Self acting water pump - no external driver

[brianslater]

Hi guys,
does anyone remeber this type of primitve pump, invented in the victorian days. Basically it consists of a long suction pipe coming (100m typical 50mm dia) from an slightly elevated area, feeds through a type of flapper valve which closes once a certain flowrate has been established. This then forces the water up through an nrv supported by a simple hydraulic reservoir to a header tank. So the kinetic enegry of the line of water is abruptly stopped and converted into potential energy stored in the header tank. Brilliantly simple, almost no moving parts - hope you understand this

does anyone know if this device is still made anywhere in the world?

 

[saxon]

brianslater, Yep, it's called an hydraulic ram. Still made? Yep, see the following site:

http://www.theramcompany.com

Hope this helps.
saxon

 

[brianslater]

Hi Saxon
Thats the word, I couldnt remember it as I hadnt seen one for 30 years

Have visited the site. I doubt the claims of %15-20 efficiency.

I seem to remember it was around 10% (of kinetic energy converted to stored PE)

I notice the cals are very wooly, seems they prefer suck it and see engineering - not very inspiring. the importance is to have a large suction pipe (at least a 2" for a 2" valve I would say)

I cant say that pvc seems a good material to use. Its too flexible and you lose pressure generation with pipe wall expansion

The cast aluminium version seems better (at a price). It looks like it has a bladder accumulator on the end? Of course this themn becomes a pressure vessel (if operation at over 50psig - I think?). that entails insurance and annual inspections?? Not so simple

The last one I saw was solid cast iron over 50 years old

It operated alongside a stream with a weir. It pumped water into a roof storage tank 30ft up belonging to the mill house

It reputedly worked non stop with re-machining of the gun metal flapper valve every 5 years or so. It would sometimes stop in a thunderstorm

thanks again

 

[barryadamson]

One Australian manufacturer is named 'Billabong' in Melbourne I think.

The best publication I have used, is 'A Manual of the Hydraulic Ram for Pumping Water' by Simon Watt.

It is published by Intermedialte Technology Publications (ITDG)of 9 King St,London WC2E 8HN, UK.

This manual (about 40 pages) is a full design manual that guides you thru the stages for you to construct one yourself, out of steel pipe bits. It explains the full operation, design & tuning. A very good practical book that was produced for developing countries.

Regards
barryadamson

 

[brianslater]

Hi barry
will search for billabong

That manual sounds good, Ill see if I can get hold off it. I am thinking of making this a project for my students in the local tech. That will really bend their minds (well we are in central thailand)

many thanks

 

[barryadamson]

Brian
There is another way of pumping water without using a hydraulic ram or an external source of power. Use a pump to pump the water required & power the pump with another pump (turned back to front so the the second pump acts as a turbine to drive the first pump).

1 PUMP 1 - Determine the quantity (Q1) of water required at the head (H1) that you want to pump to, & select a pump to handle that duty. From the HQ curve & the efficiency at that duty point, select the power required (kW) to pump the required Q1 to the head H1.

2 PUMP 2 - Select the head (H2) that you have in the stream (from a small dam to the pump position). Assume about 50 % efficiency (that means the kW required is doubled) & then select a pump with a quantity (Q2), head (H2) & power required of double that required to pump Q1 to H1.

3 With the pumps connected back to back, & the small dam providing a quantity of Q2 into the delivery side of the pump 2 from a head of H2 (now acting as a turbine with the suction side of the pump running to waste), the small dam can now provide water into the suction side of pump 1 with the delivery of Q1 to H1.

4 Of course you will have to calculate head losses & determine pipe sizes & check whether my guess of 50 % efficiency of the combination is realistic.

Obviously it is not as simple as that - you would also have to check whether the pump was for a small head, a range of heads, short or long term operation, etc, etc. but the principle may be of use for a specific application.

Regards
Barry

 

[brianslater]

Hi Barry
Might as well go for a water wheel (overshot or undershot) driving a commercial slow speed piston PD pump
These are very cheaply available in the far east BTW (ca $40 for a 1/2hp capacity) and almost as venerable as the ram pump
and are extremely durable (typically 5 years before overhaul of the valve (a simple job replacing springs and rubber seats few $ )
Conventional impellor pumps are expensive, high speed and wear out seals quickly

Not sure about efficiency.

I propose to try out some options on a nearby river barrage

Approx 10m head and pumping up to a vegetal market garden say 20m high inc storage

Conventionally the farmers use a kubota mechanical buffalo hitching to a downhole pump to stretch into the river. When I told them they could do the same without an engine and using expensive deisel they thought I was ga ga, gone troppo
So we shall see, Ive got a case of beer bet on with them

 

[barryadamson]

Brian
I can see where you are coming from & I agree that back to back pumps would not be a viable option for you. It appears that the hydraulic ram is certainly the answer. I think your case of beer is very safe.

At one stage, there was also a hose pump tried in developing countries where a hose was wrapped around a drum & placed into a stream. The drum had paddles on the end so that the stream flow would rotate the drum. Each rotation would 'gulp' up a little water in the hose (in the direction of the wrapping) & this would be directed (thru' a rotatable hose connection from the coil to a hose on shore) up to an elevated position. I do not know of the efficiency (or usefulness) of this device. I have not seen any hydraulic results. It may be an interesting (& practical) project for students.

By the way, the article I suggested to you on the hydraulic ram will be VERY useful to you because it is based on first principles (meaning a person who has never constructed a ram, will have ALL of the information in one manual). It was written by Simon Watt (years ago) who also wrote manuals on 'well construction' & 'ferro cement storage tanks.' These manuals would have to be the best I have seen for a first time user. The storage tanks (I think) were about 4 cub metres.

If you have problems of obtaining the hydraulic ram manual, email me on badamson@austarmetro.com.au & I may be able to provide you some info.

I am aware that the largest problem in developing countries is WHERE DO I FIND THE INFO.

Regards
Barry

 

[brianslater]

Hi Barry
Thanks for the tip about the oild drum hose thing. we dont have any fast flowing rivers on the vicinity, and normally not much wind so no windmill like in oz (but we do get small fierce whirlwinds in the hot seasons, normally just before it rains).

I have looked up the article and got some mathematical design data from a paper by the Ethiopian Society of Mechanical engineers (yes really). I will contacts booksellers in the uk to see if they can source the book in question.
I'll let you know how much this "plastic" ram costs. PVC plumbing is widely available here in Thailand and its very cheap. Foot valves are an obvious candidate. I am wondering if an air receiver is needed given the inherent flexibility of pvc piping. Will try it out.

 

[barryadamson]

Brain
I would use steel piping & definitely the air vessel. The hydraulic ram works on water hammer & the pressure rise due to a shut off of 1 m/s is 100 m & only about 40 m for PVC.

It may be worth a try to use PVC (for cost) but I think you will go back to the conventional method (steel pipe & air vessel).

Regards
barry a

 

[brianslater]

Hi Barry
Ye I agree that the steel pipe and air vessel is ideal, but its expensive in comparison with pvc. The pumping heights above the dam basin are no more than 20m. I will try using clear plastic tubing on the discharge as this is many times more flexible than the pvc suction pipe. Its just a passing thought, as the discharge tube can act as an energy storage device instead of an air cylinder - maybe? will keep you posted, and can send jpgs if you wish