Glue, gelatine, animal charcoal, phosphorous, cements, pastes and mucilages

by F. Dawidowsky

Moulding the refined phosphorus. It has long been the custom to mould phosphorus into the shape of sticks formed by the aid of a glass tube open at both ends, one of these being placed in molten phosphorus covered by a stratum of warm water. The liquid phosphorus is sucked by the operator into the tube until it is quite filled. The lower opening of the tube being kept under water is closed by the finger of the operator; the tube is instantly transferred to a vessel filled with very cold water by which the phosphorus is solidified. It is removed from the glass tube by pushing it out with a glass rod or iron wire while being held under water.

Independent of its danger, the method of moulding above described is not suitable for the manufacture on a large scale, and various contrivances have been introduced for this purpose; the apparatus constructed by Seubert being much used. It consists of a copper boiler fitted on a furnace. To the flat bottom of this boiler is fitted by hard solder an open copper trough communicating with a water-tank. In the boiler is fitted a copper funnel provided with a horizontal tube. This portion of the apparatus is intended for the reception of the phosphorus. At the end of the horizontal tube is placed a stopcock, while the portion of the projecting mouth of the tube beyond the cock is widened out and fitted by means of bolts and nuts, with a flange-like copper plate, into which are inserted two glass tubes. Into the copper trough is let a wooden partition, which serves the purpose of supporting the glass tubes as well as of preventing the communication of the hot water in the boiler and a portion of the trough with the cold water of the tank and the portion of the trough nearest to it. The phosphorus having been introduced in the boiler, the water is gently warmed so as to cause the fusion of the phosphorus. As the warm water reaches to the wooden partition, it is evident that on opening and closing the cock at the end of the horizontal tube, some phosphorus will pass through and flow out of the glass tubes, but that remaining in these tubes will solidify, and on opening again the cock at the end of the horizontal tube, the solid sticks of phosphorus may be removed from the glass tubes by taking hold of the piece of projecting phosphorus, the phosphorus being immediately immersed under water in the tank, and kept there protected from the action of the light.

Notwithstanding its apparently very practical arrangement, Seubert’s apparatus possesses many disadvantages, the principal drawback to its use being that the phosphorus-sticks frequently stick so firmly in the glass tubes that the operation of moulding has to be interrupted, the tubes removed, and the phosphorus stick pushed out with a stout wire. Furthermore, the melted phosphorus in flowing in frequently causes the glass tubes to crack.

Hence many factories have returned to the old method of moulding by sucking the fused phosphorus into glass tubes. To render this operation perfectly free from danger, the apparatus shown in Fig. 55 has been devised, by means of which a larger quantity of phosphorus can in a short time be moulded into sticks.

A hollow prism, P, of stout sheet-iron is fitted at its lower end with 8 to 12 short tubes. In the latter are inserted air-tight, by means of rubber, 12 glass tubes, G, each about 3¼ feet long and somewhat contracted at the lower end. Two iron rods, E, are fitted to the prism and, by means of suitably-shaped pieces of cork, serve to hold the glass tubes in their proper position. To the back of the prism is secured a rubber tube, L, which communicates with a small air-pump, and to the upper surface of the prism is fixed a handle.

Fig. 55.

The phosphorus to be moulded is fused in a shallow vessel of such a shape that a portion of it is covered only about 2 inches deep with water. The glass tubes are placed in the fused phosphorus and the air is sucked from them by means of the air-pump; the external air-pressure forcing the fused phosphorus into the glass tube.

The tubes are now sufficiently raised to allow of a rubber plate being pushed under their mouths in the shallower portion of the vessel. The rubber plate is pressed against the tubes and the entire apparatus placed in a vessel filled with cold water. The phosphorus solidifies very rapidly in the lower narrower portions of the tubes, and the latter are immediately detached from the prism and replaced by others. The phosphorus when entirely cold is pushed from the glass tubes by means of a wire or wooden stick.

In some factories the phosphorus is moulded in wedge-shaped sheet-metal boxes. In packing two such wedges are laid together with their longitudinal sides so as to form a prism.