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rv8ch

Joined: 10 Jan 2006
Posts: 250
Location: Switzerland

Posted: Thu Feb 16, 2006 10:29 am Post subject: fluid level sensor needed

Hi,



I'm looking for a fluid level sensor that I

will use in my Subaru engine cooling system.



I've found lots of on/off switches that will

tell me if there is coolant there or not, but

does anyone know of a reasonably priced sensor

that will give me analog output over a range

of values?  Reasonably priced means to me

something less than about $250.



Thanks!

Mickey

-- 

Mickey Coggins

http://www.rv8.ch/

#82007 finishing

_________________
Mickey Coggins
http://www.rv8.ch/

mark.steitle(at)austin.ut
Guest

Posted: Thu Feb 16, 2006 10:56 am Post subject: fluid level sensor needed

Mickey,

How much space do you have to work with?  Maybe you could use a

float-type fuel level sensor and shorten the arm so that it fits inside

the reservoir.



Mark S.  



--

frank.hinde(at)hp.com
Guest

Posted: Thu Feb 16, 2006 11:19 am Post subject: fluid level sensor needed

I don't know about a level sensor but in my ea81 I use a pressure

guage...If pressure goes away after take off it means I have a leak and

have to land anyway...Its worked pretty well for 400 hours.



Just an idea



Frank 



--

rv8ch

Joined: 10 Jan 2006
Posts: 250
Location: Switzerland

Posted: Thu Feb 16, 2006 11:43 am Post subject: fluid level sensor needed

 	  Quote: 	
		   How much space do you have to work with?  Maybe you could use a

 float-type fuel level sensor and shorten the arm so that it fits inside

 the reservoir.


	


The tank is 4"x4"x3" so there is not a lot of space.



It will be a "zero pressure" system, or very low pressure.



Thanks,

Mickey



-- 

Mickey Coggins

http://www.rv8.ch/

#82007 finishing

do not archive

_________________
Mickey Coggins
http://www.rv8.ch/

Mark Phillips in TN

Joined: 10 Jan 2006
Posts: 431
Location: Columbia, TN

Posted: Thu Feb 16, 2006 12:01 pm Post subject: fluid level sensor needed

Have you taken a look at McMaster Carr?



click on:  http://www.mcmaster.com/

and go to page 490- they have several pages of float switches for many uses.  

Good folks to deal with- they sell a LOT of RV parts!



Mark Phillips

_________________
From The PossumWorks...

rondefly(at)rtriano.com
Guest

Posted: Thu Feb 16, 2006 12:22 pm Post subject: fluid level sensor needed

You could use the fuel warning system, I am using it on my header tank when

it is low. It should work in the Rad also. Here is the ACS #,  P/N 6905-400

$28.70



Ron Triano

http://bld01.ipowerweb.com/contentmanagement/websites/rtrianoc/page10.html

--

rv8ch

Joined: 10 Jan 2006
Posts: 250
Location: Switzerland

Posted: Thu Feb 16, 2006 1:58 pm Post subject: fluid level sensor needed

 	  Quote: 	
		   Have you taken a look at McMaster Carr?

 

 click on:  http://www.mcmaster.com/

 and go to page 490- they have several pages of float switches for many uses.  

 Good folks to deal with- they sell a LOT of RV parts!


	


Oh, yes, I know McMaster-Carr, as does my credit card.



I could only find on/off switches there, no analog switches.



I might have to punt on this and just go with a NO/NC

type switch.  Perhaps I'm trying to get too fancy.



Thanks for all the suggestions!



-- 

Mickey Coggins

http://www.rv8.ch/

#82007 finishing

do not archive

_________________
Mickey Coggins
http://www.rv8.ch/

Earl_Schroeder(at)juno.co
Guest

Posted: Thu Feb 16, 2006 2:25 pm Post subject: fluid level sensor needed

If memory serves me correctly, Jim Weir had a 'cheap' do it yourself 

capacitance probe and op amp amplifier project several years ago.  You 

might search his site.  Or the publication KitPlanes archives.  Earl

do not archive

Mickey Coggins wrote:

 	  Quote: 	

> Have you taken a look at McMaster Carr?

