A primer in valve technology

The adhesives and sealants industry relies heavily on valves to control the flow of fluids in the formulation and application of its products. Valves are a critical link in the processing systems used for adhesives and sealants, as are the actuators that control them.

It is safe to say that no matter what valves are used in adhesives and sealants processing, they are only as good as their controlling actuator. While electronic valve actuators have long been an integral part of process applications, improvements to these actuators are making them more cost-effective, versatile and user-friendly than ever. New "smart" electronic valve actuators can save significant time and money by increasing safety and efficiency, reducing maintenance costs, and improving the quality of the final product.

Electronic actuators, such as the Flowserve Limitorque MX, are able to operate under the harshest conditions while maintaining predictable, reliable and safe operation. For large-scale operations, hundreds of actuators can be linked together in a network and accurately controlled from one central location, providing reliable automation of complex plant processes.

How They Work

At the most basic level, electronic valve actuators use an electric motor to open and close a valve. This sounds simple enough, but in plants, where hundreds of valves are opening and closing independently in response to conditions that are changing in real time, things can get complicated rather quickly.

To solve this problem, smart actuators are networked through a host controller, which receives diagnostics information from flowmeters, pressure gauges and other sensory equipment in the plant. The host controller uses this data to operate the actuators to achieve maximum system performance. Host controllers can be external distributed control systems (DCS), programmable logic controllers (PLC) or personal computers. They can communicate with as many as 250 actuators at a time through a proprietary device, like the Flowserve Limitorque Master Station II, or through devices that use common communications protocols, like FOUNDATION Fieldbus, Profibus and DeviceNet. Smart actuators send information back to the controller, creating true back-and-forth communication between all components of the system.

This sophisticated communication technology demonstrates the level of complexity today's valve actuators offer. Not only do they open and close valves, they must also be able to move them to any intermediate position with great accuracy by acting on signals from the host controller through the network. These actuators are also relied on to provide preventative maintenance data and enhanced safety for process operations.

Increased language options, better display features and improved interfaces make modern electronic valve actuators easier to use and more compatible across platforms and equipment. New models even offer optional Bluetooth wireless connectivity, and allow diagnostic information to be easily transferred to a PDA, laptop or cell phone.

MX Actuators in the Adhesives and Sealants Industry

In the adhesives and sealants industry, hazardous materials are transported and dispensed at high temperatures and varying viscosities. Because of this, it is crucial to ensure both precision and safety. The Flowserve Limitorque MX smart electronic actuator provides dependable, safe and accurate valve control under the most extreme conditions, even those found in adhesives and sealants manufacturing.

Smart electronic actuators have built-in safety and control measures for conditions that can be hazardous to personnel or to the environment. For example, the MX includes Built-In Self Test (BIST), a state-of-the-art controls platform that verifies and validates the integrity of its components. Safety features like BIST enable companies to conform to higher safety standards, in this case aiding them in meeting the Safety Integrity Level (SIL) requirements of IEC 61508. The MX's ability to detect potential equipment failures before they occur also lowers maintenance and line shutdown costs, creating a safer and more efficient environment for personnel.

Since uniform conditions and material purity are necessary to formulate and apply high-quality adhesives and sealants, valves must operate precisely and accurately. With built-in positioning systems, such as the MX's absolute encoder, smart actuators ensure that valves are opened to exactly the right position at exactly the right time, thereby avoiding errors or leakage, and eliminating inconsistencies in the final product.

The MX also features MX QuikTM, an uninterrupted power transfer option that prevents unexpected shutdown during main power losses. The MX is configurable for up to one hour of Quik power, which is recharged for the next unforeseen power outage once main power is restored. No batteries are required for this process. Without this feature, the actuator would have no way of switching to fail-safe mode and carrying out its safety procedures, which could be catastrophic to the equipment and the safety of plant personnel.

Choosing the Right Actuator

When choosing the right electronic actuator for a particular adhesives or sealants application, factors to consider include cost, safety and ease-of-use. The best actuator for the job will increase productivity and efficiency while decreasing maintenance costs and downtime. Actuation systems that are too complex for a particular application are wasteful, and inadequate equipment may be even more devastating to plant operation and safety.

Electronic actuators are available in a range of size and torques, and are configurable for multi-turn and quarter-turn applications to accommodate many different valve sizes and types. Smart valve actuators like the Flowserve Limitorque MX provide many benefits to companies that need tight control of their process applications. With torques as much as 1700 ft-lb (2307 N m) and thrust ratings reaching 75,000 lb (333 kN), the MX offers a full range of service to processing operations in the adhesives and sealants industry.

Flowserve Corp. is one of the world's leading providers of fluid motion and control products and services. Operating in 56 countries, the company produces engineered and industrial pumps, seals, and valves, as well as a range of related flow management services.

For more information, contact Earnest Carey, Product Management manager, Flowserve Flow Control, Limitorque Actuation Systems, phone (434) 522-4107, e-mail ecarey@flowserve.com , or visit http://www.flowserve.com .