Calibration systems for vacuum gauges by Pfeiffer Vacuum

In view of increasingly stringent quality assurance requirements where the accuracy and reproducibility of the vacuum measured during production and service work is essential, as well as the vacuum gauges required for this, the demand for calibration systems is steadily increasing in the market place. In critical processes, the accuracy of vacuum measurements is important for process stability, quality and for monitoring these processes.

The pharmaceutical industry requires precise vacuum measurements for safeguarding its high-quality products, which is particularly the case when freeze drying expensive drugs. For this reason, regular calibration of vacuum gauges is required. This also applies for final vacuum measurements on vacuum systems in service applications in line with factory or international standards.

To cover the majority of applications, Pfeiffer Vacuum has developed two calibration systems – Basic and Pro system.

Calibration system Basic

• For static and dynamic calibration

• Calibration range 1.013 – 10 -4 hPa

• Easy to use

• Chamber ISO/TS 3567-compliant

• Up to three reference gauges for medium accuracy

• DAkkS-certified reference gauges

• Flexible

• We also deliver customised solutions

Calibration system Pro

• For static and dynamic calibration

• Calibration range 1.013 – 10 -4 hPa

• Easy to use

• Chamber ISO/TS 3567-compliant

• Up to five reference gauges for high accuracy

• DAkkS-certified reference gauges

• Flexible

• We also deliver customised solutions

Applications

• Freeze-drying in the pharmaceutical and food industry.

• Coating systems for optics, ophthalmics, decorative coatings, diffusion barrier layers for PET bottles and packaging films, wear protection coatings for tools, etc., incorporating the use of multiple measuring instruments.

• Final vacuum measurement in pump production and service workshops.

• Process monitoring and process control for determining the end of the process, in order to produce consistent quality and minimise rejection rates.

Calibration methods

Calibration is based on a comparison of the measurement values of the gauge to be calibrated and the reference gauge according to ISO/TS 3567. The gauge to be calibrated and the calibrated reference gauges are connected to a standardised vacuum chamber (according to ISO/TS 3567, form b) and are exposed to the same vacuum.

There are two basic methods of calibration – static and dynamic calibration. With the calibration systems supplied by Pfeiffer Vacuum, transmitters can be calibrated statically with a measuring range of >1hPa as well as dynamically with a measuring range of <1hPa.

Example of accuracy level of reference and calibrated gauges

Standard Unit

p (hPa) 1,003 · 10-4 2,001 · 10-4 4,004 · 10-4 7,003 · 10-4 1,001 · 10-3

under calibration

p (hPa) 1,004 · 10-4 2,002 · 10-4 4,006 · 10-4 7,005 · 10-4 1,005 · 10-3

The reference gauges values and the gauges to be calibrated must be determined for every defined pressure. According to ISO/TS 3567, at least three measuring points must be taken into account (e.g. 1, 2 and 7 in table).

The calibration results must be recorded in a calibration certificate in compliance with DKD 6-2 of the German Calibration Service (DKD) and be kept as proof of this. The user decides whether the deviations from the reference values are admissible. The deviations shown in the table are sufficiently accurate.

AIR & VACUUM TECHNOLOGIES

Mark Burn 0861 VACTEC (822 832) info@vactech.co.za www.vactech.co.za