Belt Conveyor: 七月 2015

2015年7月21日星期二

Two-way Pull Cord Switch of Belt Conveyor Protection Devices

The two-way cord switch adopts the world’s leading dual bearing transmission structure in order to avoid the friction exists on drive shaft directly when the s pull cord switch is switched on, causing the increasing gap, improper seal or stuck phenomenon, which will prolong the life-span of pull cord switch. Precise painting applied on the surface of two-way pull cord switch of belt conveyor protection devices which is not easily to fall off. The driving shaft is made of stainless steel material with high intensity, the surface of shaft is smooth. The lever is made precisely to avoid the welding. Besides, the bronze cushion is built internally which makes smooth surface of lever and higher intensity. This product has several advantages, which are longer life-span, flexible, practical ,safe and reliable operation, easier maintenance and so on.

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Henan Pingyuan Mining Machinery Co., Ltd is the most professional manufacturer of Belt conveyor, and Vibrating screen, Bucket elevator, Screw conveyor, Scraper conveyor using the world's most advanced technology, we are willing to serve every company to meet your custom needs. Our goal is "be the future global leader of mining machinery industry". Have any questions, please contact us without any hesitation.

Vehicle Type Tensioning Device of Belt Conveyor

Vehicle type tensioning device of the belt conveyor is that the tail wheel is mounted on a moving vehicle. The reversing pulley is connected by wire rope, and it is respectively connected to mobile vehicles and heavy hammer, by the effect of gravity, the hammer will cause automatic tension of conveyor belt. Practice has proved that it is appropriate to take great value of the effective stroke. Vehicle type tensioning device has a wide range of applications, which is not affected by the length of the belt conveyor. The conveyor belt tension can be adjusted automatically, which has simple operation and reliable structure, so the design of tensioning device should give priority to the use of the vehicle type.

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Vertical Type Tensioning Device of Belt Conveyor

Vertical type tensioning device is installed between the driving pulley and tail wheel, it should be closed to the minimum belt tension place (driving pulley). When the rubber belt conveyor runs, the structure drives the conveyor belt passing by 90 degree turnabout pulley, then passing by the 180 degree turnabout pulley, tensioning the rubber belt through the heavy hammer which is hanging on the frame. The effective tensioning travel is same with vehicle type tensioning device.

Vertical type tensioning device is suitable for the situation that is difficult to adopt vehicle type tensioning device. The advantage is that it utilizes the space of belt conveyor length which is easy to arrange. The defect is that if adopts this type of tensioning device, the turnabout pulley quantity will increase, material will be easily to fall into the place between rubber belt and pulley, which speeds the abrasion of rubber belt and pulley surface. Especially when transporting materials is damp or with larger viscosity, the abrasion phenomenon will be more serious.

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Screw Type Tensioning Device of Belt Conveyor

Screw type tensioning device is the main parts of belt conveyor which provides the certain tensioning force for normal operation. Therefore, choosing the appropriate tensioning device is the key to design the belt conveyor, here we will introduce the characteristics and application range of these three kinds of tensioning device.

Screw type tensioning device is installed in the place of tail wheel which can make the tail wheel displacement to tension the conveyor belt by adjusting the screw rod .Generally speaking, the screw type tensioning device is suitable for belt conveyor length less than 60 meters with smaller power. The series of tensioning travel are divided into two types:500mm and 800 mm. The tensioning travel can be calculated on the basis of 1% of the length of the belt conveyor.

screw type tensioning device of belt conveyor

The advantages of screw type tensioning device includes simple and compact structure, small space occupation. The disadvantage is that it can’t adjust the tension automatically and tension degree is not easy to control. Screw tensioning device is not recommended to be used for important belt conveyor equipment.

spiral tensioning device of conveyor belt

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How to Solve the Problem of Conveyor Belt Skid?

The main cause of conveyor belt skid is that the friction between conveyor belt and pulley is not enough, details please see the following three aspects:

1.The running resistance is increased, such as conveyor overloads, conveyor belt is squeezed and stuck on the frame, roller damages, stuff twines, material buries etc. will cause lots of rollers can not rotate well.

