As the project scale continuously extends, the technical requirements on projects are strict. So many EPC companies also face more risks. Although EPC companies try their best to complete the projects, the result is worse than the expect. At the same time, they also lose many other developing opportunities. How to avoid the risks is the important problem to be considered for many EPC companies, especially for contracting stacker reclaimer, belt conveyor, and magnetic separator in cement industry.
Most people think that the EPC project's total price is fixed. If the bidding price is too high, it is easy to lose. And they also abandon the right of changing contract. In fact, the fixed total price is relative. In generally, the EPC price is the product of simulate workload and unit price. The unit price is fixed. And the total price is changed along with the workload. If the owner change some functions such as changing working range and raising special requirements on some functional equipment, the total price of contract will change. Besides, the work-period is long, which makes the price be influenced by price fluctuation. In this way, the cost will be influenced. So we should not give up the clause of changing price. We should fully consider the requirements of the owner and other factors to give explanations in the contract.
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Apron feeder is widely applied in the industries of mining, metallurgy, building materials, chemical, coal and etc. Heavy duty apron feeder could convey materials with different granularity and bulk density to various receiving devices. Heavy duty apron feeder has two installation ways, horizontal installation and inclined mounting (the max upward inclination is 25 degrees). The equipment uses variable frequency motor and hydraulic motor speed regulation, which could carry out control interlock with receiving devices and insure maximum efficiency of receiving devices. It has many advantages such as simple structure, easy operating, convenient maintenance, saving labor and durable service. Heavy duty apron feeder mainly consists of six parts including driving device, transmission shaft, straining shaft, link plate, various track roller, and frame. Apron feeder has two driving types including mechanical driving and hydraulic motor driving. Driving device adopts self-developed DT series of reducer or Hagglund hydraulic motor. Mechanical driving adopts orthogonal combined type design. The installation adopts suspension type, in which mechanical driving device is nested in main axle through the hollow shaft of reducer. The mechanical driving device and main axle are connected tightly to realize overload protection by fastening locking disc. Heavy-duty apron feeder has advantages of small installation error, easy maintenance and saving labor. The keyless connection is applied in connecting main axle, sprocket and bearing housing, which makes installation and disassembly easy. The teeth of sprocket is handled through quenching process, which makes sprocket have many advantages such as good wear-resistance, better impact resistance and service period reaching more than 10 years. Recently, the automated warehouse is equipped with stacker reclaimer, screw conveyor, apron feeder, robot and other automatic equipment. We should also check the related conveyor components to guarantee the normal operation of the whole conveying system. The stacker reclaimer is widely used in wharf, power plant, metallurgy and other industries. Bucket wheel stacker reclaimer's bucket would craze with high rate of wear, which reduces the service life of bucket. The cracking of bucket makes the production in passive situation. The damage of bucket has following forms: The corner where the tooth is installed cracks. This is the common fault for the damage of bucket. If the equipment continues to operate, the cracking will be more serious, which would result in the unbalance and transformation of bucket disc. The right method is to stop the operation and renew bucket. There is cracking on the chain corner. This is one of the common faults of bucket. If the stacker reclaimer continues to operate, the bucket lip cracking would occur. All we need to do is to stop the operation and renew the damage part. The teeth and lip of bucket are easy to wear. The teeth and lip of bucket are the most important parts of the bucket, which bears the impact of materials. The teeth abrasion of bucket is large. When the teeth wears to some degree, the abrasion of bucket lip would be rapidly increased. The steel plate of bucket lip becomes thin, which results in the lower bearing load. According to the above faults, we could arrange daily checking and walkaround inspection to prevent the sudden stopping of the stacker reclaimer. Recently, the automated warehouse is equipped with reclaimer, pipe conveyor, apron feeder, robot and other automatic equipment. We should also check the related conveyor components to guarantee the normal operation of the whole conveying system. Technological Process Influencing the strong and weak magnetic field of magnetic separator3/23/2017 The magnetic field of magnetic separator has strong and weak type. The magnetic separator with weak magnetic field mainly adopts open magnetic system. And the magnetic separator with strong magnetic field mainly adopts closed magnetic system.
