Paper - “Harsh operating conditions”
Paper machines run at a number of different speeds through the paper making process. For most standard paper machines 100mV/g units will be suitable, but there are some machines that have rollers rotating at under 60RPM and here higher sensitivity, 500mV/g units will be a better option. Generally 4-20mA sensors do not have much use on paper machines as they are limited to a temperature range of 90° C and in-depth diagnostics using ‘AC’ sensors is required to properly evaluate variable speed rollers.
The paper machine environment is very harsh. Generally as per the “environment” discussion point in mining side exit sensors (HS-100S Series) are the best option, where there is limited head room. Where space is not an issue the top entry version can be used (HS-100 Series) and provide a more cost-effective solution.
A lack of consideration for the paper machine environment is where many go wrong with permanently mounting accelerometers. As anyone who has had experience in this field will know some areas of paper machines are very humid, wet, hot and dirty. For all but the wet end of the machine top (HS-1001005008) or side exit low profile (HS-100S1005008) sensors rated to 140 deg C along, with 2 Pin MS connectors should be used. The 2 Pin MS cable assembly to match this should be IP66 and have a “silicon” type cable that is rated to 150 deg C. (HS-AC030) For the wet end of the paper machine IP68 submersible, integral cable sensors should be used again with a “silicon” type cable that is rated to 150 deg C. (HS-1001000708). If sensors are being used for routine data collection they should be terminated in an IP66 rated enclosure (HS-SE Series).