PIG LAUNCHER /
RECEIVER SKIDS
Pipeline pigging for cleaning, inspection, and commissioning -- factory-assembled launcher and receiver skids built to your pipeline specification and operating pressure.
When and Why Pipelines Need to Be Pigged
Pipeline pigging is not optional maintenance -- for crude oil and gas pipelines in wax-forming or corrosive service, it is the operational practice that keeps pipelines flowing at design capacity and extends pipeline service life. A pig launcher and receiver are the permanent infrastructure that makes scheduled pigging possible without a pipeline shutdown.
Wax Removal in Crude Oil and Condensate Pipelines
High-wax crude oils deposit paraffin wax on pipeline walls as the oil cools below the wax appearance temperature. Wax deposition progressively reduces the effective pipeline diameter, increases friction losses, raises the back-pressure on the producing wells, and ultimately leads to pipeline blockage if not managed.
Regular pigging with foam, brush, or scraper pigs removes accumulated wax before it reaches critical thickness. A properly designed launcher and receiver with quick-opening closures makes this a routine operation -- measured in hours, not days.
Inline Inspection (Smart Pig) Launching and Receiving
Pipeline integrity management requires periodic in-line inspection (ILI) using intelligent pigs -- instrumented tools that travel through the pipeline measuring wall thickness or detecting geometry changes. Smart pigs are more demanding: they have defined length-to-diameter ratios that must fit within the barrel length; they require specific entry and exit velocities.
LINSON OIL designs launcher and receiver barrels with the barrel-to-barrel (B-B) length and diameter verified against the specific ILI tool dimensions specified by the pipeline operator.
Pipeline Commissioning -- Purging and Dewatering
Before a new pipeline is placed in service, the hydrotest water must be removed and the pipeline dried to prevent corrosion and water contamination of the first product batch. This is done by launching a series of pigs to push the water to the receiver end, followed by drying pigs and nitrogen purging.
LINSON OIL designs launcher and receiver skids that can handle the full sequence of commissioning pigs as well as the cleaning and inspection pigs required for ongoing operations.
Product Batching in Multi-Product Pipelines
Pipelines that carry multiple products (different crude grades, condensates, or refined products) in sequence use batching pigs to physically separate the products in the line. The pig acts as a plug between consecutive batches, reducing product contamination at the batch interface.
Batching pig launchers and receivers must accommodate the full range of pig types used on the pipeline -- including any specialty pigs used to achieve minimum interface contamination for high-value products.
LINSON OIL's pig launcher and receiver skids are pressure vessels under GB 150 / ASME VIII Div.1 and piping systems under ASME B31.3 / GB/T 20801 -- designed and fabricated under the same A2 pressure vessel license and GC2 piping license that covers all LINSON OIL pressure equipment.
Pig Trap Engineering -- What the Design Must Get Right
The Barrel -- Sizing for the Pig
The launcher and receiver barrel is an oversized pipe section -- larger in diameter than the mainline -- that provides clearance for the pig to be inserted and removed. The barrel diameter is typically one nominal pipe size larger than the mainline (e.g., a 10" launcher barrel for an 8" pipeline). The barrel length must accommodate the longest pig that will ever be used on the pipeline -- the barrel-to-barrel (B-B) length (from the mainline valve face to the closure face) must exceed the pig body length by a defined clearance margin.
The barrel is a pressure vessel designed to the same operating pressure as the pipeline. At a pig trap, the barrel is periodically exposed to full line pressure and then depressurised for pig access -- a cyclic loading condition that influences the fatigue design of the closure, closure sealing system, and barrel shell.
The Closure -- The Critical Safety Component
The closure is the access door at the end of the barrel. It must seal the barrel to full operating pressure when closed, open and close safely when the barrel is depressurised, prevent opening if the barrel is still pressurised (safety interlock), be operable by one person in field conditions, and seal reliably after many open/close cycles without leakage.
LINSON OIL supplies quick-opening closures (QOC) with davit-mounted swing-open operation as standard. The safety interlock on a QOC requires the bleed valve to be open (barrel vented to atmosphere) before the closure locking ring can be disengaged -- this is the primary protection against accidental opening of a pressurised barrel.
