Product Range
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Gauge Block Nonoflange DBB（紧凑型仪表双截断泄放阀）
1/2" - 2" (DN15 - DN50)
Gauge Block Nonoflange SBB（仪表块式 NanoFlange SBB）
1/2" - 2" (DN15 - DN50)
固定球式双截断双排放（DBB）阀门
2" - 24" (DN50 - DN600)
双截断与排放（DBB）
Quick Specs 2" - 20" (DN50 - DN500) Class 150 - 600 API 6D, API 607, ASME B16.34, ISO 15848 A216 WCB, A351 CF8M, A182 F51 PTFE, Nylon, PEEK, metal-to-metal (Stellite 6) Flanged end connections (RF/RTJ), bolted bonnet, double block & bleed in single body, manual or actuated operation Flanged Connections——Where the Pipeline Specification Calls for Bolted End Connections The flanged DBB valve serves the same isolation function as the trunnion DBB——two independent blocking seats with a verified bleed cavity between them——but with flanged end connections to the pipeline instead of butt-weld. Flanged connections (raised face or ring-type joint per ASME B16.5) are the standard pipeline connection method for Class 150 through Class 600 in many facility specifications——particularly on process piping systems where maintenance accessibility requires bolted connections that can be disassembled without cutting and re-welding the pipe. A butt-weld DBB valve (like the FLOWKS all-welded DBB series) permanently joins the valve to the pipeline——removal requires cutting the weld and re-welding a replacement. A flanged DBB valve unbolted from the pipeline flanges——four bolts per flange (on smaller sizes) or dozens on larger sizes, but the principle is the same: unbolt, remove, replace, re-bolt. No welding. No hot work permit. No radiographic inspection of replacement welds. That bolted-connection accessibility is the primary reason facilities specify flanged DBB valves on Class 150-600 piping——the maintenance logistics of bolted connections are simpler, faster, and cheaper than welded connections on the pressure classes where flanged joints are structurally adequate. Above Class 600, butt-weld connections become the standard specification because flanged joints at Class 900 and above require heavier bolting, larger gasket surfaces, and higher bolt tensioning loads that push the flanged-connection maintenance complexity beyond practical limits for many installations. The FLOWKS flanged DBB covers Class 150 through Class 600——the pressure range where flanged connections serve the majority of process piping installations and where the bolted-connection maintenance advantage is most valuable. Bolted Bonnet——Maintenance Access Without Removing the Valve from the Pipeline The bonnet (the valve body section that contains the stem, packing, and the upper trunnion bearing) attaches to the body through a bolted bonnet-to-body connection——bolted, not welded. That bolted bonnet design provides maintenance access to the stem packing, the upper trunnion bearing, and the ball-and-seat assembly without removing the entire valve from the pipeline flanges. The maintenance procedure: unbolt the bonnet, lift the bonnet assembly (stem, ball upper pin, packing) out of the body, access the seat rings and ball for inspection or replacement, re-install the bonnet with new gasket, re-bolt, re-torque. The pipeline flanges stay bolted——the valve body stays connected to the pipeline throughout the maintenance operation. That in-line maintenance capability is the same principle that FLOWKS top-entry ball valves use for buried and welded pipeline service——the difference is that the flanged DBB's bolted bonnet serves flanged-connection installations where the pipeline flanges themselves are the primary disassembly point, and the bonnet bolts are the secondary access point for internal trim maintenance. The bonnet-to-body gasket is a critical sealing element——it's the pressure boundary between the body cavity (exposed to pipeline pressure) and the bonnet cavity (exposed to packing and stem). The gasket specification matches the process media and temperature conditions: spiral-wound gaskets (stainless winding with graphite or PTFE filler) for general process service, metal-ring gaskets for