>

> click on:  http://www.mcmaster.com/

> and go to page 490- they have several pages of float switches for many uses.  

> Good folks to deal with- they sell a LOT of RV parts!

>     

 Oh, yes, I know McMaster-Carr, as does my credit card.

 I could only find on/off switches there, no analog switches.

 I might have to punt on this and just go with a NO/NC

 type switch.  Perhaps I'm trying to get too fancy.

 Thanks for all the suggestions!

raymondj(at)frontiernet.n
Guest

Posted: Thu Feb 16, 2006 3:42 pm Post subject: fluid level sensor needed

Would it meet your needs to use 2 or 3 float switches with the floats set at 

different levels. The fluid level could be defined within a range based 

which switches are closed/open.



Good luck,

rayj



Original Message ----- 

From: "Mickey Coggins" <mick-matronics(at)rv8.ch>

To: <aeroelectric-list(at)matronics.com>

Sent: Thursday, February 16, 2006 12:27 PM

Subject: fluid level sensor needed

 	  Quote: 	
		   

 <mick-matronics(at)rv8.ch>



 Hi,



 I'm looking for a fluid level sensor that I

 will use in my Subaru engine cooling system.



 I've found lots of on/off switches that will

 tell me if there is coolant there or not, but

 does anyone know of a reasonably priced sensor

 that will give me analog output over a range

 of values?  Reasonably priced means to me

 something less than about $250.



 Thanks!

 Mickey

 -- 

 Mickey Coggins

 http://www.rv8.ch/

 #82007 finishing

mprather(at)spro.net
Guest

Posted: Thu Feb 16, 2006 3:53 pm Post subject: fluid level sensor needed

Capacitors require a fairly decent dielectric media for the

between-the-plates insulator.  Coolant isn't that (dielectric nor

insulating)...



 	  Quote: 	
		   

 <Earl_Schroeder(at)juno.com>



 If memory serves me correctly, Jim Weir had a 'cheap' do it yourself

 capacitance probe and op amp amplifier project several years ago.  You

 might search his site.  Or the publication KitPlanes archives.  Earl do

 not archive



 Mickey Coggins wrote:

> 

> <mick-matronics(at)rv8.ch>

>> Have you taken a look at McMaster Carr?

>>

>> click on:  http://www.mcmaster.com/

>> and go to page 490- they have several pages of float switches for

>> many uses.   Good folks to deal with- they sell a LOT of RV parts!

>>

>

> Oh, yes, I know McMaster-Carr, as does my credit card.

>

> I could only find on/off switches there, no analog switches.

>

> I might have to punt on this and just go with a NO/NC

> type switch.  Perhaps I'm trying to get too fancy.

>

> Thanks for all the suggestions!

Earl_Schroeder(at)juno.co
Guest

Posted: Thu Feb 16, 2006 4:42 pm Post subject: fluid level sensor needed

Not to be 'picky' here but insulated probes will measure a conductive 

liquid quite well... used a bunch back at GE.  Earl

do not archive



Matt Prather wrote:

 	  Quote: 	
		   

 Capacitors require a fairly decent dielectric media for the

 between-the-plates insulator.  Coolant isn't that (dielectric nor

 insulating)...



   

> 

> <Earl_Schroeder(at)juno.com>

>

> If memory serves me correctly, Jim Weir had a 'cheap' do it yourself

> capacitance probe and op amp amplifier project several years ago.  You

> might search his site.  Or the publication KitPlanes archives.  Earl do

> not archive

>

> Mickey Coggins wrote:

>     

>> 

>> <mick-matronics(at)rv8.ch>

>>

>>

>>       

>>> Have you taken a look at McMaster Carr?

>>>

>>> click on:  http://www.mcmaster.com/

>>> and go to page 490- they have several pages of float switches for

>>> many uses.   Good folks to deal with- they sell a LOT of RV parts!

>>>

>>>         

>> Oh, yes, I know McMaster-Carr, as does my credit card.

>>

>> I could only find on/off switches there, no analog switches.

