Chain Jump Treatment of Buried Chain Scraper Conveyor

When buried scraper conveyor chain jumping failure occurs, it is rarely happens that the chains of both sides are out of sprocket. Generally, single side chain sprockets meshing point will cause both sides chain dislocation and lead the scraper chain in the tilt state of operation. At this moment, stop and repair the machine in time will bring it back to normal running. However, if the failure is not found promptly, more and more serious dislocation could cause chain breaking, cast stone runnel box or chain way damage, and even burn the motor and turn over the base, thus extend the harm of jump chain failure.

The most common issue in the operation of buried scraper conveyor is chain jump and often occurs at the head and tail. While the causes are complicated, such as uneven lining slot box, partly cast slab laying off, gaps at chain way and some other reasons. After long time running, the head gear tooth and tail groove wear is also a factor causing this problem. In addition, when the large bulk materials are conveying, they might enter into the sprocket meshing point which can also cause chain jump.

Feeding Material in Proper Order of Buried Scraper Conveyor

Equipment failure happens when improper operation made in the running process of buried chain scraper conveyor. Please pay attention to the the material feeding sequence.

During material conveying, turning on the device at the first place and opening feed inlet afterwards. In this case, scraper conveyor would not be filled with material avoiding unnecessary losses because of overload motor. When material conveying finished, turn off the slide damperor or the power of the discharger firstly, stop material feeding and turnoff squeegee machine after clean up the material in the conveyor chamber. It will prevent the material accumulation in the equipment avoiding material moisture and agglomeration.

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How to Resolve Chain Deviation of Buried Scraper Conveyor

1. Check installation quality and take measures to correct mounting dimensions.

1) Check and adjust the flange connections between conveyor casings, make sure the connections are smooth and tightly sealed. 

2) Adjust the clearance between chain and conveyor trough. The appropriate clearance value will guarantee the conveyor to operate normally, reduce energy consumption, extend the service life of chain scraper & conveyor trough, and improve transport efficiency. 

3) Check and adjust the surface flatness of guide rail. The joints between guide rails should be smooth.

4) Check and adjust head and tail pulleys, which should be on one center line and correct meshing.

5) Correct and replace the deformed scrapers.

6) Repair and replace the worn-out guide rails.

7) Adjust the tension device, make sure the elastic of chain & scraper is moderate, and the tensile force of left and right sides are the same. 

2. Adjust material drop point.
Material impact is one of important factors that cause chain deviation. The solution is to install a retaining plate at the inlet. In this case, the material will fall in the middle position of scraper & chain to make sure the chain will be uniformly forced, so as to reduce chain deviation. 

3. Install baffle plates on both sides of the chains to prevent deviation phenomenon. 

Difference between forging and casting of scraper chain machining process

Forging and casting is commonly used in the mechanical processing of scraper chain, but do you know the differences? Today, PK Machinery will introduce it in details.
Forging is a processing method which uses the forging machinery occurs pressure to metal blank, make it produce plastic deformation to obtain a certain mechanical properties, a certain shape and dimension.
Casting is the process thatmakes the metal melt into a certain requirements of liquid and pour into the mold, after cooling, solidification, and cleaning the whole process to obtainwith a predetermined shape, size and performance of the casting (parts or blanks).
Generally forging chain mechanical properties are generally better than the same kind of casting chain, but the cost is higher. Although the cost of casting is low, but the production needs more materials and equipment, it will produce dust, harmful gases and noise which will pollute the environment, so we will choose forging chain as the traction component of scraper conveyor in most cases.

How to Choose the Scraper and Chain of Buried Scraper Conveyor? (II)

1. Selection of  Scraper Conveyors Chain
On the basis of meeting the adaptability to material, the chain should be selected reasonably according to maximum working load.
1) Bush roller chain should not be used for dust conveying, and should be first selected to transport the material which is easy to float chain. But in general, die forging chain is used as the first choose.
2) Base on the assurance of maximum chain working load, in order to maximize its carrying capacity,
it is best to use the chains which allowable load is close to maximum working load.
3) On the condition of meeting strength requirement, it should be try to reduce chain weight.
4) Different kinds of chains are used for different arrangement form.
MS / MC / MG buried scraper conveyors: three types of chains can be used, bush roller chain, die forging chain and double chain.
MZ / MP buried scraper conveyors: die forging chain
MK / ML buried scraper conveyors: die forging chain and double chain

