Mixed Fertilizer Zone – Test Your Knowledge 11.21

This issue involves the relationship between the height of the elevator, the speed of the chain, the size of the hopper, and the maximum amount of material at any given moment; I’m not quite sure, I’m still learning*

The loading capacity of the elevator is related to the width of the bucket; the faster the speed, the more can be lifted. Specific issues regarding coordination have not been studied, as what is purchased are already finished products

The last edit to this post was made by huchsh on 2009-11-21 at 09:35. The lifting capacity of the conveyor is related to the size of the hopper, but not to its speed. It is not advisable to set a high constant speed, as this can lead to unstable operation and spillage of material; this in turn causes accumulation of material at the bottom, lifting the counterweights and resulting in chain jams and machine shutdowns

This post was last edited by hujiayue on 2009-11-21 09:40. The amount of material handled by the conveyor is high and the hopper is large; this has nothing to do with speed

The hoppers of the elevator are available in various specifications such as 250, 315, 400, 500, 630, etc., and there are also types like medium hopper ZH, deep hopper SH, and shallow hopper Q. The lifting amount is related to the hopper type and the lifting speed. The lifting speed for the TH type is generally 1.25~1.7 m/s, while that for the TGD type is generally 1.36~2 m/s.

1. Slipping of the bucket belt: (1) A bucket elevator relies on the frictional torque between the bucket belt and the drive shaft of the head pulley to lift materials; if the tension in the bucket belt is insufficient, it will cause the belt to slip. At this point, the machine should be stopped immediately, and the tensioning device adjusted to tighten the hopper belt. If the tensioning device is unable to fully tension the hopper belt, it means that the travel distance of the tensioning device is too short, and it should be adjusted again. The correct method of adjustment is: loosen the connections of the conveyor belt, set the tensioning device on the idler wheel to its highest position, feed the conveyor belt into the head of the elevator, pass it through the drive wheel and the idler wheel, and connect its ends together so that the conveyor belt is in a state of being tensioned but not overly tight. Then fully tension the tensioning device. At this time, the tensioning stroke of the adjustment screw of the tensioning device that has not yet been utilized should be no less than 50% of the total stroke. (2) Overloading of the elevator: When the elevator is overloaded, the resistance torque increases, causing the bucket belt to slip. At this point, the feeding rate of the material should be reduced, and efforts should be made to ensure uniform feeding. If slippage does not improve even after reducing the feed rate, it may be due to too much material accumulated inside the machine or the hopper being blocked by debris; the machine should be stopped for inspection in order to resolve the issue. (3) The inner surfaces of the drive shaft for the head wheel and the conveyor belt are too smooth; this reduces the friction between them, resulting in slippage of the conveyor belt. At this time, a layer of glue can be applied to the drive shaft and the inner surface of the hopper belt to increase friction. (4) Poor rotation of the bearings on the drive wheel and the idler wheel: When these bearings do not rotate properly, the resistance torque increases, causing the conveyor belt to slip. At this time, the oil can be drained and refilled or the bearings can be replaced. 2. Deviation of the conveyor belts (1) Improper installation of the drive shafts for the idler wheel and the drive wheel. The improper installation of these drive shafts is manifested in the following aspects: first, the drive shafts of the idler wheel and the drive wheel are not parallel to each other and are not within the same vertical plane ； Second, both drive shafts are installed in a horizontal position and are not in the same vertical plane ； Third, the two drive shafts are parallel, located in the same vertical plane and are not horizontal. At this time, the hopper belt deviates from its path, which can easily lead to collisions between the hopper and the barrel, as well as tears in the hopper belt. The machine should be shut down immediately to resolve the fault. It is ensured that the drive shafts of the top wheel and the bottom wheel are installed in the same vertical plane and are both in a horizontal position; the vertical deviation of the machine’s centerline at a height of 1000 mm does not exceed 2 mm, while the cumulative deviation does not exceed 8 mm. (2) Incorrect hopper belt joint: An incorrect hopper belt joint means that, after the hopper belt is joined together, the edges of the belt are not on the same straight line. During operation, the belt of the hopper becomes tight on one side and loose on the other, causing the belt to shift toward the tight side and resulting in deviation. This leads to insufficient filling of the hopper, incomplete unloading, increased backflow of material, and reduced productivity; in severe cases, it can cause the belt to get stuck or tear. At this point, the machine should be stopped to repair and reconnect the joint properly. 