The SKF TKST 21 Stethoscope is a high quality hand-held instrument that monitors noise in bearings, machines and components. 

“The ability to ‘listen’ to rotating equipment and machine components, detect errors and reliably identify the possible cause of the noise at an early stage, allows for preventative maintenance before costly failures can occur,” says Eddie Martens, Business Development Manager: Maintenance Products at SKF South Africa.

The device can be applied in a wide variety of industry sectors including power plants, automotive, recycling, materials handling, food & beverage and paper mills.

The TKST 21 consists of the hand-held instrument, a headset with an adjustable ten-level volume control, two probes of differing lengths (70mm and 300mm) for easy access to hard-to-reach areas, two AA Alkaline batteries and an instruction manual. Everything is neatly packed inside a sturdy carry case for easy portability, handling and storage.

The Stethoscope is able to pick up noise in a range of components such as bearing housings, gears, valves, vents and pumps. The device captures the most common problematic bearing noises such as damaged bearings and balls, damaged inner and outer rings as well as ash contamination and cavitation; valve chatter, tappet noise and piston slap can also be monitored.

Once the acoustic data (noise) is captured by the probe, the recorded audio is transmitted to a sensor, converted into an electrical signal, processed and amplified, and then fed to the headset or a recorder. Operators have the option of listening in live mode through the high quality, noise cancelling ear defender approved headset or recording the sounds for replay and comparison with the live sound. “The excellent sound quality enables the operator to identify the sound of problematic parts reliably, clearly and accurately, even in extremely noisy environments,” adds Martens.

The device is lightweight (1670g) and ergonomically designed for convenient and comfortable one-hand operation. A large, backlit colour display, a unique feature for this type of device, facilitates viewing. 

The user-friendly settings menu allows for easy navigation through a host of functions such as changing the display brightness, switching the volume limiter OFF, etc. The Stethoscope can even be muted if required. The instrument operates in a frequency range of 30 Hz3 to 15 kHz and will perform optimally in temperature extremes of -10 to +45 °C. The battery lifetime will provide a minimum of ten hours of operation during continuous use.