Patent Application
20070283715
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.
Reference is made to the attached drawings in which
The drawings are not drawn to scale. Like numerals in different drawings refer to similar elements.
With reference to
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
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
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.
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.