high-temperature and fire-safe applications where spiral-wound gaskets would degrade under sustained thermal loading. The gasket gets replaced every time the bonnet gets unbolted——gaskets are one-time sealing elements, not reusable. That replacement requirement is standard maintenance practice across bolted-bonnet valve designs——you don't re-use a gasket on a pressure boundary, you install a new one every time the joint gets re-assembled. Double Block and Bleed——Same Functional Architecture, Flanged Installation Package The DBB isolation architecture inside the flanged body is identical to the trunnion DBB: two independent spring-loaded seats pressing against the trunnion-mounted ball from opposite sides, with a bleed cavity between them that vents through a designated port on the body. The upstream seat blocks process pressure from the active pipeline section. The downstream seat blocks pressure toward the isolated section. The bleed cavity verifies both seats simultaneously——zero pressure at the bleed confirms both blocking boundaries are holding. The functional behavior is the same regardless of the connection type (flanged or butt-weld): the seats seal, the bleed verifies, the isolation is double and independent. The difference between the flanged DBB and the butt-weld DBB is entirely in the installation interface——flanged ends for bolted pipeline connection with maintenance accessibility, versus butt-weld ends for permanent pipeline integration with maximum structural integrity and minimum external leak paths. Both configurations deliver the same DBB isolation performance. The choice between them is driven by the facility's piping specification (does the line use flanged or welded connections at this size and pressure class?), maintenance philosophy (is in-line removal a requirement or is permanent installation preferred?), and the specific application's structural and regulatory requirements. FAQ Flanged DBB: bolted end connections (RF/RTJ flanges)——removable from the pipeline by unbolting without cutting pipe. Butt-weld DBB: welded end connections——permanently joined to the pipeline, removal requires cutting the weld. Same DBB isolation function inside the body. Flanged for maintenance accessibility on Class 150-600 piping. Butt-weld for permanent installation and minimum external leak paths on Class 900+ piping or buried service. Above Class 600, flanged connections require heavier bolting, larger gasket surfaces, and higher bolt tensioning loads that make flanged maintenance less practical than butt-weld. Butt-weld connections are the standard specification for Class 900-1500 piping——the structural integrity and leak-path elimination of welded joints outweighs the maintenance accessibility advantage of flanged connections at those pressure ratings. FLOWKS offers butt-weld and all-welded DBB configurations for Class 900-1500 applications. In-line maintenance access to the stem packing, trunnion bearings, and seat/ball assembly without removing the valve from the pipeline flanges. Unbolt the bonnet, lift it out, service the internals, re-bolt with a new gasket. The pipeline stays connected throughout——no hot work, no cutting, no re-welding. That accessibility is the maintenance advantage of bolted-bonnet design over welded-bonnet design. Yes——API 607 with metal-to-metal seats (Stellite 6). Flanged connections with RTJ gaskets maintain sealing through fire exposure alongside the valve body's metal seating. On flammable service pipelines, fire-safe certification is mandatory regardless of the connection type——flanged or welded, the seating system has to hold through fire. 1/2" or 1" flanged or threaded connection on the body——vented to atmosphere or closed drain depending on the process media. Hazardous media (H₂S, hydrocarbon, VOC) requires closed drain capture. Non-hazardous utility service vents to atmosphere through a needle valve. The bleed port size scales with the valve bore——larger bores use larger bleed ports to accommodate higher potential bleed flow rates under seat-failure conditions.
