US PATENT SUBCLASS 166 / 327-- .~.~.~ Shoes with check valve

US PATENT SUBCLASS 166 / 327
.~.~.~ Shoes with check valve

Current as of: June, 1999
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166 /	HD	WELLS

316	DF	VALVES, CLOSURES OR CHANGEABLE RESTRICTORS {5}
319	DF	.~ Fluid operated {4}
325	DF	.~.~ One way, e.g., check valve type {2}
327		.~.~.~ Shoes with check valve {1}
328	DF	.~.~.~.~> Loose ball closure

DEFINITION

Classification: 166/327

(under subclass 325) Devices comprising annular or blunt nosed means (usually known as casing shoes) at the end of a well conduit for facilitating its entrance into the well combined with a valve which is opened by fluid pressure acting directly on it and which returns to its original position when the pressure is removed.

SEE OR SEARCH THIS CLASS, SUBCLASS:

143+, for a shoe with a check valve attached to a casing or strainer section having a packer, and detachably connected to a setting string.

157+, for a shoe with check valve attached to a screen for washing the screen.

SEE OR SEARCH CLASS

137, Fluid Handling,

515, for check valves in couplings joining sections of a well conduit. These devices, usually known as float collars, are often very similar in structure to the float plugs or cement shoes of this subclass (327) of Class 166.