Powder cooler start-up aeration system

Abstract

A method of starting a vertically situated cylindrical cooler for powered material such as cement within which material to be cooled moves upward through the cooler by being propelled by rotatable spiral flights. The method is advantageously used when the cooler, because of a crash stop, is prevented from starting normally because of an excess of packed material located at its bottom, thus preventing the spiral flights from rotating. According to the method of the invention, a compressed gas is introduced into the bottom portion of the cooler in a quantity sufficient to aerate the packed material. Once the material is sufficiently aerated the spiral flights are able to be rotated, thereby propelling the material upward through the cooler.

Description

BACKGROUND OF THE INVENTION

Powder coolers are commonly utilized in the production of cement.

One type of cement cooler is a stationary, vertically upright essentially hollow cylindrical cooler. Such a cooler is typically a steel tank that cools on an indirect cooling basis. The cooler can be utilized to cool cement powder after it comes from the grinding process, such as from a ball mill, but can also be used for cooling other types of pulverized material such as, for example, lime, gypsum, chemicals, food products and various ores.

In such cylindrical coolers material to be cooled is introduced into the interior of the cooler near the bottom of the cooler and is moved upward-through the interior of the cooler to a material outlet located near the top of the cooler by internal rotating spiral, i.e. screw, flights mounted on a framework attached to an internal vertical steel rotating shaft. The centrifugal action of the rotating flights also serves to thrust the material towards the interior wall of the cooler.

The material is cooled in indirect fashion by coming into contact with the water-cooled internal surface of the cylinder, with the cooling water being applied to the exterior wall of the cylinder.

At times it is necessary, during operation of the cement plant, to stop the cooler, usually for reasons that are independent from the operation of the cooler.

During such periods of shutdown, the powder falls to the bottom of the cooler forming a pile. At times, particularly if an hour or more has passed before attempts are made to restart the cooler, the material may become packed and thereby “plug up” or “freeze” the cooler, thus preventing or hindering the rotor blades, and consequently the spiral flights, from rotating. Typically the cooler has to be partially or completely emptied before the rotor can spin a procedure that is inconvenient and time consuming.

It would be desirable to have a system to start-up a vertically situated material-containing cooler from a crash stop that does not necessitate emptying the cooler of its contents. The present invention provides for such a system, in which the material that is at the bottom of the cooler is fluidized by a compressed gas, typically an ambient air delivery system, thus allowing the rotor to turn.

DESCRIPTION OF THE DRAWINGS

Reference is made to the attached drawings in which

FIG. 1 is a vertical perspective, partially cut away, of a cooler that can be modified by the system of the present invention.

FIG. 2 is a drawing of a top perspective of the system of present invention.

FIG. 3 is a drawing of Section A-Al of FIG. 2 showing a portion of a gas distribution system of the present invention.

FIGS. 4 and 5 are details of two embodiments of a nozzle assembly of the present invention.

FIG. 6 is a schematic of the present system.

The drawings are not drawn to scale. Like numerals in different drawings refer to similar elements.

DESCRIPTION OF THE INVENTION

With reference to FIG. 1, there is depicted a cooler 10 to which the present system can be advantageously adopted. Material to be cooled enters cooler 10 through inlet 1. Rotating screw flights 2 driven by a motor (not shown) convey the material upward to material outlet 3 while flinging the material outwards, where it comes in contact with the inner surface of the cooler, which is cooled by water in conduits (not shown) which are distributed evenly over the outer surface of the cooler. Cooling water flows from water inlet 4 through the water conduits to water outlet 5 by gravity.

The cooler stands on supports 6. The air distribution system 7 of the present invention will be introduced adjacent to the bottom perimeter of the cooler, and will direct compressed gas up through the bottom floor 8 of the cooler. The gas may be cleaned and dried compressed plant air.

With reference to FIG. 2, displayed is the piping manifold which will be placed underneath cement cooler.

Clean and dry compressed gas enters the system through main gas line 11, and is distributed to secondary gas lines 12. Gas is then distributed to individual lines 13 and eventually into aeration nozzles 14, which are distributed by being more or less evenly spaced around the bottom perimeter of the cooler, in an amount sufficient to aerate and essentially fluidize the material that is located at the bottom-of the cooler, thus allowing the cooler derive to be started by normal methods. Shown in relief are supports 6 for the cooler.

The embodiment of FIG. 2 has a total of 32 nozzles 14, although more or less may be employed, depending on variables including the size of the cooler and the composition of the material in the cooler.

