PVC pumps
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The name PVC pumps covers a large number of different hand pump designs, which have in common that most parts are constructed out of PVC. PVC is used because it is often cheap, and easy to work with. As PVC is less durable as other materials such as steel, a singe PVC pump should be used by a limited number of people. Because of the low price, PVC pumps are often used as family pumps.
There are many types of PVC pumps, differing in design aspects such as direct action versus lever operated, piston rod versus piston pipe, single or double action, with or without a water seal. The valve designs vary from ball valves, rubber flap/butterfly valves and bicycle inner tube valves to bolt valves, pvc adapter valves, and washer valves.
Examples of PVC pumps are the [EMAS pump], [Baptist pump], the [Canzee pump] and the DTU pump. Some pumps are described in their own Akvopedia articles, reachable by clicking on the links above.
Some pumps, such as the [EMAS pump], [Baptist pump] and [Canzee pump] are deep well pumps, which can pump water from up to XXX m deep. The [DTU pump] is used for extracting water from underground rainwater catchment cisterns.
History and social context
Because of their lightweight and low-cost design, PVC pumps are mainly suitable to be used by families or small groups of families. PVC pumps are not recommended for use by large groups of people, as this will lead to the need of frequent maintenance. An excellent overview of community hand pumps, which are suitable for larger groups, is available at the RWSN website1.
Suitable conditions
| Advantages | Disadvantages/limitations |
|---|---|
| - Low cost - Can be locally produced and sold |
- Not suitable for large number of users - Normal PVC degrades through sunlight |
Technical specification
An important issue with all PVC pumps is the tendency of PVC to become brittle when exposed to direct sunlight for some time. Some pumps, such as the Baptist and EMAS pump, solve this by having a concrete pillar around the PVC tube, and by constructing the handle part out of galvanised steel pipe. Other pumps, such as the Canzee pump, use special UV-resistant PVC. The negative effects of sunlight can be partly avoided by shielding the pump from direct sunlight, by painting PVC parts, or by protecting the PVC in some other way. In Bolivia, a strip of cloth is wound around the PVC parts, and held together with a piece of metal wire.
Operation
The operation of PVC pumps varies from design to design. Most pumps have a handle which is pushed up and down. The EMAS pump pumps water on the downstroke, in which water is pushed up through the piston pipe. This has the advantage that pressure is created, with which the water can be pumped over a distance or to a higher location. When pumped over a long distance, it is advisable to use an airchamber made from a soda bottle to even out the flow of the water, which increases the efficiency.
Maintenance
The maintenance that is needed depends on the design of the pump. In some designs, the bottom valve will need to be replaced periodically. Valves are often made of rubber.
Manufacturing
Many of the PVC pump designs, such as the EMAS and Baptist pump can be made locally. The Canzee pump can also be made locally, but needs UV-resistant PVC tube.
Cost
PVC pumps can be made very cheap. An EMAS pump can be made for about 5$, with 1$ extra for every meter of depth.
Country experiences
Manuals
Movies
External links
- Info on Canzee pump by Bushproof. The brochure on the Canzee pump can be downloaded.
- EMAS pump Akvopedia article
- EMAS website in English
- Low-cost pump alternatives for rural communities in Honduras (rope- and EMAS pumps), SKAT website
- Baptist pump Akvopedia article
- Information on the Baptist pump
- Low cost handpumps for water extraction from below ground water tanks by DTU.