| 摘要 |
1,125,130. Boring earth; wells. STABILATOR A.B. 10 Dec., 1965 [22 Dec., 1964], No. 52612/65. Heading E1F. A tube for cementing into a borehole has apertured walls for the outward flow of cement, the apertures being closed by resilent, preferably metallic, flaps on the outside of the tube. The tube may also be used for drilling the borehole. |
