US2755143A - Method of transporting finely comminuted solids - Google Patents

Description

July 17, 1956 M, M. CUNNINGHAM 2,755,143

METHOD OF TRANSPORTING FINELY COMMINUTED SQLIDS Filed July 11, 1955 INVENTOR.

ATTORNEY United States Patent METHOD OF TRANSPORTIN G FINELY COMMINUTED SOLIDS Marion M. Cunningham, Providence, R. L, assignor to United States Rubber Company, New York, N. Y., a corporation of New Jersey Application July 11, 1955, Serial No. 521,066

2 Claims. (Cl. 302-66) My invention relates to a method of transporting finely comminuted solids through a collapsible hose.

It has heretofore been considered necessary in transporting finely comminuted solids through a collapsible hose to maintain the hose at an internal pressure above atmospheric pressure to hold the hose expanded.

I have found that such is not necessary and that, in accordance with my invention, finely comminuted solids can be transported more efficiently through a collapsible hose by suction if the comminuted solids are first aerated and then positively introduced into the hose.

In accordance with my invention, I use a collapsible hose of such flexibility that the hose will collapse at least 50% but not more than 95% under a differential pressure of approximately atmospheric pressure. I introduced the finely comminuted solid, which has been previously aerated, into one end of this collapsible hose by means of a pump and simultaneously therewith I apply suction to the other end of the hose by means of a second pump secured thereto and operated at a volumetric rate greater than that at which the comminuted solid is introduced into the hose by the first mentioned pump.

Under such conditions of operation, I have found that the comminuted solid will move through the hose more or less in batches with the hose partially collapsed between the batches.

One advantage of my method over those heretofore used is that a much smaller volume of air or gas need be mixed with the comminuted solids in the transportation thereof and that, therefore, the problem of separating the comminuted solid from the gas or air in the ultimate use or storage thereof is materially reduced.

Another very important advantage is that as the batches of comminuted solids move through the hose there is a constant expanding and collapsing of the hose immediately following the moving batches which prevents the caking of the solids on the interior wall of the hose.

Other objects and advantages of my invention will become apparent from the following description when read in conjunction with the accompanying drawing which is an elevational view, partly in section, of apparatus for transporting comminuted solids in accordance with my invention; the apparatus being shown as used in emptying a collapsible container of the general type shown in my United States Patent No. 2,612,924.

Referring to the drawing, the finely comminuted solid flows by gravity from the container C, supported on an emptying device E of the type generally shown in my copending application Serial No. 516,419, filed June 20, 1955, through sleeve valve S into a pipe and across a diagonally extending piece of porous fabric 13 which is clamped between the pipe 10 and a lower supporting plenum chamber 14. Air or gas under a comparatively low pressure is admitted through a pipe 14a into the plenum chamber 14 under the fabric 13 and passes up through the interstices of the fabric 13 and mixes with Patented July 17, 1956 and aerates the finely comminuted solid passing across the fabric to thereby increase the fluidity thereof.

From the fabric 13, the aerated comminuted solid passes to a pump 15, preferably a constant flow pump, and is fed thereby into one end of a collapsible hose 16 which is attached to the discharge side of the pump 15.

The hose 16 is of a gas impervious construction and has a circular cross section when expanded. In accordance with the invention, the hose is of a flexible construction such that the hose will collapse at least 50% but not more than under a diiferential pressure of approximately atmospheric pressure. Expressed in another manner, under a differential pressure of approximately atmospheric pressure, the hose will collapse such an amount that the internal cross sectional area of the hose is between 50% and 5% of the cross sectional area of the hose when expanded. A conventional woven, rubber lined fire type collapsible water hose can be used for the hose 16. I prefer however that the interior surface of the hose be smoother than that of the usual conventional fire hose.

Simultaneously with the feeding of the aerated comminuted solid into the hose 16 by the pump 15, a second pump 17, also preferably a constant flow pump, secured to the other end of the hose is operated at a volumetric rate greater than that at which the comminuted solid is being fed into the hose by the pump 15 to apply suction to the hose. Under the influence of this suction applied by the pump 17, the aerated comminuted solid moves through the hose more or less in batches B with the hose partially collapsed between the batches as illustrated in the drawing and is discharged through the pump 17. For most eflicient operation, the pumps should be operated to provide a lineal discharge of 300 or more feet per minute of the aerated comminuted solid.

