Patent Publication Number: US-2006000297-A1

Title: Ambient particulate sampler inlet assembly

Description:
FIELD OF THE INVENTION  
      This invention relates to an ambient gas particulate sampler.  
     BACKGROUND OF THE INVENTION  
      Ambient particulate samplers are used to measure particles in the air typically to quantify the pollution level at a specific location. A typical ambient particle sampler includes an inlet assembly defined by an inlet upper section and a “bullet” body or lower section housing an impaction chamber. A sample unit is connected to the bullet body lower section portion of the inlet assembly. Ambient air is drawn into the inlet upper section and through a nozzle jet in the inlet upper section by a vacuum pump located in the sample unit.  
      The nozzle jet directs the air to the impaction chamber of the lower section. The air then passes through one or more outlets in the bottom impact plate of the impaction chamber and ultimately to the sample unit.  
      Depending on the particle size of interest and the monitoring plan or set-up, the nozzle jet can be one of a large “TSP” or total suspended particulate nozzle, a “PM 10” or particle measurement 10 (micrometers), a PM 5, or a PM 1 nozzle.  
      Thus, those skilled in the art have long offered inlet assemblies each fitted with a different size nozzle which requires the user to purchase a different inlet assembly for each particle size of interest. Those skilled in the art have also attempted to configure an inlet assembly with multiple different size nozzle jets each fitted in the inlet assembly but without success. Such multiple jet/multiple nozzle inlet assembles have not been fully tested, were complex, and expensive.  
     SUMMARY OF THE INVENTION  
      It is therefore an object of this invention to provide an ambient particulate sampler assembly which can be fitted with different size nozzle jets by the user or manufacturer allowing the user to selectively choose which particulate measuring criteria best suits the user&#39;s requirements.  
      It is a further object of this invention to provide such a sampler assembly which is accurate, tested, and simple in design.  
      It is a further object of this invention to provide such an ambient particulate sampler assembly which is inexpensive to manufacture.  
      The subject invention results from the realization that a reconfigurable ambient particulate sampler is effected by an omnidirectional upper section with an impactor nozzle housing accommodating a single nozzle jet and a set of different size nozzle jets insertable in the impactor nozzle housing allowing the user or manufacturer to selectively choose which particulate measuring criteria best suits the user&#39;s requirements.  
      The subject invention, however, in other embodiments, need not achieve all these objectives and the claims hereof should not be limited to structures or methods capable of achieving these objectives.  
      This invention features an ambient particulate sampler assembly with an upper section including a nozzle entry and an impactor nozzle housing removably accommodating a single nozzle jet, and a lower section removable from the upper section and including an impaction chamber with one or more outlets. A set of different size nozzle jets are provided each separately insertable in the impactor nozzle housing allowing the user to selectively choose a particular measuring criteria.  
      Typically, a sample unit is connected to the lower section and, in the preferred embodiment, the sample unit includes a vacuum source for drawing ambient gas into the upper section at a flow rate of 5 liters per minute or approximately 5 liters per minute. In one example, the upper section includes a top plate baffle spaced from a lower baffle plate. In the same example, the lower section impaction chamber includes three outlets and a water conduit. A water trap is connected to the water conduit. The plurality of nozzle jets may include a TSP nozzle jet, a PM 10 nozzle jet, a PM 5 nozzle jet, and/or a PM 1 nozzle jet.  
      In one embodiment, an ambient particulate sampler inlet in accordance with this invention features an upper section accommodating a single nozzle jet, a lower section removable from the upper section and including an impaction chamber, and a plurality of different size nozzle jets insertable in the upper section. The upper section typically includes a top plate baffle spaced from a lower plate baffle. The lower section impaction chamber typically includes three outlets. In the preferred embodiment, the upper section includes a nozzle entry which receives an impactor nozzle housing including a channel which removably receives one of the nozzle jets.  
