검색연산자 | 기능 | 검색시 예 |
---|---|---|
() | 우선순위가 가장 높은 연산자 | 예1) (나노 (기계 | machine)) |
공백 | 두 개의 검색어(식)을 모두 포함하고 있는 문서 검색 | 예1) (나노 기계) 예2) 나노 장영실 |
| | 두 개의 검색어(식) 중 하나 이상 포함하고 있는 문서 검색 | 예1) (줄기세포 | 면역) 예2) 줄기세포 | 장영실 |
! | NOT 이후에 있는 검색어가 포함된 문서는 제외 | 예1) (황금 !백금) 예2) !image |
* | 검색어의 *란에 0개 이상의 임의의 문자가 포함된 문서 검색 | 예) semi* |
"" | 따옴표 내의 구문과 완전히 일치하는 문서만 검색 | 예) "Transform and Quantization" |
다음과 같은 기능을 한번의 로그인으로 사용 할 수 있습니다.
NTIS 바로가기국가/구분 | United States(US) Patent 등록 |
---|---|
국제특허분류(IPC7판) | E21B-034/00 |
미국특허분류(USC) | 166/327 ; 166/332 |
출원번호 | US-0963952 (1992-10-19) |
발명자 / 주소 | |
출원인 / 주소 | |
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 and inner cylindrical walls and being slidable therein between an open position, wherein the cementing port is open and fluid may be communicated therethrough, and a closed position, wherein the cementing port is closed thus blocking fluid communication through...
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. a knife gate valve within said housing, said knife gate valve located between said outer and inner cylindrical walls and being slidable therein between an open position, wherein the cementing port is open, and a closed position, wherein the cementing port is ...