If pumps of the same rating are used for pumps 15 and 17, the difference in volumetric rate between the pump 15 and the pump 17 may be obtained merely by operating the pump 17 at higher revolutions per minute. If a pump of a higher rating is used for the pump 17 than for the pump 15, then of course the two pumps could be operated at the same revolutions per minute.

In practicing my invention, very'little air or gas need be mixed with the comminuted solid. A ratio of 10 parts by volume of air or gas to one part of solid is usually sufficient. Consequently, the problem inherent in methods heretofore used of separating the solids from a large volume of air is essentially eliminated. The problem of caking of the comminuted solids on the wall of the hose, which is inherent in methods in which the hose is maintained under above atmospheric pressure is nonexistent in my method, as the walls of the hose are constantly flexed by the expansion and collapsing of the hose as the batches of comminuted solids move through the hose.

My method can be used to transport solids in all directions, i. e., horizontally, vertically, etc. There is, however, some limitations as to the particle size of the comminuted solids which can be efiiciently transported by my method. Generally speaking the comminuted solids should be finer than 20 mesh and preferably finer than about 65 mesh, though particles of larger size can be conveyed if the major portion of the solids are of a particle size as defined. Among some of the materials which can be conveyed when in a finely comminuted dry state are: Portland cement, special cements, limestone, dolomite, magnesite, silica, clays including bentonite, barites, gypsum, cryolite, bauxite, phosphate rock and apatite, iron ore, talc, coal, quick lime, hydrated lime, magnesia, alumina, soda ash, sodium phosphate, litharge, anhydrite, ammonium sulfate, fly ash, furnace and kiln flue dust,

3 bulk resins and plastics, sugar, and t'arinaceous material such as bread and cake flours.

The term aerate" is used herein in its generic sense to denote mixing of the comminuted solid with various types of gases, including air. In most instances it is contemplated that the gas will be air but where the comminuted material being transported is subject to contamination by or presents a hazardous condition in the prescnc of air, an inert gas, such as nitrogen, may be used 7 to aerate the comminuted solid.

Having thus described my invention, what I claim and desire to protect by Letters Patent is:

l. The method of transporting a finely comminuted solid comprising, aerating the finely comminuted solid, pumping the aerated comminuted solid by means of a pump into one end of a collapsible hose having flexibility such that the hose will collapse at least 50% but not more than 95% under a differential pressure of substantially atmospheric pressure, and simultaneously therewith applying suction to the other end of the hose by a pump secured thereto and operated at a volumetric rate in excess of that at which the aerated comminuted solid is pumped into the hose.

2. The method of transporting aerated finely comminuted solid comprising, pumping the aerated comminuted solid by means of a pump into one end of a collapsible hose having a flexibility such that the hose will collapse at least 50% but not more than 90% under a differential pressure of substantially atmospheric pressure, and simultaneously therewith applying suction to the other end of the hose by a pump secured thereto and operated at a volumetric rate in excess of that at which the aerated comminuted solid is pumped into the hose.

No references cited.

Claims (1)

1. THE METHOD OF TRANSPORTING A FINELY COMMINUTED SOLID COMPRISING, AERATING THE FINELY COMMINUTED SOLID, PUMPING THE AERATED COMMINUTED SOLID BY MEANS OF A PUMP INTO ONE END OF A COLLAPSIBLE HOSE HAVING FLEXIBILITY SUCH THAT THE HOSE WILL COLLAPSE AT LEAST 50% BUT NOT MORE THAN 95% UNDER A DIFFERNTIAL PRSSURE OF SUBSTANTIALLY ATMOSPHERIC PRESSURE, AND SIMULTANEOUSLY THEREWITH APPLYING SUCTION TO THE OTHER END OF THE HOSE BY A PUMP SECURED THERETO AND OPERATED AT A VOLUMETRIC RATE IN EXCESS OF THAT AT WHICH THE AERTED COMMINUTED SOLID IS PUMPED INTO THE HOSE.

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