2. Selection of Chain Pitch

The selection principle is to minimize the maximum dynamical load and up & down movement speed of chains. If the chain shake is too big, it will destroy normal material transportation, especially vertical conveying. And big dynamical load will lead to the increase of chain weight or decrease of its service life. 
3. Selection of Scraper Pitch
The scraper pitch can be determined according to the conveyor trough width, but it must be adaptable to chain pitch. If the scraper pitch is too big, it can lead to relative slippage between various material layers in conveyor trough, so as to increase energy consumption and even destroy normal material transportation. On the contrary, too small scraper pitch will increase the traction weight and energy consumption. 
The scraper pitch generally equals to chain pitch. When the load is small, the scraper pitch can be chosen the twice of chain pitch. Meanwhile the material features should be taken into consideration, for example, when conveying viscous material, the manufacturer can install a special form scraper, to remove the sticking of material inside conveyor trough, and prevent most viscous material bonded on the inner wall of conveyor trough.

Long life chain trough scraper conveyor

1. Scraper chain conveyor should be no-load running for a certain time when start the equipment every time, Then feed the material after the equipment working normally. We should keep feeding the material evenly, sudden feeding or over-load running is not allowed.
2. Should not stop the machine with load if there is no special condition.
Generally,we should stop the equipment when the material in the trough were discharged completely after we stop feeding the material.
3. If the whole production line is consist of sets of conveyor, we should
start the last set first when start the whole system, then start the others one by one . The order will be opposite when stops.

4. Operators should check the spare parts of the conveyor timely, especially the conveyor chain and driven device.
5. During operating, we should protect the conveyor from the iron, large hard objects and impurities to avoid damage the equipment.
6. Should keep all the bearing and driven device lubricated well. However, should not lubricate the conveyor chain, support guide rail, head wheel and tail wheel etc.
7. In general, the buried scraper conveyor should be minor repair every half year, medium repair every year and overhaul every three years. For overhaul the buried scraper conveyor, we should remove and clean all the spare part, replace all the wear part. For the motor and reducer, should be maintained and repaired according to their technical requirement.

Selection principles of scraper chain

Scraper chain selection is mainly for the rational use of its structural type, chain pitch, blade pitch, scraper chain of materials and the like. In addition should be selected when the production capacity to meet the requirements, particular attention should scraper chain adaptability of the materials.

Scraper type often determines buried scraper conveyor conveying effect. The screed right choices, be satisfied with the delivery results; If you choose blade incorrectly can cause deterioration of conveying effect, can not even transport.
Type scraper blade choice is mainly to meet the conditions under the adaptability of materials, as far as possible to select the type of structure is relatively simple principle. Specifically selected, can be selected according to the material properties of the material viscosity, suspension and liquidity, machine groove width, conveyor layout and so on.

• pairs of conveying materials with better performance, giving priority to the use of a simple shape of the blade type, such as T-type, V-type, U-type; internal friction coefficient is small, the suspension is strong, mobility of materials should be used complex shape The blade, such as H-type.
• After delivery viscous or sticky larger absorbent materials, should adopt simple shape type, such as T-type, V-type, U-type, in order to reduce the material to adhere to the scraper, easy unloading and cleaning.
• delivery pressure knot strong chain or easily float material can be welded to prevent floating chain blade tilt.
• Machine groove width is smaller, the blade should use simple shapes. When transporting a bulk larger machine slot high density materials, in order to increase the rigidity of the blade, it can be used with a brace of O-type guillotine plate.
• buried scraper conveyor arranged horizontally (MS type), generally choose T, U-shaped or V-shaped blade; a vertical arrangement (MC type), generally V-shaped and U-selectable blade and are arranged for outward; Z-type arrangement (MA type), optional V-shaped blade, as introverted layout; buckle type arrangement (MK type), select V-shaped blade, as outgoing layout; flat annular arrangement (MP type), only You can choose L-shaped, outward arrangement; facade annular arrangement (ML type), optional V-shaped blade, as outgoing layout.