On Sat, 10 Jan 2004 05:40:18 GMT, Jere Lull wrote:

In article ,
(Steven Shelikoff) wrote:

On Fri, 09 Jan 2004 07:51:04 GMT, Jere Lull wrote:

In article ,
Rick wrote:

The element cannot possibly know what mechanism is used to
establish fluid flow through the filter. The only thing the
filter sees is rate of flow and as it clogs, differential.
Anyone who claims otherwise is ignoring some other factor or
talking BS.

ONLY if you're only looking at the filter.

We are only looking at the filter, not taking into account the casing,
plumbing, etc.

Steve

I believe that the case is a pretty major component to ignore in a
polishing system. A case designed for partial vacuum may not properly
handle whatever pressure the pump can deliver. If the company says "only
suction", I suspect it wasn't designed for pressure.

When looking at the entire fuel polishing system, we're not ignoring the
case. When looking strictly at the difference in the performance of the
filter media, by definition we are ignoring the case. My question is
why does it matter strictly to the performance of the filter media
whether fuel is being pushed through by a pump or pushed through by
atmospheric pressure?

Getting back to the filter alone: Since I believe most pumps can "push"
better than they can "pull", we should also consider the maximum
differential the filter can handle before it tears or otherwise breaks
down. Rich mentioned a design limit of 6" vacuum (about 3 psi?) What can
these pumps deliver?

Typical of the pumps used in this application is the Walbro 6802. I
don't see the spec on vacuum for it on the web but it delivers 7 psi
pressure so the vacuum is probably somewhat less. I do have the manual
on the boat, but I'm not going down there anytime soom. In application,
I haven't measured more than about 5 psi of vacuum before I changed
elements. The Racors have no problem with 7 psi vacuum or pressure.

Steve