A collecting device and a method for collection of airborne particles from a flow of air

Abstract

A collecting device ( 200 ) for collecting airborne particles comprises: a first ( 202 ) and second layer ( 220 ) spaced apart for forming a particle collection chamber ( 240 ) therebetween, wherein inlets ( 210 ) extend through the first layer ( 202 ) for transporting a flow of air into the particle collection chamber ( 240 ); wherein ends ( 214 ) of the inlets ( 210 ) face a first surface ( 222 ) of the second layer ( 220 ) for capturing airborne particles by impaction; wherein outlets ( 230 ) extend through the second layer ( 220 ) for transporting the flow of air out of the particle collection chamber ( 240 ); wherein the inlets ( 210 ) and outlets ( 230 ) are staggered such that the center axes of the inlets ( 210 ) and outlets ( 230 ) are displaced from each other; wherein the flow of air experiences a pressure drop lower than 3 kPa at a flow rate of 0.5 liters per second, when the flow of air passes the collecting device ( 200 ).

1 . A collecting device for collection of airborne particles from a flow of air, said collecting device comprising:
 a first layer and a second layer, wherein the first layer and the second layer are arranged to be spaced apart for forming a particle collection chamber between the first and the second layer,   wherein the first layer comprises a plurality of inlets configured to extend through the first layer for transporting the flow of air therethrough into the particle collection chamber;   wherein ends of the inlets are configured to face a first surface of the second layer for capturing airborne particles in the flow of air entering the particle collection chamber through the ends of the inlets by impaction of airborne particles on the first surface of the second layer;   wherein the second layer comprises a plurality of outlets configured to extend through the second layer for transporting the flow of air therethrough out of the particle collection chamber;   wherein the inlets and outlets are staggered such that the center axes of the inlets are displaced from the center axes of the outlets;   wherein the collecting device is configured such that the flow of air experiences a pressure drop when passing the collecting device, the pressure drop being lower than 3 kPa at a flow rate of 0.5 liters per second.   
     
     
         2 . The collecting device according to  claim 1 , wherein a volume of the particle collection chamber is smaller than 30 μl, such as smaller than 20 μl. 
     
     
         3 . The collecting device according to  claim 1 , wherein the collecting device is configured such the pressure drop experienced by the flow of air when passing the collecting device is lower than 1.5 kPa at a flow rate of 0.5 liters per second. 
     
     
         4 . The collecting device according to  claim 1 , wherein the collecting device is configured to provide a collection efficiency of at least 50% for particles having a diameter larger than 300 nm when the collecting device receives a flow of air with a flow rate of 0.5 liters per second. 
     
     
         5 . The collecting device according to  claim 1 , wherein a smallest dimension of a cross-section of the inlets is in a range of 20-300 μm, such as in a range of 100-200 μm. 
     
     
         6 . The collecting device according to  claim 1 , wherein a number of inlets is larger than 100, such as larger than 500, such as 1000-2000 inlets. 
     
     
         7 . The collecting device according to  claim 1 , wherein a length of the inlets is in a range of 20-500 μm, such as in a range of 50-300 μm. 
     
     
         8 . The collecting device according to  claim 1 , wherein a cross-section of the inlets is circular or rectangular. 
     
     
         9 . The collecting device according to  claim 1 , wherein a smallest dimension of a cross-section of the outlets is in a range of 20-400 μm, such as in a range of 100-300 μm. 
     
     
         10 . The collecting device according to  claim 1 , wherein a number of outlets is larger than 100, such as larger than 500, such as 1000-2000 outlets. 
     
     
         11 . The collecting device according to  claim 1 , wherein a length of the outlets is in a range of 20-500 μm, such as in a range of 100-300 μm. 
     
     
         12 . The collecting device according to  claim 1 , wherein the first layer and the second layer are spaced apart by a gap in a range of 10-150 μm, such as in a range of 20-100 μm. 
     
     
         13 . The collecting device according to  claim 1 , wherein a projection of the inlets onto the first surface of the second layer form a hexagonal arrangement of the inlets surrounding each outlet. 
     
     
         14 . The collecting device according to  claim 1 , wherein a projection of an inlet onto the first surface of the second layer is configured not to overlap with a closest neighbor outlet, such as a lateral separation of an edge of the projection of the inlet to an edge of the closest neighbor outlet being at least 20 μm. 
     
     
         15 . A method for collection of airborne particles from a flow of air, said method comprising:
 receiving a flow of air onto a first layer of a collecting device, wherein the first layer comprises a plurality of inlets extending through the first layer;   passing the flow of air through the inlets into a particle collection chamber between the first layer and a second layer of the collecting device spaced apart from the first layer;   capturing airborne particles in the flow of air entering the particle collection chamber by impaction of airborne particles on a first surface of the second layer, wherein ends of the inlets are configured to face the first surface of the second layer;   passing the flow of air out of the particle collection chamber through outlets extending through the second layer of the collecting device;   wherein the inlets and outlets are staggered such that the center axes of the inlets are displaced from the center axes of the outlets;   wherein the collecting device is configured such that the flow of air experiences a pressure drop when passing the collecting device, the pressure drop being lower than 3 kPa at a flow rate of 0.5 liters per second.