Well, here it is working ... Manufacturer P Maderni, Paris. Patent describes how carbide in an inner cylinder with a closed base is close-fitting with a second brass cylinder (in the way that fishing rod ferrule joints mate up). This second brass cylinder has a dome, out of which an acetylene outlet tube is tipped with the burner. The assembly of the two cylinders is dunked in an outer tinplate pail containing water, which percolates through the interface between the brass cylinders and enters the carbide chamber through a line of pinholes in the cylinder wall. Manufacturer’s plaque on the water tub. An idea of scale, alongside a Veritas Suberb. Purchased, it had been painted green and needed some work The water pail was holed in a number of places. The mounting loop was missing from the clamping screw. I made one from 6mm diameter brass rod and silbrazed it to the steel screw. To repair the holed water pail I used POR15 metal prep solution to halt the rust then a coating of JB Weld plastic bond to seal base and inner wall, bridging the holes and making the vessel watertight. The patent drawing depicted a hanger hook and I made one to the pattern shown - foreground in this photo. The hook’s a versatile design. The patent describes how the spike can be poked into ‘walls’ (mortar joints presumably) and it does this trick on my patio table ... ... or hangs from a tree. Jobs done, I fuelled up with calcium carbide. About a quarter of the maximum capacity here - the residue when the chemical reaction with water takes place expands. Water is poured in here. Night fell. It’s an effective lamp. In the more common type of carbide lamp water is dripped onto the carbide and the frequency of the drips can be regulated to control burner output to some extent. With this lamp, I found that how much I filled the water reservoir had a bearing on burner output. A greater volume and therefore ‘head’ of water resulted in more water percolating through to the carbide per minute and a correspondingly increased rate of gas generation - a brighter light, but reduced running time. I found a happy medium, where the amount of carbide I pictured kept the lamp running for four hours. A full load and the duration could be easily doubled or tripled. John
Very interesting, well presented and an excellent fettle. I learnt something new so always good. Thank you for your efforts and for sharing. Chris
Interestingly, a further patent search disclosed this later Maderni design, which incorporates the carbide lamp I have and a sophisticated reflector arrangement, controlled by a chain, that could be angled and act as a shutter - so a signalling lamp, but this too ... The patent drawing.
Thank you. A very enjoyable read, hours of research in this post. I have learnt something new today. Every day is a school day!
