Safety in the clean room
Solutions for ensuring safety through: Pressure transmitters in clean room monitoring systems.
Stable air pressure is important in clean and hygienic rooms to avoid contamination. It reduces disturbances in the air and generates the desired air flows. The air is purified via various filter systems and either a permanent positive pressure or negative pressure is generated. This technology is used in a variety of manufacturing processes, e.g. in the semiconductor industry, food technology and pharmaceuticals. The protection of people and products must be guaranteed for compliant cleanroom systems. Our pressure transmitters support you in this by enabling reliable measurement thanks to their innovative diaphragm design and integrated solenoid valves. This ensures the stability of the air pressure and compliance with the required hygiene standards.
Conceptual design of a clean room
Barriers are required to monitor and control the movement of particles in cleanrooms. In the area of passages for people and material, these are realized via defined pressure zones.
The pressure zones are realized with the smallest pressure differences <25 Pa (corresponds to 0.00025 bar). This difference is already sufficient for effective protection. This ensures that air movement and thus the exchange of particles is avoided. The path of the particles can therefore be controlled. High-precision differential pressure measurement technology also increases energy efficiency.
In the classic cascade airlock, the differential pressure drops starting at the product. This creates a particle movement away from the product. The product is effectively protected.
The bubble airlock uses a ‘bubble’ of clean air to separate the cleanroom from less clean air. This airlock is realised by an increased differential pressure to the cleanroom and the corridor.
The sink airlock has a lower pressure inside the airlock and a higher pressure on the other two sides of the airlock. Here, air is drawn in from both neighbouring areas, creating a low-pressure barrier and preventing the possibility of impurities entering the inner area.
A double chamber airlock consists of two separate chambers that serve as an intermediate space between a clean room and a less clean area. Each chamber is individually controlled in terms of cleanliness and pressure.
Room-in-room concepts offer efficient and flexible solutions in cleanrooms by creating isolated areas within a larger cleanroom. These concepts make it possible to adapt to different production requirements at minimum cost. The air consumption of the individual zones is independent of each other. The effects on the pressure zones due to varying air consumption must be taken into account.
Continuous measurement of the pressure conditions using a monitoring system offers a tried and tested solution here.
Controlled positive and negative pressure in the clean room
Automatic zeroing in differential pressure transmitters ensures reliable pressure measurements by regularly adjusting the zero point of the transmitter. This is done by an integrated zeroing valve. This automatically performs zeroing to prevent drift or shifts in the zero point. This ensures stable measurement results even over longer periods of time.
This valve also protects the transmitter against overpressure. When critical pressure limits are reached, it opens automatically to equalise the pressure and thus prevent damage to the transmitter.
This fully automated function ensures permanent and fault-free availability of the system.
Important terms in the field of cleanroom safety
Ensuring standards
ISO 14644
ISO 14644-1: Determination and classification of air cleanliness in cleanrooms based on particle concentration. This standard defines the cleanroom classes, e.g. ISO 5, ISO 6, etc.
ISO 14644-2: Requirements and monitoring methods for particle concentration in cleanrooms. Also covers monitoring and maintenance of cleanroom conditions.
ISO 14644-3: Test methods for verification of cleanroom performance, including tests for tightness, filter performance and airflow.
ISO 14644-4: Requirements for the design, construction and commissioning of cleanrooms.
ISO 14644-5: Operation of cleanrooms, including codes of practice, cleaning and maintenance.
ISO 14644-7: Requirements for cleanroom equipment such as laminar flow units, isolators and cleanroom cabins.
GMP (Good Manufacturing Practice)
EU GMP Guideline (Annex 1): Specific requirements for cleanrooms in pharmaceutical production, in particular with regard to sterility, production processes and quality control.
FDA cGMP (21 CFR Part 211): American regulations for the manufacture, processing, packaging and storage of pharmaceutical products, which also relate to cleanroom conditions.
ISO 50001 Energy management
The ISO 50001 standard deals with the topic of energy management systems and helps companies to systematically improve their energy efficiency. In this context, determining the air consumption of systems and cleanrooms is an important aspect of recognising and implementing energy-saving potential.