Solution: conveyor overload is strictly prohibited, the conveying capacity must be designed within the theoretical range ; Replace the roller which can not rotate flexibly; Fully check the entire transportation process, eliminate the bad affecting factors.

2.The friction coefficient is reduced, for example, the contact area of driving drum and belt enters into water, sundry. Rubber coated surface of driving pulley damages.
Solution: replace the driving pulley and clean the stuff that on the non-working conveyor belt surface.

3.The conveyor belt tension is reduced, for example, if the conveyor belt overload works for a long time, the belt will be deformed and stretched, besides, the tension of take-up device is not enough which will leads the tensile force decreases.

Solution: increase the tensioning stroke according to the working conditions, you can also cut off a piece of conveyor belt to solve the problem when the tension is not enough.

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How to Judge the Failure According to the Noise of Belt Conveyor?

1.When there is severe roller eccentricity

There always occurs abnormal noise with periodic vibration when belt conveyor rollers runs, especially the return roller. The reason is that its length is bigger, weight is heavier and the noise is bigger .There are two main reasons of the noise:

1. the seamless steel tube wall thickness is not even which generates large centrifugal force;

2. the center of two bearing ends hole center and the outer circle center has big deviation which leads to large centrifugal force.

2.When the two axis of coupling are not concentric

The coupling of high speed motor of driving device and reducer or coupling with brake wheel occurs the abnormal noise, along with the vibration same with motor rotation frequency. Please adjust the motor and gearbox position timely in order to avoid fracture of gearbox input shaft.

couping& driving device of belt conveyor

3.Bend pulley and abnormal noise of the driving drum

During operation, the noise of turnabout pulley and driving pulley is small, the bearing usually damages when there is noise, please replace the bearing timely.

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Introduction of Three Types of Belt Conveyor Cleanser

1.P type alloy rubber cleanser

It is installed in the place of head pulley, the installation position of P type alloy rubber cleanser is similar to the spring cleanser, compared with the spring cleanser, it is mainly with the help of rubber elasticity, at the same time the hard alloy scraper cleanser presses close to conveyor belt surface after material separates from the conveyor belt, cleaning the material which is stuck on the conveyor belt.

2. H type alloy rubber cleanser

It is installed in the place of head pulley and close to the conveyor belt, the cleaning principle of H type alloy rubber cleanser and P type alloy rubber cleanser is the same.

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3.hard alloy scraper cleanser

Hard alloy scraper cleanser is installed in the place of head pulley, the material of scraper is hard alloy, it has two types: single piece and double piece. You can adjust the counter weight to change scraper stress to conveyor beltto achieve the effect of cleaning materials.

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Do You Know Why There is Conveyor Belt Deviation Phenomenon?

Belt conveyor is a common conveying equipment widely used for metallurgy, chemical, electric power, coal, mining, port etc. In the process operation, conveyor belt deviation happens a lot. Here PK Machinery will analyze the reason as follows:

1.there is attached object on the surface of pulley or roller .
2.both driving pulley and the turnabout pulley have external surface error in manufacturing .
3.the head driving pulley is not parallel with tail pulley.

4.the diameter of driving pulley and the tail pulley is different.
5.the center line of driving pulley and tail pulley is not vertical to the conveyor center line.

6.the feeding position is not straight.
7.pulley center is not in the center line of conveyor.
8.roller installation is not straight.
9.bad frame rigidity which will easily lead to the deformation.
10.unstaight conveyor belt joint and belt aging metamorphism will cause deviation on both sides.
11.unilateral bearing rotation is not flexible, or it is stained with sundry.
12.abrasion condition on both sides of guide pulley is different .
13.deviation adjusting device damages and doesn’t work well.

14.the pulley wrapped with belt is not parallel with the transmission drum.
15.conveyor belt borders on both sides of the centerline are not overlapped, or conveyor belt edges get worn seriously.
16.feeder, discharger and sweeper have installation error.
17.abrasion condition of pulley two ends is different.
18.conveyor belt take-up device doesn’t have enough tension.
19.the layout of feeding direction and conveyor height is not reasonable.
20.roller support gets worn and deflected seriously.

