Pig passage indicators, such as the SN2-TQZ model, are essential tools in pipeline maintenance and monitoring, designed to detect the presence and passage of pigs through pipeline systems. These devices are crucial for ensuring the operational efficiency and integrity of pipelines. Particularly in industries where fluid transport is critical.

1. Advanced Features

Bidirectional Detection

The SN2-TQZ Pig Passage Indicators are designed with the capability to detect pig movements in both upstream and downstream directions. This bidirectional detection feature is crucial for complete surveillance of the pipeline, ensuring no segment is left unmonitored. It allows operators to track the pig regardless of the direction it travels, enhancing the control over maintenance procedures and ensuring thorough cleaning or inspection processes.

Flexible Installation

Installation flexibility is a key design element of the SN2-TQZ. The device connects to the pipeline using a 2-inch flange. Which comes in two variants: REUV for mounting the ball valve above the foundation and REDV for mounting it below. This adaptability in installation options allows the indicator to be fitted onto a variety of pipeline configurations and orientations. By accommodating different structural requirements, the SN2-TQZ ensures optimal positioning for effective function and easy access for maintenance and monitoring tasks.

Immediate Feedback

The SN2-TQZ provides real-time alerts immediately when a pig is detected passing the sensor. This feature of immediate feedback is invaluable for operational efficiency, enabling swift response from the monitoring team. Real-time data allows for quick decision-making that can prevent potential issues or optimize the pigging process. The ability to act promptly on this information helps maintain the integrity and efficiency of the pipeline system, reducing downtime and enhancing productivity.

2. Features of SN2-TQZ Pig Passage Indicators

The SN2-TQZ is an intrusive bidirectional triggering pig detector that comes equipped with various display options to suit different monitoring needs:

• Display Type B. Features an indication flag that switches from horizontal to vertical when a pig passes.
• Display Type C. Similar to Type B, but also includes either an SPDT (Single Pole Double Throw) or DPDT (Double Pole Double Throw) switch that activates and remains in action.
• Display Type D. Incorporates a digital time display that begins counting and records the exact time of activation. It also includes SPDT or DPDT switch functionality, which remains active until a factory-set time before returning the display to standby.
• Display Type CD. Combines features of Types C and D, with a flag indication and a switch that activates upon a specific trigger deflection and resets after the trigger resets. The digital time display functions similarly to Type D.

So the SN2-TQZ is connected via a 2″ flange, available in configurations that denote the orientation of the ball valve related to the foundation—REUV for upper valve handling and REDV for lower valve handling under pressure.

3. Installation Process

Installation of the SN2-TQZ Pig Passage Indicator involves several critical steps to ensure proper function and reliability:

1. Flange Compatibility. The pipeline must be fitted with a flange that conforms to ANSI B 16.5 standards or customized specifications. With a specific distance from the flange top face to the internal wall of the pipe.
2. Sealing and Placement. A compatible sealing gasket should be placed between the two flanges to ensure the indicator’s trigger action is accurately aligned with the pipeline direction. The device is then inserted into the pipeline, and the flange seat is secured using screws.
3. Display Adjustment. The direction of the display (Types B, C, CD, and D) can be adjusted by loosening and tightening specific components to align the display correctly with operational viewing angles.

4. Maintenance Requirements

Seal Inspection and Replacement

Regular maintenance of the SN2-TQZ includes thorough inspections of both external and internal seals. External seals are visible and can be easily assessed for wear or damage. These can be replaced on-site by maintenance personnel using standard replacement parts. Internal seals, however, are more complex and integral to the device’s operation. If internal seals show signs of deterioration, it is recommended to return the component to the manufacturer for professional replacement. So this ensures that the seals are properly fitted and that the device maintains its integrity and functionality.

Safety Precautions

Safety is paramount when performing maintenance on the SN2-TQZ, particularly because it operates under varying pressure conditions within pipelines. Before any maintenance activities, it is crucial to completely depressurize the pipeline to prevent any accidental release of pressure during the process. This step protects maintenance personnel and prevents potential damage to the pipeline and surrounding equipment. All personnel should be trained in safety procedures and use appropriate protective gear when handling the pig detector.

Special Tools Required

Removing the SN2-TQZ, especially when it is under pressure, necessitates the use of specialized tools designed to handle the stresses and complexities of high-pressure environments. These tools typically include long bolts, standard nuts, and common spanners that are capable of safely disassembling the detector without causing damage to the equipment or risking the safety of the maintenance team. The use of these specific tools ensures that the device can be removed or installed efficiently and safely, maintaining the overall integrity of the pipeline system.