Bi-directional pump or valve configuration? 1

[G2daG]

I'm struggling with what seems to be a simple problem: I need to be able to pump water in or out of a 200 gallon tank at 3-5 gpm, 5 - 20 psi.

What is the most economical approach? Are there bi-directional pumps that will do this? Or should I be looking at flow - reversal valves? I'd like to steer clear of any option that is prone to operator error (multiple valves, switches, etc.)

Thanks in advance!

 

[1gibson]

Most economical? Make a stand for the tank, use elevation. Pump in, drain out.

 

[MatthewL]

G2daG,

Since it sounds like you don't want to use two pumps, try two actuated three way valves that operate together (either through programming or local hand switch). The valve before the pump controls feed source (from tank or other source) and the valve after the pump controls destination (to outside or back to tank). You will probably still want isolation valves around the pump for maintenance. Hope this helps.

Regards,

Matt

Quality, quantity, cost. Pick two.

 

[bimr]

Your solution has to do with the piping arrangement, not a pump.

If you desire to make it fool proof. Your best option is to use dedicated pumps for in/out. Then label the pumps.

Another pump at the specified pump size will probably be less than the cost of cleaning up an operator mistake.

 

[G2daG]

Thanks for the responses - it sounds like my magical two way pump might not exist, at least not cheap. Two pumps may be the way to go - the simplest plumbing arrangements I can come up with cost more than adding a second pump.

Any more advice is much appreciated though!

 

[TenPenny]

I would investigate a peristaltic pump with a reversible motor, but it might well be more trouble than it's worth.

 

[RodeteG]

Will a flexible impeller pump installed on top of tank make sense?
Those are self-priming and reversible.
I am not familiar with them but I think they tend to be cheap (how much I don't know)

 

[G2daG]

RodeteG - good idea. After some research, flexible impeller pumps do look like the best option if I really want reversible flow. Some other types of positive displacement pumps such as gear, lobed or screw would also be reversible although not as viable as flexible impeller. The problem is the media is actually DI water, and flexible impeller pumps get expensive (~$2K) if I want it to be compatible.

In the end I decided to go with a simple (cheap) diaphragm pump, with a 4 way "double L" ported valve to switch the flow. These type of valves are not too common but I found them from Connant Controls, Inline Industries, and Autoclave Engineers (a division of Snap-tite, which is now also a division of Parker). This allows me to switch the pump flow by turning one valve.

 

[RodeteG]

Very nice and probaly cheap solution.

I didn’t know or ever come across those 4-way double L valves, so thanks for the input too.

 

[Drazen]

as bimr said it's all about piping arrangement.

it is even not necessary to have 3-way valves, you can do it with 2-way valves if sanitary requirements do not prohibit "dead flow" lines.

any kind of bidirectional, flexible impeller or some other special pumps are used for specific project requirements, never just for direction change, so you will unnecessary burn lot of money if you don't use simplest arrangement that will still do the job.