US3125423A - Vapor extracting - Google Patents

Description

MarCh 17, 1954 J. s. SHAPLAND ETAL 3,125,423

GRANULAR MATERIAL TANK HAVING AN INTERNAL VAPOR EXTRACTING MEANS March 17, 1964. s. sHAPLAND ETAL 3,125,423

4GRANULAR MATERIAL -TANK HAVING AN INTERNAL VAPOR EXTRACTING MEANS Filed Aug. 28, 1961 2 Sheets-Sheet 2 NVENTORS. ew/fr J 41.0540

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frica/fx United States Patent G 3,125,423 GRANULAR MATERHAL TANK HAVING AN INTERNAL VAPOR EXTRACTING MEANS John S. Shapland and Erwin J. Goldfarb, Champaign, Ill.,

assignors to Koehring Company, Milwaukee, Wis., a

corporation of Wisconsin Filed Aug. 28, 1961, Ser. No. 134,270 4 Claims. (Cl. 341-92) The present invention relates generally Ito means for extracting vapors or the like from tanks containing granular material. More particularly, the invention relates to an improved vapor removing duct arrangement which is located within the tank.

'Ilhe invention can be used with a variety of granular materials, such as grains, chemicals, or aggregates, and for removing different vapors and the like from these materials. For example, the invention can be used tor removing solvents from granular chemical material, but it has found particular utility in removing air and water vapor vfrom aggregates for the purpose of cooling the latter.

Therefore, while the invention will be shown and described as used in connection with apparatusfor coo-ling the aggregate to be used for manufacturing concrete, it is not intended to limit the scope of the invention to such use.

It is generally known in this art to provide a granular material tank which is ysealalale when filled so that water vapor can be extracted from the tank by suction. When sucient suction is created in the tank to remove the `waiter vapor and consequently lower the temperature of the granular material, the tank is opened to restore atmospheric pressure, and the material is removed at a lower temperature.

rMany off these prior art devices utilize a cooling duct is located on the outside of the tank, which duct is in communication with the interior of the tank and subjected to a suction to thereby draw off the vapor from the tank. While these prior art devices have proved to be satisfactory in some respects, they did have certain shortcomings and disadvantages. For example, by using an externally located duct, a relatively tight, strong, and rigid duct was necessary. Furthermore, in these prior devices, the number and location of the communicating passages between the duct and tank were limited and did not provide entirely complete and even circulation and communication off the vapor between the tank `and the exhaust duet. As 'a result, these prior art tanks were not only costly to manufacture but ywere not eoient in operation.

Accordingly, the present invention provides a scalable tank for granular material which has an internal vapor extracting duct which can be subjected to suction and the vapors efliciently removed from the tank. The arrangement is such that the duct is not subjected to excessive pressures and can be fabricated from comparatively lighter material. Furthermore, the duct need not be as airtight as would |an externally located duct, which results in additional economy of manufacture. In addition, more and even distribution of communicating passages between the duct and tank are possible with the improved duct arrangement, which results in easier and more complete yaccess of the 'vapor to fthe duct and consequently' an exceptionally efiicient unit.

Prior art devices have also utilized an internal stone ladder consisting of ya series ot steps over which the material flows during the filling of the tank. These ladders act to momentarily and repeatedly ret-ard the lfall ot the aggregate yto thereby reduce breakage thereof.

A further aspect or -the present invention is to provide an improved tank and internal duct of the above-men- 3,125,423 Patented Mar. 17, 1954 lCe tioned type, in which the duct is combined with the stone ladder so that some of the access openings between the duct and fthe tank are located immediately under and shielded by the steps of the ladder. Thus, extraction of the vapor is thereby accomplished at many levels the ytank and more generally in the central area thereof than was heretofore possible. Not only is more complete, rapid, and even extraction of vapor possible, but substantial economy in manutacture is also effected. The individual steps of the stone ladder provide natural pockets or voids within the filled tank, and with which voids the passages in the duct are in communication. The steps act to shield the passages and thereby preventl aggregate or other material ffrom spilling into the duct.

By combining the cooling duct and stone ladder within the tank, a much larger surface of the granular material is exposed to enhance the flow of vapor from the material into the duct.

In addition, by placing the duct inside the sealed tank, the pressure on the inside and outside of the duct is more nearly equal. As a result, the duct construction need not be as heavy or tight as an external duct, and leakage in the duet is not as critical and does not appreciably decrease the operating efficiency orf the unit.

