PTS Flowbench Forum

65mustang393 wrote:Any word from Harold on SF calibration procedures? Did SAENZ just copy this procedure?

Other than price, are there any negatives to renting the box of SF cal plates and calculating what they should flow?

measuring flow using orifices has been around since the 1700's. There is a very deep rooted mathematical and scientific back ground for this. I personally would try and do my testing independantly from the source of the equipment, in this case SF. Not because they are bad, but because you are trying to find out if someplace in the whole system there is an ongoing error.

Buy or make a sharp edged orifice of a certain size that you know what the flow should be and flow it on your bench. If it flows what the orifice should be flowing then your bench is spot on. If your bench does not flow that value then your bench is off. It is that simple.

John

That's why I bought the PAP plates. The question is what's the right Cd and what are they really supposed to flow?

65mustang393 wrote:That's why I bought the PAP plates. The question is what's the right Cd and what are they really supposed to flow?

measure them and do the math.

Chad Speier wrote:

65mustang393 wrote:That's why I bought the PAP plates. The question is what's the right Cd and what are they really supposed to flow?

measure them and do the math.

Your opinion is duly noted and appropriately filed.

Gerald,

Ask Bruce if it is his plate he will tell yo the CD on top the bench at 28", they have been flowed enough times to validate the plates. We vary the CD on the internal sharp edge plate withing the PTS bench for calibration purposed.

The starting point is .58 the high end is .62.

your 2.044 300 plate is figured at 28" and a .6204 at Standard air.

Rick

1960FL wrote:Gerald,

Ask Bruce if it is his plate he will tell yo the CD on top the bench at 28", they have been flowed enough times to validate the plates. We vary the CD on the internal sharp edge plate withing the PTS bench for calibration purposed.

The starting point is .58 the high end is .62.

your 2.044 300 plate is figured at 28" and a .6204 at Standard air.

Rick

Crunching numbers now using the .6204 Cd.

Changed Cd to .62 based on post below.

PAP diameters are:

1.180
1.669
2.045

That being said there is a technique to measuring them so be very careful if you do measure them as you can and will damage the sharp edge and you will end up with a nick in them which would not be good!

They are machined to a 0.62 Cd based on a temp of 70 and a baro of 29.92". I do not use Rocco's spreadsheet for my math but it should be pretty close to his.

Let me also add my plates were never designed to be used as an "industry standard", I merely designed them to be used by the Average Joe who wanted to build an accurate repeatable flowbench. The Professionals got ahold of'em and here we are

Talk about a PITA! So I had to scour the net looking for an equation that was user friendly. Unit conversion and railroad tracks take me back to my Power School days...

I came up with (more like found) this.

http://gasho.org/rotron%20pages/orifice ... lation.htm

Q=AV
Q=cubic feet/min

V=CK x sq root of P
P=delta pressure

2.044" dia = 0.022787 sq feet = "A"
C= Cd = .62
K= 4005
P= 28" water pressure

"V" = .62 x 4005 x 5.2915 = 13139.32365 feet/min

Q=AV
Q=0.022787 sq feet x 13139.32365 feet/min = 299.4 cu feet/min

Brucepts wrote:PAP diameters are:

1.180
1.669
2.045

That being said there is a technique to measuring them so be very careful if you do measure them as you can and will damage the sharp edge and you will end up with a nick in them which would not be good!

They are machined to a 0.62 Cd based on a temp of 70 and a baro of 29.92". I do not use Rocco's spreadsheet for my math but it should be pretty close to his.

Let me also add my plates were never designed to be used as an "industry standard", I merely designed them to be used by the Average Joe who wanted to build an accurate repeatable flowbench. The Professionals got ahold of'em and here we are

Bruce, I measured as gently as I could with vernier calipers. I'm thinking that's not the preferred method... mind telling me how you recommend I measure the diameters?

Thanks,
Gerald

Yep and some believe (SF for example) that the cd stays constant at .60...

2.044" dia = 0.022787 sq feet = "A"
C= Cd = .62
K= 4005
P= 28" water pressure

"V" = .60 x 4005 x 5.2915 = 12715.474 feet/min

Q=AV
Q=0.022787 sq feet x 12715.474 feet/min = 289.75 cu feet/min

What did it flow??????????????????????????????????????????????????????????????????

Now do you want to know why the bench flows less than it should?