2013年5月29日星期三

Scraper conveyor failure analysis and solutions




Scraper conveyor longwall face is the main transportation equipment, its work properly or not, for the entire coal mine production safety plays a vital role. The scraper chain

scraper conveyor is the main component, is an important traction mechanism, which consists of scraper ring chain, link chain three

Parts, there are statistics show that approximately scraper scraper chain conveyor fault 40% of the total number of failures, therefore, improve the quality of scraper chain

scraper conveyor, prolong life, shaker will help reduce operational accident rate improve the reliability of mining equipment, helping to increase yields face

. Scraper scraper chain conveyor for failure causes and solutions are analyzed and discussed, has a very important practical significance.spiral conveyor
1 fault types and causes
(1) scraper damage
Mostly bent blade damage, excessive wear, a few cracking phenomenon. Its main causes are: laying chute does not meet the design requirements, beyond the requirements of the

bending angle; chute poor bonding at the interface, causing local deformation conveyor chute large lump or waste rock, etc. in operation

Suddenly being squeezed, the blade subject to greater impact; when the adjacent blade spacing exceeds the design requirements, the long-running load on the blade overrun.
(2) on the scraper chain off the sprocket
Scraper chain and sprocket normally not engaged, there called "jump teeth" phenomenon. Its main causes are: head and nose transition groove bending angle is too large; nose slot

plate uneven transition; sprocket badly worn or bite into the debris; linear shaker two chains elastic inconsistent; scraperindustrial conveyor

Severe skew or the spacing is too large.
(3) in the scraper chain coming out of the chute
Its main causes are: scraper conveyor does not meet the design requirements when laying tile laying straight, but convex concave, excessive bending; scraper or chute badly worn,

the blade and chute gap is too large; Coordinate rotation vibration sieve two chains of varying lengths, uneven force; blade deformation is too

Degree bend away from the scraper chain chain shortening; scraper chain pretension is not enough, the shearer cutting machine at the end of the scraper, the scraper chain load

increases, chain link elongation increased at the end of the machine cause heap chain, making the scraper easily disengaged from the chute.
(4) damage to the link chain
In the current domestic ring chain increased reliability in the case, the link chain ring chain fatigue life compared with a big gap, in actual use, the entire link chain became

weaker scraper chain link. It is mainly in the form of damage to the fracture, and its main causes are: long

Under alternating between pulsating loads, well below the breaking force of the water products, the occurrence of fatigue failure; connecting bolt or pin fall off, unable to

replenish, leading to uneven force uniform or inability to force; when used in vertical ring , unilateral severe wear on the teeth, or arc tooth link chain if not more

Change, prone to fracture; card chain, will have a greater dynamic loads and impact loads, combined with scraper chain velocity fluctuations, scraper chain running smoothly so

poor, so that the link chain breakage; Manufacturing Quality poor, not up to standard requirements, low hardness, or appear to be easy to wear

Stress concentration points where fatigue crack, resulting in insufficient strength.
(5) ring-strand breaks
In theory, the use of a variety of scraper conveyor chain ring should be in accordance with standard C-level chain of production, and its breaking load is approximately scraper

can withstand tension nearly 10 times larger safety factor, should not be scission accident, but it and the actual use failure rate greater this

A case does not match, its causes are mainly: manufacturing quality up to standard requirements, material and heat treatment, but off; withstand prolonged alternating pulsating

loads, far below the level of breaking force, the occurrence of fatigue failure, fracture generally chain link arc portion and a straight portion connected

Take place; chain in operation with the chute, sprockets, cargo and other contacts to friction wear, weaken links section, resulting in reduced strength, wear is mainly

manifested in the straight portion of the outer chain ring, circular outer and inner part 3 two parts; chain ring is underground water, corrosion, rust

, Peeling, the cross-section decreases, the intensity decreases; scraper chains to fall into the iron and other occurrence card chain, the chain tension exceeds the allowable

value is pulled off; blade pitch more than twice the required distance when running to the head office is , the chain tension, so that no Bengqi scraper chain, not

Slide the blade slot, but also with the next scraper chain Bengqi with pear head unloading coal board interference occurs card chain, resulting in chain scission; chain

pretension inadequate and too loose, easy to form a heap chain, resulting scraper the tank, the phenomenon occurs card chain; chain tensioner force the Ambassador chain too

tight, increasing the chain's early photos

Force, accelerated wear of the chain and shorten the life of the card in the event there is no cushion to chain; chain in the case of full or overloaded, frequent starting, so

that the chain withstand dynamic tension than the ultimate strength; two chain tightness inconsistent, so that the load is concentrated in the more compact

One chain, thereby exceeding the ultimate strength.

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