Pig Signaller

1. Product Overview

A pig passage indicator (also called a pig signaller) is a monitoring device installed directly on the pipeline. Its main function is to confirm that a pig has passed a specific location or has arrived at the pig receiver. This device allows operators to track the pig’s movement inside the closed pipeline, avoiding guesswork or losing track of the pig in long-distance pipelines.

2. Standard Technical Specifications

3. Why Pigging Systems Need Pig Signallers

Pigging operations involve risks, and pig signallers are essential safety tools:

• Status confirmation: Ensures technicians know when the pig has left the launcher or arrived at the receiver.
• Blockage detection: Multiple signallers along the pipeline help locate where a pig may be stuck if one signaller triggers but the next does not.
• Automation: Electronic signallers can send signals to SCADA systems, enabling automated pigging operations.

4. Key Features

• Sensitive activation mechanism: Internal trigger arm (ball or curved type) requires only slight force from the pig to activate immediately.
• Leak-proof design: Special sealing system ensures no fuel leakage even under high pressure.
• Easy visibility: Mechanical flags are brightly colored (red or reflective yellow) for clear visual detection from a distance.
• No flow obstruction: Trigger arm retracts or rests against the pipe wall after pig passage, avoiding pressure drop or flow restriction.

5. Practical Applications

• At launchers and receivers: Installed just after the launcher outlet valve and before the receiver inlet valve to confirm start and end of pigging.
• At pipeline branches: Positioned at T-junctions or crossroads to ensure pigs follow the intended route.
• Offshore/onshore pipelines: Installed at both ends of critical segments for safety monitoring.
• Chemical & food industries: Stainless steel versions used to signal when pigs have cleared old product from pipelines before CIP cleaning.