Manufacturer: Yokogawa Electric Corporation

Yokogawa pH sensor FU20-05-T1-NPT

Features

Yokogawa’s family of wide body sensors is suited for a wide variety of processes. The sensors share the same unique features:
? Long life double junction Ag/AgCl reference system with polymerized saturated KCI fill including AG+ ion trap.
? PTFE reference diaphragm to prevent fouling and reduce measurement error.
? Integral Pt1000 element for accurate temperature measurements
? Double junction combined with ion-trap to prolong the life of the reference probe even in chemically unfavorable environments.
? Platinum ORP/LE electrode for accurate simultaneous pH and ORP measurements.
? Versatile in-line, immersion or off-line installation.
? Polymerized electrolyte to extend the sensors life time.

For general purpose applications the FU20 is the sensor of choice:

Yokogawa pH sensor FU20-05-T1-NPT

The FU20 combination sensor exemplifies Yokogawa motto, “Simply the Best” sensor technology. The wide body sensor (26 mm diameter) holds four separate measuring elements in one unbreakable and chemical resistant PPS 40GF (RytonTM) body. Installation is simple with the integrated industrial 3/4” tapered thread. Temperature fluctuations are compensated for extending sensor life. The FU20 is targeted at those applications where simplicity, accuracy and reliability are required for pH or redox(ORP) measurements. This means that in 90% of the known applications this sensor will be an excellent choice.

For more difficult applications the FU24 sensor will be the better choice:
The FU24 is also made with a chemical resistant PPS 40GF body. It is particularly useful in harsh applications with fluctuating pressure and/or temperature. These processes shorten sensor life because the process fluids move in and out of the sensor under influence of frequent pressure and/or temperature fluctuations. This results in fast desalting and dilution of the reference electrolyte which in turn changes the reference voltage causing a drifting pH measurement.

By incorporating the successful Yokogawa patented Bellow system integrated in the FU24 electrode, a strong pressure
compensation mechanism is created. The built-in bellow ensures immediate interior pressure equalization to the outside pressure, making the sensor virtually insensitive to external pressure variations.

A slight overpressure caused by the bellow tension, prevents fluid ingress and maintains a positive ion flow out of the sensor. This feature is of particular interest in pure water applications.

In applications where chemical resistance is a vital issue the PH20 will be the choice:
The PH20 body is made of chemically resistant PVDF. The sensor is nicknamed “Tempress” because of the patented
compensation for changes in the process temperature and pressure. A simple mechanical feature makes the sensor more
accurate, and gives it a longer lifetime. The compensation panels flex to accommodate changes in pressure and temperature, thus avoiding large differential pressures across the diaphragm. This prevents most problems associated with the reference junction.

Both FU20 and FU24 are also available with VP connector. This makes installation easier. All sensors are delivered with a Quality Certificate.

General Specifications FU20

Yokogawa pH sensor FU20-05-T1-NPT

Measuring elements : pH glass electrode
: Silver chloride reference system
: Platinum electrode
: Pt1000 temperature sensor.

Construction materials
Body : PPS 40GF (glass filled Ryton)
Earthing pin : Solid platinum
O-ring : None
Reference junction : Porous PTFE
Cable : Coaxial with 4 extra leads
Sheet material : Thermoplastic rubber
Measuring Sensor : G-Glass

Functional specifications (at 25°C)

Yokogawa pH sensor FU20-05-T1-NPT

Isothermal point : pH 7
Reference system : Ag/AgCl with saturated KCI
Glass impedance
- Dome shape : nominal 200MΩ, G-glass
- Flat Surface : nominal 700MΩ, G-glass
Junction resistance : 1 to 10 kΩ
Temperature element : Pt1000 to IEC 751
Asymmetry potential : 8 ± 15 mV
Slope : > 96 % (of theoretical value)

Dynamic specifications (at 25°C)
Response time pH step (7 to 4): < 15 sec for 90%
Response time temp step (10°C)
- Dome shape : < 1 min for 90%
- Flat surface : < 1.5 min for 90%
Stabilisation time (0.02 pH/10 s): < 2 minutes

Operating range
pH : 0 - 14*
Temperature : -10 to 105oC (14 to 221 °F)
Pressure : 0 to 10 bar ( 0 to 145 PSIG)
Conductivity : > 50 μS/cm
Storage temperature : -10 to 50oC (-22 to 122 °F)
* The pH range at room temperature is 0 -14 pH, but at high temperatures the lifetime will be seriously shortened outside 2 - 12 pH range.

Model and Suffix codes

Yokogawa pH sensor FU20-05-T1-NPT