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How to deal with the feed casting of belt conveyor

It is a common problem that belt conveyor will appear the phenomenon of feed casting. And the reason is multi-aspect.The most important thing is that we should emphasis on its maintenance in daily life.

1.Feed casting in the transferring point. This kind of situation will be happened in the hopper and guide chute.If belt conveyor is overload, it will result in the damage of keep-off rubber apron board. We can slove this promble by controling the conveying capacity and strengthening the maintenance.

2.There is feed casting when concave section of belt conveyor suspends in midair. The reason why concave section of belt conveyor suspends isthat curvature radius is smaller. At this time, the situation that beltconveyor becomes groove will change. Because belt has departured trough roller unit, the groove angle becomes smaller that will result in the phenomenon of feed casting. Therefore, we should adopt the larger curvature radius as far as possible in the design stage to avoid happening this kind of situation.

3.When the belt is off tracking, it will appear the phenomenon of feed casting. The reason is that the height of two edges changes when the belt is running. Thus, one side of belt is high while the other is low. And the material will drop out from the lower side. We can adjust the belt running deviation to solve it.

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The introduction and application of tension device

Belt conveyor is a transport machine that is driven by friction and it can transport materials continuously. Belt conveyor needs tension force in order to ensure the normal and stable operation of conveyor and meet the friction driving force between the driving drum and the belt. It is very important to choose the proper tension device when we design the belt conveyor.

Functions

1.Tension device can make the belt conveyor have enough initial tension force so that can ensure the necessary friction between belt and driving drum.It also can reserve friction to meet the requirements of friction drive of transmission drum.

2.Tension device can ensure the tension force of minimum tension point in order to satisfy the pendulous restriction conditions of conveying belt so that can make sure of the normal running of conveyor.

3.To provide the necessary route for conveyor belt joint.

Detailed rules and regulations of operational approaches

When we turn off belt conveyor, the stored energy of conveying belt will release rapidly; and then it will damage its mechanical components and conveying belt itself, especially in the dip angle of belt conveyorand the tension device. When the belt conveyor brakes suddenly, the speed of driving drum will decrease rapidly and the linear displacement will less than the displacement of upstream drum. This characteristics will decrease the mechanical stress of upstream conveying belt and the deformation of belt will smaller, while the mechanical stress of downstream conveying belt will increase as well as deformation. That is to say,when the speed of transmission drum suddenly reduces, the returning conveying belt under the transmission drum caused by the mechanical stress of belt will be strained while returning conveying belt and upward conveying belt below the transmission drum will be relaxed because of the inertia of mechanical equipment. Thus, tension device of conveying belt should pay much attention to its deformation and brake the displacement of upstream position.

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Modified of UHMWPE

We can improve the process ability and heat resistance of UHMWPE through mixing it with other resin and adding auxiliaries. With higher performance of UHMWPE, we can produceconveyor rollers, belt conveyor in higher technology and quality.

1, Modified of liquidity

(1) Mixing UHMWPE with LCP can improve the liquidity and can use the single screw extrusion machining. The more additive amount of LCP, the better of liquidity of mixture.

(2) Mixing UHMWPE with PE can ensure the good process ability of mixture as the additive volume of PE is below 30%. Besides, it keeps the excellent performance of UHMWPE.

(3) Mixing UHMWPE with PE-WAX, Erythromycin stearate less than 10% and so on.

(4) Add 3-5% layered CADD into UHMWPE, and the melt index can reach 0.2-0.4g/10min.

(5) Add 1% pyrogenic silica into UHMWPE, and the mixture can be nucleating agent of PE to improve the liquidity.

2, Modified of abrasive resistance: Adding the ultrafine molybdenum disulfide, graphite, carbon black, ultrafine glass bead, carbon fiber and PTFE treated by coupling can reduce the friction coefficient and improve abrasive resistance. However, it will improve the friction coefficient to add rubber or PU into UHMWPE.