法兰-螺纹连接针型 DBB 阀
Quick Specs 1/2" - 1" (DN15 - DN25) up to 10,000 psi (Class 150 - 2500 equivalent) API 6D, API 607, ASME B16.34, ISO 15848 A182 F316, A182 F51, A182 F53 PTFE, PEEK, metal-to-metal (Stellite 6) Flanged process-side connection + threaded (NPT) instrument-side connection, needle-type DBB with compact body, double block & bleed with single bleed port Flange on One End, Screw on the Other——Where the Pipeline Is Flanged but the Instrument Is Threaded Process piping at the instrument connection point often has a flanged isolation valve on the pipeline side and a threaded (NPT) connection at the gauge or transmitter side——the pipeline specification calls for flanged connections above 1" bore for structural integrity and maintenance accessibility, but the instrument connection (gauge, transmitter, pressure switch) is almost always 1/2" NPT threaded because instruments don't have flanged process connections. That mismatch——flanged on one side, threaded on the other——is exactly what this valve addresses. The process-side (upstream) connection is a flanged end (RF or RTJ per ASME B16.5) that bolts directly to the pipeline flange. The instrument-side (downstream) connection is a threaded NPT port that the gauge or transmitter threads onto directly. Two blocking seats and a bleed cavity sit between the flanged upstream connection and the threaded downstream connection——the DBB isolation function spans the entire flow path from flanged pipeline interface to threaded instrument interface, with no additional fittings, adapters, or interconnection leak paths between them. Without this flange-to-screw configuration, the installer has to cobble together a flanged isolation valve, a reducing fitting (flange-to-thread adapter), and a separate bleed valve——three components with two interconnection points (flanged-to-adapter, adapter-to-instrument) that are both potential external leak paths. Each interconnection adds a gasket or thread seal that has to be maintained independently. The flange-to-screw needle-type DBB eliminates both interconnection points——the flanged end bolts directly to the pipeline, the threaded end accepts the instrument directly, and the DBB isolation is inside the single body between them. No adapter. No extra fitting. No interconnection leak paths. One valve body spans the entire connection mismatch. Needle-Type——Compact Body for High-Pressure Instrumentation Taps The needle-type designation means the blocking seats are needle-valve trim rather than ball-valve trim——a tapered needle plug that seats into a matching cone-shaped seat ring, rather than a rotating ball that seals against flat or contoured seat rings. Needle trim has two practical advantages at small bore sizes and high pressures: First: the needle-and-cone seating geometry seals progressively——the needle seats deeper into the cone as closing force increases, creating a line-contact seal that tightens with additional stem torque. That progressive seating behavior gives needle-type valves a mechanical advantage at high pressures where ball-valve seats (which rely on surface-to-surface contact at a defined seat geometry) can struggle to maintain bubble-tight shutoff at pressures above Class 1500. The needle's tapered geometry creates a wedging effect——the more closing torque you apply, the tighter the needle wedges into the cone, and the seal gets progressively tighter rather than reaching a limit defined by the seat's elastic deformation. Second: the needle trim's compact geometry fits inside a body that's smaller than a ball-valve body at the same bore size——the needle assembly (stem, tapered plug, seat cone) occupies less internal volume than a ball assembly (ball, two seat rings, trunnion pins) at 1/2" bore. That compact geometry keeps the overall body dimensions shorter and lighter——critical for instrumentation installations where space allocation at the pipeline tap is limited, and where the weight on the flanged connection has to stay within the flange's structural capacity. The two blocking seats in the needle-type DBB are two independent needle-valve assemblies——one upstream (process-side) needle and one downstream (instrument-side) needle, each with its own stem, seat cone, and operating handle. The bleed port sits between the two needle seats——a third, smaller needle valve that vents the cavity between the two blocking needles. Three stems, three handles, one body. Each needle operates independently——close the upstream needle first, open the bleed needle to verify zero, then close the downstream needle. The sequence is the same as any DBB operation, but the seating mechanism is needle-and-cone rather than ball-and-ring. Two Needles and a Bleed——Independent Sealing, Independent Verification