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GasCVD Natural Gas Calorimeter
Model CVM400
No.SS2-CVM100-0100
OVERVIEW
The CVM400 GasCVD Natural Gas Calorimeter measures the thermal conductivity of a gas mixture such as natural gas at different temperatures and calculates the calorific value of the gas based on its thermal conductivity.
Drawing upon expertise in gas analysis and gas calorific value measurement accumulated for more than 20 years since the release of the first Smart Gas
Chromatograph, Azbil Corporation now offers compact, lightweight, and high-precision natural gas calorimeters that comply with international legal metrology standards.
FEATURES
(1) OIML R 140 compliant device. Can be used as a calorimeter or calorific value determining device (CVDD) for natural gas. (OIML R140: International Organization of Legal Metrology recommendation that includes specifications for CVDDs.)
(2) Innovative structure compatible with various installation sites
• Unlike conventional gas calorimeters, the CVM400 is small and lightweight, allowing a variety of installation site choices.
• Explosion-proof: compliant with IECEx and ATEX, and suitable for Zone 1 use
(3) Revolutionary continuous measurement. Can detect a change of calorific value in processes in near real time by measuring every 2 seconds.
(4) Fast response (sample flow rate: 50 ml/min)
• Natural gas model: 5 seconds (When caloric value changes more than 0.7
MJ/m 3 )
• OIML model: 30 seconds
• LNG model: 5 seconds
Response time is defined as the time output signal changes to 90 %.
(5) Automatic calibration for prolonged stability. Automatic calibration using pure methane guarantees long-term stable operation.
(6) A wealth of diagnostic functions
• Ambient temperature diagnostic function. Determines whether the operating environment is suitable, making use of a temperature sensor embedded on the same chip as the thermal conductivity sensor.
• Operation time tracker function. Keeps track of the total operation time for comparison with the recommended replacement period (70000 hours) for the calorimeter.
• Automatic calibration history check function. Shows up to 5 of the latest automatic calibration records to check changes in the calibration factor.
MEASUREMENT PRINCIPLE
The CVM400 measures the thermal conductivity of natural gas at different temperatures, changing the temperature of the thermal conductivity sensor in multiple stages. The calorimeter uses the support vector regression (SVR) method that is also employed on Azbil Corporation’s differential pressure transmitters. The calorific value is calculated from the measured thermal conductivity values of the process using a characteristics formula created in advance based on thermal conductivities measured at different temperatures of the natural gas.
STANDARD SPECIFICATIONS
Instrument
Process gas connection port: NPT 1/8 (F), Rc 1/8
Electrical conduit: NPT 1/2 (F), M20
Case structure: IEC IP66
ATEX: II 2G Ex d II B T6 Gb;
II 2D Ex tb IIIC T80 °C Db
IECEx: Ex d IIB T6 Gb, Ex tb IIIC T80 °C Db
TIIS: Ex d IIB T6X
KOSHA: Ex d IIB T6
Display:
Calorie display:
% display:
LCD
5 digits setting range is shown by a % and by a bar graph
Automatic calibration setting display:
and light up alternately when set.
Calibration factor display: a flag is shown if calibration fails
Communications: HART protocol ver. 7.0 (with CommStaff and HART 475
Communicator)
Power:
Output:
Contact output:
24 Vdc ±10 %, 0.3 A max. (inrush current at startup)
Analog output: 4–20 mAdc
24 Vdc ±10 %, 50 mA max. (transistor contact for status); 24 Vdc ±10 %, 1 A max. (transistor contact for calibration)
Baked acrylic resin finish Paint:
Color:
Housing: Light beige
Front cover: Dark beige
Terminal cover: dark beige
1 6th edition
Material
Case material:
Housing: aluminum alloy (ADC 12)
Front cover: aluminum alloy (ADC 12)
Terminal cover: aluminum alloy (ADC 12)
Window: reinforced glass
Cover O-ring: NBR rubber
Wet parts materials:
Manifold:
Adapter:
304 stainless steel
304 stainless steel
µTCD sensor: platinum, glass, gold, Kovar, silicon
O-ring: Fluoro rubber
Process gas specifications
Temperature: –10 to +50 °C
Pressure: 110 kPa (abs) max. (at GasCVD process connec-
Flow rate:
Dust:
Mist:
Moisture: tion port inlet)
50 ±10 ml/min
Less than 1 µm in diameter, 1 mg/m 3 max.
none at –20 °C dew-point temperature –20 °C max.
