It should be "Loss motion mechanism". It is a type of plunger return action design by a spring instead of the cam pulling it on the suction stroke. Typically used for low cost design application.
This may be out of topic. Another commonly confused terminology is the specific speed Ns. Commonly referred to as pump specific speed which is only correct for a single stage pump.
The actual reference should be to the impeller design or geometry.
Suction pressure also decide type of pump to use. End suction or over hung pump has lower suction pressure capability than between bearing pump. A high suction pressure system can have low NPSHa due to the high vapour pressure of the liquid.
Your client need some education on pump operation. To add 30% to the rated flow for such a big pump is a waste of 30% extra energy
necessary to do the job. It means 642 gpm of water is being dump back to the suction. You can check it easily with the require motor power at 2140 gpm and 2782 gpm...
Most of the postings have concentrating on the pump curve shape. For parallel operation need to look at the system curve also. If the system curve is steep ( mostly friction), the % head rise is not so critical.
If the system curve is relatively flat, (short piping , low friction and high...
Victor, You did not mention how is the setup.
Is it a pipe line installation where the head is mainly friction or a high pressure inject. If it is a long pipe line installation, where the head is mainly friction, 2 stations installation will required lower pressure piping and cost of the pipe...
Thunderspeed, you already provided the answer your self in your 24-Aug post.
It is easy to identify the the suction and discharge for an end suction pump. But not that simple for
vertical inline pump, Multistage, axial split case, VS6 type. Here the OP mentioned about a complete mounted system.
For Plan 53s, because the barrier fluid is pressurised, it does not get contaminated by the pumped liquid. You refill it when the pressure is almost reaching the the seal chamber pressure.
For Plan 52,the pump liquid gets into the reservoir and mixed with the buffer fluid. If the pumped liquid...
The HTF pump may able to benefit from VFD because it is mostly friction head.
But for the BFP, as BigInch explained, it is mostly static head (pressure),It is a relatively flat system curve.
You need to maintain the pump discharge pressure at 110 Bar + piping friction loss at what ever flow...
One is using 5 HP and the other is using 10HP yet is cheaper.
If both are rated for the same flow and head. The 10HP pump is definitely very much lower in efficiency and build quality.
I had came across pump specification prepared by a world re-known engineering company asking for VFD for a centrifugal pump rated for 25 meter head with a 5.5kW motor [ponder]
Thanks for all your valuable input. I personally prefer the traditional solid foundation. But for this case, because of the short suction piping space,there are limitation to design a more flexible piping.
Because the pump is center line mounted,the vendor can just use one of their standard API...
