CALOMAT 7 module

Заказные данные
(1)

The CALOMAT 7 module is primarily used for quantitative determination of H₂ or He in digital or quasi-digital non-corrosive gas mixtures.

Concentrations of other gases can also be measured if their thermal conductivity differs significantly from their accompanying gases, such as Ar, CO₂, CH₄.

Область применения

Application areas

Pure gas monitoring (0 to 0.5 % H₂ in Ar)
Protective gas monitoring (0 to 2 % He in N₂)
Hydroargon gas monitoring (0 to 25 % H₂ in Ar)
Forming gas monitoring (0 to 25 % H₂ in N₂)
Gas production:
- 0 to 2 % He in N₂
- 0 to 10 % Ar in O₂
Chemical applications:
- 0 to 2 % H₂ in NH₃
- 50 to 70 % H₂ in N₂
Wood gasification (0 to 30 % H₂ in CO/CO₂/CH₄)
Blast furnace gas (0 to 5 % H₂ in CO/CO₂/CH₄/N₂)
Bessemer converter gas (0 to 20 % H₂ in CO/CO₂)

Дизайн

Structure of CALOMAT 7

Versions – parts wetted by sample gas

Gas path		Material
With pipes	Gas connection	Stainless steel, mat. no. 1.4571
	Clamping rings and union nut (set)	Stainless steel, mat. no. 1.4401
	Sample gas pipes	Stainless steel, mat. no. 1.4404
	Sensor mounting block	Stainless steel, mat. no. 1.4571
	Sensor	Si, SiO_xN_y, AU, epoxy resin, glass
	Gasket, contained in the sensor module	Perfluorelastomere FFKM

Gas path

CALOMAT 7, gas path

Способ действия

The measuring method is based on the different levels of thermal conductivity of gases. CALOMAT 7 modules work with a micromechanically produced Si chip, the measuring membrane of which is equipped with thin-film resistors.

The resistors contained in the diaphragm are regulated for constant temperature. The amperage required fluctuates in accordance with the thermal conductivity of the sample gas. This raw value determined in this way is processed further electronically to calculate the gas concentration.

The sensor is in a thermostatically controlled stainless steel enclosure in order to suppress the effect of the ambient temperature. To rule out flow influences, the sensor is mounted in a bore hole next to the flow channel.

Note

The sample gases must be fed into the analyzers free of dust. Condensation (dew point sample gas < ambient temperature) is to be avoided in the sample chambers. Therefore, the use of gas modified for the measuring tasks is necessary in most application cases.

CALOMAT 7, mode of operation

Essential characteristics

Four measuring ranges which can be freely configured, even with suppressed zero point, all measuring ranges are linear
Smallest spans down to 0.5 % H₂ (with suppressed zero: 95 to 100 % H₂) possible
Autoranging or manual measurement range switchover possible; remote switching is also possible
Storage of measured values possible during adjustments
Time constants can be selected within wide ranges (static/dynamic noise suppression); i.e. the response time of the device can be adapted to the respective measuring task.
Short response time
Low long-term drift
Measuring point switchover for up to 6 measuring points (programmable)
Measuring range identification
Measuring point identification
External pressure sensor can be connected – for correction of variations in sample gas pressure
Automatic measuring range calibration can be configured
Operation based on the NAMUR recommendation

Cross-interferences

To determine the cross-interferences of accompanying gases with several interfering gas components, you must know the sample gas composition. The following table contains the zero offsets for the carrier gas N₂ as H₂ equivalent values with 10% interference gas

Interference gas	H₂ equivalent values with 10% interference gas
CH₄	+1.77%
C₂H₆	+0.47%
C₃H₈	-0.28%
CO	-0.10%
CO₂	-0.84%
O₂	+0.19%
N₂O	-0.83%
NH₃	+1.45%
Ar	-1.22%
He	+6.32%
SF₆	-2.15%
SO₂	-1.47%
Synth. Air	+0.40%
H₂O (3%)	+0.38%

Zero offset in the system H₂ in N₂

If you are using accompanying gas concentrations ≠ 10 %, you can use the corresponding multiples of the respective table value as an approximation. This procedure applies depending on the type of gas for an accompanying gas concentration range up to approx. 25%.

The thermal conductivity of most gas mixtures has a non-linear response. Even ambiguous results can occur in specific concentration ranges, e.g. with H₂ in He mixtures.

In addition to the zero offset, the accompanying gas also affect the characteristic curve. For most gases, however, the effect on the characteristic curve is negligible.

