Ice nucleii counter technology

Abstract

A method and system of measuring the size distribution of particles within dilute colloids, for example, through variation of the minimum ice-nucleation sizes of particles within the colloid. The system for measuring particles in fluids includes, a sample fluid inlet and an ice nuclei counter communicatively connected to the sample fluid inlet, the ice nuclei counter cooling the sample fluid and measuring particles which form crystals in the cooled fluid. The method for measuring particles in fluid includes the steps of providing a sample fluid, cooling the sample fluid, and measuring particles which form crystals in the cooled fluid.

What is claimed is: 
     
         1 . An apparatus for measuring particles in fluids, comprising, a sample fluid inlet and an ice nuclei counter communicatively connected to the sample fluid inlet, the ice nuclei counter cooling the sample fluid and measuring particles which form crystals in the cooled fluid. 
     
     
         2 . The apparatus of  claim 1 , wherein the sample fluid is a colloid. 
     
     
         3 . The apparatus of  claim 2 , wherein the colloid is dilute colloid. 
     
     
         4 . The apparatus of  claim 3 , wherein the sample fluid is ultra pure water containing less than 1 ppb of non-volatile residue where the concentration of particles greater than 10 nm in diameter is less than 1e6#/ml. 
     
     
         5 . The apparatus of  claim 1 , wherein the ice nuclei counter measures the size distribution of particles and the concentration of particles, and wherein the ice nuclei counter measures particles less than 20 nm in diameter. 
     
     
         6 . The apparatus of  claim 1 , wherein the ice nuclei counter comprises a sheathing fluid inlet communicatively connected to the sample fluid inlet for sheathing the sample fluid in an immiscible sheathing fluid having a predetermined freezing point, a nucleation cell, having at least one wall, for passage of the sheathed, sample fluid, a chiller for temporally, adjustably cooling the nucleation cell, and a detector for detecting crystals in the cooled, sheathed sample fluid. 
     
     
         7 . The apparatus of  claim 1 , wherein the chiller is a spatial chiller and the detector is arranged in an array. 
     
     
         8 . The apparatus of  claim 6 , wherein the sheathing fluid is selected from the group of fluids consisting of FLOURINERT coolant liquid and NOVEC engineered fluid. 
     
     
         9 . The apparatus of  claim 6  wherein the defector is an optical detector. 
     
     
         10 . The apparatus of  claim 6 , wherein the sheathed sample fluid is cooled to a predetermined temperature which is lower than the freezing temperature of the sample fluid, whereby it is supercooled, and ice crystals are detected. 
     
     
         11 . The apparatus of  claim 10 , wherein temperature of the sheathed sample fluid is cooled by varying the temperature of the nucleation cell wall. 
     
     
         12 . The apparatus of  claim 11 , wherein the temperature is held at a fixed point. 
     
     
         13 . The apparatus of  claim 11 , wherein the temperature is varied stepwise. 
     
     
         14 . The apparatus of  claim 11 , wherein the temperature is varied and measured throughout a transition period and a minimum nucleated particle size is interred from the measured temperatures. 
     
     
         15 . The apparatus of  claim 10 , wherein the detection limit is varied by adjusting the temperature of the sheathing fluid. 
     
     
         16 . The apparatus of  claim 15 , wherein the temperature is varied stepwise. 
     
     
         17 . The apparatus of  claim 15 , wherein the temperature is varied and measured throughout a transition period and a minimum nucleated particle size is inferred from the measured temperatures. 
     
     
         18 . The apparatus of  claim 10 , wherein the sheathed, sample fluid is spatially cooled in the nucleation cell to progressively lower temperatures below the freezing temperature of the sample fluid. 
     
     
         19 . The apparatus of  claim 18 , wherein the temperature is held at a fixed point. 
     
     
         20 . The apparatus of  claim 18 , wherein the temperature is varied stepwise. 
     
     
         21 . The apparatus of  claim 18 , wherein the temperature is varied and measured throughout the transition period and a minimum nucleated particle size is inferred from the measured temperatures. 
     
     
         22 . The apparatus of  claim 1 , further comprising a colloid concentrator disposed between the sample fluid inlet and the ice nuclei counter. 
     
     
         23 . The apparatus of  claim 22 , wherein the colloid concentrator is a cross flow filtration concentrator. 
     
     
         24 . The apparatus of  claim 22 , wherein the colloid concentrator is an evaporative concentrator. 
     
     
         25 . The apparatus of  claim 24 , wherein sample fluid is evaporated through a semi porous membrane. 
     
     
         26 . The apparatus of  claim 24 , wherein the sample fluid is evaporated by bathing it in a hot, dry gas. 
     
     
         27 . The apparatus of  claim 24 , wherein the sample fluid is evaporated by exposing it to a hot, dry gas. 
     
     
         28 . The apparatus of  claim 6 , further comprising a sheathing fluid recovery assembly. 
     
     
         29 . The apparatus of  claim 28 , wherein the sheathing fluid recovery assembly includes a tank wherein sample fluid and sheathing fluid separate, sheathing fluid is drawn from the tank and recycled to the ice nuclei counter, and waste sample fluid drains from the assembly. 
     
     
         30 . A method for measuring particles in fluids, comprising the steps of providing a sample fluid, cooling the sample fluid, and measuring particles which form crystals in the cooled fluid. 
     
     
         31 . The method of  claim 30  wherein the provided sample fluid is a colloid. 
     
     
         32 . The method of  claim 30  further comprising the step of adding a secondary fluid to the sample fluid, the secondary fluid being substantially immiscible with in the sample fluid and having a predetermined freezing temperature. 
     
     
         33 . The method of  claim 32  wherein the combined sample and secondary fluid are cooled to a temperature which is lower than the freezing temperature of the sample fluid, and then ice crystals are measured. 
     
     
         34 . The method of  claim 33 , wherein the temperature of the combined sample and secondary fluid is held at a fixed temperature. 
     
     
         36 . The method of  claim 33 , wherein the temperature is adjusted in a stepwise manner. 
     
     
         35 . The method of  claim 33 , wherein the temperature is adjusted and measured throughout a transition period and a minimum particle nucleation size is inferred from the measured temperatures. 
     
     
         36 . The method of  claim 32 , wherein the detection limit is varied by adjusting the temperature of the secondary fluid. 
     
     
         37 . The method of  claim 36 , wherein the temperature is adjusted in a stepwise manner. 
     
     
         38 . The method of  claim 36 , wherein the temperature is adjusted and measured throughput the transition period and a minimum particle nucleation size is inferred from the measured temperatures. 
     
     
         39 . The method of  claim 30  wherein the step of measuring particles which form crystals in the cooled fluid is accomplished optically. 
     
     
         40 . The method of  claim 30  further comprising the step of recycling the secondary fluid.