Critical Technical Advantages
Unsurpassed Emission Control: Enhanced ENVIRO-SEAL systems are engineered to help plants comply with the U.S. Clean Air Act and international standards. Depending on the configuration and process conditions, these systems can control emissions to below 100 ppmv (EPA maximum), 50 ppmv, or as low as 1 ppmv.
Live-Loaded Constant Pressure: The core of the system is a set of Belleville springs that provide “live-loading.” This mechanism maintains a constant force on the packing as it wears or as the stem cycles, effectively eliminating the need for frequent manual tightening and preventing leaks caused by thermal expansion or contraction.
Extended Service Life: By combining a very smooth stem surface finish with consistent loading, the ENVIRO-SEAL system minimizes friction and wear. This results in a significantly longer life for both the packing material and the valve stem, reducing total cost of ownership.
Versatile System Options: The “enhanced” family includes specialized versions to meet specific application needs:
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ENVIRO-SEAL: The standard for high-performance emission control.
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ENVIRO-SEAL IS (ISO-Seal): Optimized for international ISO standards.
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ENVIRO-SEAL HS (HIGH-SEAL): Designed for high-pressure or severe service requirements.
Universal Compatibility: These systems are available for both sliding-stem and rotary valves. Because they are modular, they can be specified on new valve orders or installed in existing Fisher valves using convenient, all-inclusive retrofit kits.
Integrated Guiding and Sealing: Beyond preventing leaks, the ENVIRO-SEAL system assists in stem guiding, ensuring that the loading force is transmitted evenly. This alignment further reduces side-loading wear on the packing and the valve trim.
Technical Performance Matrix
| Feature | Details |
| Emission Rating | < 100 ppmv (Standard) to 1 ppmv (Specialized) |
| Loading Mechanism | Live-loaded Belleville Spring Sets |
| Packing Materials | PTFE, Graphite ULF, or Duplex (PTFE/Graphite) |
| Valve Compatibility | Sliding-stem (Globe) and Rotary (Ball/Butterfly) |
| Installation | Factory-installed or Field Retrofit Kits |
| Maintenance | Self-adjusting (Reduces manual intervention) |
Primary Applications
Environmental Compliance (LDAR): Meeting Leak Detection and Repair (LDAR) mandates in chemical plants and refineries.
Hazardous Fluid Service: Handling toxic, flammable, or polluting fluids where zero-leakage is a safety requirement.
High-Cycle Service: Protecting valves in fast-cycling control loops where traditional packing would wear out prematurely.
Vacuum Service: Ensuring atmospheric air does not enter the process during vacuum operations.
Steam and Thermal Oil: Managing the thermal cycling of high-temperature media without frequent packing box leaks.
