Remote Probes

To complement its range of ultrasonic thickness gauges, Cygnus Instruments offer a range of ultrasonic probes. The performance of any ultrasonic thickness gauge relies heavily on the quality of the probe and its suitability to the material being measured. Therefore selecting the right probe is vital.

All Cygnus probes are constructed from stainless steel and incorporate a replaceable wear membrane to protect the probe face ensuring years of reliable, accurate service.


Guidelines for Probe Frequency Selection

The probe frequency will be determined by the minimum thickness you need to measure, however the lower the probe frequency the more effective the ultrasound will be at penetrating coatings and corrosion. The 2.25 MHz 13mm probe is recommended for the majority of applications as it performs the best on corroded metal and through thick coatings.

FrequencyFace SizeFace ColourRange In SteelTypical Applications
5.0 MHz6 mm (1/4”)Black1 to 50 mmSmall diameter pipes and boiler tubes/heat exchangers
5.0 MHz13 mm (1/2")Black1 to 50 mmMeasuring wall thickness down to 1mm
3.5 MHz13 mm (1/2")Orange2 to 150 mmMeasuring wall thickness down to 2mm with corrosion through coatings
2.25 MHz13 mm (1/2")Red3 to 250 mmStandard probe supplied, best for all round measurement of wall thickness with corrosion through coatings.
2.25 MHz19 mm (3/4")Red3 to 250 mmLarge flat plates with heavy corrosion and/or through thick coatings.

Probe Membranes

All Cygnus probes have a protective membrane fitted in front of the probe face to protect it from damage during use on rough corroded surfaces. A thin film of membrane couplant sits between the membrane and the probe face to allow the ultrasound to pass through. The membrane also helps the probe face “mould” to uneven corroded surfaces aiding measurement.

The performance of the probe depends on the condition of the membrane and how well it has been fitted. Cygnus recommends membranes are replaced frequently as a precaution or at the first sign of any scoring, tearing or damage.

Membranes are available in two materials, the standard Polyurethane membrane is suitable for surface temperatures up to 75°C (167°F), the Teflon membrane is suitable for surface temperatures up to 150°C (302°F) with a maximum contact time of 5 seconds.

Standard Polyurethane (75°C) Pack of 20

Order CodeProbe Size
001-37026mm Probe
001-370113mm Probe
001-370019mm Probe

Teflon (150°C) Pack of 10

Order CodeProbe Size
001-48736mm Probe
001-487413mm Probe
001-487519mm Probe


Remote Probes

Remote Probes for use with Cygnus 2, Cygnus 3 & Cygnus 4 Gauges. Probes are fitted with a BNC connector as standard but can be supplied with a Lemo-00 connector upon special request.

All Remote Probes are supplied with a 1.35 meter probe cable with a choice of connector to suit the model of thickness gauge.

Note. For Underwater, Intrinsically Safe & Heavy Duty gauges specific remote probes are available and are detailed on separate Data Sheets.


Order CodeFrequencyFace SizeProbe ConnectorCable ConnectorCable Connects to
004-93615.0 MHz13mmBNCLemo 1Mk4 Cygnus 2, 3 & 4 Gauges
004-93133.5 MHz13mmBNCLemo 1Mk4 Cygnus 2, 3 & 4 Gauges
004-93102.25 MHz13mmBNCLemo 1Mk4 Cygnus 2, 3 & 4 Gauges
004-93112.25 MHz19mmBNCLemo 1Mk4 Cygnus 2, 3 & 4 Gauges
004-93145.0 MHz6mmLemo 00Lemo 1Mk4 Cygnus 2, 3 & 4 Gauges
004-93155.0 Mhz13mmLemo 00Lemo 1Mk4 Cygnus 2, 3 & 4 Gauges
004-93123.5 MHz13mmLemo 00Lemo 1Mk4 Cygnus 2, 3 & 4 Gauges
004-93012.25 MHz13mmLemo 00Lemo1Mk4 Cygnus 2, 3 & 4 Gauges