Controlling the air flow plays an essential role in cleanrooms and systems. Air consumption refers to the amount of air that flows through the cleanroom system in order to maintain the required cleanroom conditions.
In order to control air consumption precisely and continuously, the use of our P 34 with equipped P/T compensation has proven its worth.
Areas
Monitored areas
These areas are continuously monitored to ensure that they comply with the specified cleanliness classes. Measured variables such as particle concentration, temperature, humidity and differential pressure are monitored.
Examples: Production lines in the semiconductor industry, filling systems in the pharmaceutical industry, operating theatres
Areas subject to authorisation
Areas in which certain processes or changes must be approved in order to ensure cleanroom classification and product quality. These areas must be approved by the relevant authorities or testing institutions before commissioning or in the event of significant changes.
Examples: Pharmaceutical production facilities, cleanrooms for the manufacture of medical products
Advances in technology
Improved filter technologies
Advances in filter technology, such as HEPA and ULPA filters, enable even finer filtration of particles and microorganisms, resulting in a higher cleanroom class and lower particle concentration.
Modular cleanroom systems
Modular systems allow cleanrooms to be flexibly adapted to changing requirements. These systems can be set up and dismantled quickly and allow cleanroom areas to be easily extended or remodelled.
Flow optimisation and CFD simulations
Computational fluid dynamics (CFD) simulations are used to optimise the air flow in cleanrooms. This ensures more efficient particle removal and better control of air quality.
Energy efficiency
Modern cleanrooms are designed to minimise energy consumption, e.g. through the use of energy-efficient fans, optimised airflow systems and intelligent control technologies that adapt operation to actual requirements.
Solutions for clean and hygiene rooms
Standard transmitter
for basic applications
With our economical PS 17 and PS 27 series differential pressure sensors, the condition and degree of contamination of filter systems, for example, can be monitored in real time by monitoring the pressure drop. This allows the filter to be changed at the right time, saving resources, avoiding downtime and ensuring production quality.
Advantages
- Compact transducer with linear characteristic curves and optional display
- Measuring accuracy between 1 % and 3 % FS depending on version
- Individual, also asymmetrical measuring ranges up to ± 50 Pa
High-end transmitter
for demanding applications
The precise differential pressure transmitters in the P 26 and P 34 series meet the highest demands for measuring accuracy and stability, even in small pressure ranges. This means that pressure cascades in clean rooms or clean production zones, for example, can be continuously monitored - for consistently high production quality and reliable personal protection. Thanks to the inductive measuring principle, excellent long-term stability and optimum temperature behavior are guaranteed. The slightest pressure deviations are detected immediately. In combination with differential pressure transducers, the pressure transmitters can also be used for volume flow measurement.
Advantages
- High-precision transducers for the smallest measuring ranges of ± 10 Pa
- Measuring accuracy of 0.2 % or 0.5 % FS depending on version
- High overload safety due to integrated valve
- Integrated cyclical zero point correction for maximum long-term stability
- Extensive modular system of variants
Solutions for mobile pressure measurement
The compact KAL 100 / 200 calibration device and the EMA 200 hand-held device can be used as on-site test equipment to check or calibrate differential pressure transmitters in use quickly and easily. The portable, battery-powered EMA 200 digital pressure gauges measure positive and negative differential pressure and are ideal for customer service and maintenance work, e.g. on heating, ventilation and air conditioning systems or for filter monitoring, thanks to their ease of use. The KAL 100 / 200 calibration device is a combination of pressure transmitter and pressure measuring device. It can be used to test and calibrate pressure sensors and other pressure measuring devices for low pressures in a simple mobile manner - connection to an external compressed air generator is not required.
Advantages
- High accuracy and long-term stability thanks to automatic zero point adjustment, measuring accuracy up to 0.1 % FS depending on version
- Simple menu navigation for switching units, setting calibration points and defining the measuring span (in several languages)
- Generation of positive and negative differential pressures
- Convenient operation and creation of calibration curves via USB interface and PC