      One particular example of an ambient particulate sampler assembly in accordance with this invention includes an upper section including a nozzle entry connected on one end to a baffle plate assembly and connected on the other end to an impactor nozzle housing. A set of different size nozzle jets are insertable one at a time in the impactor nozzle housing. A lower section is removably connected to the impactor nozzle housing and defines an impaction chamber in fluid communication with an exit conduit. A sampler unit is connected to the exit conduit of the lower section and includes a pump for drawing ambient gas into the upper section at a flow rate of 5 liters per minute or approximately 5 liters per minute. In one example, a filter is located between the sampler unit and the exit conduit of the lower section. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      Other objects, features and advantages will occur to those skilled in the art from the following description of a preferred embodiment and the accompanying drawings, in which:  
       FIG. 1  is a schematic three-dimensional view of an example of a complete ambient particulate sampler in accordance with the subject invention;  
       FIG. 2  is a schematic exploded view showing an example of the inlet assembly portion of the sampler shown in  FIG. 1 ;  
       FIG. 3  is a schematic three-dimensional view showing the inlet assembly of  FIG. 2  from a different perspective;  
       FIG. 4  is a schematic cross-sectional view of the upper section of the inlet shown in  FIGS. 2 and 3 ;  
       FIG. 5  is a bottom plan view of the nozzle entry portion of the upper section of the inlet shown in  FIG. 4 ;  
       FIG. 6  is a schematic cross-sectional view taken a long line  6 - 6  of  FIG. 5 ;  
       FIG. 7  is a schematic three-dimensional side view of the impactor nozzle housing shown in  FIGS. 2-3 ;  
       FIG. 8  is a schematic bottom plan view of the impactor nozzle housing shown in  FIG. 7 ;  
       FIG. 9  is a schematic cross-sectional view taken a long line  9 - 9  of  FIG. 8 ;  
       FIG. 10  is a schematic bottom plan view of the lower section of the inlet shown in  FIGS. 2-3 ;  
       FIG. 11  is a schematic cross-sectional view taken a long line  11 - 11  of  FIG. 10 ;  
       FIG. 12  is a schematic bottom plan view of a PM 17 nozzle jet in accordance with the subject invention;  
       FIG. 13  is a schematic cross-sectional view taken a long line  13 - 13  of  FIG. 12 ;  
       FIG. 14  is a schematic bottom plan view of a PM 10 nozzle jet in accordance with the subject invention;  
       FIG. 15  is a schematic cross-sectional view taken a long line  15 - 15  of  FIG. 14 ;  
       FIG. 16  is a schematic bottom plan view of a PM 2.5 nozzle jet in accordance with the subject invention;  
       FIG. 17  is schematic cross-sectional view taken a long line  17 - 17  of  FIG. 16 ;  
       FIG. 18  is a schematic bottom plan view of a PM 1 nozzle jet in accordance with the subject invention; and  
       FIG. 19  is a schematic cross-sectional view taken a long line  19 - 19  of  FIG. 18 . 
    
    
     DISCLOSURE OF THE PREFERRED EMBODIMENT  
      Aside from the preferred embodiment or embodiments disclosed below, this invention is capable of other embodiments and of being practiced or being carried out in various ways. Thus, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of components set forth in the following description or illustrated in the drawings. If only one embodiment is described herein, the claims hereof are not to be limited to that embodiment. Moreover, the claims hereof are not to be read restrictively unless there is clear and convincing evidence manifesting a certain exclusion, restriction, or disclaimer.  
      A complete ambient particulate sampler  10 ,  FIG. 1 , in accordance with the subject invention, includes omnidirectional inlet assembly  12 , filter  16 , and sample unit  18 . Vacuum pump  19  within sample unit  18  draws ambient air into the upper section  20  of inlet  12  preferably at a flow rate of 5 liters per minute, through a nozzle jet therein, to an impaction chamber in lower section  22 , and ultimately to sample unit  18 . Water collected in the impaction chamber of lower section  22  is collected in water trap  14 .  
      In the preferred embodiment shown in  FIGS. 2-3 , upper section  20  includes nozzle entry  30  connected to impactor nozzle housing  32  with a single nozzle receiving channel  68  as shown in  FIG. 9  for accommodating a single nozzle jet  50   d ,  FIGS. 2-3 . Lower section  22 ,  FIG. 3  includes impaction chamber  34  with outlets  36   a ,  36   b , and  36   c  through impact plate  38 . Water conduit  40  provides a pathway for water collected in impaction chamber  34  to be drawn into water trap  14 . Nozzle entry  30  is typically connected to baffle assembly  42  including top plate baffle  44  spaced from lower battle plate  46 .  
      Upper section  20  is removable from lower section  22  by threads  33  and  35 , and a set of different size nozzle jets  50   a ,  50   b ,  50   c , and  50   d  are each insertable in impactor nozzle housing  32 , one at a time, allowing the user or manufacturer to selectively choose a particular particulate measuring criteria according to the user&#39;s requirements.  
