GB1285902A - Pumping system for use with, and method of removing a submersible pumping assembly from a closed storage tank - Google Patents

Abstract

1285902 Submersible pumps AIRCO Inc 19 Nov 1969 [19 Nov 1968] 56575/69 Heading F1C A pumping system for a closed storage tank, e.g. a ship's tank or an underground or undersea tank, includes a pump assembly and an isolating chamber through which the assembly can be removed from the tank. A submersible pump and motor assembly 15, Fig. 1, especially for liquefied cryogenic gases, is located in a fixed discharge housing 13 supported adjacent the bottom of a ship's storage tank 28 by rails 17 which additionally act as guide rails during removal and replacement of the assembly from or into the tank. Before removal of the assembly, a cover 21 and an upper sealing plate (43), Fig. 2A (not shown) are removed, whereafter the assembly is raised into an isolation chamber 25 by cable 16 and hoist 24. Then a valve 27 is closed either manually, as by a wheel (89), or by hydraulic, pneumatic or electrical means, to isolate the interior of the chamber 25 from the tank interior. After purging the chamber 25 with inert gas, e.g. nitrogen, and removing two further sealing plates (37, 34), the assembly is lifted out of the chamber 25. The assembly has members 122 which centralize it during entry into chamber 25. Similarly the housing 13 has an upper internal frusto-conical surface (107), Fig. 2B (not shown), which centralizes the assembly when it is lowered back into the housing. The valve 27 can be locked in its closed position by at least one adjustable lug 91. The valve has a counterweight 125 to bias it towards its closed position. The entire discharge system 13, 14 can be removed from the tank by removing support plate 26 from the deck 11.