Key Benefits and Advantages
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Superior Debris Protection: The LR128 is built for “dirty” liquid environments. The internal flow path is specifically engineered to deflect particulates away from the critical seating surfaces. Furthermore, an integrated stainless steel inlet strainer captures larger debris before it can enter the main valve, preventing the erosion and seat damage that often plague standard relief valves.
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Metal Plug Design: The use of a robust metal plug eliminates the common failure points of flexible element or boot-style regulators, such as tearing, swelling, or degradation over time. This design ensures a consistent, tight shutoff and a much higher degree of mechanical durability.
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Smooth and Stable Operation: The pilot-operated architecture ensures that the valve opens and closes gradually and precisely. This smooth operation is critical in liquid systems to prevent the water hammer and pressure surges that can occur with fast-acting, direct-operated relief valves.
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In-Service Travel Indicator: A standard visual travel indicator allows maintenance personnel to verify the position of the main valve plug during operation. This feature simplifies troubleshooting and performance monitoring without the need to take the system offline.
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Thorough Laboratory Testing: Like all Fisher products, the LR128 has undergone extensive flow and endurance testing. This ensures that the published relief capacities are accurate and that the valve will perform reliably during emergency overpressure events.
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Easily Maintained Pilot: The control pilot is designed for simplicity and accessibility. It can be serviced or adjusted in the field with minimal tools, ensuring that the backpressure or relief setpoint remains accurate over the life of the installation.
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Tight Shutoff: The combination of precision-machined metal internals and high-quality seating materials allows the LR128 to achieve a bubble-tight seal, preventing fluid loss when the system is operating below the relief setpoint.
Technical Properties
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Operation: Pilot-operated relief or backpressure.
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Service: Liquids (Water, Liquid Fuels, Process Fluids).
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Body Sizes: Available in standard industrial sizes, typically ranging from NPS 1 through NPS 8.
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Pressure Ratings: Designed to meet high-pressure industrial piping standards.
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End Connections: Flanged connections (ANSI/ASME) for easy integration into high-volume liquid headers.
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Materials: Durable cast iron or steel bodies with corrosion-resistant internal trim.
Field of Application
The Type LR128 is the ideal choice for liquid systems where precision backpressure control and debris resistance are essential.
Primary Industries and Uses:
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Pump Bypass Systems: Maintaining constant pump discharge pressure by recirculating excess liquid back to a storage tank.
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Water Distribution: Acting as a high-capacity relief valve to protect municipal and industrial pipelines from overpressure.
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Fuel Loading Racks: Managing backpressure during the high-volume transfer of liquid fuels and oils.
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Fire Protection Headers: Ensuring stable pressure in fire water systems by relieving excess pressure during pump starts.