The upstream needle blocks process pressure from the flanged pipeline connection. The downstream needle blocks any pressure that might leak past the upstream needle from reaching the threaded instrument connection. The bleed needle vents the cavity between the two blocking needles to atmosphere or closed drain. Same DBB verification logic: close both blocking needles, open the bleed needle, check for zero pressure at the bleed——zero confirms both needles are holding. Process pressure at the bleed reveals an upstream needle failure. Pressure at the instrument connection reveals a downstream needle failure. The three-stem architecture makes the isolation status directly visible and independently operable——no need for a single actuator that closes both seats simultaneously (that's the ball-valve DBB approach), each needle gets closed and verified individually by the technician performing the isolation procedure. That individual operation capability is particularly valuable on high-pressure instrumentation taps where the closing sequence matters: the upstream needle gets closed first (isolating the process side), then the bleed gets opened (venting any residual pressure in the cavity), then the downstream needle gets closed (isolating the instrument side). The sequence can't be shortcut——each step depends on the verification from the previous step. Three separate stems make the sequence explicit and unambiguous——you can't accidentally close both blocking needles and skip the bleed verification because the three handles physically separate the three operations. High Pressure Capability——Needle Geometry Handles What Ball Geometry Can't at Small Bore The needle-and-cone seating geometry's progressive wedging action enables sealing at pressures where ball-valve seat surface contact reaches its mechanical limit. FLOWKS flange-to-screw needle-type DBB valves handle pressures up to 10,000 psi at 1/2" bore——the needle's tapered wedging seal maintains bubble-tight shutoff at those pressures because additional stem torque drives the needle deeper into the seat cone, creating progressively tighter contact rather than relying on elastic deformation of a flat seat surface. At Class 2500 and above (6000+ psi), ball-valve seating geometry at 1/2" bore requires extremely precise seat machining and high closure force to achieve Class VI——the needle's progressive wedging provides the same shutoff class with less machining precision requirement and more forgiving closure torque behavior. The body materials (A182 F316, F51, F53 forged alloys) handle the internal pressure at small bore dimensions where the wall thickness-to-bore ratio provides substantial structural margin at 10,000 psi. FAQ Seating mechanism. Needle-type: tapered needle plug seats into a cone-shaped seat ring——progressive wedging seal that tightens with additional stem torque. Ball-type: rotating ball seals against flat or contoured seat rings——surface-to-surface contact at a defined geometry. Needle-type handles higher pressures (up to 10,000 psi) at small bore sizes because the progressive wedging seal maintains tight shutoff where ball seating reaches its mechanical limit. Ball-type provides faster operation (90° quarter-turn vs. multiple stem turns) and is standard at larger bore sizes. Because process pipelines use flanged connections above 1" bore, but instruments (gauges, transmitters) use 1/2" NPT threaded connections. The flange-to-screw body spans that connection mismatch without requiring separate adapters——the flanged end bolts to the pipeline, the threaded end accepts the instrument, and the DBB isolation is inside the single body between them. Up to 10,000 psi on needle-type configurations with forged body materials (A182 F316, F51, F53). The needle-and-cone seating geometry's progressive wedging maintains tight shutoff at pressures where ball-valve seating at small bore sizes becomes marginal. For lower pressure applications (Class 150-600), ball-type DBB configurations are also available with flanged connections on both ends. Sequential DBB procedure: close the upstream (process-side) blocking needle——open the bleed needle and verify zero pressure at the bleed——close the downstream (instrument-side) blocking needle. The three separate stems make each step explicit and independently verifiable. You can't shortcut the sequence——each handle physically separates each operation, forcing the correct verification sequence. Yes——API 607 with metal-to-metal seating (Stellite 6 needle and cone). PTFE and PEEK seats don't survive fire exposure; metal seating maintains isolation through fire. On flammable gas and liquid instrument taps, fire-safe metal seating is mandatory regardless of the blocking mechanism type (needle or ball).