3, Modified of heat resistance: after treated by plasma crosslinking, the operating temperature of UHMWPE can reach 200℃. And filling inorganic filler treated by coupling in UHMWPE, such as glass fiber, carbon fiber, glass beads, wollastonite, calcium carbonate, talc, mica, graphite, diatomite, copper powder, etc. HDT will improved obviously.

4, Modified of heat conduction: the heat conduction of UHMWPE can be improved by adding copper powder, aluminum powder, lead powder and other metal powder.

5, Modified of mechanics: the strength, hardness and stiffness of UHMWPE can be improved by adding glass fiber, carbon fiber, superfine glass beads, calcium carbonate, kaolin, talc, mica, needle-like wollastonite, 3 oxidation 2 aluminium and silicon dioxide.

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Features and Maintenance of Portable Belt Conveyor

Features:

1.Portable belt conveyor can work in any applicable site , and avoid operating in rainy day.

2.Because of its good performance so that you can directly for loading and unloading car, material handling, etc.

3.Easy to operate, no need for manual duty and start work once boot.This machine is equipped with electric control box which contains a master switch and a lift the switch.

Maintenance:

1.Avoid operating in damp environment and rainy day as much as possible to protect machine body from rust damage.

2.Regular check to ensure smooth running direction, to avoid the unnecessary loss due to conveyor belt running deviation.

3.Regular check the fasteners of machine body to ensure the bolt tension equipment in good condition. Add lubricating oil in time to ensure that the bearing lubrication. Regular check roller and other replacement of damaged parts to ensure the normal use of belt conveyor.

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Reasons of Drifting of Belt Conveyor

As one of the most common conveyors, belt conveyor is widely used in metallurgy, chemical, electricity, coal, mining, port, transportation and so on. In operation of belt conveyor, there is much drifting of the machine. The following is reasons of the phenomenon.

1. There is coal or other attachments in the surface of pulley or idler.

2. There is mistake in the degree of net post manufacture of driving pulley and bend pulley.

3. Driving pulley and bend pulley are not parallel.

4. Diameters of driving pulley and bend pulley are inconsistent.

5. Center line of driving pulley and bend pulley is not vertical with center line of machine body.

6. Feeding position is inappropriate.

7. Center of pulley is not in the center line of the machine.

8. Installation of idler is inappropriate.

9. Stiffness of frame is bad which causes the deformation of the machine.

10. Joint of belt conveyor is inappropriate or the belt conveyor is aging and deterioration.

11. Rotation of unilateral bearing is not flexible.

12. The damage of ware of the two side of driving pulley are inconsistent.

13. The adjusting device is damaged.

14. Girdle pulley in head and bend pulley are not parallel.

15. Center lines in both sides of belt conveyor are not consistent, or the margin of belt is heavily damaged.

16. Installation of feeder, unloader and sweeper is inappropriate.

17. Degrees of ware of two sides of coal unloading pulley are inconsistent.

18. Take-up tension of belt conveyor is not enough.

19. Feeding direction and height arrangement are inappropriate.

20. Support of idler is heavily damaged.

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Troubleshooting of hopper belt slipping

1) Bucket elevator uses the friction between the hopper belt and the head wheel drive shaft to lifting material. If the hopper belt strength is not enough the hopper belt will slip. At this time, you should shut down the machine immediately and adjust the take-up unit to tension the hopper belt. If the take-up unit can’t make the hopper belt fully tension, this shows that the take-up unit work distance is too short, you should re-adjusted it.

The better solution is: open the joint of hopper belt, adjust the take-up unit in on the tail wheel to the highest position, put the hopper belt via head of elevator, threading head wheel and tail wheel and connected tail and head well, then the hopper belt will keep the tension but not fully tension state. In this case adjustment spindle of the take-up unit work distance should not less than 50% of the whole work distance.

2) When bucket elevator is overloading, the resistance torque will be increased and make the hopper belt slipping. In this case, you should reduce the feeding material and try to feeding uniformly. If it didn’t work, then the possible reason is there is too many material piled up in the base or hopper locked by the piled up material. At this time, you should shut down the machine and begin troubleshooting process.

