SIEMAN PROCT.SS, TUT.. 





ing an interval of a day even, to produce com- 

 bustion when a new supply is required. The 

 combustible gases having been formed as above 

 described, are made to pass some distance 

 through a large flue, during which passage they 

 are cooled, and made to precipitate any small 

 amount of sulphur which may have ] 

 with them from the coal. They enter the fur- 

 nace purified from all materials noxious in 

 metallurgical processes, and are now prepared 

 for combustion. 



It is necessary to have an excess of pressure 

 in the main gas flue above that of the air, in 

 order to prevent any inward draft, which 

 would produce partial combustion in the gas, 

 thus diminishing the heating power and clog- 

 ging the flues with soot. The gas mnst there- 

 fore be put into the furnace, without a chim- 

 ney draft, which can be done by placing the 

 producers at a lower level than the furnaces. 

 If this is impracticable, another expedient is 

 used. The mixed gases leaving the producers 

 have a temperature of 300 degrees to 400 de- 

 grees Fahrenheit which must in all cases bo 

 sacrificed, as it makes no difference as to the 

 result, at what temperature the gas to be 

 heated enters the regenerators or air chambers. 

 The final temperature will always be that of the 

 heated chambers of the furnace. 



The initial heat of the gaS is therefore made 

 available for producing purposes. The gas is 

 caused to rise about 20 feet, then carried about 

 20 to SO feet horizontally, and let down into 

 the furnace. The tube being exposed to the 

 air causes the gas to cool and increases its den- 

 sity from 15 to 20 per cent., so that the column 

 is urged forward into the furnace by the added 

 weight of the cooler gases. 



Under the furnaces, where the heat is to be 

 used, chambers are built, packed with fire- 

 brick, having open spaces between them. 

 These are four in number, and are called re- 

 generators. They work in pairs, the gas 

 ascending through one, while air ascends 

 through the next. The gas and air enter the 

 furnace, and produce the heat due to their 

 chemical union. At the other end of the fur- 

 nace are similar outlets, connected with the 

 other pair of regenerators. The combined 

 gases, after doing their work in the furnace, 

 pass down these outlets, still retaining a por- 

 tion of their heat, which they impart to these 

 regenerators, and move on to the chimney. 

 The last-named regenerators soon become in- 

 tensely heated by this treatment. The passages 

 between these chambers are supplied with 

 valves and deflecting plates, which act like four- 

 way cocks. By the use of a lever, these re- 

 generators and air ways, which were carrying 

 otf the waste gases after combustion, can 

 instantly be used for conducting gas and air 

 into the furnace, while those which before 

 carried gas and air in, now take out the ex- 

 hausted gases to the chimney. By this simple 

 expedient, an enormous amount of heat wasted 

 in the old furnaces is saved. The gas and air 



entering by the reversal of the valves through 

 the ] to an int--: 



outgoing refuse of combustion, take up what 

 their predecessors had left. : tho 



furnace at a white heat, and there add to their 

 carried heat that due to their mutual chemical 

 action. It is estimated that about 4,000 degrees 

 of heat are thus carried, while 3,000 degrees are 

 taken from the regenerator in passing. This 

 intense heat, if not moderated, would melt 

 down the most refractory materials- of the fur- 

 nace. In this manner the regenerators are 

 alternately heated and cooled at such brief in- 

 tervals as observation may indicate to bo 

 necessary. The result is that a vast economy 

 of heat is effected, and at the same time the 

 quality and quantity of the heat is under tho 

 control of the engineer every moment. The 

 supply of gas depends upon the supply of air to 

 the producer, and can, of course, be stopped by 

 closing the draft. By placing the inlets for air 

 or gas at less or greater distances, the com- 

 bustion in the heating furnaces is made rapid 

 or g-adual at will. So, also, the heat can bo 

 directed upon particular points by nicely- 

 adjusted contrivances, which the ingenious 

 builder will apply for himself. 



The advantages of this system, as claimed by 

 the inventor, and demonstrated in practice, 

 may be summed up as follows : 



1st. It enables the manufacturer to use, 

 profitably, that large class of soft coals which, 

 owing to the presence of sulphur, or the ex- 

 cess of bituminous matter, are now worthless, 

 or only applicable when used. 



2d. It gives unh'mited command of heat, 

 without the intense chimney draft used in the 

 old furnaces, at great cost. 



3d. Great purity and gentleness of flame, 

 which largely diminishes the oxidation or de- 

 terioration of material heated in the furnace, 

 and improves the quality of the product. 



4th. Great increased durability of furnace, 

 owing to the absence of ashes, and perfect uni- 

 formity of heat throughout the works. 



5th. Saving of space within the works, and 

 cleanliness in operating, the fuel being converted 

 into gas outside. 



6th. The complete control of the intensity of 

 the heat, and unlimited command of the chemi- 

 cal nature of the flame, which may be arrested 

 wholly, or changed from a reducing to an oxi- 

 dizing flame, or the reverse, at any moment, 

 tending to facilitate all metallurgical opera- 

 tions. 



7th. The complete consumption of the smoke 

 of soft coal, so that none of it is seen rising 

 from the chimney, rendering this furnace of 

 great v^ue in large manufacturing towns. 



Upon this latter point, Sir William Arm- 

 strong, in a recent paper before the British 

 Scientific Association, remarks : " The produc- 

 tion of smoko is unnecessary and inexcusa- 

 ble. The Sieman process remedies this waste, 

 and removes a great source of public annoy- 

 ance." 



