For years, a major Canadian natural gas distribution company struggled with frequent servicing of the more than 20,000 plug valves on its network. Every 12-18 months, operators would have to lubricate and turn the valves, often in extreme cold conditions.
Whether in buried or above ground service, the grease or lubricant injected into these types of plug valves would eventually end up in the system, plugging filters and damaging regulators. As it is difficult to accurately measure the amount of grease required, operators would have a tendency to over-lubricate the valves; leading to more lubricant in the system.
Eventually, the company began to experience serious problems from over-lubrication as valves seized and could not be operated. In the event of a fire, tight shutoff is critical. The company was required to pay a steep fine (>$1M) in order to comply with safety requirements and ensure that all of the plug valves on its network were fully operational and safe.Extreme conditions tempted operators to remain in their trucks
As it is difficult to accurately measure the amount of grease required, operators would have a tendency to over-lubricate the valves
The natural gas distributor’s research facility had previously purchased three buried service Boehmer ball valves from Armour Valve. These valves are maintenance free under normal conditions and were evaluated for use in a project involving the sectioning of a central network into smaller networks to contain disturbances to a smaller area.
The Boehmer ball valves proved reliable in testing and were proposed as potential replacements for the high-maintenance plug valves.
The valves were considered as an attractive solution due for the following reasons:
- Maintenance-free under normal conditions
- Fully welded and forged bodies provide a benefit over a bolted body valve
- Spring-supported seat rings ensure tight sealing at low pressures
- Trunnion mounted balls have self-lubricating bearings
- Anti-blow out stems ensure stem sealing through various independent sealing systems
- Anti-static design is fire safe and can be provided with emergency sealant if requested
The company gradually replaced the plug valves on their network with Boehmer ball valves.
While this was a major undertaking spanning several years, the benefits of switching to a solution requiring no routine maintenance have been experienced by stakeholders across the company’s distribution network.
End users benefited from a safer and more reliable service; maintenance personnel were required to lubricate fewer and fewer valves annually, often in temperatures well below freezing; and the company was able to mitigate a costly compliance and safety risk.