2.1- Preliminary work

His next serious attempt was carried out in Lisbon. This second patented invention, a tracking section of a paraboloid and a solar furnace (patents [11,12,13]- basically translations of each other) can be seen in some of the figures reproduced below. The remarkable thing about this invention is the fact that it achieves a very high concentration factor, with full separation of the optics from the furnace.

A conceptual leap, as explained in the patent, is the fact that in previous 3D solutions radiation got to the focal zone from all sides, never allowing for sufficient concentration to be achieved on its outside walls (see Mouchot, Fig. 1), while taking only a paraboloidal sector allows for the maximum concentration achievable with it to be redirected into furnace Z for direct effect on the substances to process or heat. The built in flexibility of motion always ensures that reflected rays are directed at all times into the furnace Z. In modern terms we can see that the conical entrance aperture to the furnace, ensures a second stage concentration, taking care of reflection and tracking inaccuracies (spillage).

The complete set of drawings show a large number of novel possible combinations of mirrors and furnaces, their relative motions and sun tracking capabilities. Their thorough discussion is beyond the scope of this paper, but their careful consideration, even without any dedicated explanation, is very instructive and enjoyable. The solution of two concentrating mirrors, back to back, moving on the same tracking structure (for instance, drawing 7 within Fig. 6) and the other extreme where the optics and the furnace are combined in a unique set — no rails (drawing 11 of Fig.6) are very interesting. These

drawings show different solutions to track the sun in azimuth and elevation. Use is made of rotation around centre poles to compensate for the Earth’s rotation, with the furnace sometimes moving in a separate fashion, on rails, or as one with the mirror, but always with the possibility of adjusting to the sun’s elevation. But none of these movements could be made in fully automatic way in a modern sense, i. e, in unattended operation, since that would require modern day combinations of tracking motors and sun sensors.

Experiments with one of the possible configurations described in these patents (presumably one with the furnace going on a circular rail) were carried out in Lisbon (March/April 1902). Inaccuracies in the design and mechanical problems, plagued the
prototype. The day of the public demonstration the concentrated radiation destroyed the supporting structure and it was a fiasco!

It must be then that Father Himalaya sought about, quite beyond the fact that he needed to correct the faults with this prototype, that he needed a new idea for a truly practical system able to track the sun, unattended, at maximum concentration. A simple clock mechanism would do the trick, but that required a radically new design. That became the Pyreheliophero, to be described next.

Fig7: The prototype built for the Lisbon tests with what looks like the furnace in the

background