The ‘Calibration Standard’ of the Test Bench is “Bell Prover” which is considered a Primary (Calibration) Standard or “Sonic Nozzle” the best Flow transfer Standard, to Test & Calibrate Domestic Gas Meters (Gas Meters used in Hotels/Restaurants etc.). The device is ideal for OEMs, Calibration Laboratories & Calibration Service Providers
Bell prover helps the gas flow meter test bench to sample and calibrate the gas flow. It can test rota meters, domestic gas meters, and other forms of low range gas flow meters. The bell prover can move up and down automatically and the gas-output valve can be switched automatically.
The liquid cell inside the Bell forms a sealed space of variable but calibrated volume. When the Bell moves down into the sealed liquid, the gas in the Bell is exhausted to the flow meters (UUT) through a Flexible pipe. The exhausted gas volume will be detected compared with the cumulative in the meters. – mainly used for calibrating Domestic gas meters G1.6 to G16.
A “sonic nozzle” (also known as “Critical Flow Venturi” or “Critical Flow Nozzle”) is a flow meter that can be used as a calibration standard for gas flow meters or any flow measurement device. By design, sonic nozzles are a constant volumetric flow meter.
The nozzles are designed and manufactured to the ISO standard and as such the gas is accelerated along the Bell Mouth converging section and then is expanded in a conical diverging section, which is designed for pressure recovery.
In the throat, or minimum area point of the Sonic Nozzle, the gas velocity becomes equal to the speed of sound. At this point, gas velocity and density are maximized, and the mass flow rate is now a function of the inlet pressure, inlet temperature, and the type of gas.
Sonic nozzle produces very stable flow
Highly desirable characteristic in a flow rate
No moving parts which affects reliability
Mass Flow Varies Linearly with Inlet Pressure
Minimum Upstream Piping Required
Long Term Accuracy
Tailor made for customer’s exact requirements
Wide range of meter sizes calibratable from G 1.6 to G400 (and above)
Highly sophisticated designs to enhance operations and increase customer’s throughput
According to the UUT bell prover based or Sonic nozzle based or meter to meter comparison systems can be selected
Follows to ISO-9300 standard
Available with multiple levels of autonomy including Manual, Semi-Automatic or Fully Automatic methods of operation
| Meter Sizes | G 1.6 to G400 and above |
| Flow Rates | 1 LPM to 10000 m3/Hr |
| Lines | As required by the customer (1, 2 or 3) |
| Calibration Campaign Time | > 60 sec |
| Calibration Methods | Bell Prover Method |
| Sonic Nozzle Method | |
| Comparison Method | |
| Calibration Accuracy | 1% to 0.3% |
| Calibration Media | Air (Density correction factors can be given for other gases) |
| No. Of Units under Test | 4 at a time using bell prover and 1 or 2 according to line sizes for sonic nozzle |
| Control Console | To incorporate all process indicators. Higher powerpanel will be seperate if necessary |
| Method Of Operation | As required Manual, Semi Automatic & Automatic |
| Clamping methodes | Pneumatic only |
Pumps
Control Panel
Reducers / Expander
Valves
CollectionTanks
Weighing Scales
Storage Tanks and more
CALFLOW Software
Mounting Clamps
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