A pig receiver is the trap that catches a pig at the end of its run and lets an operator remove it from the pipeline safely. This guide explains how a receiver works, how it differs from a launcher, the receiving sequence, and why the receiving barrel collects debris and liquids that make it a hazardous vessel.
Pig Receiver in one line: A pig receiver (receiving trap) is a barrel and pipework assembly at the downstream end of a piggable line that decelerates and captures an arriving pig. Product flow is routed through the receiver via a bypass so the pig is carried into the oversized barrel, where a pig signaler confirms arrival. The operator then isolates the trap, vents and drains it, and opens the closure to extract the pig along with any debris and liquids it has swept ahead of it.
A receiver mirrors a launcher but works in reverse. The barrel is an oversized section on the downstream side, joined to the pipeline through a reducer, with a quick-opening closure at the far end. A trap isolation valve separates the barrel from the mainline, and a mainline bypass valve lets flow be directed through the trap. As the pig approaches, the operator routes flow so that it carries the pig past the reducer and into the barrel.
A mechanical or magnetic pig signaler flags when the pig has passed into the trap. With the pig captured, the operator closes the trap valve to isolate the barrel from the pipeline, then vents gas and drains liquids through dedicated connections. Only after pressure and inventory are confirmed at zero is the closure opened and the pig removed.
The receiving barrel accumulates everything the pig pushed ahead of it: wax, scale, black powder, sludge, and slugs of liquid. That means the trap can hold hydrocarbon liquids, pyrophoric deposits, and hazardous gases such as H2S even after the gas is vented. Draining and gas-freeing the barrel before opening the closure is essential, and pressure-relieving interlocked closures prevent opening a still-pressurized trap.
In oil and gas, receivers sit at the downstream terminus of gathering lines, transmission pipelines, and offshore trunk lines - anywhere a launcher sends a pig. The collected debris is also useful intelligence: its volume and composition tell integrity engineers how much wax, water, or corrosion product the line is generating between runs.
A launcher pushes a pig into the line using a kicker line; a receiver catches the pig at the end of the run using a bypass that draws flow through the trap. The barrels look similar, but the launcher is on the upstream end and the receiver on the downstream end of a piggable line.
The barrel collects liquids, sludge, pyrophoric deposits, and hazardous gases the pig swept ahead of it, and it can retain line pressure. Opening the closure before venting, draining, and gas-freeing the trap risks a release, so interlocked closures and permit procedures are mandatory.
The amount and type of wax, water, scale, and corrosion product collected between pig runs indicates how the line is fouling and corroding. Integrity engineers use it to set cleaning frequency and to spot developing problems before they become failures.
Merobix reads your field devices into a cloud SCADA - the real thing behind these terms, live in days from any browser.