Product description
Non-invasive bubble detectors are designed to detect unwanted air or gas bubbles in liquid-filled pharmaceutical, bioprocess and medical tubing. Measurement takes place through the tubing wall, so the sensor does not come into direct contact with the process medium.
The tubing is inserted directly into the detector, allowing continuous monitoring of the fluid path without introducing an additional wetted component. Depending on the configuration, the sensor can detect microbubbles, larger gas inclusions, foam and whether the tubing is completely full or empty.
Technical overview
Bubble detection is particularly relevant in processes where uninterrupted liquid flow must be verified and unwanted gas inclusions need to be detected before they reach the next process step.
The non-invasive measuring principle keeps the sensor physically separated from the product. This avoids adding another product-contact surface to the fluid path and makes the detector particularly suitable for single-use tubing systems and other hygienic process applications.
Clear flexible tubing materials such as silicone, TPE and PVC can be monitored. Suitable reinforced transparent tubing can also be used. The detector is intended primarily for water-like or low-viscosity liquids containing little or no suspended solids.
Operating principle
The bubble detector measures through the wall of the tubing rather than contacting the liquid directly. The filled tubing is positioned inside the sensor, which continuously monitors the condition of the fluid path.
Liquid and gas have different transmission characteristics. When an air or gas bubble passes through the sensing area, the detector identifies the change and generates the configured output signal.
Depending on the sensor configuration and sensitivity setting, the same principle can be used for microbubble detection, general bubble monitoring, foam detection and full-or-empty detection of the tubing.
Because the tubing itself remains closed, the sensor can be installed without creating an additional process connection, wetted fitting or penetration into the fluid path.
Material options
The bubble detector itself does not form part of the wetted process path. Material compatibility therefore primarily concerns the tubing being monitored.
Suitable transparent tubing materials include:
- Silicone tubing
- TPE tubing
- PVC tubing
- Suitable transparent reinforced tubing
Tubing transparency, wall thickness, diameter, reinforcement and process-fluid properties should be considered when selecting the appropriate sensor configuration.
Available micron ratings
Not applicable. A bubble detector is a process-monitoring sensor rather than filtration media and therefore does not have a micron or pore-size rating.
The detector can, however, be configured for sensitive detection of small gas inclusions or microbubbles. The required detection sensitivity should be specified according to the application.
Design and construction
Non-invasive bubble detectors are available in different sizes and electronic configurations to suit different tubing dimensions and process requirements. The tubing is inserted into the sensor without requiring a separate mounting or product-contact fitting.
Depending on the selected configuration, technical features can include:
- Non-invasive measurement through the tubing wall
- Microbubble detection
- Full / empty tubing detection
- Foam detection
- Adjustable sensor sensitivity
- Integrated electronics
- Automatic or cyclic self-test functions
- Configurable electronic outputs
- Modular sensor configurations
- Optional configurations for hazardous areas
Electrical and signal options
The available sensor family supports several electronic interface options, depending on the selected detector configuration.
Available signal and communication types can include:
- TTL logic
- Serial communication
- PWM output
- PNP output
- 0–10 VDC analogue output
- 4–20 mA analogue output
- RS485 communication
Available supply voltages depend on the sensor configuration and can include 5 VDC or a wider 12–30 VDC supply range.
Compliance and hazardous-area options
Depending on the selected configuration, available conformity information includes CE and RoHS / REACH documentation. Certain detector configurations can also be supplied with an optional ATEX certificate for use in potentially explosive environments.
Exact certifications, supply voltage and signal outputs should be confirmed for the final sensor configuration.
Typical applications
Non-invasive bubble detectors are used in processes where gas inclusion, interrupted liquid supply or empty tubing could affect process control, filling accuracy or equipment operation.
- Pharmaceutical filling processes
- Fill & Finish
- Sterile filtration
- General filtration applications
- Bioreactor processes
- Fermentation
- Liquid dosing systems
- Mixing systems
- Pipetting systems
- Single-use tubing assemblies
- Fluid transfer systems
- Medical pumps
- Diagnostic systems
- Dialysis systems
- Blood handling and separation systems
Key benefits
- Non-invasive measurement: the sensor monitors through the tubing wall without direct product contact.
- Closed fluid path: no additional wetted sensor body or process penetration is required.
- Microbubble detection: suitable configurations can detect small gas inclusions in the liquid stream.
- Multiple detection functions: the sensor can also be used for foam monitoring and full-or-empty detection.
- Simple tubing installation: flexible tubing can be inserted into the sensing area without additional product-contact fittings.
- Adjustable sensitivity: sensor response can be adapted according to the application.
- Multiple electronic interfaces: digital, serial and analogue output options are available depending on the configuration.
- Suitable for single-use systems: the non-contact measuring principle allows the disposable tubing to remain the complete product-contact surface.
Configuration and quotation
The correct bubble detector should be selected according to the tubing, process liquid, required detection sensitivity and control-system interface.
For technical selection and quotation, provide the following information where available:
- Tubing material
- Tubing inner diameter
- Tubing outer diameter
- Tubing wall thickness
- Whether the tubing is reinforced
- Process liquid
- Liquid viscosity
- Presence of solids or suspended particles
- Required bubble detection sensitivity
- Microbubble detection requirement
- Full / empty detection requirement
- Foam detection requirement
- Required supply voltage
- Required electrical output or communication interface
- ATEX requirement, where applicable
- Required quantity
- Whether the detector will be integrated with a single-use assembly
If the exact sensor configuration is not yet known, tubing dimensions and a description of the process are usually sufficient as a starting point for selection.