>>

>> I might have to punt on this and just go with a NO/NC

>> type switch.  Perhaps I'm trying to get too fancy.

>>

>> Thanks for all the suggestions!

>>

>>

>>       

>

>

mprather(at)spro.net
Guest

Posted: Thu Feb 16, 2006 5:35 pm Post subject: fluid level sensor needed

Good point.  How tough is it to make a probe that doesn't leak too bad.. 

I guess leakage adds series R to the RC circuit, so probably isn't too

critical, though I think it will damp the oscillator circuit.



http://www.rst-engr.com/rst/articles/KP89SEP.pdf



Discussion on dielctric strength.



http://www.usm.maine.edu/~newton/Chy251_253/Lectures/Solvents/Solvents.html



http://www.clippercontrols.com/info/dielectric_constants.html



This is still going to be a challenge - the glycol to water ratio isn't

always going to be the same, and the dielectric strength of water varies

with temperature..



How about a little camera with a light that lets you actually see a sight

tube??    Put the sight tube for the coolant next to a sight tube for

the engine oil level.  Have the camera display to the cockpit on a little

LCD..



Or how about adapt a fishfinder - mount it in the bottom of a tube within

the reservoir - pointed up, with a little float in the top of the tube. 

The fishfinder will detect the distance between the sensor and the float. 

Might have to work on improving the shallow water resolution.

Regards,



Matt-

 	  Quote: 	
		   

 <Earl_Schroeder(at)juno.com>



 Not to be 'picky' here but insulated probes will measure a conductive

 liquid quite well... used a bunch back at GE.  Earl

 do not archive



 Matt Prather wrote:

> 

> <mprather(at)spro.net>

> Capacitors require a fairly decent dielectric media for the

> between-the-plates insulator.  Coolant isn't that (dielectric nor

> insulating)...

>> 

>> <Earl_Schroeder(at)juno.com>

>>

>> If memory serves me correctly, Jim Weir had a 'cheap' do it yourself

>> capacitance probe and op amp amplifier project several years ago.

>> You might search his site.  Or the publication KitPlanes archives.

>> Earl do not archive

>>

>> Mickey Coggins wrote:

>>

>>> 

>>> <mick-matronics(at)rv8.ch>

>>>

>>>

>>>

>>>> Have you taken a look at McMaster Carr?

>>>>

>>>> click on:  http://www.mcmaster.com/

>>>> and go to page 490- they have several pages of float switches for

>>>> many uses.   Good folks to deal with- they sell a LOT of RV parts!

>>>>

>>>>

>>> Oh, yes, I know McMaster-Carr, as does my credit card.

>>>

>>> I could only find on/off switches there, no analog switches.

>>>

>>> I might have to punt on this and just go with a NO/NC

>>> type switch.  Perhaps I'm trying to get too fancy.

>>>

>>> Thanks for all the suggestions!

>>>

>>>

>>>

>>

>>

>>

>>

>>

>>

>>

>>

paul.mcallister

Joined: 09 Jan 2006
Posts: 177
Location: Waukesha, WI USA

Posted: Thu Feb 16, 2006 5:35 pm Post subject: fluid level sensor needed

Hi,



I built a fuel tank gauge based off a 0 ~ 1 " pressure transducer for my

Europa. Although you only have 0 ~ 4 " of head, I would say from my bench

experiments that this device is sensitive enough for your needs.



The sensor was a Honeywell 26PCAFA6D  and I amplified its output with a

INA118P instrumentation op amp.  It would cost you less than $25 in parts to

experiment with and I am confident that it would work for you.



Regards,  Paul

nuckollsr(at)cox.net
Guest

Posted: Sat Feb 18, 2006 2:49 pm Post subject: fluid level sensor needed

At 07:27 PM 2/16/2006 +0100, you wrote:



 	  Quote: 	
		  

<mick-matronics(at)rv8.ch>



Hi,



I'm looking for a fluid level sensor that I

will use in my Subaru engine cooling system.



I've found lots of on/off switches that will

tell me if there is coolant there or not, but

does anyone know of a reasonably priced sensor

that will give me analog output over a range

of values?  Reasonably priced means to me

something less than about $250.


