Glad I could help! Make sure you get one like mine with a long neck. More accurate for this type of sample. Mine is the .3 meter insertion size: dwyer-inst.com/series-160e.html
@stuntr1 you don't have to, just take your orifice out and use it. When your doing the qualification your sampling airflow upstream of the orifice so it doesn't effect the test. Also, one thing I did not mention, make sure you abide by the minimum duct diameters when drilling your test holes. This allows the air to settle as much as possible before getting to the tip of your pitot tube. Read this: www.google.com/url?sa=t&source=web&rct=j&url=dwyer-inst.com/PDF_files/H_12_A_rev1.pdf&ved=2ahUKEwjh4Y6khpT9AhW7l2oFHYx2DU4QFnoECBEQBg&usg=AOvVaw2xoKdBLnA-jP86AQsrEiAb
From 0:30-0:39 you state you need two orifices, and you are using 3". On another video, you stated you could run it from 6" all the way! Is it necessary to use two identical orifices to be accurate (one at your differential measuring point, and one post-cylinder head)?
You don't have to have two, its just convenient. You could uninstall the orifice you are using and place it on the bore plate in place of the cylinder head. The purpose of using the orifice is to know how much cfm the orifice is flowing at a specific pressure drop using the pitot tube. Once you know what it flows you reinstall the orifice and then go testing. The downstream orifice plays no role in the test, so it doesn't need to be there. Make since? Only need one orifice for the test.
@tristan_white perfect. I had some big confusion with that! Qualify with it. Test with whatever you want in a way lol. I think I'm going to use 4" PVC with a 3" orifice! I'm 3d printing my plates.
@donaldlee255 you need to qualify the bench with the exact same orifice that you will use to do your testing. Just make sure that when you use the pitot tube that it is setup properly for your inside diameter pipe.
The red gauge oil has a specific gravity of ~.86 (less than water) this requires the fluid to move at a greater displacement for the same given pressure. It helps to see small changes, but no you don't have to do it. It just helps with accuracy.
@@tristan_white ok thanks. Just to make sure, the sharp edge of the orifice plate faces the vacuum motors correct? If it was backwards , would it skew the numbers?
Absolutely, if you use a larger orifice the process is the same, you will just not need to run the test pressure so high. That's all Superflow does on their benches. When you swap "scales" on their bench you are just swapping to a different size orifice. Whatever orifice gets you to ~70% of flow is the most accurate.
Finally received my pitot tube and flowed my bench but on of the holes flows way different to the other hole 90degrees away. Is this normal? One is like 380cfm average for 10 traverses and the other hole the averages go up to 480cfm
Yes, there will typically be some differential flow. Flow is not going to be perfectly laminar, so that is why it is so important to get 10 repeatable timed traverses (more if needed), then average the two numbers. If you are testing too close to a bend in the pipe you will see a larger delta like you are. Just make sure you are consistent on how you are gathering your samples. 10 sec timed traverse as many times as you need to get a good number. If it seems way off what it should be than move your sample spot further away from the pipe bend or add a flow straightener in the pipe upstream of the sample point to assist.
@@tristan_white I’m actually about 4 feet away from the bend and closer to the vacuum pumps . I have since gotten around 430cfm consistently from one hole and 388cfm from the other now. My orifice was labeled from PTS as a 2.933” orifice flowing 350 at 9” water. Can my readings be correct . I’ve taken 10 samples each side
@stuntr1 it is absolutely possible. Mine said the same, but flows 375cfm @ 9"H2O. This is why it is critical to qualify it yourself. If you have the settings in the testo correct for diameter, ambient temperature, and atmospheric pressure correct for where your bench is, and you are getting back to back consistent readings then it is correct. If your skeptical then ensure you are 100% perpendicular to the flow the entire traverse not biased to one side or the other and tip is pointed correctly. Flow tends to be the greatest near the wall due to frictional turbulance in the boundary layer. Also make sure your test piece orifice is not leaking by (sealed with vasoline or something and clamped down tight), is as close to the wall away from where your taking the test pressure readings (this will effect your 9"H2O test pressure accuracy), and you zero out the meter once the pitot tube is inside the pipe.
@@tristan_white is there a way to calibrate a u-type home made nanometer ? I have a 48” ruler with the tubes filled to 24” mark with water at rest . Does it matter how much water is in the hose or just the difference in inches when it’s in use
@stuntr1 as long as it is straight and using normal water it won't matter. The total displacement is all that matters. As long as it is very steady and not bouncing around you should be good. If it is bouncing around you likely have turbulance in front of the test line and that will kill the accuracy.
