It will be evident to most technicians and trades people, that there are a near infinite number of ways to assemble a sprinkler head and basin for washing hands. We will not waste much time here on that aspect of the handwash stand, but rather describe how to build and connect the simple footpump that provides the main utility of this design.
Most experienced technicians will see that there are many possible configurations for this assembly. Put simply, we have attempted to design this device to use commonly available components. Some of the simpler components, therefore, receive scant mention here, while we will attempt to provide a little more discussion of the foot pump.
A variety of methods can be used to assemble the stand. We have illustrated here, models built from reinforcing rod, and from plastic buckets. Other versions can be attached to wooden posts, convenient trees, or walls. Please do not forget to provide suitable soap trays, support for soap-on-a-rope, holder for liquid soap, or a combination of the above.
The basin itself consists of the spout end of a 5 gallon (20 litre) potable water container. It is easily cut with a knife, but perhaps easier still with a fine toothed saw.
The spout, or outlet of the basin, fits easily and loosely into the end of a 2″ PVC drain pipe. This carries the water a small distance from the stand, where typically, it can be absorbed into a soakage pit. In a few portable and temporary applications, the drain water can be captured in a bucket and carried to a convenient location for dumping.
The sprinkler head consists of a threaded PVC cap, perforated as shown, with a 1/16″ (1.5 mm) drill bit. It will be helpful if the centre hole is directed vertically, while the holes around the outer perimeter slope very slightly outward. A little experimentation will reveal the most advantageous configuration. The reason for using a threaded cap, is so that it can be removed for cleaning if it becomes blocked.
The piping used need only be about a nominal 1/2″. Where greater toughness is required, galvanised iron pipes can be used. For lighter use, or in private homes, PVC pipes can be used. In many instances, the tubes can be wired to the stand. In the case of the “Bucket Base” seen above, we have made a pair of clips from 3/4″ sch 40 PVC pipe, cut and attached to 3/4″ plywood blocks as shown. The Plywood blocks can be attached by screwing through the wall of the bucket from inside. The clips can be attached to the plywood blocks with two countersunk screws from inside the clip.
A barrel with a bulkhead fitting near the bottom makes a suitable water tank, as seen in the illustration above, and provides sufficient storage to last a considerable time, owing to very efficient water useage.
Flexible connections can be cut from 5/8″ garden hose. Suitable connections for the garden hose can be made with 1/2″ CPVC tubing (which is smaller than PVC), along with suitable thread adaptors, if standard hosebarb fittings are not locally available. See footpump illlustrations below.
The foot pump itself consists of a simple bladder with two check valves serving as inlet and outlet valves respectively. Let us address these two components separately:
We have used 1/2″ gravity-actuated, brass check valves. It would be possible to substitute a spring actuated check valve for the outlet side, but we would suggest using the gravity actuated type for the inlet side; that is the side comming from the water supply tank. We have assembled the check valves with a 1/2″ threaded tee and schedule 80 or galvanised iron close nipples, but again, most technicians will see that there are many alternative combinations that can be used. What is important, is that the inlet valve is pointing into the Tee, while the outlet valve is pointing out of the Tee.
The bladder can be made with motorcycle innertubes (chambre in French). We used 2.75″-3.0″ inner tubes (the other dimension does not matter), which fit neatly over a PVC bushing, 2″ x 1/2″ (or whatever alternate size the tee might be). Please remember that if an inner tube is used for the bladder, then a second layer of rubber, consisting of auto inner tube, shoulde be tacked over the entire bladder assembly to protect the bladder from damage. We’ll add a photo of this shortly. The free end of the motorcycle innertube is doubled over, and clamped between the base board and a block of 3/4″ plywood, as shown. In some instances we have used a strip of unvulcanised rubber in the crimped joint, but have found it not to be absolutely necessary. The screws holding the clamping block can be driven right through the end of the bladder, anchoring it securely.
We show here, a tougher bladder made with old 3″ lay-flat water hose. The resulting bladder is stiffer and slightly slower filling when foot pressure is removed. The lay-flat hose is less elastic and therefore harder to fit onto a suitably sized fitting. Some experimentation may be needed. In our version, a 2″ bushing was too small, so we attached a half of a 2″ coupling over the bushing. Now the 2″ coupling started out too large, and therefore had to be reduced to fit snugly into the hose. We have found it convenient to mount the fitting on a mandrel in a power drill. It can then be eroded with either coarse sand paper, or trimmed with a sharp blade. A future web page will illustrate low tech methods for machining PVC fittings without heavy machinery. In the meantime, if any clarification is needed, your question will be welcome. It will be found that the free end of the lay-flat tubing is stiffer, and might be difficult to double over. In this case, it can be used without doubling, but may benefit by the addition of a narrow strip of unvulcanised rubber such as is found in the repair kit of an Oxfam tank or equivalent. (The amount of this material in one repair kit is likely to serve to build many hundreds of footpumps.)
A rough materials list for our version of the assembly follows:
- Stand, consisting of either welded steel, or One 5 gallon and one 2.5 gallon bucket assembled as shown, or a wall , post, or tree mounted shelf.
- A basin made by cutting the spout end off a 5 gallon water bottle.
- Sufficient 2″ PVC drain pipe, with elbow, to divert the drain water to a suitable soakage pit.
- 1/2″ PVC or galvanised iron pipe to rise form a vertical riser approx 39.5″ (1.0 m) and a horizontal nipple approx. 6″ (15 cm). In the case of galvanised iron pipe, the 6″ nipple can be purchased ready made, but the 39″ piece must be threaded for the purpose.
- 3 no. 1/2″ elbows (90), PVC or galvanised iron, depending upon the pipe selected in (4).
- 5 no. sch 80 or galvanised iron 1/2″ close nipples. (4 if PVC is used above).
- A 1/2″ male pipe thread adaptor for PVC, if PVC was used above.
- A 1/2″ threaded PVC cap.
- A 1/2″ threaded tee.
- 2 no. 1/2″ brass gravity operated check valves.
- A 2″ by 1/2″ PVC slip x Female pipe thread bushing.
- A 2″ PVC coupling cut in half crosswise (only required for use with lay-flat hose)
- 12″ length of 3″ lay-flat hose, or 2.75″ – 3″ motorcycle innertube (chambre aire).
- 15″ length of 2 x 6 wooden plank.
- 3 no. 5″ x 1.5″ blocks of 3/4″ plywood.
- 7 no. wood screws, #8 x 1.5″.
- 4 no. CPVC 1/2″ male pipe thread adaptors.
- Approx. 12″ length of 1/2″ CPVC pipe.
- Approx. 60″ of 5/8″ garden hose (depending upon distance from water tank to stand)
- A shut off valve and bulkhead fitting for the water tank (barrel)
- A 200 litre barrel, free of chemical toxins or other contaminants.
Above all, if any of the materials listed are not locally available, use your ingenuity to substitute materials that are. We have not yet made this site interactive, but can be reached at firstname.lastname@example.org, or through the “Contact” page on this site.