Description

What Is Pig Passage Indicator?

A pig passage indicator is a monitoring instrument that shows when a pig moves past a set point on a pipeline. Also called a pig signaler, pig signaller, or pig detector, it gives proof that a cleaning, batching, or inspection tool has left the launcher or reached the receiver. EMT installs these units at pig traps and mid-line points on crude, gas, water, and petrochemical systems. Operators also place them at section breaks to narrow the search area when a pig stalls. Our intrusive pig passage indicator uses a spring-loaded trigger on a flange, NPT, or welded branch that penetrates the bore. Non-intrusive types clamp to the pipe wall and sense the pig by magnetic, ultrasonic, or acoustic methods. Both detect foam pigs, steel-body pigs, spheres, and intelligent inspection tools across onshore and offshore lines. Accurate passage data protects the asset and shortens shutdowns.

What Are the Key Parameters?

Engineers size each indicator to line class, medium, and method. Our intrusive builds cover a 2-inch flange (ASME B16.5), NPT, or welded nipple, rated ANSI 150 through 2500 LB, for lines from 2 inches upward. The table lists core specifications we keep in stock. We also offer non-intrusive magnetic, ultrasonic, and acoustic units up to 60 inches. Trigger choices include bi-directional, bi-directional feather, and uni-directional. Indicator styles span a manual reset flag, a flag with electrical switch, and a digital display with switch. Wetted parts come in PTFE-coated A105N, 316L SS, duplex, or Inconel for sour service. Every order ships with a material certificate and a factory test report. Share your line size, pressure class, and signal type, and we confirm the exact build. Custom seals and exotic alloys keep severe-service jobs on one plan.

Parameter	Value
Mounting	2″ flange / NPT / welded nipple (ANSI 150-2500#)
Pressure rating	ANSI 150# to 2500# (boss to 10,000 psi / 69 MPa)
Temperature	-20 C to +120 C (special seals beyond)
Trigger types	Bi-directional / Bi-directional Feather / Uni-directional
Indicator types	Manual reset flag; flag + switch; digital + switch
Wetted parts	PTFE A105N / 316L SS / DSS F51 / Inconel 625
Protection	IP66, Exd II BT4, NACE MR0175
Switch output	DPDT / 2xSPDT, DC24V 3A-5A
Insert depth	Adjustable +/-10 mm to 20 mm
Non-intrusive range	Magnetic / ultrasonic / acoustic, up to 60″ pipe

How Does Pig Passage Indicator Work?

The indicator works through two detection paths. An intrusive unit sits on a branch and extends a spring-loaded trigger into the flow. When the pig passes, it pushes the trigger aside. The trigger rotates a flag from horizontal to upright as clear visual proof. Electrical versions send a dry-contact signal to the control room for remote alarms. A magnetic pig signaller senses the pig’s embedded magnets and logs passage without line pressure. Ultrasonic and acoustic units listen for the pig from outside the wall and confirm passage with no bore penetration. The operator resets the flag by hand before the next run. No dynamic seals touch the product in intrusive types, so leakage risk stays low. This supports reliable pig passage detection at every monitored point. Crews set the insert depth to match wall thickness, and feather triggers sense light pigs without false trips.

Why Choose Pig Passage Indicator?

Five reasons operators specify EMT’s pig passage indicator:

• Intrusive and non-intrusive options cover any line, medium, and access limit.
• A spring-loaded trigger confirms each pass with no dependence on line pressure.
• Manual reset flag and electrical output both link straight to SCADA alarms.
• IP66 and Exd II BT4 ratings suit Zone 1 hazardous pipeline areas.
• Adjustable insert depth matches detection to your exact wall thickness.

Bi-directional and feather triggers sense lighter pigs without false trips. Each unit meets NACE MR0175 and ships with a pressure-test certificate for traceability. Removable bodies with a DBB valve allow service under pressure, so crews swap units without a shutdown. We tune wetted materials to sour or corrosive service on request. Spare trigger kits keep multi-station pigging projects on one delivery plan. Field reports from each site feed our next design update, so the indicator keeps improving.

Who Is EMT and Why Trust Us?

From our Shenyang plant, EMT engineers and makes complete pigging and integrity systems, holding the ASME U Stamp for certified pressure-vessel production. In-house CNC centers, robotic welding cells, and a hydrostatic test bay govern quality from raw stock to shipment. We proof-test each pig passage indicator before dispatch and enclose a test certificate with every consignment for traceability. Operators, EPC contractors, and maintenance crews across 30-plus countries run our gear in the field. We schedule around tight shut-down windows and provide expedited delivery when the clock is tight. Our support engineers answer in English, Spanish, Russian, or Chinese within four working hours. Beyond pig indicators, we build QOC closures, corrosion monitoring systems, chemical injection quills, and cleaning pigs. We supply turnkey pigging packages from concept design through site commissioning. As one single-source partner, we deliver your entire pigging scope under a single quality standard.