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NTIS 바로가기국가/구분 | United States(US) Patent 등록 |
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국제특허분류(IPC7판) |
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출원번호 | US-0963952 (1992-10-19) |
발명자 / 주소 |
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출원인 / 주소 |
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인용정보 | 피인용 횟수 : 42 인용 특허 : 0 |
Methods and apparatus are described which permit stage cementing within a well bore by means of a well tool which includes a cementer having cementing ports which may be responsively opened and closed by means of a knife gate valve. The knife gate valve is disposed within the housing between outer a
A well tool for use in stage cementing a well bore, comprising: a. a generally cylindrical housing having a central passageway therethrough and an outer cylindrical wall and inner cylindrical wall; b. a cementing port within said housing adapted to permit fluid communication through said housing; c.
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