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익스팬딩 게이트 밸브

익스팬딩 게이트 밸브는 기계적으로 밀폐합니다: 게이트 어셈블리가 폐쇄 시 양쪽 시트 쪽으로 팽창하여 관내 압력에 독립적인 양방향 토크 기반 밀폐를 제공하고, 어셈블리는 이동 중 시일면 사이를 자유롭게 통과해 마모를 줄이고 수명을 연장합니다 — 고온·고압 파이프라인에서 기밀 차단이 요구되는 선택입니다. 범위는 NPS 2"~12"(DN50~DN300), ASME Class 300~2500(PN40~PN420)으로, 탄소강·스테인리스강·합금강·듀플렉스 스테인리스 바디, RF·BW·RTJ 단자 접속, 수동·공압·전동·유압 조작, API 6D 설계를 제공합니다. 설계 디테일이 이 성능 여유를 만듭니다: 시트 링은 바깥쪽을 향하고 단부 위치에서만 맞물리며(캠으로 고정된 게이트 세그먼트가 마찰 없이 이동하므로 부분 행정으로도 시트가 마모되지 않음), 시일은 스템 스러스트만으로 조여집니다 — 압력 보조 없이도 차압 0에서 양방향 버블타이트이며, 완전 개방 보어는 배관과 같은 압력 강하로 피그를 통과시키는 연속 컨듀잇입니다. 폐쇄 시 양쪽 시트를 동시에 밀폐하므로, 그 사이 캐비티는 더블 블록 앤 블리드 격리를 위해 배수 또는 환기할 수 있습니다. 대표적인 고장 경로는 액체 서비스에서의 열성 캐비티 과압(캐비티 릴리프를 장착하고 니들 밸브를 열어 두십시오), 시운전 시 시트 인서트에 흠집을 내는 이물(기동 전 라인을 플러싱하고 사이클링하십시오), 이미 웨지가 무거운 토크를 부풀리는 글랜드 과조임입니다. 수평 라인에 핸드휠이 중심선 위로 가도록 수직으로 설치하고, 설치 전 전개/전폐 사이클을 돌려 게이트 메커니즘의 저항을 확인하며, 바디 중앙의 두 인젝션 포트(관내 압력보다 약 300 psi 이내로 유지)를 비상 2차 시일로만 다루고, 폐쇄 후 캐비티 감압 확인에는 보닛 벤트를 사용하십시오. 두 API 프레임을 구분하십시오: ISO 5208 누출 등급의 API 6D 파이프라인 밸브(페이스 투 페이스 API 6D/ASME B16.10, 버트 용접 단자 B16.25, 정격 B16.34)와 API 6A의 더 작은 웰헤드 밸브 — 상호 교환되지 않습니다. 선정은 라인에 대한 사이즈 밴드, 최대 압력에 대한 등급, 차단 임무에 대한 시트 확장에 따라 결정됩니다.

