Keeping an eye on the
other guy’s customers
Emerson based its design decisions for a new valve and actuator on a customer survey

Users have shown the way forward: less is more. One of the key design
goals for the developers of Emerson’s new valve and actuator was to reduce complexity: fewer different types of components and simpler component design. The following article reveals tips from users that are reflected in the design of the device.

You claim that you know what your customers want? That’s fine, but how about potential buyers of your products, the people who for whatever reason have given you the “cold shoulder”? This is precisely the approach that the Fisher Division at Emerson Process Management took during the planned enhancement of its product range. The company was already a producer of valves and controls for refineries and power plants. Now the company wanted to develop a completely new product line for the chemical and petrochemical industries. An anonymous survey was conducted with companies which were not Fisher customers and which are involved in all types of applications in the UK, Italy, Holland, France and Germany. The key results were as follows:
“installed costs” are important;
dissatisfaction with the current supplier is mainly related to delivery performance;
the majority would prefer to place orders by phone or fax; visits by salesmen should be spaced at long intervals;
currently, there is no interest in using the Internet for business transactions.
Users’ technical requirements for a potential new valve and actuator can be summarized in three categories: ease of operation, ease of maintenance and service life.

Ease of operation
simple selection, multi-language capability
simple settings and adjustments, local operation
fast, simple installation
models that comply to European standards
reconfiguration during operation
Ease of maintenance
packing integrity
very fast replacement and quick resumption of operations
appropriate diagnostic functionality for the valve and the actuator
minimal stock of spare parts
Long service life
resistance to a corrosive atmosphere
non-leak fit over a long period of time
The new valve and actuator
The result of the analysis and subsequent development work was the Fisher GX valve and the DVC 2000 actuator. The GX is available in sizes between DN 25 and DN 100. The flow characteristics in the valve housing were optimized for stability and high flow rate. The user no longer needs to calculate the size of the drive because this parameter is defined by the selection of the valve housing. The new valve delivers reliable closing performance up to 51 bar. The direction of spring action in this multi-spring membrane drive can be changed on site without the need for additional parts. Packing made of spring-loaded PTFE V-rings belongs to the standard configuration and stays leakproof for a long time. Shutoff classes IV, V and VI are available. Graphite packing and an extended bonnet can be supplied for temperatures above 232 °C.
In response to the requests for compliance with European standards which have often been expressed, accessories are attached to the GX in accordance with Namur requirements. The valve complies with both EN and ANSI standards. A large selection of materials including special materials is available for use in a wide range of applications. Also, many parts are the same on all sizes, and this simplifies maintenance and stock requirements.
The companion DVC 2000 actuator was designed to conform to European standards especially for the European market. It features a compact, intrinsically safe design. A multi-language LCD display and four pushbuttons are used to operate the device. The actuator delivers the same performance as all of the products in Emerson’s Fieldvue family of products. The controller provides real time diagnostic and monitoring capability and is compatible with digital PlantWeb architecture. It helps improve system operation and maintenance by giving the user additional information about the control valve and the status of the process. The linkage-less position feedback system, a non-contact design which uses no mechanical feedback parts, is a particularly innovative feature. It minimizes the effort required to replace the actuator, because there is no mechanical connection between the stroke sensor and the valve spindle.
A local, multi-language user interface provides access to a quick setup routine, which enables the user to adjust the stroke and adapt the actuator parameters to suit the drive that it is attached to. The result is stable, high-precision performance. Options including integrated limit switches and integrated position feedback make it easier to select an actuator because less engineering and specification effort is required. Features such as modular design and self-diagnostic functions make maintenance easy and fast on the DVC 2000 series. The Hart protocol is used to communicate critical information about the status of the valve and control to persons working on the system. MS ValveLink software can be used for the communications link, or data can be transferred directly to the PLS. Real time information facilitates early detection of problems and initiation of suitable corrective action before problems lead to unscheduled down time. As is the case with the DX drive, the DVC 2000 was designed to conform with European standards. Since it conforms with IEC 60534-6-1 and IEC 60534-6-2 (Namur) standards, the controller can be mounted on Fisher valves as well as on drives from other manufacturers.
Controller functionality is based on two essential features: a dual stage preamplifier design, which amplifies minute changes in the pneumatic signal, and a digital tuning algorithm which is used to tune the controller to the specific actuator. The DVC 2000 is approved in accordance with Cenelec, FM, JIS, CSA and SAA requirements for use in intrinsically safe, zero explosion risk environments, and it complies with the Atex and EMC directives, IEC 60529 IP66 and Nema 4X criteria.