3 Excessive return material: The return of material by the elevator refers to the situation where the material is not completely discharged from the machine at the discharge point, and some of it returns into the elevator’s frame. In lifting operations, if too much material returns to the elevator, it will inevitably reduce production efficiency, increase power consumption, and raise the rate of material fragmentation. The reasons for excessive return material are as follows: (1) The speed at which the hopper operates is too high. Different materials are lifted by the elevator, and thus the operating speed of the hopper varies; generally, when lifting dry powders and granules, the speed is around 1~2 m/s ； When lifting bulk materials, the speed is 0.4~0.6 m/s ； When lifting wet powders and granules, the speed should be 0.6~0.8 m/s. The speed is too high, resulting in premature unloading and thus backflow of material. At this time, the speed of the hopper should be appropriately reduced depending on the material being lifted, to prevent backflow. (2) The unloading tongue plate at the machine head outlet is not installed properly; it is too far from the unloading position of the hopper, which causes material to flow back. The position of the tongue plate should be adjusted promptly to prevent backflow. 4. Hopper detachment: Hopper detachment refers to the phenomenon in production where the hopper falls off the conveyor belt. When a hopper falls, it produces an abnormal noise; the machine should be stopped for inspection promptly, otherwise more hoppers will become deformed or fall off ； At the location where it connects to the hopper, the hopper belt tore. The main reasons for the bucket to fall off are: (1) Excessive feeding, which leads to the accumulation of material inside the machine frame, increases the lifting resistance, and hinders the proper operation of the bucket; this is the direct cause of the bucket falling off or becoming deformed. At this point, the machine should be stopped immediately, the plug under the base should be removed to remove the accumulated material inside the base, a new hopper should be installed, and then the machine can be restarted for operation. At this point, reduce the feeding amount and strive for uniformity. (2) The feed inlet is usually located too low; during production, the conveyor bucket automatically picks up the material that enters through the feed inlet. If the feed inlet is positioned too low, it will prevent the hopper from having enough time to collect the material, causing most of the material to go into the machine base instead, which hinders the hopper’s ability to scoop up the material. And when the material is in block form, it can easily cause the hopper to deform or fall off. At this time, the feed inlet position should be adjusted above the centerline of the bottom wheel. (3) The material of the hopper is of poor quality and has limited strength. The hopper is a component that bears loads in the elevator, so high requirements are placed on its material; when installing it, it is necessary to use materials with good strength as much as possible. Generally, hoppers are welded or stamped from ordinary steel plates or galvanized sheets, and their edges are folded or wrapped with wire to enhance the strength of the hopper. (4) Failing to clear the debris accumulated in the machine base when starting up. During production, sudden power outages or other factors can cause the machine to stop operating. If the debris in the machine base is not removed before restarting, it can lead to excessive stress on the hopper, resulting in its breakage and detachment. Therefore, between shutdown and startup, the accumulated physics inside the frame must be cleared to prevent the hopper from falling off. Additionally, regularly check whether the connection between the hopper and the conveyor belt is secure. If loose screws, missing screws, or a tilted or damaged hopper are detected, repairs or replacements should be carried out promptly to prevent more serious accidents. 5 Bucket belt tear: The bucket belts in elevators are usually canvas belts, though tape and chains are also used sometimes. Under the combined effect of various faults, canvas belts and tapes are prone to tearing, which is one of the most serious failures. Generally, misalignment of the hopper belt and the detachment of the hopper are the processes that most easily cause tearing of the hopper. The cause should be identified promptly and thoroughly to resolve the fault. Additionally, the presence of foreign objects with sharp edges in the material can also cause cracks in the hopper. Therefore, in production, wire mesh or magnets should be installed at the feed inlet to prevent large foreign objects from falling into the machine base.

It relates to the amount of material lifted by the elevator and the relationship between the size of the hopper and the speed. Answer: 1. A larger hopper allows for more material to be lifted (with constant speed). 2. A smaller hopper results in less material being lifted (with constant speed). 3. As for the speed, it can be adjusted according to production needs; a higher speed means more material is lifted, while a lower speed means less material is lifted

The greater the amount of material lifted by the elevator, the larger the hopper must be, and the lifting capacity of the elevator also needs to increase, with a faster speed required as well.

