Overview: With the development of the national economy, the volume of large-scale dry bulk cargoes such as coal, ore, sand, bulk grain, and chemical fertilizers in water transportation has increased year by year. Develop in the direction of low energy consumption. Port transportation machinery plays a key role in the specialization of bulk cargo terminals. Belt conveyors, as one of the important components of port transportation machinery, have laid the foundation for the reliable, efficient, energy-saving and economic operation of port transportation machinery. Combined with the port transportation machinery process requirements and characteristics, the design points of the port belt conveyor are emphasized and the application is briefly listed.
(I) Port transportation composition and typical technology:
Port transportation machinery mainly includes three categories of continuous transportation machinery, port loading and unloading machinery, and auxiliary equipment. Among them, continuous conveyors are mainly belt conveyors;
Loading and unloading machinery mainly includes various ship unloaders, ship loaders, unloaders, dumpers, stackers and reclaimers, etc .;
Auxiliary equipment mainly includes storage, feeder, metering device, iron removing device, various protection devices, etc.
According to the different uses of the port, based on the belt conveyor, different loading and unloading machinery can be configured to build a fairly capable import and export terminal loading and unloading conveyor system. A system generally has several processes. The following:
1) Unloading (ship) ----- stacking process;
2) Reclaiming-loading (vehicle) process;
3) Reclaiming-conveying process to the using unit;
4) Unloading (ship) --- loading (shipping) straight out process;
5 unloading (ship) --- direct delivery process to the user;
(2) General requirements for the design of the port belt conveyor:
(1) Determine a reasonable reproduction method, and put forward the requirements for the feeding device and the discharging device;
(2) The relationship between the belt conveyors of the conveyor system should be straightened out. According to the starting sequence, the receiving conveyor moves first, and the stopping sequence is the feeding conveyor stops first. When the parameters of the conveyor are different, the relationship between the starting and stopping time is required through this relationship;
(3) When the above requirements of starting and stopping sequence cannot be met, it is necessary to consider adding a buffer silo between the conveyors to improve the adaptability of the system and the operating rate of the system;
4 (4) Environmental protection requirements. For heavy dust, consider using closed transportation or installing necessary dust removal and dust reduction equipment;
5 (5) Standardization and generalization of parts and components and the possibility of supply of wearing parts;
6 (6) Select a conveyor suitable for the inclination angle of the process. According to the characteristics of the material and the working environment, the allowable inclination angle of the conveyor is 15 °, and the lower angle is 10 °.
(7) The sag of the adhesive tape between adjacent roller groups must not exceed 1%;
(8) When the belt conveyor is braked, the maximum working tension should not exceed 1.5 times the working tension during normal operation;
9 (9) The design of the curvature radius of the concave arc section of the belt conveyor should be such that the tape does not leave the idler and does not cause the phenomenon of floating when starting at no load;
(3) Design content and basis of port belt conveyor:
The design content mainly includes conventional belt conveyor design, dynamic design, resonance avoidance design, component design, electrical and control system design, etc. Before the system design, the requirements for the equipment should be fully understood, the main basis is the conveying capacity; It can be given directly when it is uniform. Generally, it should be designed and calculated according to the 10% overload capacity, unless otherwise agreed. The detailed dimensions of the transmission line; mainly including the maximum length, inclination, length and height of connection, and connection dimensions. Material properties; main parameters include bulk density, repose angle, particle size and maximum block size, material humidity, abrasion, cohesiveness and friction coefficient. Working conditions and environmental conditions; ambient temperature, place of use, environmental requirements, etc. Feeding and unloading methods, running time, working days, service life and other requirements. According to the design requirements, we must carefully weigh and select the maximum sag, simulated frictional resistance coefficient, friction coefficient of conveyor belt and roller, and safety coefficient of conveyor belt. The machine system has parameters that have a great influence on stable, safe and efficient operation.
四 (4) Port belt conveyor component configuration and selection:
(1) Reasonable arrangement and configuration of the driving part
A. Arrangement of driving device:
The driving device is generally not arranged in the transfer machine room but on the ground to reduce the specifications of the machine room. At the same time, the parallel shaft type is preferred for the reducer, which saves system infrastructure costs.
B. Configuration of the drive unit:
Following the principles of reliability, high efficiency, economy, energy saving, and convenient maintenance, the port belt conveyor preferentially chooses the ordinary low pressure (or high pressure) hydraulic coupling drive method. The general principle is to divide according to the motor driving power and the captain. When the motor power N≤150KW, the short-distance tape machine uses the ordinary torque-limiting fluid coupling. When 150 <N≤300KW, the medium-long distance tape machine uses the extended auxiliary cavity moment-limiting fluid coupling. When the motor power N> 300KW, the long-distance belt conveyor selects the extended auxiliary cavity and side auxiliary cavity moment-limiting hydraulic couplings to further extend the startup time, thereby obtaining a more ideal startup curve.
