at one side of a cylinder does flow
>symeticrally around the cylinder. To this end it does concern me that
>the air exiting from a chimney is directed at the anode connector and
>heat sink which typically have horizontal fins. Personally not having
>measured the turbulance, I'd have to agree with others that folks at
>EIMAC made quite a study of the socket, tube chimney and anode
>connector.
? Turbulence is not the concern. Equal and opposing air flow is.
Vertical air flow needs vertical fins because vertical fins direct the
airflow upward. However, horizontal fins are easier (and cheaper) to
make. Vertical fins require a milling machine and an indexer to rotate
the work piece progressively as each fin is milled.
> Perhaps there's not as much cooling required for the anode
>cooler as we think and thus the turbulance generated is a mute point.
>
>FYI: My VHF legal limit amp uses a blower with a 6" dia wheel that is
>only 2" wide turning at 3600 RPM.
? Wow - that's a wheel speed of 5654-feet/min. -- or 1.07 miles per
minute. How much pressure does it develop across the socket?
cheers, Bob
>
>measures wrote:
>>
>> >
>> >Just an observation, the design of a chimney is such that the vertical
>> >flow of air is directed evenly around the tube envelope and as it exits,
>> >also against the anode seal & heat sink at the top. I really don't
>> >think a Coleman lantern globe or a pickle jar does the job.
>> >
>> ? Bob: Any opinion about the use of vertical air flow on horizontal
>> cooling fins.?
>>
>> >Bottom cooling is also required on many tubes due to the heat produced
>> >by the heater/filament. Socket contacts last a lot longer when they are
>> >kept cool. I've seen solder melted out of the tube pins due to
>> >inadequate cooling.
>> >
>> >As to blowers, a centrifugal blower is the only way to go. Muffin fans
>> >just won't produce the required air flow with typical back pressures
>> >presented by air system sockets. My experience says big diameter wheels
>> >that are 2" wide are better than small wheels that are 4" to 6" wide.
>>
>> ? amen . This is how Kooltronics builds their line of high-pressure
>> blowers.
>> ?
>> >Even though the two fans may spec that same CFM, this has to do with
>> >radial velocity.
>> >
>> cheers, Bob
>>
>> >Jon Ogden wrote:
>> >>
>> >> on 5/13/01 9:52 AM, measures at 2@vc.net wrote:
>> >>
>> >> > ? You don't seem to get it, Jon. A high-speed centrifugal blower is
>> >> > required to overcome the back-pressure in the SK-510 air system
socket.
>> >>
>> >> Perhaps I don't, Rich.
>> >>
>> >> And perhaps I am full of BS. But I prefer cooling systems that work in
>the
>> >> direction of natural convection of heat. Heat flows up. So something
>that
>> >> blows cool air over something in an upward direction is in my mind better
>> >> than something that blows air across it.
>> >>
>> >> Your comments about the blower and the reduction of air flow are quite
>> >> correct, I am sure. Yet, the guys at Eimac that designed the cooling
>system
>> >> and chimneys and tubes way back when weren't a bunch of boobs either. I
>am
>> >> sure they had good reason to do it that way.
>> >>
>> >> Jon
>> >>
>>
>> - Rich..., 805.386.3734, www.vcnet.com/measures.
>> end
>
>
>
>--
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>
>
- Rich..., 805.386.3734, www.vcnet.com/measures.
end
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