Help find water taps for handwash stations - inexpensive & durable
Good day, all,
I have looked high and low for a durable, inexpensive low cost tap that can be used in gravity fed handwash stations, to little avail. This appears to be a major stumbling block to primitive school and home handwash setups. If you know of any, please post them here - or provide links, leads to some.
Scenario: youngsters or adults walk up, push a button or pull a lever (which is easily cleanable, or washed by the water flow) and the water sprinkles onto their hands for a short time, then turns itself off. It works typical low-pressure gravity fed system (e.g. tank raised a few meters),
It must be easy to manufacture in each developing country which restricts imports. Ideally they would be made of inexpensive materials that can be found in most cities in developing countries; or from inexpensive moulds that can be used to cast plastic etc.
Here is what I've found so far:
USA & Chinese valves you pull down, which shut off automatically, but they require 20-30psi, not operate at very low pressure; example: Hippo one-touch tap; video: www.hihippo.com/en/2012en/talktous_02.html
hy2u - plastic bag, inside decorated cloth bag, with ball valve carved from wood or other material: http://www.hy2u.net/content/technological-perspective___________.... and
the most promising so far, Impex 10092-2V Calf nipple 1/2" http://www.impex.nl/en/category/35/cattle_bull_nipples.html (because people who raise cattle may perhaps use the same tap for humans and cows). I am corresponding with them.
What options have you found? In what countries and regions are they available? How reliable in the field are they?
Cheers, Stew Martin Rotary, Wasrag and RC Seaside
Try Talbot Taflo: http://www.tycowaterworks.com/pdf/VALVES/Talbot%20Talflo%20Valve%20Data%20Sheet.pdf. These don't have the water saving spray feature that you are after as they are design for standpipes, but they are robust and carefully designed so that they cannot be jammed open, which is a problem where people want a 'hands free' filling operation, but then waste water when their container is full.
I faced the same issue a few years ago when specifying replacements for Talbot Talflo taps which after several years of use had worn sloppy, are not cheap and are heavy for air transport. People operating these taps have a lot of time to think how to fix them open while they wait for their containers to fill and I have seen them tied up open with bits of vegetation string.
The option I found was from the suppliers of much of the emergency water treatment kit for OXFAM: Evenproducts Ltd (now acquired by KAR UK Ltd ??). Their taps (EVenflow valves) re a cheaper option and are much lighter in weight. They are mounted on a horizontal spigot and have a horizontal push to open action and a spring assisted closure. I sent a bunch of these out to DRC some years ago but have not heard how they fared - so I need to check on this.This design is also susceptible to being tied in the open position. See http://www.evenproducts.co.uk/pdfs/Evenflow%20Valve%20Apr11.pdfhttp://www.evenproducts.co.uk/pdfs/Evenflow%20Valve%20Apr11.pdf
I too spent some time thinking how to make a simple, cheap tap but I never refined it. One of the simple options was to pinch a flexible tube but the life would inevitably be short and this is where one of the the trade-offs can be found: cheap but low life or expensive and longer life.....
I appreciate this does not meet your design criteria but is an option to the Talbot Talflo tap.
Have you looked at the Tippy Tap?
All the best. //Steve
I have found this paper: Tap Design Review in Emergency Water Supply – http://www.watersanitationhygiene.org/References/EH_KEY_REFERENCES/WATER/Piped%20Water%20Schemes/Piped%20Water%20Schemes%20General/Tap%20Design%20Review%20Thesis%20(Cranfield%20University%20-%20Gildas%20Le%20Hyaric).pdf It is a bit out of date, but gives a good background to things to look out for and possible sources.
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