The Mainline Valve -- Full Bore Is Non-Negotiable
The valve connecting the barrel to the mainline must be a full-bore ball valve -- full port, with an internal diameter matching the mainline internal diameter exactly. Any restriction in the mainline valve would prevent pig passage and could damage the pig or cause it to become stuck in the valve bore. LINSON OIL specifies full-bore ball valves per API 6D with bore diameter verified against the pig's minimum passage diameter.
The Kicker Line -- Controlling Launch and Receive
For pig launching, the kicker line routes a portion of the upstream pipeline flow around the mainline valve and into the barrel behind the pig -- creating a differential pressure across the pig that launches it into the mainline. For pig receiving, the kicker line diverts flow around the mainline valve to slow the approaching pig -- controlling the impact velocity at the receiver closure and protecting both pig and closure from damage.
Pig Signaller / Passage Indicator
A pig signaller is installed on the mainline downstream of the launcher and upstream of the receiver. It detects the pig's passage by the mechanical deflection of a target plate and signals pig launch/arrival. LINSON OIL installs signallers as standard on both launcher and receiver skids, with local mechanical indication and -- where remote monitoring is specified -- an electrical signal output to the control system.
Drain and Vent Connections
Before the closure can be safely opened, the barrel must be depressurised and drained of any accumulated liquid. The vent connection removes gas pressure; the drain connection removes liquid. LINSON OIL sizes vent and drain connections per the barrel volume and target depressurisation/drain time specified by the client.
Engineering Specifications
| Parameter | Standard Range | Notes |
|---|---|---|
| Mainline Size | DN50 (2") - DN600 (24") | Larger on request |
| Barrel Diameter | One NPS larger than mainline (std) | Two NPS larger for large-bore pigs |
| Barrel Length (B-B) | Per pig spec + clearance margin | Verified against tool vendor min B-B |
| Design Pressure | 1.0 - 15.0 MPa (g) | Higher on request; high-pressure vessel license |
| Design Temperature | -20°C to +150°C | Extended range with material selection |
| Barrel Material | API 5L / ASTM A106 Gr.B / 316L SS | Per pipeline material and fluid |
| Corrosion Allowance | 2-3 mm | Per fluid and H₂S/CO₂ content |
| Closure Type | Quick-opening (davit, interlocked) | Threaded endcap for smaller sizes/lower pressure |
| Closure Seal | Elastomeric O-ring or T-seal | Rated for operating pressure and temperature |
| Mainline Valve | Full-bore ball valve, API 6D | ANSI 150# - 2500# per design pressure |
| Kicker Line Valve | Ball valve, manually or actuated | Sized per launch/receive velocity control |
| Pig Signaller | Mechanical target type (standard) | Electronic for remote monitoring |
| Design Code (Barrel) | GB 150 / ASME VIII Div.1 | ASME U-stamp for export |
| Design Code (Piping) | ASME B31.3 / GB/T 20801 | GC2 licensed |
| Skid Frame | Carbon steel; primer + finish coat | |
| Lifting | 4-point lift | Load calculation provided |
| FAT | Valve, closure, signaller, pressure test | Client witness available |
Pig Launcher vs. Receiver -- Key Differences
| Feature | Pig Launcher | Pig Receiver |
|---|---|---|
| Barrel orientation | Angled entry into mainline (15°-30° recommended) | Angled exit from mainline |
| Barrel length | Shorter -- pig body length + margin | Longer -- includes deceleration zone |
| Kicker line function | Creates differential pressure to launch pig | Slows arriving pig; reduces impact |
| Closure operation | Opened to insert pig; closed before launch | Opened to remove pig after arrival |
| Signaller location | Downstream of launcher mainline valve | Upstream of receiver mainline valve |
| Typical accessories | Pig loading / handling aid | Pig collection cradle or tray |
Standard Supply & Customization Options
Standard Skid Package (Included)
- Barrel vessel (per GB 150 / ASME VIII Div.1; design pressure, temperature, and material per specification)
- Reducer (mainline to barrel diameter transition)
- Quick-opening closure with davit arm and safety interlock (pressure-dependent locking)
