how to calibrate my bench with pts orifice plates

[PM308]

hi guys i new to this forum and i have a few questions i hope im in the right area please bear with me if im not

i have a FME600 flow bench made here in australia it uses a external orifice like a SF110 but i have 2 ranges 100cfm and 600cfm
the oriface is rectangle and it uses a slide to lengthen the orifice for 100 to 600cfm ranges the 600 range will flow down as low as 40cfm

anyway the bench has no water manos and just uses port flow analyzer black box and software, the bench is very repeatable it has 6 motors and variable speed for the motors so it has no flow control valve just a dial

anyway my question is how to calibrate it using pts plates, the bench has a 558.4cfm calibration plate but its only plastic and it is not a sharp edge orifice

i recently borrowed a set of pts plates off a friend and i would like to use these to calibrate, i have flowed all 10 plates on my bench

my first question is this do i have to flow the plates straight on the bench with no head adapter or on the head stand, the head stand has a 4.500 bore without the bore adapter sleeves, the reason i ask is i get a fairly big difference between flowing them on the head stand and flowing them straight on top of the bench

2nd question is i mainly want to check my readings at 300cfm, what cfm should i see with the 300cfm plate, when i flow it on the bore adapter i get 307cfm when i flow it on the bench alone it flows 301cfm but my friend rekons on his bench with a fp1 it flows 292cfm so it looks like im showing high

the 600 cfm plate flows 611cfm on the bench alone

can anybody tell me what cfm i should see with these plates as i can just adjust my correction factor to match the correct flow with that plate

any help would be much appreciated.

[Brucepts]

Flow the plate bevel side down right on top of your flowbench, no bore adapter.

What they are marked on the label is what they are rated to flow.

Can you take some pics of your flowbench and post'em??

[larrycavan]

http://www.flowbenchoz.com/FM600.htm

[larrycavan]

hi guys i new to this forum and i have a few questions i hope im in the right area please bear with me if im not

i have a FME600 flow bench made here in australia it uses a external orifice like a SF110 but i have 2 ranges 100cfm and 600cfm
the oriface is rectangle and it uses a slide to lengthen the orifice for 100 to 600cfm ranges the 600 range will flow down as low as 40cfm

anyway the bench has no water manos and just uses port flow analyzer black box and software, the bench is very repeatable it has 6 motors and variable speed for the motors so it has no flow control valve just a dial

anyway my question is how to calibrate it using pts plates, the bench has a 558.4cfm calibration plate but its only plastic and it is not a sharp edge orifice

i recently borrowed a set of pts plates off a friend and i would like to use these to calibrate, i have flowed all 10 plates on my bench

my first question is this do i have to flow the plates straight on the bench with no head adapter or on the head stand, the head stand has a 4.500 bore without the bore adapter sleeves, the reason i ask is i get a fairly big difference between flowing them on the head stand and flowing them straight on top of the bench

2nd question is i mainly want to check my readings at 300cfm, what cfm should i see with the 300cfm plate, when i flow it on the bore adapter i get 307cfm when i flow it on the bench alone it flows 301cfm but my friend rekons on his bench with a fp1 it flows 292cfm so it looks like im showing high

the 600 cfm plate flows 611cfm on the bench alone

can anybody tell me what cfm i should see with these plates as i can just adjust my correction factor to match the correct flow with that plate

any help would be much appreciated.

Some thoughts based on what's in this post:

It sounds to me like the range selector is a sliding plate arrangement. It simply enlarges or reduces the area available to measure the Dp that gets calculated into CFM. SF does that short of thing with the 1020 bench. Here are some things to consider regarding a 2 range setup that is designed like that.

First, in normal calibration process, we adjust the Cd of the orifice plate inside the bench to achieve our calibration plate rating. That said, let's look at the 600 range results you've gotten so far.

300 Cal - 301 Reading
600 Call - 611 Reading - 1.8% variance [within Super Flow acceptability standards]

Based on how I "think" this thing functions, I don't see how you can adjust Cd on of the measuring orifice to suit both the 300 and 600 cal plates. They're both using the same range of the bench.

Since you have a 100 range and the 600 range is good down to 40CFM, if you have a 100CFM cal plate, compare it using both ranges and see what the results are.

A mechanically adjustable range that functions by area reductions or increases, would be a very, very touchy arrangement.

As it stand from you initial results here, I personally feel you're in pretty good shape. What you might want to do for comparability purposes is to work with your friend to try to dial your two benches in so they read as closely to each other as possible. As it is, they're pretty close on that 300 plate from a [+/-} percentage perspective, assuming he got 292 on a 600CFM range and the cal plate is actually rated 300CFM.

