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Are there problems with operating near the "minimum required flow for safe pump operation"? I assume that below this level you start getting into the dead-head regime. Is there also lesser risk with operating near the minimum, but above? We are debating whether or not to add a small size pump...

If it makes any difference, we are dealing with "hot water".... between 140 and 180°F. Also, the pressure should be fairly constant, but the flow might range from 0 to 120 gallons per minute.

We want to measure water flow through a 2" pipe. The volumetric flow will be used as feedback for the multi-pump control scheme. It's a high pressure system (~600 psi) and the water is probably moving around 10 m/s. I was recommended to use Fuji Ultrasonic flow meters. Does this sound like...

@ccfowler: Not at all continuous. Frequent on-off and major variation in flow rate. The only repeating cycle is a weekly one: consistent high-volume demand on the weekends and random intermittent demand throughout the week. It's for a sanitation cleaning system in a food plant.

We'd prefer no storage tank, but I haven't heard of large enough heating systems that are feasible for our site. We need to heat the water from ~50 up to 160°F and often have flowrates as high as 120 gpm. This is around 7.8 million BTU/hr.

One of my projects is replacing a high pressure water system used to supply sanitation hoses. It consists of high pressure pumps (which put out water at ~600 psi), a water heater, and a control system to maintain the temperature and pressure. I've talked to "experts" who have argued both...

I'm working on a project where we are replacing a pumping system. The walls of the room are made of painted concrete masonry unit. The paint has not protected well against water, however, and water leaks through to the other side of the wall. It has been like this for years. Luckily my...

I realized our current pumps may meet our needs. I thought we could use a VFD to scale down flow but the lower flow curves do not have sufficient pressure (we are shooting for 600 psi/ 1380 head-ft). Our pumps are RotoJet RGB III 2x2. Rated at 60 gpm and 2370 head-ft. I don't yet know the...

I haven't yet gotten cost quotes, but what does everyone think about rebuilding a pump instead of purchasing a new one? Can we expect like new performance and reliability out of it? We'd be going to a professional pump rebuilder. I don't know what the condition of our current pumps is, just...

I've tried calling the city about this but I wasn't successful. I'll try again today and update.

Okay, thanks. In our system, the hoses have no net vertical head. The difference between each is frictional loss in horizontal pipes, and this is still much smaller than the pressure drop of the nozzle. I measured volumetric flowrates and the flowrate of the furthest hose from the pump was 11%...

"1. the pump is rated to delivering 60 gpm at a pressure of 3000 ft head" Yes. That is the information engraved on the pump panel. My understanding is that the pressure right at the pump outlet is 3000 ft-hd and that the flow is 60 GPM. I understand how to calculate losses from friction and...

We have a pump with spec'd at 60 gpm and 3000 hd-ft. I measured the flowrate out of the high pressure nozzles on the hoses and found it to range between 6.5 and 7 gpm. I assume the difference is due to frictional losses based on location. How do I calculate the change in flowrate if I were...

I'm also interested in this. Waiting for an answer.

Nothing is wrong with replacing the pumps with RotoJets. I just want to at least consider alternatives. And yes, I'm curious if ~20 year old pumps can be competitive with today's pumps in all areas. Has pumping technology progressed significantly in that time?

Is the 3960 a unit conversion factor? We have RotoJet centrifugal pumps.

I'm replacing an old high pressure water pumping system. The current system uses two identical pumps (one main and one backup). The current pump specs: Capacity (GPM): 60 Head (ft): 2370 Speed (RPM): 4380 Power: 40 HP P.F.: 36% Load eff: 92% ================================== Is that...