ProNamics Control Inc.

Control Valve Testing Kit
Control valve performance is an important factor in achieving good process control and process performance.
Test Kit Components:
  • High resolution LVDT
    (Linear Variable Differential Transformer)
    • Valve position resolution is 0.05%
    • Standard LVDT stroke range is 2 inches
      Can measure 0 to 100% travel on:
      • 2.5" diameter rotary valve shaft
      • 6 to 8 inch globe valve
    • Optional 100 mm & 200 mm (4 & 8") sensor/transmitter are available
  • 3 wire 4 to 20 mA Transmitter
  • Data acquisition cable
  • 24 Vdc power supply
  • Mounting hardware for rotary and sliding stem valves
Poor Control Valve Performance:
  • limits control performance
  • induces process variability
  • Increases energy and chemical costs
  • limits production
  • Increases maintenance costs
  • Reduces maintenance reliability
Control Valve Performance Testing:
  • Identifies valves requiring repair based on performance
  • Quantifies backlash and stiction issues(deadband issues)
  • Document valve performance prior to installation
  • Ensures valve performance meets mill specifications
  • Ensures valves are maintained to offer optimum control performance
 		Control Valve Test Kit
Applications:
  • Test new/rebuilt control valves on the bench prior to installation
  • Test control valves in line during shutdowns
  • Test control valves on the run while conducting output bump tests
  • Test control valves with noisy process measurements
  • Test control valves on process measurements which are difficult to evaluate valve performance (levels)
Price & Delivery:
  • The ProNamics valve testing kit is very affordably priced
    • $4600 CDN
    • $4000 USF
  • 8 weeks delivery

Background

Poor control valve performance is a very important contributor to process variability. Excessive backlash and stiction, poor positioner tuning and over sizing are key factors that compromise control loop capability and in many cases are directly responsible for generating process variability. A reasonably good target range for combined backlash and stiction is between 0.5 and 1%. Unfortunately, most distributed control systems are not capable of displaying process with enough resolution to measure within this range. High speed, precision data acquisition equipment is required to measure and display small changes in the process signals and to evaluate the valve response time adequately. The simplest method for evaluating valve performance involves connecting high speed data acquisition equipment to the controller output and process variable (input) signals, placing the controller into manual mode and conducting a series of output steps. The output steps are typically in the range of 0.5 to 4% and valve movement is indicated by a change in the process variable. This is an efficient approach, but there are situations where it is not adequate. These situations include the following.
  • There is no direct process signal to measure.
  • The process signal is very noisy and/or the process gain on the loop is very low, and the process response is within the noise band
  • The process sensor is heavily filtered, masking the actual valve response.
  • The valve needs to be tested prior to installation to verify performance specifications.
    • In these cases further work is required. It is necessary to conduct the open loop bump tests while measuring both the controller output and the valve position. Since the majority of control valves are not fitted with a position sensor, a portable unit is required that can be easily fitted to the valve assembly and can measure the valve position with the required speed and resolution.


    BACKLASH TEST


    STEP TEST

    About Pronamics

    ProNamics Control Inc is a Vancouver, B.C based pulp and paper process control consulting company. The company conducts process and control optimization surveys, provides a range of training courses related to process control optimization, and markets process variability software and training tools.

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