Would appreciate some help on the following:
Creating a Macro that uses the Excel "Solver" function. When I run the Macro it returns with a notice
"Compile error:
Sub or Function not defined."
It highlights "SolverOK" in the code.
If someone could sugest a solution it would be appreciated...
Have a look at the Yarway valves. They were made for these application.
If you use an RO on its own for min flow, you will have to add this flow rate into your requirements for your process design flow rate.
http://www.yarway.com/control_valves.asp
AS you wish to maintain a 50 PSI drop across the particular system the best approach is to use a feedback loop and measure that D/P. Thus a D/P transmitter across the system or two pressure transmitters.
It would appear that the system has a fixed resistance and by maintaing the 50 PSI drop one...
One should draw a diagram for the system. In the best case, once the line is filled the lowest pressure that could be achieved at the top of the hill is zero PSIA. That would be equivalent to 33.9 ft of water at 4C at sea level. Since it appears that you have a heavier fluid the head in feet of...
See "Chemical Engineering Fluid Mechanics", by Ron Darby. In the second ed., it is explained on page 218, Unknown Diameter. However, no name is given to the dimensionless number.
Although, it remains a trial and error approach.
Orifice Sizing
I used the method given in Flow Measurement Engineering Handbook in Chapter 13.(Third Edition). My values differ by the difference in the discharge coefficient that have been used. The method is for a plate with d<thickness<6d.
The fly in the ointment for me is the assumption...
I would suggest that the "relief" valve is operating correctly and that perhaps the air supply system is set too high for the downstream service.
If it is a case where the normal operation is lifting the safety valve then the upstream conditions should be changed to prevent the overpressuring...
Just to add a bit.
Richard W. Miller's book "Flow Measurement Engineering Handbook" discusses this in chapter four, titled Accuracy.
One way that I thought about this, is in addition to the normal errors as covered in the above methods, is to do a calculation for the additional error from the...
The max possible error for each device is addded together as an absolute value. Thus your orifice, flow transmitter and recording device are all added together. This will give you the max possible error when conditions are as per the orifice calculations. Depending on the P & T calculations that...
Here is an MSDS for your substituted benzine derivative.
http://physchem.ox.ac.uk/MSDS/XY/o-xylene.html
Having been involved in a BTX plant years ago, I am surprised that these things are still connected to the atmosphere.
No. Your method is correct.
I do not get the same Re in your calculation.(Assuming the flow was in GPM)
For your own calcs write down the inputs and stay with those same values throughout.
I am not checking all simple calcs. I have been working from your inputs.
In a few years from now if...
OK
I checked the Crane reference.
Your value for K contains an error for "d".
You repeated the error for "d" in the calculation for delta P.
Hope that this helps a bit.(My comments pertain only to delta P calcs.) Aparently you have changed to 1/2".
If 1/2" is used Re changes and just by chance...
OK
I get the same Re and the same f
However, I do not get the same delta P. I looked in Crane and could not find the equation that you have used for your delta P calc.(0.1PSI)
Or list the reference for your delta P calculation.
RJB32482
Your units for flow rate are mixed up.
Your origional post has 0.8 GPH
Your last calculation has 0.35GPH for the Re calculation.
Your delta P calculation has 0.35 GPM.
A good way of checking things is to make sure that the units come out correctly. Otherwise you might not be off by...
From a practical standpoint I would say yes, because it will not result in a large pressure drop. However, the plots of f vs Re that I have seen normally end around Re = 100.
So you Darcy-Weisbach f would be correct.
Just a further note, I obtain a Re of about 0.1 for your conditions, assuming...
Just happened upon this post and have to comment. I have no expertise nor experience in HVAC other than living in a cold climate.
Looking at the pictures and reading the comments it has not been stated whether there is a fresh air intake for combustion. If not there shoud be one for safety.
It...
As always language has a huge effect on things.
I don't know the full background on how the language for control valves has developed but my two cents on the wording for this is, that it is at the least confusing.
Perhaps a better definination for max allowable dP would be max effective dP. In...
One that I am using at present is "Chemical Engineering Fluid Mechanics", Second Edition by Ron Darby.
Another one, which I have only scanned through and followed some examples is "Slurry Systems Handbook" McGraw Hill.
Depending on the case they require knowing the limits and possible range...
