Senior supply pump noise isolation Control Project

Level of noise isolation for pump control project Bo Chen 1 Introduction Shenyang broadcast a building five-star international hotel. Its water pumping station on the 20th floor, the upper and lower floors and residential Scriptorium by pump vibration and noise, noise A sound level reaches 45dB, 5-star than the national standard hotel room the night noise ≤30 dB (A) standard. Using pumps is a German company producing vertical section pumps. Model CR32-5-2, power 11kw, head 69.7-90.2 m, flow rate is 30m3 / h, operating speed of 2924rpm. 2 uses a vibration isolation measures began to take a less than ideal control conventional requirements, treatment room downstairs on the 19th floor noise 35 dB (A), 21 floors noise is 33dB (A). Analysis of the main reasons the pump on the floor, having a vibration amplification effect, the conventional vibration isolation is difficult to achieve the desired effect. The other is the uneven distribution of basis weight of steel, the pivot bearing different in size, if you select the same frequency of the elastic element, resulting in the natural frequency of each point is not the same, the isolation is not ideal, reach a unified isolation requirements. To further reduce noise, vibration control have taken the unusual measure: select a different combination of rigidity damping spring, and has taken a combination of lateral and vertical vibration isolation combination. Isolation means total vertical stiffness 13.6 N / mm, free height 70mm, compression about 30 mm long. Tests show that taking a combination of different directions, vibration isolation effect achieved is not the same as shown in Table 1. After treatment, 21 floors lower noise, reduced to 27 dB (A) for the background values. 3 using secondary isolation from the calculation shows that, when using the first isolator, isolation efficiency of 98.6% when using secondary isolator, isolation efficiency increases with the mass ratio of increasing the maximum isolation efficiency. When the mass ratio is greater than 0.47, isolation efficiency ratio decreased. You can not increase. When the mass ratio of about 0.03, the system resonance occurs, the system does not isolation. The results in Table 2 rigidity than the quality of the natural frequency of vibration than the noise reduction coefficient isolation efficiency / dB 1.00 0.03 151.87 16.12275 -1512.28 0 1.00 0.12 74.86 0.00218 99.78 39.9 1.25 0.35 46.84 0.00076 99.92 46.8 1.50 0.47 42.92 0.00067 99.93 47.6 4 Conclusion using two second vibration isolation level for the pump is better than a vibration isolation, but be careful to avoid system resonance.