Substance detection device utilizing a cyclone particle separator

Abstract

A substance detection device, including a chemical substance analyzer, including an ion mobility spectrometer (IMS), a desorber, a conduit, and a membrane. The membrane extends across a cross-section of the conduit, and the membrane is positioned to have a desorber side in gas communication with the desorber and an analysis side opposite the desorber side. The substance detection device can be configured to direct a portion of a chemical substance to the desorber through the conduit so that at least a portion of the entrained chemical substance is transferred to the membrane by interacting with the desorber side of the membrane. The membrane is adapted to diffuse at least a portion of the chemical substance transferred to the membrane through the membrane to the analysis side. The device also includes a particle separator including a protuberance extending into a collection chamber of the particle separator.

What is claimed is: 
     
         1 . A method for collecting particles in a cyclone, comprising:
 (a) providing a cyclone comprising a collection chamber having a first side and a second side with respect to a longitudinal axis of the collection chamber;   (b) causing a particle to become entrapped in a sample collection fluid to generate a particle-sample collection fluid mixture;   (c) moving the particle-sample collection fluid mixture in a first direction towards the first side of the collection chamber;   (d) moving the particle-sample collection fluid mixture in a second direction towards the second side of the collection chamber; and   (e) collecting the particle-sample collection mixture.   
     
     
         2 . The method of  claim 1 , wherein a particle outlet passage is located at the first side of the collection chamber. 
     
     
         3 . The method of  claim 2 , further comprising, between steps (d) and (e), moving the particle-sample collection mixture through the particle outlet passage in the first direction. 
     
     
         4 . The method of  claim 2 , wherein the collection chamber is configured to rotate about a rotated axis, and the particle outlet passage is substantially aligned on the rotation axis. 
     
     
         5 . The method of  claim 1 . wherein an internal surface of the collection chamber at the first side of the collection chamber is in the form of a protuberance extending into the collection chamber. 
     
     
         6 . The method of  claim 5 , wherein step (d) is performed by moving the particle-sample collection fluid mixture in the second direction over an outer surface of the protuberance. 
     
     
         7 . The method of  claim 5 , wherein a particle outlet passage is located at the first side of the collection chamber and extends through the protuberance. 
     
     
         8 . The method of  claim 7 , wherein a particle outlet of the particle outlet passage is located at a crest of the protuberance. 
     
     
         9 . The method of  claim 8 ,
 wherein step (c) is performed by moving the particle-sample collection fluid mixture in the first direction along an inner surface of the collection chamber,   wherein step (d) is performed by moving the particle-sample collection fluid mixture in the second direction over an outer surface of the protuberance, and   wherein the method further comprises, between steps (d) and (e), moving the particle-sample collection mixture through the particle outlet passage in the first direction.   
     
     
         10 . The method of  claim 7 , wherein step (e) includes sucking the particle-sample collection fluid mixture into the particle outlet passage using a suction device. 
     
     
         11 . The method of  claim 5 , wherein the protuberance is conical. 
     
     
         12 . The method of  claim 11 , wherein the conical protuberance is truncated at a narrow end of the protuberance to have a flat surface, and wherein a particle outlet of the particle outlet passage is located on the flat surface. 
     
     
         13 . The method of  claim 5 , wherein the protuberance extends from a substantially flat surface of a lateral wall of the collection chamber in a direction towards the second side of the collection chamber. 
     
     
         14 . The method of  claim 13 , wherein the protuberance extends in a continuous curve from the substantially flat surface. 
     
     
         15 . The method of  claim 13 , wherein the protuberance includes a sloped surface extending from the substantially flat surface at an angle of about 135°. 
     
     
         16 . The method of  claim 1 , wherein the collection chamber is an elongated chamber adapted to swirl the particle-sample collection fluid about a rotation axis of the collection chamber. 
     
     
         17 . The method of  claim 1 , further comprising driving gas out of the collection chamber through a gas outlet conduit. 
     
     
         18 . The method of  claim 17 , wherein the gas outlet conduit has a substantially constant internal diameter. 
     
     
         19 . The method of  claim 17 , wherein an end of the gas outlet conduit facing the first side tapers internally so as to form a flared opening. 
     
     
         20 . The method of  claim 1 , wherein the second direction is substantially opposite from the first direction.