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Hot and cold blast iron
72
Mechanics, Ph3tsies, and Chemistr~d.
be dressed passing over the inclined plane B - - a continuous stream of waste going over the end of frame into eisteru F ~ a n d a continuous stream of clean, or dressed, ore being deposited in cover E ; and it is tbund that no other method yet adopted can either produce the same effect, both as regards the high produce of the cleaned ore, or the impoverished state of the waste, iu which particular point the great saymg is--as, let the person attending it be ever so negligent, no ore is being wasted so long as the water wheel is at work ; while, in the old method, there is a great quantity of ore which finds its way to the taft of the frame, through the negligence of the party using it. O~l reference to our preeedit~g column, sufficient testimonials will be found tosatisfy the most prejudiced against innovation on the good old plans, that these frames effect a saving in labor, in dressing ores, of from 10 to 20 per cent. ; while it is generally eonsidered, by agents and dressers, who have had them in use for months, that the savfl~g in ore is of considerably greater importance than that saving in labor. Lond. Min. Jour.
Itot and CoM Blast Iron. Mr. R. Stephenson, the engineer, has been making a series of experiments upon the relative strengths of hot and cold blast iron, the result of which will be a complete revolution in the iron trade. Hitherto, cold blast iron has brought a higher price, and has been considered in every respect superior to hot blast. Previous, however, to the construction of the high level bridge at Neweastle-upon-Tyne, intended to connect the York and Newcastle with the Newcastle and Berwick Railway, Mr. Stephensou caused more than one hundred experiments to be made with the various sorts of pig iron :--the result of which has been to prove that hot blast is superior to cold, ill the proportion of 9 to 7 ; and, moreover, that pig iron No. 3 is better iron than No. 1, which, up to this time, has sold much higher in the market. Athenaeum.
Incrustalion of Boilers. Mr. Lamb, superintendent of the Peninsular Steam Navigation Company's steamers at Southampton, at the late meeting of the British Association, gave an account of a mechanical apparatus he has employed for the purpose of preventing incrustation of steam-boilers. It may be defined as a self-acting blow-off apparatus. He has a theory that ,,blowing off" should take place near the top of a boiler rather than from the bottom. He conceives that the carbonate of lime floats by means of small bubbles of steam adheri~ng to each particle of lime. His contrivance consists of a large copper float closing the orifice of a blow-off pipe in the boiler. When the water has risen above a certain height, the blow-off valve is opened by the float, and so delivers the boiler of its excess of water. This hot water passes through a cylindrical chamber round the feed-water, so as to heat it on entering. The apparatus is simple, and is stated to have worked perfectly well. Lond. Min. Jour.
Mechanics, Ph3tsies, and Chemistr~d.
be dressed passing over the inclined plane B - - a continuous stream of waste going over the end of frame into eisteru F ~ a n d a continuous stream of clean, or dressed, ore being deposited in cover E ; and it is tbund that no other method yet adopted can either produce the same effect, both as regards the high produce of the cleaned ore, or the impoverished state of the waste, iu which particular point the great saymg is--as, let the person attending it be ever so negligent, no ore is being wasted so long as the water wheel is at work ; while, in the old method, there is a great quantity of ore which finds its way to the taft of the frame, through the negligence of the party using it. O~l reference to our preeedit~g column, sufficient testimonials will be found tosatisfy the most prejudiced against innovation on the good old plans, that these frames effect a saving in labor, in dressing ores, of from 10 to 20 per cent. ; while it is generally eonsidered, by agents and dressers, who have had them in use for months, that the savfl~g in ore is of considerably greater importance than that saving in labor. Lond. Min. Jour.
Itot and CoM Blast Iron. Mr. R. Stephenson, the engineer, has been making a series of experiments upon the relative strengths of hot and cold blast iron, the result of which will be a complete revolution in the iron trade. Hitherto, cold blast iron has brought a higher price, and has been considered in every respect superior to hot blast. Previous, however, to the construction of the high level bridge at Neweastle-upon-Tyne, intended to connect the York and Newcastle with the Newcastle and Berwick Railway, Mr. Stephensou caused more than one hundred experiments to be made with the various sorts of pig iron :--the result of which has been to prove that hot blast is superior to cold, ill the proportion of 9 to 7 ; and, moreover, that pig iron No. 3 is better iron than No. 1, which, up to this time, has sold much higher in the market. Athenaeum.
Incrustalion of Boilers. Mr. Lamb, superintendent of the Peninsular Steam Navigation Company's steamers at Southampton, at the late meeting of the British Association, gave an account of a mechanical apparatus he has employed for the purpose of preventing incrustation of steam-boilers. It may be defined as a self-acting blow-off apparatus. He has a theory that ,,blowing off" should take place near the top of a boiler rather than from the bottom. He conceives that the carbonate of lime floats by means of small bubbles of steam adheri~ng to each particle of lime. His contrivance consists of a large copper float closing the orifice of a blow-off pipe in the boiler. When the water has risen above a certain height, the blow-off valve is opened by the float, and so delivers the boiler of its excess of water. This hot water passes through a cylindrical chamber round the feed-water, so as to heat it on entering. The apparatus is simple, and is stated to have worked perfectly well. Lond. Min. Jour.