The faulty containment valve


A case of mistaken identity?

Containment issues are becoming an increasingly important aspect of solid dosage form production, especially for highly potent and toxic active pharmaceutical ingredients (APIs) for hormone and oncology applications.

With a more intense focus on health and safety, avoiding both operator exposure and preventing cross-contamination has never been more critical.

GEA’s BUCK MC valves offer a modular, off-the-shelf solution for a variety of powder handling needs, facilitating fast product changeovers and the contained charging/discharging of potent actives from one vessel to another.

Occasionally, however, with time and use, problems can occur. Yet, working with GEA means partnering with a dedicated team of service experts. From initial project analysis, design and equipment selection to engineering, production and plant commissioning, and from operator training to entire lifecycle support, GEA’s service team and process performance experts will be with you every step of the way.

The crime: According to the customer, a top-tier pharmaceutical manufacturer with a plant in Ireland, production was being affected by what they described as a “faulty valve.”

The seals were becoming trapped and then subsequently being pulled out of their seating. More alarmingly, sections of the seal would break away and fall into the product, presenting a serious contamination risk. But, was the valve the real culprit? GEA’s David Johnson, Product Manager, Containment Technology — also known as Inspector Buck — was called in to investigate.

The investigation: Once on the scene, David’s team of experts isolated the valve and checked its function at the mill inlet without connecting it to an IBC (or mating half valve).

Every valve is fully tested at GEA during a Factory Acceptance Test (FAT) before release, so it seemed unlikely that the valve was to blame. Although the valve was actually functioning perfectly, it was at this point that a number of probable causes presented themselves regarding how the valve was being controlled.

No obvious signs of fault were detected, so the valve was operated. This is when the mystery began to unravel. The operator had to repeatedly press the open button to get the valve to open — airflow was only being supplied for 3 seconds. GEA suggests a recommended opening time of up to 15 seconds.

Furthermore, the airflow was being turned off when the actuator was in both the open and closed positions. According to GEA experts, the airflow should only be maintained when the Ebro actuator is in the open position. When closed, the airflow should be turned off to allow the actuator to spring back and allow the drive dog to return to its relaxed position.

Furthermore, as there was no back pressure remaining in the actuator, the valve was seen to be closing far too quickly and pulling at the seals. GEA advises that the opening and closing time should be 12–15 seconds to allow the rubber body seal to react as the rotating valve disc slides past.

Troubleshooting: It was not possible to adjust the flow controls on the Ebro actuator to provide the 12–15 second opening and closing time as previously described. The reason being that there was no detectable air pressure on the exhausting side of the actuator.

Positive air pressure needs to be maintained when the actuator is opened — and should therefore be present before exhausting and moving from an open to a closed position.

Conversely, when moving from a closed to an open position, the pressure within the actuator should previously have been released, meaning that the exhausting side of the actuator will need to be pressurised first.

The culprit? Although the valve appeared to be the prime suspect, it wasn’t actually the guilty party! As previously stated, the valve was not faulty at all. It transpired that the valve was not always achieving its fully open and closed position as a result of poor automation control — possibly owing to not being installed correctly.

The results varied according to how much time the air pressure had to decay after the previous operation and how many times the operator pressed the open or close buttons (for a 3 second blast) to achieve the final actuator position.

The solution: Despite being supplied with a complete operating manual and fitting instructions, not enough attention had been paid to the PI&D and FDS for the valve during installation.

The BUCK valve is an integral part of the process and, although it might be more instinctive to assume that it’s not operating correctly when an issue occurs, the cause can lie anywhere within the overall production system.

If the wheels of a car aren’t turning, it isn’t necessarily the engine that’s broken.

Although the valve appeared to be at fault, the root of the problem was found to be an installation issue.

The GEA advantage

Navigating the maze of hardware components and the huge variety of containment solutions has made it progressively more difficult to select the most appropriate equipment for the specified task: suppliers of various hardware components have developed a huge variety of containment solutions, making it difficult — even for experienced people — to decide on the optimal solution.

“GEA specialises in contained materials handling solutions for primary and secondary pharmaceutical and healthcare companies. With BUCK high containment split butterfly valves, we offer a wide range of technologies and equipment that improve and enhance the efficiency and performance of solid dosage form plants for the safe transfer of powders,” says David.

“With thousands of global implementations and more than 20 years of experience, GEA has been actively involved in many powder containment Communities of Practice, including the development of ISPE’s SMEPAC guidelines for evaluating containment equipment — now superceded by a wider ranging document titled Assessing the Particle Containment Performance of Pharmaceutical Equipment (APCPPE) — and in the latest risk-based approach to the selection of containment equipment,” he adds.

“Crucially,” emphasises David, “what sets us apart from our competitors, and gives us a unique position in the industry, is that we both own and control the containment technology we use, and we have the expertise to implement fully integrated suites and lines.”

“One of the key benefits of working with GEA is that we can supply an entire, completely integrated, containment system, from raw materials handling right the way through to tableting. We can assist and advise you to determine what level of containment is required where and when, optimising the manufacturing process and making it efficient, safe and cost-effective. We provide tailor-made containment for the pharmaceutical industry — for now and for the future,” he concluded.

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