Sensor
The cast aluminium MCT 360 is built to withstand adverse environmental conditions and will perform reliably under ambient temperatures of up to 50 °C, if the ambient temperature exceeds 50°C but remains below 65°C, an MCT 700 is to be recommended..this requires no additional cooling supplies and is spray proof.
 If information is required from different locations cross web, for example to check the correct functioning of individual dies, Process Sensors offers a low cost manual scanner which enables the gauge to be “parked” at any position cross web or an automated scanner with an optional Profile Display System, PVDS.
Accessories
Installations at high temperature locations may well require a vortex cooler and cooling panel. Product loss sensors are required for measurement on discontinuous product, e.g. egg cartons.
Gauge outputs, Operator Interface & Display
The MCT 360 is available with or without a local operator interface or display as all the processing is carried out within the sensor head and the measurement is output via 4-20mA, 0-10V, RS232, RS485 or any bus. Installation time and effort is minimised by dispensing with a local OI, but should samples be collected for cross checks an OI is useful… in this event, one could be simply plugged into the gauge at the sampling location.
The Measurement
Measurement of glossy or wet surfaces requires the gauge to be angled approximately 17° to the product to eliminate spectral interference (reflections) from top surface. A passive reflector, e.g. a glazed white tile or a Teflon Strip is required to maximize the detector signal in the event a gauge is viewing transparent or semi-transparent (scattering) material.
Moisture , coat weight, and product temperature can be measured using NIR. Please note that thickness measurements, other than those of a transparent monolayer film are not feasible.
Moisture is measured at various stages throughout the paper making and converting process, also in corrugated paper and egg cartons. Various coating materials applied to either a paper, textile or plastic film substrate can be measured at either the wet end ( immediately after the applicator) or at the dry end. The MCT 360 measures both moisture and coat weight. If a coat weight measurement is required this can be performed either at the wet end (immediately after it has been applied) or at the dry end, after it has gone through a dryer, over a chill roller or through a curing process. The choice of dry or wet end measurement is dependent upon several factors:
- Whether the dry coating material absorbs in the NIR or not
- Best location for process control
- Simplest Installation location
- Measurement location that provides the lowest measurement error. Note that NIR is generally more sensitive to changes in moisture than organic (C-H) content, hence, even if the solids ratio is higher than 50%, a wet end aqueous measurement may still be the best choice.
Product temperature can be measured at any stage of a process.
Gauges are delivered pre-calibrated using customer samples when possible. Wet end measurements cannot be reliably pre-calibrated so must be set up once installed. PSC offers on-site commissioning and/or training.
Paper and Converting Applications
- Coatings e.g. clay, PVDC, hot melt and PSA adhesives on paper and film.
- Moisture in decorative laminates
- Moisture at various stages of the paper making process
- Moisture in paper products – after the remoisturiser
- Moisture in corrugated board
- Lacquer coat weight on aluminium sheet
- Moisture in sludge
|
