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How to solve the problem of blocked holes, cracks and perforations in the vibrating screen?

Release time:Apr.04.2024 Views:0

The screen is one of the main components of the vibrating screen.(Stone Crusher) Its main function is to filter materials. Since the screen is in direct contact with the materials during the production process, it is also the main wearing part of the vibrating screen. Breakage and perforation of the screen often occur during the operation. , plugging and other phenomena. If the screen is frequently broken or blocked in a short period of time, it will not only affect the production schedule, but also lead to an increase in investment costs and directly affect the economic benefits of the enterprise. Therefore, understand the causes and solutions of screen cracks, perforations and plugging failures. Measures can effectively save maintenance time, improve work productivity, and ensure orderly and normal production.


Analysis of the causes of screen clogging


The phenomenon of screen damage caused by materials blocking the screen holes often occurs during the production process, especially when the screen mesh is small, this phenomenon is more obvious. Due to the diversity of material particle shapes, various forms of screen hole blockage will occur. The common causes of screen hole blockage are mainly as follows:

1. The particle size of the crushed stone is critical to the mesh size of the screen. During the screening process of the stone, such particles are stuck in the mesh and cannot pass through the screen smoothly, causing blockage. This phenomenon is called critical blockage.

2. There are many materials with shapes that have multiple contact points for the screen holes.

3. If there are more flaky materials in the stone, the flaky materials themselves cannot pass through the screen smoothly during screening. At the same time, the flaky materials are interwoven into a mesh, which hinders the screening of other materials, which will cause clogging.

4. The diameter of the steel wire used to prepare the screen is too thick.

5. The materials to be screened have high moisture and contain viscous substances such as mud and sand. If the materials to be screened contain a lot of mud, or the materials require water washing, the fine-grained stones will stick to each other and form agglomerates due to the intervention of water. The soil adheres to the screen surface, making it difficult to screen materials and causing clogging.

 

solution


1. Change the mesh form. The screen generally uses square holes, and the small mesh uses anti-blocking mesh. If the hole is really blocked, rectangular holes can also be used without affecting the particle size of the stone, but it depends on the service life. Consider, you must pay attention to the mesh direction, otherwise it will affect the screen life cycle. If there is material accumulation, find the cause as soon as possible, such as adjusting the eccentric block of the vibration motor, etc.

2. Reasonably adjusting the tension of the screen is one of the effective measures to reduce screen clogging. Reasonable tension can cause the screen and the support beam to produce slight secondary vibrations, thereby effectively reducing the occurrence of hole blocking. The specific method is to make the tension hook into a constant force tensioning mechanism, that is, on the tensioning bolt Install springs.

3. For materials with more flaky particles, it is necessary to change the material crushing method and the particle size matching of different crushing methods. If the size of the stone crushed by the first jaw crusher is too small, more flaky materials will be produced. , in order to reduce the ratio of needle-flake stones, the first crushing size cannot be too small.

4. The matching of screen mesh and steel wire diameter must be reasonable. Practice has proved that for the same mesh, too thick steel wire will significantly increase the probability of hole blocking.

5. When the moisture content and mud content of the material are high, the screen holes must be cleaned first, and the water spray volume and screen surface inclination of the vibrating screen must be appropriately adjusted. When the moisture content in the material is greater than 5%, if the material is unconditionally dried, The screen surface and screen holes should be selected accordingly. When the moisture content is greater than 8%, wet screening should be used.

How to solve the problem of blocked holes, cracks and perforations in the vibrating screen?


Analysis of the causes of screen rupture and perforation


During the production process, cracks and perforations of the vibrating screen mesh often occur. This phenomenon will directly cause the vibrating screen to be unable to continue working and affect the normal progress of the production line. Let’s analyze the reasons for the cracking and perforation of the vibrating screen mesh and their solutions.

1. The design of the screen reinforcements is unreasonable: the screen has longitudinal narrow reinforcements and longitudinal wide reinforcements. Most of the screen rupture and perforation locations are at the longitudinal narrow reinforcements. If the narrow reinforcement ribs of the screen mesh are narrower than the support beams and do not perfectly match the support beams, and the support beams are wider than the screen mesh reinforcement ribs, the screen mesh will be directly worn, which may cause accelerated rupture and perforation of the screen mesh.

