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Ridge structure perforated pipe noise elimination unit for reactive muffler

A technology of resistant noise reduction and noise reduction units, which is applied in the direction of noise reduction devices, engine components, machines/engines, etc., can solve problems such as the disordered flow of air flow in the pipe section, affect the noise reduction performance of the muffler, and high air flow regeneration noise, etc., to achieve utilization The effect of increasing the frequency, increasing the value, and improving the low-frequency noise reduction performance

Active Publication Date: 2015-03-04
SHANDONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] It is known from manufacturers of resistant mufflers for construction machinery that at present, the perforated pipe muffler unit generally adopts the uniform perforation method in this industry, and those skilled in the art also generally agree that the perforated sections are evenly distributed on the entire pipe section and have as many perforations as possible. method, because this method can give full play to the advantages of the perforated pipe's low-frequency noise reduction performance and small pressure loss, but this method will cause the airflow inside the pipe section to flow in disorder and the speed fluctuates violently, resulting in high airflow regeneration noise and affecting the muffler's noise reduction In addition, due to technical prejudice, those skilled in the art will rarely consider the impact of the position of the perforation and the structure of the inner wall of the muffler on the sound attenuation effect

Method used

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  • Ridge structure perforated pipe noise elimination unit for reactive muffler
  • Ridge structure perforated pipe noise elimination unit for reactive muffler
  • Ridge structure perforated pipe noise elimination unit for reactive muffler

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] Aiming at the perforated pipe muffler unit of the resistant muffler used in construction machinery, it is applied to the complex resistant muffler, as shown in Fig. Trachea 3, outlet pipe 4, chamber Ⅰ5, chamber Ⅱ6, chamber Ⅲ7, the airflow enters chamber Ⅰ5 from the inlet pipe 3, then flows through the ridge structure perforated pipe 1 and enters chamber Ⅱ6, and then the airflow enters the perforation in the second and third chambers Pipe 2 reaches chamber III7 and is discharged into the atmosphere through outlet pipe 4.

[0042] The ridge structure used in this example is a trapezoidal ridge structure and protrudes outward on the inner wall of the perforated tube, and the lower bottom of the trapezoidal ridged structure is seamlessly attached to the inner wall of the perforated tube. See attached drawings 7 (a-b) for specific dimensions It is: including the perforated tube body 8, the trapezoidal ridge structure 2, and the perforated section 3, wherein the length of the...

Embodiment 2

[0045] For the perforated pipe muffler unit of the resistant muffler used in construction machinery, it is applied to the complex resistant muffler, as shown in Fig. 3. Outlet pipe 4, chamber Ⅰ5, chamber Ⅱ6, chamber Ⅲ7, the air flow enters 5 chamber Ⅰ from 3 inlet pipe, then flows through 1 ridge structure perforated pipe into 6 chamber Ⅱ, and then the air flow enters 223 The cavity perforated pipe reaches the 7th chamber III, and is exhausted to the atmosphere through the 4th outlet pipe.

[0046] The perforated tube with ridge structure used in this example has a trapezoidal ridge structure and is recessed on the inner wall of the perforated tube, see Figure 6 (a-b). 3. The length of the perforated pipe is 219mm, the inner diameter is 30mm, the trapezoidal ridge structure is an isosceles trapezoid with a height of 1mm, an upper bottom of 1mm and a lower bottom of 2mm, and is arranged on the inner wall for 20 turns along a helix with a pitch of 5mm. The diameter of the perfo...

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Abstract

The invention discloses a ridge structure perforated pipe noise elimination unit for a reactive muffler. The ridge structure perforated pipe noise elimination unit comprises a perforated pipe and is characterized in that the segment, arranged in the perforated pipe in the air flow transmission direction, of the perforated pipe in the air flow outlet direction is provided with perforated holes used for improving the low-frequency muffling performance of the perforated pipe; a ridge structure with the resistance reduction characteristics is arranged on the inner wall, in the air flow inlet direction, of the perforated pipe; when the air flow flows the perforated pipe, the air flow is carded by the ridge structure and then flows out of the perforated hole segment. The resistance reduction characteristics of the ridge structure are utilized by the ridge structure perforated pipe noise elimination unit for carding the air flow; and the aerodynamics performance of the airflow is improved. The evenly-distributed perforated holes in the full segment of a common perforated pipe are changed into evenly-distributed perforated holes in the rear portion of the pipe segment; and the low-frequency noise elimination performance of the perforated pipe is improved.

Description

technical field [0001] The invention relates to a novel perforated tube muffler unit structure for a resistant muffler, in particular to a perforated tube structure for a resistant muffler used in engineering machinery. Background technique [0002] The resistant muffler is the main way to control the exhaust noise of construction machinery, and the perforated pipe is one of the indispensable muffler units in the resistant muffler. It is known from the actually measured 1 / 3 octave spectrum of the exhaust noise of construction machinery , the frequency bands that contribute a lot to the exhaust noise are mainly concentrated in the low frequency band, so the control of low frequency noise is an effective way to reduce exhaust noise. Since the perforated pipe structure has its corresponding resonance frequency, it is preferable to use it near the resonance frequency. Ideal noise reduction effect, so rational design of its resonance frequency, so that it can effectively reduce l...

Claims

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Application Information

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IPC IPC(8): F01N13/00F01N1/08
Inventor 周以齐李瑞米永振白儒
Owner SHANDONG UNIV
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