Non-contacting speed measurements

Modern paper machine configurations frequently have, despite increases in speed, a smaller number of drives in permanent operation than was the case in earlier years. This means that with modern paper machine constructions the drive energy is transmitted to many positions predominantly through the sheet and via elastic bands (clothing) and roll covers. As the transfer of the paper sheet from one part of the machine to the next nowadays generally occurs without open draw it is essential that the same speeds or at most minimal draws should be established and maintained. All rolls, cylinders etc. will vary in their diameter to an unknown extent as a result of temperature influences, to which must be added the differing thickness of the clothing used. These facts complicate the matching of the number of revolutions of rolls and cylinders to the required circumferential speeds. These factors are amongst the reasons why non-contacting speed measurement is becoming evermore necessary. The currently possible recording of data and manual adjustment of the required speeds can only be a temporary solution. Therefore a fixed installation of sensors to record speed combined with automatic speed adjustment will in future be indispensable. Introduced here is a method of non-contacting speed measurement which can record and document clearly the measuring values needed for such a task. Specifically for this Heimbach in co-operation with Corrsys have developed a new measuring unit operating on a light basis. The examples given of practical measurements intentionally do not go into the solution of specific problems but are designed to indicate the variety of measuring possibilities and the results obtained.