PM 41 / PMI 41
IR sensor for measuring quartz tube temperatures of uv lamps
The infrared sensor PM41 measures IR radiation at 4,5 to 4,8µm. As quartz by physical reasons blocks the short wave IR radiation of the arc lower than 4,5µm, the sensor only measures the long wave IR of the quartz tube itself. As a result it measures the real temperature of the tube, nothing else.
Up to now it was very difficult to measure the real quartz tube temperature of UV lamps while operating. Normally it is done with thermo elements or resistance wires. Principal disadvantage of those sensors is the additional heating of the sensor by the IR radiation of the arc itself and an additional cooling of the sensor by the normally necessary cooling air flow for the lamp.
The sensor takes a bearing on the lamp with a distance of approx. 40
to 100 mm, while the spot size on the lamp tube is 3.8 to 13 mm of diameter. It is important to have an aperture between lamp and sensor to protect the sensor housing to the lamp heat. Max. housing temperature is 65°C.
The measuring spot on the lamp tube have to be smaller than the tube diameter, otherwise a mixed temperature of lamp tube and background will be displayed. The hole diameter has to be adopted to its placement within the measuring area, shown in the picture below. As an example it could be mounted on the rear side of a lamp head and takes its bearing through-out a hole in the lamp housing.
By an optional air flush ring (for pressurised, clean air) in front of the sensor opening a pollution by e.g. dust could be avoided or reduced.
The IR sensor is available in two different versions:
- IR-Sensor with cable connection (PM 41; Art. 150) or
- IR sensor with intelligent plug (PMI 41, Art. A004503) to use in combination with the handheld HI to display the temperature values