Urea storage system

Abstract

A urea storage system comprising a storage tank for a urea solution is provided. The system comprises a heated reservoir, a channel connecting the storage tank to the heated reservoir and a pump for drawing urea from the heated reservoir. A second pump including an actuator comprising a memory shape metal for drawing urea from the storage tank to the heated reservoir is also provided.

1  A urea storage system comprising;
 a storage tank for a urea solution;   a heated reservoir;   a channel connecting said storage tank to said heated reservoir;   a pump for drawing urea from said heated reservoir; and   a second pump including an actuator comprising a memory shape metal for drawing urea from said storage tank to said heated reservoir.   
   
   
       2 . The urea storage system of  claim 1 , wherein said heated reservoir is disposed within said storage tank. 
   
   
       3 . The urea storage system of  claim 1 , wherein said heated reservoir has a first pressure head and said storage tank has a second pressure head, said first pressure head being greater than said second pressure head. 
   
   
       4 . The urea storage system of  claim 1 , including a drawpipe disposed within said heated reservoir and connected to said second pump. 
   
   
       5 . The urea storage system of  claim 1 , wherein said reservoir comprises a first portion and a second portion, said channel disposed between said first portion and said second portion. 
   
   
       6 . The urea storage system of  claim 5 , wherein said first portion is cylindrical and said second portion is cylindrical and concentric to said first portion, said channel being partially circumferential and disposed between said first portion and said second portion. 
   
   
       7 . The urea storage system of  claim 1 , wherein said second pump includes a pump cavity having a first valve in fluid communication with said storage tank and a second valve in fluid communication with said reservoir. 
   
   
       8 . The urea storage system of  claim 7 , wherein said actuator comprises a piston disposed in said cavity and attached to said shape memory metal. 
   
   
       9 . The urea storage system of  claim 8 , wherein said piston has a first position and a second position, said first position opening said first valve, said second position opening said second valve. 
   
   
       10 . The urea storage system of  claim 7 , wherein one of said first valve and said second valve is an umbrella valve. 
   
   
       11 . The urea storage system of  claim 1 , wherein said actuator comprises a piston and said shape memory metal is a shape memory wire, said shape memory wire attached to said piston. 
   
   
       12 . The urea storage system of  claim 1 , wherein said actuator comprises a piston having a first position in which said shape memory metal is electrically energized and a second position in which said shape memory metal is de-energized. 
   
   
       13 . The urea storage system of  claim 1 , wherein said actuator includes a spring in contact with said piston, said spring actuating said piston from said first position from said first position to said second position. 
   
   
       14 . A method of pumping urea solution in a urea storage system comprising:
 providing a urea storage tank;   providing a urea reservoir fluidly connected to said storage tank;   providing a pump including an actuator interposed between said storage tank and said reservoir;   moving said actuator to a first position by energizing a shape memory metal attached to said actuator;   moving said actuator to a second position by de-energizing the shape memory metal attached to said actuator of said pump and decompressing a spring in contact with said actuator.   
   
   
       15 . The method of  claim 14 , including opening a first valve in fluid communication with said storage tank upon moving said actuator to said first position and opening a second valve in fluid communication with said reservoir upon moving said actuator to said second position. 
   
   
       16 . The method of  claim 14 , including heating said urea in said urea reservoir. 
   
   
       17 . The method of  claim 14 , including expelling said urea from said pump into said reservoir and heating said urea therein. 
   
   
       18 . The method of  claim 14 , including pressurizing said reservoir to a pressure head greater than a pressure head within said storage tank.