Особенности

Small T₉₀ time due to micromechanical-produced Si sensor
Universally applicable hardware basis, high measuring range dynamics (e.g. 0 to 0.5%, 0 to 100%, 95 to 100% H2)
Open interface architecture (analog, digital, Ethernet)
SIMATIC PDM network for maintenance and servicing information (optional)

Схема подключения

Gas connections

CALOMAT 7 gas connections

The sample gas connections are made of stainless steel with material no. 1.4571 and are designed as connecting fittings with a pipe diameter of 6 mm.

Технические данные

The technical specifications are based on the definitions of DIN EN 61207-1.

Unless specified otherwise, the data listed below relates to the following measurement conditions:

Ambient temperature	25 °C
Atmospheric pressure	Atmospheric (approx. 1 000 hPa)
Sample gas flow	0.6 l/min (or Nl/min)
Reference application	H₂ in N₂^*
Site of installation	Vibration- and impact-free

* The technical specifications for time and measuring response as well as for the influencing variables can sometimes differ significantly for other gas mixtures

General information
Weight	Approx. 3 kg
Measuring ranges
Number of measuring ranges	Max. 4; parameters can be assigned freely
Parameters can be assigned in the measuring ranges
Smallest possible span	0.5% H₂ in N₂
Largest possible span	100% H₂ in N₂
Smallest possible span with suppressed zero point	5% (e.g. 95% to 100%) H₂ in N₂
Gas inlet conditions
Sample gas pressure	700 to 1200 hPa (abs.)
Pressure drop between sample gas inlet and sample gas outlet	< 50 hPa at 1.5 l/min
Sample gas flow	30 to 90 l/h (0.5 to 1.5 l/min)
Sample gas temperature	0 to 70 °C
Sample gas humidity (rel. humidity)	< 90% (condensation inside the gas path is to be avoided)
Sample chamber temperature
Standard version	Approx. 72 °C
Time response
Warm-up period at room temperature	< 30 min (max. accuracy after 2 h)
Response characteristics
Delay display T₉₀ with device-internal signal damping (low pass filter) of 1 s	< 2.5 s
Dead time (T₁₀) at 1 l/min	< 0.5 s
Adjustable signal damping range	0 to 100 s
Measuring response
Output signal fluctuation with device-internal signal damping of 1 s	≤ ± 0.5% of the smallest span acc. to nameplate (σ < ± 8.33 vpm H₂)
Detection limit	≤ 1% of the smallest measuring span according to nameplate
Measured-value drift	≤ ± 1%/week of smallest span according to nameplate or ≤ 50 vpm H₂ / week, whichever is greater
Repeatability	≤ ± 1% of the current measuring span or 100 vpm H₂
Linearity error	≤ ± 1% of the current measuring span or 100 vpm H₂
Influencing variables
Ambient temperature	≤ ± 0.5%¹⁾/10 K of the current measuring span or ≤ ± 50 vpm H₂ / 10 K
Sample gas pressure	≤ ± 0.5 %¹⁾ of the current measuring span/1% pressure variation or ≤ ± 50 vpm H₂ / 1% pressure change
Sample gas flow	≤ ± 0.2% of the smallest possible measuring span with a change in flow of 1 dl/min within the permissible flow range
Accompanying gases (interference gases)	The interference gas sensitivity depends on the application and must be determined in each case except for applications with blast furnace gas / converter gas / wood gasification (pre-adjusted).
Supply voltage	≤ ± 0.1% of full-scale value (within the nominal range of use)
Electrical inputs and outputs
Analog and digital interfaces	See base unit
Climatic conditions
Storage and transport	-30 to 70 °C
Permissible ambient temperature (during operation in base unit)²⁾	0 to 50 °C
Relative humidity (RH) during storage, transport or operation	< 90% (condensation from the installed components is to be avoided)
Gas connections
Connection fittings	Pipe connection with 6 mm outer diameter
Materials of wetted parts
Gas connection	Stainless steel material no. 1.4571
Clamping rings and union nut (set)	Stainless steel material no. 1.4401
Sample gas pipes	Stainless steel material no. 1.4404
Sensor mounting block	Stainless steel material no. 1.4571
Sensor	Si, SiO_xN_y, Au, epoxy resin, glass
Gasket, contained in the sensor module	Perfluorelastomere FFKM

¹⁾ Values less than the detection limit are not useful

²⁾ Restriction for installing an ULTRAMAT 7 module: 5 to 45 °C

Дальнейшая информация

Ordering example

CALOMAT 7 module built into wall box
7MB3000-3AX00-1AA0-Z+D12
7MB3040-0XX00-0BB0-Z+D12