Inventor?

Wed Apr 28 (2004)

New mold for the BathroomToilet-unit

Sat Apr 17 (2004)

Good result today with the new method for making imprints in moist dirt. These imprints are made with the also renewed version of the mold for the big slabs (see info). This new system uses four different parts: the two decorated slabs, a removable cover for each slab, a gutter. into which the two Bathroom floor slabs drain and three thin concrete separating slabs. These three separators are kept in a vertical position at some distance by masoned walls in between, thus making two separated cellars. The middle separator carries the gutter. the outer separators carry the outer edge of the bathroom floor slabs.
The removable cover is part of the bathroom floor slab. It can be taken out to empty the cellar when its content has been left to compost for about half a year. Extensive experience in Vietnam indicates this composting system works well and produces safe compost.

I hope to use this new system in a pilot guided by HSHC in Nairobi within a month from now. In that same time span a lot more work has to be finished as well as a start has to be made with the use of the new workshop in Maastricht.
Today I got assistance from Tom Groenveld, student forestry at Larenstein. Tom plans to make a study trip to Kenya this summer and most probably he will contact HSHC in Nairobi. He wanted to be instructed in the use of the mold to make imprints in the dirt. The pictures show: 1) preparing the site, 2) filling and compacting the mold with wet soil, 3) turning over the filled mold, 4) compacting an dirt ridge around the mold, 5) lifting the mold carefully off and finally looking happily at the accurate copy thus achieved.

Going Wiki

Wed Jan 14 (2004)

New interns, new ideas!

Fri Jan 09 (2004)

When Leonora gave her presentation to an audience of her design school about her internship at Demotech, one her listeners was student Anna Hillman. Anna let herself be informed by Leonora of what she could expect at Demotech and decided to contact me. Could she come for her outplacement and bring her friend design student Clare Cunningham?
This picture of Leonora, Anna and Clare was taken yesterday at Demotech. Good to see how a continuation can grow in the flow of work and ideas, both energized by the potential design has for solving problems on poverty and the environment.
Bram the Vries, with a technical background, but now studying antropology at Utrecht, was not content with the roller I planned to use in the new rope pump set-up.

Technology for Democracy

Tue Dec 16 (2003)

How it works in Maastricht

Mon Nov 24 (2003)

BrickStove testing

Mon Oct 27 (2003)

Blue and reddish gas flames where sucked into the flame tunnel

At the workshop of Hans Baarslag in Wierden, the BrickStove waited for a test. New to be tested were three items:

• the lining of the fire box made from thin stainless steel sheet (0,5 mm),
• the new set up of the conical funnel, the 'catch' where the wood from the container gets stuck, while sliding into the fire box,
• the ash tray, also folded from sheet metal, that takes part in guiding the burning gassified wood into the "flame tunnel".

Thanks to the link we got from Sasha I now understand better the two phases of wood burning: first the gasification of the wood, followed by the burning of the gas. Air (oxygen) for such secondary burning is still available in the gas mix or streams in through a second opening.
Actually these two phases could well be observed through a glass window: wood, while it was burning and smoking remained stuck into the catch. From time to time charred peaces fell off, lining the ash tray with burning charcoal. Blue and reddish gas flames where sucked into the flame tunnel. (see top picture)
The steel sheet lining for the bricks, the shape of the 'catch', the ash tray and the entrance to the flame tunnel, all seemed to function as foreseen. However not so the in-flow of air.

So we reconsidered the idea of pre-heating air, similar as is done in steel furnaces. As the BrickStove is build now, cold air from outside is pre-heated when it flows along a metal separation in the flame channel. It then flows under the ash tray and enters the fire at the front, the place where the window is positioned.
This functions only partly. Because the fuel (wood) container still has a very rough fit in the top of the BrickStove, a part of the air sucked in by the ventilator, leaks in through this bad fit.

rough scheme of the new setup

Joel Fransen, Demotech's new intern from the Design Academy in Eindhoven, suggested to make this accidental air leak the one and only entrance for fresh air.
This is a nice kind of break-through idea, upsetting the present basic set up, but giving another simplistic layout in return. With Hans I planned to build a second stove in this way (see rough scheme of the new setup).

1. Fuel container, filled with anything solid that will burn.
2. The conical funnel, the 'catch' where the wood from the container gets stuck, while sliding into the fire box.
3. Flame tunnel and interior space where the burning gasses transfer their heat to the stone exterior.
4. Exhaust to ventilator. Forced draft sucks in the air at the fuel container, blows it outside.
5. Brick exterior heats up while the fuel container feeds the fire. Its outside radiates its heat outwards for a long period after the fire is extinguished.
6. Top of metal sheet can be removed for inspection and repair.

Roller development

Sat Oct 18 (2003)

Prototypes: strips, rings, disks

The test rig of the rope pump has many new components. In fact only the electric engine, its drive disk and the big two meter diameter wheel, that it drives remain from the first setup. As the big wheel is not round at all (it has 12 corners), it needs a roller to keep the tension on the rope steady, specially the unloaded part, moving back to the electric engine.
In the old setup a sort of lightweight pulley folded from thin aluminum sheet did the tensioning. This worked fine, but the pulley was to difficult to make.

How the strips fit into the disks

Together with Bram de Vries I tried to simplify the making of this tensioning roller. We started out with a cylinder of bamboo slats, woven into a strip (left in picture). We found this too heavy and side ways flexible. For the bearings we had a woven construction in mind. Sideways stability was achieved with less bamboo by tying it zigzag on two rings wound from wire. Stability was perfect, but the woven bearing was difficult to make. (middle position, woven bearing removed).
Amazingly easy it proved to be to insert the bamboo sticks in a zigzag way into disks cut from a bucket. Six small square holes and an shallow slot in the bamboos did the trick. The lower picture shows this detail
Puncturing the disk in the middle with a piece of wire results in the creating of the bearing as well as of the axle.