Home FAQ's
Technical FAQ's:

1. Why back pressure is necessary?

Ans - When measuring liquids, back pressure in the flow line should be sufficient to prevent cavitation. Cavitation occurs due to pressure drop at the obstruction in the flow line. Due to pressure drop, bubbles are formed and are driven to the further locations in the flow line where they break and erode the parts of flow line. To avoid such cavitations, the back pressure in the line must be always greater than the vapor pressure of the fluid. To maintain back pressure in the line, larger pumping force is required. In case of water and liquids of similar vapor pressure, required back pressure is approximately 1 kg/cm at velocity of 6 meter/second. When there is no back pressure in the pipeline, it can be created by placing a partially closed valve on the downstream side of the flow meter.

2. Why upstream and downstream straight length is required?

Ans - A. Flow Meter accuracy is guaranteed for a fully developed flow profile in the pipeline at the installed location. Normally from flow disturbance point, flow is developed after a distance of about 20D or more. Hence minimum upstream straight length should be 20D for normal pipelines. Please refer Table for Upstream/Downstream Piping Length for pipelines with other types of piping geometry like elbows, tees, bends or obstructions like valves, etc.
Minimum downstream straight length should be 5D from the flow meter to avoid disturbances in the flow.

3. What is CFM, SCFM, ACFM, Am/hr and N m/hr?

Ans -

  • CFM is a unit of flow rate (cubic feet per minute)
  • SCFM is a unit of flow rate (Standard Cubic Feet per Minute) at STP condition i.e. standard temperature 60 F and standard pressure 14.69 A PSI.
  • ACFM (Actual Cubic Feet per Minute) is the actual flow at the operating temperature and pressure conditions.
  • Am/hr (Actual Cubic Meter per hour) is the actual flow at the operating temperature and pressure conditions.
  • Nm/hr (Normal Cubic Meter per hour) is normalized value of flow at NTP conditions i.e. flow at Normal Temperature 0 C and Normal Pressure 101.32 kPa condition.
  • Note : STP/NTP conditions are decided by different organizations/authorities as per their specifications.

Product FAQ's:

1. Do you wet calibrate the meters? What facilities do you have for calibration?

Ans - Wet calibration is not required for INCONEL Vortex Flow Meters. Our meters are factory calibrated (bench calibrated) by highly accurate, precision electronic equipments in compliance with National and International standards. Our flow meters have been tested and certified by FCRI (Fluid Control and Research Institute), the premier institute in Asia for calibration tests. Wet testing calibration certificate can be made available on special request.

2. Which cable should be used to connect Transmeter?

Ans - We recommend three-core, twisted and shielded, 19/36 gauge cable. In applications requiring mechanical ruggedness, we recommend three-core 1.5 mm armored (shielded) cable.

3. Why are INCONEL Vortex Flow Meters more accurate?

Ans - INCONEL Vortex Flow Meters have an accuracy of 1% or better, of measured value. The Flow Meter has linear characteristics throughout its measurable flow range.

4. Can we install the flow meter in vertical/inclined pipeline?

Ans - Yes, the flow meter can be installed in a vertical, inclined or in any angular position of pipeline for compressible fluids like low pressure air/gas, compressed air/gas.
For liquid applications in a vertical pipeline, the direction of flow should necessarily be from bottom to top, so as to avoid flow separation phenomenon.

5. Why is a ground strap required?

Ans - Ground strap is required for proper grounding (Earth) of meter body, i.e. both pipe and meter body should be at the same voltage potential.

6. Which gaskets are recommended?

Ans - For general applications asbestos grade or any non-yielding gaskets are required (Champion #20 or equivalent). NEVER use rubber gaskets!!!
Gasket I.D. must be 5mm larger than the meter I.D. Gaskets must be non-yielding so that they do not protrude and obstruct the flow. For high temperature applications please Contact Us.

7. Where should we place the taps for pressure gauges and temperature gauges?

Ans - Pressure gauge should be located within a distance of 4D to 7D on either upstream or downstream of the meter body. Pressure tap fittings must not protrude in the pipe. Tap holes must be burr free.
RTD Temperature tap must be placed on the downstream side of the flow meter and within a distance of 5D to 10D from the flow meter body (since a temperature measuring probe /thermo-well can interfere with vortex generation)

8. Can I connect flow Transmeter directly to PLC, DCS or other Instruments?

Ans - No, we recommend using ONLY INCONEL "Flow Rate Indicators" with our flow Transmeter. Using any other type of indicator may damage the flow Transmeter.
However, you may connect INCONEL "Flow Rate Indicators" to PLC, DCS or other Instruments, RS-232 or RS-485 output is available and also Isolated passive two wire 4-20 mA DC current output is available from the back panel connections of INCONEL "Flow Rate Indicators".

9. Is the Flow Meter multi-variable?

Ans - No, the flow meter measures only the actual flow at operating pressure and temperature conditions i.e. AM/HR or ACFM.

10. Can I use flow meter without the provided indicator? Do you have local flow indication?

Ans - INCONEL Vortex Flow Meters do not employ local flow indication but are part of a complete system consisting of the Flow Meter itself and a remotely mounted Rate of Flow Indicator/Totalizer.

11. Can I service/ repair the flow meter myself?

Ans - Our flow meters do not require any routine maintenance and are practically maintenance-free. There are no user serviceable parts in the flow meter system. Should you require any assistance please contact us using the Service Request Form available at the back of your Installation Manual.

12. How do I pack the flow meter to send for servicing if required?

Ans - The Flow Meter system should be packed using adequate (2"-3" thick) thermocol on all 6 sides inside a plywood box to avoid any transit damages.
Flow Meter and Flow Indicator should be packed in separate boxes.
"Used Goods / Goods for Repairs" Declaration should be accompanied with the consignment. Please Contact Us for declaration format if required.