The bucket elevator is the main vertical conveying equipment of the cement plant. It is characterized by large lifting capacity and high lifting height. The general lifting height is 20-40m, low energy consumption, simple operation and maintenance, long service life, small floor space and operation. The sealing performance is good.
The hopper is driven by a chain or tape to circulate inside the casing. When the hopper is running upwards, the material is lifted to the top of the casing. When the hopper is rotated, the material is discharged from the discharge port. The bucket elevator is divided into a hopper type, which can be divided into a belt type, a chain type, a plate chain type and a hook head gravity. Four types. At present, large-scale cement plants at home and abroad use plate chain bucket elevators.
Subject to larger material shipments.
The hoist installed in the workshop, the machine base is mostly located in the pit below 0.00 in the workshop, and the hoist installed outside the workshop. The height of the base is 0.00% of the workshop.
1. Basic scribe line According to the position of the equipment on the drawing and referring to the distance of the equipment connected to it, the vertical and horizontal center line of the hoist base is drawn, and the error shall not exceed 10 mm. Then, at the anchor bolt hole, use the seat slab method to place the flat horn so that the elevation error of each group of horns should not exceed 1mm, and the level error should not exceed 0.1/1000.
2. The casing of the casing is welded into a rectangular box with 2- 5mm steel plate. In order to strengthen the rigidity of the casing, 2-3 ribs are rolled on the wide surface of the rectangle, and each section is about 2 to 2.5 m long. The upper and lower ends are welded to the flange interface by angle steel. In the section of the base and the middle section, there are removable side panels on the wide side. After installation, the removable side panels are tightened with bolts.
There are generally three ways to install a chassis:
(1) Overall installation method:
When the bucket elevator is installed outside the workshop, there is a sufficient site at the installation site, and the overall lifting method of the casing can be adopted. After lifting, install the machine head.
Place the base on one side of the foundation, level the floor with a sleeper, set the case on the sleeper, and then hang one or two sets of pulleys on the workbench to lift the case. It can also be lifted by the crane as a whole. After the casing is erected, it is corrected in time, and then the casing is welded together with the support attached to the structure of the workshop before lifting. Then lift the upper head to the casing.
When using the integral lifting method, it is necessary to check the rigidity of the casing when it is lifted. When the stiffness is not enough, reinforcement measures should be taken to avoid permanent deformation of the casing.
(2) Flip method:
The hoist in the workshop is mostly installed by flip-chip method. First check the upper structure of the workshop and check whether there is a lifting ring at the middle point of the hoist. There is no lifting ring. If the structural hanging pulley is used, the strength of the structure should be calculated, and the weight of all the clamshells can be withstood. If it cannot be tolerated, the two sets of wooden and hanging pulleys are used for lifting.
Hang the machine base in the pit, after looking for it, set up the platform on the pit, then fix the upper flange of the upper section of the casing, bolt a slot steel, install the pulley on the channel ring, and lift this section Start. Then push the second section of the casing onto the platform, bolt the first section and the second section of the casing, and then lift the first and second casings to advance the third and fourth sections until the last one. The joint is connected to the base. After all lifting, carry out the search. The head assembly is hoisted from the workshop outside the crane into the workshop and connected to the casing.
(3) Formal method:
Firstly, the number of casings required for each floor between the slabs is hoisted from the hoisting holes or outside the workshop by cranes or winches on the floors of the slabs, and they are arranged in the order of installation.
Hang the base in the pit and press the base line to position the base. Then install from the base to the next section, until all the cabinets are installed, correct, and then install the machine head.
The installation quality of the bucket elevator is better sealed. Therefore, a rubber asbestos mat should be placed at the interface of the two flanges of the casing. At the interface of the imported bucket elevator, in addition to the rubber asbestos mat, it is required to apply a sealant sealant to ensure the sealing performance of the bucket elevator.
The installation accuracy of the bucket elevator is the accuracy of the installation of the base, which affects the overall accuracy. When the base is installed, the center line of the casing is coincident with the center line of the foundation, and the distance between the two corresponding sides to the center line is equal. The horizontal level is determined by the frame level and the ruler, and then fixed by the anchor bolts.
After the bucket elevator head is hoisted, it is necessary to carry out the search. The overall verticality of the casing is checked. When inspecting, three pendants are hung on the outside of the casing. The full vertical tolerance allows for an error of no more than 1/1000. Measured at the interface flange. The allowable error of a, b, c at the cross section of each flange of the casing is not more than Â±6mm.
