In the process industry, powerful sensors are needed to monitor the correct position of valves. Some outdoor applications, such as seawater desalination plants, oil rigs or phosphate mines, place particular demands on the sensor technology used. With a tight and corrosion-free housing, the F31K2 dual inductive sensor from Pepperl+Fuchs offers a solution for valve position feedback under such extreme conditions.
The company’s optimised sensor series also includes a non-intrinsically safe variant with IECEx approval for worldwide use in Zone 2/22 hazardous areas. In addition, a low-power variant enables simple modernisation of existing systems with mechanical limit switches.
Optimised for outdoor use
Exposed to heat or cold, salt water or UV radiation, the F31K2 has the robustness and durability to withstand the most adverse outdoor conditions. Two separate inductive sensor elements enable noncontact and wear-free detection of the valve position. The high-density housing (up to IP69) makes the F31K2 insensitive to water and dust. The materials used – V4A stainless steel, high-performance plastics and coated aluminium – additionally protect the sensor against corrosion. With an extended operating temperature range of -40 to +70/+100°C, the F31K2 can be used in extreme weather conditions. In addition, a protective cover is available to protect the actuator from mechanical damage and dirt.
Variants offer greater flexibility
The dual sensors of the F31K2 series are available with different approvals and electronic outputs. A special highlight is the 2-wire dc low-power variant. Due to patented Pepperl+Fuchs technology, this dual inductive sensor has a virtually volt-free contact. As a result, the residual current is so low that the sensor can be used in combination with all programmable logic controllers and process control systems. This means a modern inductive solution is also available for systems that previously relied on mechanical contacts.
In areas where explosive atmospheres rarely occur, the required explosion protection can be implemented particularly easily with the 2- or 3-wire dc variants. The sensors are designed for use in Zone 2/22 where Ex ec (increased safety) and Ex tc (protection by enclosure) types of protection with ATEX and IECEx certifications are required. Consequently, neither isolated switch amplifiers nor intrinsically safe wiring is needed when these devices are used. For hazardous areas up to Zone 0/20, the intrinsically safe NAMUR version of the F31K2 provides the appropriate ATEX and IECEx approvals. This variant of the dual inductive sensor can also be used in safety applications up to SIL 2.
Simple mounting, convenient operation
The compact F31K2 dual sensor can be mounted directly on valve actuators without additional accessories, making it easy to install. A large terminal compartment with plug-in terminals provides additional convenience. Pepperl+Fuchs offers a selection of actuators in different sizes so that the F31K2 can be adapted to different drives. The portfolio also includes an actuator with a highly visible, coloured valve position indicator: this makes it possible to see at a glance whether the valve is open or closed, even from a distance. The F31K2 thus offers maximum convenience for valve position feedback in process plants.
For more information visit: www.pepperl-fuchs.com/southafrica/en
