All these institutions are performing a great regenerative work, and the tribulations and disappointments of the last decades of the 19th century were not all loss.
15) employed for melting glass are usually heated with gas on the " Siemens," or some similar system of regenerative heating.
These small furnaces are frequently arranged for direct coal firing, but regenerative gasfired furnaces are also employed.
The fusion of sheet-glass is now generally carried out in gas-fired regenerative tank furnaces.
With producer gas it is necessary to pre-heat both the gas and the air which is supplied for its combustion by passing both through heated regenerators (for an account of the principles of the regenerative furnace see article Furnace).
(b) Both the producer gas and the air are heated before they enter the combustion chamber, as in the Siemens system of regenerative firing.
Knowing this, and having in the Siemens regenerative gas furnace an independent means of generating this temperature, the Martin brothers of Sireuil in France in 1864 developed the open-hearth process of making steel of any desired carbon-content by melting together in this furnace cast and wrought iron.
In their place the regenerative stoves of the Whitwell and Cowper types (figs.
The general plan of the open-hearth process was certainly conceived by Josiah Marshall Heath in 1845, if not indeed by Reaumur in 1722, but for lack of a furnace in which a high enough temperature could be generated it could not be carried out until the development of the Siemens regenerative gas furnace about 1860.
These regenerators are the essence of the Siemens or " regenerative furnace "; they are heat-traps, catching and storing by their -11, Ton Traver 7s 20 Tan Tra y.
In the intermittent system the waste heat can, it is true, be utilized either for raising steam (but inefficiently and inconveniently, because of the intermittency), or by a regenerative method like the Siemens, Fig.
This regenerative heating is similar in principle and effect to that obtained by means of the shaft and ring kilns described above.
There are a great number of methods of applying the regenerative principle which vary only in detail.