Intelligent sub loops optimise hygiene in purified water and WFI systems

27 5 minutes read

Key points

Listen to this article

Maintaining hygienic flow conditions in purified water (PW) and water for injection (WFI) systems is one of the biggest challenges facing pharmaceutical manufacturers. In particular, preventing biofilm formation within point of use (POU) sub loops is essential for maintaining product quality, regulatory compliance and process reliability.

Traditional approaches, including monitored T-valve systems, cannot guarantee consistently hygienic flow conditions, whilst the geometry of many conventional Coriolis flowmeters is not specifically designed for hygienic pharmaceutical applications. By integrating an intelligent, fully automated sub loop with hygienically optimised flow measurement and advanced valve technology, pharmaceutical manufacturers can achieve controlled circulation, highly accurate dosing and significantly reduce the risk of biofilm development.

Bürkert’s Segment Manager for Hygienic-Pharmaceutical, Damien Moran, explains.

Why sub loop flow management matters

Within a pharmaceutical manufacturing facility, purified water and water for injection distribution systems deliver ultra-pure water precisely where it is required. The primary distribution loop continuously circulates water to maintain hygienic conditions throughout the system.

From this continuously circulating main loop, dedicated sub loops are commonly installed to supply individual production areas, processing equipment or manufacturing skids. While this approach provides operational flexibility, it also introduces an important engineering challenge.

Flow conditions within each sub loop must remain consistent. If circulation becomes demand-driven or is influenced solely by conditions within the main loop, flow velocity may reduce significantly, stop altogether or even reverse direction. Any of these conditions can compromise the quality of PW or WFI.

Although ultra-pure water systems are carefully designed and maintained, trace bacteria can still enter through microscopic leaks, cracks or contamination introduced during maintenance activities. Once bacteria enter a poorly circulating sub loop, inadequate flow conditions can encourage biofilm formation. Effective flow management therefore becomes critical in maintaining hygienic operation.

The limitations of manual control

One option for managing sub loop flow is manual control. This approach is more commonly found in purified water applications than in water for injection systems, where significantly higher levels of precision are required.

However, manual operation inevitably introduces inconsistencies. Operator-dependent flushing volumes create undefined quantities, particularly where direct flow measurement is unavailable at individual points of use. This can result in unnecessary water consumption through excessive flushing or, conversely, increased hygiene risks if insufficient flushing occurs.

Achieving consistent performance with manual methods relies heavily on operator training, experience and careful process control.

Some facilities attempt to reduce biofilm risk by installing a manual T-valve system with a simple branch to the point of use instead of incorporating a continuously circulating sub loop. Whilst this arrangement can reduce the likelihood of biofilm development, it cannot eliminate the hygiene risk.

Flow through the dosing branch remains dependent on user demand and manual operation, meaning it is still undefined, inconsistent and intermittent. Even when flow monitoring is added to a T-valve system, contamination risks remain because dead legs and stagnant sections within the dosing line cannot be completely removed.

Surface Acoustic Wave technology improves hygienic flow measurement

A more effective solution is the integration of an intelligent sub loop capable of maintaining continuous, optimised flow conditions.

At the centre of this approach is the flowmeter. For pharmaceutical water applications, the ideal instrument measures flow velocity and volumetric flow rather than simply monitoring mass flow. These parameters directly influence the hydraulic conditions needed to prevent biofilm formation.

Equally important is hygienic design. A straight tube geometry helps minimise dead legs whilst making cleaning procedures more effective and reliable.

Surface Acoustic Wave technology provides an effective method of achieving highly accurate flow measurement whilst supporting hygienic system design.

The technology measures the time difference between acoustic waves travelling along the surface of the measuring tube. These differences are directly proportional to the flow of purified water or water for injection through the system.

This measurement principle enables continuous monitoring of key indicators associated with biofilm prevention, including:

Real-time volumetric flow
Cumulative volume
Flow velocity
Temperature

Because the Surface Acoustic Wave sensors are mounted externally on the tube rather than positioned within the flow path itself, the potential for biofilm development is further reduced.

Hygienic flow measurement with FLOWave

Bürkert’s FLOWave flowmeter uses Surface Acoustic Wave technology to deliver dosing accuracy of up to 0.4% of the measured value, with repeatability of 0.2% deviation.

This level of precision helps maintain sufficient turbulence within PW and WFI sub loops, supporting hygienic operation whilst delivering highly accurate dosing performance.

Manufactured from 316L stainless steel, the internal surface of the Bürkert Type 8098 FLOWave flowmeter has an average surface roughness (Ra) of less than 0.4 µm. This highly polished finish reduces microscopic surface imperfections where biofilm could otherwise establish itself.

The flowmeter is also fully compatible with clean-in-place (CIP) and sterilise-in-place (SIP) processes, making it well suited to pharmaceutical manufacturing environments.

Advanced 2-weir valve technology

Alongside accurate hygienic flow measurement, valve performance plays a crucial role in maintaining consistent sub loop operation.

