THE RIGHT MODEL FOR EVERY APPLICATION.
Scroll down
Accurate and reliable measurements are a prerequisite for any high-quality industrial production. Measuring instruments are used, among other things, for the quantitative determination of properties as well as for control, regulation, and automation in production, and are an important component of industrial quality assurance. One relevant process and production variable whose accurate and reliable measurement can be crucial is pressure.
For example, in the production of food, pharmaceuticals, plastic parts, and many other industrial sectors, the correct pressure is crucial for product quality and the efficiency and safety of the production process. If plastic bottles, for example, are inflated to the wrong pressure during production, they will not last. Steam boilers can explode if safety valves are not working properly. Correct and permanently reliable pressure measurement is only possible with regular calibration. This is because pressure gauges, pressure sensors, pressure switches, safety valves, and generally pressure equipment of all kinds are subject to stresses during their service life, such as changing ambient conditions or aggressive media. Therefore, an (imperceptible) loss of measurement accuracy, known as drift, is almost inevitable over time. This is where pressure calibration comes into play.
Especially in pressure-sensitive production processes – where pressure is a process-critical variable – regular pressure calibration is mandatory, among other things, to avoid disruptions in the process flow or safety risks.
What is pressure calibration?
Pressure calibration ensures that the deviation of the displayed value of the pressure measuring device (e.g.: pressure gauge, pressure sensor, etc.) is known and can be taken into account for a correct measurement. For this purpose, the pressure measuring device to be calibrated and a calibrated reference pressure gauge, which represents the true value, are exposed to the same pressure within a self-contained pressure system. The measured values are then compared and the deviations documented in a certificate. The deviations determined by pressure calibration can later be used to adjust the pressure measuring device. Please note, however, that the calibration certificate is then no longer valid because a change has been made. In this case, recalibration is necessary for a valid certificate.
Which devices can and must be pressure calibrated?
In principle, every pressure measuring device is subject to drift over time, which may result in the specified and required measurement accuracy not being met. Calibration determines the deviation and can be incorporated into the measurement accuracy assessment. Pressure measuring devices must be calibrated if the pressure they measure is a process-critical quantity.
Advantages of pressure calibration
In addition to the production-related requirements that necessitate pressure calibration, calibrated pressure gauges and pressure sensors offer further advantages: Reliable measurements and correct production pressures contribute to higher productivity, reduce the risk of unexpected production downtimes, are a basis for meeting environmental regulations, and contribute to profit optimization through more efficient production.
Good reasons for pressure calibration
- High and consistent product quality
- Compliance with industrial standards and legal regulations
- Process optimization and increased productivity
- Avoiding unexpected production downtimes
- Profit optimization
How often do I need to calibrate my measuring instruments?
Calibration frequency is a trade-off between risk and cost. The shorter the time between calibrations, the lower the risk of inaccurate measurements. Calibrating measuring instruments once a year is often recommended.
How to calibrate pressure gauges and pressure sensors?
The practical implementation of a pressure calibration requires only a few steps and is completed in a few minutes. The pressure gauge to be calibrated or the corresponding pressure sensor – the so-called test piece – is connected either directly or via a hose to the pressure calibrator. This essentially consists of a reference pressure gauge and a pump for pressure build-up. For calibration, the test piece and the reference pressure gauge are subjected to the same pressure and compared. The difference between the two readings is documented in a certificate. This completes the calibration. A subsequent adjustment of the test piece is possible, but the created calibration certificate will then become invalid..
Similarities and differences in calibrating pressures
Difference between pneumatic and hydraulic calibrators
Pressure calibrators are generally divided into pneumatic and hydraulic versions based on the pressure build-up principle used. Pneumatic pressure calibrators use ambient air as the calibration medium, while hydraulic ones operate with oil or — as is possible with some SIKA pressure calibrators — with tap water. A force is required to generate pressure in the pump body. With hand, lever, or spindle pumps, this is done manually by the user.
Similarities of calibration procedures
All calibration procedures use a reference measuring device (REF) or a dimensional standard in addition to the device under test (DUT) to determine the display deviation of the device under test. Following the calibration procedure, an adjustment can be performed. The goal of this adjustment is always to eliminate the determined deviation or at least reduce it to such an extent that the remaining measurement inaccuracy lies within a defined tolerance range.
Differences between calibration procedures
In addition to the calibration medium and the associated pressure and application range, calibration methods can be divided into direct and indirect comparative methods. While direct comparative calibration methods use a reference measuring device and read the applied pressure from it, indirect comparative methods use a measuring standard. Oil deadweight testers operate according to this principle. The reference pressure is determined using weights and the the gravitational force.
