Sealing solutions for sterility assurance in pharmaceutical production 

Modern pharmaceutical production relies on Clean-in-Place (CIP) and Sterilise-in-Place (SIP) cycles to maintain sterility and protect product integrity. So, do current sealing technologies support these sterility standards?  

Firstly, the sealing systems used on filtration, pumps, vessels, mixers and agitators must maintain aseptic conditions and minimise contamination risks when working with challenging materials. 

Secondly, they must tolerate repeated exposure to heat, steam and aggressive cleaning agents in an industry working to the most stringent global standards of cleanliness.  

CIP and SIP challenges for sealing systems 

While other risk-averse industries share similarities, including the use of CIP and SIP, the pharmaceutical industry stands alone in treating those standards as a key principle. This creates distinct challenges for sealing systems operating in hygienic environments. 

CIP circulates heated water and chemical detergents to clean interior surfaces such as tanks and pipes without halting processes or dismantling equipment. It removes product residue, boosts hygiene and minimises operator exposure to hazards.  

SIP typically follows CIP to support sterility and kill microorganisms using saturated steam at 121°C – 134°C for at least 20 minutes. Repeating these cycles places additional strain on equipment already stressed by processing caustic materials. That is particularly true of the mechanical seal, which underpins the process integrity. Key challenges include: 

• High steam temperatures 
  Steam sterilisation exposes seals to temperature spikes and rapid cycling. This can damage the elastomers, increasing contamination risks. 

• Cleaning chemical exposure 
  CIP cycles introduce caustic, acidic or sanitising chemicals to process equipment. Seal materials must resist degradation to maintain cleanability. 

• Microbial hold points 
  Seal surfaces must be smooth, avoid the crevices that can harbour residues or microbes and support hygienic sterilisation.  

• Pressure changes 
  CIP/SIP can introduce vacuum or pressure swings. Seals must maintain integrity and remain stable to prevent leakage or process exposure. 

 Sealing solutions to support CIP and SIP  

The Type 5280 is a hygienic agitator seal for steel vessels. Modular in design, it is available in liquid-lubricated (Type 5280 W), gas-lubricated (Type 5280 G) and dry-running (Type 5280 D) versions, as well as a unique gas/dry face combination (Type 5280 GD).  

Popular in ultra-clean pharmaceutical and biotechnology applications, it applies Qualified Hygienic Design (QHD) and Good Manufacturing Practices (GMP) standards to enable CIP and SIP cleaning and sterilisation with the seal in place. This seal family includes the Type 5281 for glass-lined and the Type 5282 for special alloy vessels.  

Similarly, the Type 32 dry-running agitator seal operates without external fluid lubrication, reducing contamination risks. Well-suited to water-sensitive or dilution-sensitive applications, the Type 32 meets pharmaceutical and chemical processing standards, and the optional debris well allows for easy flushing and sterilisation. 

Seal technology for hygienic vessel and agitator applications 

Similarly, the CK series of vessel and agitator seals supports steel, glass-lined and alloy vessel designs.  

• The Type CK-725 and Type CK-726 vessel and mixer seals are designed for steel-made agitated chemical reaction vessels to DIN 28136, can switch between wet and dry operation, and offer debris well and cooling flange options.  

• Exchanging seal faces will convert the liquid-lubricated Type CK-725W to Type CK-725D, a contacting dry-running seal. 

• Similarly, the Type CK 728 is available in liquid-lubricated (W), gas-lubricated (G), dry-running (D) or a unique gas/dry face combination (GD) configuration. 

The easily cleaned, smooth profile of formed metal bellows seals, such as the Type 515H and Type GL1B, helps eliminate pockets where debris can accumulate. 

The preferred metal bellows choice for hygienic applications, the non-contacting gas-lubricated technology eliminates the need for elastomers. It is ideal for aggressive chemicals or vacuum environments and fully compatible with SIP, CIP and high-performance industrial sealing applications. 

Beyond sealing – the programmes supporting sterility  

However, implementing a single sealing solution is just part of the wider picture for those running pharmaceutical processes. Ensuring that individual mechanical seals continue to perform at the levels intended is key for technology running CIP and SIP. Support from the Seal Reliability Management Programme can help. 

These contracts are part of the John Crane Performance Plus™ modular service framework. The Managed Reliability Programme is a fully managed solution for wet seal reliability, designed for customers who want deeper, hands-on involvement from John Crane.  

With dedicated on-site engineers or technicians, the programme delivers customised service agreements with agreed KPIs and fixed fees. Meanwhile, the Reliability Support Programme is a service contract that provides targeted support for wet seal reliability. 

Customers benefit from proactive maintenance guidance, periodic field reliability support and access to John Crane’s technical expertise without the need for a full-time on-site engineer. 

 Another aspect of the John Crane Performance Plus™ modular service framework is the provision of tailored asset condition monitoring services, integrated diagnostics, focused support and actionable insights for all rotating equipment.  

Enabling monitoring through the Asset Condition Management Programme means gaining insights into asset health monitoring using vibration, thermography, ultrasound, fluid analysis, lubrication management, and emissions detection and quantification.  
 
Detecting problems at an early stage, identifying and eliminating their root causes, and implementing continuous monitoring to prevent recurrence go beyond simply identifying and developing failures to minimise their consequences. 

How hygiene-ready mechanical seals support pharmaceutical compliance 

In the pharmaceutical industry, particularly in processing, hygiene is measured in specific metrics. Pharmaceutical cleaning demands validation. The industry uses documented evidence to ensure cleaning procedures consistently remove API residues, detergents and microbes to safe levels, preventing cross-contamination in multi-product facilities.  

Combining hygienic seal designs with support systems and monitoring improves CIP and SIP success. By reducing the risk of contamination during batch changeovers and supporting increased uptime, John Crane’s hygienic, sterile sealing solutions support GMP requirements for cleanability, sterilisation and equipment reliability. The John Crane Performance Plus™ modular services framework can enhance seal longevity and, by extension, process reliability.  

CIP, SIP and productivity: How sealing strategies can bring it all together  

Most process industries depend on an always-on operation. They value maximum uptime and minimal downtime. However, the pharmaceutical industry works to more rigorous standards than most others and processes like SIP and CIP are non-negotiable.  

These intensive cycles also put additional stress on incumbent sealing solutions, and the proper sealing solutions are essential to maintaining sterility in modern pharmaceutical production. There are two core principles in enabling ongoing sterile operations for pharmaceutical processing. 

Firstly, choose a hygienic mechanical seal design that meets globally agreed standards and performs well in similar applications used by others in the same industry.