What is the difference for ultrasonic cleaning?

Why does Getinge use two different types of piezoelectric transducers in its Ultra Clean Systems ultrasonic cleaning machines? Bonded ceramic and titanium rod transducers (TRTs) each have advantages and disadvantages. The one we choose is driven by the needs of the user and the design of the ultrasonic cleaner.

Bonded transducers are made of piezoelectric ceramic materials that are bonded to metal electrodes and are relatively simple to manufacture. They are compact and more affordable, making them ideal for our smaller countertop model, the 1100. While they deliver precise cavitational energy, their placement can result in cold spots within the basin with little to no cavitation.

Titanium is a strong, lightweight, and corrosion-resistant metal, making TRTs more durable and suitable for use in harsh environments. Immersion in the basin allows for more efficient cleaning; however, the TRT requires extra clearance around the rod, which means a bigger basin, eliminating the compact size.

Here are some important considerations:

Durability

Titanium rods are stronger and more durable than bonded ceramic transducers, which are more delicate and can delaminate or crack over time. Titanium is a lightweight metal that can withstand high temperatures and harsh chemicals. Thus, titanium rods are less likely to fail and usually last longer, meaning a longer lifespan for the ultrasonic cleaner.

Size

Since bonded transducers are compact and are attached to the exterior of the tank, the tank (and the machine) can be smaller. The TRT, on the other hand, requires extra space inside the tank, making the entire machine larger, taking up more floor or counter space.

Efficiency

Titanium rods convert electrical energy into ultrasonic vibrations more efficiently than bonded transducers. With the TRT submerged in the tank, rather than being bonded to the outside of the tank, the energy is conveyed directly to the liquid medium (typically water with an enzymatic detergent), reducing the cleaning time needed and requiring less power to generate the same level of cleaning action. This results in lower energy consumption and operating costs. Bonded transducers must transport their energy through the metal of the basin, resulting in some energy loss.

Cost

Initial costs for bonded ceramic transducers are lower than for TRT technology. The cost of titanium is relatively high compared to the materials used in the bonded ceramic transducers.

Consistency and Flexibility

With their radial cavitation along the length of the rod, TRTs provide more even and consistent cleaning performance than bonded transducers, which can vary in their output due to differences in bonding quality and positioning. Bonded transducers offer greater flexibility as their placement can vary based on the instruments to be cleaned. They offer a more precise, targeted cavitation, although their placement also can result in cold spots in the tank. TRTs have limited flexibility in positioning.

Although TRTs are more durable and tend to last longer, when they fail, the entire rod fails and there is no cavitation until it is replaced. Bonded transducers are electrically connected in a series, so if one transducer fails, the rest will continue working. This results in a cold spot in that area of the basin, but allows some cleaning to continue.

Maintenance

Once the transducers fail, TRTs are easy to remove and replace. The piezoelectric crystals are housed inside the rod and can be replaced, and the entire rod can be swapped out onsite. Even if only one bonded transducer fails, the entire series must be removed to replace the failed one. This work must be done offsite, as once all the transducers are working again, the tank surface must be prepped and the series must be rebonded to the tank.

As you can see, there are many considerations when determining the best type of transducer for an ultrasonic cleaner. Ultra Clean Systems uses both technologies in its ultrasonic washers (and produces the only ultrasonic surgical instrument cleaners that use TRT technology). Just as it is for us, your particular needs will determine which technology works best and is most cost effective for you.