Most of us know when an application is severe. But what is it that makes it severe for a valve? Defining Severe Service Valves (SSVs) objectively is an important tool in attaining improved process control, safety, profitability, and environmental stewardship.
SSVs can be defined as industrial valves specifically designed to perform in the most extreme conditions without failing. These conditions often include a mix of differential pressure scenarios, corrosive materials, solids in solution or suspension, frequent or infrequent cycling, and extreme temperatures.
It is important to recognize that there are a variety of different types of Severe Service Valves. Broadly speaking, SSVs are made up of the following three subcategories:
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- Severe Service Control Valves (SSCVs)
- Severe Service Isolation Valves (SSIVs)
- Severe Service Check Valves (SSCKVs)
Severe Service Control Valves — SSCVs
A Severe Service Control Valve can be defined as a control valve that performs within a process where one or more of the identified thresholds is surpassed. Typical thresholds include, but are not limited to:- cavitation σ > σi
- erosive flow > 8m/s inlet
- high noise > 85 dB
Severe Service Isolation Valves — SSIVs
A Severe Service Isolation Valve can be defined as an isolation valve that performs within a process where one or more of the identified thresholds is surpassed. Typical thresholds include but are not limited to:- 1mm/year
- high alloy construction B16.34 > Group 2.4
- hslurry 10% solids > 20 barG