These and 'other objects and advantages of the present invention will appear hereinafter as this disclosure progresses, reference being had to the accompanying drawings, in which:

FIGURE l is a vertical, cross-sec1tional view taken through a granular material tank made in accordance with the present invention, certain parts being shown as broken away for clarity in the drawing;

FIGURE 2 is a lfragmentary, elevational v-iew, in seoti-on, taken along the line 2 2 in FIGURE l, certain parts being broken away for clarity, and

FIGURE 3 is a iragmentary, perspective view of a portion of the device shown in FIGURES l and 2, certain parts being broken away, the view being taken generally from the inside of the tank and looking outwardly thereof.

'Ihe invention finds particular utility in cooling aggregate `to be used in making concrete and the aggregate tanks used for this purpose are of considerable height and size. The capacities of these tanks must be enormous when used on huge projects such as dams and the like. The ingredients used in making the concrete, such as the sand, water, land aggregate are individually cooled prior to their being mixed, so that the heat generated by the curing concrete after the pour not cause weakening -or cracking of the structure.

The present invention finds particular utility in cooling the aggregate by removing Water vapor from the aggregate immediately before it is mixed with the other ingredients. Vaporization of the Water extracts heat from the aggregate, and this must be carried out continuously and for considerablev periods of time during the pour. When it is apprecated that the capacity of some of these concrete batch plants may be `several hundred cubic yards per hour for a continuous operation and result in concrete out of the mixers at a temperature less than 50 F. while utilizing aggregates with a normal temperature of Sil- F., it will be seen that a dependable and ecient aggregate cooling tank is essential.

Referring in greater detail to the drawings, a large cylindrical tank T having frusto conical-shaped top and bottom portions 3 and 4, respectively, is securely mounted on the `ground GR by means of suitable supports 5, and has a top opening 16 through which the tank is loaded with granular material, such as aggregate. At the lower end of the tank an aggregate discharge opening 7 is provided for withdrawing the aggregate, all in accordance with well-known practice.

Vacuum gates S and 9, respectively, can be placed over the top and bottom openings 6 and 7 in order to seal the entire tank when a vacuum is being drawn in the tank to remove vapor. Resilient gaskets such a-s 8a may be provided for these gates, and the gates can be secured in place in any suitable manner, such as by quick acting latches, or by bolt means 8b, or air ram 9a. Thus, when the gates are secured in place, the entire tank can be subjected to sub-atmospheric pressure, as will appear.

Any one of several means may `be provided for creating a vacuum in the tank and withdrawing air and water vapor therefrom. As this vacuum means per se forms no part of the present invention, and itself is well known in this art, it will not be shown or described other than to say `a steam ejector commonly called a primer is used to rst evacuate air from the tank so that the vacuum is pulled down, for example to approximately 4() millimeters of mercury, absolute pressure. The air and steam required to operate the primer are discharged into a hot well at approximately atmospheric pressure. After most of the air has been reduced by the primer, a larger steam ejector called a booster is cut in to lfurther reduce the vacuum in the tank to approximately 5 millimeters of mercury, absolute pressure. Heat is thereby carried out by the exhaust vapor in the form of latent heat of vaporization. The booster discharges into a barometric condenser which condenses the vapor.

In any event, regardless of the number of stages or specific means used to create sub-atmospheric pressure in the tank, this vacuum is drawn out through an exhaust conduit in the form of a header E which may be in communication with an exhaust duct D (to be described later) at any suitable location. In the drawing chosen for illustrative purposes only, this header is shown adjacent the lower end of the tank and has a gate G operated by a double-acting air ram R. tlf desired a separate smaller header may be connected to the duct D, at any suitable location, for exhausting `air by means of the primer prior to exhausting water vapor through header E.

The gate G is closed while the tank is being filled with or emptied of aggregate. When the aggregate is to be cooled, the vacuum gates `8 and 9 are sealed and gate G is opened to place the duct under sub-atmospheric pressure.

The wall of the cylindrical tank is reinforced by a series of channel iron rings 10 which are welded at vertically spaced locations to the inside of the wall. It will be noted that these channel rings have their open sides facing downwardly.