DBB 采样针阀
Quick Specs 1/4" - 1/2" (DN8 - DN15) up to 10,000 psi / Class 150 - 2500 equivalent API 6D, ISO 15848, NACE MR0175 (sour service configurations) A182 F316, A182 F51, A182 F53, Monel (NACE sour service) PTFE, PEEK, metal-to-metal (Stellite 6) Sampling needle valve with DBB isolation, compact body, threaded connections (NPT/BSP), sample port with double block protection Sampling from Live Process Lines——and Why the Sample Tap Needs DBB Protection A sampling valve extracts a small volume of process fluid from a live pipeline for laboratory analysis, quality verification, or regulatory compliance testing——the sample has to be representative (same composition, same pressure, same temperature as the main process stream), and the extraction has to be safe (the technician drawing the sample shouldn't get exposed to the full pipeline pressure, and the pipeline shouldn't lose containment through the sample tap). A simple single-block sampling valve provides one isolation boundary——when the valve is closed, the sample port is isolated from the pipeline. But that isolation is single-point: if the single seat leaks, pipeline pressure reaches the sample port and the sample container simultaneously——the technician gets hit with live process pressure while handling a sample bottle that's supposed to be at atmospheric pressure. On hydrocarbon, chemical, and sour gas sampling applications where the process media is flammable, toxic, or high-pressure, that single-point isolation failure is a safety incident——not just a sample contamination issue. FLOWKS sampling DBB needle valves provide double block and bleed isolation at the sample connection point——two independent needle-valve blocking seats with a bleed cavity between them, in a compact body that mounts directly at the pipeline sample tap. The upstream needle blocks pipeline pressure from the bleed cavity. The downstream needle blocks any pressure leaking past the upstream needle from reaching the sample port. The bleed cavity between the two needles vents to atmosphere or closed drain——zero pressure at the bleed confirms both blocking needles are holding before the sample port gets opened for sample extraction. The DBB architecture provides the same verified isolation logic at the sample tap that it provides at gauge and transmitter isolation points: you verify isolation through the bleed before you open the downstream side to atmosphere. On process sampling, that verification step is critical because the technician is about to open a sample container that's designed for atmospheric pressure——you don't expose an atmospheric-pressure sample bottle to even a trace amount of live pipeline pressure without verifying that the isolation is intact. Needle Trim——The Right Seating Mechanism for Small-Bore Sample Extraction Sample extraction volumes are small——a few milliliters to a few hundred milliliters, drawn through a 1/4" or 1/2" bore sampling port. The bore size is small because the sample volume is small and the extraction rate needs to be controlled precisely (fast sample draw pulls non-representative fluid; slow, controlled draw gives representative composition). Needle trim at 1/4"-1/2" bore provides the flow control precision that sampling requires——the tapered needle plug modulates the flow area incrementally as the stem rotates, giving the technician fine control over the extraction rate rather than an on/off open-or-closed binary. That modulation capability is built into the needle geometry——the needle doesn't just open and close, it throttles at partial positions where the flow area between the needle tip and the seat cone is precisely controlled by the stem rotation angle. For the DBB blocking seats (upstream and downstream), the same needle geometry provides progressive wedging sealing——tighter shutoff with additional stem torque, same as the flange-to-screw needle-type DBB. For the sampling extraction port (the downstream connection where the sample container attaches), the needle's throttling capability gives controlled extraction rate management——the technician doesn't open the sample port fully and let the process media rush into the container at pipeline velocity. Instead, the needle is opened incrementally, the sample flows at a controlled rate, the container fills slowly and steadily, and the composition stays representative because the extraction rate doesn't create turbulence or preferential-phase separation in the sample stream. Sample Extraction Procedure——DBB Verification Before Opening to Atmosphere The sampling procedure with a DBB needle valve follows a defined sequence that the three-stem architecture enforces physically: Close both blocking needles (upstream and downstream)——the sample port is fully isolated from the pipeline. Open the bleed needle——vent any residual pressure in the cavity between the two blocking needles. Check for zero pressure at the bleed. Zero confirms both blocking needles are holding. If bleed shows zero: proceed with sample extraction. Attach the sample container to the sample port connection. Open the downstream (instrument-side) blocking needle incrementally——controlled flow into the sample container. Close the downstream needle when the sample volume is collected. Close the bleed needle. The sample container is at atmospheric pressure and contains a representative process sample. If bleed shows live pressure: do NOT proceed. The upstream blocking needle is leaking——the isolation is compromised. The bleed port