1 Scope
This process standard is applicable to the production and installation of resistance, resistance, and resonance mufflers.
2. Construction preparation
2.1 Material requirements and main equipment:
2.1.1 All types of plates and steel sections should have factory certificates or quality appraisal documents.
2.1.2 In addition to the aforementioned proof documents, a visual inspection should also be conducted. The surface of the board should be flat, with uniform thickness, no protrusions or obvious pressure marks, no cracks, delamination, pitting, or corrosion. Steel sections should be equal and free of defects such as cracks, scratches, and pitting that affect quality.
2.1.3 Sound absorbing materials should be selected strictly according to design requirements and meet the requirements of fire prevention, moisture resistance, and corrosion resistance.
2.1.4 Other materials shall not reduce the strength of the finished product or affect its effectiveness due to defects.
2.1.5 Longmen shearing machine, vibration curve shearing machine, manual electric shearing machine, chamfering machine, biting machine, square analysis machine, biting compaction machine, sewing machine, steel cutting machine, punching machine, bench drill, hand drill, hydraulic rivet pliers, electric rivet gun, air compressor, paint spray gun, steel ruler, angle ruler, protractor, scratch, scratch needle, punch, hammer, wooden hammer, clapper, pulley, chain block, rope.
2.2 Operating conditions:
2.2.1 There should be spacious, bright, flat, and clean factory buildings.
2.2.2 The work site should have machinery, facilities, power sources, safety protection devices, and fire-fighting equipment that meet the requirements of the processing technology.
2.2.3 The muffler should be made according to the requirements of the design drawings and standard drawings, and there should be written quality, technical, and safety instructions from the construction personnel.
2.2.4 The materials used in the production of mufflers should meet the requirements of fire prevention, corrosion prevention, moisture prevention, and hygiene.
3 Operation process
3.1 Process flow:
3.2 Muffler. The processing of various metal plates should adopt mechanical processing, such as cutting, folding squares, folding edges, biting, etc., to achieve one-time molding and reduce manual operation. During the construction of galvanized steel plates, attention should be paid to not damaging the galvanized layer and to biting or riveting as much as possible.
3.3 The muffler frame should be firm and the shell should not leak air. The production of muffler outer tube, inner tube, cover plate, partition plate, flange production, and riveting refer to section 4.1.
3.4 The internal dimensions of the resistance muffler (Figure 4-28) cannot be changed arbitrarily during the processing. The resistance muffler (Figure 4-29) is made of wood reinforcement and wooden frame (if the design requires a metal structure, it should be processed according to the design requirements), filled with ultra-fine glass wool and other sound-absorbing materials, and covered with glass cloth and other covering materials. When filling sound-absorbing materials, they should be evenly laid according to the design weight, thickness, and other requirements, and the covering layer should not be damaged. When installing the nail sound absorber, paint foam nails shall be used for the part in contact with the air flow, and shoe nails shall be used for binding the rest. When nailing, add a layer of gasket on the nail to reduce damage. For large sound absorbers, appropriate support baffles can be installed inside the cavity to prevent the sound-absorbing material from sinking due to the installation or movement of the muffler. 3.5 Resistance muffler Figure 4-30 adopts a sudden change in pipeline cross-section to achieve noise reduction effect. During the processing, the size of the expansion chamber must not be changed arbitrarily.
3.6 The resonant muffler (Figure 4-31) should be processed according to the design requirements. The dimensions of key components cannot be changed arbitrarily. The aperture and perforation rate of the perforated plate should meet the design requirements. After punching (drilling) holes in perforated plates, the burrs on the holes should be smoothed out. The size of the partition of the resonant cavity should be correct, and the connection between the partition and the wall panel should be tightly connected.
When assembling the 3.7 impedance composite muffler (Figure 4-32), the made muffler should be first nailed into a muffler group with round nails, and the transverse partition and inner pipe should be riveted in sections with rivets. Then, the inner pipe and muffler group should be fixed in each section with half round head wood screws. Finally, the outer pipe and transverse partition, as well as the cover plates at both ends of the outer pipe and muffler, should be fixed with semi countersunk head self tapping screws. The cover plates and inner pipes should be fixed with flanges at both ends of the riveting.
The sound-absorbing materials for the lining of the 3.8 sound-absorbing air duct, sound-absorbing static pressure box, and sound-absorbing elbow should be evenly adhered and not fall off. The gaps should be dense, and the surface should be smooth and even.
