The blade is an industry with high certainty, large market capacity and clear profit model in wind power components. With the easing of supply and demand tensions, the blade industry will experience a process from chaos to oligarch, from shortage to equilibrium, from profiteering to small profits. The blade is an industry with high certainty in wind power components, large market capacity and clear profit model. With the easing of supply and demand tensions, the blade industry will experience a process from chaos to oligarchy, from shortage to equilibrium, from profiteering to small profits. The market will form several oligarchs of more than 1,000 sets, which will be higher than the industry average. Profitability, while other vendors will gradually be marginalized. With the expansion of the wind power blade market, both cost and price will decline, but the cost reduction of enterprises with scale, technology and cost advantages will exceed the price reduction rate, and the profit will exceed the average level. The future industry competition pattern requires manufacturers to expand in size, reduce costs, and maintain certain advantages in technology. Christmas Light,Outdoor Christmas Decorations,Outdoor Christmas Lights,Christmas Tree Lights Shanxi KathayTech Co.,ltd. , https://www.jdsmachine.com
Reasons for problems with the blades of the Reitz fan
Main reasons: imperfect design, production defects, natural causes and improper operation.
1 design is not perfect
1.1 Faced with the pressure to reduce costs
In order to pursue higher profits, management requires the design of low-cost components in order to give enterprises more space. Design departments sometimes have to make compromises, such as reducing the blade root diameter to reduce the cost of the hub and blades, but the reduced root size can result in insufficient blade strength, such as poor quality but price Cheap raw materials, which often lead to fatal flaws in the blade.
1.2 Unauthorized changes to the production process.
1.3 limit design
The design of the blade needs to take into account the requirements and cooperation of other components of the unit. For example, the distance between the tower and the blade is usually a factor to be considered when designing the strength of the blade. The spindle and the bearing also require the weight of the blade. If these parameters are not considered Weeks will bring the blade design to its limit.
1.4 Safety quality is reduced
2 production defects
2.1 use of unreasonable materials
2.2 not strict quality control
2.3 The production process is too complicated to produce consistent quality products.
3 natural reasons
Mainly include: lightning strikes, particles in the air, high speed wind, shear wind, bad weather, fatigue life
4 Improper operation and maintenance
4.1 Super rated power operation
4.2 out of control
When the machine's propeller system fails, the brakes on the machine will not stop the impeller, the blades will be out of control, and will continue to rotate rapidly, which will cause the blades to be thrown, causing a catastrophic accident of the fan.
4.3 lack of preventive maintenance
In the daily operation and maintenance of the fan, the blades are often not taken seriously. However, the aging of the leaves changes with time under adverse conditions such as sunlight, acid rain, wind, self-vibration, sand, salt spray. Once the problem is discovered on the ground, it means the problem is very serious. The daily maintenance of the blade is difficult to inspect and maintain to the blade. In many wind fields, the blade will naturally crack due to aging, trachoma, surface wear, lightning damage, lateral cracks, etc. If these problems are solved in daily maintenance, you can avoid the high maintenance costs in the future and reduce the economic losses caused by the downtime.
Common Reitz fan blade damage type
There are mainly the following types: general damage type, leading edge corrosion, leading edge cracking, trailing edge damage, blade root fracture, surface crack, lightning damage.
Reitz fan blade crack maintenance
The rotor system is an important part of the rotating machinery, and the blade fracture caused by the crack propagation of the rotor is extremely harmful to the rotating machinery. At present, there are many researches on the vibration characteristics of rotor blade cracks. There are few researches on the diagnosis and identification of rotor blade crack faults. The identification of rotor blade cracks and their extension is of great significance for the final diagnosis of blade crack faults. In the mechanical equipment "target=_blank> mechanical equipment fault diagnosis, the classical signal processing method based on stationary process - Fourier transform analysis and windowed Fourier analysis - is usually used, which is given only from the time domain or the frequency domain. The statistical average result of the signal cannot simultaneously take into account the overall and localized features of the signal in the time domain and the frequency domain, and these localized features are often characterized by faults.
The stress is concentrated due to cracks. According to the finite element calculation and analysis, under the action of water pressure and centrifugal force, the large stress area is mainly distributed on the periphery of the runner blade, and the equivalent stress calculated according to the third strength theory is distributed along the periphery of the blade. Generally, there are four high-stress zones in the runner blade. Their position is near the upper crown of the blade inlet side (pressure distribution surface); the middle part of the front side of the blade outlet; the back of the blade is close to the upper crown; the blade and the lower ring In the connection area. Casting defects and welding defects. Casting pores, cast blisters, etc. may become crack sources under the action of external stress, causing cracks. Since the thickness of the runner blade is different from the thickness of the upper crown and the lower ring, shrinkage holes, looseness, and the like are easily generated during the cooling process. If the welding process is not properly welded or the welder does not weld according to the requirements of the welding process, cracks may occur in the weld and heat affected zone.
In the original design problem, the transition R angle between the runner blade and the upper crown and the lower ring is smaller, causing stress concentration. The reason for the operation, long-term low load, overload or running in the vibration zone will cause the blade to crack or crack under the action of alternating stress. Non-destructive flaw detection of cracks During the overhaul, the non-destructive inspection of the runners is carried out, and it is necessary to deal with the defects in time to eliminate hidden dangers. Defects such as severe cracks can be found by visual inspection of the naked eye and magnifying glass, but smaller defects and internal defects must be inspected by non-destructive testing.
Commonly used non-destructive testing methods are as follows: magnetic particle testing, penetrant testing, ultrasonic testing, metal magnetic memory, radiation testing, etc.
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Editor: (Hardware Business Network Information Center) http://news.chinawj.com.cn