[Gasification] [Fwd: [Stoves] FLOWMETER]

[Art Krenzel]

Tom,

I am currently doing a project using a mass air flow sensor to measure air 
flow to a new heater design we are building.

You did not tell the readers the GOOD news.  I am purchasing these Mass Air 
Flow Sensors for $13 each from China.

The bad news (for gasification applications) is the platinium heater is 
easily contaminated with tar and gives erroneous readings when that happens. 
The unit has a "burn off" cycle to clear itself however there is no 
indication that the readings are in error up until you clean the heater 
again.  It does not tell you when the sensor needs cleaning.  My application 
is clean air so I do not suffer from this problem.

The Mass Air Flow Sensor is automatically compensated for variations in 
inlet temperature and air density and best of all - it has no moving parts!

Art Krenzel


----- Original Message ----- 
From: "Thomas Reed" <tombreed at comcast.net>
To: "Agua Das" <aguadas at onebox.com>; "Shivayam Ellis" 
<shivayam.ellis at comcast.net>; "Jim Fournier" <jim at planetwork.net>; "David G. 
LeVine" <dlevine at speakeasy.net>; "GASIFICATION" 
<GASIFICATION at listserv.repp.org>
Sent: Wednesday, July 04, 2007 5:35 AM
Subject: [Gasification] [Fwd: [Stoves] FLOWMETER]


Dear David G. LeVineGasifiers All:

David, thanks for the tip. The problem of measuring air and gas flow
reliably and cheaply has dogged gasification from early days.

It is my observation that the GASIFICATION discussion group is a lot
more technically inclined than the STOVE  group.   This is appropriate.
A fully automataed gasifier, designed to operate a modern combustion
engine to generate power needs to have oxygen sensing, fuel feed
measurement etc. under automatic control while many STOVERS are
satisfied with a moderately clean flame.  (However, I have heard that
more advanced European pellet stoves incorporate an oxygen sensor).

A year or so ago, realizing that every car on the road measures air flow
accurately and cheaply, I bought a mass flow sensor (1990 Chev?) that
had all the right mechanical parts, but back-engineering the electronics
was beyond me and others I consulted.  So Dave's tip is halfway to
solving our problems.  Now we need a simple circuit from one of you
wizards that will identify the pin-out on the
Cardone Mass Air Flow Sensor: Remanufactured
<http://www.partsamerica.com/BrandCategories.aspx?MfrCode=A1C>
*Part Number: *749549


and how to convert this to

    * A 0-5 V signal for control
    * A display for monitoring

I look forward to the second half....

Measuring the flow of product gas is also important for automatic
gasification and I hope that this same meter could be used after the gas
is cooled to room temperature (just before entering the engine or
flare).  The molecular weight of air (~28.8 g/mole) is part of the
necessary equation, but fortunately the MW of producer gas is close to
that of air, since it is typically composed of 50% N2 and 20% CO, both
with a MW of 28 while the typical 18% H2 (MW2) is balanced by the
typical 5%  CO2 (MW 44).  Close enough for control work.

Onward to simpler solutions,

TOM REED                     BEF/BEC
-------- Original Message --------
Subject: [Stoves] FLOWMETER
Date: Tue, 12 Jun 2007 23:05:30 -0400
From: David G. LeVine <dlevine at speakeasy.net>
Reply-To: Discussion of biomass cooking stoves <stoves at listserv.repp.org>
To: Discussion of biomass cooking stoves <stoves at listserv.repp.org>
References: <12063.152.50.3.3.1181698546.squirrel at www.velocity.net>



There is a good electronic flow meter which is available worldwide at
moderate cost.  The one I have will measure in excess of 12,000 LPM
and is sensitive enough to measure a few LPM, holds calibration and
can be used in less than benign environments.  The sensor is
available from
http://www.partsamerica.com/ProductDetail.aspx?MfrCode=A1C&MfrPartNumber=749549&PartType=473&PTSet=A
for under $100 (US).  They are available from scrap yards for much
less, I would assume.

What is it?  It is a Ford "mass flow sensor" used in most later model
Ford engines, GM probably uses a similar one.  Basically it is a hot
wire anemometer which measures the air coming into the engine for
fuel computations.

Sometimes there is technology which will make your job easier
available off the shelf <GRIN>.

David G. LeVine
Nashua, NH  03060


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-- 
ÐÏࡱá

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