(1) The box is a square box with flat top and flat steel plate at the bottom for easy dragging;
Low noise generator set
(2) An air inlet sound box (including rat proof net) at the rear of the box allows air to enter and exit freely during the operation of the oil engine, effectively preventing sand and dust from entering the box.
Low noise generator set
(3) Emergency stop switch: an emergency stop switch is installed on the right side of the box to facilitate the shutdown of the unit in case of abnormal conditions.
(4) The box structure material is anti-corrosionCold rolled steel plateThe surface of the box is smooth and flat, and the surface is sprayed with plastic, which can effectively ensure the service life of the box.
(5) Exhaust louver: air guide cover is installed at the front of the box to exhaust air through the air guide slot, greatly reducing the unit exhaust noise and reverse flow of sand and dust.
(6) Box doors and windows: 2mmCold rolled steel plateThere is a glass window to observe the operation status, effectively preventing sand and dust intrusion when the unit is idle.
Inside the box
(1)Unit installation：Generator SetIt is located in the center of the box.
(2) Space: The interior space is spacious, which can store some organic parts and fire-fighting equipment.
(3) Electrical wiring: all electrical wiring in the boxPVCFlame retardant insulating pipe.
(4) Smoke exhaust pipe: it is installed on the top of the box through a flexible damping pad, and is subject to sound insulation treatment.
3. Common chassis
(1) The public base is made of 5mm hot plate bending, and the surface is sprayed with plastic to ensure rust prevention.
(2) It is convenient for customers to move the unit, and the lower part of the chassis is provided with forklift holes.
advantage
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1. Beautiful appearance and reasonable structure;
2. Good sealing performance: rain proof, snow proof, dust proof, and can work in harsh environments;
3. Good safety: fully enclosed box made of 2mm steel plate;
4. The ventilation in the box is smooth, and the temperature is not easy to be too high to ensure the operating power of the unit;
5. Sound proof performance is good: the protective unit also has the performance of reducing noise. The box is effectively noise isolated, so that the unit can effectively reduce part of the noise during operation;
6. High frequency, medium frequency and low frequency PUR flame retardant sound-absorbing cotton is used in the box to effectively reduce different noises from all parts of the unit.
7. EPDM keel sealing strip shall be used to seal the door seam.
8. High efficiency mufflerResistive silencerAnd effectively reduce the noise at the smoke outlet of the unit.
9. Good operability: based on the people-oriented guiding ideology, the designer has fully considered the convenience and safety of operators for oil engine operation.
10. Lifting: if necessary, the unit shall be equipped with 4 lifting devices in the box to facilitate field transportation.
Source of noise
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The following describes the six parts respectively:
exhaust noise
Exhaust noise is a kind of high temperature, high-speed pulsating air flow noise, which is the part of engine noise with the largest energy and most components.It is much higher than the intake noise and the mechanical noise radiated by the engine body, and is the most important part of the total engine noise.Its fundamental frequency is the firing frequency of the engine.The main components of exhaust noise are as follows: low-frequency pulsating noise caused by periodic smoke exhaust, gas column resonance noise in smoke exhaust pipe, Helmholtz resonance noise of cylinder, noise generated by high-speed air flow through valve clearance and zigzag pipe, vortex noise and regeneration noise generated by smoke exhaust system under the excitation of pressure wave in pipe, etc,With the increase of air velocity, the noise frequency increases significantly.
Mechanical noise
The mechanical noise is mainly caused by the vibration or mutual impact caused by the periodic changes of gas pressure and motion inertia force in the running process of the moving parts of the engine. The most serious ones are the following: the noise of the piston crank connecting rod mechanism, the noise of the valve mechanism, the noise of the transmission gear, the mechanical vibration and noise caused by the unbalanced inertia force.Diesel generator setStrong mechanical vibration can be transmitted to outdoor places through the foundation, and then form noise through ground radiation.This kind of structure noise spreads far and has reduced attenuation, which is difficult to isolate once it is formed.
Combustion noise
Combustion noise is the structural vibration and noise generated during the combustion of diesel fuel.The sound pressure level of combustion noise in the cylinder is very high. However, most parts in the engine structure have high rigidity, and their natural frequencies are mostly in the middle and high frequency regions. Due to the mismatch of the response to the sound wave propagation frequency, the peak value of the cylinder pressure level that is very high in the low frequency band cannot be transmitted smoothly, while the cylinder pressure level in the middle and high frequency bands is relatively easy to be transmitted.
Cooling fan and exhaust noise
The fan noise of the unit is composed of eddy current noise and rotating noise. The rotating noise is caused by the periodic disturbance of the cutting air flow of the fan blades;Vortex noise is generated when the air flow is separated on the rotating blade section. The vortex flow caused by the gas viscosity radiates an unstable flow noise.Exhaust noise, airflow noise, fan noise and mechanical noise are radiated through the exhaust channel.
Air inlet noise
Diesel generator setDuring normal operation, sufficient fresh air supply is required to ensure the normal operation of the engine on the one hand, and create good heat dissipation conditions for the unit on the other hand, otherwise the unit cannot guarantee its performance.The air inlet system of the unit basically includes the air inlet channel and the engineAir intake systemThe air inlet channel of the unit must enable fresh air to enter the machine room smoothly, and the mechanical noise and airflow noise of the unit can also be radiated outside the machine room through this air inlet channel.
Generator noise
Generator noise includes electromagnetic noise caused by magnetic field fluctuation between stator and rotor, andRolling bearingMechanical noise caused by rotation.
According to the above noise analysis of diesel generator set.Generally, the following two methods are used to deal with the noise of the generator set:
The noise reduction treatment or purchase of the oil engine room shall be carried out by using sound proof units (the noise is 80db -- 90db).
The noise reduction of the machine room needs to deal with the causes of the above noise separately, and the main methods are as follows:
1. Air inlet and exhaust noise reduction: the air inlet channel and exhaust channel of the machine room are respectively provided with sound insulation walls, and the air inlet channel and exhaust channel are provided with silencers.There is a certain distance in the channel for buffering, so that the intensity of sound source radiation from the machine room to the outside can be reduced.
2. Control of mechanical noise: the top and surrounding walls in the machine room are paved with high sound absorption coefficient absorbersSound insulation materialIt is mainly used to eliminate indoor reverberation and reduce the sound energy density and reflection intensity in the machine room.In order to prevent the noise from radiating outward through the gate, set fire and sound insulation iron doors.
3. Smoke exhaust noise control: the smoke exhaust system is equipped with a special two-stage muffler on the basis of the original primary muffler, which can ensure the effective control of smoke exhaust noise of the unit.If the length of the smoke exhaust pipe exceeds 10m, the pipe diameter shall be increased to reduce the exhaust back pressure of the generator set.The above treatment can improve the noise and back pressure of the generator set. Through noise reduction treatment, the noise of the generator set in the machine room can meet the user's requirements outdoors.