Differences and areas of application of pneumatic and hydraulic pressure calibration methods
Pneumatic and hydraulic calibrators not only use different calibration media, they also each have their own specific purpose. Since pneumatic calibrators can create a vacuum, they can also be used for calibration in the negative pressure range. The application range of hydraulic systems, on the other hand, begins at 0 bar relative and extends up to over 1,000 bar, far beyond the application range of pneumatic systems. This is due to the calibration medium. Hydraulic oil allows for the build-up of high pressures much more easily than is the case with ambient air. Another factor in selecting the right pressure calibrator is the application area of the test object to be calibrated. For example, pressure gauges and pressure sensors in the food or pharmaceutical industries often must not be wetted or come into contact with hydraulic, aggressive, or ionizing substances. Pneumatic or hydraulic pressure calibrators that can be operated with water are ideal for this. For pressures above 1,000 bar, systems that operate with hydraulic oil are recommended, as its higher viscosity allows for easier test pressure generation.
SIKA Quality standards in calibration technology
We have had a DAkkS-accredited pressure laboratory since 1995 and have been a member of the German Calibration Service (DKD) and accredited according to DIN EN ISO/IEC 17025 since the same year. For over 20 years, we have been actively contributing our experience to working groups and regularly participate in interlaboratory comparisons.
Our pressure calibrators are developed and designed according to DAkkS (German Accreditation Body) requirements and guarantee long-term reliability and the highest quality. They therefore support our customers in ensuring consistent product and production quality. Upon request, our pressure calibrators are available with a calibration certificate bearing the DAkkS accreditation symbol. As an official certificate, this unconditionally proves traceability to national and international standards and is internationally recognized.
When is a DAkkS calibration certificate recommended?
The DAkkS is responsible for the accreditation, monitoring and assessment of laboratories according to DIN EN ISO/IEC 17025. The delivery of a pressure calibrator with a DAkkS calibration certificate is recommended for:
- very high quality calibrations
- required international recognition
- requirement for complete traceability of calibration
- the calibration of test equipment, which in turn is used as standards for testing other test equipment
- for compliance of internal company requirements
Pressure calibrators from SIKA Dr. Siebert & Kühn
Development history of pressure calibration at SIKA
We have been developing and manufacturing pressure calibrators for 20 years and specialize in hand-operated, portable systems for on-site calibration and testing of pressure equipment. Today, we offer a complete range of pressure calibrators for a wide variety of applications up to 1,000 bar, as well as customized versions even in small quantities.
First/outstanding products
Until the early 2000s, pneumatic pumps existed exclusively with a maximum operating pressure of 20 bar. In 2010, SIKA developed the P40, the first hand test pump designed for pressures up to 40 bar. This was later followed by the P60, a model with an operating pressure of up to 60 bar.
Accuracy information
A pressure calibrator consists of a pressure generator (hand pump, spindle pump, or lever pump) with the corresponding reference pressure gauge. SIKA offers products across twelve pressure levels, ranging from -1 to 1,000 bar, with accuracies ranging from 0.5% to 0.05%.
General areas of application
Our hand test pumps and table top test pumps enable the testing, adjustment, and calibration of pressure sensors, pressure gauges, pressure switches, safety valves, and pressure devices of all kinds. Our pressure calibrators are optimized in function and handling and can be connected to all common pressure systems. We also offer specific adapters for customized solutions.
Overview of SIKA pressure calibrators
Our product range includes both pneumatic and hydraulic pressure calibration devices.
Pneumatic calibrators
Air is the ideal test medium, especially in applications in which the device under test must cannot be wetted or where aggressive or ionizing substances cannot be used. SIKA's pneumatic test pumps meet requirements that other suppliers can often only cover with multiple products. The P4, P40, and P60 allow direct switching between pressure and vacuum, pressure generation up to 60 bar, fine adjustment in the mbar range, and stable pressure conditions with drop rates of just a few mbar per minute.
Hydraulic calibrators
We developed our easy-to-use hydraulic test pumps specifically for medium to high-pressure applications. Thanks to the built-in hydraulic fluid reservoir, they are also highly mobile and, with measuring pressures of up to 1,400 bar, extremely flexible in their use. Our test pumps and pressure calibrators enable the testing, adjustment, and calibration of pressure sensors, pressure gauges, pressure switches, safety valves, and all types of pressure equipment.
Oil deadweight testers
The principle of this calibration system is based on the balance between forces acting simultaneously on a piston from above and below. Calibrated weights (the measuring scale) generate a mechanical force from above, while pressure is applied from below via hydraulic oil. When both forces are balanced, the piston begins to float in the cylinder, and the desired test pressure within the system is reached. The actual pressure displayed on the test piece can now be read and compared with the target pressure in the system, determined by the set of masses applied.
Hand test pumps – mobile, adaptive and independent
Lightweight, compact and easy to transport
Our pneumatic hand test pumps are lightweight, fit in any toolbox, and are easy to transport.
Adaptation to every measurement situation
Connected via a robust, industrial pressure hose with a quick-release coupling, our hand pumps can be quickly and easily adapted to all common pressure systems. An ultra-fine thread pitch and a large-volume regulating valve enable precise adjustment in the mbar range, while tool-free switching allows for quick switching between overpressure and vacuum generation.
