[Gasification] star valve sources/experience?

[Art Krenzel]

My industrial experience included a bout with feeding a wet granular/powder 
between a pneumatic conveying system and a dryer.  We lost an incredible 
amount of operating time trying to  keep a star valve working in that 
environment because the seals would glaze over and we would lose the 
pressure seal.

I had them convert to a DUSTEX double chambered valve and the problems 
ceased.  The DUSTEX valve has two chambers separated by a pneumatically 
actuated mechanical "flapper valves".  Being pneumatic, they were able to 
operate with sufficient speed to prevent material from lodging in the seal 
area.  These valves are also made in mechanically cam driven versions as 
well.

We had the inside of the valve "painted" with a heat cured Teflon to prevent 
material adhesion and installed it.  From that day on, the problem of 
feeding solids between two different pressures ceased.   Fortunately, we had 
sufficient other problems to keep me busy but that problem ended then and 
there.

I would offer you that experience.

Art Krenzel


----- Original Message ----- 
From: "jim mason" <jimmason at whatiamupto.com>
To: "Discussion of biomass pyrolysis and gasification" 
<gasification at listserv.repp.org>
Sent: Sunday, September 16, 2007 3:48 AM
Subject: [Gasification] star valve sources/experience?


> what is the collected wisdom here on sources for star valves?
>
> granular fuel handling and ash/char handling often requires star
> valves to maintain air seal while moving solid material.  i have not
> been able to find common installations of these elsewhere for
> repurposing in gasification.  the ones i do find from general
> industrial supply sources are terribly expensive.
>
> there must be lots of these used in ag and food processing that are
> more resonable.
>
> anyone have leads or experience to offer?
>
> jim
>
>
> --------------------------------------------------------------------------------
> jim mason
> website: www.whatiamupto.com
> current project: mechabolic (http://www.mechabolic.org)
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