Calibration conditions
Calibration: Automatic/Manual
Calibration gas: Pure methane (99.995 purity min.)
Installation conditions
Ambient temperature: –10 to +50 °C
Ambient humidity: 95 % RH max.
Mass: 2.5 kg
Table2. Performance/Unit: %RD(%reading)
Variations
*2
Accuracy
Repeatability
*1
*2
Ambient temp.
*3
Atmospheric press.
*4
Sample gas flow *5
Natural gas
Code A Code F
Natural Gas
±1.5 % RD
±0.2 % RD
±0.4 % RD
±0.2 % RD
±0.2 % RD
LNG
Code G
OIML R140
±1 % RD
LNG
±1 % RD
±0.2 % RD ±0.2 % RD
±0.4 % RD ±0.2 % RD
±0.2 % RD ±0.2 % RD
±0.2 % RD ±0.2 % RD
*1: Accuracy=(Trueness)+(Repeatability)
• Trueness is the proximity of measurement results to the true value.
• True value is the value calculated by the components according to ISO6976:1995.
*2: Repeatability=σ*2√2. σ:Standard deviations of the measurement value.
*3:Ambient temperature effect per 30 °C change. Range from -10 to +50 °C.
*4: Static pressure effect per 30 hPa change. Range from 983 to 1043 hPa.
*5: Sampling gas flow rate effect per 10 ml/min change. Range from 40 to 60 mL/min.
1
4
6
2
3
5
Table3. Output range (LRV-URV)/Unit: MJ/m 3
15 °C /15 °C
20 °C /20 °C
25
0
°C /20 °C
°C /0 °C
25 °C /0 °C
15 °C /0 °C
1 SCV
Natural Gas
35-45
4 WI_Hs 46-56
7 ICV 31-41
A WI_Hi 41-51
1 SCV 37-47
4 WI_Hs 48-58
Natural gas
Code A Code F
OIML R140
35-45
7 ICV 33-43
A WI_Hi 43-53
SCV: Superior Calorific Value: MJ/m 3
WI_Hs: Wobbe Index (SCV/√Relative density) MJ/m 3
ICV: Inferior Calorific Value: MJ/m 3
WI_Hi: Wobbe Index (ICV/√Relative Density): MJ/m 3
LNG
Code G
37-47
48-58
33-43
43-53
39-49
50-60
35-45
45-55
LNG
Table1. Acceptable limits of components /Unit: mol %
Code A
Natural gas
Code F
CH
4
(C1) Methane
C
2
C
C
4
3
H
6
H
8
(C2) Ethane
(C3) Propane
+(C4+) Butane+higher
*
N
2
CO
2
Condition alkanes
Nitrogen
Natural Gas
80 to 100
0 to 11
0 to 5
0 to 2
0 to 7
Carbon Dioxide 0 to 2
C1>C2≥C3≥C4+
OIML R140
80 to 100
0 to 11
0 to 5
0 to 1.2
0 to 7
0 to 2
C1>C2≥C3≥C4+
0.4*C2≥C3
0.6*C3≥C4+
0.4*C2≥C3
0.6*C3≥C4+
CO
2
≥1→C4+≥0.3
C4+-CO
2
≤0.6
(Except in case
1<C4+≤2*CO
2
)
CO
2
≥1→C4+≥0.4
CO
2
≤3→C4+≤0.35
LNG
Code G
LNG
85 to 100
0 to 14
0 to 4
0 to 2
0 to 1
0
C1>C2≥C3≥C4+
C1≥95→N
2
: 0 to 1
C1<95→N
2
: 0 to 0.2
*Butane must be higher than pentane+higher alkanes, C4>(C5+C6 )
2
図1.
Figure 1. Example of recommended GasCVD installation
3
Handling Precautions for This Product
Installation Precautions
WARNING
When installing, use proper fittings and proper tightening torque for connections to the process and to the exhaust. Gas leakage is dangerous because process gas and calibration gas are flammable. Please refer to the leak check instructions in this manual and verify that there is no gas leakage.
Do not use the product except at the rated pressure, specified connection standards, and rated temperature. Use under other circumstances might cause damage that leads to a serious accident.
For wiring work in an explosion-proof area, follow the work method stated in the explosion-proof policy.
Both the process gas and calibration gas (pure methane) are flammable, and if mixedwith air and ignited, they may explode.
For safety, do the following before beginning to work.
Use gas detector to make sure that no flammable gas can be detected in the work area, instrument, or surrounding air. We recommend the continued use of the gas detector during work.
