Tank with reinforced bottom joint

Abstract

A tank includes a bottom portion with an upwardly extending annular flange having a reduced thickness at an end portion as compared to a lower portion. A generally cylindrical sidewall portion has an end portion disposed within the annular flange and forms a joint therewith. An internal overlaminate piece is bonded about an inner circumference of the joint. An external overlaminate piece is bonded about an outer circumference of the joint.

What is claimed is: 
     
         1 . A tank comprising:
 a bottom portion with an upwardly extending annular flange having a reduced thickness at an end portion as compared to a lower portion,   a generally cylindrical sidewall portion having an end portion disposed within the annular flange and forming a joint therewith,   an internal overlaminate piece bonded about an inner circumference of the joint, and   an external overlaminate piece bonded about an outer circumference of the joint.   
     
     
         2 . The tank according to  claim 1 , wherein the end portion of the upwardly extending annular flange is tapered. 
     
     
         3 . The tank according to  claim 1 , wherein the end portion of the generally cylindrical sidewall portion is tapered. 
     
     
         4 . The tank according to  claim 1 , further comprising a reinforcing fiberglass stitched mat disposed within the bottom portion. 
     
     
         5 . The tank according to  claim 1 , further comprising a reinforcing fiberglass stitched mat disposed within one of the internal overlaminate piece and the annular flange. 
     
     
         6 . The tank according to  claim 1 , further comprising a reinforcing fiberglass stitched mat disposed within one of the internal overlaminate piece and the end portion. 
     
     
         7 . A tank comprising:
 a bottom portion with an upwardly extending annular flange having a reduced thickness at an end portion as compared to a lower portion,   a generally cylindrical sidewall portion having a first end portion and a second end portion with a main sidewall extending therebetween, the first end disposed within the annular flange and forming a joint therewith,   a top portion disposed about the second end.   an internal overlaminate piece bonded about an inner circumference of the joint, and   an external overlaminate piece bonded about an outer circumference of the joint.   
     
     
         8 . The tank according to  claim 7  further comprising a manway disposed in the sidewall portion between the first end portion and the second end portion. 
     
     
         9 . The tank according to  claim 7 , further comprising a reinforcing fiberglass stitched mat disposed within the bottom portion. 
     
     
         10 . The tank according to  claim 7 , further comprising at least one valve disposed in the top portion. 
     
     
         11 . The tank according to  claim 7 , wherein the end portion of the annular flange is tapered. 
     
     
         12 . The tank according to  claim 7 , where in the first end portion of the generally cylindrical sidewall portion is tapered. 
     
     
         13 . A method of manufacturing a tank comprising:
 forming a bottom portion with an upwardly extending annular flange having a reduced thickness at an end portion as compared to a lower portion,   forming a generally cylindrical sidewall portion having a first end portion and extending upwardly to a second end portion,   forming a top portion,   bonding the top portion to the second end portion of the sidewall portion,   bonding the annular flange to the first end portion of the sidewall portion to form a joint,   bonding an internal overlaminate piece about an inner circumference of the joint, and   bonding an external overlaminate piece about an outer circumference of the joint.   
     
     
         14 . The method of  claim 13 , further comprising:
 placing a layer of fiberglass stitched mat within the internal overlaminate piece and the annular flange.   
     
     
         15 . The method of  claim 13 , further comprising:
 placing a layer of fiberglass stitched mat within the internal overlaminate piece and the first end.   
     
     
         16 . The method of  claim 13 , further comprising:
 forming an aperture in the sidewall portion between the first end portion and the second end portion, and   fixing a manway about the aperture.