- Mainline full-bore ball valve (API 6D; manual or gear-operated per size)
- Trap (isolation) valve at closure end
- Kicker line assembly with isolation valve and check valve
- Vent connection with isolation valve (routed to flare or safe vent)
- Drain connection with isolation valve (routed to drain or pig receiver sump)
- Pig signaller (mechanical, target type) with local indicator
- Pressure gauge and pressure transmitter nozzle
- Skid structural frame with lifting pads and equipment mounting
- Surface treatment: barrel and piping per service; structural steel primer + finish coat
- Factory pressure test at 1.25× design pressure
- Barrel-to-barrel (B-B) length verified and documented against pig specification
- As-built drawings, valve data sheets, closure maintenance manual, quality dossier
OEM / ODM Customization Options
| Option | Application |
|---|---|
| Electronic pig signaller with remote output | 4-20 mA or discrete signal to DCS / SCADA; confirms pig passage without manual inspection |
| Actuated mainline and kicker line valves | Remote-operated launching and receiving from control room |
| Combined launcher/receiver (LR) | Single skid with dual-function capability; space and cost saving for smaller pipelines |
| Smart pig (ILI tool) accommodation | Extended B-B length; wider barrel tolerance; smooth bore requirements per tool vendor spec |
| High-pressure barrel design (> 10 MPa) | High-pressure gas pipelines; subsea tie-in systems |
| Sour service material upgrade | NACE MR0175 / ISO 15156; wet H₂S resistant materials and welds |
| Low-temperature material (-46°C or -60°C) | Arctic or cold-climate pipeline service |
| Stainless steel barrel and piping | Highly corrosive fluid; offshore produced water or gas with high CO₂ |
| Pig handling equipment | Loading arm, handling tray, or pig dolly integrated onto skid for heavy pigs |
| Foam / gel pig receiver sump | Drainage sump and connection for liquid-removing or gel pigs |
| ASME U-stamp | International / export project requirements |
| DNV / BV / ABS certification | Offshore and marine pipeline installations |
| ATEX / IECEx instrumentation | Zone 1 / Zone 2 area classification |
| Dual-barrel configuration | Allows one barrel to be loaded while the other is in service |
Pressure Vessel Licensed. Pipeline Code Compliant. Closure Safety Interlocked.
Certifications
- › Special Equipment Manufacturing License (A2 + High-Pressure) -- barrel vessel
- › Special Equipment Manufacturing License (GC2) -- all trap piping
- › GB 150 / ASME VIII Div.1 -- barrel design
- › ASME B31.3 / GB/T 20801 -- piping design
- › API 6D -- mainline and kicker line valves
- › ISO 9001:2015 Quality Management
- › ISO 3834-2 Welding Quality Management
- › CNAS Accredited Laboratory (RT, UT, MT, PT)
- › ASME U-stamp available
- › SGS / BV / DNV third-party inspection
- › Sinopec & CNPC HSE Certified Supplier
QA Process
Barrel-to-Barrel (B-B) Dimension Verification
Before fabrication is released, the B-B length is verified against the pig specification documents provided by the client or tool vendor. For smart pig traps, the tool vendor's minimum B-B length and bore diameter requirements are confirmed against the design drawing. Any discrepancy is flagged and resolved before welding begins.
Material Traceability
Barrel shell, reducer, and nozzle materials procured with mill certificates. For sour service or API 5L pipe specification materials, full traceability from heat number through fabrication and delivery. 3.1 certificates on request for international projects.
Welding and NDT
WPS and PQR maintained per GB/T 19869 / ASME IX for all barrel and piping joint types. CNAS-accredited in-house NDT: RT on barrel longitudinal and circumferential seams; UT on weld joints where RT is impractical; MT/PT on nozzle welds and closure attachment welds.
Closure Safety Interlock Verification
The quick-opening closure safety interlock is physically tested: with the bleed valve closed (barrel pressurised simulation), verify that the locking ring cannot be disengaged; with the bleed valve open, verify that the locking ring disengages correctly. Interlock function test documented in FAT report.
