Flowmeters and System Solutions

Flowmeters and System solution.





The EL4801 calorie computer is a digital instrument designed with the latest electronic technology to fulfill the demand for faster calorimetry. The EL4801 calculates the calorific value of natural gas or city gas using the sonic velocity measured by an ultrasonic flowmeter. This instrument is also capable of simultaneous flow rate calculation by the flow velocity measured with the ultrasonic flowmeter.
Densitometers are commonly used for calorimetry of city gas and natural gas that does not include inert gas by using the correlation between molecular weight (density) of the gas and calorific value. This calorie computer, however, calculates calorific value by utilizing the correlation between molecular weight and sonic velocity as well as the correlation between process temperature/pressure and calorific value as computational logic.
This calorie computer was co-developed with Osaka Gas Co., Ltd.

Note: This computer is a dedicated computer for the ultrasonic flowmeter of OVAL product.

Product Specifications


1. One-second (approx.) response and accurate calorimetry
The computational logic based on actual measurement values enables fast and accurate measurement.
2. Simultaneous measurement of calorie and flow rate
By measuring sonic velocity and flow velocity, both calorie and flow rate can be calculated at the same time.
3. No ancillary equipment cost required
As long as an ultrasonic flowmeter is installed on the process side, no ancillary equipment, gas decompression, or diffusion/ recovery is necessary.
4. Indicated values can be saved for an extended period to an external storage such as USB memory.
5. Up to four measurements out of temperature, pressure, calorific value, specific gravity, and flow rate are available for analog output (4-20mA/1-5V).

Major specifications

General Specifications

Guaranteed calorie range 39 to 50 MJ/m3(normal)
Operating temperature range 0 to 50°C*1</span(Recommended range: ±10°C of calibration point*2)
Operating pressure range 0.2 to 5 MPa [G]
5 to 10 MPa [G]
Calorimetric accuracy ±0.25MJ/m3(normal)
Response time Minimum 1 Sec.

*1: At low temperature, measured gas may condensate. Please take necessary measures to prevent gas condensation in the process.

*2: “Calibration point” refers to the measuring conditions during on-site calibration, including temperature, pressure, and calorific value of the gas.
• Due to the principle of measurement, we recommend re-calibration to prevent meter error in case temperature, pressure, or gas composition fluctuates drastically from the
calibration point.
• Indicated calorific value may fluctuate as the result of thermometer or pressure meter alteration, or change in gas composition. In case the fluctuation of indicated calorific value exceeds the calorimetric accuracy, please confirm the reproducibility of the process.
• Interfusion of inert gas (N2, CO2, etc.) may cause meter error.
• Consult OVAL when using at the temperature lower than 0°C.

Computer Specifications

BOX-PC BX-710P2-AC5411(Brand: CONTEC)
CPU Celeron (R) processor 1.06GHz (FSB533MHz)
Main memory 1GB (200 pin SO-DIMM x1)
OS Windows Embedded Standard 2009
Input signal Temperature input
Pressure input
A/D converter board PCI−3178 (Brand: interface)
Insulation system Channel-to-channel independent insulation input
Input range 1 to 5V, 4 to 20mA*1
Resolution 16bit
Input impedance 2GΩ(TYP)
Relative accuracy ±4LSB(at25°C)
Inaccuracy (Max.) ±0.15% (0 to 50°C)
Output signal Select 4 outputs from calorific value, flow rate, specific gravity, temperature and pressure. D/A converter board PCI−3347 (Brand: interface)
Load resistance when current output:450Ω Max.
Load capacity 450pF or less
Insulation system Channel-to-channel insulation output
Output range 4 to 20mA, 1 to 5V*1
Resolution 16bit
Relative accuracy ±8LSB(Max.) (at25°C)
Error (Max.) ±0.10% of SPAN (Max.) (0 to 50°C)
Alarm output Allowable load AC250V 5A DC30V 5A 1 output normal open, normal close
Display mode LCD unit 6.5 inches (640 x 480) color TFT (260 thousand colors) (touch-sensitive panel equipped)
Display items Temperature 2 digits after a decimal point (°C etc.)
Pressure 2 digits after a decimal point (MPa [abs])
Sonic speed 2 digits after a decimal point (m/s etc.)
Heat quantity 2 digits after a decimal point (MJ/Nm3etc.)
Flow Nm3/h etc.
Specific gravity 4 digits after a decimal point
Annunciation of abnormality Error Messages
Indicator Display update, Communication, Logging
Operation mode RUN MODE Calorie computing display mode (Update interval of computing and displaying: 1 sec.)
SET MODE Parameter setting mode
Data logging Interval: 1 to 600 sec. (Number of data entries: depends on the capacity of external USB memory)
Communication RS485 (to communicate with ultrasonic flowmeter)*2
External input Display unit front touch-sensitive panel (touch pen equipped), USB (connectable to keyboard and/or mouse from front side)
External storage Connectable to USB port (USB memory, etc.)
Fan service life Approx. 8.5 years (24hours operation per day, environment at 30°C)
Power supply 100 to 120VAC, 200 to 240VAC
Ambient temperature 0 to 50°C
Power consumption 80VA Max.
Installation Panel mount type
Finish Mat black
Weight Approx. 20kg
Accessories 1 touch pen, 1 fuse, and 4 unit fittings

*1: Available by connecting a 250Ω accurate resistance to the terminal block.

*2: Only an OVAL ultrasonic flowmeter is connectable.


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Product Specifications