Annubar / Pitot Tube DP Calculator

[Weegie]

Can anybody point me in the right direction please of an annubar DP calculator in computer software/excel format.
I'm looking to check vendor's DP calculations(inches WC)against our given process flow data.

Many thanks.

 

[DRWeig]

Here's the data you need (attachement) to do your own, less your individual Annubar model's coefficien.

Good on ya,

Goober Dave

 

[Weegie]

Much obliged Dave.

Best regards.

Danny

 

[Weegie]

Just an update. One of our vendors (Endress & Hauser) directed me to an online interactive annubar calculator on their website.
Unfortunately, there's no direct link so, you have to drill down a little to find it.

 

[Niwot]

Hi Weegie,
In reference to your statement, "I'm looking to check vendor's DP calculations (inches WC) against our given process flow data", depending on to what degree of precision you're looking for, there is an issue to be aware of.

First, when you refer to "Annubar", confirm that an Annubar is exactly what you have. Also, you would need to know which model and sensor size (Diamond II, 485 etc.). Sometimes the industry - in general - refers to Annubars as a type of flow meter. It is actually a brand name that is unique to a single manufacturer. It's like asking for a Kleenex when you need a tissue.

An Annubar is an averaging pitot tube and it will have a flow coefficient (K) that is unique to the size and shape of the sensor. Other manufacturers of a similar device will have a different flow coefficient whether it be a diamond, round, bullet, T-shape, etc.

For reference I have attached 3 calculations and a flow curve. I took the flow coefficient from 3 random manufacturers and plugged them into our standard flow calculation program. I used 6" sch 40 pipe as the example. As you'll see there is quite a difference in DP produced at the max flow rate despite the fact that all other flowing conditions are the same (I used an air application as reference).

E+H and others have general sizing programs available, but the sensor flow coefficient (K) they use in their calculations will probably not be that of an actual "Annubar" but that of whatever Averaging Pitot manufacturer they are aligned with.

You should get a copy of the flow calc program from the actual manufacturer of the avg. pitot you have installed. It will save you alot of time in that you won't have to write your own program.

Since you mentioned an excel format, I have also attached a crude copy of a flow curve generated for a particular set of flowing conditions. You only need to pull certain info from your flow calc. (C' will be unique to the manufacturer), plug it into the excel program, and a curve with data points will be generated.

Since this forum is non-commercial, I have blacked out certain information on my attachments. Any avg. pitot tube manufacturer should be able to provide you a flow calc, their flow calc program, and/or a flow curve for your particular application. You should not have to generate a program yourself.

Just make certain that the corresponding flow coefficient for YOUR averaging pitot is used in your calculation. There are many avg. pitot brand names (including Annubar) and they all have different K's.

Sorry I caught onto this link late. Hope this is helpful.

Jake

 

[Weegie]

Jake,

much obliged for the guidance and info.
Having spoken with a couple of our vendors, they then made me aware of their website calculators for the annubars.

Best regards,

Danny

 

[knapee]

Is this Averaging pitot tubes or conventional pitot tube?

Averaging pitot tube preferred with a conventional pitot tube
cause it is difficult to determine the location along the pipe's diameter where the "impact opening" (measuring fluid
pressure plus velocity head) should be located.

 

[Weegie]

The annubars are 'averaging Pitot Tubes' (APT).