John Crane Seal Provides New Solution for High Temperature and Corrosive Environments.

MORTON GROVE, Ill. -- John Crane -- the world's leading supplier of engineered sealing systems and associated products -- has announced the introduction of a new generation of dependable High Temperature Corrosive (HTC) resistant mechanical seals that utilize an innovative design technology to reliably seal high-temperature process fluids on rotating equipment. Proven on difficult applications at a number of the worlds largest oil refineries, these seals will extend the Mean Time Between Repairs (MTBR) as compared with conventional seals in high-temperature and extremely corrosive environments.

According to Jesse Fordyce, Market Manager at John Crane, the industry has long sought a better solution for corrosion-resistant high-temperature sealing applications because today's refineries are using sour crude that is high in sulfur content. Sour crude is full of organic acids that, when refined at high temperatures, creates naphthenic acid, which is extremely corrosive to certain metals. Damage is evident in the form of unexpected high corrosion rates on alloys that would normally resist sulfidic corrosion. Sulfur, at a level of 0.2 percent and above, is known to be corrosive from 230 degrees Celsius (450 degrees Fahrenheit) to 455 degrees Celsius (850 degrees Fahrenheit). This corrosive nature requires companies to spend significant dollars on replacing pumps, valves, piping and seals that become damaged by corrosion.

Traditionally, coating the exposed metallurgy in high temperature welded seals with various platings was a method to combat naphthenic acid attack. However, these practices typically only delay corrosion since the plating can flake-off, which exposes the base metal and corrosion begins.

Corrosion-related issues regarding processing, particularly at elevated temperatures, coupled with increasing regulation pressures, have forced refineries to implement defensive strategies to mitigate corrosion issues and search for technologies that can provide for longer service life of equipment.

To combat this corrosion at high temperatures, John Crane engineered the Type 604HTC and Type 609HTC high-temperature corrosion-resistant welded metal bellows seals to provide reliable sealing of fluids in harsh high-temperature corrosive environments as well as providing superior seal face stability at elevated temperatures.

"The Type 604HTC and 609HTC seals use all-Inconel metallurgy and unique face seal technology that provides exceptional seal face stability and is able to adapt to a wide-range of temperature extremes found in high-temperature corrosive environments," said Fordyce. "The all-Inconel seal eliminates the need for platings and can extend MTBR."

The HTC seals utilize a complete Alloy 718 construction that is resistant to corrosive attack and retains its high strength at higher temperatures. Alloy 718 is the highest strength metal bellows material currently available.

Beyond corrosion resistance, the Type 604HTC and 609HTC seals offer exceptional face stability. The HTC seal controls face distortion by incorporating an innovative seal face design. Controlling seal face distortion is an effective means of ensuring seal reliability and the HTC is designed in such a way that face flatness changes very little with changes in temperature and pressure. The exceptional face stability from this design results in reduced leakage and potentially longer seal life. Even if the application is not corrosive, the extra face stability provided by the seal can extend MTBR.

"The HTC seals have shown to be superior for high temperature metal bellows seals with high corrosion resistance for applications up to 425 degrees Celsius (800 degrees Fahrenheit)," said Fordyce.

Two HTC seal options are available. The Type 604HTC is a high-temperature corrosion resistant stationary bellows assembly that is capable of handling high shaft speed applications and high shaft-to-seal chamber misalignment. The Type 609HTC is a high-temperature bellows assembly intended for those demanding applications where a dependable, high-strength, rotating seal is preferred. Typical applications for these seals include hydrocarbons, aromatic fractionation products, crude oil fractionation products, heat transfer fluids as well as chemicals, caustics, some acids, aqueous solutions and lubricating liquids. The narrow radial cross-section fits most popular pump models without modification.

The API 682 (ISO 21049) qualified HTC seals are available in both stationary and rotating configurations, as well as single and dual seal arrangements. Further, the HTC seal is capable of both Inside Diameter (ID) and Outside Diameter (OD) pressure with the ability to withstand reverse pressurization. Full reverse capability provides process containment safety against system upsets on dual seal systems.

About John Crane

A member of the Smiths Group, John Crane (www.johncrane.com) is the acknowledged technology leader and the world's largest manufacturer of mechanical seals and associated products. With a workforce of over 6,000 people in more than 50 countries, John Crane provides an unrivalled global presence combined with personalized local service and support. John Crane offers a comprehensive range of engineered mechanical seals and sealing support systems, mechanical packing, power transmission couplings and centralized lubrication systems under the brand names John Crane, Sealol, Safematic, Flexibox, Metastream, Powerstream, and Lemco. These products are sold widely into rotating equipment applications in petroleum, chemical, pharmaceutical, pulp and paper, power generation, food and beverage, mining and minerals, transportation, industrial, water and waste, refrigeration, automotive, as well as appliance markets.