Patent Publication Number: US-2013251545-A1

Title: Modular air discharge system

Description:
BACKGROUND 
     Throughout a wide range of industries and manufacturing processes, air knives and air nozzle manifolds have been used for decades to deliver pressurized air, which is generated by an air mover, i.e., a fan, blower or compressor, to blow against the surface of stationary or moving objects to remove liquid or debris from or to cool or to heat the surface of those objects. See for example U.S. Pat. Nos. 6,898,867 and 6,990,751 for which I am an inventor. The most common applications for air knives or air nozzle manifolds is when products, during certain processes of conveyorized manufacturing, must be cleaned, cooled, lubricated or warmed with water or other liquid which then must blown off using air knives or air nozzle manifolds with their high velocity non-contact air streams needed to ready the products for their next manufacturing process. Typically a fan or blower is the air mover when the air knife or nozzle pressures are less than 10 psig. A compressor is used as the air mover when the required air knife or nozzle pressures are between 10 psig and 100 psig. 
     An air knife consists of a manifold or plenum from which an elongated narrow air slot, either continuous or segmented, has pressurized air exiting from it in a laminar flow pattern across the length of the air slot. Air knives are generally best suited for operation within close proximity of the part being blown off and where any interruption in the continuous air flow may be detrimental to the blow off effect 
     An air nozzle manifold consists of a manifold or plenum from which multiple air nozzles, with round or elongated openings, are placed at various intervals along the length of the manifold. The air nozzle manifold does not provide a continuous laminar air flow along its length as does an air knife. Each orifice of the nozzles delivers a much larger air flow in a concentrated area than does an air knife and is therefore capable of projecting high velocity air streams from each nozzle for distances which are three to four times greater than an air knife for the same relative electric power to the air mover. 
     Previous designs of air nozzle manifolds have an air plenum or header comprised of either a round, square or formed metal or plastic shape, to receive the air from the air mover via a pipe, duct or hose. The air header also serves as the rigid mounting point for all of the externally mounted air nozzles protruding from the body of the air header. Attachment of the air nozzles to the header is either by means of threaded ports, hose barbs or weld points. Most of the finished air nozzle manifold designs are single purpose built with little or no adjustment possible in the diameter, center distance or angle of the nozzles. 
     In some designs, flexible hose connection between the air header and the nozzles has been used to facilitate nozzle adjustments. However, these nozzles with flex hose increase the overall size of the air nozzle manifold assembly. Also the flex hoses reduce effectiveness due to air friction losses, and it is difficult to retain the air nozzles in a fixed position for consistent air blow off results. 
     Therefore there is a need to have more flexibility in the operation of air nozzle manifolds to adapt for changing applications of the manifold than is possible with current designs. 
     SUMMARY 
     The present invention provides a system that satisfies this need. The system includes an air discharge apparatus that comprises an elongated air distribution enclosure such as a plenum having an air supply inlet and an elongated air discharge slot. At least one removeable insert is in the discharge slot and at least one of the inserts has at least one discharge opening for discharging air from the enclosure where air can pass through the slot substantially only through discharge openings. The discharge openings have an inlet and an outlet. Because the inserts are removable, the system is modular, being easily adapted for different manufacturing conditions. 
     Spacing between the discharge openings can be controlled by using spacer inserts that have no discharge openings. A single insert can have multiple discharge openings. Typically the direction of discharge of the discharge openings is not adjustable to change the direction of discharges. Thus typically it is necessary to replace an insert to achieve a change in direction of air flow. A single insert can have multiple openings, where some of the openings discharge at different angles. Also a first insert can have an opening discharging at a first angle and a second insert can have an opening discharging at a second angle, the first and second angles being different. 
     Preferably the enclosure has exterior walls that taper towards each other proximate to the discharge slot. The inserts preferably are sized to fit between the exterior walls proximate to the discharge slot without being able to fit through the discharge slot. The inserts can be held in place by one or more releasable clamps or screws. 
     Preferably the discharge openings are tapered such as by uniformly decreasing the cross sectional area from the inlet to the outlet. 
     In use of the apparatus, at least one insert is removably placed in the discharge slot, where at least one of the placed inserts has a discharge opening. As needed, one or more of the inserts can be removed and replaced with a different removable insert. 
     Typically the device is used for discharging air that contains no liquid, i.e., typically it is not used for spraying liquids. 
    