For long-distance (L> 1000m), large-capacity port belt conveyors, priority can be given to variable frequency speed regulation or other soft drive methods. Among them, there are more frequency conversion speed control drive methods, mainly because frequency conversion speed control has the following advantages:
1. The AC variable frequency speed regulating device has the characteristics of wide speed range, reliable control, and obvious energy saving effect. It is easy to realize the automatic tracking of the braking speed curve, and it can provide ideal controllable starting / braking performance.
2. The conveyor can be controlled to start and brake according to the set “S” -shaped speed curve to meet the requirements of dynamic stability and reliability of the whole machine.
3. It can achieve power balance between multiple drive motors with high accuracy.
4. It can meet the requirements of frequent start and stop of the port transportation system.
5. The frequency conversion speed regulation drive device can also provide low-speed belt inspection speed, which is convenient for maintenance and repair.
For high-power belt conveyors, double-drum multi-motor drive should be used to reduce the maximum tension of the system. Therefore, under the premise of ensuring safety, the selection of the tape model can be reduced, and the equipment procurement cost can be saved.
c. Selection of simulated friction coefficient and selection of motor surplus coefficient:
During the calculation of the driving power, the reasonable selection of the simulated friction coefficient and the motor reserve coefficient has a great impact on the calculation results. Select a suitable coefficient to ensure the smooth operation of the conveyor system, while meeting the requirements of energy saving and consumption reduction. Under the premise of providing high-quality products and good installation and construction conditions, and under conditions where the working environment is not particularly harsh, the recommended value of the comprehensive friction coefficient is:
Conveyed material is coal: simulated friction coefficient: f = 0.020 ~ 0.022, conveyed material is ore: simulated friction coefficient: f = 0.022 ~ 0.025. The motor surplus coefficient can take K = 1.05, which must be verified by calculating the additional power of the conveyor at full load to ensure that the final installed capacity can ensure a smooth start at full load.
(2) Support roller calculation selection and configuration:
a. The selection of the supporting rollers mainly considers the carrying capacity and service life of the supporting rollers, and comprehensively considers the following factors: the size and characteristics of the load, the width and running speed of the conveyor belt, the operating conditions, the working system of the conveyor, and the Characteristics, roller bearing life, roller seal structure, lubrication conditions, maintenance system, etc., the selection of roller diameter should ensure that the roller speed is controlled within 550r / min.
B. The supporting rollers in the port section of the port belt conveyor are generally arranged in a 1: 1 slotted roller group and a trough forward inclined roller group, and the interval between the rollers is taken as 1.2m or 1m according to the density of the conveyed material and the volume of the transported roller. The pitch of the convex arc segment is 1/2 of the normal pitch, and the pitch of the buffer roller at the blanking point is 1/3 of the normal pitch.
C. Set the transition idler group at the head and tail so that the tape can be grooved smoothly. The minimum transition distance at the head should not be less than 2.6 times the bandwidth, and the transition distance at the tail should not be less than the normal idler distance. The return section should be configured according to the parallel idler group and the V-shaped idler group (or forward leaning) according to 2: 1, and the interval between the returning idler rollers is generally taken to be 2.4 to 3m. Near the head, the return section should be set with 7 comb-shaped rollers. The return section is changed to the drum to arrange 3 sets of spiral cleaning rollers (generally referred to as the bridge surface). The return section is matched with an anti-V-shaped roller group to prevent deviation. 50m layout 1 group. Among them, special attention should be paid to the trough-shaped idler roller set plus the two-way reversible upward self-aligning idler roller set and the parallel lower idler or V-shaped idler plus the two-way reversible downward self-aligning idler roller set on the two-way running conveyor.
(3) Roller structure and process requirements:
The drum shaft should be high-quality forged steel, and the drum wall thickness should not be less than the standard requirements and should be thickened accordingly. The drum barrel adopts a cast welding structure, and the hub and the axle are connected by an expansion sleeve. The welding between the hub and the flange must be continuous welding with full penetration. For the roller of the cast-welded structure, the material of the cast-welding disk is cast steel, and the welding method of the cylinder is CO2 gas shielded welding. The split bearing seat is preferred. The thickness of the casting rubber of the transmission roller and the redirecting roller should be thickened based on the standard.
