Emerson A6410 Dual-channel Valve and Case Expansion Monitor

Overview

The Valve and Case Expansion Monitor is designed for high reliability for

 

the plant’s most critical rotating machinery. This 1-slot monitor is used

 

together with other AMS 6500 monitors to build a complete API 670

 

machinery protection monitor. Applications include steam, gas,

 

compressors and hydro turbo machinery.

 

 

The main functionality of the Valve and Case Expansion Monitor is to

 

accurately monitor valve position and case expansion and reliably protect

 

machinery by comparing parameters against alarm set points, driving

 

alarms and relays.

 

Case expansion monitoring usually consists of two inductive displacement sensor (or LVDT’s) mounted in the axial direction, parallel to the shaft, and on each side of the turbine case. Unlike the eddy current sensor which is a non-contact sensor, the inductive sensor is a contact sensor.

Case expansion monitoring is important at start-up, so both sides of the turbine case can be monitored for proper expansion rates. Because the turbine is allowed to slide on rails as it expands, if both sides are not free to expand, the turbine “crabs” (the case bends), leading to the rotor colliding with the case.

Channel 1 can measure static values, such as case expansion, and can also be used for dynamic quantities, such as displacement, angles, forces, torsions or other physical quantities measured by inductive transducers. Channel 2 is left for static measurements and relative displacements (relative to channel 1).

Technical Specifications