US746814A - Method of extracting moisture from air for blast-furnaces and converters. - Google Patents

Description

No. 746,814. PATENTED DEC. 15, 1903 J. GAYLEY.

METHOD OF EXTRAGTING MOISTURE-FROM AIR FOR BLAST FURNACES AND CONVERTERS.

' APPLIOATION FILED SEPT. 22 1894. N0 MODEL. 2 SHEETS-SHEET}.

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\ UNITED STATES Patented December 15, 1903.

PATENT OFFICE.

.JAMES GAYLEY, OF BRADDOOK, PENNSYLVANIA.

SPECIFICATION forming part of Letters Patent No. 746,814, dated December 15, 1903.

Application filed September 22, 1894.

To all whom away concern: Be it known that 1, JAMES GAYLEY, of Braddock, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Methods of Extracting Moisture from Air for Blast-Furnaces and Converters, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming part ofthis specification, in which- Figure 1 shows in elevation, partly in vertical section, apparatus adapted to the practice ofv my invention. Fig.2 is a plan View, on an enlarged scale, of theair-refrigerating apparatus, one of the chambers being shown in horizontal section. Fig. 3 is a side elevation of the same, partly in vertical section.

My present invention is a subordinate improvement upon a method of feeding air to blast-furnaces or converters, for which I have already obtained Letters Patent of the United States No. 527,844, dated October 23, 1894, in which I claim-broadly the method of feeding the air-blast to blast-furnaces or converters, which consists incooling the air artificially to 0 centigrade, thereby causing its moisture to be eliminated or reduced to a small. and practically uniform percentage, feeding the dried air under compression into the furnace'or converter, and maintaining it constantly under compression from the time it leaves the blowing-engineuntil it enters In said 1 patent the apparatus which I show and describe is constructed and arranged so that the air is compressed before its moisture is extracted, although the method claims of said application are not limited thereto. I have discovered that material advantages result if the cooling and drying of the air are performed before it is compressed. As stated in the specification of my said patent, the successfulconduct of all metallurgical operations depends to a great extent on the uniformity of the various materials used in the process. In, operating blast-furnaces and steel-converters one of the most disturbing influences is the varying amount of moisture in the atmosphere, since in both these processes a large amount of air is consumed for the purpose of oxidation or com bustion. The atmosphere holds in suspension quantities of aqueous vapor varying Serial No. 523,762. (No specimens.)

from .20 to 1.6 per cent., and its presence in these metallurgical operations is injurious not only because it is decomposed in the parts of the apparatus Where high heat is required, and thus absorbs heat, but the fluctuations in the quantity of moisture.carried by the air produce corresponding irregularities in the conduct of the process and in the qualityof the product. In the operation of the Bessemer converters the moisture of the atmosphere and its variations in amountare just as troublesome. Its presence in large quantity causes a cooling of the metal-hath, which interfereswith the uniform conduct ofthe process and often produces wasteful chilled heats. All these sources of irregularity and expense in metallurgical operations are eliminated by use of my invention, by means of which I furnish for. the furnace or converter an air-blast practically free from atmospheric moisture.

In order to fully understand the application I of this device, I would explain that it is intended to be used with blast-furnaces for the smelting of ores, with steel-converters for the conversion of iron intosteel; In all of these the air is used solely for the purpose of oxidation or combustion. Blast-furnaces are now constructed with a height of ninety feet and a diameter ofItw'enty-two feet. These are kept full continuously with a mixture of fuel, ore, and flux, and these odor great resistance to the penetration of the blast, which is admitted at the bottom. It notuncommonly requires a pressure of fifteen to twenty pounds per square inch in the air-blast to penetrate this column of material. Likewise in the converter the air is forced through a bath of metal, which frequently weighs fifteen tons, and requires a pressure of twenty-five pounds per square inch .in the blast for economic conversion.

In the practice of my invention I remove the moisture from the air and render it dry, or so dry at least that the percentage of moisture contained in the air is small and practically uniform bysubjecting it to artificial refrigeration, so that its temperature shall be reduced to 0 centigrade, whereby the moisture is condensed and may be collected and withdrawn in the form of water, the air being fed to the furnace or converter under compression from the time it leaves the blowingengine until it reaches the furnace.

Referring now to the drawings, 6 is the pipe through which the atmospheric air is admitted to the cooling apparatus. This pipe may be extended and cooled by water or other fluid, preferably externally, if desired. From the pipe 6 the air passes into a chamber 7, which is made larger to give a greater area of contact, in which is a series of pipes, as shown at 8, which extend across the chamber and at their ends open into chambers shown at 9 and 10. By reason of its greater conductivity of heat the pipes should preferably be made of copper. The water or other fluid for cooling the chamber 7 is admitted by a pipe 12 and after passing through the chamber 10 and thence through the pipes 8 emerges at the outlet-pipe 11. The air being under a constant suction by the engine does not expand on entering the chamber 7. A partial deposition of its contained moisture takes place, which is reduced to a mist by contact with the refrigerating-surfaces of the pipes. After the air has passed through the chamber 7 it may enter a second chamber 13. Chambers 7 and 13' are similarly constructed, except that in chamber 13 I prefer to obtain a better chilling effect by the use of anhydrous ammonia .as the cooling agent, and therefore construct the pipes 8 of iron. The cooling agent is preferably anhydrous ammonia furnished by an ice-making. machine of suitable design, which on evaporation produces a very low temperature-about below zero.

