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Correct selection and connection method of belt conveyor belt
Published: 2015-4-9 11:38:19 Source: Conveyor http://shxierui.com Author: Hai Yu sound machine
The selection of the conveyor belt of the belt conveyor is based on factors such as the length of the conveyor, the conveying volume, the tension of the conveyor belt, the characteristics of the materials being conveyed, the receiving conditions, and the working environment. In addition to the longitudinal tensile stress, the conveyor belt is also subject to the bending stress passing through the rollers and idlers during the running process. The damage of most conveyor belts is the wear of the working surface layer and edges, which is caused by the impact of large, sharp materials to cause breakdown, tearing and peeling.
1. Pre-selection of conveyor belts. The selection of conveyor belts needs to consider a variety of factors, mainly: the conveyor system's related requirements for the conveyor belt; the terrain environmental conditions and safety requirements; the type, shape, granularity and characteristics of the conveying materials With or without thermal and chemical effects; required maximum bandwidth, working tension and conveying capacity; minimum diameter of the drum; trough formation and lateral stiffness; load support; length of curve and transition section; tensioning method and stroke; receiving point and receiving Material conditions. And the operating cycle of the conveyor belt: requirements for impact resistance and tear resistance; joint conditions; and should meet the following requirements:
(1) For short-distance belt conveyors, polyester fabric core conveyor belts should be used. For belt conveyors with large capacity, long distance, large lifting height, and high tension, steel wire core belts should be used.
(2) The material being conveyed contains large-size block materials. When the direct drop of the receiving point is large, an impact-resistant and tear-resistant conveyor should be used.
(3) The maximum number of layers of the layered fabric core conveyor belt should not exceed 6 layers: when the material being conveyed has special requirements for the thickness of the conveyor belt, it can be appropriately increased.
(4) Flame-resistant conveyor belts must be used for underground belt conveyors.
2. Selection of cover layer The selection of cover layer includes cover material, surface morphology and thickness.
The main components of the cover are various rubbers and plastics. In most climates, rubber can work normally with an inclination of not more than 18 °. The normal operating angle of PVC tape is below 12 °. PVC is not as good as rubber in terms of resilience, but it has better flame retardancy, discharge and cleaning properties. The properties of various rubbers are also very different. For example, natural rubber and styrene-butadiene rubber have good energy absorption and abrasion resistance; ethylene-propylene rubber is particularly heat-resistant; butyl cyanide rubber has good oil resistance: butyl-butyl rubber is both heat-resistant and Resistant to oxidation chemistry. Therefore, the choice of the type of covering material must be comprehensively considered according to the type of conveying material, operating conditions and working environment.
The increase in the thickness of the cover layer is conducive to improving the impact resistance and abrasion resistance of the conveyor belt. Especially today, the cotton canvas belt core has been replaced by the synthetic fiber fabric belt core, the performance of the belt core has been greatly improved, and the thickness is relatively thin. In order to improve the overall performance of the conveyor belt, it is necessary to correspondingly increase the thickness of the cover layer in order to give full play to its advantages and increase the service life of the conveyor belt. However, the excessive thickness of the lower cover layer increases the running resistance of the conveyor belt.
The design of the thickness of the cover layer is based on the wear speed, the receiving conditions, the heat resistance of the cover layer, the impact resistance, and the operating cycle of the conveyor belt.
3, the joints of the conveyor belt The joint type of the conveyor belt should be selected according to the type of the conveyor belt and the characteristics of the belt conveyor; the steel wire core conveyor belt should use vulcanized joints; the multilayer fabric core conveyor belt should use vulcanized joints; the fabric core convey Adhesive heads should be used for the belt, and mechanical joints can also be used.
(1) Mechanical card connection method: When the mechanical card is connected, the strength of the belt will be reduced due to the decrease in the strength of the joint. This is particularly significant for the whole core plastic belt. Therefore, mechanical card coupling is only suitable for short belt conveyors or occasions requiring shorter maintenance time. The mechanical card is selected according to the thickness of the conveyor belt.
(2) Vulcanization method: The rubber band is cut into a step shape (one step for each layer of canvas), and the width of the step is generally equal to 150mm. Then the surface is filed and coated with raw rubber paste for overlap, and the raw film is covered at the upper and lower joints, and heated and pressurized for vulcanization. The temperature should be about 140 ℃, the temperature should be slowly raised, and the temperature of each point of the vulcanization plate should be kept uniform. The heat preservation time starts from 140 ℃. After the canvas layer has reached the heat preservation time, stop heating and allow it to naturally cool to normal temperature. The belt conveyor can Used normally.
(3) Cold bonding method: Cut and peel the conveyor belt into stepped hairs as required, clean the surface with propylene copper, and mix with the two-component conveyor belt special glue according to the blending ratio on the instruction sheet to mix evenly and completely. Apply on both sides of the peeling layer. After applying for the first time, leave it for 5-10 minutes, and then apply it a second time when the adhesive layer is not pulled into segments by hand. When it is still left for 10-15 minutes, when the adhesive layer is no longer thin, , Press the two layers according to the steps to align the seams, and use a flat-head hammer to smash them evenly with hands; use glue to flatten the seams, press the pressure evenly, and place them for 24 hours before use.
(4) Plasticizing method: For the whole core plastic conveyor belt, the overlap length is 300mm in width, 500mm in bandwidth 650mm and 500mm, and the upper end of the plastic belt is covered with the other end before plasticizing. Cover and peel off, and then put 1mm thick PVC plastic sheet on both ends of the pad. Heat and pressurize to plasticize. The temperature should also be slowly raised from room temperature to about 170 ° C in about 30 minutes, pressurized again, and then cooled to normal temperature and released. Multi-layer plastic conveyor belts can be cut and stripped into a step shape with reference to the dimensions of the multi-layer rubber belts for plasticization.
After the belt conveyor is used for a long time, the belt may slacken or the belt may be torn due to material reasons or improper operation during use. Therefore, the belt needs to be repaired or replaced. Here we summarize the above 4 points of the connection method of the joint after the conveyor belt is repaired or replaced. I hope users can refer to it.
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