has revealed the failure before the sample port gets opened. Stop, report, and replace or repair the upstream seat before attempting sample extraction. That sequence can't be shortcut——the three separate handles physically separate each step, and the bleed verification between blocking and extraction forces the technician to confirm isolation before exposing the sample container to any potential process pressure. On toxic and flammable media sampling, that sequence is the safety protocol——not a recommendation, not a best practice, but the required procedure that regulatory frameworks and company safety standards mandate for process sampling from live pipelines. NACE MR0175 Sour Service——Sampling from H₂S-Containing Process Streams Sour gas and sour crude sampling (process streams containing H₂S at concentrations above the NACE MR0175 threshold) requires materials that resist sulfide stress cracking——the hydrogen sulfide environment attacks standard stainless steels at the points where stress concentration and microstructural susceptibility coincide (thread roots, seat contact zones, stem-to-body penetration points). FLOWKS sampling DBB needle valves are available in NACE MR0175-compliant configurations——body materials specified per the NACE requirements for the specific H₂S concentration, pH, and temperature conditions of the process stream (Monel for severe sour service, Inconel for high-temperature sour service, NACE-compliant F316 for moderate sour conditions where the standard alloy meets the hardness and heat-treatment requirements). The seat and trim materials are also specified per NACE——Stellite 6 hard-facing on the needle and seat cone surfaces is NACE-compliant and provides the metal-to-metal sealing durability that sour service demands (PTFE and PEEK are chemically compatible with H₂S, but metal seating is preferred for the mechanical durability under the repeated cycling that sampling valves experience). Sour service sampling is inherently more dangerous than non-sour sampling——H₂S exposure thresholds are low (10 ppm for 8-hour exposure, 100 ppm for 15-minute exposure, 300 ppm IDLH), and the sampling procedure puts the technician in close proximity to the sample port where any leak or isolation failure directly exposes them to the process stream. The DBB verification step (bleed-check before opening the sample port) is even more critical on sour service——the consequence of isolation failure isn't just a contaminated sample, it's an acute toxic exposure. NACE-compliant materials and DBB isolation architecture combine to make sour service sampling as safe as the valve design can achieve——but the procedure discipline (sequence adherence, bleed verification, no shortcuts) is the human factor that the valve design supports but can't replace. FAQ Application context and downstream connection. Gauge block DBB: instrument isolation——the downstream connection mates to a gauge or transmitter that stays permanently installed on the valve. Sampling DBB: sample extraction——the downstream connection is a sample port where the technician attaches a temporary sample container for extraction, then removes it after the sample is collected. Same DBB isolation architecture (two blocking seats + bleed cavity), but the downstream side serves a different function——permanent instrument connection on gauge block, temporary sample extraction port on sampling valve. Throttling capability and bore size. Sampling requires controlled extraction rate——the sample flows into the container slowly and steadily, not at pipeline velocity. Needle trim throttles at partial positions, giving the technician fine control over the extraction rate. Ball trim is on/off——full flow when open, no flow when closed, no modulation between. At 1/4"-1/2" bore where sampling operates, needle trim also provides better shutoff at high pressures than ball trim——the progressive wedging seal maintains tight closure where ball seating at micro-bore sizes is mechanically marginal. Body, trim, and seat materials specified to resist sulfide stress cracking in H₂S-containing environments. Monel body for severe sour service. NACE-compliant heat-treated F316 for moderate sour conditions. Stellite 6 trim for metal-to-metal seating that's NACE-compliant and durable under repeated cycling. NACE compliance isn't optional on sour service——it's the material specification requirement that prevents catastrophic failure (sulfide stress cracking) in the H₂S environment. Close both blocking needles, open the bleed needle, check for zero pressure at the bleed port. Zero confirms both needles are holding——safe to proceed with sample extraction. Live pressure at the bleed reveals upstream needle failure——don't proceed, don't open the sample port, don't expose the sample container to process pressure. The bleed check takes seconds and it's the safety gate between isolation verification and sample extraction. Yes——with appropriate body and trim materials (A182 F316L or Inconel for cryogenic temperatures) and extended bonnet designs that move the stem packing away from the cryogenic body temperature. LNG sampling, liquid nitrogen sampling, and other cryogenic process streams require material specifications and bonnet configurations that maintain mechanical properties and packing functionality at temperatures down to -196°C. The DBB isolation architecture and needle trim throttling capability apply at cryogenic temperatures with the correct material and design adaptations.
