DP30 - DEW POINT HYGROMETER WITH A CHILLED MIRROR 

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laboratory humidity model scope of dew point measurement between -95 °C... +95°C "ORIS" system - fast measurement stabilization many versions available heavy duty transport packing

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REMARKS: The Model DP30 is no longer available, replaced by model 373

Description

Model MBW DP30 is a precise dew point hygrometer, which meets highest requirements concerning measurement techniques of air, gas and gas mixtures of any type. Its wide scope of humidity measurement stays in the interval -95 °C... +95 °C of dew point temperatures. Additional possibility of gas measurement under pressure makes it possible for this device to be used in a wide scope of applications.
As all of the devices produced by MBW that measure dew point - in model DP30 a rule of chilled mirror with an optical detection was applied. It guarantees direct (definitional) and accurate measurement of current humidity without additional errors and hysteresis. The measurement system is stable and does not require recalibration. The condensation settled on the mirror is removed during an automatic check and a heating procedure what allows on keeping constant measurement accuracy.

Hygrometer MBW DP30 is available in many versions: can be equipped with one, two or three step Peltier’s heat pump and an airtight and heated measuring head (for measurements of high humidities). Internal gas circuit cable for measurement of corrosion aggressive gases is made out of stainless steel PTFE. Important and additional device option is provided by the ORIS system, which realizes a system of fast frost point temperature measurement stabilization for very low humidities (patent protected, described below).

A gas pump and an electronic flowmeter that work independently form the device's position are built in and provide standard device equipment. Two analog outputs and a digital output (RS-232) provide process control and measurement result reading. The device is easy to be transported and is provided in a casing to be placed on a table or in a casing to be assembled on stands “19" type: rack. Strong transport case provides device additional equipment.

ORIS

The ORIS method (Optical Response Injection System) allows on performing fast measurements at low frost point temperatures usually below -60°C. Typically, with such low temperatures a hygrometer’s mirror has to cool down to a value much below the actual frost temperature in order for the frost condensation on the mirror to start. Because of low water steam content in gas such process may last a long time before an adequate frost layer appears on the mirror and the measuring system stabilizes. Very often it can last even few hours. The lower the frost point temperature the longer the time of measurement stabilization.

This problem is solved by the ORIS method. It is performed through injection of small amounts of water steam to the measured stream of gas which starts frost condensation on the mirror what significantly diminishes the length of time necessary for obtaining the balance point for the measuring system. The measurements that lasted few hours or more can now be performed in few minutes using the ORIS method.

Typical applications

• industrial processes control,
• machines laboratory tests,
• climate chambers and rooms with controlled humidity,
• environment monitoring,
• electronic elements production,
• calibration of other humidity meters.

Technical data

PARAMETER	VALUE
Scope of dew point temperatures  measurement (values depend on gas pressure):	-60....+60°C DP (measuring head model SH)
	-60....+95°C DP (measuring head model BCS)
	-95....+20°C DP (measuring head model SHSX in a system K 1806)
Accuracy:	+/- 0,1°C
Repetitiveness:	+/- 0, 05°C
Reading:	Digital, 4 i 1/2 digits
Analog outputs:	10 mV / °C (0 °C = 0 mV) i 4...20 mA (free choice of measurement scope )
Digital output:	RS-232
Principle of measurement:	Dew point on a chilled mirror, rhodium coated, optical detection
Cooling:	Thermoelectric, Peltier element, from 1 to 3 steps
Additional cooling:	- Water with an automatic flow control, consumption of approximately 1 l/min. (standard equipment) - Additional cooling set K 1806 for measurements in the scope of temperatures lower than -60°C DP (optional)
Measuring head heating:	+40...+100°C for measurements in the scope above +20°C DP
Measured gas flow:	15 to 60 l/h, nominal 30 to 40 l/h
Flow measurement:	Built in electronic flowmeter, independent form thr device position
Examined gas pressure:	10 bar / 1 Mpa maximum
Response time:	2°C/sec maximum
Gas pump:	Built in (standard equipment)
Mirror control:	- Automatic (AMC), periodical with a set operation interval - Manual (MMC) in any moment
Automatic control set:	Used during automatic mirror check. Displays the last measured value and procedure repetition time.
Stand by status switch:	Allows on switching the device on without taking the measurements.
Power supply voltage:	100 / 110 / 127 / 200 / 220 / 240 VAC +/- 10%, 50 / 60 Hz
Energy consumption:	80...20 W, depending on the model
Scope of environment temperatures:	-10...+50°C for work and storage
Environment humidity:	Maximum 90% RH, without condensation
Weight:	Approximately 12 kg
Overall dimensions:	450 (width) x 140 (height) x 370 (depth) mm

Options and accessories

• resistant to corrosion internal gas circuit cables, 
• resistance to pressures up to  220 bar / 22 MPa,
• air and gas filters (also heated),
• set for stand assembly “19" type: rack,
• measuring head with an endoscope (magnifying glass for mirror surface observation during measurement),
• transport case for the device and accessories,
• additional set for temperature and gas pressure measurement,
• heated and not heated outside tubes for gas supplying,
• double sensor Pt 100 for external mirror temperature measurement,
• "ORIS" system for measurements in low humidities.

MBW Callibration Ltd. has a right to change devices and their parameters without a former notification.

Producer:

MBW Calibration Ltd.
Seminarstrasse 57
CH-5430 Wettingen
Switzerland