Industrial wear sensor for compressors – RSens

taking the guesswork out of maintenance planning

2M Engineering developed, certified and produces an industrial wear sensor to measure wear inside gas or oil compressors. The so-called RSens is commercialized by Howden Thomassen Compression Systems.

Rsens™ is a radically new concept that allows you to measure the condition of the rider rings with a high degree of accuracy. At the heart of the system is a sensor located inside the cylinder head end-cover, which has a direct view of the position of the piston within the cylinder and can thus provide a definitive reading of the distance between the bottom of the piston and the cylinder liner. This is the critical factor in planning rider ring replacement, and Rsens™ provides a constant value to within 0.1mm. A new reading is taken at every stroke so that you have a precise measure, in real time, of the exact thickness of the bottom section of the rider ring, the area where the wear is most severe.

Industrial compressor sensor

Accurate measurements from within the compressor

Today’s problem if you want to do preventative maintenance is the need to manually open the compressor to check for wear and service requirements. Furthermore it is impossible to perform real-time measurements inside the compressor when operational. The solution 2M created together with our partner is an Eddy current sensor that can withstand the extreme conditions inside a compressor, while measuring in real time to within an accuracy of 50 microns.

Precision measurement in harsh environments

Besides usage in the petrochemical industry it can also be used in other industrial application where distance measurements needs to take place under extreme conditions.

The Problem

Planning can only be as precise as the data it is based on. One of the fundamental problems associated with reciprocating compressors designed for continuous running is the timing of maintenance breaks. Proper intervention, at the right time, is the key to long-term economy and efficiency. By leaving essential maintenance too late, you run the risk of catastrophic, and very expensive, failure and lost production. Carrying out maintenance too frequently, however, also incurs unnecessary cost. Expensive parts are replaced earlier than they have to be, and valuable production will be lost in the additional downtime. One of the most regular, and most essential, maintenance tasks is the replacement of the piston rider rings, so accurate information describing their condition is invaluable. If you replace them too early, viable rider rings are needlessly scrapped. If you leave it too late, there will be consequential damage to the cylinder liner, necessitating an even more costly operation. An accurate method of measuring wear is the only way to achieve reliable, cost effective maintenance by getting the timing exactly right. For the first time, such a system is now available. The Howden Thomassen Rsens™ is an investment that will repay its capital outlay in both cash and peace of mind.

Key features

  • Provides accurate and reliable wear measurements inside gas or oil compressors
  • Works under extreme temperature and pressure conditions in harsh environments with aggressive gases and fluids
  • Reduces maintenance and service costs, increases safety and machine uptime
  • Patented technology
  • ATEX certified: explosion zone 0, T1-T4



  • Design pressure: 250 bar
  • Test pressure: 350 bar
  • Measuring range: 0.3 – 3.0 mm
  • Maximum operating temperature: 150˚C
  • Minimum operating temperature: -60˚C
  • Classification Ex II 1G Ex ia IIC T4

Signal processing unit

  • Maximum ambient temperature: 60˚C
  • Minimum ambient temperature: -40˚C
  • Classification CE (ATEX)
  • Output signal 4–20 mA
  • Supply voltage typical 24V DC
  • Explosion zone 0 and 1
  • Shock Rating 100g single hit (IEC standard 68-2-27 – survivability)
  • Vibration Rating 5g/10-150 Hz (IEC
    standard 68-2-6)
R-Sens Industrial Wear Sensor

More information

RSens Brochure (pdf)