Passive adsorption microvacuum pump and microsystem containing the same

Abstract

A micro-absorption pump can be used to form microsystems with microdevices such as a mass spectrometer, micro chromatograph, micro crack sensing devices which can be used in microcrack detection of large aeroplane and other structures and chemical or gas sensing lab-on-chip devices, which need evacuation prior to their use. The micro-absorption pump has a chamber containing a cooled absorbent material which is capable of retaining gas molecules on a surface and reducing the pressure of the atmosphere containing the gas molecules. The absorbent is cooled by a liquid, such as liquid nitrogen, or a peltier device and the absorbed gas can be released by heating the absorbent. The micro-absorption pump can be connected to the microdevice to create a low-pressure environment therein.

1 . A micro-sorption pump comprising:
 a base wall made of a thermally conductive material;   a first continuous vertically-extending wall made of the thermally conductive material provided on the base wall and enclosing a first space therein;   a second continuous vertically-extending wall made of the thermally conductive material provided on the base wall inside the first wall and enclosing a second space therein, the first and second walls defining a chamber therebetween;   cooling fins provided on the second wall and extending into the second space; and   an adsorbent material contained in the second space.   
   
   
       2 . The micro-sorption pump of  claim 1 , additionally comprising a means for cooling the adsorbent contained in the chamber. 
   
   
       3 . The micro-sorption pump of  claim 1 , wherein said base wall has a circular configuration and said first and second walls have annular configurations. 
   
   
       4 . The micro-sorption pump of  claim 2 , wherein the means for coding the adsorbent material is a liquid. 
   
   
       5 . The micro-sorption pump of  claim 4 , wherein said liquid is liquid nitrogen. 
   
   
       6 . The micro-sorption pump of  claim 2 , wherein the means for coding the adsorbent material is a peltier device. 
   
   
       7 . The micro-sorption pump of  claim 1 , additionally comprising a rupturable seal for sealing the second space from the outside. 
   
   
       8 . The micro-sorption pump of  claim 1 , wherein said thermally conductive material is selected from the group consisting of copper, nickel, copper-nickel alloys, nickel-iron alloys and silicon. 
   
   
       9 . The micro-sorption pump of  claim 1 , wherein the cooling fins have rounded ends. 
   
   
       10 . The micro-sorption pump of  claim 1 , wherein the adsorbent material is selected from the group consisting of a carbon molecular sieve and a zeolite molecular sieve. 
   
   
       11 . The micro-sorption pump of  claim 1 , wherein the second space has an aspect ratio of from 1,000:50-250. 
   
   
       12 . A micro-sorption pump comprising:
 a base wall made of a thermally conductive material;   a continuous vertically-extending wall made of the thermally conductive material provided on the base wall and enclosing a space therein for containing an adsorbent material;   cooling fins provided on the continuous vertically extending wall and extending into the space for containing an adsorbent material;   an adsorbent material contained in the space; and   a micropeltier unit for cooling the continuous vertically-extending wall.   
   
   
       13 . The micro-sorption pump of  claim 12 , wherein the micropeltier unit comprises a chamber having walls which are in thermal contact with the continuous vertically extending wall. 
   
   
       14 . A microsystem comprising a microdevice integrated with the micro-sorption pump of  claim 1 . 
   
   
       15 . The microsystem of  claim 14 , wherein the microdevice is a mass spectrometer. 
   
   
       16 . The microsystem of  claim 14 , wherein the microdevice is selected from the group consisting of a micro chromatograph, micro crack sensing device and a chemical or gas sensing lab-on-chip device. 
   
   
       17 . The microsystem of  claim 14 , additionally comprising a sleeve for mounting the micro-sorption pump to the microdevice. 
   
   
       18 . The microsystem of  claim 14 , wherein the micro-sorption pump comprises a seal for sealing the second space from the outside and the microdevice has a perforating member for breaking the seal and bringing the second space into communication with a microchannel contained in the microdevice. 
   
   
       19 . A microsystem comprising a microdevice integrated with the micro-sorption of  claim 12 .