Pig Launcher: Definition and Purpose in Oil & Gas Pipelines
A pig launcher is a pressure-rated vessel that enables operators to introduce a pig (Pipeline Inspection Gauge) into a pipeline without interrupting flow. Structurally, it resembles a cylindrical barrel fitted with a closure system, isolation valves, and auxiliary connections. It is usually installed at the beginning of a pipeline section, working together with a pig receiver at the opposite end.
Why Pig Launchers are Important
- Pipeline Cleaning – Pigs are inserted through launchers to scrape out wax, rust, scale, and other deposits that can reduce pipeline efficiency.
- Internal Inspection – Smart pigs, deployed via launchers, use advanced sensors to measure wall thickness, detect cracks, corrosion, or other integrity issues.
- Fluid Separation – In multiproduct pipelines, pigs prevent cross-contamination by separating different transported fluids.
- Flow Assurance – By maintaining a clean pipeline, pigging reduces pressure drops and ensures smooth product transport.
- Safety & Reliability – Routine pigging through launchers identifies weak points early and helps avoid leaks or catastrophic failures
The Pig launcher is used for launching metallic pigs / spheres for cleaning the debris which accumulates inside the pipeline over a period of time. Pig receivers on other ends receives the pig.
The main instrumentation related to the pig launcher and pipeline is the Shutdown Valves, Motor operated valves etc which isolate the production header and launcher from the pipeline section.
There will be pressure transmitters to monitor the pressure in the pipeline, local pressure gauges, and a Pig indicator for indicating the passage of a pig / sphere launched. A Pressure Relief Valve will also be there to protect the pig launcher from over pressure.
Pipeline pigging is a key part of maintaining the integrity of pipeline system. Pipelines required pigging at start and end of life.
Pig Launcher
What is a Pig Receiver and Why is it Used?
A pig receiver is a special unit installed at the end of a pipeline. Its job is to safely collect and remove a pig (Pipeline Inspection Gauge) after it has finished traveling through the pipeline. You can think of it as the exit station for pigs, while the pig launcher is the entry station.
Why Pig Receivers are Important
- Safe Collection – The receiver makes sure the pig can be taken out without any danger from pipeline pressure.
- Removes Dirt and Deposits – Any wax, scale, or debris pushed by the pig gets collected inside the receiver, keeping the pipeline clean.
- Handles Smart Pigs – For intelligent pigs that record inspection data, the receiver allows easy and safe removal so the information can be downloaded.
- Keeps Operations Smooth – With a proper receiver, pigging can be done without cutting or opening the pipeline itself.
- Safety First – It allows venting, draining, and pressure release before operators open the closure, preventing accidents.
Pipelines are normally pigged for
- Commissioning and decommissioning
- Cleaning or wax removal
- Inventory management, by sweeping out liquids, batching products etc.
- Corrosion and scale control
- Inspection of the pipeline
- Isolation and special operation
- Inline Inspection
- Pipeline Cleaning
- Batching
Different Types of Pigs Used in Pig Traps by Pig launcher / Receiver
Pig traps are devices used to send and receive pigs inside pipelines. These pigs perform different tasks like cleaning, separating products or inspecting the pipeline. Below are the main types explained in simple terms:
1. Foam Pigs
- Purpose: Lightweight pigs used for basic cleaning, drying, and removing water or dust.
- Example: After pressure testing a new oil pipeline with water, foam pigs are passed through to remove the leftover water before gas or oil flows.
2. Steel (Metal) Pigs
- Purpose: Strong pigs designed for heavy cleaning tasks such as removing wax, sludge, or solid deposits.
- Example: In crude oil pipelines, especially those carrying heavy oil, steel pigs scrape out thick wax layers that could block the flow.
3. Gel Pigs
- Purpose: Soft and flexible pigs used for separating different products or carrying cleaning chemicals.
- Example: In pipelines that transport petrol, diesel, and kerosene one after another, gel pigs are used to keep the products from mixing.
4. Brush Pigs
- Purpose: Equipped with brushes to remove hard scale, rust, and other stubborn deposits.