      In  FIGS. 2-3 , TSP or total suspended particulate nozzle  50   d  is shown inserted (screwed) into impactor nozzle housing  32 . But, if the user so desires, TSP nozzle jet  50   d  can be removed from impactor nozzle housing  32  and replaced with PM 10 nozzle jet  50   b , PM 2.5 nozzle jet  50   c , or PM 1 nozzle jet  50   a . For example, in  FIG. 11 , PM 2.5 nozzle jet  50   c  is shown in place in impactor nozzle housing  32 . In this way, the particulate sampler inlet assembly of this invention can be fitted with different nozzle jets by the user allowing the user to selectively choose which particulate measuring criteria best suites the user&#39;s requirements.  
       FIG. 4  shows an example of upper section  20  in more detail. Nozzle entry  30  is fastened to upper baffle plate  44  and lower baffle plate  46 , wind deflector  60 , and rain deflector  62  are provided.  FIGS. 5-6  show nozzle entry  30  alone. Proximal end  66  of impactor nozzle housing  32 ,  FIGS. 7-9  is connected to distal end  64  of nozzle entry  30 ,  FIG. 6 . Impactor nozzle housing  32  includes single 0.437″ channel  68  for receiving one nozzle jet of the set of jets  50   a - 50   d ,  FIGS. 2-3 . Flange  70 ,  FIG. 11  of nozzle jet  50   c  properly positions the distal end  72  of nozzle jet  50   c  from impact plate  38  for a flow rate of 5 liters per minute through nozzle entry  30 ,  FIGS. 4-6  and jet  50   c ,  FIG. 11 . This flow rate is lower than the 16.7 liters per minute flow rate of standard prior art sampler systems reducing the power requirements of pump  19 ,  FIG. 1  and allowing the use of system  10  at higher elevations and at remote sites where AC power is not available. Solar power or batteries, for example, may be used to power sample unit  18 .  
       FIGS. 10-11  show in more detail impactor nozzle housing  32  removably connected to lower section  22  including impaction chamber  34  in fluid communication with exit conduit  74  via outlets  36   a - c ,  FIG. 3 . Only exit conduit  36   a  is shown in  FIG. 11 . Exit adapter  76  interconnects exit conduit  74  with filter unit  16 ,  FIG. 1 .  
       FIGS. 12-13  show in more detail an example of aluminum PM 17 or TSP nozzle jet  50   d  with 0.375″ orifice  80   d .  FIGS. 14-15  show in more detail an example of PM 10 nozzle jet  50   b  with 0.263″ orifice  80   b .  FIGS. 16-17  show in more detail an example of PM 2.5 nozzle jet  50   c  with 0.106″ orifice  80   c .  FIGS. 18-19  show in more detail an example of PM 1 nozzle jet  50   a  with two 0.047″ orifices  80   a  spaced 0.168″ apart.  
      The result is an ambient particulate sampler assembly which can be fitted with different size nozzle jets by the user or manufacturer allowing the user to selectively choose which particulate measuring criteria best suits the user&#39;s requirements. The sampler assembly of this invention is accurate, tested, and simple in design, also inexpensive to manufacture. Reconfigurable ambient particulate sampler  10 ,  FIG. 1  is effected by an omnidirectional inlet assembly  12  with an upper section  20  removable from lower section  22  and a set of different size nozzle jets  50   a ,  50   b ,  50   c , and  50   d ,  FIGS. 2-3  insertable in impactor nozzle housing  32  by the user allowing the user to selectively choose which particulate measuring criteria best suits the user&#39;s requirements.  
      Although specific features of the invention are shown in some drawings and not in others, this is for convenience only as each feature may be combined with any or all of the other features in accordance with the invention. The words “including”, “comprising”, “having”, and “with” as used herein are to be interpreted broadly and comprehensively and are not limited to any physical interconnection. Moreover, any embodiments disclosed in the subject application are not to be taken as the only possible embodiments. Other embodiments will occur to those skilled in the art and are within the following claims. For example, other nozzle jets different from or in addition to the nozzle jets described herein may be provided to the user.  
      In addition, any amendment presented during the prosecution of the patent application for this patent is not a disclaimer of any claim element presented in the application as filed: those skilled in the art cannot reasonably be expected to draft a claim that would literally encompass all possible equivalents, many equivalents will be unforeseeable at the time of the amendment and are beyond a fair interpretation of what is to be surrendered (if anything), the rationale underlying the amendment may bear no more than a tangential relation to many equivalents, and/or there are many other reasons the applicant can not be expected to describe certain insubstantial substitutes for any claim element amended.