CAUTION
After installation, do not step or stand on this unit. Doing so may damage the device or cause injury.
Bumping the glass of the display with a tool may cause damage or injury. Be careful.
Install the device correctly. Incorrect or incomplete installation will cause output errors and violation of regulations.
This product is quite heavy. Protect your feet with safety shoes when working.
Do not subject the product to shock or impact.
The outlet of the GasCVD should be connected to ventilation tube with an inner diameter lange enough not to be affected by backpressure. It should open to the air in a place not affected by wind, rain or snow.
Natural gas and methane are discharged directly from the vent, so the vent should be located where human beings will not be harmed.
When cleaning the inside of the tube by blowing back clean inert gas, to protect the device, do not blow gas into GasCVD.
Wiring Precautions
WARNING
Do not do wiring work with wet hands or while electricity is being supplied to the product. There is a danger of electric shock.
When working, keep hands dry or wear gloves, and turn off the power.
CAUTION
When wiring, check the specifications carefully and make sure to wire correctly. Incorrect wiring can cause device damage or malfunction.
Supply electric power correctly according to the specifications.
Supplying power that differs from the specifications can damage the device.
Use a DC power supply that has overload protection.
Never open the case cover while the GasCVD is ON in a hazardous location.
Handle the GasCVD with care. It may lose its explosion-proof performance due to corrosion.
Explosion-proof performance is not guaranteed unless the case is LOCKED. Always tighten the case cover completely and lock it.
Maintenance Precautions
WARNING
When removing this device for maintenance, be careful of residual pressure or residual process gas. Leakage of process gas is dangerous.
When working on the vent, check its direction so that people do not come into contact with vented gas. There is a danger of burns or other physical harm.
When the device is being used in an explosion-proof area, do not open the cover. Opening the cover may cause an explosion.
CAUTION
This product was kept under carefully controlled conditions until it was shipped. Never try to modify this device. Doing so could damage it.
Precautions for Using Communication Devices
When using a communication device such as a transceiver, cell phone, PHS phone, or pager near this device, observe the precautions below. Otherwise, depending on the transmission frequency, this device may not function properly.
Determine beforehand the minimum distance at which the communication device will not affect the operation of this device, and maintain a separation greater than that distance.
Make sure the cover of its transmitter section of this device is closed before using the communication device.
Precautions for Communication
If transmitter output is reduced to 3.2 mA or less because of burnout, etc., communication with a HART communicator may not be possible. Try turning off the power, rebooting, and restarting communication.
Hazardous Area Certifications
GasCVD complies with the types of protection that are based on the standards listed below.
4
Model number table
CVM400 -
Process connection
Electrical conduit connection
Accuracy
Explosion-proof structure
Communications
Gas type
1/8 NPT (F)
Rc 1/8
1/8 NPT (F)
M20
Always "A"
ATEX Flameproof
IEC flameproof
KOSHA flameproof
1
3
1
2
TIIS flameproof
Water proof
HART
Natural gas
OIML R140 CVDD compliant *1 *2
LNG
A
K
J
E
G
W
H
A
F
G
Indicator
Paint
Gas caloric value calculation parameters
Output units
Without Display
With Display
Standard finish
Corrosion-proof finish
15 °C /15 °C
0 °C /0 °C
25 °C /0 °C
20 °C /20 °C
15 °C /0 °C
25 °C /20 °C
SCV MJ/m 3
WI_Hs MJ/m 3
ICV MJ/m 3
WI_Hi MJ/m 3
X
A
Note) *1: The code 1 “ 15 °C /15 °C” of the gas caloric value calculation parameter should be selected.
*2: The code 1 “ SCV MJ/m 3 ” of the output units should be selected.
*3: The certification sheet for gas cylinder is not included.
X
B
3
4
1
2
5
6
1
4
7
A
-
X No
1 Test report
2 Traceability certificate *3
3 OIML/MID certificate
4 Material certificate
5
Dimensions
86 120 130 [Unit: mm]
67
103
2-M8×1.25
Depth 8
45
°
58
35
6
7
Please, read ‘Terms and Conditions’ from following URL before the order and use.
http://www.azbil.com/products/bi/order.html
Specifications are subject to change without notice.
1-12-2 Kawana, Fujisawa
Kanagawa 251-8522 Japan http://www.azbil.com/
(11)
8
1st edition: Jan. 2012
6th edition: July 2015
No part of this publication may be reproduced or duplicated without the prior written permission of Azbil Corporation.
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