Noise control system for casting workshop

Abstract

The noise control system is arranged in a cutting area of the casting workshop, a conveying opening and an operation door are arranged in the cutting area, cutting tables are arranged on the two sides of the front end of the cutting area, a sound insulation cover is arranged in the cutting area, and a first opening and a second opening are formed in the positions, corresponding to the conveying opening and the operation door, of the sound insulation cover correspondingly. L-shaped enclosing walls are symmetrically arranged on the two sides of the middle of the acoustic hood, a half enclosing wall is arranged on the upper portion of the inner side of the front end of the cutting table, and an acoustic roof is arranged at the top ends of the L-shaped enclosing walls and the half enclosing wall. After the noise control system is adopted, the requirements of national occupational health can be met through noise level detection of six key control points on site.

Description

Technical Field

[0001] The present invention relates to the technical field of noise control, and particularly to a noise control system for a casting workshop. Background Art

[0002] Noise in the production process of the casting industry is one of the important occupational disease hazards. Its noise sources such as cutting and grinding are high-intensity noise sources. According to the requirements of the "Hygienic Standards for the Design of Industrial Enterprises" (GBZ 1-2010) and the "Code for Design of Noise Control in Industrial Enterprises" (GB 50087-2013), the equivalent continuous A-weighted sound level noise intensity in the workplace is required not to be greater than 85 dB(A) for 8 hours. Therefore, enterprises need to consider the protection against production noise hazards during the design of the production process, comprehensively analyze the production process, operation and maintenance, and noise reduction effects, and adopt effective technologies to control noise to achieve the purpose of occupational disease protection.

[0003] For the control of noise generated by the production process and equipment, control should first be carried out from the sound source. For example, workshops generating noise and non-noise operation workshops, high-noise workshops and low-noise workshops should be separated. On the premise of meeting the requirements of the process flow, high-noise equipment should be relatively concentrated, and corresponding noise insulation, sound absorption, noise elimination, vibration reduction and other control measures should be taken, so that the noise level to which noise-exposed workers are exposed meets the relevant requirements. If the requirements still cannot be met by adopting engineering control technical measures, the working and rest time should be reasonably designed according to the actual situation, and appropriate personal protection measures should be taken.

[0004] Currently, the commonly used noise control methods are as follows: ① In terms of process layout: Try to arrange high-noise sources indoors, and enclosed places can play a role in noise reduction; ② From the sound source: Select low-noise equipment or transform the structure to reduce the noise of the sound source; ③ From the propagation path: Take noise reduction measures such as isolation, noise elimination, sound absorption, and damping vibration reduction; ④ At the receiving point: Take measures such as labor protection earplugs and sound insulation doors and windows for residences. When actually controlling noise, several methods can also be combined, which generally can play a role in noise reduction.

[0005] However, for the cutting system in the casting workshop of the casting industry, since aluminum dust is generated during the cutting process and heat dissipation is required, it cannot be enclosed for noise reduction, and the role that ordinary noise reduction facilities can play is limited. Therefore, special layout of noise reduction facilities is required to achieve the purpose of noise reduction. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to provide a noise control system for a casting workshop in view of the deficiencies of the prior art, solve the problem of high noise in the existing casting workshop, and meet the requirements of national occupational health.

[0007] To achieve the above object, the present invention adopts the following technical solutions: A noise control system for a casting workshop, which is set in the cutting area of the casting workshop. The cutting area is equipped with a transmission port and an operation door. On both sides of the front end of the cutting area are cutting tables. A sound insulation cover is arranged in the cutting area. Openings 1 and 2 are respectively arranged at the corresponding positions of the sound insulation cover and the transmission port and the operation door. L-shaped enclosures are symmetrically arranged on both sides of the middle of the sound insulation cover. A half-enclosure is arranged on the upper part of the inner side of the front end of the cutting table. A sound insulation top is arranged at the top of the L-shaped enclosures and the half-enclosure.

[0008] Furthermore, the sound insulation top is of a semi-circular arc structure.

[0009] Furthermore, an acoustic lining is arranged inside the opening 1. The length of the acoustic lining is 13 - 15 times the width of the seam. A brush is arranged on the inner circumference of the acoustic lining.

[0010] Furthermore, the sound insulation cover, the L-shaped enclosures, the half-enclosure, and the sound insulation top are all made of composite sound insulation boards, which specifically include a support layer, a damping layer, a cavity, an acoustic absorption layer, and a protective layer.

[0011] Furthermore, a glass window is arranged above the opening 1. The glass window is double-layer acrylic glass. The upper part of the inner acrylic glass is inclined inward towards the sound source side.