When comparing numbers between each other, look at the incremental lift increases / decreases as your indicator rather than focusing all the attention on the CFM total difference. In other words, if his bench read 400CFM as the peak flow and yours read 410CFM, the important comparable numbers would be what CFM increases or decreases did you see at each lift increment. Did each bench gain or loose an equal amount....

Perfect....hell no.. but you're in the ball park by a long margin. A winning head on Sunday is a still a winning head if it's removed from the engine on Monday, flowed on 5 different benches and yields 5 different CFM results [within reason].

JMO

[1960FL]

have a FME600 flow bench made here in australia it uses a external orifice like a SF110 but i have 2 ranges 100cfm and 600cfm
the oriface is rectangle and it uses a slide to lengthen the orifice for 100 to 600cfm ranges the 600 range will flow down as low as 40cfm

Does your black box compensate for Temp, Elevation, Barro etc.? As this will have an effect on your numbers.

Rick

[PM308]

thanks for the quick response guys, i will get some pics up here but basicly its the same as the one you see in link larry put up here, notice the orifices on the side for int and ex

larry i see what you mean about trying to calibrate two different plates on the same range, i was thinking of adding another range but like you said this would be very tricky, in regards to the difference between benches through the range i will compare the numbers for the 10 plates again and see if the difference is constant or not,

the main problem i have noticed with my bench is that cfm will vary depending on which motors i have on, once motors # 4, 5, 6 are switched on i get a 4cfm increase when flowing around 300cfm and i think this may be due to the placement of the pressure pickup so i am thinking i need to do my calibrating with all motors switched on and just flow test with all 6 on and adjust test pressure with the speed control instead of only using enough motors to achieve 28", in the past i have just been switching on motors extra motors at certain lifts eg 2 motors up to 200 lift then 3 motors at 300, then if flow is going to be above 300cfm i will switch on the 4th motor at 500 lift, that way it is easy to remember when comparing old tests.

i think if run all 6 then this should not be a problem, what do you guys think about this problem?


RICK, the bench uses temperature correction but has no baro sensor.

[larrycavan]

thanks for the quick response guys, i will get some pics up here but basicly its the same as the one you see in link larry put up here, notice the orifices on the side for int and ex

larry i see what you mean about trying to calibrate two different plates on the same range, i was thinking of adding another range but like you said this would be very tricky, in regards to the difference between benches through the range i will compare the numbers for the 10 plates again and see if the difference is constant or not,

the main problem i have noticed with my bench is that cfm will vary depending on which motors i have on, once motors # 4, 5, 6 are switched on i get a 4cfm increase when flowing around 300cfm and i think this may be due to the placement of the pressure pickup so i am thinking i need to do my calibrating with all motors switched on and just flow test with all 6 on and adjust test pressure with the speed control instead of only using enough motors to achieve 28", in the past i have just been switching on motors extra motors at certain lifts eg 2 motors up to 200 lift then 3 motors at 300, then if flow is going to be above 300cfm i will switch on the 4th motor at 500 lift, that way it is easy to remember when comparing old tests.

i think if run all 6 then this should not be a problem, what do you guys think about this problem?


RICK, the bench uses temperature correction but has no baro sensor.

Sounds like a good approach

[PM308]

i checked the plates on the bench again today and changed correction factor until the 300 plate flowed 292cfm this appears to be around the average number on other benches

plates were flowed straight on the bench the numbers are below how do these numbers look

1. 98.0
2. 147.3
3. 193.2
4. 241.1
5. 292.1
6. 341.5
7. 388.2
8. 437.1
9. 486.7
10. 587.4

same plates on a sf1020

1. 101
2. 149
3. 194
4. 243
5. 293
6. 341
7. 387
8. 439
9. 486
10. 585

SF600

1. 97
2. 147
3. 195
4. 238
5. 285
6. 337
7. 382
8. 438
9. 484
10. 576

with this test i just turned on one motor at a time to achieve 28" test pressure, when i tried all 6 motors on plate one it flowed 109cfm so there must be an issue with placement of the pressure pickup in relation to the motors,

strangely it was close to the 1020 using only the required motors to achieve 28" i dont know if this is just a fluke it turned out that way maybe i should just leave the bench alone,

the next thing i need to do is test the plates on the head stand as i have figures for the plates on head stand for the 600 and the 1020

[1960FL]

I would leave it alone this is just again another example of the issue with the SF600 on high end flow, if you want more confirmation follow Chad’s thread.

http://www.flowbenchtech.com/forum/view ... ?f=5&t=458


Rick

[larrycavan]

Here's the Standard Deviations between the benches. Look at the SF600....again