Swiss-PEP

Aqua Alimenta uses the Swiss-PEP – a purely mechanically activated treadle pump – in or-der to provide an easy transportation mode of water. This pump is at the core of the system and eases the transportation from the waterholes to the acreages; additionally it relieves people from the long and exhausting task of carrying buckets to the fields.

In use at thousands of small farms

The Swiss-PEP is being used wolrdwide by thousands of small family farms for the watering of their vegetable gardens.

It is produced locally and can be repaired independently by the users

After a careful local training, the pump can be created by local craftsmen with local materials. It is built in such a way that many pieces can be repaired or replaced by the farmers them-selves.

Efficient!

At a human work performance of 50 Watt, 60 litres of water can be extracted every minute on a height of 3 meters from wells, rivers, lakes, ponds and other water sources. Years of experience have shown that families can improve agricultural yields and reduce watering time by using the treadle pump.

A simple and robust construction

The two-part pump housing, which is built out of concrete, is constituted of a pump block and a support block. The pump block is equipped with two cast-in PVC cylinders, pistons, valves and an intake socket. The metal parts cast in the support block serve as support elements for the two pedals. The water is sucked from the source via a suction pipe by the movement of the pistons.

The Swiss-PEP is technically and ergonomically mature and has proven itself in the field for many years. It was scientifically tested and got an award from the Hochschule für Technik und Architektur in Luzern.

Working principle

The water is sucked from an available source to the pump through an under pressure in the system. Inside the Swiss-PEP, the water is further transported via a sophisticated mechanism and lead to the irrigation systems on the fields through the pumping action.

Impressively simple - also on the inside

The principle of operation inside the pump is as sophisticated as simplistic. The dual function of the two built-in pistons is a unique feature of the pump. These serve on the one hand as an outlet for the incoming water within the pump, on the other hand as a seal that prevents the backflow of pumped water once in the upper half of the cylinder, and it ultimately allows its transport. To this end, the pistons are provided with an annular tube that “floats” within the piston assembly. This annular tube shifts depending on the motion direction of the pistons. It lets water enter when the pistons move towards the bottom, and seals it when the pistons move to the top, as the water pushes the tube down.

Cross-section through the cylinder block

Hint: The pistons move in diametrically opposed directions due to the pedal drive, however the functioning is the same for both cylinder parts.

 

Downward movement of the piston

When the piston moves downwards, the pressure shifts the “floating” tube to the top of the piston encirclement and thus lets water enter into the upper half of the cylinder.

The downward pressure simultaneously ensures that the simple inlet valve, which is attached to the lower cylinder edge and is constituted of a floating piece of rubber mat, is pushed against the inlet opening – the water that once flowed into the cylinder is thus prevented from flowing back.

Upward movement of piston

In contrast, the annular tube closes the Piston passage during the upward movement of the piston; the water from the upper half of the cylinder is pumped to the outlet, and is thereby fed to the irrigation systems on the fields. Simultaneously, the pressure on the rubber mat on the cylinder bottom is reduced - the inlet opens and water is drawn from the suction pipe into the cylinder

Background – From a prototype to the swiss-PEP thanks to dedicated engineers

 At the end of 1993, the innovative engineer André Zumstein created the first prototypes of the Swiss-PEP. The dilemma that motivated him and a group of co-thinkers: a rusty small-scale irrigation pump from India. And 700 million malnourished farmers.

The prototype needed to be corrosion-resistant, easy to maintain and purely mechanically operated. The dedicated group faced this difficult task with success. Today, the Swiss-PEP is technically and ergonomically mature and has proven itself in the field for many years. She has been scientifically tested and awarded by the Hochschule für Technik und Architektur in Luzern.

 

Facts and Figures

Swiss-PEP

  • Made from locally available materials and cheap
  • Independently repairable by small-scale farmers
  • Over 15 000 copies installed worldwide on plots of small farmers in the past 18 years
  • At a human work performance of 50 Watt, 60 litres of water can be extracted every minute on a height of 3 meters from wells, rivers, lakes, ponds and other water sources
  • The small-scale farmers save several hours of watering time thanks to the facilitated transport of water
  • Small farmers can increase their acreage and improve their yields per plot