- Example: Old natural gas pipelines often run brush pigs before inspection so the pipe walls are clean and free from rust.
5. Magnetic Pigs
- Purpose: Contain magnets to collect loose metal pieces from inside the pipeline.
- Example: After new pipelines are welded, magnetic pigs sweep up metal fragments like welding rods or slag that might damage pumps and valves.
6. Intelligent (Smart) Pigs
- Purpose: High-tech pigs fitted with sensors, electronics, and data systems to inspect pipelines.
- Example: Offshore oil and gas companies use smart pigs to detect cracks, corrosion, or thinning walls in undersea pipelines to prevent leaks and accidents.
Conventional Pig Traps vs Intelligent Pig Traps – Key Differences Explained
Pipeline pigging is a critical process for both pipeline maintenance and pipeline integrity management. Depending on the operation, companies rely on two main types of pig traps: conventional pig traps for cleaning and batching, and intelligent pig traps (or ILI traps) for inspection with smart pigs. Understanding the differences helps operators choose the right system for their specific pipeline requirements.
What Are Conventional Pig Traps?
Conventional pig traps are the standard pig launching and receiving units used in routine pipeline pigging.
- Purpose: Designed to clean pipelines by removing wax, scale, sand, and other deposits, as well as to separate products in multi-product pipelines.
- Pig Types: Foam pigs, cup pigs, disc pigs, and scraper pigs are the most common.
- Design Features: Simple construction consisting of a launcher or receiver barrel with a closure system.
- Size & Length: Compact design, usually 1.5–3 meters long, depending on the pipe diameter. The trap barrel is only slightly longer than the pig itself.
- Operation: Allows quick insertion and removal, making it ideal for frequent pigging operations.
- Limitations: Cannot handle advanced inspection tools or delicate electronic components.
What Are Intelligent Pig Traps?
Intelligent pig traps are built for In-Line Inspection (ILI) tools, also known as smart pigs. These are highly advanced devices equipped with sensors that provide detailed diagnostic data about pipeline conditions.
- Purpose: Used for pipeline integrity assessment — detecting corrosion, cracks, dents, metal loss, and other structural issues.
- Pig Types: Smart pigs with technologies such as Magnetic Flux Leakage (MFL), Ultrasonic Testing (UT), Electromagnetic Acoustic Transducer (EMAT), and geometry pigs.
- Design Features: Smooth internal finish to prevent damage to sensitive electronics, plus rollers, guides, and lifting points to safely handle the inspection tool.
- Size & Length: Much longer than conventional traps, typically 3–8 meters or more depending on diameter and pig type. Must accommodate the entire inspection unit, which can be several modules long.
- Operation: Requires specialized handling and maintenance due to the complexity and cost of ILI tools.
- Limitations: Higher capital investment and longer setup times compared to standard traps.
| Aspect | Conventional Pig Traps | Intelligent Pig Traps (ILI Traps) |
|---|---|---|
| Primary Use | Cleaning, batching, product separation | Integrity inspections and data collection |
| Pig Types | Foam pigs, cup pigs, disc pigs, scraper pigs | Smart pigs with sensors (MFL, UT, EMAT, geometry) |
| Trap Length | Short (1.5–3 m) | Long (3–8 m or more) |
| Internal Finish | Rugged, standard | Smooth, sensor-friendly |
| Complexity | Simple, low-maintenance design | Advanced with rollers, guides, lifting aids |
| Data Output | None | Full diagnostic data (corrosion, cracks, wall loss) |
| Cost | Lower | Higher |
| Frequency of Use | Frequent (routine pigging) | Periodic (planned inspections) |
Final Takeaway
- Conventional pig traps are short, simple, and cost-effective, making them the go-to choice for pipeline cleaning and batching operations.
- Intelligent pig traps are longer, smoother and engineered to handle ILI smart pigs, ensuring safe passage for inspection tools that deliver crucial diagnostic data.