Thank you for this video. Ill have to purchase a pitot tube to qualify my bench
Glad I could help! Make sure you get one like mine with a long neck. More accurate for this type of sample. Mine is the .3 meter insertion size:
dwyer-inst.com/series-160e.html
@@tristan_white my orifice says 3.933 inch. Should I get a similar size hole machined in another plate for the bench qualifying
@stuntr1 you don't have to, just take your orifice out and use it. When your doing the qualification your sampling airflow upstream of the orifice so it doesn't effect the test. Also, one thing I did not mention, make sure you abide by the minimum duct diameters when drilling your test holes. This allows the air to settle as much as possible before getting to the tip of your pitot tube. Read this:
www.google.com/url?sa=t&source=web&rct=j&url=dwyer-inst.com/PDF_files/H_12_A_rev1.pdf&ved=2ahUKEwjh4Y6khpT9AhW7l2oFHYx2DU4QFnoECBEQBg&usg=AOvVaw2xoKdBLnA-jP86AQsrEiAb
2.933" sorry
When your doing this is the original orifice in place or is the original orifice place at the test head?
It would be removed and placed on the bench as if it were the head as shown.
From 0:30-0:39 you state you need two orifices, and you are using 3". On another video, you stated you could run it from 6" all the way! Is it necessary to use two identical orifices to be accurate (one at your differential measuring point, and one post-cylinder head)?
You don't have to have two, its just convenient. You could uninstall the orifice you are using and place it on the bore plate in place of the cylinder head. The purpose of using the orifice is to know how much cfm the orifice is flowing at a specific pressure drop using the pitot tube. Once you know what it flows you reinstall the orifice and then go testing. The downstream orifice plays no role in the test, so it doesn't need to be there. Make since? Only need one orifice for the test.
@tristan_white perfect. I had some big confusion with that! Qualify with it. Test with whatever you want in a way lol. I think I'm going to use 4" PVC with a 3" orifice! I'm 3d printing my plates.
@donaldlee255 you need to qualify the bench with the exact same orifice that you will use to do your testing. Just make sure that when you use the pitot tube that it is setup properly for your inside diameter pipe.
Is it necessary to use the dwyer gauge fluid over regular dye for the manometer?
The red gauge oil has a specific gravity of ~.86 (less than water) this requires the fluid to move at a greater displacement for the same given pressure. It helps to see small changes, but no you don't have to do it. It just helps with accuracy.
@@tristan_white ok thanks. Just to make sure, the sharp edge of the orifice plate faces the vacuum motors correct? If it was backwards , would it skew the numbers?
@stuntr1 yes likely (although probably small), place it in the same direction of the flow as it is installed on the bench for sake of consistency.
This one would work? The Dwyer pitot tubes are fairly expensive
@@stuntr1 don't see a link or description?
Is there any merits in changing the orifice size? E.g. test pressure increase verse orifice diameter increase.
Absolutely, if you use a larger orifice the process is the same, you will just not need to run the test pressure so high. That's all Superflow does on their benches. When you swap "scales" on their bench you are just swapping to a different size orifice. Whatever orifice gets you to ~70% of flow is the most accurate.
Finally received my pitot tube and flowed my bench but on of the holes flows way different to the other hole 90degrees away. Is this normal? One is like 380cfm average for 10 traverses and the other hole the averages go up to 480cfm
Yes, there will typically be some differential flow. Flow is not going to be perfectly laminar, so that is why it is so important to get 10 repeatable timed traverses (more if needed), then average the two numbers. If you are testing too close to a bend in the pipe you will see a larger delta like you are. Just make sure you are consistent on how you are gathering your samples. 10 sec timed traverse as many times as you need to get a good number. If it seems way off what it should be than move your sample spot further away from the pipe bend or add a flow straightener in the pipe upstream of the sample point to assist.
@@tristan_white I’m actually about 4 feet away from the bend and closer to the vacuum pumps . I have since gotten around 430cfm consistently from one hole and 388cfm from the other now. My orifice was labeled from PTS as a 2.933” orifice flowing 350 at 9” water. Can my readings be correct . I’ve taken 10 samples each side
@stuntr1 it is absolutely possible. Mine said the same, but flows 375cfm @ 9"H2O. This is why it is critical to qualify it yourself. If you have the settings in the testo correct for diameter, ambient temperature, and atmospheric pressure correct for where your bench is, and you are getting back to back consistent readings then it is correct. If your skeptical then ensure you are 100% perpendicular to the flow the entire traverse not biased to one side or the other and tip is pointed correctly. Flow tends to be the greatest near the wall due to frictional turbulance in the boundary layer. Also make sure your test piece orifice is not leaking by (sealed with vasoline or something and clamped down tight), is as close to the wall away from where your taking the test pressure readings (this will effect your 9"H2O test pressure accuracy), and you zero out the meter once the pitot tube is inside the pipe.
@@tristan_white is there a way to calibrate a u-type home made nanometer ? I have a 48” ruler with the tubes filled to 24” mark with water at rest . Does it matter how much water is in the hose or just the difference in inches when it’s in use
@stuntr1 as long as it is straight and using normal water it won't matter. The total displacement is all that matters. As long as it is very steady and not bouncing around you should be good. If it is bouncing around you likely have turbulance in front of the test line and that will kill the accuracy.