Effective Valve Field Service

Understanding the cost and time savings of on-site service gives plant operators the ability to handle the hazards and logistics of maintenance on their own terms, while employing a methodical and organized workflow. Using predictive maintenance technologies, such as mobile diagnostics, operators can anticipate critical component failure based on real-time variables before the failure leads to lost production or an emergency shutdown.

Critical to implementing this type of maintenance program is a proven, fully qualified vendor with the ability and skills to perform any and all type of maintenance and repair service under on-site operating conditions, as well as off-site shop conditions. The vendor's technicians must be fully trained and certified to the same standards as plant employees and capable of bringing all of the plant's operating components to manufacturer and operating system specifications.

Perform Diagnostics
While all plant components, ranging from large rotating equipment to control valves, have life cycles based on the process application, the operating conditions, and the frequency of the operating cycle, valves and actuators are integral to the health and safety of overall operation and equipment. Because of this, valve diagnostics lead the way in applying predictability to plant technology. The results of a valve diagnostic analysis provide operators with the information they need to make decisions on the level of repair based on the priority of a particular process control point.

Field maintenance and the repair of valves, actuators, and other plant equipment requires mobile field units with at least two technicians. These units are fully equipped with repair and diagnostic equipment for control valves, engineered valves, motor operated valves, and pneumatic cylinders equipped with positioners, as well as spare parts, replacement valves and actuators, and all the equipment required for servicing, machining, and welding both normal and severe service materials.

The field service technicians staffing these mobile units must be trained and certified by a local contractor safety council in reciprocal basic safety, in addition to being qualified by the Department of Transportation. Quality technicians should also be trained to perform services within the published guidelines and specifications of original equipment manufacturers (OEMs), and even factory trained by several OEM valve manufacturers. The technicians should also be experienced in all aspects of equipment service repair from simple bolt and nut torquing, to extremely complex customer requirements and solutions.

Gather Information
A reliable and proactive field-service program begins with obtaining information about critical valves. The operator and the field service technicians should first complete a detailed walk-through to identify and document valve information: locations; the type, size, and dimensional data; and design and operating specifications; type of packing; and the type and scope of any repair issues.

After the walk-through, the field service technicians may need to execute a diagnostic analysis on the critical control valves. This analysis will determine the valve's actual performance and any problems with instrumentation or related equipment. Obviously, the service technicians must be both capable and versatile enough to resolve any problems with on-line equipment and correct them with the equipment and materials in the mobile unit. The field service team must be able to identify, analyze, and solve problems with the control valve, the valve's actuator, instrumentation, packing problems, and non-packing problems such as bent stems, galling in trim, diaphragm leakage, positioner problems, and calibration errors.

Should the valve fail the function test, the plant operator will be notified, and the field service technicians unit will undertake any required repairs in conjunction with the plant's production requirements. This might mean pulling and replacing the actuator, the valve, or both. It might mean something as simple as removing the packing and lantern rings to visually inspect the packing box and stem, and then repacking the valve. And in some cases, it might mean replacing, or hot swapping, the components so the plant can continue operations. All actions taken are documented and put into the equipment database.

Establish Priorities
The key to a competent, proactive field service program is prioritizing the critical service valves. Both the technicians and operator have to know and agree what components can and should be repaired in the field, and what components can be taken off line and repaired in the shop. It is not essential to send all valves to be repaired, and field service units should be capable of providing high quality inline welding and machining of valve body damage. This can also include reinstalling the motor operator and properly setting limit switches. Since the correct setting of motor actuator output torque is critical to the proper operation of motor-operated valves, state of the art equipment is utilized to test spring packs and torque switches to ensure proper adjustment and performance.

Another area in which an on-site field service team can make a positive impact is in fugitive emission control. Air quality standards have become increasingly stringent, making fugitive emissions a priority issue for plant operations. The industrial market sector spends millions annually on maintenance, downtime, and fines due to fugitive emissions.

Field service maintenance technicians can help solve this problem by implementing preventive processes that reduce emissions, implementing maintenance schedules based on process conditions, and bringing predictability to valve cycle life. Live-loaded gland packing technology and gland packing extraction can help eliminate emission concerns, while simultaneously being affordable and effective solutions for reducing costs and improving reliability.

Realize the Benefits
The benefits of utilizing the field service capabilities of a qualified repair shop with the capacity for organized and certified mobile field service for plant maintenance can be enormous. The extensive range of services offered by such vendors can provide plant operators with a wide range of options for reducing maintenance time without sacrificing production or safety especially for valve and actuator repair.

The future will only bring further advancements, and with them, an increasing shift in focus from sending parts away for repair toward self-diagnosis and field service. Inevitably, this will lead to enhanced efficiency for the industry as a whole, leaving more time for innovation, capitalization, and cost reduction strategies.

DAVID W.DOUGLAS is the president of Paradigm Services LP and CPL Control Products of Louisiana. Paradigm Service is a member of the Valve Manufacturers Association's Valve Repair Council. Reach him at 281.478.5200 or ddouglas@paradigmservices lp.com.