The cross section of the casing is distorted and can be adjusted with a jack.
3. Installation of transmission sprocket and reversing sprocket Two sprocket wheels or rollers are installed in the casing of the machine head, which are supported by the outer bearing housing of the casing. One end of the sprocket shaft is coupled with a reducer and an electric motor by an elastic coupling. The sprocket and shaft of the nose are usually assembled into a component at the manufacturing facility and shipped to the installation site. The motor and reducer are driven by a V-belt. A reverse stop structure is installed inside the reducer V-belt. When the belt is running, the operation is suddenly stopped for some reason, and the backstop structure can prevent the hoist from reversing.
The base also has two reversing sprocket wheels in the housing. The sprocket bearing is in the shape of a square. The sprocket is adjusted along the sliding path outside the casing to adjust the tightness of the chain. There is an inspection port at the base and it is sealed with a cover during operation.
After the shell is inspected, the drive wheel and the reversing sprocket are mounted on the respective bearings. Perform sprocket positioning measurement (Fig. 12-38). At the equidistance of the side of the drive sprocket, lift the two lines to the lower part of the driven sprocket so that a=a`, b=b`, c=c`,d =d`, the error is not more than 2mm. Then use the frame level to measure the level of the drive sprocket shaft and the reversing sprocket shaft. The allowable error of the drive sprocket shaft does not exceed D/1000. The allowable error of the redirection sprocket shaft does not exceed D`/500 (D and D` respectively For transmission and redirection sprocket outer diameter).
If the error does not meet the requirements, add a horn and adjust the position at the drive sprocket bearing.
4. Installation of chain and bucket When the drive sprocket and the reversing sprocket are searched, the chain and chain bucket can be installed. The installation of chains and buckets generally begins with the movable side panels (or inspection doors) of the enclosure. Before pairing the chain, first hang the pulley above the drive sprocket, put on the wire rope, and lift it with a winch. It is connected by a channel steel cross arm between the spans of the two chains. Both ends of the cross arm are fixed by bolts and chains. When the chain is placed on the drive sprocket, the chain should be fixed with iron bars. At this time, the hoisting position is changed, and the hoist and the wire rope are placed on the other side of the reversing sprocket, and pulled up from the top to the bottom, and then the installation is continued. When the chain is completely hoisted, the ends of the chain should be bolted with steel wires, and the chain should be connected by reversing.
There are currently two ways to install the chain bucket. One is to install the chain first, and then install the chain bucket. This method is generally used for the installation of small bucket elevators because of its light weight and low height. The other is a combination installation. Install the chain bucket on the chain beforehand and hoist it once. This method is generally used for the installation of large bucket elevators because the large bucket elevator chain is wide, heavy and high.
When installing the chain bucket, it is necessary to pay attention to the discharge direction of the bucket, and it is absolutely impossible to make a mistake.
On the other hand, it must be noted that falling due to its own weight is dangerous.
5. Installation of the upper cover of the casing After the inspection of each part has been met, the upper casing is installed. To add a gasket to the joint, tighten the coupling bolt to keep it tight and prevent ash leakage.
6. Transmission installation According to the construction drawing requirements, first install the reducer and then install the motor. The center of the output shaft of the reducer should be on the same center line as the center of the bucket hoist drive sprocket shaft, and the error should not exceed 0.1 mm.
7. Installation of the fixed frame After the installation of the bucket elevator, install the fixing frame at each floor to keep the lifting machine stable. When installing the mounting bracket, be careful not to solder the bucket elevator casing to the mounting bracket because the hoist will heat up during normal operation and raise the temperature of the cabinet. If the casing and the holder are welded to each other, the temperature will rise, the hoist will be bent, or the holder will be cracked, which has occurred many times during construction.
8. Adjusting the trial run of the bucket elevator (1) Check before the test run:
a. Check the bite of the drive sprocket and the chain;
b. Whether there is oil injection at each lubrication point;
c. Confirm the anti-reverse device.
(2) Requirements for commissioning:
a, no load test run 4h, no scraping wall, scraping bottom phenomenon; should not vibrate, no noise.
b. Each bearing is tested once every 20 minutes, and the temperature should not exceed 70 Â°C.
c. At the interface of the casing, the access door is inspected, and the inspection hole is tight and airtight.
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