Rain Water Butt Pump

[Mickey]

I'm looking to pump rain water from a ground level water Butt to a small loft water storage tank where it can be used to flush toilets   One of the solutions recommend, on an earlier post, is the Navitron  Solar Powered Well pump kit.    I've looked on the Navitron website and can't find any tech details. 

Could Ivan or one of the Nav staff advise?    I'm particularly interested in:

Max Hydraulic head?
Well dry protection?
Auto shut off when the loft tank is full?

Thanks

Mickey

[wyleu]

The CAT book; http://www.cat.org.uk/catpubs/book.tmpl?sku=wb is a good reference for this sort of project

[Mickey]

Thanks - looks interesting - but before I decide to buy the book I would like more tech info from Nav on the well pump solution
Rgds Mickey

[wyleu]

The book details the filtering which is an easy part to forget in such a scheme.

[stephen]

Look through the boat industry there are many 12v pumps for about £40 which will pump a tremendous head of water and will start unprimed. Not much filtering is required just a strainer.
also have a look at it aint easy being green. Dick did somthing similar from his stream.

If you cant find anything let me know i have some info somewhere.

Regards

Stephen

[AndySV1K]

Ive been looking for an alternative pump to the one im using.  Mine pumps water from the storage tank straight into the cistern of the first floor toilet.  It works, but theres just not enough pressure there so filling takes quite a bit longer than on mains.

Now i cant quote technical physics terminology, but my lamens terms are....

ignore what it says on the box about the head height the pump can reach.

My pump has to raise the water around 2-3m, it has a 6m head capability, yet the flow would cease well before reaching that height and i beleive the reason is, because they quote an underwater head height.  this is obviously very different to a head height above the water line.

I have found a pump that looks suitable, it can pump up to 60m and can generate 6bar, however the two things that put me off trying it are

a) the price.  Around £150 for the pump plus £50 for the pressure switch kit
b) the noise.  Its a diaphragm pump and i gather these are more noisy than conventional rotary pumps.

Andy.

[stephen]

Please forgive me if i am not quite right as it was some time since i studied fluid mechanics.
If you are referring to maximum head then the amount of water that should come out of the end of the pipe at that head is nothing, zilch. This is because the pump uses all the  pressure / energy to the pump the water to this height but no more to let it run out.
The head is also measured from the top of a pond/ lake to the pipe outlet. So if the pump is 2mtrs below the water it is not counted in the head height.
Don’t forget that frictional losses in the pipe will also contribute to head losses. Any pipe below 25mm with a few bends will give greater resistance. Try to use ribbed piping as well as when you bend ribbed piping it does not restrict the flow like a hose pipe does. Try Screwfix or Machine Mart for the pipe.
The pumps I have seen in use are flojet pumps used on boats. They detect pressure drop and flow, then turn the pump on. As they are bilge pumps they don’t mind a bit of dirt so a course filter is all you need.
Hope that helps
Regards
Stephen.

[wyleu]

Peristaltic Pumps might be the answer.

http://www.williamsonpumps.co.uk/

[Mickey]

Hi All,

Thanks for al the very useful advice.  I've sent an email request to Williams Pumps outlining the requirement and asking for a priced solution.  Let's see what transpires?   I'll keep you all informed.

Mickey

[Ivan]

The Navitron solar powered pumps are designed for high head, low flow rate, and supplied with solar panels to drive them.

I believe the flow rate is:

80litres/hour at 10m head, or it can be used with higher heads up to about 20m, although flow rate is reduced.

[Amaterasu]

which means it will take about 5 mins to refill the cistern.

I'll leave you to make your own mind up if this is quick enough!

[Ivan]

Being solar powered, it would also depend on the amount of sunshine available!

The idea is that it would fill a large tank in the attic (cold water storage tank), and this would be used to fill cisterns etc as and when required. It is also used as a well pump for the same purpose.

[AndySV1K]

or about 12 hours if you flush after around 7pm!

Andy.

[Mickey]

Thanks All.

The system is taking shape and would consist of:-

An attic Rain Water  (RW) storage tank - filled by a pump (possibly solar powered) from the ground located RW collecting butt(s).   The attics tank would gravity feed the cisterns as Ivan suggests

I'm still unclear as to how to control the pump switch on/off?   I've been told that a pressure switch and ball valve is not ideal as the system tends to "shudder" as the pump switches off and the ball valve partly opens again as the pressure equalizes - this in turn starts the pump again etc etc.   Also  I would need  collecting tank dry protection?

Rgds   Mickey

[AndySV1K]

Also, a ball cock valve has a very restricted flow, ok if you are using mains pressure, not so good if you are using electricity to pump the water.  Ideally you want as few restrictons to the water flow as possible.

Using a float switch and relay, its quite straight forward to operate the pump.  Mine works extremely well and the float switch doesnt bounce at all so once the fill level is reached the pump is switched off and it stays off.

Im currently looking into modifying torbeck valves to do the same job.  If and when i get the design sorted, i can make you one if you like.

Andy.