[0012] Furthermore, the support layer is a 0.5 - 2 mm steel plate, the damping layer is a 1 - 3 mm asphalt coating, the cavity thickness is 0.5 - 1.5 mm, the acoustic absorption layer is 70 - 90 mm polyester fiber, and the protective layer is a 0.3 - 1 mm metal micro-perforated plate.

[0013] The beneficial effects of the present invention are: 1. The present invention discloses a noise control system for a casting workshop. Since the casting workshop is mainly used for aluminum cutting and casting, the maximum noise value measured on site can reach 104.12 dB(A), exceeding the national occupational health limit of 85 dB(A), and noise control is required. A sound insulation structure with good sealing can achieve a higher noise control effect. However, since aluminum dust will be generated during the cutting process, it cannot be made into a completely enclosed sound insulation area. On the one hand, a fully enclosed structure is not conducive to heat dissipation, and on the other hand, there is a risk of aluminum dust explosion. Moreover, due to the operation of the manipulator, openings must be set on site. To sum up, the present application adopts a noise control system with a semi-enclosure structure, which can not only ensure cutting safety and transportation, but also play a role in controlling noise and protecting against noise hazards.

[0014] 2. A sound insulation hood is set in the cutting area. Openings 1 and 2 are arranged at the corresponding positions of the sound insulation hood, the transfer port and the operation door respectively. Among them, a transfer pipeline is arranged inside the opening 1 for transporting materials. An acoustic lining is arranged inside the opening 1, and the length of the acoustic lining is 13 - 15 times the width of the seam. A brush is set at the contact position between the inner side of the acoustic lining and the transfer pipeline to avoid rigid contact between the acoustic lining and the conveyor belt, which may affect the sound insulation effect, and finally achieve the effect of sealing and noise reduction. A glass window is set at the upper part of the opening 1 as an observation window, which is a double-layer acrylic window. The upper part of the glass plate is inclined inward towards the sound source side to eliminate standing waves. On both sides of the middle part of the sound insulation hood, L-shaped enclosures are arranged at the cutting table position, a semi-enclosure is arranged at the upper part of the inner side of the front end of the cutting table, and a sound insulation top is arranged at the top of the cutting table. The sound insulation top is a semi-circular structure, which helps with heat dissipation from the upper part. In addition, the overall sound insulation hood, including the L-shaped enclosures, semi-enclosures, sound insulation top and other enclosure structures, all adopt modular sound insulation boards, specifically including a support layer, a damping layer, a cavity, an acoustic absorption layer and a protective panel. This combined structure, where the damping layer prevents resonance and coincidence effects of the sound insulation hood, and a cavity and an acoustic absorption layer are also arranged, has good sound absorption effect.

[0015] 3. After adopting the sound insulation hood of this application, the noise levels at 6 key control points on site meet the requirement of the on-site noise intensity value of 85 dB(A), indicating that the system arranged in this application can solve the noise problem in the casting workshop. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is the layout diagram of the casting workshop of the present invention; Figure 2 is the noise frequency spectrum diagram detected on site; Figure 3 is the layout diagram of the sound insulation hood in the casting workshop; Figure 4 is the structural schematic diagram of the sound insulation hood; Figure 5 is the structural schematic diagram of the acoustic lining inside the opening 1; Figure 6 is the structural schematic diagram of the sound insulation hood board; Figure 7 is the layout diagram of the noise control points in the casting workshop.

[0017] In the figure: 1 - transfer port, 2 - operation door, 3 - cutting table, 4 - sound insulation hood, 5 - opening 1, 6 - opening 2, 7 - L-shaped enclosure, 8 - semi-enclosure, 9 - sound insulation top, 10 - acoustic lining, 11 - brush, 12 - protective panel, 13 - support layer, 14 - damping layer, 15 - cavity, 16 - acoustic absorption layer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] The present invention will be further described below in conjunction with the drawings and specific embodiments. Embodiment 1

[0019] As shown Figure 1 in the figure, a noise control system for a casting workshop. The layout diagram of the casting workshop can be seen in Figure 1 . This casting workshop is mainly used for aluminum cutting and casting. In the cutting area, there are a transfer port 1 and an operation door 2 for on-site production operations. On both sides at the front end of the cutting area are cutting tables 3. Among them, the noise in the cutting area is very loud. Stop other equipment in the workshop and conduct on-site noise detection. The detection points are the inspection point ④ (cut-off point of the casting unit) in the right view of the cutting platform and the inspection point ③ (loading point of the casting unit) in the back view of the cutting platform. The results are shown in Table 1, and the on-site noise spectrogram can be seen in Figure 2 .

