Pump - rigid plumbing

Russ Johnson said:
You'd need a helluva supply to do that.
Click to expand...

Russ thanks for your response.

The other day I used my 13hp gearbox driven TS1511 combination, to wash and I had it feed from a tank via 1" line and after connected it to the household supply via 75' of 3/4" hose .

I could feel the difference on the gun with the pressure feed. After looking up the specs of both the TS 1511 and TSF2021 I see they both have the same inlet specs of max pressure feed 125 psi and max vacuum of 7.9" Hg.

I was wondering what is gained by feeding the pump?

The answer should be volume.

The same way that centrifugal pumps have performance curves at a particular rpm, the triplex plunger pumps performance curve may reveal that with a smaller pump inlet vacuum the triplex pumps may output more water.


Russ J. do you have performance curves for any of the general pumps?
 
Nigel, you're comparing a centrifugal pump to a positive displacement pump...two completely different critters.

As long as the inlet vacuum is less than 7.9 and the pump is in good mechanical shape, the flow should not differ from flooded or pressure fed.
 
Russ Johnson said:
Nigel, you're comparing a centrifugal pump to a positive displacement pump...two completely different critters.

As long as the inlet vacuum is less than 7.9 and the pump is in good mechanical shape, the flow should not differ from flooded or pressure fed.
Click to expand...


I got the shovel out and started digging Russ, I really felt that I had more flow when I pressure feed my TS 1511 , maybe I was not imagining.

look at this off general pump website.

Volumetric Efficiency compares the pumps actual output to its theoretical output. If there were no losses in the pumping system, its flow would equal:
Area x Stroke x Number of Cylinders x Crankshaft Speed
231 in3 /gallon = gpm

Dividing the actual flow by the theoretical value calculated above will yield a value which, taken as a percent, indicates volumetric efficiency.

Valve timing is a major factor in achieving good volumetric efficiency. This timing is affected by the relationship among poppet weight, spring rate, poppet travel distance, plunger speed, and plunger diameter.

Inlet Flow Curve relates volumetric efficiency to specific inlet pressures. General Pump provides inlet flow curve charts for all its pumps, on request.
Click to expand...
LINK

From what I understand they are saying, the pumps volumetric efficiency varies with pump inlet supply.

I requested the inlet flow charts for the most common pumps via email.

Found some other interesting stuff too, will add to other related threads.
 
Use an ag hose on the suction side of the pump and always remember to flood the pump and never starve it. Do not use QC's on the suction side of the pump. Jerry is right. Brass is easy to find and cheap. DO NOT USE TEFLON TAPE. Get out of the habit of using teflon tape on the low pressure side of the pump and discharge side of the pump. Use medium threadlocker. We have seen many cracked fittings with teflon tape hanging out due to overtightening. We have seen the inlets of guns, Mosmatic gun swivels and couplers cracked due to overtightening.
 
My Father, Rex, does not use Garden Hose fittings on the suction side of the pump. He said that they leak and pull air sometimes.
 
I'm throwing a flag on this one.. Lock-Tite

PWProducts said:
Use an ag hose on the suction side of the pump and always remember to flood the pump and never starve it. Do not use QC's on the suction side of the pump. Jerry is right. Brass is easy to find and cheap. DO NOT USE TEFLON TAPE. Get out of the habit of using teflon tape on the low pressure side of the pump and discharge side of the pump. Use medium threadlocker. We have seen many cracked fittings with teflon tape hanging out due to overtightening. We have seen the inlets of guns, Mosmatic gun swivels and couplers cracked due to overtightening.
Click to expand...

I appreciate everyone's effort that is productive,
but I'm throwing a technical flag on this one..
overtightening, is an "abuse of the fitting, granted, BUT..
NO field-service tech worth his salt would EVER agree with
welding these parts together with soft, medium or hard goo
or lock-tite of ANY type, at ANY time replacing the
"wonderfully-Serviceable" teflon tape.

Lock-tite is a PROBLEM to serviceability,
and I have harassed MTM hydro, Suttner, MV and PA,
at every opportunity (trade-shows,)
to STOP gluing fittings and connectors together..
It is not an "opinion", it is a fact that..
when you begin to loosen a glued fitting, the "glass shatters"
into thousands of tiny "teeth" that then grind the brass threads
out of shape, as you complete disassembling the connection.
The first time you are in a hurry to remove a part,
and the parts start to turn, but suddenly they get tighter as you turn,
you'll know exactly what I'm "all emotional" about.
If a pump mfr uses glue on their valve caps,
..If they aren't confident the o-ring will hold,
I won't sell their pumps.

nuf said.
 
