Pleasant Sound with Lower Vibration Levels

Using our patented, state-of-the art SERENADETM Technology, Shimadzu has designed and developed a new line of gear pumps called SERENADETM Gear Pumps.

  1. Expertise in the production of low noise and low vibration gear pumps
  2. Maintaining Shimadzu’s standards of highly durable gear pumps, which differentiates us from many competitors
  3. Implementation of special engineering processes during production
  4. Meticulous inspection upon completion to double-check for quality and reliability

SERENADETM Technologies

Gear Pump With Pleasant Comfortable Sound

“SERENADETM” is state-of-the-art technology for low noise / low vibration gear pumps that Shimadzu has developed. “SERENADETM Technologies” is a comprehensive concept that is achieved from these different aspects ;

  1. Advanced proficiency in low noise and low vibration development.
  2. Production engineering methods to achieve simultaneously low noise, low vibration and high durability throughout the mass production process.
  3. Inspection accuracy to provide stable and high-quality products.

SERENADETM Gear Pump Series

1. SMG Series sound

Discharge flow pulsation of a gear pump is one of the known causes of noise and vibration. The SMG Series achieves low noise and vibration by reducing the discharge flow pulsation; making the backlash (the gap between the tooth surfaces of a combination of gears) as close as possible to zero.

2. SRP Series NEW sound

In addition to the low noise and vibration of the SMG series, the SRP series is able to provide a pleasant and comfortable sound for operators. Shimadzu focused on the reduction in piping vibration at the suction side through advanced acoustic analysis.

Reducing the vibration of piping at suction side

The graph on the left compares the vibration of the suction piping between SMG 300 and SRP 300. SRP 300 reduced the vibration of the suction piping at all rotational speeds.

What makes it a comfortable sound?

The evaluation on the test bench with dBA does not necessarily correspond to the actual sound level of the vehicle. By adopting a tone quality evaluation index “Loudness” instead of dBA, Shimadzu discovered what makes sound comfortable. What is important is the quality of actual sound heard by the operator, not the sound created by the gear pump itself.

What is really “Loudness”?

“Loudness” is a sound quality evaluation index based on the human sense.

1. Equal-Loundness Contour

“ Sound that is easily heard”

The graph on the left shows which frequencies are more audible in the human ear. The lower the Sound Pressure Level, the easier it is to hear. The most audible range is between 3000 and 4000 Hz.

2. Spectrum Masking

“Masking effect”

When sound “A“ of a certain frequency is heard by a human ear, and if a sound “B” that is close to the frequency of sound “A” is to be heard, the sound “B” is masked by the sound “A” and becomes less audible. This phenomena is called “Masking effect".

3. 1/3 Octave Bandwidth and Critical Bandwidth

“Distinguishing the sound”

In terms of loudness, the human ear can hear sounds only 1/3 octave wide. However, as shown on the left graph, the resolution is roughly 1/3 an octave at 500 Hz or less.

Sound comparison of SMG and SRP by operator ears

The graph on the right shows the Loudness at each frequency. SRP 300 has a lower Loudness than SMG 300.

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