[0020] Table 1 On-site noise detection results of the cutting area

[0021] It can be seen from Table 1 that the maximum value of the noise detection in the casting area of this casting workshop is 104.12 dB(A), exceeding the national occupational health limit value of 85 dB(A). The multiple of the noise energy exceeding the national limit is about 84 times. There is a noise hazard and it is easy to cause occupational diseases. Therefore, it is necessary to control the noise. Figure 2 The on-site noise spectrum and analysis are as follows: 1) Low-frequency region - 250 Hz, the sound pressure level is between 36.74 dB(A) - 86.08 dB(A). The contribution of the low-frequency band at 250 Hz is relatively large, and the rest are relatively small; 2) Medium-frequency region 500 Hz - 2 kHz, the sound pressure level is between 80.19 dB(A) - 98.92 dB(A), and the medium-frequency band has a greater impact; 3) High-frequency region 2 kHz - 16 kHz, the sound pressure level is between 91.25 dB(A) - 62.94 dB(A). As the frequency increases in the high-frequency band, the sound pressure level decreases. Therefore, the main frequency of the noise in this workplace is in the 1000 Hz - 2000 Hz frequency band, that is, the medium-frequency band noise.

[0022] In addition, since this casting workshop is mainly used for heating and aluminum cutting, aluminum dust will be generated during the cutting process. Therefore, it cannot be made into a completely enclosed sound insulation area. A completely enclosed structure is not conducive to heat dissipation. In addition, there is a risk of aluminum dust explosion, and openings are also required for the operation of the manipulator. Therefore, considering from the perspectives of on-site production safety and sound insulation effect, the noise control system of this application adopts a sound insulation cover with a semi-enclosed structure, which is arranged in the cutting area. The key to sound insulation and noise reduction is to solve the problems of on-site noise reverberation, reflection, and superposition. The specific layout can be seen in Figure 3 .

[0023] Specifically: A sound insulation cover 4 is set in the cutting area. The structure of the sound insulation cover 4 is as shown in Figure 4 . Rubber gaskets are bonded at the contact points between the bottom of the sound insulation cover 4 and the ground for sealing; Openings 5 and 6 are respectively arranged at the corresponding positions of the sound insulation cover 4 and the transfer port 1 and the operation door 2.

[0024] There are 4 openings No. 1 - 5, each with an internal conveying pipeline for transporting materials. The size of the pipeline is 2m × 0.3m. To ensure noise protection at the openings No. 1 - 5, a sound-absorbing lining pipeline slightly larger than the conveying pipeline is used inside the openings No. 1 - 5 to enclose it. A dense brush is used for sealing at the contact area. Specifically, a sound-absorbing lining 10 is arranged inside the openings No. 1 - 5. The outer periphery of the sound-absorbing lining 10 matches the structure of the openings No. 1 - 5 and extends a certain length to both sides. See the cross-sectional view in Figure 5 , the length of the sound-absorbing lining 10 is 13 - 15 times the width of the seam. In this embodiment, it is 15 times. A brush 11 is arranged at the contact area between the inner side of the sound-absorbing lining 10 and the conveying pipeline. On the one hand, it avoids rigid contact between the sound-absorbing lining 10 and the conveying pipeline. On the other hand, it has a good sealing effect, thus achieving the effect of sealing and noise reduction.

[0025] A glass window 12 is arranged above the openings No. 1 - 5 as an observation window. The size is 2m × 0.5m. It is made of double-layer acrylic glass. The upper part of the inner acrylic glass is inclined inward towards the sound source side, with an inclination angle of 15 - 20°. In this embodiment, it is 15° to eliminate standing waves. The distance between the double-layer acrylic glasses, that is, the average thickness of the air layer, is 7 - 15cm. In this embodiment, the average thickness of the air layer is 7cm.

[0026] The noise at the corresponding position of the front side of the sound insulation enclosure 4 and the cutting table is relatively large. Therefore, a fence is arranged around the cutting table. Specifically, L-shaped enclosures 7 are symmetrically arranged on both sides in the middle of the sound insulation enclosure 4 (the rear side of the cutting table). A semi-enclosure 8 is arranged at the upper inner part of the front end of the cutting table 3, forming a diagonal structure with the L-shaped enclosures 7. A sound insulation top 9 is arranged at the top of the cutting table 3. The sound insulation top 9 is a semi-circular structure. This arrangement can make the noise of the cutting table diffract and attenuate in a small space that is not completely enclosed.

