PTS Flowbench Forum

Hey guys first post on this forum and abit confused.. just bought a 2nd hand orifice type flow-bench. with vertical and incline manometer.. guy had a spreadsheet of sorts which he was suppose to supply. but alas he has passed away before i could get info on how it worked from him inculding the spreadsheet. well for starters hope you guys going bear with me i got a ton of questions...

1. As orifices guy was using digital cd media a cd basically cut with 2inch holes / 3inch holes.. etc... so i put this in the bench.. and on the top used another 2inch cd .. set test pressure to 6-inches on the scale which is in 1inch increments.. so if i understand this correctly. 6 inches of water rise on a 6 inches ruler is 12 inches of water correct?

2. how will i know what the cd type orifice flows been it 2inches in diameter.. as i will need to know this to work out my difference for cfm from incline manometer reading? or am i missing something...

3. how do i read my incline manometer? has a scale of 0-6 will attach pictures so u guys know what i am referring to..

sorry for been all over the place hope you guys understand all what i refer to this is my first time so just bear with me... I live in South Africa. and my area theres no one actually with flow benches for assistance even..

Welcome to the forum, found the right place!

1. Correct on the U-tube vertical manometer 6" rise and 6" fall is 12" total

2. Use the standard .62 for your Cd on the plates for now, would venture to say they will flex under pressure/airflow and your hole will go elliptical so it will mess with your Cd.

3. What is the rise of the incline not the length of the scale?

The forum members will help you narrow this down but it might be lots of questions in between

Brucepts wrote:Welcome to the forum, found the right place!

1. Correct on the U-tube vertical manometer 6" rise and 6" fall is 12" total

2. Use the standard .62 for your Cd on the plates for now, would venture to say they will flex under pressure/airflow and your hole will go elliptical so it will mess with your Cd.

3. What is the rise of the incline not the length of the scale?

The forum members will help you narrow this down but it might be lots of questions in between

Thank you for the warm welcome Bruce i feel brave to worry u guys with tons of questions now lol

Okay atleast i understand the vertical manometer for now...

2.. what do you mean use the standard .62 on the cd plates for now? they do flex under pressure but have a few supports a rubber seal holding them abit steady its how the bench came to me.. i will upgrade it as time goes on but a decent starting point for me now to under stand the basics..

3 .If i use a level from the bottom of incline to top reads roughly around 7.7 inches.. i can get this abit more accurate to what ever it needs be... advise here be appricaited.. i still do not understand that number 0-6 .. if its suppose to be in 0-100% the bench came to me this way.. added some more pics aswell.. of how i measured the rise of incline to verify if my method was correct.

4. added a few pics give u guys a better idea of whats going on.. please do not laugh at it that colour is hideous i know...

5. How will i know what the music cd type say 2inch orifice plate would flow? as i am going to need to know that to calculate my actual flow cfm.

Welcome to the Forum lovendhra.

With the sloping manometer, the important thing as Bruce has already said is the rise.
Basically the differential pressure drop across the flow measurement orifice raises the level of water in the sloping manometer.
If there is (for example) a four inch pressure differential, the water will travel along the sloping manometer until it reaches that four inch height.
The sloping manometer tube could be a foot long, three feet long, or any convenient length you wanted to make it.

The reason for doing it this way is that the scale can be made much longer and is much easier to read than a four inch high vertical manometer would be.

Just guessing here, but the 0 to 6 sloping manometer scale may correspond to 0 to 6 inches of vertical rise ?
While the whole tube length may have a 7.7 inch rise, check the vertical rise between "0" and "6" scale markings.

The vertical rise from 0-6 on the scale is 7inches.. but the incline manometer came of the board when delivery i just use masking tape and stuck it at the current position.. so if the scale reads 0-6 on incline manometer.. from how its been labelled the vertical rise should be 6-inches of the 0-6 scale?

The vertical rise from 0-6 on the scale is 7inches just measured it now.. but the incline manometer came of the board when delivery i just use masking tape and stuck it at the current position.. so if the scale reads 0-6 on incline manometer.. from how its been labelled the vertical rise should be 6-inches of the 0-6 scale?

I would say it is very likely that the original 0 to 6 markings were inches of rise.
There is not really any other logical explanation.

How long is the scale and the tube on the sloping manometer ?

0-6 markings = 18inches exactly. the fluid level on incline manometer sits @ 0 marking on scale...

That sounds logical.
It just means that the water travels three times as far for each inch of rise which makes the scale much easier to read.

Tony wrote:That sounds logical.
It just means that the water travels three times as far for each inch of rise which makes the scale much easier to read.

Sorry to ask this but. specifically what do you mean 3-times as far for each inch of rise.. each inch of rise on vertical manometer? or inch of physical rise on incline manometer.. incline sounds more the likely answer.. define 3 times as far.. sorry for the questions it may be silly.. tho i would rather understand it then just say okay

secondly regarding this round music cd type orifice that i am using.. how would i know the flow of a say 2-inch one that i have.. this is the 1 that fits in the bench.
as i am going to need to know this i assume to work out the cfm with say a 1.5 inch cd on the top of the bench. also when i am referring to cd its literally a music cd that came as a orifice for this bench.. not sure what Bruce meant when he said " Use the standard .62 for your Cd on the plates for now"