[Gasification] [Fwd: [Stoves] FLOWMETER]

[Thomas Reed]

Dear Art and all:

Thanks again for the heads up, and WHERE do I buy the Chinese sensors?  
I purchased several US made ones for ~$400 a year ago and hesitated to 
use them.  For now, I think the answer is that you must use them for 
clean air, not tarry hot gas which will confuse them.  The Air/Fuel 
ratio for a great deal of gasifiers is ~ 1.5, and so you can /estimate/ 
the gas flow from

1.5 air + 1 fuel = 2.5 gas

Wish we could visit over a beer....   It's been a long while.

TOM REED          BEF

------------------------------------------------------------------------




Art Krenzel wrote:
> 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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-- 
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