[0027] In addition, to reduce mid-frequency noise, the outer periphery and the inner side of the sound insulation enclosure 4, including structures such as the L-shaped enclosures 7, the semi-enclosures 8, and the sound insulation top 9, all adopt a combined sound insulation enclosure board, which is made by bonding and pressing multiple layers. See the structure in Figure 6 , specifically including a support layer 13, a damping layer 14, a cavity 15, a sound-absorbing layer 16, and a protective layer 12. Among them, the support layer is a 1mm steel plate, the thickness of the cavity is 1mm, the damping layer is a 2mm asphalt coating, the sound-absorbing layer is 80mm polyester fiber (polyester fiber sound-absorbing cotton), and the protective layer is a 0.5mm metal micro-perforated plate.

[0028] Specific installation method of the sound insulation enclosure: Columns are fixed on the outer sides of the four corners of the sound insulation enclosure 1 and fixed to the four corners of the sound insulation enclosure to enhance safety and stability. Rubber pads are bonded at the contact areas between the columns and the sound insulation enclosure, and between the sound insulation enclosure and the ground after bolt fixation to play a sealing role; in addition, the whole sound insulation enclosure is assembled with a combined sound insulation enclosure board and can be disassembled after use. Rubber pads are pasted at all the joints after installation for sealing.

[0029] After installing the sound insulation cover, the on-site noise was monitored again, as follows: The detection method was the same as that before installing the sound insulation cover. Other equipment in the workshop was shut down, and six positions were detected respectively, namely, the operator's console ① of the conveyor belt arranged outside the casting workshop, the inspection point ② beside the power distribution cabinet, the rear view inspection point ③ of the cutting platform, the right view inspection point ④ of the cutting platform, the inspection point ⑤ on the east side of the cooling area, and the inspection point ⑥ on the north side of the casting area. For the specific positions, please refer to Figure 7 , and the noise value at 1 m away from the sound insulation structure was used as the noise control point. The noise level of each control point was detected, and the results are shown in Table 2.

[0030] Table 2 Noise levels at each key control point

[0031]

[0032] After actual detection, the noise levels at the six key control points on site meet the requirement of the on-site noise intensity value of 85 dB(A). Compared with the detection results before installing the sound insulation cover, the sound insulation effect is excellent, and the system arranged in this application can solve the noise problem in the casting workshop.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Any other modifications or equivalent replacements made by those of ordinary skill in the art to the technical solutions of the present invention shall be covered by the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solutions of the present invention.

Claims

1. A casting workshop noise control system, arranged in a cutting area of ​​the casting workshop, wherein the cutting area is provided with a transmission port (1) and an operation door (2), and both sides of the front end of the cutting area are cutting tables (3), characterized in that: A soundproof enclosure (4) is arranged in the cutting area, and opening one (5) and opening two (6) are arranged at positions corresponding to the transmission port (1) and the operation door (2) of the soundproof enclosure (4), respectively; L-shaped walls (7) are symmetrically arranged on both sides of the middle of the soundproof enclosure (4); a half wall (8) is arranged on the upper inner side of the front end of the cutting table (3); and a soundproof top (9) is arranged at the top of the L-shaped wall (7) and the half wall (8).

2. A casting workshop noise control system according to claim 1, characterized in that: The sound insulation roof (9) is a semi-arc structure.

3. A casting workshop noise control system according to claim 1, characterized in that: A sound absorbing lining (10) is arranged on the inner side of the opening 1 (5); the length of the sound absorbing lining (10) is 13-15 times the width of the slit; and a brush (11) is arranged on the inner periphery of the sound absorbing lining (10).

4. A casting workshop noise control system according to claim 1, characterized in that: The sound insulation cover (4), L-shaped enclosure (7), half enclosure (8), and sound insulation roof (9) all adopt a combined sound insulation board, which specifically includes a supporting layer (13), a damping layer (14), a cavity (15), a sound absorption layer (16), and a protective layer (12).

5. A casting workshop noise control system according to claim 1, characterized in that: A glass window (12) is arranged at the upper part of the opening 1 (5); the glass window (12) is a double-layer acrylic glass, and the upper part of the inner acrylic glass is arranged to be inclined inwards towards the source of life.

6. A casting workshop noise control system according to claim 4, characterized in that: The support layer (13) is a 0.5-2 mm steel plate, the damping layer (14) is a 1-3 mm asphalt coating, the cavity (15) has a thickness of 0.5-1.5 mm, the sound absorbing layer (16) is a 70-90 mm polyester fiber, and the surface layer (12) is a 0.3-1 mm metal micro-perforated plate.

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