2. Unreasonable feeding: During the production process, if there are uneven feeding, excessive feeding height, excessive feeding flow, etc., it will cause the screen to break and perforate. If the feed to the screen is uneven, it can cause excessive local stress on the screen mesh; if the feed drop exceeds 300mm or the feed flow is too strong, the impact on the screen will be greater.

3. The quality of the screen is unstable: the quality of the screens produced by each manufacturer is different, and some will use the mold casting process for mass production. Due to factors such as ingredient formula, temperature fluctuations, and operator production levels, the quality of the screens may vary. , if the screen material is poor and the mesh fabric is poor, it will not meet the requirements during use and will be easily worn and damaged. Moreover, the low-quality mining vibrating screen mesh has poor wear resistance, flexibility resistance and load-bearing capacity. Rupture and perforation may occur.

4. The worn support beam is not replaced in time: If the support beam is used continuously for too long, it will be sharpened, deviated and uneven after wear, and the sharpened part will be like a knife edge. When the vibrating screen vibrates at high frequency, the sharpened, deflected and uneven support beams will continuously impact, wear and cut the reinforcing ribs of the screen, causing premature rupture and perforation of the screen.

5. Improper screen installation: The mine vibrating screen mesh is tightened and fixed by the bolts on the left and right sides of the screen frame. The screen mesh is installed on the support beam. If the screen mesh is installed, the bolts on the left and right sides of the screen frame will be tightened and fixed. Improper adjustment of the extension length will cause the screen reinforcement and the support beam to be misaligned. The reinforcement will contact the support beam, the support area will be reduced, and the pressure on the screen will increase, which will cause the screen mesh to be narrow and reinforced. The tendon junction is broken and perforated. In addition, if the tension on the screen is too high when tightening the bolts, it will cause a large prestress on the screen, which may also lead to premature rupture and perforation of the screen.

6. The screen plane is not tensioned enough: If the screen is not tensioned, high-amplitude vibrations will cause the screen to vibrate during the operation of the equipment. Usually, the screen will be broken or damaged along the edges of the screen or the edge strips. At the same time, due to the screen If the mesh is not tensioned and the screen surface is not level enough, it will easily cause the screen to deform, and materials will easily accumulate at a certain location, causing uneven stress on the screen and causing damage.

  solution

1. Improve the installation quality of the screen to ensure that the screen reinforcements are perfectly aligned with the support beams.

2. Improve the feeding conditions, reduce the feeding height, reduce the feeding flow rate, and make the feeding uniform. In the feeding mode with strong impact force, if a buffer hopper is installed on the vibrating screen, the direct impact of the material on the screen will consume the excitation force generated by the vibration source, and it is more likely to cause screen damage and screen fatigue.

3. Sign a quality agreement with the manufacturer to ensure the quality of screen supply.

4. Replace the worn support beams in time. When there is no new support beam to replace, place a rubber pad between the screen and the worn support beams to reduce and avoid the wear of the screen mesh by the sharp corners of the support beams.

5. Choose a high-manganese steel wire braided screen with high elasticity and wear resistance, which is not only strong and durable, has a long life, but also has higher screening efficiency.

6. When installing or replacing the screen, 3-4 people should work at the same time. Lay the screen flat on the screen frame, then put the screen compression ring on it, and fix it symmetrically with screws in the vertical direction of the screen. , after the screen has no folds and is evenly tightened, insert the screws into the screw holes and tighten them slowly and evenly one by one. And always check the tension of the screen and check whether the screen is compacted.

Screen selection

The quality and the selection of relevant parameters during design directly affect the screening process of materials, which in turn affects the processing capacity and screening efficiency of the vibrating screen. Therefore, the correct selection and use of the screen directly determines the grading and grading of the product. Quality, high-quality screens must meet the following conditions:

(1) The material must be special wear-resistant steel wire. The chemical composition of C and Mn should be high enough, while Si, P and S should be as low as possible.

(2) The weaving form is reasonable, and the technology must ensure that the steel wire is tightly woven and must not be loose.

(3) The overall dimensions and edge shape must match correctly with the tensioning plate and screen frame on the screen machine.

(4) The screen mesh is flat and the opposite sides are parallel.

(5) The wrapping form is reasonable, which is conducive to screen tensioning.

As an indispensable accessory of the vibrating screen, the screen will encounter varying degrees of damage due to various reasons in actual production. Xingaonai Heavy Industry recommends: Once the screen is found to be faulty or damaged during the production process, It is necessary to stop the machine in time to repair and replace the screen to ensure normal and orderly production.