	


   Does this need to be a quantity gage or just

   a low level warning?



   Bob . . .

rv8ch

Joined: 10 Jan 2006
Posts: 250
Location: Switzerland

Posted: Sat Feb 18, 2006 3:30 pm Post subject: fluid level sensor needed

 	  Quote: 	
		      Does this need to be a quantity gage or just

    a low level warning?


	


My goal is to know when it is low, but I don't

really trust an "idiot light" solution, which

is why I'd like some idea of the progression

from "ok" to "too low".



My fallback position is to install two on/off

type sensors at different levels, but that's

getting kind of kludgey.



Thanks for any hints!



-- 

Mickey Coggins

http://www.rv8.ch/

#82007 finishing

do not archive

_________________
Mickey Coggins
http://www.rv8.ch/

Larry McFarland

Joined: 10 Jan 2006
Posts: 36
Location: East Moline, Illinois

Posted: Sat Feb 18, 2006 4:47 pm Post subject: fluid level sensor needed

Bob,

I use a pressure sensor in a threaded boss in a metal hose connection. 

The warning is provided by

my Grand Rapids Technologies E I S.  It's alarm is set at a minimum 4 

psi.  You loose water pressure

you know just as well that you don't have enough water to continue much 

farther.  A low fluid level would

not necessarily save your engine if it were placed incorrectly and might 

be excess mechanics for what

you're trying to do.  A pressure switch is smaller and simpler to do.



Larry McFarland - 601hds with Stratus Subaru



Robert L. Nuckolls, III wrote:



 	  Quote: 	
		  



At 07:27 PM 2/16/2006 +0100, you wrote:



  



>

><mick-matronics(at)rv8.ch>

>

>Hi,

>

>I'm looking for a fluid level sensor that I

>will use in my Subaru engine cooling system.

>

>I've found lots of on/off switches that will

>tell me if there is coolant there or not, but

>does anyone know of a reasonably priced sensor

>that will give me analog output over a range

>of values?  Reasonably priced means to me

>something less than about $250.

>    

>

   Does this need to be a quantity gage or just

   a low level warning?



   Bob . . .

_________________
Larry McFarland - 601HDS - Stratus

rv8ch

Joined: 10 Jan 2006
Posts: 250
Location: Switzerland

Posted: Sun Feb 19, 2006 2:39 am Post subject: fluid level sensor needed

Hi Larry,



Thanks for getting back to me.



 	  Quote: 	
		   I use a pressure sensor in a threaded boss in a metal hose connection. 


	


Which pressure sensor are you using?



Paul's idea of using a Honeywell 26PCAFA6D amplified  with a

INA118P instrumentation op amp is great, but I'm not

really qualified to do that much integration.  I want

to run a zero pressure system, so using a sensor that

can detect such a small amount of pressure would be perfect,

assuming it's adequately damped.



 	  Quote: 	
		   The warning is provided by

 my Grand Rapids Technologies E I S.  It's alarm is set at a minimum 4 

 psi.  You loose water pressure

 you know just as well that you don't have enough water to continue much 

 farther.  A low fluid level would

 not necessarily save your engine if it were placed incorrectly and might 

 be excess mechanics for what

 you're trying to do.  A pressure switch is smaller and simpler to do.


	


I'm not planning to run any pressure in my system, but

this might change when my design meets reality.  Still, I'm

having a little trouble understanding the relationship between

pressure and coolant loss.  It seems like even if you have a

slow leak, and the coolant level goes down, the pressure

cap will maintain the correct pressure, even if it's only

air.  I'm kind of new to this, so please excuse my ignorance.



Thanks,

Mickey



-- 

Mickey Coggins

http://www.rv8.ch/

#82007 finishing

_________________
Mickey Coggins
http://www.rv8.ch/

Larry McFarland

Joined: 10 Jan 2006
Posts: 36
Location: East Moline, Illinois

Posted: Sun Feb 19, 2006 7:47 am Post subject: fluid level sensor needed

Mickey,

I used a Grand Rapids Technologies Part Number LPS-02 low pressure 

sensor suitable for fuel and coolant pressures between 0-28 psi.

