Published Nov 10, 2014

A new approach for efficient valve instrumentation

Automated process valves actuated by pneumatic actuators always need pneumatic and/or electro-pneumatic instrumentation components to build up the specific functionalities required for each application. Typically, these instrumentation components are mounted all around the actuator. The number of instrumentation components available in the market is huge. Additionally, even the most common functionalities can be built in many different ways.

This results in a complex mix of components and systems in a plant, creating challenges to run the plant operations smoothly when it comes to spare parts stock, service functions, modification work or repair in case component malfunction takes place. With such inevitable challenges, is it possible to make valve instrumentation simpler and easier?

End user challenge
End users typically only specify the instrumentation components that are wired to the DCS or ESD system, such as the solenoid valve, positioner or limit switch. These additional components may be specified based on technical properties or an exact product brand and model. However, the required functionality may require more than just the components that a customer has specified. Depending on the process medium and climate condition, also other component materials and temperature ranges can be specified generically – but specifications go no further than that. Therefore, standardization has occurred on some level, but it still leaves the door open to deal with a wide range of different components.This results in end users having a vast number of different instrumentation components installed in a plant and even the most common functionalities are builtin many different ways.

Single engineered solutions
As the number of instrumentation components available in the market is huge, various brands, parallel product series and different types of components can be used to execute the same functions. Valve assembly vendors have their own established practices on how to build up certain valve functionalities. They also generally provide their own preferred range of components. Additionally, identical valve functionalities can be built up from the selection of many different types of components. The most common automated process valve basic functionalities are on-off, critical on-off (ESD), control and control+- fail safe functions. The responsibility of sizing and selecting the components to build up these functionalities is part of the valve assembly vendor’s scope. Even by strictly following the customer’s specifications, each and every instrumentation selection is a single engineered solution. The advantage of a single engineered solution is that it is tailor-made for the specific valve. The downside is the large number of variations delivered that customers need to struggle with. Therefore, it is fair to say that valve assembly related instrumentation has so far been just a selection of individual components, and has not been seriously standardized or developed as one product.

End user objectives
End user objectives regarding valve assembly related instrumentation include the following:

  • Reliability: The number one objective is reliability. Plant production downtime for any unplanned reason results in production loss, even if it is caused by a single instrumentation component. Proven and tested components and systems are key to success.
  • Lowest total cost of ownership: Lowering capital and operational expenses is essential. This can be achieved with competitive prices and a long component life cycle.
  • Spare part stock size: The number of different component types used in a plant correlates directly to the size of the spare part stock.
  • Ease of installation and service: Testing and installation time during commissioning should be as short as possible. Servicing needs to be easy with fast tracking and changes of failed components.
  • Minimized space and weight: Smaller valve assemblies enable a more compact pipeline layout. A light and compact design is less sensitive to vibration problems and does not require additional support.
  • Service personnel expertise: A minimum number of different component types and instrumentation systems facilitate the work of service personnel.

Figure 1: Metso instrumentation panel ideology example: The solenoid valve is the non-standardized part of the panel; the rest of the components are standardized.

New approach to overcome challenges
To overcome these challenges, Metso has developed a completely new way to build up instrumentation functionalities. This new product called Metso instrumentation panel introduces a range of the most common process valve control functionalities. Typically, these functionalities are related to valve operation times and failure modes. Instrumentation panel is designed to meet the most stringent customer needs and withstand the most challenging plant environments.

Metso instrumentation panel for easy instrumentation selection
Defining the right function, sizing, as well as selecting individual instrumentation components requires significant engineering efforts. Metso instrumentation panel has been designed to help this task by allowing an easy way to select the right functionality and components to match the stroking time and other requirements. Metso’s instrumentation panels are predefi ned assemblies of pneumatic components. The instrumentation panels are designed to execute the most common process valve functionalities in the most efficient way. The instrumentation function panel is a highly modular and standardized product. Its basic ideology is that panel components are split into two categories: non-standardized and standardized components. Non-standardized components are the ones defined in a customer’s specification. Standardized components are the ones typically not in the customer’s specification, but they are needed to achieve the correct functionality and stroke speed.

Figure 2: With Metso instrumentation panel (on the left), all components are centralized on one panel plate, enabling simple installation and easy access to all components from one side. In single engineered solutions (on the right), components are typically assembled all around the actuator.

Metso instrumentation panel leads to efficiency and reliability
The instrumentation panel design principles and features support end users to achieve their objectives of efficiency and reliability. All panel components are widely used and well-recognized brands in the market. The vast installed base and long-term use of selected components verify the field-proven reliability and high quality. Panel operation is tested. After top works assembly, the entire valve assembly functionality is tested again.
The number of component types and models is minimized, which makes it possible to reduce the size and capital of a plant’s spare part stock. The component layout on the panel is standardized, which gives a homogenous look and layout to all of them. Moreover, it is easier for plant personnel to understand the system. Component layout on the panel allows easy, one-point access on site. Panel mounting on the actuator is fast and easy. For servicing or troubleshooting, the entire panel can be replaced by a spare unit and the actual service or repair work can be done in the plant service workshop. An important benefit is the reduced time of returning the valve back into operation.
The instrumentation panel components are selected to meet the most stringent requirements. The wide temperature range makes it possible to assemble this product in any process plant. Component material options offer a technically and commercially competitive solution for all process environments. The instrumentation panel is available with a SS316 material option. Components are SIL approved as standard, and explosion-proof solenoid valves are available as well, making it a perfect product, for example, to fulfill demanding offshore plant specifications. Instrumentation panel functionalities are available with a wide flow capacity range, and thereby available for all valve sizes. Pre-determined stroke times make it easy to select the right capacity size.

Single source supplier
Metso’s Flow Control product portfolio contains a full range of high-performance valves and actuators, including engineering, manufacturing and testing. This single source supplier approach provides customers with high-quality and fully tested valve assemblies.

Summary
The Metso instrumentation panel instrumentation product provides end users with signifi cant benefits. It increases the reliability of the valve assembly and reduces the spare part inventory and number of instrumentation components at a plant. Installation and maintenance is fast and easy, which results in direct cost savings. Selecting the right product for the process application is easy and straightforward.

By Antti Jokinen, Metso Automation

Previously published in Valve World magazine, 10/2014 issue, as 'A new approach for efficient valve instrumentation'.

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