MKS VACUUM GAUGE CALIBRATION GUIDE

INTRODUCTION

When working in an environment with pressure and vacuum, your MKS vacuum gauge provides you with stability and the tool you need to perform your work. However, that stability isn’t always there if you are not regularly or correctly calibrating the gauge. Especially if you are working in a regulated field, such as pharmaceutical, it is extremely important that you take the proper steps necessary to ensure your MKS vacuum gauge is properly calibrated.

In this whitepaper, we will take a look at the different types of vacuum gauges, what maintenance should be regularly performed on them, why they should be calibrated and how to find a calibration lab that fits your needs.


WHAT IS AN MKS VACUUM GAUGE

Capacitance manometers are a type of electro-mechanical gauge that are the ideal choice when measuring both pressure and vacuum. The MKS Baratron capacitance manometers measure true pressure and they are insensitive to the type of gas being measured. The Baratron capacitance manometers are known for being highly accurate and reliable, along with having an easy interface compared to other vacuum gauges. This is due to not only their performance, but their overall structure.

PARTS OF A CAPACITANCE MANOMETER AND HOW THEY WORK

When the pressure differences between the process and the reference cavity deflect the diaphragm, the distance changes between the diaphragm and the electrode. Variations in the distance cause variations in the capacitance between the diaphragm and the electrode. These variations are equivalent to pressure change. Because these differences are produced by physical changes within the gauge and not by changes in the properties of gas, pressure measurements are considered insensitive to the gas being measured.

TYPES OF CAPACITANCE MANOMETERS
BARATRON CAPACITANCE MANOMETER STRUCTURE

MKS manufactures the Baratron capacitance manometers with exclusive nickel-based alloys such as Inconel and Incoloy. These materials make the instruments resistant to corrosion. They are also constructed to assure overall operator safety. MKS’ manometer sensors are fully welded and are guaranteed to be 100% leak-check before assembly. This ensures that process gases are completely contained within the sensor in case of diaphragm failure. There are no other pressure or vacuum gauges that can ensure and offer this level of user safety.

OTHER TYPES OF VACUUM GAUGES
WHAT MAINTENANCE IS NEEDED FOR AN MKS VACUUM GAUGE?

Due to the structural design of the MKS capacitance manometers, little maintenance is needed to keep your instrument in tip-top shape. However, it is important to be aware of your surroundings when using a capacitance manometer to ensure accuracy and proper performance. In many cases, it is important to wipe the manometer down with a damp rag after use to keep it from particle buildup. Although capacitance manometers are relatively chemical resistant, users should be cautious when using halogen-based process and processes using oxidizing gases. Caution should also be used when using a manometer in the vicinity of electromagnetic forces. Most manometers are designed to have some degree of shielding to prevent interference, but if there is a high level of electromagnetic fields, the shield may not be enough. Because a capacitance manometer is an electronic device, any contact with a electromagnetic force could affect the equipment’s performance.

HOW TO KEEP YOUR MANOMETER ACCURATE
CALIBRATION

Capacitance manometers should undergo calibration on a regular basis. Because a manometer is an electromechanical device, calibration is required before installation, Manometers should also be periodically recalibrated to maintain accuracy and performance. If a user fails to recalibrate their manometer, there is a high risk of the performance window shifting. The consequences of a performance window shift could lead to reduced productivity, long periods of downtime or in extreme situations, complete shut down.

ZEROING

Zeroing occurs when the manometer output is adjusted to read zero. This can happen when the lowest pressure possible is achieved or when the there is a pressure lower than the resolution. Similar to calibration, zeroing has to be done before installation and periodically to ensure linearity. This is due to the impact gravity has on the position of the diaphragm.

It is important to note that every capacitance manometer is different. Because of the number of models available, it is vital for users to look over the manual to see what required maintenance is needed for that particular model, when zeroing should be performed and how frequently the instrument should be calibrated.