A stone ladder L is rigidly secured within the tank and is in vertical alignment with the top inlet opening 6 and bottom discharge opening 7. This vertically disposed :ladder is located centrally in the tank and can be fabricated in any one of several different ways. In the example shown for purposes of illustrating the invention, four vertically positioned angle irons `12, 13, 14, and form the corners of the ladder and have a series of horizontally disposed steps 16 welded thereto in vertically spaced relationship to one another. Each step has a back plate 17 and a side plate 18 welded thereto. These side plates act as gussets and are connected to one another by the short pieces of angle iron bars 19 welded therebetween.

The steps alternately extend only part way across the width of the ladder in one direction as shown in FIG- URES 2 and 3, in order that the material passes over each as it falls through the ladder. Thus, each step acts to retard the downward ow of aggregate to prevent excessive breakage thereof, in the well-known manner.

One side of the ladder is closed by a wall 20 which extends from its curved upper edge 21 complementing the curve of the fmsto cone shaped top 3, downwardly to its lowermost edge located adjacent the tank outlet opening 7. This wall is secured to the vertical angles 12 and 4 15, as by welding for example, and as well as enclosing and forming one side of the ladder, this wall performs another function, as Iwill presently be described.

A vertically disposed duct D is located inside the tank and adjacent the stone ladder. The vertical wall 20 of the ladder also acts as one Wall of the duct and has a series of openings 24 therethrough, each opening being located directly beneath a step 16. These openings are formed in this common wall by the tabs 25 which are partially punched out of the wall and extend into the duct at an incline. The other sides of the duct are formed .by an outer wall 26, and the two side walls 27 and 23, all suitably welded together, and the side 26 also being welded to the channel rings 10. Pairs of horizontal cross beams 30 and 31 extend along opposite sides of the combined duct and ladder and are welded thereto and to the rings 10 to thereby secure the duct and ladder within the tank.

As the aggregate falls through the ladder, it is in effeet lowered step by step until it reaches the level of the aggregate which has settled in the tank. The falling aggregate then ows outwardly through the three sides of the ladder which are not blocked off by the duct. A void is formed directly beneath each step due to the angle of repose formed by the aggregate, and the steps thereby act to shield their respective openings 24 located directly beneath the steps. In this manner, the aggregate is prevented from entering the duct, and a series of vertically spaced openings are provided in the tank along its entire height and at a location which is generally in the central portion of the tank.

In addition to the inlet openings 24 formed in the common wall for the ladder and exhaust duct, additional openings 34 are formed along the height of the outer wall 26 of the duct by the tabs 35 pressed inwardly therefrom. More specifically, an opening 34 is provided immediately beneath each of the channel rings 10 and is in communication with the annular void or passage 36 formed by the angle of repose of the aggregate directly beneath the ring. With this arrangeemnt, the channel rings perform the dual function of reinforcing the tank and providing a series of vertically spaced, annular passages in the aggregate which are placed in communication with the exhaust duct. Thus, additional surface area is provided for drawing vacuum at each of the channel rings.

Air and water vapor also enter the duct through its pen top end 38 formed by the top portion 37 of the uct.

The bottom end of the duct 22 is also open for permitting any aggregate which inadvertently enters the duct to fall by gravity from the tank when the latter is emptied. The open bottom of the duct also provides additional area which is exposed to the suction effect of the duct.

As hereinbefore stated, an exceptionally large and well distributed area of aggregate and the interior of the tank are subjected to suction by the duct. As a result, the velocity at any point within the duct is not excessive7 and the amount of material carried in the flow of air and vapor is correspondingly lower. The evenly distributed vacuum effect results in more uniform temperature of the vaggregate as well as a more eflicient unit in general.

By placing the exhaust duct within the tank itself, lighter and less tight construction of the duct is possible because leakage of the duct is not critical inasmuch as the entire tank may be subjected to sub-atmosperic pressure, and the duct need not be able to withstand atmospheric pressure on its outside as the vacuum is being drawn off.

By providing an internally located exhaust duct and one combined with a stone ladder, a particularly eicient vacuum vessel has been provided economically for drawing oif a relatively high vacuum from a sealed tank for the purpose of extracting water vapor or the like.

Various modes of carrying out the invention are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.

