The HON Cocon 13 is a self-contained underground gas regulating station designed for reducing gas pressure in distribution and industrial applications. It can be fully buried or installed above ground, occupying a significantly smaller area than conventional regulating stations. The system ensures a reliable gas supply at a constant pressure, independent of gas consumption.
Function Description
The HON Cocon 13 is a twin-stream gas reducing system, configurable in several ways, such as:
- Both lines operating as Active regulators with Safety Shut-off Valves (SSV).
- One line operating as an Active/Monitor regulator and the other as an Active/SSV.
Gas flows from the inlet to the outlet, passing through an inlet valve, filter, monitor, worker, and outlet valve. The station's working elements are contained within a removable cartridge, housed in a steel body installed underground. A vent stack above ground contains vent pipes for atmospheric reference and the relief valve.
Two operation modes are possible: active and monitor control. Both modes operate identically and can be reversed during testing and operation. In normal operation, the upstream control valve monitors the outlet pressure in a wide-open position, while the downstream valve reduces inlet to outlet pressure in a throttling position. Control is based on cascaded loops (master and slave) for reliability and accuracy. The outlet pressure is determined by the dome-load (motorization) as set and corrected by the pilot.
- Active Control (Low Pressure): If the dome load (active motorization) on the active valve exceeds the outlet pressure, the diaphragm moves upward, increasing stem travel and allowing the active valve to compensate for low pressure.
- Active Control (High Pressure): If the outlet pressure exceeds the dome load, the diaphragm moves downward, decreasing stem travel and allowing the active valve to compensate for high pressure.
- Monitor Control (Low Pressure): If the dome load (monitor motorization) on the active valve exceeds the outlet pressure, the piston moves downward, increasing stem travel and allowing the active valve to compensate for low pressure.
- Monitor Control (High Pressure): If the outlet pressure exceeds the dome load, the piston moves upward, decreasing stem travel and allowing the active valve to compensate for high pressure.
- Pilot Control: The set point is adjusted via a screw on top of the pilot. As dome load and spring force vary with stem travel, the outlet pressure may deviate from the set point. Upon deviation, the pilot opens or closes to correct the dome load and, indirectly, the outlet pressure.
The system includes a Safety Shut-off Device (SSD) valve and controller. If the regulator malfunctions and the outlet pressure rises above a set value, the SSD valve automatically cuts off the gas supply. The valve can be reset manually after the cause of the pressure rise is rectified.
Important Technical Specifications
- Medium: All types of gases except Sulphur-containing gases (H2S). Stations for H2S are available on request.
- Inlet Pressure (p1): Maximum 20 bar (ANSI150).
- Outlet Pressure (p2): Minimum 20 mbar (2 kPa).
- Minimal Δp (p1-p2): 0.5 bar.
- Temperature Range (ambient): -20 °C to +60 °C.
- Flow Coefficient: Cg value (EN 334) 435.
- Total Weight: Approximately 300 kg.
- Cartridge Weight: Approximately 40 kg.
- Packed Volume: Approximately 1.5 m³.
- Dimensions: Maximum 1435 mm (incl. header) length, 860 mm width, 980 mm height.
- Connections: 2" inlet, 4" outlet, according to ANSI 150.
- Impulse Line Connection: Metric fittings according to DIN 2353.
- Pressure Gauges: 2 or 3, for measuring inlet, (intermediate) and outlet pressure, 1½" BSP thread.
- Regulator Type: Two-path pilot operated spring-loaded closed gas pressure regulator.
- Shut-off Valve Type: Direct acting safety shut-off device (SSD) with integral pressure equalizing (Push button type).
- Filter: Cartridge filter with support cage, felt material, 3 micron (0.003 mm) fineness.
- Safety Devices: SSD valve with SSD controller.
- Materials: Steel, aluminum, bronze, and synthetics. Other materials available on request.
Usage Features
- Pre-assembled Skid Package: Reduces on-site installation time.
- Underground Installation: Minimizes required surface area.
- Removable Cartridge: Working elements are contained in a cartridge, allowing for quick replacement (within 20 minutes) with a pre-adjusted spare cartridge.
- Emergency Stop: A control button on the slam shut valve controller allows immediate shutdown of the cartridge.
- Pressure Gauges: Two gauges read inlet and outlet pressures, visible when the pit lid cover is opened.
- Purge Valves: For depressurization of the unit.
- Optional Relief Valve: Vents excess pressure to atmosphere in redundant stations due to leakage.
- Optional Valve Position Indicator (SSV): A proximity switch can be mounted on the Plexiglas cover of the slam shut valve for remote indication.
- Automatic Operation: The station operates automatically once correctly installed and set. In case of a major malfunction, the cartridge automatically shuts off the gas supply.
Maintenance Features
- Regular Maintenance: Advised for long and smooth operation, despite few moving parts.
- Cartridge Replacement: Quick and easy replacement of the cartridge, with maintenance performed in a service shop.
- Lubrication: Moving parts are self-lubricating or do not require additional lubrication during normal operations.
- Replaceable Parts: Upper seal rings, lower seal rings, and dust filters can be replaced on-site by the operator. Other parts require a qualified maintenance engineer in a service workshop.
- Dust Filter Replacement: Replace when excessively polluted. Breathing protection is required, and the cartridge should be removed carefully from the station.
- Seal Ring Replacement: Replace in case of leakage. Ensure seal rings are sufficiently greased with a low viscosity, gas-resistant gel (e.g., Parker Super-O-Lube).
- Storage: Spare units should be stored in clean, dry, vibration-free storerooms. Seal rings should be greased or covered with talcum powder to prevent desiccation. Cartridges should have a preservation layer to prevent oxidation and should not be exposed to extreme temperatures. Pilot spindles and shut-off relays should be turned to the left to minimize spring pressure.
- Adjustment Form: A dedicated form is provided to record adjustment data, name, date, station number, and unit number, facilitating tracking and management of multiple stations.
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