Archive | Control Valves

18

3:16 pm
August 14, 2017
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Select The Best Seats for Your Butterfly Valves

randmButterfly valves owe much of their popularity to their economic cost and efficient designs. Among the butterfly valves available in today’s marketplace, the resilient-seated type (the most basic) is the design that’s commonly used in fluid-processing applications.

According to the fluid-handling experts at Crane Engineering (Kimberly, WI), the functionality of a butterfly valve is greatly dependent on its seat, which seals between the pipe flanges and the valve disc. In resilient-seated designs, the stem is centered in the middle of the valve disc that, in turn, is centered in the pipe bore. These valves typically feature a somewhat-flexible seat and rely on the disc for a high level of contact with the seat to ensure a proper seal.

Seat-Type Pros and Cons

Three basic seat styles are available for resilient-seated butterfly valves. A recent post on the Crane Engineering blog discussed the pros and cons of each, including their specific strengths and weaknesses. (Use Table I for quick reference.)

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1708rmcfluidhandling01dBooted (dovetail) seats. These seats have a dovetail shape that mates with the inner-diameter valve bodies. They’re easily removable and serviceable because the fit isn’t physically bonded. Unfortunately, they’re prone to movement when mounted between flanges, resulting in deformation that tends to bulge around the disc-contact points. This sensitivity to mounting conditions limits the versatility of booted-seat butterfly valves. Molded and cartridge seats were developed to address such weaknesses.

1708rmcfluidhandling02dMolded seats. These seats are bonded to the bodies of valves through an injection-molding process. While this provides a direct bond, it makes the seat irreparable. Since the seat is integrated with the valve body, the entire valve must be replaced if the seat becomes damaged. Still, a molded seat’s permanent bond with a rigid valve body has advantages over a booted seat. Molded-style seats also resist deformation and dislocation during valve mounting and are capable of dead-end or vacuum service.

1708rmcfluidhandling03dCartridge seats. These seats are created by compression molding a layer of elastomer onto a rigid phenolic backing ring, which supports the elastomer in multiple directions. This process is much more consistent than the injection molding used to create molded-style seats. It provides constant pressure to form the seat shape and maintains tight control of its dimensions. Because of the tight tolerances, cartridge seats offer the best torque consistency and highest wear resistance. This type of seat also improves upon the molded style by making the seat replaceable. In highly abrasive applications, i.e., where valves need to be replaced on a regular basis, the cartridge seat could simply be replaced rather than the entire valve.

Cartridge seats offer advantages unmatched by other seat styles. When the valve body has an integrated retaining lip, a cartridge-seated valve is capable of dead-end service. Unlike booted or dovetail seats, cartridge seats can more efficiently operate in a system that requires vacuum service.

Update Your Valve-Speak

To learn more about general valve terminology, download Crane Engineering’s  “Ultimate Glossary of Valve Terminology”. MT

Crane Engineering is a distributor of industrial-grade pumps, valves, filters, wastewater-treatment equipment, and other fluid-processing technology. Services include repair, corrosion-resistant coatings, and skid-system design and fabrication. For more information and instructional videos, visit craneengineering.net.

75

7:33 pm
June 28, 2017
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Multitasking Valve Combo

1707mtprod11pThe Hybrid Valve is a combination pulsation dampener and back-pressure valve. As a single unit, the valves takes up less space and has fewer leak points. According to the company, when installing pulsation dampeners and back-pressure valves in any pumping system, location and proximity is key. A back-pressure valve installed in series with a dampener can negate the dampening effect if the valve is opening and closing before the dampener is able to capture a full pulse. This quick-opening effect can also create too much gain within the back-pressure valve resulting in inefficiency and chatter. The hybrid valve, as a single unit, eliminates common issues and produces a simplified system.
Blacoh
Riverside, CA
blacoh.com

3217

6:19 pm
July 8, 2014
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Interlock Technology Improves Process Safety in Tanker Loading/Unloading Operations

image009Kirk Key’s (Kirk) Eagle Series interlocking products provide process-safety control in tanker loading and unloading operations. The company’s trapped key interlocking systems ensure that users follow a pre-determined sequence of operation for activating road, rail, and sea tanker control valves in oil refining, petro-chemical, pulp and paper, liquefied gas and other industrial applications. Kirk Eagle Series valve interlocks integrate with its mechanical and electromechanical trapped key interlock series to form a comprehensive safety scheme.

According to the manufacturer, product-transfer procedures that rely on manual control can lead to spills or leakage of hazardous gases or liquids, causing injury, property damage and potential fines. By controlling a defined sequence of equipment operation, such hazards are minimized.

The company says its interlocking systems are designed to site requirements and ensure that safety processes move smoothly across a range of equipment including road, rail or marine barriers, hoses, gantry accesses, valves and pump electrical switches. Each step in the scheme releases a uniquely coded key required to move safely on to the next step of the sequence. These oversized keys can’t be duplicated and the sequence can’t be circumvented.

The Eagle Series includes integral valve interlocks to fit every type and size of quarter and multi-turn valves, as well as bolt and electro-mechanical interlocks. To support long-term use in harsh environments, all Eagle Series products are manufactured entirely of 316 stainless steel and incorporate keyways that are protected by a gasketed flip covers.

3105

4:28 pm
June 9, 2014
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High Integrity Safety System Works Alone or With Any DCS, PLC or HMI

Screen Shot 2014-06-09 at 11.07.08 AMABB has released its High Integrity (HI) safety system for use with any ABB or third-party control system, PLC or operator interface. This TÜV certified release lets users leverage the system for any SIL 1-3 application and to interface all necessary information to the existing control system and/or operator interface.

The offering includes an object-oriented engineering environment with SIL certified safety libraries that efficiently support reuse and engineering throughout the entire safety lifecycle. The engineering environment includes IEC 6113103 programming languages and the easy to use Diagram Editor as well as safeguards against non-SIL compliant configurations.

Core functions include system security, access control, confirm operations, force control, time-tagging to millisecond accuracy, audit trail, system diagnostics and difference reporting, all of which provide an extra layer of authentication for maintenance bypasses and force control, as well as enhanced capabilities for troubleshooting and root-cause analysis.

According to ABB, its new Independent High Integrity system is well suited to applications where deep integration with the process-control system isn’t required, such as relay replacements or systems where visualization is provided by an ABB or third-party process panel, simple HMI or control system. The HI hardware and engineering tool are also used with ABB’s Freelance and Symphony Plus control systems to deliver safety solutions that are SIL3 certified to Edition 2 of the IEC safety standards

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