We claim:

1. Apparatus for conditioning granular material comprising, a tank adapted to contain a quantity of granular material and having an inlet opening adjacent its upper end and an outlet opening adjacent its lower end for gravitation of said material therethrough, said tank being scalable so as to support a vacuum therein, a series of vertically spaced reinforcing rings secured around the inside of said tank, a generally vertically disposed exhaust duct located wholly within said tank, at least one side of said duct being secured to said rings, a series of vertically spaced openings in said duct, one directly beneath each of said rings for placing the duct in vapor receiving communication with said tank, and an exhaust conduit in communication with said duct for extracting vapor from said duct and tank by vacuum.

2. Apparatus for conditioning granular material comprising, a tank adapted to contain a quantity of granular material, said tank being scalable so as to support a vacuum therein, a stone ladder located generally centrally in said tank and over which said material gravitates, one side of said ladder being formed by a wall having openings therethrough, a series of vertically spaced reinforcing rings secured to the inside of said tank, a generally vertically disposed exhaust duct located in said tank and having one of its sides formed by said wall and also having another Wall adjacent and secured to said rings, said another wall having openings directly under said rings whereby said openings in said walls place the duct in vapor receiving communication with said tank, and an exhaust conduit in communication With said duct for extracting vapor from said duct and tank by vacuum.

3. Apparatus for conditioning granular material comprising, a tank adapted to contain a quantity of granular' material and having an inlet opening adjacent its upper end and an outlet opening adjacent its lower end for gravitation of said material therethrough, said tank being sealable so as to support a vacuum therein, a stone ladder located generally centrally in said tank and including a series of vertically spaced steps over which said material passes, one side of said ladder being formed by a wall having openings therethrough and directly under at least some of said steps whereby said steps act as a shield for their respective openings to prevent material from passinU therethrough, a series of vertically spaced and horizontally disposed rings secured around the inside of said tank and extending inwardly therefrom, a generally vertically disposed exhaust duct located in said tank and having one of its sides formed by said wall, said duct having another wall adjacent said rings, said another wall having openings under said rings whereby said openings place the duct in vapor receiving communication with said tank, and an exhaust conduit extending outside of said tank and in communication with said duct for extracting vapor from said duct and tank by vacuum.

4. Apparatus for conditioning granular material comprising, a tank adapted to contain a quantity of granular material and having an inlet opening adjacent its upper end and an outlet opening adjacent its lower end, said tank being scalable so as to support a vacuum therein, a vertically disposed stone ladder in said tank through which material entering the tank passes, said stone ladder being substantially open on all except one side for passage of said material into the tank and including a series of vertically spaced steps over which said material passes before reaching the level of material deposited in the tank, said one side of said ladder being formed by a wall having a plurality of openings therethrough, a generally vertically disposed exhaust duct wholly within said tank and having one of its sides also formed by said wall, whereby said openings place the duct in vapor receiving communication with said tank, and an exhaust conduit in communication with said duct for extracting vapor from said duct and tank by vacuum.

References Cited in the le of this patent UNITED STATES PATENTS 633,221 Sorlle et al. Sept. 19, 1899 698,129 Niese Apr. 22, 1902 2,073,553 Dienst Mar. 9, 1937 FOREIGN PATENTS 333,943 Germany Mar. 5, 1921

Claims (1)

1. 3. APPARATUS FOR CONDITIONING GRANULAR MATERIAL COMPRISING, A TANK ADAPTED TO CONTAIN A QUANTITY OF GRANULAR MATERIAL AND HAVING AN INLET OPENING ADJACENT ITS UPPER END AND AN OUTLET OPENING ADJACENT ITS LOWER END FOR GRAVITATION OF SAID MATERIAL THERETHROUGH, SAID TANK BEING SEALABLE SO AS TO SUPPORT A VACUUM THEREIN, A STONE LADDER LOCATED GENERALLY CENTRALLY IN SAID TANK AND INCLUDING A SERIES F VERTICALLY SPACED STEPS OVER WHICH SAID MATERIAL PASSES,ONE SIDE OF SAID LADDER BEING FORMED BY A WALL HAVING OPENINGS THERETHROUGH AND DIRECTLY UNDER AT LEAST SOME OF SAID STEPS WHEREBYU SAID STEPS ACT AS A SHIELD FOR THEIR RESPECTIVE OPENINGS TO PREVENT MATERIAL FROM PASSING THERETHROUGH, A SERIES OF VERTICALLY SPACED AND HORIZONTALLY DISPOSED RINGS SECURED AROUND THE INSIDE OF SAID TANK AND EXTENDING INWARDLY THEREFROM, A GENERALLY VER-

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