Parallel pump system operations can get very weird very easily. Identical pumps with identical motors connected by functionally identical piping configurations are the non-existent ideal. The messy end of the spectrum involves dissimilar pumps connected at different points within a complex...
EdStainless and Artisi are absolutely correct that over-sizing pumps results in efficiency and maintenance burdens (stars to both!). I fully agree and have made similar statements many times.
In my view, the apparently simple 10% margin requirement is not bad on its own because that is a...
It wouldn't hurt to verify the actual condition and composition of the lube oil. Contamination, non-conforming make-up additions, etc. may result in property changes just enough to cause or magnify troubles while the oil appears to be in good condition.
Valuable advice from a professor many...
Seems to me that you are looking to take on lots of needlessly troublesome and costly problems in order to chase a trivial improvement in efficiency. It is not likely to provide a favorable cost vs. benefit situation. The efficiency losses associated with the increased operating problems will...
EdStainless's recommendations are assuredly an excellent starting point to sorting out your problem. I've dealt with similar problems, and isolating and testing the true performance of each compressor was the most valuable step. Pay careful attention to every aspect of the problem. You may...
davidbeach, you are absolutely correct! What energy goes into a battery is always substantially more than the energy that comes out!
Whenever subsidies are required on a continuing basis for something, it inherently cannot be truly viable. Currently, EV's are the beneficiaries of significant...
Plug-in electric vehicles introduce very substantial parasitic losses that almost everyone conveniently omits from discussions of their sublime wondrousness. These include step up losses at the power generation site, transmission losses, step down losses, distribution losses, step down losses to...
Wood chippers involve relatively significant rotational inertia in addition to shock loads. I would want to include a torque converter at the engine flywheel to temper the effects of acceleration to running speed and instantaneous torque variations from both the engine and the wood chipper...
DwaliX,
Your question provides little useful information to aid other in providing a more useful answer. If your concern is based on an operating temperature problem, be sure to get very good, well-informed advice. It is not unusual to find that switching to a more viscous oil because of high...
My view of this question may be somewhat different while sharing much with LittleInch.
If this were a very high energy pump, such as a multi-thousand horsepower boiler feed pump, that would suffer from a very rapid and damaging temperature rise during a shut-off condition, nobody in their...
Perhaps I should clarify my perspective and concerns. Getting a system working seemingly nicely during startup makes everything nice for the designers and installers, and it may make operations happy for a while. It gets the construction and startup bills paid. Later, there is no small risk that...
ATPD,
You said the magic words indicating that you have ductwork between the atmospheric air supply and the Venturi flow meter. Thus, you have an unknown restriction between the atmospheric pressure and the true upstream pressure needed for accurate and repeatable meter performance. The inlet...
From what I have read so far, it seems to make the most sense to use multiple small pumps since you need to distribute water along the way from the river to the top. It makes no sense to pump water all the way to the top to simply let most of it flow back down the hill by gravity. Using...
Back in the 1970's, some of the major US pump manufacturers published information on select models of their pumps being applied to just such a duty. I recall reading some of this literature at the time, and all aspects of using these pumps as turbines were addressed very thoroughly. The...
Without providing much more definitive information, you cannot expect any meaningful answer.
Valuable advice from a professor many years ago: First, design for graceful failure. Everything we build will eventually fail, so we must strive to avoid injuries or secondary damage when that failure...
I would check carefully to verify the suitability of the lubricants in use. It is not unusual for excessive oil viscosity to be a significant factor in excessive temperature problems.
Valuable advice from a professor many years ago: First, design for graceful failure. Everything we build...
As indicated by others, much more information is needed for best advice to be possible. With the multiple connections in the piping system and the multiple pumps with differing driver characteristics, this system seems to be an invitation to control and pump operation problems. Based on my...
Having had some experience with pumps operating in parallel working in similarly poor regions of their curves, I suggest that you not be surprised by maintenance problems being much worse than expected. Your best hope may well be for them to hold up long enough to get from one scheduled...
Unless very substantial variations from equal flow rates at the four discharges can be tolerated, I would include some suitable means of flow measurement and flow control into each of the four discharge lines to keep the individual flow rates within tolerable ranges for their specific needs. A...
Forget about the VFD. They can be excellent devices in the right circumstances, but most commonly, their use is an indication that someone doesn't really understand what they are doing or why. This is NOT a suitable application for a VFD! All it will do in this application is increase both...
