"ABSOLUTELY" correct Mark ;-) Richard Bockwinkel Cellular: 913.579.7688
Specializing in Steam Systems Optimization ERB & Associates, Inc. www.erbsteam.com 1.866.610.3477 RapidFAX On Feb 27, 2011, at 6:45 PM, Mark E Ludlow wrote: > Hi Toby, > There is no difference, really, between pressure and vacuum. If we just start > to think of anything that has no pressure at all as Zero Pressure; normal > Atmospheric Pressure as 14.69 PSIA (PSI absolute) and so forth, then we > won’t get into trouble. Pump sizing always considers the Absolute Pressure > (e.g. PSIA) at the inlet and outlet, not the Gauge pressure (e.g. PSIG). A > third concept is Differential Pressure (e.g. PSID). A pump increases the > pressure (measured across the Inlet and Discharge Ports) as a differential > pressure gain, more-or-less irrespective of the Absolute Pressure environment > that it operates in. > There is really no such thing as “Vacuum” conveying. This only refers to the > fact the transport network operates at or below the ambient pressure and is > operated this way to help reduce fugitive losses of transported materials. A > vacuum cannot move anything; it is the force of pressurized gas behind the > transported material that provides the propulsive energy. In the case of a > conveying system connected to a positive-displacement “vacuum” blower, the > force is a maximum of 14.69 PSI, enough to “lift” a water column 33.9 feet, > hardly any stretch at all for a pump, though the work done will be the same > regardless of the method used. > When someone says: “Gravity doesn’t exist; the world sucks!”, this is a very > special case of the above that awaits the practical manipulation of > anti-gravity. > Best, Mark > > From: [email protected] > [mailto:[email protected]] On Behalf Of Toby > Seiler > Sent: Sunday, February 27, 2011 3:42 PM > To: [email protected] > Subject: [Gasification] Benefits of boosting compression ratio with producer > gas > > Sorry Tom, I didn't ask the question correctly (or I may be off in left > field). This comes from some time spent in a place called Flow Dynamics > Laboratory where inlet design of blowers was being tested. My application > was sawdust material moving. Dan, the owner, explained how pressure was much > more effective than vacuum for moving mass. He explained that drag in a > vacuum is hard to overcome, while pressure fills the space with molecules and > can push materials great distances. > > When talking engines, for example on my 74 Ford f600, I watch the vacuum gage > and see that it is around 18-22" of vacuum, warmed up 1200 rpm or so (driving > hydraulic pump). So what goes to the cylinders is not atmospheric pressure, > it is around half, perhaps less. > > I'm trying to understand how engine efficiency is related to both air and gas > pressure and density. If producer gas is operating with 18/1 in a normally > aspirated engine, due to high octane, how will the ratio be affected if one > has positive pressure at one or two pounds? > > Seemingly this would involve air flow across an orifice, similar to a > butterfly valve (throttle), but I am at a loss for a good start point. > > Given a large quantity of air and gas to make comparable power (not large > derated), the flow of air/gas in a large displacement engine would seem to be > a much more critical factor than just saying the cylinder is seeing > atmosphere pressure and forgetting the drag that manifolds, throttle valves > and pulling gas from a gasifier creates (in a suction system). I can hardly > see a direct linear relationship. > > My work is a low pressure system, so this is not an academic or theoretical > discussion that I will never act on and I'm at a point of determining engine > for a CHP and what internal modifications to plan, if any. I have several > engines, a 345 International, a 460 Ford, a Cumins 5.7 (with needed repair), > a 7.3 International (in a ford truck also needing repair). > > Sorry if this is confusing or not cogent. I'm trying. > > Toby > seilertechco > > > > > > _______________________________________________ > Gasification mailing list > > to Send a Message to the list, use the email address > [email protected] > > to UNSUBSCRIBE or Change your List Settings use the web page > http://lists.bioenergylists.org/mailman/listinfo/gasification_lists.bioenergylists.org > > for more Gasifiers, News and Information see our web site: > http://gasifiers.bioenergylists.org/
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