Pump restrictions???

[Peppie]

I need to understand why one type of pump can be restricted and another one cant?

Does a high pressure pump allow you to restrict it? Does the free flow pump with low head pressure not allow you to restrict it?

What is the difference in the pump that allows the restriction?
I have been informed the Dolphin Amp master, and the Reeflo are good pumps for this restriction. What makes them able to restrict their flow?

 

[eww]

Great question. Once just gone by what people have said and what I've read on Reeflo's sure for their Dart pump. I'm curious about the whys as well. Tagging along

Sent from my DROIDX using Tapatalk

 

[Peppie]

Sometimes I cant swallow " Because I said so" I am by no means saying people dont know what they are talking about. They are speaking from personal experience. I value their knowledge based on their exp. Sometimes I just need more facts.

 

[IPisces]

I always assumed it had something to do with the quality of the pump and its ability to keep from running hot and burnig up from being stressed from the reduction in flow. I could see it putting some stress on the motor if the impeller is not spinning freely.

 

[Scooterman]

I always assumed it had something to do with the quality of the pump and its ability to keep from running hot and burnig up from being stressed from the reduction in flow. I could see it putting some stress on the motor if the impeller is not spinning freely.

I'd say your assumptions are correct. If you noticed how the Ree flow Dart/Snapper have huge Inlets and outlets, these pumps are made for high FLOW but at the cost of lower pressure. The Pressure rated pumps are much smaller outlets and inlets and can pump water under pressure as high as 35ft straight up. it is all in the design in the pump, not necessary quality as much as how the MOTOR is designed. You have to remember every pump has a MOTOR part and a impeller & housing part which is the actual pump part, it is two components that make a pump. The motor is wired for different designs such as pressure vrs. low power consumption. The windings are different, you can have several designs that use more windings or maybe higher gauge wire used for the windings or a combination of both, even windings driven at higher voltages such as 220/440 volts AC. Now all that said we can talk about pump design, the pumps with large inlets and large outlets allow water to free flow in under little pressure, the impeller design just pushes the water on with little effort making this a low power high flow combination type pump. The pump housing and impeller design can be adjusted and tweaked to get different characteristics out of the pump, just like a prop on a plane that has pitch etc. The same holds true for high pressure pumps just you take in water with as large of an inlet as you can get and push it under higher pressures forcing it out of a smaller outlet, design of the Motor and the pump allows for a large numbers of flow design based on these basics. There is always more to it than that but that is the practical part of pump designs. Now I've used a Maxi Jet 1200 to pump water over 7 feet to my water tank when I needed to fill it, using a 1/2" hose and it worked, same can happen to any pump. The thing is there is always allowable ranges you can play with and adjust, even high flow, low power pumps, they can be restricted to some point. You can actually take a pressure rated pump, restrict it and cause it to use less power which seems like the opposite of what you would think being you're seemingly making it work harder but you can restrict the outlet and actually consume less power because of fluid dynamics which is above me but the math adds up to less water flow less power, keeping it simple. My thought is on your pump inlet make them as big as you can get them, I usually go a size larger than the threaded inlet. On the outlet depending on your head requirements you can go the threaded size or even larger to reduce some pf the pressure, if you don't need it all, sizing the piping and reducing restrictions is preferable to the restriction by means a ball or gate valve but you can use them just don't put the ball/gate too close to the pump, the farther down the line the better.
Hope this helps, I don't claim to be an expert here but have some of the basic knowledge that I can share!

 

[BigAl07]

Very well written Scooterman. You hit the nail on the head. It's like with any other "motor" they are designed to work under a certain load and outside of that design parameter they may become very inefficient or even fail. The actual design of the pump (impeller and housing) play a HUGE part in allowable pressure. In many "High Flow Low Pressure" pumps if you apply more pressure than it can push you get "Cavitation" which is the impeller slipping instead of getting a good bite and pushing water. When this happens the motor can either over-rotate or it can create so much heat it over-heats. I once had a slight tank melt-down because a mess net went into a pump unit and passed all the way through the unit (large inlet and smaller outlet) but the "Tie string" got snapped in the inside of the outlet resulting in the mesh bag partially blocking the exiting flow. This caused a huge reduction in flow and the motor of the pump was "spinning it's wheels" and not moving much water. This allowed the water in and around the pump to heat up and over time ( I have no idea how long because I was out of town for the night) and took my 90g tank temps (w/28g sump and 18g fuge) from 78 to 86. I only lost a couple of coral but I found out first hand not all pumps can tolerate high pressure loads and still function correctly.

What's amazing is that a lot of people don't understand how "Heavy" water is when it goes straight up. I remember back many years ago an episode of "Mr. Wizards World" where he ran a very small diameter tube up an outside wall of an apartment building. He then connected a very high pressure compressor to the tubing and added a colored liquid (Kool-Aid maybe?) and turned on the pump. It very easily pushed the liquid up 5', 10' then it started to visibly get slower and slower. I don't remember where it finally stopped but it wasn't very high at all and the pressure on the compressor was reading a silly high #. This is why some pumps tolerate little to no "pressure" because even if we run the plumbing just right we're adding "head pressure" with every foot we push up.

Ok enough rambling for me for right now LOL!

 

[IPisces]

Those are great explanations Scooterman and BigAl07. I guess I should have said design of the pump, not quality. Anyway, that expained a lot for me.

 

[Scooterman]

Those are great expanations Scooterman and BigAl07. I guess I should have said design of the pump, not quality. Anyway, that expained a lot for me.

Quality comes in hand with a good design. One thing to also consider or think about is the submersibles, they are slightly different than a regular pump but ultimately they do pump water.

 

[Peppie]

Thanks Scoot and Big Al,
I am sure I was not the only one who was wondering.
This has helped.

 

[mojoreef]

The pump you were looking at can be knocked down from 5600 to 3000 gph and the kit is about 30 bucks,


Mojo

 

[Peppie]

The pump you were looking at can be knocked down from 5600 to 3000 gph and the kit is about 30 bucks,


Mojo

Thanks Mike, Still alittle more pump than I need for a return pump. But it will work for a closed loop.