The sound-absorbing material covering layer inside the muffler should not be damaged, and when overlapping, it should be downwind with no burrs on the interface. The direct upwind cloth inside the muffler should be protected.
When the side length of the muffler bend plane is greater than 800mm, a guide and sound absorbing sheet should be added. The surface of the diversion sound-absorbing sheet should be smooth, with uniform arcs, and tightly and firmly connected to the bent pipe. Do not loosen.
3.11 The soundproof louvers should have a sturdy frame, uniform blade spacing, and sound absorption direction that meets the design requirements.
3.12 The surface of the metal components inside and outside the muffler should be coated with red lead anti rust paint (high-quality galvanized sheets should not be coated with anti rust paint). Before brushing, the metal surface should be treated as needed to remove rust, grease, and other debris. When painting, there should be no omissions, bubbles, or exposed substrates.
The assembled finished product should be inspected according to the design documents and construction acceptance specifications, and can only be shipped after meeting the requirements.
3.14 Mufflers, silencing elbows, etc. should be separately supported and suspended to prevent the air ducts from bearing their weight.
3.15 The hanger should be selected based on the model, specifications, and building structure of the muffler, and according to the standards or design drawings. Before installing the muffler, check whether the fixed parts such as brackets and hangers are in the correct position, and whether the embedded parts or expansion bolts are installed firmly and reliably. Supports and hangers must ensure load capacity.
3.16 The distance between the screw holes of the suspension rod on the muffler bracket and hanger support iron should be slightly wider than that of the muffler by 40-50mm. In order to facilitate adjusting the elevation, the end of the suspension rod can have 50-60mm threads for leveling and correction. It can also be leveled and corrected by adding pads on the support iron.
The installation direction of the muffler must be correct, and the flange connection with the air duct or pipe fittings should be tight and firm.
3.18 When the air conditioning system maintains a constant temperature and high requirements are met, the muffler casing should be insulated from the air duct.
After the installation of the 3.19 muffler, it can be inspected by pulling or hanging wires. If it does not meet the requirements, it should be repaired.
After the muffler is installed in place, management should be strengthened and protective measures should be taken. It is strictly prohibited to fix other brackets on the muffler flange and bracket.
4 Quality Standards
4.1 Guarantee Project:
4.1.1 The model and size of the muffler must meet the design requirements and indicate the direction of airflow.
Inspection method: Measuring with a ruler and observing for inspection.
4.1.2 The muffler frame must be firm, the size of the resonant cavity partition must be correct, the partition must be tightly integrated with the wall panel, and the shell must be tight.
Inspection method: Hand cranking and observation inspection.
4.1.3 Single installation of sound-absorbing panels, the fixed end must be firm and the spacing between panels must be uniform.
Inspection method: Hand cranking and observation inspection.
4.1.4 The installation direction of the muffler must be correct, and separate supports and hangers must be set up.
Inspection method: Observe and inspect.
4.2 Basic Projects:
4.2.1 The laying of sound-absorbing materials should be firmly and smoothly pasted; Bulk materials are evenly filled without sinking.
Inspection method: Observe and inspect.
4.2.2 The coverage of the sound-absorbing material should be spliced in the downstream direction, neatly spliced, and undamaged; The perforated plate has no burrs and the hole spacing is evenly arranged.
Inspection method: Observe and inspect.
5. Finished product protection
5.1 The finished muffler should be placed on a flat and water free indoor site, with a gasket at the bottom and necessary waterproof measures taken.
5.2 Finished products should be numbered according to specifications and models. Properly store and prevent erosion from rain, snow, soil, dust, and moisture.
5.3 Mufflers should be placed gently during loading, unloading, transportation, and installation to avoid damaging the finished product.
Before installation, the muffler should be checked and the filled sound-absorbing material should not sink significantly. Repair quality defects.
After the installation of the muffler, if the work phase is suspended, the port should be tightly wrapped to prevent damage or entry of debris.
6. Attention should be paid to quality issues.
6.1 The covering material of the muffler is prone to damage, exposing or peeling off the sound-absorbing material, which affects its function. During the production process, a gasket should be added. If damage to the covering material is found, it should be repaired or replaced promptly according to the situation.
6.2 Silencer installation for noise reduction.