Technical Overview
Double block and bleed valves give you two independent sealing boundaries with a verified vent cavity between them. That sounds redundant until you've stood next to a pressure gauge on a 1500-psi hydrocarbon line and watched a single isolation seat weep process fluid toward the instrument connection. One seat can leak. One seat can fail. DBB eliminates that risk by requiring both an upstream and a downstream seat to hold simultaneously, with the bleed cavity between them vented to atmosphere or closed drain so you can visually confirm both seats are sealing before opening the instrument side. FLOWKS manufactures gauge block, flange, trunnion, and needle-type DBB configurations—from compact 1/2" instrument isolation valves through full-bore pipeline DBB units. Gauge block DBBs mount directly at instrument taps with nonoflange or flanged connections. Flange and trunnion DBBs isolate pipeline sections for maintenance, inspection, and pressure verification. Sampling DBB needle valves add a sample port between the two blocking seats, allowing fluid extraction without breaking isolation. Every DBB configuration shares the same functional principle: two seats, one bleed, verified zero-pressure proof that both boundaries hold before you proceed.
FLOWKS double block and bleed (DBB) valves provide verified dual isolation with a vented cavity between two independent seating boundaries. The upstream seat blocks process pressure; the downstream seat protects the instrument or downstream line; the bleed cavity between them vents to atmosphere or closed drain, giving visual confirmation that both seats are holding before any downstream work begins. Gauge block nonoflange DBB valves thread directly onto instrument taps—1/2" through 2", Class 150–1500, compact installation without flange bolting or gasket alignment. Gauge block SBB (single block and bleed) valves provide one blocking seat plus a bleed vent for applications where dual isolation isn't mandated. Flange DBB valves bolt into pipeline flanged connections for larger-diameter isolation. Trunnion DBB valves integrate the double block and bleed function into a trunnion-mounted ball valve body for full-bore pipeline service. Flange-to-screw needle-type DBB valves combine flanged process connections with threaded instrument connections, bridging between piping standards. Sampling DBB needle valves add a sample extraction port within the bleed cavity, allowing fluid collection without breaking either isolation boundary. FLOWKS DBB valves meet API 6D requirements for double isolation, with ISO 15848 fugitive emission certification available. Seat options include PTFE, PEEK, and metal-to-metal (Stellite 6) for chemical compatibility and temperature range matching.
Product Downloads
Industries Using DBB 阀门
See how DBB 阀门 are applied across different industrial sectors.
Oil & Gas
Upstream, midstream and downstream valve solutions meeting API 6D, API 607 fire-safe requirements. From wellhead to refinery, FLOWKS provides reliable valve solutions for the most demanding oil and gas applications.
LNG
Cryogenic valves engineered for liquefied natural gas processing and transportation. FLOWKS cryogenic service valves are tested to -196°C per BS 6364.
Refining
Heavy-duty valves designed for the extreme conditions of petroleum refining. FLOWKS valves handle high temperatures, corrosive media, and erosive service in refineries globally.
Looking for More Solutions?
Discover our range of products built for your industry's challenges.
Ball Valves
FLOWKS offers floating ball valve, trunnion mounted ball valve and top entry ball valve for oil & gas, petrochemical and power generation. Designed per API 6D, API 608 and ASME B16.34.
Gate Valves
FLOWKS gate valves for isolation service in piping systems. Flexible wedge, solid wedge, slab and expanding gate designs per API 600, API 602 and ASME B16.34.
Globe Valves
FLOWKS globe valves for throttling and isolation. Standard, angle, Y-pattern and bellows seal configurations per API 602 and BS 1868.
Check Valves
FLOWKS check valves prevent reverse flow. Dual plate, swing, tilting disc and lift check designs per API 594 and BS 1868.