Independent of the electrical power and compressed air network
Thanks to their design and operation, our pneumatic hand test pumps require no additional power supply or connection to a compressed air network. Wear-free pressure generation is simple and smooth in manual operation, regardless of the ambient temperature.
Wide scope of application
Comprehensively and thoroughly designed for mobile use, our pneumatic hand test pumps up to 60 bar cover every production stage and process, from assembly and manufacturing to maintenance, quality assurance, and repair. Our pneumatic hand test pumps are available in three versions up to 4, 40, and 60 bar.
Ease of use
As the name suggests, the desired test pressure is generated manually using the handles on our pneumatic hand test pumps and then precisely adjusted using the fine-adjustment valve. This ensures the same pressure level is maintained on both the test specimen and the reference instrument. The pressure relief valve allows for continuous pressure reduction. This ensures precise and easy testing even when pressure drops. Analog and digital pressure gauges, as well as handheld measuring instruments, can be used as reference instruments.
Table top test pump with spindle wheel
Precise even at maximum pressure
Our latest generation of table top test pumps guarantee precise measurements and long service life, even at high pressures. All parts in contact with the media are made of stainless steel, ensuring wear-free operation.
Mode of operation
Our table top test pumps feature a large base plate. This ensures high mechanical stability and allows for easy installation of test specimens, even those with large nominal diameters. The built-in adapters on the pressure connections also allow the reference pressure gauge and test specimen to be freely aligned. This allows for virtually any test situation to be accommodated.
Test medium
Depending on the model, both distilled water and hydraulic oil can be used as the test medium.
Easy operation
Filling the pressure vessel and generating the test pressure is very easy using a rotating spindle. Thanks to the pressure fluid reservoir installed as standard on the test pump, even large volumes can be easily charged. Pressure fluctuations caused by air and gas components in the filling fluid, the compensation of thermodynamic effects, and the precise setting of the desired test pressure are all handled by the fine adjustment.
Table top test pumps with lever
Compact on the outside, large on the inside
Despite their compact design, our lightweight high-pressure hydraulic table top pumps feature a large tank with a usable volume of 327 cm3. Combined with a displacement of 0.9 cm3 per piston stroke, they offer the possibility of testing multiple test specimens in parallel.
Quick test setup
The test specimens are mounted either directly on the supplied pressure hose or via a separate distribution block. This saves time and makes your testing process extremely efficient. The integrated check valve in the pressure vessel ensures stable pressure conditions very quickly, and the built-in safety valve protects against overloads.
Oil deadweight testers
Our oil deadweight testers have a reading accuracy of 0.015% of the final value. They are supplied with a SIKA calibration certificate traceable to national and international standards, or alternatively with a DAkkS certificate. At no additional cost, the deadweight testers can be adjusted to the local gravity acceleration instead of the standard gravity acceleration of 9.80665 m/s².
Accessories, service and spare parts
Our calibration devices are available with a carrying case and adapter set. We also offer a wide range of other accessories and spare parts, such as seal kits, pressure hoses, inlet and outlet valves, fine adjustment and pressure relief valves, and plate weights for oil deadweight testers.
Reference pressure gauge - accuracy & characteristics
Our product range includes a wide variety of analog and digital pressure gauges, from Bourdon tube pressure gauges to precision digital pressure gauges in industrial versions, with various accuracy classes ranging from 0.5% to 0.05%. Both analog and digital pressure gauges have distinctive properties. Digital versions measure pressure reliably in any position, whereas analog precision gauges must be held vertically for accurate measurements. Furthermore, digital pressure gauges are less sensitive to vibration and offer greater reading accuracy and display resolution. Analog pressure gauges, on the other hand, require no power supply and no temperature compensation or acclimatization. All of our digital reference pressure gauges can display pressure in the units bar, mbar, kPa, MPa, PSI, and kg/cm².
Calibration service
Our calibration laboratory for absolute pressure and positive gauge pressure offers a full range of calibration options for indicating analog and digital pressure gauges, as well as pressure sensors with electrical output signals such as 0-10 V or 4-20 mA. Calibration is performed as a comparison measurement against a piston gauge used as a reference standard. Using the piston gauge, the calibration item can be subjected to defined pressures in the range of 1-1,200 bar. The smallest possible measurement uncertainty is 0.7 mbar, depending on the measuring range. A DAkkS calibration certificate is available upon request.
Sales
Have we sparked your interest? Our sales specialists will be happy to provide you with personalized advice, including on spare parts and accessories.
Service and After Sales
Our Returns Management team handles all repair and calibration orders, as well as complaints. For returns, however, your sales contact is the first point of contact. Please use our RMA form in all cases. This allows us to process your request as quickly as possible and keep you informed of the order status.