My coolant pressure is always above 5 psi so the low warning is set at 4 

psi.  If you're using a zero-pressure coolant in your engine

like the Evans waterless coolants, this might not be a good idea as they 

only get pressure from pump flow.

GRT can be reached at Byron Center, MI ph 616-583-8000.

Larry

Mickey Coggins wrote:

 	  Quote: 	

Hi Larry,

Thanks for getting back to me.

>I use a pressure sensor in a threaded boss in a metal hose connection. 

>    

>

Which pressure sensor are you using?

Paul's idea of using a Honeywell 26PCAFA6D amplified  with a

INA118P instrumentation op amp is great, but I'm not

really qualified to do that much integration.  I want

to run a zero pressure system, so using a sensor that

can detect such a small amount of pressure would be perfect,

assuming it's adequately damped.

>The warning is provided by

>my Grand Rapids Technologies E I S.  It's alarm is set at a minimum 4 

>psi.  You loose water pressure

>you know just as well that you don't have enough water to continue much 

>farther.  A low fluid level would

>not necessarily save your engine if it were placed incorrectly and might 

>be excess mechanics for what

>you're trying to do.  A pressure switch is smaller and simpler to do.

>    

>

I'm not planning to run any pressure in my system, but

this might change when my design meets reality.  Still, I'm

having a little trouble understanding the relationship between

pressure and coolant loss.  It seems like even if you have a

slow leak, and the coolant level goes down, the pressure

cap will maintain the correct pressure, even if it's only

air.  I'm kind of new to this, so please excuse my ignorance.

Thanks,

Mickey

_________________
Larry McFarland - 601HDS - Stratus

nuckollsr(at)cox.net
Guest

Posted: Sun Feb 19, 2006 10:29 am Post subject: fluid level sensor needed

At 12:27 AM 2/19/2006 +0100, you wrote:



 	  Quote: 	
		  

<mick-matronics(at)rv8.ch>



 >    Does this need to be a quantity gage or just

 >    a low level warning?



My goal is to know when it is low, but I don't

really trust an "idiot light" solution, which

is why I'd like some idea of the progression

from "ok" to "too low".



My fallback position is to install two on/off

type sensors at different levels, but that's

getting kind of kludgey.



Thanks for any hints!


	


    Hmmmm . . . . but hard to beat for simplicity.

    Reed switches operated with magnets on floats

    are really inexpensive and reasonably reliable.

    There are some optical level sensors with

    possibilities. See:



http://www.gemssensors.com/electrooptical.htm



and



http://www.gemssensors.com/TOCResults.asp?nContentsID=29



    I'm working on a one wire, no moving parts, thermally

    sensed low liquid level detection system that will be

    simpler to install and still more rugged but no schedule

    on that activity yet. If you need something tomorrow,

    consider the technology cited above.



    For magnet and reed technologies, see:



    http://www.gemssensors.com/TOCResults.asp?nContentsID=36



    Some of these mount right through the sidewall of a

    container. You could install more than one and use

    simple indicator lamps to annunciate switch position.



    Bob . . .

rv8ch

Joined: 10 Jan 2006
Posts: 250
Location: Switzerland

Posted: Sun Feb 19, 2006 10:59 am Post subject: fluid level sensor needed

 	  Quote: 	
		       I'm working on a one wire, no moving parts, thermally

     sensed low liquid level detection system that will be

     simpler to install and still more rugged but no schedule

     on that activity yet. If you need something tomorrow,

     consider the technology cited above.


	


That sounds like a winner.  Please keep us posted.



 	  Quote: 	
		       Some of these mount right through the sidewall of a

     container. You could install more than one and use

     simple indicator lamps to annunciate switch position.


	


Looks like I need to modify the expansion tank drawing

I sent to Canton Racing to add a couple of 1/4" NPTs

onto the side.



Thanks,

Mickey



-- 

Mickey Coggins

http://www.rv8.ch/

#82007 finishing

do not archive

_________________
Mickey Coggins
http://www.rv8.ch/

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