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三用閥（triple duty）

三用閥將三項泵出口功能合併於一個 1/4 迴轉閥體內——標定流量平衡、防撞擊逆止與確定關斷——節省機房空間、安裝工時以及三閥歧管的額外法蘭接點。廠商範圍為 DN65-DN300 鑄鐵，直通與角式結構，端接法蘭、螺紋或溝槽；引用結構為 1-1/2 至 16 in，額定自分銷商目錄管路的 175 psi WOG 至最強參考的 375 psi / 300 F，其中滴漏級密封以額定的 150% 測試，且閥體可在現場由直通轉為角式。平衡依標定銘牌設定，記憶止動銷在關斷後恢復設定位置；軟閥座彈簧輔助閥盤抑制抖動，凸輪式落座使部分結構在金屬閥座上也能嚴密密封。該型式專用於泵出口側：應離泵足夠遠以免逆止組件抖動，保持閥桿/手柄不朝下，並接受自全開位置約關閉 15% 的正確運行狀態。同一裝置在泵配件產品線中以多個商標出現；在流量測量精度關鍵的場合，三用閥是補充而非取代專用平衡閥。

屬於逆止閥系列

最後更新： 2026-11

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系列規格

Nominal valve connection size	DN65 to DN300
Valve body material	Cast Iron
Valve body material	Cast Iron, Bronze Seat
Disc Materials	A536 Nickel Plated Ductile Iron, Bronze B62
Seat material	A536 Nickel Plated Ductile Iron, EPDM O-Ring
cover flange materials	Cast Iron
Stem material	SS410
Packing Materials	Non-Asbestos
spring material	300 Series Stainless Steel
function definition	A triple-duty valve replaces three valves with one body - shut-off, check and calibrated flow balancing - which is what removes the footprint of a three-valve pump-discharge manifold in the mechanical room.
closing mechanics	Closing is a two-stage quarter-turn action: the plug rotates to block the downstream port so pressure equalizes around the clapper, then the plug cams against the clapper backside for the final tight fit - the maker recommends turning to normal tight fit then bumping the plug lightly.
backflow protection range	Backflow protection holds across a wide range of system-balance settings because the check element is spring-assisted, not dependent on a single operating point.
size end envelope oem	The referenced OEM line spans 1-1/2 through 16 inch in flanged or threaded ends (globe style); the tenant band DN65-DN300 sits inside this envelope.
drip tight isolation test	Isolation quality is testable, not assumed: the referenced execution is designed and tested for drip-tight shut-off at 150 percent of maximum working pressure.
convertible body	Straight- versus angle-pattern is a site decision on convertible executions: the body can be changed in the field, replacing a separate 90-degree elbow on the pump discharge.
pressure temp envelope	The referenced execution is rated to 375 psi maximum working pressure and 300 F (150 C), sized 1-1/4 inch NPT through 12 inch flanged.
throttle design	Throttling uses a plug-and-disc design rather than a globe-style trim, which keeps the balance function and the shut-off seat on the same closure member.
dominant line envelope	Distributor listings for the dominant straight/angle-pattern line show cast iron bodies with flanged, NPT and grooved ends, all rated 175 psi WOG - a materially lower ceiling than the 375 psi reference execution.
calibrated balance memory	Balancing is calibrated against a nameplate scale so system flow can be set to a number, and the memory button returns the valve to its set position after shut-off.
anti chatter seat	The soft seat design damps valve chatter, protecting the trim from the noise and seat damage that chatter produces.
non slam staged parallel	The non-slam check element prevents backflow and gravity circulation in staged and parallel pumping, protecting the idle pump from reverse rotation.
cam seating metal seats	The disc approaches the seat with a cam action that produces high seating pressure, so tight shut-off is achievable even with metal seats and discs, not only soft seats.
memory stop function	Most triple-duty valves carry a pre-set balance and a memory stop so the balancing position can be restored exactly after shut-off; many models add calibrated markings, test ports and manufacturer performance data for field flow setting.
vs dedicated balancing valve	A triple-duty valve balances, but it is not a dedicated balancing valve: where flow-measurement accuracy or specialized balancing control is critical, the designer should verify whether the combined valve is appropriate or a dedicated balancing valve is preferred.
installation distance chatter	Placement matters: mounted too close to the pump discharge the check assembly chatters, wearing springs and the flapper prematurely and distorting gauge differential readings.
orientation limit	Orientation is restricted: vertical or horizontal mounting is acceptable, but the stem or handle must not point downward or upside down, and the valve cannot be left fully open - it must be closed about 15 percent to operate correctly.
naming map	The same device appears under different trade names across pump-accessory lines, so cross-line comparison should start from the shared three-function definition of shut-off plus check plus calibrated balancing.
maintainability	Routine maintenance is mainly leak checks at the packing nut and bonnet gasket; stem packing, disc and nameplate are replaceable internals on most executions.
bg catalog mwp	The straight-pattern catalog line is rated 175 PSIG (1,207 kPa) maximum working pressure.
bg cv table straight	Cv at 100% stem rise on the straight-pattern line spans 83-3,000 m3/h (flowmeter reference) and 77-3,225 m3/h (pressure-drop reference) across 2-14 in sizes.
bg cv 4in reference	A 4 in execution of the combined valve carries a pressure-drop Cv of 320 in catalog reference data.
bg commissioning dp	Gauge readings across the valve support commissioning: they indicate how to trim the pump impeller or set the maximum speed of the variable-frequency drive.
bg pt ports	Integrated pressure-temperature test ports allow direct measurement for flow verification.
bg ashrae balancing	Balancing practice reference: hydronic systems are proportionally balanced to minimize throttling losses first, then the pump impeller is trimmed or pump speed adjusted to meet design flow.
bg disc soft seat	One catalog execution pairs a brass disc with a soft seat to provide positive shut-off together with the non-slam check function.
peer model designation example	Flanged 2-1/2 in straight-pattern units are designated 3DS-2-1/2S under catalog number 132122.
peer spring disc check	The check element is an integrated spring-loaded disc; flow-optimized internal geometry limits pressure drop while preventing reverse flow and water hammer.
peer tsvn designation	The globe-style quarter-turn combined valve line from one maker carries designation TSVN, offered flanged or threaded in sizes 1-1/2 through 16 in.
Maximum working pressure	8 Bar
max operating temperature	120C
disc material	Brass, EPDM Seal Insert
Stem material	Stainless Steel
packing material	Teflon-Graphite, Asbestos-free
gasket material	Asbestos-free
readout valve	Brass, NPT insert, Check Valve

範圍與來源備註

pressure envelope	Pressure envelope: the B&G distributor listings cap at 175 psi WOG while the Pentair Aurora 1040 reference reaches 375 psi / 300 F - the type has no single industry pressure ceiling; class follows the specific execution.
size envelope	Size envelope: tenant band DN65-DN300 (2.5-12 in) sits inside the Wheatley 1-1/2-16 in globe-style line but above the Pentair 1-1/4 in NPT low end - boundaries are execution-specific.
fully open prohibition	Fully-open prohibition: the Liberty guidance that the valve must be closed ~15% from full open to operate correctly is a balancing-function note, not a general check-valve rule - conflicts with how plain check valves are described elsewhere on the site.
seat material split	Seat material split: B&G listings emphasize soft (spring-assisted, anti-chatter) seats while the Liberty cam-action note supports metal-seat tight shut-off - both exist, but they are different execution choices, not one industry standard.