다음 패밀리에 속함: 게이트 밸브 패밀리

최종 업데이트: 2026-11

견적 요청

패밀리 사양

Nominal valve connection size	NPS 2"~12"(DN50~DN300）
Pressure class / nominal rating designation	ASME CLASS 300~2500（PN40~PN420）
Valve body material	Carbon steel, Stainless steel, Alloy steel, Duplex stainless steel
End connection types	RF, BW, RTJ
Operation / closure mode	Manual, Pneumatic, Electric, Hydraulic
Design standards	API 6D
selection seat ring life vs slab	Compared with a slab gate valve of the same size, an expanding gate design gives the full-bore pigging conduit together with longer seat-ring seal life, because the seat faces engage with the gate only near the end of travel rather than rubbing throughout the stroke.
selection torque tightened bidirectional seal	The two-segment gate is expanded against both seats by the stem/handwheel thrust, so the mechanical seal tightens as operating torque increases and does not depend on line pressure to energize it; this makes the shut-off bidirectional and relatively insensitive to pressure surges and vibration.
selection full bore pigging conduit	In the fully open position the gate segments retract into the body so the bore becomes a continuous cylindrical conduit, allowing pipeline pigs and scrapers to pass and keeping turbulence and pressure drop close to that of an equal length of pipe.
selection double block and bleed	In the closed position the expanded gate seals simultaneously against both the upstream and downstream seats, so the body cavity between the seats can be drained or vented, giving a double-block-and-bleed isolation function from a single valve.
selection seat faces shielded from flow	The seat rings are oriented to face outward so they contact the flow medium as little as possible and engage fully with the gate only at the end positions; this shielding of the sealing faces is a main reason expanding gates tolerate abrasive or debris-laden service better than wedge gates.
selection cam locks segments during travel	A cam/guide mechanism holds the two gate segments against expansion while the gate is mid-stroke: the assembly slides without seat friction during travel and expands only at the fully open or fully closed position, which protects the seats from wear during partial stroking.
selection stem thrust not pressure energized	Bubble-tight isolation is achieved upstream and downstream simultaneously purely through stem thrust on the wedge slopes; no line-pressure energizing of the seal is required, so sealing performance is maintained at low or zero differential pressure.
selection temperature envelope	Standard material trim covers roughly -29 C to 190 C service with low-temperature and extended-temperature options beyond that; published envelopes differ widely between makers, so the applicable temperature window must be confirmed against the specific body/seat materials rather than the generic design.
failure thermal cavity overpressure liquid service	With the gate expanded and both seats sealed, trapped liquid in the body cavity can build dangerous overpressure when the line warms up; valves for liquid service must therefore be fitted with a functioning thermal cavity relief system, and any needle valves in that circuit must be open before operation.
failure debris damages seat inserts	Scale, welding slag and other foreign material left in the pipeline are a leading cause of seat leakage at commissioning: debris packed between the gate segments and seat faces scratches the inserts. The line must be flushed and the valve cycled clean before it is put into service.
failure pre install cycle check for obstruction	Before installation the valve should be fully opened and closed once; if any abnormal resistance is felt, operation must stop and the stem and bore inspected for obstructions, since debris jammed in the gate-segment mechanism is easier to remove on the bench than in-line.
failure gland overtightening raises torque	Over-compressing the stem packing shortens packing life and noticeably raises operating torque, which matters for an expanding gate where the handwheel already works against wedge friction; the gland should be tightened only enough to stop leakage.
installation upright orientation recommended	The standard mounting is on a horizontal line with the stem vertical and the handwheel above the valve centerline, which keeps the gate-segment assembly aligned and supported; some makers qualify other orientations, and horizontal-stem or vertical-line installations require special design or tooling.
installation secondary sealant injection ports	Two sealant/lubricant injection ports in the body mid-section allow an approved sealant to be injected to the seat-gate interface as an emergency secondary seal if the sealing surfaces are damaged and leaking; injection pressure is kept within about 300 psi above line pressure.
installation cavity bleed via bonnet vent	With the valve fully closed, body-cavity pressure can be vented through the bonnet vent fitting (operator standing clear of the vent), and bottom drain plugs allow flushed-out debris to be removed; this gives a routine way to prove cavity depressurization after double-block-and-bleed closure.
standards api 6d vs api 6a envelopes	Expanding gate valves are made to two distinct API frames: pipeline valves to API 6D (roughly NPS 2-36, ASME Class 300-2500) and wellhead valves to API 6A (smaller bores at 2000-15000 psi working pressures); a 6D valve is not interchangeable with a 6A valve of similar size.
standards leakage testing iso 5208 api6d	Acceptance leakage testing for API 6D expanding gate valves is specified against ISO 5208 leakage-rate classes (with API 6D setting the class requirements per service), in addition to the standard hydrostatic shell and seat tests.
standards design codes b16 34 face to face	Pressure-boundary dimensions follow ASME B16.34 for pressure-temperature ratings, with face-to-face to API 6D/ASME B16.10, butt-weld ends to ASME B16.25, and welded-end/adapting-flange dimensions to ASME B16.34/MSS SP-44.
special features	Bi-directional torque based mechanical seal, Gate assembly travels freely between the seal surfaces which reduces the wear risk and prolongs the valve service life
applications	High temperature and high pressure pipelines

범위·출처 비고

temperature envelope disagreement	Temperature envelope disagreement: one OEM states -29 to 190 C standard (low-temp option to -46 C) while another claims -196 to +649 C working temperature; the wide claim likely reflects special trims and must not be used as the generic envelope.
orientation guidance differs	Orientation guidance differs: one OEM IOM recommends upright installation (handwheel above centerline), another states vertical as designed but horizontal acceptable, and a third offers special horizontal-stem/vertical-line designs; present as upright preferred with other orientations per manufacturer qualification.
torque comparison tension	Torque comparison tension: one OEM claims lower operating torque than an equivalent slab gate while the expanding design also deliberately uses higher seating torque to mechanically expand the gate - the statements refer to different points in the stroke and must not be merged into a single torque claim.