Driven by quality design standards and regulatory updates, the valve industry has achieved significant gains in efficiency and safety.
By Bob Donnelly – Vice President of Business Development – Flo-Tite Valves & Controls
A lot of process control manufacturing operations are at risk of hazardous accidents. Safety regulations are continually instituted and monitored by the Occupational Safety and Health Administration (OSHA) to ensure compliance.
Additionally, ISO 9000 certification is another set of standards that valve companies comply with to manufacture and test their products. Likewise, major end users have their own standards for the valves they use in their process control operations, which are called Approved Manufacturers Lists (AML).
The primary concerns in the valve industry include leakage due to wear or poor sealing as well as high pressure or overpressure that can cause catastrophic accidents and explosions. Material and component failures from corrosion or exceeding operational life cycles are additional issues to manage. This is why standards have been developed to select, install, and maintain valves for specific process control applications. They are critical of mitigating risks.
Leakage and Solutions Leakage occurs from the cycling of valves, which causes wear on the valve seals, utilizing improper seat materials for the application, and/or debris getting lodged in the valve seat. This typically leads to the release of hazardous fluids, toxic gases, or flammable materials that can cause environmental pollution, fires, or in some cases, poisoning.
The result of these issues leads to valve corrosion, fatigue, and wear. They may also pose safety risks to plant operators, create economic losses, and increase liability issues for manufacturers. Additional risks include the potential for explosions in oxygen lines due to residual grease; hydraulic shock (water hammer) that can rupture pipes, and contamination from residues. Another serious safety situation is in the Food and Beverage industry where contamination can occur due to poor maintenance and residues in the valves.
Solutions for these situations include installing hydraulic shock accumulators, using specially designed cavity filler ball valves, and implementing strict safety protocols for process control operations and maintenance where these type valves are in service.
A new generation of sensing devices has become a routine part of process- control operations. When used with sophisticated automated manufacturing control systems, these represent significant progress in mitigating most historical safety concerns. Valve specifications have also become integrated into fully automated process control systems.
The use of specific technologies like AI can ensure that the right valve configuration is being installed for any application, as well as monitored during service.
Valve Component Enhancements Leakage and heat are the major sources of safety concerns with ball valves, which are the primary type of valves used in most process control operations. As a result, two simple solutions have been developed — stem extensions and media containment devices.
- Stem Extensions: Stem extensions are devices mounted on a valve and the actuator is installed on top of the extension. Their purpose is to limit the amount of process heat that reaches the actuator, preventing damage to its seats and seals, thus reducing the risk of failure to the actuator. This is a particularly serious problem when actuators are direct mounted on the valve without using a mounting bracket.
- Media Containment Device: Leakage from ball valves occurs from excessive cycling of the valve, which causes wear on the stem seals on the top of the valves. Media containment devices are modified stem extensions with a set of Bellville washers that function as an added set of stem seals. They can contain any leakage until routine maintenance can be performed on the valve.
They can also be installed while the valve is in service. This avoids the need to shut down the line and replace the valve to solve a potential hazardous safety issue.
Conclusion Great progress has been made in mitigating the majority of historical safety issues. With continued advances in regulations and standards, valve design processes, and the use of emerging technologies, the flow control sector is much more efficient and safer.