Floating apparatus for downhole use and method of making it

摘要

A floating apparatus for a well casing includes a check valve (30) disposed in a sleeve (32), wherein the sleeve (32) is receivable within an outer case (14). The outer case comprises coupled upper (16) and lower (18) casing string sections. The check valve (30) includes a valve housing (44), wherein a first cement body portion (78) attaches the valve housing (44) to the sleeve (32). The sleeve (32) includes an annular flange (38) that extends outwardly therefrom and is received between ends of the coupled upper (16) and lower (18) casing string sections for holding the sleeve (32) and affixed valve (30) within the outer case (14). A seal (40) is provided between the flange (38) and upper (16) casing string section. A second cement body portion can be provided for attachment of the sleeve to the outer case, thereby to hold the sleeve (32) and affixed valve (30) within the outer case which is threadably connectable with the well casing. Preferably, the second cement body portion only partially fills an annulus between the sleeve and outer case, wherein the well casing is received in the annulus when threadably connected to the outer case.