centigradethough other refrigerants producing intense cold, such as carbonic anhydrid, may be employed. The cooling liquid passes through the chamber 13 in the same manner as described for chamber 7, and is removed by suitable pipes, as shown. The entering air is cooled by passing through the chamber 7, and in the chamber 13 under theintense cold produced by the ammonia the temperature of the air is reduced below the freezing-point,so that its contained moisture is precipitated on the outer surface of the pipes.8 and collects at the bottom of the chamber, from which it may be drawn oif through suitable pipes. When using a refrigerant, such as anhydrous ammonia, the liquid absorbs heat from the air and is converted intoagas. It is subsequently cooled and restored to a liquid state for further use. It frequently happens that under the intense cold of the expanding ammonia ice is formed on the pipes 8 in chamber 13, and it may be found desirable to construct the chamber 13 in duplicate, as shown in Fig. 2, so that when ice is formed in one chamber the cooling process may be diverted to the other chamber In Fig. 2 are shown valves 21 fordiverting the air from one chamber to another. The pipe 22 may also be provided with valves, if found advisable. In order to provide against any of the precipitated moisture being carried along in suspension by the refrigerated air, I prefer to employ a chamber 16, containing a series of grids 17 with .small metal ribs and preferably placed in a slanting position. These grids catch the suspended moisture or water, which can be removed through suitable drain-pipes. The chamber 16 is made of sufficient size, so that there is no retardation to the air due to interposition of grids. Having been cooled in the manner above described and the moisture extracted, the air is delivered to the blast-engine, from which it is delivered to the blast-furnace or converter through the various pipes and passages equal to the operation.

In Fig. 1, 18 is the blast-pipe conducting the air to the hot-blast stoves, from which it passes into pipe 19, which conducts it into the blast-furnace, Fig. 1. 20 is the pipe which conducts the air from the blast-engine to the steel-converter. There are some advantages in treating the air for removal of its contained moisture before it is admitted to the blowing-engine, owing to the fact thatthe compression increases the temperature of the air very rapidly, since air at an atmospheric temperature of 60 after passing through an engine and compressed to twelve or thirteen pounds obtains an increase in temperature of about 150. Consequently when the air is treated atatmospherictemperatureitrequires a less cooling efiect to reduce it to zero centigrade and less expenditure for cooling appliances. Besides,air at higher temperatures holds the moisture more tenaciously. Another advantage possessed is that the blowingengines are made more efficient, as the air being cooled to a low temperature and its moisture extracted each cubic foot of air delivered by the engine is richer in oxygen and more suitable for combustion; but the main advantage consists in its requiring a much less expensive cooling apparatus, and thereby rendering it more available for manufacturing.

Many forms of apparatus may be used in the application of this invention in order to apply it to existing conditions. It is desirable to have the air in contact with pipes as long as possible, and for this purpose large chambers like rooms in which the cooling.- pipes would act as a partition may be found desirable or it is possible to do all of the cooling with ammonia alone, although it is not so economical, or the cooling fluid may be ammonia in one chamber and brine in the other, and with smaller volumes of air only one chamber may be used. The cooling-pipes,

may also be constructed in the form of a coil and of such length as to derive the most economical results from the refrigerant.

It will be readily observed that on account of the air being constantly in rapid motion,

IIO

due to the suction of the engine and the enormous volume required, the methods usually employed for extracting a portion of the moisture from small volumes of air in applying it to drying grain, cooling rooms, 850., are not applicable to blast-furnaces and converters, since in many of these methods the air is allowed to expand, which in itself is the most serviceable refrigerating process and simplifies the operation to a great extent, while in my process there is no substantial expansion of the air prior to its introduction 1 into the furnace.

The mechanical retardation of the current by partitions andgrids is avoided in my device, the grid-chamber being of such area that the space between the ribs is sufficient to allow the volume to pass through without retardation.

In my apparatus the current of cooling fluids passing through a series of pipes is directl y across that of the air-currents, by which I maintain in this short travel a much lower temperature than in such appliances where the currents of air and cooling fluid are longitudinal.

The advantages of my invention will be appreciated by those skilled in the art. By

' rendering the air dry or practically dry by refrigeration, as described above, before it is introduced into the blast-engine and supplying such dry air in large quantities under constant compression to the furnace or converter the amount of moisture is made practically uniform from day to day and from year to year. It is thus made easy for the blast-furnace manager to secure uniformity in the character of metal produced by the furnace notwithstanding varying meteorological conditions and without that close supervision which is necessary in furnace practice heretofore in common use.

I claim- The method of feeding air to'blast-furnaces or converters, which consists in drawing the air through a chamber and cooling it in said chamber to 0 centigrade, thereby causing its moisture to be eliminated or reduced to a small and practically uniform percentage, thereafter causing the dried air to pass into the blowing-engine, then feeding the dried air into the furnace or converter, and maintaining it constantly under compression from the time it leaves the blowing-engine until it enters the furnace or converter; substantially as described.

In testimony whereof I have hereunto set myhand.

JAMES GAYLEY.

Witnesses:

W. A. HOLLAND, J. N. GRIFFITH.

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