Automated tests improve valve monitoring on remote installations

Emergency shutdown (ESD) or emergency venting (ESV) valves are used to shut down or vent critical systems and min-imize the chance of fire or explosion during a severe process upset. However, when valves are rarely cycled, there is always concern over whether they will work when needed. - The ValvGuard testing and monitoring system automatically monitors availability of the valve's electrical and pneumatic components in real time.

By increasing the testing frequency and analyzing the test results, a higher level of diagnostic coverage can be achieved. The testing interval and diagnostic coverage influence the process safety engineer's calculation of the probability-to-fail-on-demand value. Put simply, if the valve can be partially operated it is far more likely that it will also move during an emergency situation, without being damaged - just like human muscles.

There are various ways to test a valve's availability. The best way to test on-line has been with a mechanical jammer device. Technicians attach such a device to each emergency valve. The jamming device allows the valve to move minimally. A signal is then sent from the control room to see whether the valve will cycle. But there are significant gaps in this partial stroke-testing approach.

Manual testing does not provide real-time information on the valve's operability, except at the time of workshop testing. It also confirms if a valve is working at a given point of time, but does not verify how well it is working or if it is starting to fail. And it provides little, if any, information on whether the valve needs maintenance conventional emergency valve testing is problematic at unmanned operations such as offshore installations, since technicians must be transported to the site. At some plants, the cost of manual emergency valve testing exceeds $1 million a year. In light of this, it is impractical to increase the frequency of manual testing.

A intelligent, automated, standalone testing and monitoring system for emergency valve applications eliminates much of the gaps associated with manual partial stroke testing, and dramatically reduces associated manpower costs. Neles' ValvGuard system allows for two types of remote, automated ESD/ESV system testing:

• The automatic valve test partially exercises the valve as much as the process will allow (e.g. 20%) to assure it is capable of stroking
• The pneumatic test assesses availability of the emergency system, including the pneumatics of the ValvGuard field device, piping electrical circuits and connections, without actually cycling the valve.

Test procedures are part of the on-board intelligence of the device and are performed independently. They can be monitored remotely on Valve Manager software and the results stored in the remote database.

Emergency valve tests are performed automatically with results recorded remotely at user-selected intervals (daily, weekly, monthly). As a result, information on the valve's readiness is always current. While testing the valves, the system continuously sends information on the ESD/ESV condition and status. This provides added assurance that final elements in the safety loop are operational.

Unlike conventional emergency valves with mechanical jamming devices, the intelligent valve system is always ready for operation. This provides an extra margin of safety and may eliminate use of back-up valves for safety testing. Powerful valve management software analyzes current emergency valve test data and trends on line (i.e. actuator load factor). Maintenance is planned before an unacceptable risk of valve failure should arise. This also lowers costs by eliminating unnecessary maintenance.

Tests are fully automated and condition monitoring is conducted from a remote location using Hart protocol. A technician's presence is not required at the valve during the test procedure, making it ideal for remote offshore installations. Also, new configurations or additional tests can be performed remotely from a cross connection room.

One-year long tests in two refineries, one steel mill and one chemical processing plant in Finland confirm that ValvGuard is a highly reliable, intelligent safety technology. After more than 200,000 hours of continuous testing, not a single system failure or failure of any of the system's components was detected.

Aker Rauma Offshore

Aker Rauma Offshore specializes in offshore construction projects worldwide, using the most advantageous construction sites and sub-contractors to maximize cost efficiency. Products and services include turnkey offshore contracts, engineering and construction contracts, contract management, engineering and feasibility studies and procurement and logistics services. These are offered for Spar platforms, offshore exploration rigs, floating and jack-up production platforms.

Junttan

Junttan was founded in 1976 to manufacture hydraulically driven, special equipment for foundation works. Its main products are hydraulic piling hammers and hydraulic piling rigs. Additionally, it manufactures rotary heads for bored piles and hydraulic power packs. The company claims to be Europe's leading manufacturer of hydraulic piling rigs, and the world's biggest manufacturer of hydraulic hammers. Its products are used in over 40 countries, and its distributor network covers the main markets in Europe, Asia and the Americas.

Larox Flowsys

Larox Flowsys has supplied Larox valves for abrasive and aggressive on/off and control applications to various drilling and production platforms over the past few years. Applications for the valves include bulk and mud handling, drilling mud, cement and bulk carriers, produced water, cyclones and hydrocyclones, underwater sandblasting, seawater, sanitary service and sewage treatment. Larox Beta is a new pinch valve designed for use in slurry and waste handling. The company's valves are manufactured according to ISO 9001 and I they also have DNV Type Approval for offshore and ship use.

Rautaruukki

Rautaruukki is a large-scale steelmaking and upgrading company. The operations of the Rautaruukki Steel division are further divided into two business areas - plate products and strip products. The plate products business unit produces hot-rolled plates, pre-fabricated plate products and plate components. Pre-fabrication operations include surface treatment, cutting into shapes, precision cutting, bending, beveling and cutting into wide flats. Plate components include dished and flanged ends, longitudinally welded heavy tubes and sections. Rautaruukki also claims to be one of Europe's leading steel producers in terms of profitability, productivity and energy consumption efficiency.

Straightway Marketing

Straightway Marketing promotes the trade route via Finland to and from Russia and the Former Soviet Union countries. It represents two ports, 25 logistics companies and three regional development companies. It also offers free advice on logistics, services, and investment opportunities in southeast Finland. Straightway's services include advertising, network marketing, company visits, an internet site (www.straightway.fi), trade fair participation and trade missions, and contact forums.

Vacon

Vacon specializes in frequency converters. The company claims to be the most rapidly growing manufacturer in its field. The company's products range from 0.55 kW to 1.5 MW, covering all voltages and IP classes and complying with all EMC directives. They can be fitted easily to pumps, winches, thrusters, lifts and cranes. Vacon also supplies DC-fed drives for cable-laying systems as regenerative drives. The product range covers both sensorless vector and closed loop vector control as well as numerous fieldbus communication cards.