Titan Flowmeters: Oval Gear Flow Sensor Installation

These instructions cover the following oval gear flow sensor products and options

oval gear flowmeter instructions

Oval Gear Flowmeter Instructions: Covering OG1 – OG7 oval gear flow sensors, aluminium, stainless steel or peek oval gear flowmeters, flanged or screwed options, reed switch, hall effect and IS sensor option.

OG1 (Oval Gear Flowmeter, up to 1 Litre per minute)
OG2 (Oval Gear Flowmeter, up to 4 Litres per minute)
OG3 (Oval Gear Flowmeter, up to 10 Litres per minute)
OG4 (Oval Gear Flowmeter, up to 50 Litres per minute)
OG5 (Oval Gear Flowmeter, up to 100 Litres per minute)
OG6 (Oval Gear Flowmeter, up to 200 Litres per minute)
OG7 (Oval Gear Flowmeter, up to 500 Litres per minute)
OG Flow Sensors: Aluminium, Stainless steel & PEEK™
Flanged or screwed Oval Gear Flow Sensors
Reed switch OG (PD) Flowmeters
Hall effect OG (PD) Flowmeters
OG Flowmeter with IS Sensor option





The pipe-work of the oval gear flow sensor should be designed in such a way to eliminate reverse flow. 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. 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.

Oval gear flow sensors work by using the low differential pressure generated across the body to drive a pair of oval gears. This rotation can be detected by a variety of means to give either a TTL (NPN transistor) or contact closure pulse output. The unit is manufactured in a choice of materials and pressure ratings to suit most applications and as with all positive displacement flowmeters, the performance improves with increasing viscosity achieving an accuracy of ±0.1% of reading with higher viscosities. The standard meters can be used up to 1000 cP; above this viscosity specially profiled gears MUST be used.

Titan Flowmeters: Oval Gear Flow Sensor Electrical Characteristics


Hall Effect sensors


Reed switch
Supply voltage 8 to 24Vdc Contact material: Rhodium
Voltage 24Vdc max
Current 100mA max
Operations 109‘R’ Series resistor 560 ?.
For hazardous areas ‘X’ no
protection is fitted.
Temp range -40 to 150°C
Rise & fall times 1.5uS max
Supply current 7.5mA typ
Switch current 10mA max
Leakage current 10uA max

It is recommended that all “signal” cables are screened and run separately to power lines and switched inductive loads and are located well away from inverters and other “noisy” apparatus. Always use sound wiring practice. Hall effect detector (NPN) requires an external pull-up resistor connected between the output and a suitable power supply to attain a pulse. Typically the flowmeter PSU may be used but sometimes a dc pulse, which is of a different voltage, may be required e.g. using a PLC with a 24V PSU and an internal 5V rail for the pull-up resistor/ pulse input. The reed switch has a protection resistor of 560 Ohms in series with the connections unless it is specified for hazardous areas when the resistor is excluded.

Titan OG (PD – Positive Displacement) Flow Sensor commissioning

If problems occur during commissioning always check the fundamentals first:

  • Is the flowmeter/flow 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?

If you cannot find a solution ask your supplier for technical support

E.g. A 50 l/min. flow sensor measuring 40,000 cps would have a maximum flow range of 30% of full scale i.e. 15 L/Min. All meters working above 1000 cps must have specially profiled gears.



Oval Gear Flow Sensor/Meter Assembly

oval gear flow meter assembly

Oval Gear Flow Sensor/Meter Assembly