    
     
       DRAWINGS 
       These and other features, aspects, and advantages of the present invention will become better understood with reference to the following description, appended claims, and accompanying drawings where: 
         FIG. 1  is a perspective view of an air drying system having features of the present invention being used for drying target pieces; 
         FIG. 2  shows a first air discharge apparatus usable in the system of  FIG. 1  having five different inserts; 
         FIG. 3  is a schematic view of a portion of a second air discharge apparatus having multiple inserts separated by spacers, the apparatus having features of the present invention; 
         FIG. 3A  is a detailed view of region  3 A in  FIG. 3 ; 
         FIG. 4  is a schematic view of a third air discharge apparatus having features of the present invention; 
         FIG. 4A  is a detailed view of region  4 A in  FIG. 4 ; 
         FIG. 5  is an exploded perspective view of the second version of the air discharge apparatus as shown in  FIG. 3 ; 
         FIG. 6  is an exploded perspective view of a fourth version of an air discharge apparatus having features of the present invention; and 
         FIG. 7  is a sectional view of the apparatus of  FIG. 5  taken along lines  7 - 7  in  FIG. 5  with the inserts in place. 
     
    
    
     DESCRIPTION 
     With regard to  FIG. 1 , target pieces  10  are supported on a support  12  for treatment with air provided by an air discharge apparatus  14  such as an air knife blowing air in a direction such as shown by arrows  16 . Air under pressure is provided to the air discharge apparatus  14  by a fan  18  powered by a motor  20 , the air passing from the fan  18  to the air discharge apparatus  16  through a duct  21 . 
     With regard to  FIGS. 2 and 3 , the air discharge apparatus  14  comprises an enclosure  22  enclosing a plenum  22   a  (as shown in  FIG. 7 ). The enclosure  22  comprises a main body  23  having an external wall  24  and an open end closed by an end cap  25  secured by fastener  26 , an air supply inlet  27  for connection to the duct  21 , and an elongated discharge slot  28  having a longitudinal axis  29 . The enclosure  22  has a tear drop or pear shape as conventionally used for air knife designs. It can be made from any material conventionally used in air knife designs, such as stainless steel, plastics and aluminum. 
     There is at least one removeable insert  30  proximate to and typically located at the discharge slot  28 , where at least one of the inserts  30  has a discharge opening  32 , also referred to as an orifice or nozzle hole. Air can pass through the discharge slot substantially only through the discharge openings  32 . In the version of the invention shown in  FIG. 2 , there are five inserts  30   a,    30   b,    30   c,    30   d  and  30   e,  having  4 ,  3 ,  1 ,  4 , and  3  discharge openings  32 , respectively. Thus different inserts can have a different number of discharge openings. The inserts can be made from any material conventionally used for air knife designs, including stainless steel, aluminum and plastic. 
     As will be demonstrated from other exemplary versions of the invention, the apparatus  14  can have the following variations of inserts:
         1. Only one insert, where that insert has at least one discharge opening.   2. Two or more inserts, where each insert has at least one discharge opening.   3. At least two inserts, where at least one serves as a spacer having no discharge openings.   4. The discharge openings in a single insert, or in different inserts, discharge air in the same direction, or in different directions. For example, discharge opening  32 ′ can discharge air towards the left in  FIG. 2 , discharge opening  32 ″ can discharge air directly straight out, discharge orifice  32 ′″ can discharge air towards the right, discharge opening  32 ″″ can discharge air upwardly, and discharge opening  32 ′″″ can discharge air downwardly. The openings  32  can be oriented to discharge in any direction, such as upwardly and toward the right in  FIG. 2 . Thus discharge openings  32  can discharge air at the first angle relative to the longitudinal axis  29  where different discharge openings discharge at different angles relative to the longitudinal axis  29 .       

