Field Q is a neatly integrated automation solution, consisting of a pneumatic actuator, solenoid, switch box and various function modules that can be added according to customer’s requirements. The design objective was to be able to offer end users a one stop, standardised but flexible automation solution that El-o-matic can fit to any valve in its automation centres.
The conundrum that brought about the concept
While products are becoming more complex, with extra features and possibilities, personnel counts are having to be reduced - and valve or actuator specialists are being replaced by staff with more general skills. Field Q addresses that challenge by being a more capable product while at the same time simpler.
Using proven technology, the Emerson engineers based the new Field Q on existing El-o-Matic and Hytork components; with over two million units installed the company could extract the best features of these products, such as end of stroke adjustment and anodised internals for corrosion resistance.
Enhancements were then made to these proven designs. For instance, in the existing rack and pinion actuator, the pinion's diameter is smaller at the top. When pressurised, the ensuing down-force creates wear at the top of the actuator. Redesigning the pinion with the same size seals on the top and bottom eliminated the undesired down-force, reducing wear and tear in high-cycle performances.
The built-in preferred solenoid functions are based on a design that incorporates a membrane/poppet valve arrangement that combines low sensitivity to supply air pollution and the use of low power pilot valves. The membrane/poppet valve system also facilitates a high air volume without the need for a booster with larger actuators. This unique Field Q design was developed in collaboration with ASCO Joucomatic, a sister Emerson Company, taking consideration of real process plants situations.
Worth noting is the way the actuator can be integrated with the solenoid function, and a wide range of modules, with either limit switches or positioners. Its diagnostic capabilities permit the total valve automation package to provide a solution well suited to bus-driven control environments. With conventional IO, the information is there but cannot be accessed.
Emergency shutdown functionality check can be implemented by a partial stroke test, but only if it is known exactly where the pinion is - at that position. So Emersen daone totally enclosed plug-in function module per actuator, and the smart version incorporates a pushbutton auto initialisation facility. The end result is a single-sourced automation solution with easy installation and environment-proof protection.
Compactness is critical in brown field situations since many end users retrofit to automate existing manual valves. The flexibility of the Field Q is reflected in its modularity. The Series is made up of seven models ranging from 40 to 1600 Nm, double acting and spring return, complemented by a variety of on/off function modules such as ASi, profibus DP and PA and Foundation Fieldbus in the first release. The second release will have Hart, profibus DP, Foundation Fieldbus and straightforward 4-20 mA position control functions.
The Field Q can be used on quarter-turn ball, plug and butterfly valves and dampers. It is a full-featured actuator with visual indicator, double stroke adjustment and balanced pinion design. External air is prevented from entering the solenoid - a useful feature in potentially corrosive environment. Field Q is available with diagnostics options, such as break time, travel time, cycle counter and electronics failure.
Extra features such as torque measurement will be available in later releases. The Field Q can store values for future comparison and set off alarms should deviation limits be exceeded. The basic measurements will be performed in the Field Q, but their interpretations and solution will be provided at higher level using software such as AMS, or AMS-inside a configuration and maintenance tool integrated into the Emerson Fieldbus system Delta-V. Importantly, this is an open system, so other field devices may be linked to it as well.
For more information contact El-o-matic, 011 974 3336.
© Technews Publishing (Pty) Ltd | All Rights Reserved
printer friendly version