(4) Design and stroke selection of the tensioning device:
The tightening forms of port belt conveyors are mainly vertical hammer tightening, heavy hammer car tightening, and hydraulic tightening. When designing the tensioning stroke, the elongation of the tape itself and the necessary installation margin should be considered. The recommended length of the tensioning stroke when using steel wire core tape is shown in the table below:
Horizontal length (m) Effective tightening stroke (m) Remarks
L≤300 0.005L + 1.5B B is the bandwidth
300 ＜ L≤600 0.0045L + 1.0B B is the bandwidth
L ＞ 600 0.004L + 1.0B B is the bandwidth
Horizontal length (m)
Effective tightening stroke (m)
B is the bandwidth
B is the bandwidth
B is the bandwidth
(5) Design of unloading and reprinting system:
A. The unloading and reloading system mainly includes a head hopper, a three-way distributor, a blanking slide tube, a buffer centering device, a material guide groove, and the like.
b. The unloading and transferring system should be designed according to the maximum flow rate and block size of the material to ensure that the chute is not blocked under any conditions; the chute section is not less than 4 times the material section when the maximum flow rate is passed, and the chute section is the smallest. The size should not be less than the maximum size of the three largest block superpositions on the conveyed material, and the chute inclination angle is not less than 60 degrees.
C. Inspect the door at the necessary position of the unloading and reloading system, and seal the soft rubber plate at the flange joint to prevent dust and dust.
d. The three-way distributor must have a heavy-load switching function, and its structure can withstand the long-term impact of the maximum flow and the largest block material. The turning surface of the conversion baffle must be isolated from the material to prevent the baffle from jamming and ensure that the baffle must not be blocked in winter. Freeze with chute. The torque of the electric (hydraulic) push rod of the baffle should be greater than 2 times the calculated torque.
e. The buffer centering device is arranged between the lower part of the chute and the guide belt of the lower belt conveyor. It should be inclined in line with the conveying direction of the lower belt. It has the buffer and prevents the impact and damage caused by the high drop material to the lower belt conveyor. With the function of returning materials.
f. The length of the guide trough should generally not be less than 5 times the bandwidth. There should be enough space inside the guide trough to allow the material to pass through. The height of the guide trough should not be less than the maximum size of the maximum stacking of 3 blocks. Conveyor belts can be sealed with anti-overflow skirts or can be sealed with a whole wear-resistant rubber sheet. At the same time, in order to reduce abrasion and running resistance, the guide groove is generally designed as an X-shaped section.
g. The lifting guide is mainly used in the case of multi-point receiving and penetrating conveying the receiving point. When receiving at this point, lower the side plate. When not receiving the point, lift the side plate to lift. The height is not less than 200mm, so as not to affect the passage of the rear material.
H. Wear-resistant liners are mainly used for the erosion and abrasion of materials in the unloading and reloading system. Common liner materials are: 16Mn, wear-resistant cast iron, high chromium steel, dual alloy welding liner, stainless steel, etc. The size of the liner should not be too large, and the weight should not exceed 25Kg for easy replacement.
(V) Safety protection configuration of port belt conveyor:
Port belt conveyors are located at the seaside, and there are often strong storms. The conveyor must have measures to prevent typhoons from overturning the conveyor belt. The stacking and reclaiming conveyors in the yard and the loading and unloading ship conveyors on the dock must be equipped with windproof chains and Windbreaker. Both are set at 25m. The windproof chain is placed in the chain boxes on both sides of the intermediate frame when it is not working, and it is placed under the conveyor belt when it is not working. At the same time, the harbor belt conveyor itself should be strictly protected, and the main protection personnel can reach the rotating or moving equipment; protect all the cut-off ends; protect all moving parts within the "reasonable" extension; on the workbench, work place, passage And so on to provide strong fences.
(6) Application of Port Belt Conveyor:
Since 2002, it has been used in Huangpi Port, Lianyungang Port, Tianjin Nanjiang Port, Caofeidian, Luoyuan Bay Terminal, Kemen Storage and Transportation Terminal, Zhejiang Zhoushan Terminal, Zhuhai Gaolan Port, Dongwu Terminal, Jiangyin Terminal, and Meizhou Bay Terminal. , Huaneng Caofeidian Port Coal Terminal, etc., with a bandwidth of 2200mm, a maximum capacity of 9000t / h, and a maximum belt speed of 6.1m / s.
Concluding remarks: With the construction, expansion and transformation of large-scale ports, as an important part of port transportation machinery, belt conveyors will have more and more application space, and the design and application of port belt conveyors will continue to deepen and Improvement will also produce more and better economic and social benefits.