Method and apparatus for removing sludge deposits from oil storage tanks

1. A method for retrofitting an assembly on a tank, having a manway cover, for removing sludge deposits in the tank, the method comprising:

attaching a flange member onto the manway cover;

connecting a valve to the flange member;

connecting a first end of a spool to the valve;

connecting a cover having an opening passing therethrough to a second end of the spool;

passing a hole saw through the opening in the cover, opening the valve, passing the hole saw through the open valve, and using the hole saw to cut a hole in the manway cover;

retracting the hole saw back through the valve and closing the valve;

removing the cover and installing a jet nozzle passing through the opening in the cover;

reattaching the cover to the second end of the spool with the jet nozzle extending inside the spool; and

opening the valve and passing the jet nozzle through the open valve and the hole in the manway cover to extend into the tank.

2. The method of claim 1 wherein the jet nozzle comprises:

a rigid conduit having a proximal end and a connection end, the connection end connectable to a pressurized liquid supply and the rigid conduit sized to slide through the opening in the cover of the assembly;

a pivotal connection connected the proximal end of the rigid conduit;

a spray nozzle having a proximal end and a discharge end, the proximal end of the spray nozzle connected to the pivotal connection so that the spray nozzle can pivot around the proximal end of the spray nozzle; and

at least one movement actuator operative to pivot the spray nozzle around the pivotal connection, and wherein the jet nozzle is installed in the cover with the rigid conduit passing through the opening in the cover.

3. The method of claim 1 , and further comprising welding the flange member to the manway cover.

4. The method of claim 1 , and further comprising forming the rigid conduit with a length that is longer than a length of the assembly.

5. The method of claim 1 , wherein the pivotal connection is a ball and socket.

6. The method of claim 1 , and further comprising operatively connecting a first hydraulic cylinder between the rigid conduit and the spray nozzle so that the first hydraulic cylinder pivots the spray nozzle around the pivotal connection in a first direction.

7. The method of claim 6 , and further comprising operatively connecting a second hydraulic cylinder between the rigid conduit and the spray nozzle so that the second hydraulic cylinder pivots the spray nozzle around the pivotal connection in a second direction.

8. The method of claim 6 , wherein the first direction is vertical relative to the rigid conduit and the second direction is horizontal relative to the rigid conduit.

9. The method of claim 1 , wherein the pressurized liquid supply is a hose.

10. The method of claim 1 , and further comprising providing a guide plate on the rigid conduit.

11. The method of claim 1 , and further comprising providing an opening in a cover, wherein the opening sized to allow the rigid conduit to slide through the opening.

12. The method of claim 11 , and further comprising: operably connecting a feed actuator between the rigid conduit and the cover; and forcing the rigid conduit through the opening in the cover with the feed actuator.

13. The method of claim 12 , wherein the feed actuator is a hydraulic cylinder.

14. The method of claim 1 , and further comprising forming a seal between the opening and the rigid conduit when the rigid conduit is positioned through the opening.