A precision dew point measurement with remote heads

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MBW 473

cable mounted measuring heads
climate chamber validation
Forcefrost^TM function

Flexible measurement options with the 473 chilled mirror.

The determination of dew point by monitoring condensation on a temperature controlled mirror allows a highly accurate (±0.1 °C) measurement. With a typical service life of more than 15 years, MBW chilled mirror hygrometers provide highly accurate and stable measurements over a long service life.

The 473 is a transfer reference standard instrument designed to validate a wide variety of climate chambers and moisture generator systems.

Optimum Response Injection System (ORIS)

In common with other models in the range, the MBW473 has the ORIS facility, reducing stabilisation time when measuring at low dew point levels. ORIS uses a pre-programed vapour injection procedure to accelerate the formation of a frost layer on the chilled mirror surface.

A graph showing the improvement in stabilisation time when using ORIS

Forcefrost^TM function

Below 0 °C water may condense as either liquid or solid. This is a particular problem when working at dew points just below 0 °C, and can cause up to a 3 °C difference in condensation temperature. For correct calculation of relative humidity (rh), the phase of the condensate must be known. When the Forcefrost function is activated at a user defined temperature the mirror over-cools to ensure that a frost is formed when below 0 °C, and to remove the uncertainty.

COMPATIBLE MEASURING HEADS
	RP2 Measuring Head To allow optimum placement in working volumes of air, the RP2 head includes a 2-stage thermoelectric cooler (Peltier) element in a compact probe. Range: -20 to +70 °C Order code: 103692
	SH2 Measuring Head Ideal for climate chamber validation, humidity generators, engine test cells and on-site calibration projects, this flow-through head assembly includes a variable speed fan that pulls a consistent airflow across the mirror. With the fan removed, the SH2 can be connected to applications using tubing and a standard 6 mm or 1/4 " fitting. Range: -30 to +70 °C Order code: 103693
	Precision Temperature Measurement Both the RP2 and the SH2 versions of the 473 are supplied with a 4-wire PT1000 Platinum Resistance thermometer (PRT). The temperature probe can be directly connected to the measuring head, or by cable to the 473 back panel, allowing precise temperature measurements to be made for the calculation of rh. Range: Head Mounted: -20 to +80 °C Cable mounted: -50 to 100 °C RP2: Ø3 x 30 mm PRT, 0.5 m cable SH2:Ø2 x 100 mm PRT, 0.5 and 3 m cables
	Transit Case Each 473 is supplied with a robust IP65 transit case for safe transportation to site for calibration projects.

Order Code	Description
103693	Model 473, with SH2 Head assembly on 2 m cable, range -30 to +70°C dew point, 100x 2mm PRT temperature probe with 0.5 and 3m cable. Complete with transport case
103692	Model 473, with RP2 Head assembly on 2 m cable, range -20 to +70°C dew point, 30 x 3mm PRT temperature probe with 0.5 cable. Complete with transport case
Options
103846	473 upgrade factory calibration to ISO17025
102662	Analogue outputs, user programmable, 2 x 4to 20mA or 0 to 10V
100282	0.1% accuracy internal barometric pressure sensor
103954	0.01% accuracy internal barometric pressure sensor
103632	Additional 1 year warranty upgrade (maximum 3 years)
For a complete range of options and accessories, please contact us

	RP2	SH2
GENERAL
Measuring range
Frost/Dew point	-20 to +70 °C	-30 to +70 °C
Relative humidity	+5 to +100 %rh	+2 to +100 %rh
Temperature (head mount PRT)	-20 to +80 °C	-20 to +80 °C
Temperature (cable mount PRT)	-50 to +100 °C	-50 to +100 °C
Accuracy
Frost/Dew point	≤ ± 0.1 °C (-20 to +70 °C), ± 0.2 °C
Temperature	≤ ± 0.1 °C
Reproducability
Frost/Dew Point	≤ ± 0.05 °C
Temperature	≤ ± 0.05 °C
Standard Features
Temperature probe	Ø3 x 30 mm PRT, 0.5 m cable	Ø2 x 100 mm PRT, 0.5 and 3 m cables
Digital I/O	RS-232
Display	5.7" LCD with colour touch screen
Thermoelectric mirror cooling	2-stage with typically 50 °C depression at 20 °C ambient
Mirror temperature sensors	Platinum resistance thermometer (Pt100)
Gas connections	6 mm or 1/4 " Swagelok (SH2 only)
Transport case	Custom fit foam lined Peli 1550
Power cable	2.5 m
Operating instructions	English
Calibration certificate	Factory calibration: 5 points FP/DP, 3 points temperature. Upgrade to SCS accredited ISO17025 calibration available
Optional Features
Internal barometric pressure sensor	0.1 % or 0.01 % accuracy, 700 to 1200 mbar
Analogue outputs	User programmable, 2x 4 to 20 mA or 0 to 10 V
Additional Information
Instrument operating conditions	0 to 40 °C, 90 %rh non-condensing
Measuring head operating conditions	-20 to +80 °C, 99 %rh non-condensing
Storage conditions	-20 to +50 °C
MECHANICAL
	Instrument	In Transport Case
Dimensions	W310 x H155 x D265 mm	W510 x H220 x D450 mm
Weight	5 kg	12 kg
Protection	IP54	IP65
ELECTRICAL
Power supply	100 to 120 VAC / 200 to 240 VAC, 50/60 Hz, 100 Watt (auto switching)
All specifications subject to change