3) If the inner surface of head drive shaft and hopper belt is too smooth, then the friction between them will be reduced, which will caused the hopper belt slipping. In this case, you can spread a thin layer on their inner surface to increase the friction.

4) The bearing of head and tail wheel occurs inefficient rotating will increased resistance torque and result in the hopper belt slipping. At this time, you can open, wash, oiling the bearing or change the bearing.

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How to Solve the Problem of deviation of belt conveyor

Belt deviation of belt conveyor is the most common troubles in operation. Key points to solve the problem are ensuring the precious size in installation and regular maintenance. As various reasons of deviation, we need to solve problems distinctively.

1. Adjust carrying idler group. When belt in middle section is deviation, can adjust the place of carrying idler group. The concrete way is that forward idler group to the side belt biased while other side backward. Move the lower part of idler left when belt running deviation upward when upper part downward.

2. Install spherical idler group. There are many types of spherical idler, such as intermediate shaft type, four link type, vertical roller type, etc. It is reasonable to install spherical idler for shorter belt or two-way runningbelt conveyor because shorter belt conveyor is easy deviation and uneasy to adjust. However, longer belt conveyor may as well not use this way as spherical idler may effect the service life of belt.

3. Adjust the positions of driving roller and bend roller. If belt is running deviation to the right side of driving roller, move bearing at right side forward. And same to the left side. Adjustment method of bend roller is opposite with driving roller. Adjust repeatedly to the ideal position and may well as install accurately before adjust the rollers.

4. Adjust take-up unit. Take-up unit adjustment is the very important part of deviation adjustment of belt conveyor. Two bend rollers at the upper side of heavy hammer take-up should perpendicular to belt length direction and vertical gravity to ensure its shaft center line horizontal. When use screw take-up or hydrocylinder take-up, two bearings of take-up roller should translate at the same time to ensure roller axis is vertical with longitudinal direction of belt conveyor.

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Troubleshooting of Mining Belt Conveyor

As the development of the conveying technology, belt conveyor used for mining industry also changed rapidly, adding many new functions. These new functions provided convenience for the user's operation and maintenance. Mining industry are mostly make multiple machineries work together to complete the handing task. If improper operation or material blocking caused the conveyor stop working, the motor will prone to be overloading and making abnormal sound. At this time we should shut down the conveyor immediately and examine the conveyor to find out the failure reason.

Because mining industry has more complex situation the machinery will be prone to cause problem, if we can’t find out the problem promptly then will bring a greater loss, so Mining Belt Conveyor should be installed a sensor in the right place. When a trouble happens on Mining Belt Conveyor, such as motor burning, transmission part damaged, belt or chain fracture, belt slipping,

we should design and installed some sensor or control switch with the shut down and control function, so that when trouble happens the sensor switch will give out the signal of shut down the conveyor automatically and also give out alarm. It not only reduces the damage caused by the trouble but also find out the trouble part promptly save the maintenance man lots of time.

Here we want to emphasis the take-up device of the belt conveyor. It is well known to us that the operation of thebelt conveyor should maintain proper tension, if the belt become sag and can’t meet the required tension, the belt will be prone to slipping on the transmission pulley. Providing that we can’t adjust the belt promptly, it not only affects the conveying efficiency but shorten the useful life of the belt. The take-up device of the belt is designed to make the belt up to the required tension to avoid belt slipping on the drive pulley and guarantee the deflection between idlers in the specified range. The new belt and the belt using after a certain time is different in the length and tension, so we should adjust the take-up device promptly.

Mining Belt Conveyor is mostly work with multiple machineries, so the control and operation of the machinery are usually adopt intelligent controlling and remote monitoring technologies. Thus, when the trouble happens on the machinery, the automatic alarm device on the conveyor will give out signal to the operator promptly, then the operator can use the feedback information to find the trouble part directly and begin repair the trouble part. It not only saving the operator’s time of finding the trouble but also minimize the damage of the users caused by the conveyor shut down.

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