Tying in a chlorine residual analyzer to a VFD metering pump
Tying in a chlorine residual analyzer to a VFD metering pump
(OP)
I would like to know what would be the most proficient way to set up a Hypo injection system utilizing a chlorine residual analyzer and a Variable Frequency Drive(VFD) pump. The current system utilizes the VFD metering pump (metered according to flow rate); however, I believe that tying in a chlorine residual analyzer will be a much more effective method to control the VFD according to chlorine residual. Any suggestions would be appreciated.
Thank You.
Thank You.





RE: Tying in a chlorine residual analyzer to a VFD metering pump
You would need a VFD with PI or PID Closed Loop capability.
Then you would need to provide it with an adjustable setpoint that is scaled in proportion to the units of applicability.... i.e. PPM, etc ...
for analog... 0-10v 10v = xx PPM
or analog ..... 4-20mA 20mA = xx PPM
or digital setpoint capability within the VFD and scaling capability of the feedback.
Next, the Chlorine Analyzer must be able to provide a feedback of the correct proportionality to match the setpoint range.
ex. analyzer provides output range 0-10v where 10v = xx PPM, etc...
Next you would need to be able to adjust the response of the closed loop to accommodate the transport delay of the analyzer. Transport delay is the the time that it takes to report a change, once a change has been made.. This could be anywhere from milliseconds...to seconds.... to minutes... depending upon how fast the selected analyzer processes a sample and how many samples are required to arrive at the correct measurment.
And you would need to correlate metering pump flow... to PPM ....
That's the basic framework.
jO
RE: Tying in a chlorine residual analyzer to a VFD metering pump
RE: Tying in a chlorine residual analyzer to a VFD metering pump
I think that Don succinctly stated that it was a metering pump being operated by the VFD.
Metering Pumps are NOT Booster pumps, JB.
In this type of application, JB.... there isn't any call for a "Booster Pump".... there is no need to increase the flow or the pressure.
What is required is to meter the amount of chlorine being added to the process.
It is basically, a very simple system, JB.
RE: Tying in a chlorine residual analyzer to a VFD metering pump
RE: Tying in a chlorine residual analyzer to a VFD metering pump
1. Theodore Baumeister "Mark's Standard Handbook for Mechanical Engineers," 8th Edition, McGraw-Hill Book Co., 1978, page 16-17
The metering pump is an accurately calibrated positive-displacement pump which provides both measurement and control of fluid-flow rate. Obviously, the control implies reduction of the flow as well as boosting.
RE: Tying in a chlorine residual analyzer to a VFD metering pump
http://www.instrument.org/res.htm
http://www.instrument.org/Article_CompndCosts.htm
(notice special sample pumps there)
http://www.controlmagazine.com/Web_First/ct.nsf/ArticleID/PSTR-54EQ9G/
http://www.dkktoa.net/news4.html
http://sgcbookstore.safeshopper.com/78/12.htm?427
http://www.yokogawa.com/cms/com/ep/contentView.do;jsessionid=1mqrQoOSVFO77ztj2NIgx1vcOGXqDStikyIV9kOM4p1DwuAeRkW2!-733665846?contentType=LIST_VIEW_CONTENT&programId=10307&programPage=%2Fyokogawa%2Fia%2Fan%2Fhtml%2Fchlorine%2Fan-chlorine-001en.htm&contentId=536881614&pageTypeId=10047&channelId=-9754¤tSubFamily=Residual+Chlorine+Analyzer+RC400G¤tPageNo=1
http://www.capitalcontrolsindia.com/pg01.htm
http://www.gliint.com/catalog/pdf/data/ds-accl2.pdf
http://www.ryanherco.com/Industries/VendorArticles/Walchem/ChlorineDisinfectionControl.pdf
(for a choice of methods)
Please, also try Civil/Environmental Engineering Forum
e.g.
http://www.eng-tips.com/viewthread.cfm?spid=164&newpid=164&sqid=64180
RE: Tying in a chlorine residual analyzer to a VFD metering pump
RE: Tying in a chlorine residual analyzer to a VFD metering pump
RE: Tying in a chlorine residual analyzer to a VFD metering pump
I'm curious: How would you do that in a Closed Loop system with a diaphragm type pump... i.e. how would you control the stroke and the number of strokes per minute... in a closed loop system with the analyzer as an integral part of the loop.
Suggestions .... ? ? ? ?
RE: Tying in a chlorine residual analyzer to a VFD metering pump
I give up. My explanation on this to you will be like translating a Chinese literary work into German commoners language (funnily I don't know both the languages). I took all the sarcasm and still, no crossing swords (coz you sure are an expert guy - ref. your previous posts)
What I intended to mean is a pump driven by a solenoid and not by motor. Prominent is the manufacturer of these pumps and we did this for one of our water treatment plants.
Next time, I think, I should restrict myself from generalizing a specific thing
Sincerely,
RE: Tying in a chlorine residual analyzer to a VFD metering pump
You almost got it right;
"Obviously, the control implies reduction of the flow as well as boosting."
Not really, JB.
Here are a couple of definitions for you:
1. from Webster's New World Dictionary ...
Booster..... an auxiliary device for increasing force, power, pressure, or effectiveness.
2. from Vicker's Hydraulic Handbook...
At a given speed, Positive Displacement pumps deliver constant volume {flow} independent of discharge pressure.
NO BOOSTING, JB.
Metering Pumps, JB, deliver a specific volume.....
I located a primer for you on Positive Displacement pumps:
http://www.engineeringtoolbox.com/34_414.html
Here's a quote from within the above reference:
"Positive Displacement Pumps are constant flow machines".
In the world of positive displacement pumps, JB, boosting is not a term that applies; rather, it is appropriate for pressure boosting applications, which a metering pump application is not.
RE: Tying in a chlorine residual analyzer to a VFD metering pump
I asked the question of you, because I was hoping to gain some insight into how such a task is accomplished. I was not aware that there are such things as ELECTRONIC STROKE CONTROL.... which, your last post motivated me to crank up the search engine.
I found the following :
http://www.neptune1.com/pumps/e-stroke.htm
to be an epiphany... and a welcome addition to my applcation library.
Perhpas you'd care to share some insight into how the application was accomplished ....and is it a closed loop or open loop system.
Thanks
jO
RE: Tying in a chlorine residual analyzer to a VFD metering pump
RE: Tying in a chlorine residual analyzer to a VFD metering pump
JB:
You almost got it right;
"Obviously, the control implies reduction of the flow as well as boosting."
Not really, JB.
Here are a couple of definitions for you:
1. from Webster's New World Dictionary ...
Booster..... an auxiliary device for increasing force, power, pressure, or effectiveness.
///Unfortunately, I do not see a word "booster" in my posting. All what is see is "boosting" meaning "increasing" or "raising". See Webster New World Thesaurus.\\\
2. from Vicker's Hydraulic Handbook...
At a given speed, Positive Displacement pumps deliver constant volume {flow} independent of discharge pressure.
NO BOOSTING, JB.
Metering Pumps, JB, deliver a specific volume.....
///Please, see my quote from the referenced Mechanical Handbook. Take it up with the referenced Mechanical Handbook Editor.\\\
I located a primer for you on Positive Displacement pumps:
http://www.engineeringtoolbox.com/34_414...
///Thank you. Good to know.\\\
Here's a quote from within the above reference:
"Positive Displacement Pumps are constant flow machines".
///I did not post anything to the contrary.\\\
In the world of positive displacement pumps, JB, boosting is not a term that applies; rather, it is appropriate for pressure boosting applications, which a metering pump application is not.
///I cited the controls that implies increases and decreases within controls margins.\\\