WHY SHOULD MKS VACUUM UNITS BE CALIBRATED

Calibration of a Baratron capacitance manometer and any other vacuum gauge is essential for ensuring the window of performance has not shifted. As previously mentioned, a shifted performance window could lead to reduced productivity, increased downtime and sometimes even complete shutdown of operations. These outcomes are never desired, therefore it is important to set a recalibration schedule and stick to it to ensure your vacuum gauge is performing efficiently. If your device is frequently calibrated you can be assured that your device is accurate, linear, repeatable and has the correct resolution and zero/zero offset.

These six benefits will make clear why you should regularly be calibrating your MKS vacuum gauge.

EQUIPMENT ERRORS ARE CORRECTED AND IDENTIFIED

This benefit is extremely important because if these issues are not corrected it could affect your service and processes, which in turn could lead to safety issues, unhappy customers and a decrease in revenue.

VERIFICATION OF APPLICATION COMPATIBILITY

This should be verified from the very start when first purchasing a vacuum gauge. If the application is not compatible with the device, gauge readings will not only be off but a plethora of issues could occur, which in turn could also lead to safety issues, unhappy customers and a decrease in revenue.

CORRECT GAUGE READINGS

When readings are correct, you can be sure that your equipment is working properly. This is the most important benefit of calibration.

UP-TO-DATE EQUIPMENT CERTIFICATION

By calibrating your equipment frequently and having an update to date certification, you are showing your customers you care. The certificate shows that the devices you are using are accurate and reliable.

DEPENDABLE INSTRUMENTS

Monitoring and testing procedures run smoother when using dependable instruments. By calibrating your gauges, you are ensuring yourself stability.

HIGH-QUALITY PRODUCTION

When a gauge is calibrated, downtime is minimized and research validity is ensured.

HOW TO CHOOSE A CALIBRATION LAB FOR YOUR MKS VACUUM GAUGE

Finding a calibration lab for your MKS vacuum gauge can be hard. Below are a 5 questions you should be asking yourself before choosing a provider to ensure you receive accurate and quality service.

QUALITY MANAGEMENT SYSTEM

Is the provider ISO/IEC 17025 accredited?

Accredited calibrations labs are rigorously assessed on factors relevant to the operation of the lab. During assessment, accrediting bodies observe the personnel, the equipment and the environment to ensure all meet ISO 17025 standard. This quality management system is considered the highest standard, therefore any lab that meets its requirements is deemed technical competent to the highest degree. If a lab you are considering is accredited and includes calibration of your MKS vacuum gauge in their scope of accreditation, this means the lab is fully equipped to give you accurate measurements on your instrument.

PERSONNEL

Are the technicians familiar with the measurements needed for your gauge?

Laboratory personnel should meet the qualifications you are looking for in order to properly calibrate your vacuum gauge. If a lab is accredited and includes your vacuum gauge in their scope of accreditation, this means the personnel have been assessed on this procedure and are knowledgeable in accurately calibrating your vacuum gauge. By choosing an accredited lab with personnel who specialize in the measurements you are seeking, you are guaranteeing yourself quality results.

ENVIRONMENT

Is the laboratory environment controlled?

Not all laboratories have a monitored and controlled environment. When choosing a laboratory it’s important to note that an environment that is monitored is desired. This is because certain environment conditions, such as temperature and humidity, can interfere with measurement results. Accredited calibration labs are required to consistently monitor their environment to ensure there are no adverse effects.

TRACEABILITY

Does the provider offer calibration certificates and data sheets?

Traceability is essential when it comes to calibrations. When a provider can show proof that an instrument is traceable through NIST, customers can feel confident in the service they are receiving. Accredited calibration labs are required to trace all instruments calibrated through NIST.

PRICING

How much will the service cost?

Costs for calibration can be very costly. Don’t let a price tag scare you. Quality over quantity is the best motto to follow when calibrating your MKS vacuum gauge. If you choose to go with a lab that has cheaper prices but isn’t accredited, you are not guaranteeing yourself accuracy. Notably, it will cost you more to pay for a cheap calibration that ends up failing compared to paying for an accredited calibration that will give you precise results.