Turing a non priming pump into a self priming/automatic priming pump
Turing a non priming pump into a self priming/automatic priming pump
(OP)
Hello,
I have never posted on this site before but find many answers to many questions i have on here.
No I have one to ask directly.
I have the need to install a pump for pond pumping and sump pumping. Im using 2" Motorized valves to select the source... not really part of my question i just wanted to give some background.
For a while I've been looking at 2HP Self Priming pumps.... Having that self priming is a very important thing however the pay off is a dramatic loss in pump efficiency. Best i can hope for with a Self Primer is 50% however with a regular centrifugal pump is 85%. So my idea is this. I want to use a bypass valve,
This valve
http://www.omega.com/Green/pdf/SV3500.pdf
to turn this pump:
http://www.wegotpumps.com/pdfs/87-88.pdf
into a self priming pump
Take a look at my drawing to see what I am thinking.
http://www.greenteksolutions.us/pumpidea.png
I need to know if this has any chance of working. the basic theory of this is that once the pump is primed i will see a dramatic rise in outlet pressure (measured by a pressure sensor) and the system will shut off the valve returning the pump to its high efficiency mode of operation.
Thank you for any help you have to offer.
I have never posted on this site before but find many answers to many questions i have on here.
No I have one to ask directly.
I have the need to install a pump for pond pumping and sump pumping. Im using 2" Motorized valves to select the source... not really part of my question i just wanted to give some background.
For a while I've been looking at 2HP Self Priming pumps.... Having that self priming is a very important thing however the pay off is a dramatic loss in pump efficiency. Best i can hope for with a Self Primer is 50% however with a regular centrifugal pump is 85%. So my idea is this. I want to use a bypass valve,
This valve
http://www.omega.com/Green/pdf/SV3500.pdf
to turn this pump:
http://www.wegotpumps.com/pdfs/87-88.pdf
into a self priming pump
Take a look at my drawing to see what I am thinking.
http://www.greenteksolutions.us/pumpidea.png
I need to know if this has any chance of working. the basic theory of this is that once the pump is primed i will see a dramatic rise in outlet pressure (measured by a pressure sensor) and the system will shut off the valve returning the pump to its high efficiency mode of operation.
Thank you for any help you have to offer.





RE: Turing a non priming pump into a self priming/automatic priming pump
RE: Turing a non priming pump into a self priming/automatic priming pump
I used a formula I found and have kept around for some time
Power out/Power in = Pump Eff%
The formula works as this: ( I left out SG of water and just used 1 as it only varies slightly )
(Head (ft) X Flow (GPM X 8.33)/33000 = HP Out
Picking a point that I will use regularly on the flow curve can get me Head & Flow.
(60' x 70 GPM x 8.33)/33000 = 1.06 HP
1.06/2 = 53%
Still much better then the 35% of the self priming
In this application the contractor is all about gaining every efficiency point possible . Normally I wouldn't care but....
RE: Turing a non priming pump into a self priming/automatic priming pump
RE: Turing a non priming pump into a self priming/automatic priming pump
What is the term GPM x 8.33?
RE: Turing a non priming pump into a self priming/automatic priming pump
the 8.33 is the weight of one gallon of water, roughly. the GPM is just the units of the number that precedes it. 70 GPM or gallons per min
anyways the math really doesn't matter as part of my initial question. Im looking to know if this system will work. no matter what the math is, the non-selfpriming pump is more efficient then the self priming pump
RE: Turing a non priming pump into a self priming/automatic priming pump
Flow IGPM x H ft x SG / 3300/ pump efficiency (decimal)
if USGPM subsitute 3300 with 3960.
Yes it should work - you could replace the inverted U pipework on the inlet with a small holding tank.
RE: Turing a non priming pump into a self priming/automatic priming pump
The 3960 just combines the weight of water (8.33) and the 33000 into on. if you use the number the answer is the same.
Here is my source
http://www.mcnallyinstitute.com/06-html/6-01.html
Thank you. you seam to be very knowable about pumping, would you mind looking at my other post about NPSHR and NPSHA?
RE: Turing a non priming pump into a self priming/automatic priming pump
Mike Halloran
Pembroke Pines, FL, USA
RE: Turing a non priming pump into a self priming/automatic priming pump
The pump has a 1-1/2 suction and a 1-1/4 outlet.
So maybe 2" on the inlet and 1-1/2" outlet?
How much higher should the top of the p trap be? I was thinking 18" over the pump base? And also the same for the discharge just to help keep more water in the pump for the next cycle. I'm also think I will put way over sized section on the discharge right at the pump for 8" or so to make sure the water and air have time to seperate. I'm thinking a 3" section for this.
Thoughts?
RE: Turing a non priming pump into a self priming/automatic priming pump
RE: Turing a non priming pump into a self priming/automatic priming pump
RE: Turing a non priming pump into a self priming/automatic priming pump
A small leak in the system, especially in suction side, will give big problem, no matter you use, self priming, or modified priming system, vacuum assist priming or just standard foot valve.
Find good quality foot valve :)
RE: Turing a non priming pump into a self priming/automatic priming pump
RE: Turing a non priming pump into a self priming/automatic priming pump
that and after the system in winterized or there is maintenance performed on the system i don't want to leave it up to the grounds crew to prime the pump... with this system i can assure that i will alway be able to prime the pump automatically.
Another note. Im plumbing city water fill into the suction side of the pump piping so i can turn on the city water to fill the system if the water in the pump is lost for one reason or another.
RE: Turing a non priming pump into a self priming/automatic priming pump
If your inverted U has been drained at anytime, the system will not re-prime automatically, the inverted U will need filling and any air in the pump case purged.
RE: Turing a non priming pump into a self priming/automatic priming pump
I have city water plumbed into that suction side of the plumbing. On a valve by the way. The grounds crew will have a 3 way switch, on, off and maintenance/winterize. If at any time the system is turned off it will trigger a start up subroutine in the controller. When the system is turned on again it will fill the pump and all other pipes with water from the city for a given time before enabling the pump to run again. Thus automatically priming the system with no human interaction. I will know when the system is filled as I have a flow meter on the outlet pipe to calcite flow as well as pressure reading from a pressure transducer.
Automatic is a term I used if I can wirte a program to process.
RE: Turing a non priming pump into a self priming/automatic priming pump
RE: Turing a non priming pump into a self priming/automatic priming pump
The controller will be much simple, just run the vacuum pump for a while (depends on the suction pipe volume and vacuum pump capacity) before run the main pump.
Install a level switch that will activate the solenoid valve on certain level to prevent water ingress. Water trap will be advantage. Once the solenoid valve is activated, the level switch should also cut the power of vacuum pump.
This system will need 5-10 second for primed; while the self priming pumps may require more than 1 minutes before primed.
RE: Turing a non priming pump into a self priming/automatic priming pump
As for being complex control really it's simple, any complex operational stuff will just be a few lines of code. That part is easy.
In the end if i'm not sure the auto self priming pump operation will not work I plan on just going back to the other inefficient pump.
RE: Turing a non priming pump into a self priming/automatic priming pump