Chemical processing: Mechanical seals – where sustainability starts

Businesses involved in chemical processing are under increasing scrutiny to meet ever-stricter environmental regulations.

Meanwhile, reducing emissions, conserving water and improving efficiency are key to meeting business and corporate sustainability targets.

Chemicals – challenging and complex

It is these unique demands that make the chemical industry one of the most challenging environments for process technology.

In response, John Crane has engineered sealing technology to support the management of fluids, gases and raw materials in extreme environments.

Our mechanical seal and support system choices can help improve business outcomes and make operations more sustainable as a welcome by-product.

Because, for chemical industry customers, every mechanical seal is a business-critical component, and selecting the most reliable solution for your operational profile is a crucial strategic decision.

Selecting the appropriate mechanical seal can help prevent leakage, support process infrastructure efficiency and minimise emissions. An unsuitable choice, by contrast, can lead to downtime and lost productivity.

We have been at the forefront of sealing innovation since 1917, when engineer John Crane repaired a leaking radiator heating pump, earning our first patent. Since then, helping our customers operate more sustainably by choosing the appropriate mechanical seal and seal support system has been a core business principle.

John Crane: Supporting sustainable chemical processing

Our advanced mechanical seals and seal support systems enable chemical industry customers to operate more effectively and sustainably by reducing the need for flush water and cooling systems, conserving water and lowering energy consumption, enhancing sustainability and improving business outcomes. There are many options, each suited to a specific use case.

Mechanical seals

Popular, cost-effective and reliable, our elastomer bellows and component mechanical seals create a self-aligning seal around rotating shafts in challenging environments. Ideal for low-pressure, non-corrosive chemical processing applications, to address specific operational issues in large rotating equipment.

Designed for controlled sealing environments, our high-performance, low-emission cartridge seals enhance safety for rotating equipment in hazardous environments. They can be used plant-wide to simplify inventory and maintenance, offering maximum control in complex sealing applications.

John Crane edge-welded metal bellows products, such as the Type 670 and Type 609, as well as our Type 515 formed metal bellows seals, are available in both single- and dual-seal arrangements, with seal faces and metallurgies that suit both high- and low-temperature applications. Meanwhile, the Type 285 seal is ideal for sealing cryogenic liquified gases.

Secondary containment

As a core principle, John Crane mechanical seals help prevent hazardous fluids, volatile organic compounds and fugitive emissions from escaping from the rotating equipment so integral to chemical processing.

However, the chemical industry is naturally risk-averse. Therefore, some operators deploy a secondary containment seal, often an outer seal in a dual-seal configuration, to help reduce fugitive emissions and to function as a safety backup.

Technologies such as the patented, non-contacting, bi-directional seal face pattern on the Type 28SCB help contain leakage, reducing hazards from buffer fluid contamination and eliminating the problems associated with disposing of contaminated fluid.

Dual mechanical seals

A buffer or barrier fluid system helps our dual mechanical seals, such as the first truly universal cartridge seal, the Type 5620 and Type 5620P, as well as the Type 5625 and Type 5625P-1 metal bellows seals, achieve near-zero emissions.

Similarly, non-contacting, gas-lubricated, dual-cartridge seals, such as our Type 2800E, can achieve zero-emissions, eliminate the costs associated with wet seal systems and significantly reduce energy consumption.

A dual seal arrangement is often specified as the seal arrangement of choice for challenging process fluids and includes products such as our ECS, 48SC and 28LD secondary containment seals.

Split seals

Ideal for both small and large rotating equipment in chemical plants, our split mechanical seals simplify seal installation and reduce downtime by eliminating the need to decouple the pump shaft or dismantle pumps or other rotating equipment. Split seals are commonly used on benign fluids such as water services.

Examples include the Type 3740 and the dry-running Type 3740D. Innovations such as the Type 73 provide an inflatable backup that enables safe primary seal installation, such as with horizontal transfer pumps on storage tanks.

Vessel, mixer and agitator seals

Available in single and dual seal configurations, with wet-running, dry-running and gas-lubricated seal arrangements, our vessel, mixer and agitator seals create reliable barriers in mixing and agitation processes for steel and glass-lined vessels. Maintaining process integrity and complying with industry standards as ATEX, DIN and ISO.

Our Type 32 is a single, dry-running elastomer O-ring mixer and agitator seal that requires neither external cooling, lubrication equipment nor a supply system. The series includes specialist variants, such as the Type 32D, designed for use in explosive atmospheres and the Type 32i, which features our unique Intelli-Face® seal face technology.

Meanwhile, the Type 7800 Series is a modular cartridge seal designed for use in a wide range of mixing and agitating equipment, covering a broad spectrum of chemical applications. The Type 7848W is a conventional wet-running seal that requires an external liquid for lubrication, while the non-contacting, gas-lubricated seal faces of our Type 7848D feature our spiral groove technology, offering robust emissions protection.

John Crane created the Type CK series of dual-pressurised cartridge seals for top-entry mixing and agitating equipment. While the wet, pressurised barrier liquid version of the Type CK 725W suits undemanding applications, converting it to a contacting dry-running seal creates the Type CK 725D, suitable for operation in potentially explosive atmospheres.

In our next blog, we'll examine the seal support systems, couplings and services that customers in the chemical industry rely on to ensure their processes operate as intended, regardless of the materials' aggressiveness, temperature or pressure.

In the meantime, visit our case studies page to see how our solutions support the chemical industry in the real world.