The possible reasons for the noise emitted by diesel engine fire pumps are as follows:
(1) The influence of the rotating blades of diesel engine fire pumps on the engine body, the residual volume of the vacuum device of diesel engine fire pumps, and the sound of pressure oil in the exhaust blind gap;
(2) The influence of exhaust valve disc on valve seat and support of diesel engine fire pump;
(3) The echo and foam in the diesel engine fire pump box burst;
(4) The bearings of the diesel engine fire pump make noise;
(5) The noise generated by a large amount of oil and gas hitting the oil baffle during the operation of the diesel engine fire pump;
(6) Other: For example, noise caused by transmission, fan noise of air-cooled water pumps, etc.
The motor noise of diesel engine fire pumps is a key factor.
The description is as follows:
The effect of rotating blades on cylinder walls. If the material is not designed, manufactured, or used properly, the rotating blade slider may not be smooth, or due to the presence of exhaust dead zones, incompressible oil may cause the rotating blade head to not always run close to the cylinder wall, resulting in the rotating blade hitting the cylinder wall. Therefore, a circular arc surface should be used to separate the intake and exhaust structures. Eliminate the dead zone of the exhaust diversion groove. When using a straight separation structure, the distance between the exhaust endpoint and the tangent point should be minimized as much as possible. For rotary vane pumps below 70L/s, considering the actual thickness of the rotary blades, it is recommended to take 7ml/Omm, and larger values should be taken for large water pumps. When the rotor is too close, there is only a narrow band contact between the rotor slot and the rotor head. When the rotor rotates to the cutting point, the sealing effect is poor, which can affect the pumping speed of the diesel engine fire pump and even the ultimate pressure of the diesel engine fire pump. It can be seen that this structure cannot completely eliminate the exhaust dead zone, thereby limiting the level of noise reduction.
It should be pointed out that the gap between the rotating blade and the groove is too large to reduce performance. Therefore, it is necessary to ensure reasonable tolerance and shape tolerance values, pay attention to the thermal expansion of the rotating blades, avoid the rotation of the rotating blades and grooves, pay attention to the cold oil viscosity of the oil, design sufficient spring force for the rotating blades, and when using circular arc surface separation, the additional eccentricity at the center of the rotor should not be too large. Otherwise, the rotating component will pass through two arcs, which will result in a tendency to separate from the cylinder wall at the intersection and instead cause impact noise. Generally speaking, small water pumps can be 0.20-0.25mm, and large water pumps can be added appropriately.
The sound of exhaust dead angle pressure oil and residual volume pressure oil. When the diesel engine fire pump reaches its maximum pressure, two types of pressure oil are connected to the vacuum chamber and injected into it at high speed, colliding with the rotor and cylinder wall to produce sound. The size and position of these two books are related to noise.
Valve disc impact noise on valve seat and supporting components
The gas intake is large, the pump circulates a lot of oil, the valve plate noise is high, the valve jumps high, the valve area is large, the valve plate noise is also large, and the valve plate material also has a certain impact. The noise of rubber valve plates should be better than that of steel plates or laminated plates. To achieve this, it is necessary to control the oil intake, and the valve plate should be closed promptly and strictly. Pay attention to the material selection and structure of the valve.
As the echo inside the box increases and the air volume due to bubble rupture increases, the noise also increases.
Therefore, when the air is open or the atmosphere is open, the noise will significantly increase. If the air balance can be adjusted, then the air balance can be adjusted reasonably.
The noise generated when discharging a large amount of gas and oil during the impact of components such as oil baffles. If the parts are not rigid enough or not tightened, vibration and collision will increase noise. Therefore, the oil baffle not only needs to have sufficient rigidity and sealing, but also rubber can be used to avoid collision noise caused by vibration and improve oil retention when in contact with other components (such as the fuel tank).
Reciprocating vacuum pumps, rotary vane vacuum pumps, slide valve vacuum pumps, Roots vacuum pumps, and other vacuum pumps that suction, compress, and discharge gases through rotation mainly generate noise due to piston wear. Vacuum pumps should avoid approaching maximum vacuum or exhaust pressure. Working in this area is not only inefficient, but also unstable, prone to vibration and noise. For high vacuum vacuum pumps, cavitation often occurs when working in this area. The obvious signs of this phenomenon are noise and vibration inside the pump. Cavitation can damage parts such as the pump body and impeller, rendering the pump inoperable. According to the above principle, when the required vacuum or air pressure for the pump is not high, a single-stage pump can be preferred. If the vacuum degree or exhaust pressure is high, a single-stage pump cannot always meet the requirements, or a larger air volume is required at higher vacuum degrees, that is, a flat performance curve is required at higher vacuum degrees, so a two-stage pump can be used. When the vacuum requirement is above -710mmHg, a water ring air pump or a water ring Roots vacuum unit can be used as the vacuum pumping device.
In addition, oil-free vortex vacuum pumps can be used to reduce noise. The compression process is relatively slow. There are two or three compression processes simultaneously. The compression chamber is symmetrical relative to the crankshaft. In this way, the operation process of the pump is stable, and the driving torque and gas shock fluctuations are small, thereby reducing the noise and vibration of the pump.
Imported vacuum pumps can be widely used in vacuum drying, food vacuum packaging, solvent gas recovery, carbon dioxide gas recovery, vacuum forming, vacuum concentration, vacuum defoaming, central vacuum systems, vacuum heat treatment and other fields.
The correct use of diesel engine fire pump engines is an important factor in extending the service life of water pumps and reducing economic losses.
