Pneumatic valve LST

hydraulicelectricfor water

Overview
LST (Longer Serviceable Trim) is an upgrade trim designed to reduce cavitation and erosion at low-flow conditions, extending component life and improving control performance in demanding liquid-service control valves.

Key benefits

• Extends trim service life by up to four times in low-flow conditions
• Reduces cavitation damage to protect seating surfaces
• Improves control stability and turndown in critical applications

Longer Serviceable Trim (LST) — summary
LST from IMI CCI is a retrofit solution for 840 Series and 860 Series control valves operating at or below their intended range. Conventional trims can concentrate high-velocity flow and cavitation at the seating surface when valves operate at low openings, causing accelerated wear, leakage and reduced reliability. LST repositions pressure-drop locations and integrates controlled flow features to maintain stable control at low openings while protecting critical components, improving performance and extending service life in liquid applications.

Where issues occur
At low flow the engineered passages in a control valve close and control shifts to the clearance between plug and cage. This concentrates energy and promotes cavitation directly at the seating surface, accelerating erosion and degrading control performance.

What LST changes
LST redistributes pressure drop away from the seating surface and introduces features that manage flow and velocity within the trim. The result is reduced cavitation intensity at critical points, stabilized control at low openings and limited component damage, extending maintenance intervals and increasing reliability across a wider operating range.

Key features

• Plug nose shifts vena contracta downstream
• Labyrinth grooves reduce clearance Cv
• Gap control stabilises low flow
• Anti-cavitation cage design
• Protects seating surface
• Maintains control at low openings
• Smooth transition to full flow
• Retrofit-compatible design
• Supports high rangeability
• Extends maintenance intervals

Technical specifications

• Design Codes: ASME B16.34
• Certification: PED; ATEX; CRN; TSG
• Material: Carbon steel; Alloy steel; Stainless steel
• Max. ASME Rating: 1500
• Temperature limits (°C): -29 to 260
• Actuator type: Pneumatic; Electric; Hydraulic
• Fluid types: Water; Liquid
• Trim category: Single stage; Multi-stage
• Service category: General