Overview of bucket elevators: Bucket elevators are used for vertically lifting lumpy and granular materials such as limestone, coal, gypsum, clinker, and dry clay that have been crushed, as well as powdered materials like raw material, cement, and coal powder. Depending on the speed at which the hopper moves, bucket elevators can be classified into three types: centrifugal discharge, gravity discharge, and mixed discharge. Centrifugal discharge hoppers have a high conveying speed, and are suitable for transporting materials with low abrasiveness such as powders, granules, and small lumps ； Hoppers with gravity discharge have a slower discharge rate, and are suitable for transporting bulk materials with high specific gravity and high abrasiveness, such as limestone and clinker. The traction components of bucket elevators include chain rings, plate chains, and belts, among others. The structure and manufacturing of the chain link are relatively simple, and its connection to the hopper is very strong. When transporting materials with high abrasiveness, the wear on the chain is low, but its weight is considerable. Plate chain structures are relatively robust and have a low weight, making them suitable for hoists that need to lift large quantities of material. However, their hinge joints tend to wear out easily. The structure of conveyor belts is simple, but they are not suitable for transporting materials that are highly abrasive. Ordinary conveyor belts can handle temperatures up to 60°C; belts with steel cords can withstand temperatures of up to 80°C, while heat-resistant belts can handle temperatures of up to 120°C. Chain and plate chain conveyors can handle temperatures as high as 250°C. 　　Main features of bucket elevators: 1. Low driving power; it uses an inlet feeding system, an induced discharging method, and a densely arranged set of large-capacity hoppers. During the lifting of materials, there is almost no backflow or material digging, resulting in low unnecessary power consumption. 　　2. It has a wide range of applications; such elevators have few requirements regarding the type and properties of the materials handled. They can lift not only ordinary powdered or small-grained materials but also those with high abrasiveness. They offer good sealing properties and result in less environmental pollution. 　　3. It features good operational reliability; advanced design principles and manufacturing methods ensure the reliability of the entire unit, with a fault-free operation time of over 20,000 hours. It has a high lifting height. The elevator operates smoothly, which allows for a high lifting height to be achieved. 　　4. It has a long service life; the feeder of the elevator uses an inflow mechanism, eliminating the need for buckets to remove material, and there is little compression or collision between the materials. The machine is designed to minimize material spillage during feeding and unloading, thereby reducing mechanical wear. 　　The conveying principle of a bucket elevator is as follows: the buckets pick up the material from the storage area below, lift it to the top using a conveyor belt or chain, turn it downward after passing over the top wheel, and then the bucket elevator pours the material into the receiving trough. The drive belt of a belt-driven bucket elevator is usually made of rubber and is installed on the lower or upper drive drum, as well as on the upper and lower redirecting drums. Bucket elevators with chain drive are generally equipped with two parallel drive chains, a pair of drive sprockets on the upper or lower side, and a pair of idler sprockets on the lower or upper side. Hopper elevators are generally equipped with enclosures to prevent dust from flying inside them. Overview of multi-functional hoists: Multi-functional hoists are a type of electric hoist that can be used both on the ground and in the air. They are widely used in the construction industry, offering large handling capacities, high lifting heights, and stable and reliable operation. The rated lifting capacity of the multi-functional electric lift is 500 kilograms/300 kilograms; its maximum lifting height is 100 meters. The lifting speed of this lift when carrying a load of 500 kilograms is 5.5 m/min ； Lifting capacity: 300 kg; operating speed: 8 m/min. The rated lifting capacity is 500 KG, with 300 KG being the actual lifting capacity ； 　　Maximum lifting height: 100M 　Lifting speed: 5.5M/MIN, 8M/MIN ； 　　The motor powers are as follows: 1.5kw, 1KW, 1.5KW, 0.4KW ； 　　The power supplies available are single-phase and three-phase. 　　