Manometers - Selection, application, etc...

[bruce]

A closeup:

[thomasvaught-1]

I did not racehead.

Send me a PM on this site.

Tom Vaught

[jfholm]

We have discussed at some length what fluid to use in our manometers. MMO at sg of .826 or DOT 5 silicone brake fluid at .989 ? I think or water at 1.00.

Here are some things I have noticed when using Ed's spreadsheet to calculate the Dp of the orifice you are using in your bench. The Dp gets higher with the SG being higher for the fluid you use, that is also a given as you have to suck harder to get the fluid to rise in the manometer the same distance as a lighter SG fluid.

So if you used a fluid that has a higher SG and your Dp of your orifice is higher that means you can use smaller orifices in your bench to get a higher CFM reading when using the same inclined manometer. As an example with my manometer, id on the tubing is .250" and the reservoir id is 1.430", 12" rise with MMO the Dp is 10.82 and with the DOT 5 the Dp is 12.96

So with MMO a 300 cfm orifice would need to be 2.615" diameter and with DOT 5 a 300 cfm orifice would need to be 2.499" diameter. This may help on the exhaust flow accuracy where the orifice is getting close to the size of the hole in the divider between the chambers. With the higher SG fluids you can use a smaller orfice.

I am even considering a heavier fluid for the manometer.

John

[jfholm]

Has anyone that is using water in their manometers used the anti-spotting agent/Dry liquid for dishwashers added to the water? It seems to make the water run off the dishes when washing to keep them from spotting. I was wondering if anything like that would work?

Maybe I could coat the inside of my manometer tubing and reservoirs with RainX?

John

[86rocco1]

Somebody gave me some surfactant that's used in the preparation of commercial grade dishwasher liquid, it's called Plurafac SLF-18 made by BASF. It's non-foaming and it seems to reduce the surface tension of the water a fair bit, it hasn't seen much use but so far so good.

As far as dishwasher drying/rising agents go, try it out, maybe make a manometer out of some scrap tubing just to see if you like how the liquid behaves.

[slracer]

Ed, I just took a look at the website for Plurafac and they have an "advisory" posted about keeping it warm.



Have you had any problems?

Doug

[86rocco1]

It just gets cloudy when it's cold, doesn't seem to affect the product otherwise and it clears right up again when you warm it.

[Colby]

400 seems alitle high,ie got an account with dwyer ill see what $$$ i can get you one for.PM me if your intrested

[49-1183904562]

See the Pts-DM has the Surfactant built in :p
No SG Problem,
No wetting agents,
No Expensive fluids to get blown on the shop floor,
No conversion scales.
Must i go on?

Sorry guys I could not help myself.

Rick

It's a bargin and even works in the kitchen John

[msj442]

i didnt have to experience these joys of manometers as i went with the pts dm. it is an amazing product,affordable,and simple. thats the best thing.

jmo,max

[Tony]

[jfholm]

But that is how I get my heads to flow a lot of air, I tilt the bench :;):

John