A typical point of use sub loop requires two separate valves: one to maintain continuous circulation through the sub loop and another to control dosing at the point of use.

By using a multi-way diaphragm valve, both functions can be combined within a single compact valve body.

Bürkert’s pneumatically operated Type 2036 Robolux multi-way diaphragm valve uses innovative 2-weir technology, incorporating two independently controlled valve actuators within one housing.

Its rapid switching capability allows flow to be redirected almost instantly, improving dosing accuracy whilst maintaining uninterrupted circulation through the sub loop.

Developed specifically for hygienic applications, including purified water and water for injection systems, the Type 2036 incorporates flow-optimised internal geometries that eliminate dead legs and improve self-draining characteristics.

Like the FLOWave flowmeter, the valve is manufactured from 316L stainless steel and is fully compatible with CIP and SIP cleaning procedures.

Intelligent automation delivers greater process control

Bürkert’s point of use solution is fully automated, providing significant improvements in precision, repeatability and operational control.

Accurate automated control ensures consistent dosing whilst maintaining the flow conditions necessary to minimise biofilm formation throughout the sub loop. This intelligent level of control supports pharmaceutical quality standards, regulatory compliance and comprehensive process documentation, particularly within demanding WFI applications.

Automation also improves the efficient use of purified water and water for injection by eliminating unnecessary wastage during operation.

In addition, the system is considerably easier to operate than manually controlled alternatives. Reduced operator intervention saves time, lowers training requirements and decreases dependence on highly skilled personnel.

The solution can be integrated directly with a PLC or operated as a standalone system using a local display. Flexible automation modules and communication protocols enable the creation of a fully automated control loop suited to a wide range of pharmaceutical manufacturing environments.

Optimising pharmaceutical water distribution

As pharmaceutical manufacturers continue to demand higher standards of hygiene, reliability and efficiency, the design of purified water and water for injection distribution systems continues to evolve.

Although sub loops present additional design challenges, combining hygienically optimised components with intelligent, measurable flow control provides a highly effective solution for reducing biofilm risk and maintaining consistent point of use performance.

For purified water systems, this approach delivers improved efficiency and process control. For water for injection applications, where hygienic performance is even more demanding, intelligent sub loops represent a next-generation solution, delivering continuous circulation together with accurate, repeatable extraction whilst helping maintain the highest standards of pharmaceutical water quality.

For further information, visit www.burkert.co.uk

Contact Details About Us Latest News Latest Videos

Burkert Fluid Control Systems

01285648720
sales.uk@burkert.com
http://www.burkert.com/
Fluid Control Centre 1 Bridge End Gloucestershire Cirencester GL7 1QY GB

About us

Bürkert is present in thirtyfive countries around the world. We also work with a large network of distributors and partners, which means we are as close as possible to our customers. This global presence ensures full service and support to all of our customers in every country around the world. Research is the lifeblood of our company.

At Bürkert, we are never satisfied with the status quo and are continually seeking new technologies and solutions for our customers. Every year, our people develop new and highly advanced products and solutions, ranging from integrated process measurement and control units to the most sophisticated systems used in pharmaceutical research. To be a market leader, we are also an R&D leader.

Therefore, our investment in research & development is one of the highest in our industry. In our research centres in Germany and France, 150 people are committed to working for a common future for our company and our customers. We are committed to offering our expertise wherever it is needed, anywhere in the world. This global presence ensures that our advances in fluid control technology are also global.

What we do in a nutshell

Manufacture of process equipment. One of the few manufacturers to provide solutions for the complete control loop.

Where we supply to

UK Ireland, Europe

Industries we supply to

Food and Beverage, Pharmaceutical Cosmetics Toiletries, Water and Wastewater

Intelligent sub loops optimise hygiene in purified water and WFI systems

Maintaining hygienic flow conditions in purified water (PW) and water for injection (WFI) systems is one of the biggest challenges...
Reducing Fluid Control and Automation Complexity in Pharmaceutical Process Development

Designing and building pharmaceutical processes and skids requires close collaboration between mechanical, electrical and instrumentation, and automation engineering teams. Yet...
Cutting Data Centre Cooling Energy Use by Up to 80% with Advanced Solenoid Valve Technology

Greg Wainhouse, Regional Business Development Manager – Industrial Water, North Europe In modern data centres, direct-to-chip liquid cooling has become...
Bürkert Solves Tank Pressure Drift with Sub-200 ms Gas Control for Hygienic Applications

Maintaining precise tank pressure is critical across food and beverage, pharmaceutical and biopharmaceutical manufacturing. Even small pressure fluctuations can affect...
Media separated pressure relief valve protects components and optimises control

Flow control specialist Bürkert has introduced a new pressure relief valve designed to protect sensitive components in fluidic systems from...
Smart sensors safeguarding water quality in food manufacturing

Water remains one of the most critical resources in food processing and manufacturing. From ingredient blending and product washing to...