Apparatus and method for draining reservoirs

Abstract

An apparatus for draining reservoirs includes a pump disposed in contact with a lower surface of the vessel to be drained, wherein the pump is connected to a discharge pipe inserted into the vessel through an insertion tube connected to a retrofit assembly of the vessel. The apparatus also includes seals within the insertion tube and within the discharge pipe to prevent gases from within the vessel from passing through the insertion tube and discharge pipe and into the atmosphere. An expansion joint unit attaches to the discharge pipe to prevent the rotation of the pump relative to the discharge pipe. The expansion joint unit also maintains the pump in substantial contact with the lower surface of the vessel even when thermal expansion causes the vessel to expand and the position of the discharge pipe to lift.

1 . A method for removing residual cryogenic liquid from a cryogenic reservoir having an instrumentation access duct with a measurement instrument configured to be lowered into the reservoir, comprising the steps of: 
 removing the measurement instrument from the instrumentation access duct;    installing a first valve to an upper end of the instrumentation access duct, the first valve having at least a closed position in which the interior of the reservoir is sealed from the atmosphere;    attaching an adapter member upstream of the first valve with the first valve in a closed position;    inserting a first end of a first pump discharge pipe into an insertion tube so as to generate a seal between the first pump discharge pipe and an interior surface of the insertion tube and with the interior of the first pump discharge pipe being blocked, the first pump discharge pipe also including a pump at the first end;    inserting the insertion tube into the adapter member so as to generate a seal between an outer surface of the insertion tube and an inner surface of the adapter member;    opening the first valve;    inserting a downstream end of the insertion tube through the first valve;    connecting at least a second pump discharge pipe to a second end of the first pump discharge pipe with an interior of the second pump discharge pipe being blocked;    unblocking the first pump discharge pipe;    inserting at least a portion of the second pump discharge pipe through the first valve;    connecting a second end of the second pump discharge pipe to a cryogenic liquid recovery device; and    operating the pump so as to draw cryogenic liquid from the reservoir and pump the liquid through the first and second pump discharge pipes and into the cryogenic liquid recovery device.    
   
   
       2 . A method for draining a reservoir, comprising the steps of: 
 attaching an adapter member to a vessel housing a fluid;    sealingly inserting an insertion tube through said adapter member and into said vessel;    sealingly inserting at least one discharge pipe through said insertion tube into said vessel, wherein the discharge pipe is connected to a pump assembly;    advancing the at least one discharge pipe through the insertion tube to dispose the pump assembly proximal a lower surface of the vessel; and    pumping the fluid through said at least one discharge pipe to a desired location.    
   
   
       3 . The method of  claim 2 , further comprising the step of: 
 circulating an inert gas between the insertion tube and the at least one discharge pipe.    
   
   
       4 . The method of  claim 2 , further comprising the step of: 
 selectively actuating a movable seal, wherein at least a portion of the movable seal is disposed in the discharge pipe, to substantially prevent fluid flow through the discharge pipe.    
   
   
       5 . The method of  claim 4 , wherein the movable seal is a valve.  
   
   
       6 . A retrofit pump assembly for draining a reservoir, comprising: 
 an adapter member configured for attachment to a vessel that houses a fluid;    an insertion duct configured to be slidably and sealedly insertable through said adapter member into said vessel;    at least one discharge pipe configured to be sealedly slidable into said adapter member; and    a pump assembly connected to one end of the at least one discharge pipe.    
   
   
       7 . The retrofit pump assembly of  claim 6 , wherein the pump assembly is disposed adjacent the lower surface of the vessel.  
   
   
       8 . The retrofit pump assembly of  claim 6 , wherein the pump assembly comprises: 
 a motor; and    a pump disposed below said motor and driven by said motor.    
   
   
       9 . The retrofit pump assembly of  claim 6 , further comprising at least one seal disposed between the insertion tube and the adapter member, the seal configured to substantially prevent fluid flow between the insertion tube and the adapter member.  
   
   
       10 . The retrofit pump assembly of  claim 9 , wherein the seal is an O-ring.  
   
   
       11 . The retrofit pump assembly of  claim 6 , further comprising a movable seal, wherein at least a portion of the movable seal is disposed in the discharge pipe, the movable seal selectively actuatable to substantially prevent fluid flow through the discharge pipe.  
   
   
       12 . The retrofit pump assembly of  claim 11 , wherein the movable seal is a balloon.  
   
   
       13 . The retrofit pump assembly of  claim 11 , wherein the movable seal is a valve.  
   
   
       14 . The retrofit pump assembly of  claim 6 , further comprising means for circulating an inert gas between the insertion tube and the at least one discharge pipe.  
   
   
       15 . A retrofit pump assembly for draining a reservoir, comprising: 
 an adapter member configured for attachment to a vessel that houses a fluid;    an insertion tube sized for insertion through said adapter member into said vessel;    at least one discharge pipe connected to said adapter member and extending through said insertion tube into said vessel;    at least one sealing assembly disposed between the discharge pipe and the insertion tube and configured to substantially prevent fluid flow through the insertion tube;    an expansion joint unit connected to the at least one discharge pipe; and    a pump assembly connected to the expansion joint unit and disposed proximal a lower surface of the vessel, the pump assembly configured to pump fluid from said vessel through said discharge pipe to a desired location,    wherein the expansion joint unit is configured to allow an expansion of the at least one discharge pipe and to maintain the pump assembly substantially proximal to the lower surface of the vessel.    
   
   
       16 . The retrofit pump assembly of  claim 15 , wherein the expansion joint unit is configured to allow the at least one discharge pipe to expand about one foot.