June 6, 2018

Transducers

Transducer classification

Shipsonic™ has different transducer classifications; water-resistant IP63 and water-proof IP67.

Our different transducers, often used in combination,  are:

  •   50 Watt 17 kHz, different housings available
  •   50 Watt 40 kHz, IP67
  •   80 Watt 23 kHz, different housings available
  • 100 Watt 28 kHz, IP63
  • 100 Watt 28 kHz, IP67
  • 120 Watt 20 kHz, IP67

Transducer characteristics

Correct ultrasonic frequency

Scope-reading of frequency response test

We use heavy, low frequency transducers for 2 reasons:

– the lower ultrasonic frequencies are more effective

– the resonance frequency of a transducer goes up about 16 kHz

once it is installed on an object like a box-cooler (thus a 20 kHz

transducer will make your box cooler resonate with approximately

20+16=36kHz)

Our design features a standalone software module for each transducer, looping constantly through all frequencies from 20 to 60 kHZ. This enables us to ensure that each transducer/object combination always receives pulses in its optimum range.

 

Sufficient ultrasonic energy

Measuring ultrasonic energy attenuation on 10 mm steel

We are the only ones working with transducers of up to 120 Watt. The equation is simple, heavier transducers give more ultrasonic sound. More sound means less fouling. A 50 Watt transducer may be enough for a polyester sailing-boat, but if you want to protect a sea-chest made of 12 mm steel, 50 Watt is not going to be enough. Our HDs series is explicitly designed for ocean going vessels, hence the heavy, low frequency transducers.

Correct transducer location

Correct transducer location is an acoustical problem, and acoustical problems are notoriously complex.

Prototype of the ultrasonic signal strength tester we use to optimize transducer location

Prototype of the Shipsonic ultrasonic signal strength tester

Magnetic transducer for sound pressure measurements

Magnetic-test-transducer

To address it, Shipsonic has developed an ultrasonic signal strength measuring device. This signal tester uses a contact microphone to measure ultrasonic energy levels in the steel of the object to be protected. This way we can compare tester readings of different transducer locations and thus optimize transducer location. Our most important agents have a signal strength tester.

 

 

Optimal transducer design

Various transducer housings of 100 and 120 Watt models

We intentionally chose a PVC or POM housing, while this is not common in shipping. However, metal housings have too much mass compared to the mass of the transducer itself. These housings, therefore, absorb more energy, sometimes resulting in the housing cracking up. The mass of the metal housing also affects the resonant frequency of the transducer. The PVC or POM housing of the transducer is not a way of cost-saving, but a conscious technical design choice. Within the PVC or POM housing, the resonance element of the transducer can vibrate completely independently.

 

Installation

Comparing different transducer housings and different ways of fixation

Different transducer-housing and -fixation testing

All our transducers are directly glued on the object to be protected. For the 100 and 120 Watt models, the contact surface of the transducer is glued directly to the object to be protected, so no intermediate steel or artificial part of the housing gets in the way. For these models we also offer installation adaptors. These consist of an aluminium disk with a threaded rod. The disk has the same diameter as the foot of the transducer, the rod the same thread as the threaded hole in the transducer. These adaptors can be machined in the same curve as e.g. piping or a bucket strainer on which the transducer is to be installed.

Consult Shipsonic or one of it’s agents for help with the optimal configuration of your system.

Available transducer models

50 Watt 17 kHz, different housings available

Transducer 50Watt, 17kHz

This model has recently been taken up in our range. It was chosen for its exceptionally low response frequency; of only 17 kHz. Even given the usual frequency step that results from installation (see above: ‘correct ultrasonic frequency’), the resulting frequency is still very low. Which means: very effective!

 

 

 

 

50 Watt 40 kHz, IP67

50 Watt and 100 Watt transducer

50Watt, 40kHz, IP67 and 100Watt, 28kHz, IP67 transducer models

We use the 50Watt; 40kHz  transducers especially for the off shore sector involving ROVs. These ROVs use ultrasonic frequencies (for positioning) too near to the frequency of our 100 or 120 Watt models.

 

 

 

 

80 Watt 23 kHz, different housings available

Transducer 80Watt, 23kHZ, 4 piezos

At first sight, this transducer seems not very different form other ones in our range. Power of 80 Watt is not exceptionally high, and response frequency of 23kHz is not exceptionally low. However, the trick is in the size. The other low response frequency transducers in our range, have a foot-diameter of 78 mm. While this model has a foot-diameter of only 45 mm. That makes this model especially apt for installation on box-coolers.

 

 

 

100 Watt 28 kHz, IP63

The 100Watt, 28kHz is our most used model. Its vibrating surface is directly glued to the object to be protected. This model can be used with the aluminium installation adaptor. The adaptor can be machined in the same curve as e.g. piping or a bucket strainer on which the transducer is to be installed.

 

 

 

 

100 Watt 28 kHz, IP67

100 Watt, 28 kHz, IP67, POM housing, stainless steel foot

This is the waterproof version of the 100Watt, 28kHz IP63 version. Recommended when installed on sea-chests or hulls where there is cooling liquid, water, oil etc sloshing around. It cannot be used with the adaptor.

 

 

 

 

120 Watt 20 kHz, IP67

transducer, 120Watt, 20kHz, IP67

This is quickly becoming our new standard. A heavy hitter, 120 Watt!. Very good for application on the lid of the box-cooler, on the sea-chest or on the hull. Its vibrating surface is directly glued to the object to be protected. This model can also be used with an aluminium installation adaptor (with a bigger diameter than the 100Watter). The adaptor can be machined in the same curve as e.g. piping or a bucket strainer on which the transducer is to be installed.

 

 

Recommended glues

Glue used to install the transducers should harden completely, like glass. Glues that maintain some elasticity, are not suited. The elasticity dampens the ultrasonic vibration.

 

For gluing the transducer itself we recommend Loctite 3090.

 

 

For protecting the glue-seem against liquids (cooling liquid, oil that might slosh around) we recommend you apply Tec7 around the seem after installation of the transducer.

 

 

Loctite 518 can be used between the surfaces of the transducer and the adaptor.

 

 

For all transducer installation manuals, for transducer localization manuals and for glue material safety and technical data sheets, please go to our download area.

To learn more about our range of control units, go here

 

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