Pig Launcher and Receiver major barrel and minor barrel length dimensions
Dimensions [mm] for non-intelligent pig trap. It provides the standard dimensions of pig launcher and receiver units based on pipeline nominal diameter.
Standard Pig Launcher & Receiver Dimensions for non-intelligent pig trap
This table shows typical sizes used for pig launchers and receivers in oil and gas pipelines. The values are given for different nominal pipe diameters (ΦA). Dimensions like L1, L2, Drain, Equalization line, and ΦB help in designing and installing pig traps safely.
| Nominal Diameter ΦA | L₁ – Launcher | L₂ | L₁ – Receiver | ΦB | Φ Drain |
|---|---|---|---|---|---|
| 80 (3”) | 1000 | 1000 | 1150 | 80 (3”) | 50 (2”) |
| 100 (4”) | 1000 | 1000 | 1400 | 80 (3”) | 50 (2”) |
| 150 (6”) | 1100 | 1100 | 1500 | 100 (4”) | 50 (2”) |
| 200 (8”) | 1350 | 1350 | 1700 | 150 (6”) | 50 (2”) |
| 250 (10”) | 1600 | 1600 | 1700 | 200 (8”) | 80 (3”) |
| 300 (12”) | 1800 | 1600 | 1800 | 200 (8”) | 80 (3”) |
| 350 (14”) | 1800 | 1600 | 1800 | 200 (8”) | 80 (3”) |
| 400 (16”) | 2000 | 1600 | 2000 | 250 (10”) | 80 (3”) |
| 450 (18”) | 2000 | 1600 | 2000 | 300 (12”) | 80 (3”) |
| 500 (20”) | 2000 | 1600 | 2000 | 300 (12”) | 100 (4”) |
Standard Pig Launcher & Receiver Dimensions for Intelligent Pig Traps
This table shows typical sizes used for pig launchers and receivers in oil and gas pipelines. The values are given for different nominal pipe diameters (ΦA). Dimensions like L1, L2, Drain, Equalization line, and ΦB help in designing and installing pig traps safely.
| Nominal Diameter ΦA | L1 – Launcher | L2 | L1 – Receiver | ΦB | Φ Drain | Φ Equalization/ Balancing Line |
|---|---|---|---|---|---|---|
| 100 (4”) | 2350 | 2400 | 2350 | 80 (3”) | 50 (2”) | 25 (1”) |
| 150 (6”) | 2000 | 1950 | 2000 | 100 (4”) | 50 (2”) | 25 (1”) |
| 200 (8”) | 3050 | 3000 | 3050 | 150 (6”) | 50 (2”) | 50 (2”) |
| 250 (10”) | 2900 | 2750 | 2900 | 150 (6”) | 80 (3”) | 50 (2”) |
| 300 (12”) | 3600 | 3400 | 3600 | 200 (8”) | 80 (3”) | 50 (2”) |
| 350 (14”) | 3700 | 3450 | 3700 | 200 (8”) | 80 (3”) | 50 (2”) |
| 400 (16”) | 3300 | 3050 | 3300 | 250 (10”) | 100 (4”) | 50 (2”) |
| 450 (18”) | 3600 | 3250 | 3600 | 300 (12”) | 100 (3”) | 50 (2”) |
| 500 (20”) | 2000 | 1650 | 3350 | 300 (12”) | 100 (4”) | 50 (2”) |
| 550 (22”) | 2100 | 1650 | 3350 | 350 (14”) | 100 (4”) | 50 (2”) |
| 600 (24”) | 2000 | 1550 | 3700 | 400 (16”) | 100 (4”) | 50 (2”) |
| 650 (26”) | 2100 | 1550 | 3700 | 400 (16”) | 100 (4”) | 50 (2”) |
| 700 (28”) | 3600 | 2950 | 4100 | 450 (18”) | 100 (4”) | 50 (2”) |
| 750 (30”) | 3100 | 2450 | 4900 | 500 (20”) | 100 (4”) | 50 (2”) |
| 800 (32”) | 2600 | 1850 | 4300 | 500 (20”) | 100 (4”) | 50 (2”) |
| 850 (34”) | 2100 | 2300 | 4400 | 550 (22”) | 150 (6”) | 50 (2”) |
| 900 (36”) | 3200 | 2700 | 4850 | 600 (24”) | 150 (6”) | 50 (2”) |
| 950 (38”) | 3200 | 2730 | 4850 | 600 (24”) | 150 (6”) | 50 (2”) |
| 1000 (40”) | 4200 | 3250 | 5150 | 650 (26”) | 150 (6”) | 50 (2”) |
| 1050 (42”) | 4200 | 3250 | 5450 | 650 (26”) | 150 (6”) | 50 (2”) |
Pig Signallers for Pig launcher and Receivers
A Pig Signaller is a device installed on pipelines to confirm the passage of a pig or cleaning sphere at a specific point. Think of it as a checkpoint indicator that provides either a visual or electronic signal when the pig has moved past.