Last edited:
Well, I love teflon tape, and I think threadlocker is wonderful stuff.
 
Sorry, this post belongs here, I put in the wrong thread prior (Rated Horsepower)

I am still waiting on General Pump to respond to the statement on their website, I did however get an email for the customer service manager Mr Cook, but it did not contain the information.

Today I asked the question to AR North America, Mr Al Stasny
Technical Manager.

I must say he was very helpful and we discussed much more than volumetric efficiency. He however did not have any graphs but did confirm that volumetric efficiency is affected by inlet line design and pressure.

Typically you can have a 5% to 8% increase in volumetric efficiency from a small negative (sucking/pulling) to zero (flooded) inlet, compared to a 30 to 40 psi pressurized inlet (he also said that over pressurization of the inlet has a negative side , 30 to 40psi is tested most efficient, I have also seen this on Cat Pumps website).

If you had to pressure feed a high flow pump like a General Pump TSF2021 (1750 rpm = 8.5 gpm) AR /General Pump and Cat Pumps all recommend a pump that is at least twice the rated output at a particular speed. So my TSF2021 needs 16gpm pump to feed it (lol!!), reason being it has to do with the acceleration the plungers experience during pumping.




The question now remains, what is our flooded pumps really pumping? Hummm!! ( MR Al said that in all the years experience, I was the only one he could remember that was concerned about volumetric efficiency, wow, I have nothing better to do, lol)
 
Sirocco Jerry said:
I appreciate everyone's effort that is productive,
but I'm throwing a technical flag on this one..
overtightening, is an "abuse of the fitting, granted, BUT..
NO field-service tech worth his salt would EVER agree with
welding these parts together with soft, medium or hard goo
or lock-tite of ANY type, at ANY time replacing the
"wonderfully-Serviceable" teflon tape.

Lock-tite is a PROBLEM to serviceability,
and I have harassed MTM hydro, Suttner, MV and PA,
at every opportunity (trade-shows,)
to STOP gluing fittings and connectors together..
It is not an "opinion", it is a fact that..
when you begin to loosen a glued fitting, the "glass shatters"
into thousands of tiny "teeth" that then grind the brass threads
out of shape, as you complete disassembling the connection.
The first time you are in a hurry to remove a part,
and the parts start to turn, but suddenly they get tighter as you turn,
you'll know exactly what I'm "all emotional" about.
If a pump mfr uses glue on their valve caps,
..If they aren't confident the o-ring will hold,
I won't sell their pumps.

nuf said.
Click to expand...

Jerry, well said on the tef tape. You can tell a lot about the quality of a service dep't by crap like that. I stopped going to one local company for service when I noticed their custom machines had unloaders mounted on the pumps. If they cut corners on that, I don't want them working on my stuff.
 
offdutyfireman said:
I noticed their custom machines had unloaders mounted on the pumps. If they cut corners on that, I don't want them working on my stuff.
Click to expand...

How come you dont like unloaders mounted on the pumps?
 
Well, actually, for the beefiest of beef, the unloader mounting block ROCKS,
but when space is limited, there is another option..
we use these a lot..
a 10,000 psi-steel flare-fittling can support the weight of a medium-size unloader for years, and is really fast for serviceability..
I love "compression-swivels"
we can change an unloader in 4 minutes,
clean-hands to clean-hands including test-adjustment.
look at the images on our website of the PCG 31hp Plumbing..
see how the unloader is in a "pivoting" position against the head of the pump..
the up-and-down vibration of the system would loosen the fitting
long before the fitting would break. ..but they stay tight ! and..
We have re-used these fittings year after year on these units,
especially since we add "Anti-Sieze" compound to keep them from rusting.

It' all finesse guys ..
which tools you use, when you use what fittings.
Let quality experience guide you..
Don't waste time.
And when you find one.. respect the tech.
If you haven't found one yet,
go with the EXTRA-beef, like a good fireman..
Prevention becomes profitable
 
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