- 800 Series Turbine Flowmeters
- 900 Series Turbine Flowmeters
- 1000 Series Turbine Flowmeters
- Hall effect detection Turbine Flowmeters
Turbine Flow Meters: Installation Notes
The principle of operation is very simple. A jet of liquid is directed at a free running Pelton wheel turbine in a specially shaped chamber. The rotation of the rotor is detected with a Hall Effect sensor. The output frequency of these pulses is directly proportional to flow rate and the total number of pulses the total volume passed. The standard bearing material is sapphire as this gives a long trouble free life to the meter. Non-metallic options mean that these meters may be used with very aggressive chemicals and ultra-pure water.
Turbine Flow Meter: Instruction Sheet
The pipe work must be designed in such a way to eliminate reverse flow, and the flow passes through the meter in the direction of the arrow. The meter should be installed in a position that prevents it from draining down as on start-up serious damage could result by “impacting” an empty flowmeter with a high velocity fluid stream. The fluid should be clean and homogenous.
In all cases an upstream filter of at least 80 microns must be fitted. It is recommended that before the flowmeter is installed in the line a “dummy” section of pipe is inserted and the system flushed. This is to eliminate any debris in that section of the line. The pipe must not stress the body of the meter and should be fully supported either side with appropriate isolation valves and in some cases a by-pass valve. When screwing fittings into a threaded body always place the second spanner next to the fitting being inserted, never tighten one fitting against the other across the meter body as this will distort the body and damage the sapphire bearings.
On initial start-up increase the flow slowly to ensure no over speeding of the meter occurs as the air is forced from the line. This is best achieved by monitoring the flow rate and ensuring that a 50% over-range is not exceeded. Never blow a flowmeter with an airline. Care should be taken to ensure that no air enters the system (e.g. leaky pump gland) or that no cavitation takes place. With a volatile liquid we recommend at least twice the vapour pressure plus 1 Bar as the operating back pressure. The user must ensure that the materials of construction are compatible with their fluid. We accept no responsibility for material compatibility; it is the users’ responsibility.
Turbine Flow Meter: commissioning
- If problems occur during commissioning always check the fundamentals first.
- Is the flowmeter/instrument the correct one for the installation?
- Is the power connected to the meter and the instrument, and is it turned on?
- Is the instrument set/wired correctly? I/P port, pulse type, frequency span, units etc.
- Where possible check the O/P from the flowmeter with an oscilloscope before proceeding
- Was the line flushed prior to installing the meter?
- Was the flow increased slowly?
- Is the meter blocked?
Hall effect sensor
Supply 4.5 – 24Vdc
Temp range -20 to 125°C
Rise & fall times 1.5uS max
Supply current 7.5mA typ
Switch current 10mA max
If you cannot find a solution ask your supplier for technical support.