Purpose
In long-distance pipelines, pigs are launched for cleaning, inspection or product separation. Operators need real-time confirmation of the pig’s location to ensure smooth operations. Pig signallers provide this feedback without interrupting the process.
Working Principle
- The unit consists of a sealed housing containing a magnet and spring-loaded trigger.
- When the pig passes through the line, it pushes the conical trigger, causing the internal magnet to move.
- This action releases the external flag or electrical sensor, clearly indicating that the pig has crossed the point.
- The internal trigger resets automatically, while the external flag can be reset manually by the operator.
Types of Pig Signallers
- Mechanical / Visual – uses a drop flag for indication.
- Electrical / Electronic – sends signals to a control system.
- Combination Units – offer both visual and remote monitoring.
Quick Opening Closures Pig launcher and Receivers
A Quick Opening Closure is a specially designed device fitted to pipelines and pressure vessels that provides rapid entry and sealing without the need for multiple bolts. Unlike conventional closures, which can take considerable time and effort to open, a QOC can typically be operated in under half a minute.
Purpose Quick Opening Closures
QOCs are mainly used where frequent access is required, such as in pig launchers and receivers, inspection points or vessels that need regular cleaning or product changeover. Their design allows operators to open and reseal equipment safely and quickly, minimizing downtime.
How a Quick Opening Closures Works
- Depressurization – Before opening, the built-in vent plug is removed to confirm that no internal pressure remains.
- Unlocking – A short rotation of the handle (around 20–30°) disengages the locking mechanism.
- Access – The door can then be swung open for full access to the vessel or pipeline.
- Re-sealing – To close, the door is repositioned, rotated back into lock, and sealed.
- Most designs include multi-level safety interlocks to prevent opening if pressure is still present, ensuring operator protection.
- Advantages of Quick Opening Closures
- Fast operation – open and close within seconds
- High safety – interlocks stop accidental opening under pressure
- Low maintenance – simple sealing system, fewer moving parts
- Versatile – can be adapted for subsea use with ROVs
- Cost-effective – saves man-hours compared to bolted closures
- Available quickly – designed for efficient manufacturing and short lead times
Common Applications
- Pigging systems (launchers and receivers)
- Oil, gas and petrochemical pipelines
- Pressure vessels needing routine access
- Offshore and subsea pigging operations
Working area requirement near Pig Launchers and Receivers?
Pig launchers and receivers are special equipment used in pipelines to put pigs inside the pipe or take them out. Since these units are large and involve manual work, a clear space around them is always required.
Here’s why this working area is important:
For Handling Pigs Easily
- Pigs can be heavy or long, especially smart pigs.
- Workers need free space to insert them into the launcher or remove them from the receiver.
For Opening and Closing the Door
- These units have a closure (door) that must be opened wide.
- Without enough space, this becomes difficult and unsafe.
For Maintenance and Cleaning
- Launchers and receivers require regular checks, valve cleaning, and inspection.
- Extra space makes this work safe and comfortable.
For Safety During Emergencies
- In case of gas leaks or sudden release of pressure, workers should quickly move away.
- A clear area gives them room to escape safely.
