Moisture in Oil,SMART-WIO



Moisture in Oil

Moisture and water activity measurement of lubricants, hydraulic oil etc.


The water-in-oil sensoring technology is a reliable system for measuring the water content in oil. Moisture is the second-largest source of pollution in the oil lubrication system after small particles, and it also greatly affects the life-span of the oil as well as mechanical products. Moisture can cause mechanical damage to the engines, cylinders, bearings, etc. and at the same time increasing maintenance costs and resulting in expensive downtime (typically EUR 10,000 - 200,000)

The degree of water solubility in oil varies greatly depending on the oil type, additives, degree of oxidation, temperature, and other factors. Therefore, the sensor needs to be fully calibrated to ensure the correct measurement of water content.  MZD Sensors offer the highest quality and highest accuracy in the industry, using sophisticated oil calibration and measurement methods.

The traditional method needs to sample and analyze the oil. The sensor provides continuous monitoring of the entire oil lubrication system, and at the same time alarms the high moisture content that may cause damage. In addition to providing alarms, it can also be used to ensure that separators, filters, and dryers operate on demand. The sensor transmits the signal to any external monitoring system, sends out alarm signals, and can provide on-site display at the same time.


Direct measurement of water activity, accurate and reliable monitoring of oil saturation point of the real margin of water. Chemical or laboratory methods are often used to measure the water content of the oil, either in percentage (%) or ppm.

Disadvantages of the laboratory method:

◆ The sample size is too small to be representative

◆ Poor timeliness - Loss has occurred before the results are available

◆ Usually only every one to two months

◆ The results of many different oil analysis methods are very inaccurate - for example, less than 1000 ppm. In many oil applications, the damage effect has occurred at 100 ppm.

◆ The moisture content of the oil system can be measured 24/7 by installing a MZD water-in-oil analyzer to eliminate these effects.

◆ Can be calibrated according to different oil products.

◆ Ability to provide early warning and avoid high maintenance costs and downtime.

Type of oil

◆ Lubricants   ◆ Gearbox oil  ◆ Turbine oil  ◆ Diesel fuel  ◆ Hydraulic oil   ◆ Transformers

Typical application

◆ Engine or oil systems –for two-stroke vessel engines up to high speed engines

◆ Gear boxes – repairing or/and reinstalling gear boxes in machines, turbines or vessels is very expensive

◆ Turbines - e.g. gas turbines in powerplants, hydropower or wind energy

◆ Hydraulic systems – especially high pressure hydraulic systems are intolerant of water

◆ Transformers – water in the transformer oil can be very dangerous and critical to its safety

◆ Cooling/ventilation systems – keeping the cooling or vantilation systems up and running is critical

◆ Cylinders – adjacent machinery injecting the oil directly into the cylinders

◆ Pumps – especially large scale water or heat pumps

◆ Compressors – large industrial air compressors, for example in factories or power plants


◆ Ships  ◆ Electricity  ◆ Processing  ◆ Offshore platforms  ◆ Renewable Energy  ◆ Steel

◆ Food  ◆ Papermaking  ◆ Mining  ◆ Agriculture  ◆ Robots  ◆ Others

Product Features

◆ All-weather continuous measurement

◆ Highest measurement accuracy

◆ Stable performance

◆ GL certification

◆ MAN Diesel certification

◆ Calibration certificate

◆ Analog output

◆ Thread or ball valve mounting

◆ Electrical isolation

◆ High-quality cable

◆ Alarm point settings

◆ Easy installation

Technical Parameters

◆ Water activity (aw)

The sensor is easy to install and connect. Measurement range of 0.01-1.00aw, accuracy ± 0.03aw, resolution> 0.004aw. The default alarm values are 0.5aw and 0.9aw (changeable on the controller). Under the condition of installation with a ball valve, the maximum working pressure of the sensor in oil is 10 bar. For threaded installation, the maximum pressure is 20bar, with the working temperature between 0℃ and 90℃.

◆ ppm

The typical measurement range is 10~20,000 ppm (the upper limit is only due to oil saturation), the maximum pressure is 300bar, and the working temperature is −20℃ to +70℃.


◆ Easy to install, directly on the tank or pipeline.

◆ The installation location requires a certain flow rate.

◆ The sensor should be installed where the water content in the oil can best reflect the problem. E.g:

◆ The leakage of the cooler due to incorrect operation, the measurement point should be selected behind the pipeline close to the output of the cooler.

◆ If you want to monitor the new oil added to the system, the measurement point should be selected on the siphon line of the pump.

◆ When the sensor is installed on the pipeline, the sensor must always be immersed in the oil. The location of the sensor must not have precipitation.


◆ 24/7 monitoring and early warnings

◆ Increase the lifetime of engine parts, cylinders, bearings, etc.

◆ Saved damages and downtime costs

◆ Longer oil lifetime

◆ Saved oil sample costs (and administration)

◆ Potential savings on water filters, separators, etc. (only running when needed)

◆ Avoided commercial costs and negative customer impact (from downtime and delays)

◆ Higher accuracy than most oil sample tests and real time answers

◆ Higher accuracy and real-time measurement than most sampling tests

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