Classification of multi-functional elevators: Multi-functional elevators are divided into the DTS-30 multi-functional elevator and the DTS-50 multi-functional elevator, as well as the DTS50-80-A, DTS50-80-B, DTS30-80-A, and DTS30-80-B models. Working principle of these elevators: The D-type bucket elevator consists of a moving part (bucket and conveyor belt), an upper section equipped with drive rollers, a lower section equipped with tensioning rollers, an intermediate casing, a driving mechanism, and a reverse braking device. It is suitable for transporting loose materials with a bulk density of ρ＜1.5 t/m3, such as powdered, granular, and small lumpy materials that are non-abrasive or semi-abrasive, including coal, sand, coke dust, cement, and crushed ore. Structural configuration of TD type bucket elevator: The drive system of the TD type bucket elevator comes in two forms, equipped either with YZ type reducers or ZQ (or YY) type reducers. The YZ type shaft reducer is mounted directly on the spindle head, eliminating the need for a transmission platform or couplings, which results in a compact structure and lower weight. It also features a special-shaped roller check valve, ensuring reliable backstop functionality. This reducer has low noise, operates smoothly, and floats with the main shaft, thereby eliminating installation stress. 　　 Working principle of the HL-type chain-driven centrifugal bucket elevator: The HL-type chain-driven centrifugal bucket elevator consists of a moving part (the bucket and the traction chain), an upper section equipped with drive sprockets, a lower section fitted with tensioning wheels, an intermediate casing, a drive mechanism, and a reverse braking device. The hopper of this elevator is arranged in a discontinuous manner; loading is carried out using the \"picking method\", while unloading is done via the \"centrifugal feeding method\". The traction mechanism of this elevator consists of two endless chains. 　　Working principle of TH series bucket elevators: The TH series bucket elevators are suitable for transporting powdered, granular, and small lumpy materials that are non-abrasive or have low abrasiveness. The TH type is a ring-chain bucket elevator that uses mixed or gravity unloading, with digging-type loading. The pulling element is a high-quality alloy steel highly circular chain. The middle casing is available in single and dual channel versions to provide constant-force automatic tensioning for the weight box inside the machine. The sprocket features a replaceable rim composite structure. Long service life, and the rim replacement is simple. The lower part is equipped with a gravity-based automatic tensioning device that maintains a constant tension, preventing slippage or chain detachment. It also offers a certain degree of flexibility in case the hopper gets stuck due to unexpected factors, thus providing effective protection for components such as the lower shaft. This bucket elevator is suitable for transporting powdery, granular, or small lumpy materials with a bulk density of less than 1.5 t/m3 that are easy to remove. Such as coal, cement, gravel, sand, fertilizers, grain, etc. The TH type bucket elevator is used for the vertical transportation of various bulk materials. Suitable for transporting powdered, granular, and small lumpy materials, with material temperatures below 250°C. 　　 Working principle of NE series plate-chain bucket elevators: The NE series plate-chain bucket elevators feature an inlet-type feeding system; materials flow into the hopper and are lifted to the top by the plate chain, after which they are discharged due to their own gravity. This series of elevators comes in a wide range of specifications (11 types in total, from NE15 to NE800), with a broad range of lifting capacities ； It also features high production capacity and low energy consumption, and can gradually replace other types of elevators; its main parameters are shown in the table below. This machine features a fully enclosed casing, resulting in a low chain speed and almost no material return, which leads to low reactive power loss, low noise, and a long service life. 　　 Working principle of the DZC series vibration lift: The DZC series motor-driven vertical vibration lift is composed of a lifting trough, a vibration motor, a vibration damping system, and a base. These elevators use vibration motors as the source of vibration. Two vibration motors of the same model, fixed on the elevator trough, are installed with their centerlines intersecting at a certain angle and rotating in opposite directions in a self-synchronized manner. The centrifugal forces generated at various positions of the eccentric masses attached to these vibration motors cause back-and-forth movements in the direction of projection, resulting in continuous vibration of the entire structure supported by the shock absorbers. This causes the material inside the elevator trough to be lifted upward. Once the material falls into the feed trough, it is also lifted, allowing it to come into full contact with air while also serving to dissipate heat and cool the material. This elevator can vertically transport powdered, lumpy, and short-fibered solid materials (except those that are sticky or prone to caking), and it can also be used for drying and cooling the materials. It comes in two structures: open-type and closed-type. It can also be specially designed according to the user’s needs. 　　Main technical parameters of bucket elevators: Specification, Maximum lifting height (m), Transport capacity (m/h), Bucket pitch (mm), Motor power (kw). Model 160: 28, 3–8, 500, 3–7.5; Model 200: 31.5, 6–15, 500, 3–7.5; Model 250: 30.16, 10–25, 500, 4–11; Model 300: 30.16, 25–35, 500, 5.5–15; Model 350: 31, 19–40, 600, 7.5–18.5; Model 400: 32, 35–50, 600, 7.5–22; Model 450: 32.7, 42–60, 600, 7.5–22. The above values are for reference only