Method of detecting the presence of impurities, unit and method for vaporizing liquid, and double air distillation column

Abstract

A film-type vaporizer ( 2 ) in a vaporization enclosure ( 1 ), for example the upper column of a double air-distillation column, is associated with a measurement and analysis box ( 3 ) where a polished surface ( 4 ) and a spillway ( 6 ) reconstruct the flow of liquid in the vaporizer in order to check for the absence of the deposition of impurities in the liquid that is to be evaporated or, if such a deposition occurs, to quantify and analyse the impurities involved and take appropriate action on the settings of the machine. Application in particular to the distillation of air for the production of oxygen

What is claimed is:  
     
         1 . A vaporizing unit comprising, within an enclosure: 
 at least one vaporizer;    means of supplying the vaporizer with a stream of liquid to be vaporized;    a circuit for diverting part of the stream to be vaporized, the circuit being connected to the supply means and comprising a means of spraying part of the diverted stream onto a receiving surface; and    means of detecting the formation of solid deposits on the receiving surface.    
     
     
         2 . The unit according to  claim 1 , wherein the enclosure comprises a distillation column.  
     
     
         3 . The unit according to  claim 2 , wherein the supply means consists of a spillway in the column.  
     
     
         4 . The unit according to  claim 1 , wherein the receiving surface is polished.  
     
     
         5 . The unit according to  claim 2 , wherein the supply means comprises a pump for recirculating the liquid at the bottom of the column.  
     
     
         6 . The unit according to  claim 5 , further comprising a filter module between the pump and the diversion circuit.  
     
     
         7 . A double air-distillation column comprising a vaporizing unit according to  claim 2 .  
     
     
         8 . A double air-distillation column comprising, at the base of an upper column, a vaporizer without a recirculating pump.