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SA Instrumentation & Control Buyers' Guide

Technews Industry Guide - IIoT 2018

Technews Industry Guide - Maintenance, Reliability & Asset Optimisation


Advanced slurry valves promote ­efficiency and productivity
August 2018, Valves, Actuators & Pump Control

There is sound reasoning for using advanced slurry valves in a number of industries where targeted efficiency and productivity require process parameters that may seem totally intolerable for materials and construction – namely non-stop exposure to abrasive and erosive solids that often move at very high velocities.

Fully complying with engineering codes, safety standards and emission requirements is a good starting point. But creating genuine added value only comes from the extra performance that can be offered on top of just the minimum requirements. With intelligent instrumentation and digitalisation, processes can be maintained and serviced based on the actual condition of the equipment, instead of the assumed or average equipment condition. Then, when reliability and performance is consistent, maintenance operations can be put on a planned schedule. In the best case, maintenance shutdowns can be shorter, safer and less frequent, since technological improvements can extend the effective lifetime of key equipment such as valves.

Withstanding harsh conditions

Slurry valves are part of critical process control in several industries, in applications for which the targeted efficiency and productivity require process parameters that may seem totally intolerable – for any material or construction. In the most severe applications, slurry processing valves must withstand nonstop exposure to abrasive or erosive solids that move at very high velocities, often at high temperature.

Despite the careful sizing of control valves, flashing and cavitation are sometimes unavoidable, which further increases the loading of internal surfaces in valves. Also, the medium may contain chemicals capable of dissolving metals very quickly. Taking mining and metallurgy processes as an example, valves often operate in an extremely demanding environment. Then it becomes necessary to find both the optimal valve design and the best construction materials for each component.

In isolation service, knife gate valves have been used for slurries when the characteristics of the medium do not prevent reliable closing or opening. But this type of valve design is not the most optimal for control service. Pinch valves have been used in slurry applications, but are not an option at higher temperatures – above the safe temperature range of rubber materials. Valve designs based on metallic construction materials and a rotating closing member generally offer the best combination of reliable operation and component durability over the widest range of parameters.

Material innovations for severe service

For slurry media, innovations in wear-protection materials and the development of functional coatings have both contributed to supporting the use of metallic, metal-seated valves in severe control service.

During the current decade, the use of innovative wear-protection materials in the construction of Metso ball valves has resulted in encouraging results in severe slurry control service, even with operating pressures up to 30 bar and temperatures of 200-300°C. The Metso Wear Block materials include metal matrix composites, in which the erosion resistance approaches the performance of ceramic materials, while the mechanical and electrical characteristics are like metals. Depending on the process environment for each application, the final material selection is matched to specific requirements for corrosion and wear resistance – and to the targeted maintenance schedule and overall lifetime. For each case, a broad range of details matter when selecting the material that can live up to the expected performance.

Favourable results

The outcome of using these Metso wear-protection solutions has helped to multiply the effective lifetimes of valves. In the most successful cases, these improvements have reduced operational and valve replacement costs by more than 90%. This means a similar reduction in potential HSE risk situations due to replacement or repair work – or due to cases of unexpected valve failures, if maintenance is delayed.

These achievements also help with environmental sustainability, since equipment manufacture, service operations and logistics consume fewer materials and much less energy. In addition to efficiency, an uninterrupted production process generally has a very positive effect on product quality, a prerequisite for better productivity in any industry.

For more information contact Metso South Africa, +27 31 502 9350,,

Supplied By: Metso South Africa
Tel: +27 31 502 9350
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Further reading:

  • Control of abrasive slurries
    October 2018, Bearing Man Group t/a BMG, Valves, Actuators & Pump Control
    BMG’s range of industrial slurry valves, which are designed to cope efficiently in harsh mining conditions, includes robust butterfly and knife gate valves, as well as diaphragm and pinch valves. “These ...
  • Schubert & Salzer stabilises paper production
    October 2018, Macsteel Fluid Control, Valves, Actuators & Pump Control
    The Austrian company, Grünewald Paper, recently modernised its process control to improve profitability. Thanks to a new control system and a grammage-weight control valve, the company’s throughput and ...
  • Quarter-turn actuator for dosing ­applications
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    Thanks to its versatility and flexibility, Festo’s quarter-turn actuator DFPD can be used in a variety of applications. Its modern, simple and compact design impresses whether it is used with ball valves, ...
  • Arca’s new approach to severe-duty microflow valves
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    Control valves are used in a wide range of capacity, from butterfly valves with a rated flow coefficient (KVs) of more than 50 000 m³/h, enough capacity to fill an Olympic swimming pool within three minutes, ...
  • Richter launches largest PFA lined ball valve
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    Richter, a leader in PFA lined pump and valve solutions, has introduced a new size control ball for its KNR and KNAR control valve series. Increasing production quantities require a larger diameter of ...
  • The benefit of head-guided plugs on slurry valves
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    “Good guiding of the plug head with three or more guide bars offers better benefits to valve performance than otherwise offered by the conventional method of fitting guides around the shaft,” commented ...
  • Blowdown applications using multi-stage trim
    July 2018, Valve & Automation, Valves, Actuators & Pump Control
    The Arca angle style control valves series 350 and 380 are proven under critical process conditions. If used in steam or other process gas applications at high pressure and temperature, in cavitation-free ...
  • Sliding gate valves in control at PVS
    May 2018, Macsteel Fluid Control, Valves, Actuators & Pump Control
    Belgium-based PVS Chemicals produces extremely pure chemicals for use in the semiconductor industry. One of the company’s outstanding innovations is the production of ultra-pure sulphuric acid. As the ...
  • Test unit for control valves
    May 2018, AT Technical Services & Supplies, Valves, Actuators & Pump Control
    Although plant designers tend to treat them as ‘necessary evils’, it is obvious that control valves play a key role in process quality and reliability. Extreme care must be taken to avoid costly premature ...
  • Optimised pump ­performance
    May 2018, SKF South Africa, Valves, Actuators & Pump Control
    Ignoring pumps is a risk because when these components break down, or run below optimum efficiency, the whole process suffers. Manufacturing and process companies are always under cost pressure, making ...
  • Condition monitoring can have a positive impact on OEE
    Technews Industry Guide: Maintenance, Reliability & Asset Optimisation 2018, Metso South Africa, Maintenance, Test & Measurement, Calibration
    Alerts and alarms provide some specific diagnostics that lead to a corrective action (i.e., for a car, pump the tyres with air), which leads to improved results and operation (i.e., fuel efficiency, reduced ...
  • Sealed bearings eliminate common failures in triple offset valves
    April 2018, Valve & Automation, Valves, Actuators & Pump Control
    Bearing failures are among the highest root causes of failure in triple offset valves (TOV) for tight shutoff applications. This issue is directly attributed to the need to have metal bearings with very ...

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