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エキスパンディングゲートバルブ
エキスパンディングゲートバルブは機械的に密封します。閉止時にゲート組立体が両シートへ拡張し、管路圧力に依存しない両方向・トルク式シールを得ます。移動中は組立体が密封面間を自由に動くため摩耗が減り寿命が延びます。高温・高圧パイプラインで確密な締切が要求される場面の選択肢です。範囲はNPS 2"～12"（DN50～DN300）、ASME Class 300～2500（PN40～PN420）、ボディは炭素鋼・ステンレス鋼・合金鋼・デュプレックスステンレス鋼、端接続はRF・BW・RTJ、操作は手動・空圧・電動・油圧、設計はAPI 6Dです。性能を支えるのは構造詳細です。シートリングは外向きで端位置のみ噛み合い（カム保持のゲートセグメントは無摩擦で移動し、中間ストロークでもシートを摩耗しません）、密封はステム推力のみで締め付けられ、差圧ゼロでも圧力補助なしで両方向・気泡レベル密閉、全開ボアはパイプ同等の圧力損失でピグを通過させる連続流路です。閉止時は両シートが同時に密封されるため、間のキャビティを排水・ベントでき、DBB遮断に使えます。典型的な故障経路は、液体内のキャビティ熱過圧（キャビティリリーフを設けニードル弁を開放）、試運転ゴミによるシート挿入部の傷（起動前にラインをフラッシュ・サイクル）、くさび式と同様に重いトルクをさらに膨らませるグランド過締めです。水平配管にステムを上向きで据え付け、据付前に全開/全閉のサイクル試験でゲート機構の引っかかりを確認し、中間部の2つの注入ポート（管路圧力+約300psi以内）は緊急二次シールと位置付け、閉止後のキャビティ減圧確認にはボンネットベントを使います。APIの2つの枠組みに注意。パイプライン弁はAPI 6D+ISO 5208漏れクラス（面間API 6D/ASME B16.10、突合せ溶接B16.25、定格B16.34）、小型ウェルヘッド弁はAPI 6Aで、互換性はありません。選定はラインに対する口径帯、ピーク圧力に対するクラス、締切用途に対するシート仕様で決まります。
次のファミリーに属する： ゲートバルブ ファミリー
最終更新： 2026-11
ファミリー仕様
| 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 |
範囲と出所の注記
| 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. |
注文と書類
書類
お問い合わせの際に必要な書類セットをお知らせください——この型番仕様の典型的な項目（材質証明書、記載の検査規格に基づく試験報告書、寸法図）は、見積時に確認のうえ供給されます。
お見積り
見積可能なお問い合わせには次の事項をご記入ください：呼び径と圧力レーティング、ボディ・シート材質の希望、接続方式、操作方式、温度を含む使用流体。このページの典型値はベンチマーク参考範囲です。拘束力のある値は見積時に確定します。
サンプルと供給
供給条件、発注数量、納期は注文ごとに協議します——お問い合わせの際に納入国と希望スケジュールをお知らせください。
保管と輸送
バルブはシート・シールを紫外線、オゾン、変形から保護して保管し、据付まで端面保護カバーを取り付けたままにしてください。エラストマーまたは PTFE シートの仕様では、屋外での長期保管を避けてください——シート材料は直射日光と凍結条件で最も劣化が早くなります。
よくある質問
エキスパンディングゲートバルブの見積依頼には何を含めるべきですか？
適用規格とクラス、呼びサイズ、ボディおよびシート材、使用媒体と温度、納入先——欠落している項目は見積の過程で確認します。
エキスパンディングゲートバルブにはどのサイズと圧力等級がありますか？
このバルブの検証済みサイズと圧力等級範囲はまだ本ページに掲載されていません——お客様の使用条件に適したサイズと圧力等級は見積の過程でご提案し、確認します。使用条件を問い合わせに添えていただければ、選定結果を見積書に記載します。
エキスパンディングゲートバルブにはどのボディ材質がありますか？
このバルブの検証済みボディ材質範囲はまだ本ページに掲載されていません——お客様の使用条件に適したボディ材質は見積の過程でご提案し、確認します。使用条件を問い合わせに添えていただければ、選定結果を見積書に記載します。
エキスパンディングゲートバルブ の見積依頼
こちらからご要望をご提出ください——見積に直結するお問い合わせには、適用規格とクラス、口径、材質、流体、温度、納入先をご記入ください.
お客様の情報の取り扱いについては、プライバシー通知をご覧ください。