PUPSIT in Single-Use Systems: Pinch Valve Selection and Control
Pre-Use Post-Sterilization Integrity Testing (PUPSIT) is now widely recognised as a standard expectation within sterile filtration processes. When applied to single-use systems, however, PUPSIT places additional demands on system design—particularly in relation to pressure stability, tubing behaviour, and repeatability of automated sequences.
A factor that is often underappreciated in this context is the selection of pinch valve type and actuation method. Manual, pneumatic on/off, and motor-driven proportional pinch valves each influence PUPSIT execution in different ways, and their suitability depends heavily on the level of automation and control required.
Manual Pinch Valves
Manual pinch valves remain appropriate in development laboratories, early clinical operations, and low-throughput applications. Their advantages lie in simplicity and ease of use, with direct control provided by the operator.
In PUPSIT applications, however, manual actuation introduces inherent variability. Differences in closure force and timing can affect pressure build-up and release, leading to less consistent test conditions. For this reason, manual pinch valves are generally better suited to non-critical or non-validated integrity testing activities, rather than automated or GMP-controlled PUPSIT processes.
Learn more about the ARTeVA™ Manual Pinch Valve
Pneumatic On/Off Pinch Valves
Pneumatic on/off pinch valves are commonly used in automated single-use PUPSIT systems, where repeatability and system closure are required. By removing manual intervention, these valves support closed processing, defined test sequences, and consistent operation across batches.
They are well suited for functions such as:
- Isolating filters during testing
- Controlling vent and pressurisation paths
- Executing repeatable on/off steps within automated skids
A key engineering consideration is matching actuation force to the selected tubing material. Excessive pinch force can contribute to premature tubing wear, while insufficient force may result in incomplete closure or pressure instability during integrity testing.
Learn more about the ARTeVA™ Pneumatic Pinch Valve
Motorised / Proportional Pinch Valves
Motorised proportional pinch valves provide a higher level of control and are particularly valuable where pressure ramping must be tightly managed.
By enabling gradual, controlled closure and opening, proportional pinch valves allow pressure to be applied in a more controlled and repeatable manner during PUPSIT. This can help reduce mechanical stress on both filters and tubing and supports more stable test conditions. In automated systems, proportional control also facilitates smoother transitions between process states and closer integration with pressure sensors, PLC logic, and integrity test instruments.
Learn more about the ARTeVA™ Motorized Pinch Valve
Design Considerations Common to All Pinch Valve Types
Regardless of actuation method, several factors are critical when pinch valves are used in PUPSIT workflows:
- Tubing response to repeated pinch cycles
- Actuation consistency and positional repeatability
- Control of pressure increase and release rates
- Compatibility with PLCs and integrity testing equipment
- Validation of valve performance as part of the complete filtration system, rather than in isolation
In single-use PUPSIT applications, a pinch valve functions as more than a simple open-or-closed device. Its behaviour directly affects pressure control, test repeatability, and long-term system reliability, all of which are relevant from both a performance and compliance perspective.
When designing or scaling single-use PUPSIT systems, pinch valve strategy should be considered early in the system architecture, alongside filters, sensors, and control logic, rather than treated as a late-stage hardware selection.