Method of inactivating microorganisms in a fluid using ultraviolet radiation

Abstract

A method of inactivating microorganisms such as viruses within a fluid such as a biological fluid is disclosed. The method includes the steps of providing a UV reactor, which may take the form of an elongated generally annular reaction chamber surrounding at least one elongated UV lamp, moving the fluid within the reaction chamber in a primary flow directed along the length of the UV lamp, and inducing a circulating secondary flow within the fluid with the secondary flow being superimposed on the primary flow. As the fluid moves through the reaction chamber in the primary flow, it is circulated repeatedly toward and away from the UV lamp in the circulating secondary flow to provide uniform and controllable exposure of the entire volume of fluid to ultraviolet radiation. Microorganisms such as viruses are thus inactivated while desirable components in the fluid, such as proteins, are preserved without the use of a free radical scavenger.

What is Claimed is:  
     
         1 . A method of irradiating a fluid with ultraviolet radiation from a UV source, said method comprising the steps of: 
 (a) moving the fluid in a primary flow along the UV source; and    (b) inducing within the fluid a circulating secondary flow superimposed on the primary flow, the circulating secondary flow moving the fluid toward and away from the UV source.    
     
     
         2 . The method of  claim 1  and wherein the fluid is a biological fluid, the irradiation inactivating microorganisms within the biological fluid.  
     
     
         3 . The method of  claim 2  and wherein the microorganisms are viruses.  
     
     
         4 . The method of  claim 1  and wherein the fluid is a foodstuffs fluid.  
     
     
         5 . The method of  claim 1  and wherein the UV source is at least one elongated UV lamp and wherein step (a) includes defining a reaction chamber surrounding the UV lamp and moving the fluid in a primary flow along the reaction chamber.  
     
     
         6 . The method of  claim 5  and wherein step (b) comprises moving an agitator within the reaction chamber.  
     
     
         7 . The method of  claim 5  and wherein step (b) comprises disposing irregularities within the reaction chamber.  
     
     
         8 . The method of  claim 7  and wherein the step of defining a reaction chamber around the UV lamp includes surrounding the UV lamp with a housing having a wall, the reaction chamber being defined between the UV lamp and the wall of the housing, and wherein the step of disposing irregularities within the reaction chamber comprises forming irregularities in the wall of the housing.  
     
     
         9 . The method of  claim 1  and wherein the UV source is an elongated UV lamp and wherein step (a) includes disposing a generally spiral tubular conduit around the UV lamp and moving the fluid in a primary flow direction through the tubular conduit, the interaction of the fluid with the conduit inducing the circulating secondary flow of step (b).  
     
     
         10 . A method for inactivating microorganisms in a fluid, said method comprising the steps of: 
 (a) providing a reactor for radiating ultraviolet light into the fluid, the reactor having a reaction chamber connected to at least one inlet and one outlet for the fluid, and an ultraviolet radiation source;    (b) moving the fluid through the reaction chamber in a primary flow generally along the ultraviolet radiation source; and    (c) inducing a circulating secondary flow superimposed on the primary flow, the secondary flow being oriented transversely relative to the ultraviolet radiation source.    
     
     
         11 . The method of  claim 10 , wherein the reaction chamber is disposed around the ultraviolet radiation source.  
     
     
         12 . The method of  claim 10 , wherein the ultraviolet radiation source is disposed around the reaction chamber.  
     
     
         13 . The method of  claim 10 , wherein the irradiation space of the reactor is a ring-shaped tubular space defined by a housing and an inner tube and having a longitudinal axis therein.  
     
     
         14 . The method of  claim 10 , wherein the reaction chamber is formed by a tubular conduit and wherein the tubular conduit spirals around the ultraviolet radiation source.  
     
     
         15 . The method of  claim 10 , wherein the reaction chamber is defined between an outer cylindrical wall and a UV transparent inner cylindrical wall, the ultraviolet source being surrounded by the inner cylindrical wall.  
     
     
         16 . The method of  claim 10 , wherein the microorganism to be inactivated is a virus.  
     
     
         17 . The method of  claim 10 , wherein the ultraviolet radiation is UVC radiation.  
     
     
         18 . The method of  claim 10 , wherein the wavelength of the ultraviolet radiation is about 254 nm.  
     
     
         19 . The method of  claim 16 , wherein the fluid is exposed to a viral inactivating less than about 30 Joules/cm 2 .  
     
     
         20 . The method of  claim 16 , wherein the fluid is exposed to a viral inactivating fluency between about 0.01 Joules/cm 2  and about 10 Joules/cm 2 .  
     
     
         21 . The method of  claim 16 , wherein the fluid is exposed to a viral inactivating fluency between about 0.02 Joules/cm 2  and about 5 Joules/cm 2 .