For Using Lifting Tools
- Sometimes cranes, chain blocks, or lifting devices are needed to handle pigs.
- Without a proper working area, such tools cannot be used.
To Meet Safety Standards
- Pipeline safety codes (like ASME, API) recommend safe access around pigging equipment.
- Providing space ensures the system follows these standards.
Space requirement for Pig Launcher and receiver
| ΦA – Nominal Diameter | Access “X” (axial) | Access “Y” (lateral) |
|---|---|---|
| 100–350 mm (4–14″) | L1 + 1000 mm | 1000 mm |
| 400–750 mm (16–30″) | L1 + 1000 mm | 1400 mm |
| 800–1100 mm (32–42″) | L1 + 1000 mm | 1750 mm |
What the terms mean
- ΦA (Nominal Diameter): Line/trap size class.
- L1: Trap barrel length (from closure to reducer/tee).
- Access “X”: Straight, in-line clearance in front of the closure for tool handling.
- Access “Y”: Side-to-side working room for lifting, staging, and maneuvering.
Quick rules
- Axial clearance is always the trap barrel length plus 1 meter (L1 + 1000 mm).
- Lateral clearance grows with diameter to accommodate longer, modular ILI tools and lifting gear.
- Maintain these envelopes free of obstructions (handrails, cabling, skids) to ensure safe, damage-free handling
Pig Launcher & Receiver – Complete FAQs in Simple Words
1) What is the function of a pig receiver?
- A pig receiver is like a “parking bay” at the end of the pipeline where the pig safely stops. Its job is to:
- Catch the pig after it travels through the line.
- Release pressure, gas, or liquid so it can be opened safely.
- Collect dust, wax, rust, or other waste brought by the pig.
- Allow removal of data from smart pigs used for inspection.
In short, it makes sure the pig finishes its job without damaging the pipeline or causing safety risks.
2) Who makes pig launchers and receivers?
Pig launchers and receivers are usually made by companies that design and build pipeline equipment. Some are large international manufacturers, while others are local workshops certified to make pressure vessels. They are built according to standards like ASME codes or regional oil & gas rules. The final unit can also be supplied by EPC (Engineering, Procurement, Construction) contractors who provide a complete package with valves, instruments, and safety systems.
3) What does PIG stand for in pipeline?
The word PIG is commonly taken as Pipeline Inspection Gauge. Some people also call it Pipeline Intervention Gadget. Long ago, when the first pigs made a squealing sound while moving inside the pipe, workers started calling them “pigs,” and the name stuck.
4) How long is the pig launcher and receiver?
The size of a pig launcher or receiver depends on the pipe diameter, pressure, and the type of pig. On average:
- Small sizes (around 4 inches) may be about 2 meters long.
- Medium sizes (around 12 inches) may be about 3.5 meters long.
- Larger ones (24 inches or more) can reach 4 to 5 meters long.
- Intelligent pigs (used for inspection) usually need extra barrel length because they carry sensors and electronics.
Extra space in front and on the sides is also required so the pig can be safely loaded and removed.
5) Pig launcher and receiver – what do they do?
- Pig Launcher: Works like a starting station. The pig is placed inside, the system is pressurized, and the flow pushes the pig into the pipeline.
- Pig Receiver: Works like a finish line. It collects the pig at the end of its run, releases pressure, drains fluids, and makes the pig safe to remove.
6) What is the difference between a pig launcher and a pig receiver?
- A launcher sends the pig into the line.
- A receiver collects the pig after its journey.
- The launcher focuses on inserting and pushing the pig forward, while the receiver focuses on catching and unloading it.
- The launcher usually sees less debris, while the receiver often handles dirt, wax and liquids.
7) How does a pig launcher work?
Here’s the step-by-step working
- The pig is placed inside the launcher barrel.
- The closure is sealed tightly.
- Pressure is balanced between the launcher and the pipeline.
- Flow is directed behind the pig using valves and a kicker line.
- The pressure pushes the pig forward into the main pipeline.
- Once launched, the launcher is isolated, vented and drained so it’s safe to open again.