FIG. 3 shows a portion of the air distribution system of the present invention. As shown, the main air line 11 is placed underneath the bottom 21 of the cooler. Main air line 11 is connected to secondary air lines 12, which are connected to nozzle systems 20, which are shown in greater detail in FIG. 4 and 5. Each nozzle 14 is in intimate contact with the inner bottom floor 8 of the cooler on which cement powder will rest when the cooler is not operated. Obviously, there are holes (not shown) provided in inner bottom floor 8 for each nozzle 14.

FIGS. 4 and 5 show substantially identical individual nozzle systems 40 and 50, with the only difference in such systems being that the systems depicted in FIG. 4 are adapted for use in areas in-which there are space limitations, and specifically when the nozzles are to be placed directly above a support 6.

Each nozzle system 40 and 50 has individual air delivery lines 13 which bring compressed gas into regulator 41, which serves to bring the pressure of the compressed gas down to a desired level. Typically regulator 41 will bring the pressure of the compressed gas from the supply pressure to the required pressure and subsequent flow. The reduced pressure air is directed through flow valve 42,-which can shut off the air flow entirely. These valves can be operated manually or automatically and may be eliminated if not needed

Nozzle 14 may be a vibrating type nozzle which serves to prevent material from backflowing into the system. As depicted, nozzle 14 is situated underneath a hole 43 in inner floor 8 of the cooler. These nozzles are located in a distinct compartment 45 through the use of partition walls 46, thus keeping any material self contained within the compartment 45. Alternatively, nozzle 14 can be located within a round pipe welded to floor 8, or directly on top of floor 8, or in any other arrangement or location which would accomplish the same purpose.

FIG. 6 depicts schematic main gas line 11 which has shut off valve 9, which may allow activation of the system from a remote or a local assembly. Each-nozzle assembly 20 typically has a nozzle 14 and flow regulator 41, which allows for precise airflow to the aeration units.

While there are shown and described present preferred embodiments of the invention, it is to be understood that the invention is not limited thereof, but may be otherwise variously embodied and practiced within the scope of the following claims.

Claims

1. A method of starting a vertically situated cylindrical powder cooler having a bottom portion near which powdered material to be cooled enters the cooler and an upper portion near which the cooled material exits the cooler, said cooler having interior rotatable spiral flights that when in rotation serve to move material to be cooled upward through the cooler, wherein the rotation of said flights is prevented or hindered by an accumulation of material located at the bottom of the cooler, said method comprising introducing a quantity of gas into the bottom of the cooler sufficient to aerate the material located at the bottom of the cooler and thereby allowing the flights to be rotated.

2. The method of claim 1 wherein the powdered material to be cooled is cement.

3. The method of claim 1 wherein the powdered material to be cooled is lime.

4. The method of claim 1 wherein the powdered material to be cooled is gypsum.

5. The method of claim 1 wherein the gas is introduced into the cooler through a plurality of nozzles which are distributed around the bottom perimeter of the cooler.

6. The method of claim 5 wherein the plurality of nozzles are evenly spaced around the bottom perimeter of the cooler

7. The method of claim 6 wherein each nozzle is in contact with the inner bottom floor of the cooler.

8. The method of claim 6 wherein at least one of said plurality of nozzles is a vibrating type nozzle which serves to prevent the backflow of material into the nozzle.

9. A powder cooler, said cooler comprising

(a) a vertically situated cylindrical body having a bottom portion near which there is a material entrance through which powdered material to be cooled enters the interior of the cooler and an upper portion near which there is a material exit through which cooled material exits the cooler,

(b) a plurality of interior rotatable spiral flights that when in rotation serve to move material upward through the cooler;

(c) means to rotate the spiral flights; and

(d) means to introduce gas into the bottom portion of the cooler in an amount sufficient to aerate material located at the bottom of the cooler.

10. The cooler of claim 9 wherein the gas is introduced into the-cooler through a plurality of nozzles which are distributed around the bottom perimeter of the cooler.

11. The cooler of claim 10 wherein the plurality of nozzles are evenly spaced around the bottom perimeter of the cooler

12. The cooler of claim 11 wherein each nozzle is in contact with the inner bottom floor of the cooler.

13. The cooler of claim 10 wherein at least one of said plurality of nozzles is a vibrating type nozzle which serves to prevent the backflow of material into the nozzle.