Hydrostatic Pressure Test
Barrel hydrotested at 1.25× design pressure per GB 150 / ASME VIII Div.1. Closure sealed and included in the pressure test -- this tests the closure seal under full test pressure, not just the barrel shell. Witnessed testing available.
Valve Operation and Full-Bore Verification
Mainline valve stroked full open and closed; torque or operating force documented. Full-bore check: straight bar passed through the fully open mainline valve bore to verify no obstruction. For smart pig traps, bore gauge passed through the full barrel assembly per tool vendor requirements.
Export Preparation
Closure face protected; nozzles blanked; barrel interior preserved; export crating applied. Full quality dossier shipped with skid.
Pig Traps -- Certified and Delivered for Pipeline Operations Across China's Upstream Industry.
Upstream Pipeline Pigging Infrastructure -- Multiple Projects
Pig launchers and receivers are standard infrastructure items on crude oil and gas pipelines of any significant length. LINSON OIL has supplied pig trap skids -- standalone and as part of larger gathering station and pipeline terminal packages -- for upstream pipeline systems across Shandong, Xinjiang, and other producing regions. The traps are designed to accommodate the full range of pigs used in China's domestic upstream operations: foam pigs, disc pigs, brush pigs, and ILI tools.
Sinopec & CNPC -- HSE Certified Supplier
Pipeline equipment -- including pig traps -- supplied to Sinopec and CNPC systems must pass incoming inspection under the NOC HSE supplier qualification framework. LINSON OIL's sustained certification in both systems reflects a delivery record across pipeline equipment categories including pig trap infrastructure.
International Project Pipeline Equipment
For international projects -- including the Congo Brazzaville Jiarou Oilfield associated gas system -- pipeline infrastructure including pigging stations was included in the facility design. LINSON OIL has the export documentation, shipping, and international delivery experience to deliver pipeline equipment to international project sites.
View Congo Brazzaville Project DetailsWarranty Terms
Standard: 2 years from commissioning or 26 months from shipment -- covering barrel vessel integrity, piping integrity, valve mechanical function, and closure sealing system. Closure seals (O-rings or T-seals) are consumables subject to wear based on operating cycles and fluid service -- seal replacement intervals and spare seal specifications are documented in the closure maintenance manual at delivery.
Long-term partners: up to 2.5 years, with priority access to replacement closure seals, signaller targets, and valve seat kits.
After-Sales Support
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Closure seal replacement guidance: step-by-step procedure in maintenance manual; seal dimensions and material specification for direct procurement from seal supplier.
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Valve maintenance: torque specification and seat replacement instructions for mainline and kicker line valves.
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Smart pig accommodation review: if a new ILI tool with different dimensions is to be used, LINSON OIL can review the existing B-B length and bore against the new tool requirements and advise on any modifications needed.
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Pigging procedure consultation: operating sequence documentation for launcher and receiver operations, including isolation, depressurisation, pig loading, launch, receipt, and pig removal steps.
Pipeline Size, Design Pressure, Pig Type.
We'll Design the Trap.
Pig launcher and receiver sizing requires four inputs: mainline diameter, design pressure, pig types to be used (including any ILI tool specifications), and area classification. For smart pig traps, provide the tool vendor's minimum B-B length and bore gauge diameter. Send us these parameters and our engineers will confirm the barrel configuration and deliver a preliminary design within 1-2 business days.
Free Engineering Resource
Submit your pipeline parameters and receive:
- ✓ Preliminary barrel sizing: barrel diameter, recommended B-B length, closure type recommendation
- ✓ Smart pig accommodation check: confirmation if standard or extended barrel is required
- ✓ Design code and certification roadmap
*Reviewed by LINSON OIL mechanical engineers. Response typically within 1-2 business days.*
LINSON OIL -- A2 Vessel + GC2 Piping + API 6D Valves | ASME U-stamp Available | CNAS Accredited NDT | Sinopec & CNPC HSE Certified