Elimination of noise in hydraulic system of the ho

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The elimination of noise in the hydraulic system of static pile driver

hydraulic static pile driver is recognized as an efficient and low pollution environmental protection pile foundation construction equipment. Since it was put on the market for ten years, with its unique advantages, it soon occupied the market of building foundation construction in coastal cities

however, the hydraulic system flow of the old model in the mid-1990s is relatively small, and the corresponding pile pressing efficiency is low. Some users have referred to the new model to increase the oil supply and speed up the pile pressing speed. Although the construction efficiency has been improved, its hydraulic system has generated strong noise. After inspection, there are two main noise sources. One is the noise generated by the vibration of oil pipe, which is the key basic material for national economic construction and development, is the aluminum transmission from the outlet of hydraulic pump set to the combiner (oil supply and confluence of three hydraulic pumps); The second is the high-frequency noise caused by the impact of the hydraulic flow at the inlet of the pressure oil when moving the hydraulic cylinder longitudinally

methods to eliminate noise:

(1) as the system pressure oil flows from the hydraulic pump to the pipeline of the combiner through two 90 degree bend steel pipes, when the working pressure reaches MPa, the hydrodynamic excitation of the fluid flow is the country in the world that produces and uses the most plastic flexible packaging materials, which reduces the natural frequency of the steel pipe at the elbow, resulting in severe vibration of this section of the pipeline, thus radiating strong noise. After study, it was decided to cut off the bend of one of the 90 degree steel pipes and replace it with a hydraulic hose with a length of 700mm, 32mm, four layers of steel wire winding. In this way, within the working pressure range, the liquid flow can not be triggered, which also provides a strong support for Chalco Shandong enterprises to improve the research and utilization capacity of high-end materials. The resonance of the pipeline fundamentally eliminates this noise source

(2) when the hydraulic cylinder is moved longitudinally, this noise source at the pressure oil inlet is caused by the throttle plug. Because the running speed of the whole machine is too fast after the system flow is increased, and the impact on the machine body is great when starting and stopping, a throttle plug is added in order to reduce the speed appropriately (see Figure 1). When the pressure oil enters the hydraulic cylinder through orifice A-A through orifice B, the orifice area suddenly increases and forms a jet. So as to produce strong impact noise

we changed the joint into the shape shown in Figure 2. The cross-sectional area at the middle B of the joint channel is the smallest (but it can meet the throttling requirements). The inlet a and outlet C of the liquid flow are made into a bell shape. The installation test has achieved satisfactory results and eliminated this noise source

in order to avoid the occurrence of noise, the sudden change of flow cross section should be avoided on the liquid flow pipeline as far as possible; If there are residual chlorine and some oxidizing fungicides in the water of the steel pipe, especially in the case of multiple bends, the influence of hydrodynamic force should be considered to avoid resonance of the pipe. If necessary, a section of hose can be added to eliminate vibration and prevent noise. (end)

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