     Optionally there can be a one or more reinforcing bars on the exterior wall. 
     With reference to  FIGS. 3 and 5 , there is shown a version of the present invention where the air distribution apparatus  14  is provided with ten inserts, seven inserts  42  having a single discharge opening  44 , and six spacer inserts  46  having no discharge opening. There is a spacer insert  46  between each pair of discharge inserts  42 . 
     As best shown in  FIGS. 3A ,  6  and  7 , the external wall  24  can be generally tapered toward the discharge slot  28 , and the inserts can have a corresponding shape. The inserts are sized to fit between the exterior walls proximate to the discharge slot  28  without being able to fit through the discharge slot  28 . 
     It is desirable that the discharge openings  32  taper, having an inlet end  48  and a discharge end  50 , the cross-sectional area of the inlet end  48  being greater than the cross-sectional area of the outlet end  50  so that the velocity of air passing through the discharge opening increases from the inlet end  48  to the outlet end  50 . Preferably the inlet end  48  of each discharge opening is about 25% larger in cross sectional areas than the air exit end  50  of each discharge opening, thereby allowing the air to increase in velocity as it approaches the nozzle exit. The exit velocity of air at outlet  50  is about four times greater than the inlet velocity from the air plenum. Most preferably the discharge opening uniformly increases in cross-sectional area from the inlet end  48  to the outlet end  50 . This allows the air being discharged to make a gradual transition from the plenum towards the air outlet  50 . 
     Preferably the angle of each nozzle hole  30  through the insert should be between 15 and 20 degrees to achieve maximum efficiency. Thus the sides  61  of the nozzle hole taper inwardly relative to the centerline by about 15 to about 20 degrees toward the outlet end  50 . This helps produce low turbulence during air velocity acceleration and deliver a narrow exit air flow pattern to create high impact air velocities at the parts requiring the air. 
     The pressure of air entering the plenum can be from 0.1 psig to about 100 psig, depending on the pressure rating of the plenum. It is desirable that the apparatus  14  be designed with materials of construction that can withstand twice the maximum expected air pressure. 
     Each insert can be supplied with varying nozzle diameters and angles. The spacer inserts allow for the user to flexibly select a wide variety of nozzle sizes, nozzle angles and nozzle patterns. With reference to  FIG. 4 , discharge openings  52   a,    52   b  and  52   c  of insert  54   a  discharge at the same first angle generally to the left in  FIG. 4 , the single discharge opening  52   d  of insert  54   b  discharges air straight downwardly, and discharge openings  52   e,    52   f,  and  52   g  of insert  54   c  discharge air generally towards the right in  FIG. 4 . 
       FIG. 6  shows a discharge apparatus  14  having a single insert  62  having ten discharge openings  64 . 
       FIG. 7  shows how the inserts are held in place in a plenum. This is accomplished with a plurality of retaining bars, each having one end with an enlarged head  72   a,  engageable with an Allen wrench, and a threaded end  73 . Each retaining bar extends through openings  24   a  in the walls  24  of the enclosure and is held in place with a nut  74  on the threaded end  73  of the retaining bar  72 , also referred to as a retention clamp  72 . The bars  72  squeeze the opposing walls of the enclosure together to hold the inserts within the plenum, thus preventing air leaks between the plenum and the inserts. Merely by loosening the nut  74 , and removing the retaining bar  72 , the inserts can be replaced with different inserts depending upon the requirements of the application for the apparatus. Accordingly, by the term “removeable” with regard to the inserts there is meant an insert that can be moved from, and thus replaced, in the discharge slot, merely by simple mechanical means. This is to distinguish from conventional air discharge openings or nozzle that are formed integral with the air distribution enclosure, or welded in place, or held in place by an adhesive or solder, or rivets, or the like. Thus a removable insert can be taken away from the enclosure without damaging the enclosure. This is also different from threaded air nozzles which are not in the discharge slot. 
     The number of bars  72  depends on the length and width of the plenum as well as the air pressure rating itself. Typically there is one retaining bar  72  for each 4″ of air plenum length and retaining bars  72  in parallel across the entire length of the plenum. 
     In use of the distribution apparatus  14 , when it is desired to change the air distribution, one ore more of the existing inserts can be replaced, and with a different removable insert. In some instances, all of the placed inserts can be replaced with different removeable inserts. 
     There are significant advantages associated with the present invention. It is smaller than prior art distribution apparatus when comparing the same number of air nozzles as long as the air volume rating is at least 50% as much as the air plenum with nozzles in the present invention. It utilizes modular components for quick and easy assembly of each manifold with a wide variety of nozzle sizes, nozzle angles, nozzle center distances, and number of nozzles per manifold. Due to the compact size and high air efficiency, the modular assembly is very effective in operation. 
     Although the present invention is has been described in considerable detail with reference to certain preferred versions thereof, other versions are possible. Therefore the claims should not be limited to the description of the preferred versions contained herein. 
     The reader&#39;s attention is directed to all papers and documents which are filed concurrently with this specification and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference. 
     All the features disclosed in this specification (Including any accompanying claims, abstract, and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features. 
     Any element in a claim that does not explicitly state “means for” performing a specified function, or “step for” performing a specific function, is not to be interpreted as a “means” or “step” clause as specified in 35 U.S.C. §112, ¶916. In particular, the use of “step of” in the claim herein is not intended to invoke the provisions of 35 U.S.C. §112, ¶916.