Open magnetic system has no ferromagnet among magnetic poles. The radial magnetic system of the drum type magnetic separator, the column-like magnetic system of the dehumidifying tank, and the plane magnetic system of the belt type magnetic separator are all open magnetic systems. The selected gap of the closed magnetic system is the single layer or multi-layer. But the gap is very small, so the magnetic flux is generally straight. The resistance is small, and the magnetic flux is more concentrated with magnetic flux density and high magnetic field strength. The main mineral processing flowsheet is as follow: The original ore enters into the hopper. After vibration motor, the amount of material could be adjusted through the hand wheel. After the dry magnetic separator magnetic roller is through the speed motor drag, the rotation speed could be adjusted by instrument, which controls the magnetic separator production and concentrate grade. After the materials are handled by magnetic separator, the materials would be handled again with apron feeder and belt conveyor. This is very common in EPC companies. Different automated warehouse has different height, goods shelf, aisle width. The facility should be suitable for the type of warehouse. According to the height of warehouse, the automated warehouse could be classified as follows: The lower layers of automated warehouse:This kind of automated warehouse's height is under 5 meters, which is transformed from the old warehouse. This also an method to improve the technology level of automated warehouse. The middle-level of automated warehouse: This automated warehouse has height of 5-15m. This type has low requirement on the equipment of warehouse with low cost and wide application. The high-rise automated warehouse: This warehouse's height is over 15m. Because of high requirement on equipment, the installation is difficult and the application is rare. According to the structure of goods shelf, the classification is as follows: The format type automated warehouse: This kind of warehouse is widely used by clients. Each layer of goods shelf has the same size of space. Stacker reclaimer could operates in the passageway. Sometimes, the designer should also consider the belt conveyor design to coordinate the operation of the whole automated warehouse. The hollowthrough automated warehouse: This automated warehouse is called movable shelf warehouse. There is no interval and passageway set. The cabinet type automated warehouse:This automated warehouse consists of shell, controlling device, operation board, storage box, and driving device. It has features of closure, miniaturization, intelligent performance and security. The bar type automated warehouse: It is used to store bar-type and barrel-type goods. Also, the automated warehouse may involve in stacker reclaimer and pipe conveyor. So the quality of conveyor components is very important, which determines the whole operation of the conveying system. The belt conveyor is a kind of continuous conveyor in fixed line. The belt conveyor could transport the materials in horizontal, inclined or vertical direction. In general, the conveying line is fixed. The capacity of conveyor is large and the conveying distance is long. At the same time, other technological operation could be done in the course of conveying materials. As a result, the application of belt conveyor is wide in most EPC companies.
Besides, the confirmation on operating speed is very important for the belt conveyor design, which influences the conveying capacity and cost. Increasing the operating speed of belt conveyor could increase the conveying capacity. Under the same conveying conditions, selection of small belt width reduce the linear load and tension of conveyor belt. If the operating speed is increased, the dust would be raised. What's worse, the abrasion in feed channel and sweeper will be serious, which should be considered by designer. When the delivery value and belt width is large, the designer should choose high belt speed. If it is horizontal and long conveyor, the high speed should be chosen. When the belt conveyor transports materials with large dust capacity, the belt speed could be set as 0.8~1m/s .On conditions of labor burdening and weighing, the belt speed should be not over 1.25m/s. If the plow discharger is used, the belt speed should be not over 2.0m/s. If the throw-off carriage is adopted, the belt speed is not over 2.5m/s. When the finely-divided materials are conveyed, the allowed belt speed is 3.15m/s. If the complete goods is conveyed, the belt speed is generally less than 1.25m/s. The conveyor is commonly used in automated warehouse with other equipment such as apron feeder, stacker reclaimer and automatic robot. So please pay attention to the belt conveyor design for purpose of normal operation of whole project. There are many factors influencing the magnetic separation effect. The below are some factors from the magnetic separator itself. 1. The rotational speed of barrel of magnetic separator. 2. The deflection of the magnetic system 3. The working clearance(the separation between barrel and basal) 4. The separation of concentrate discharged The rotate speed of magnetic separator has influence on the magnetic separation effect. In generally, the magnetic separator with small diameter adopts high rotating speed. For example, the magnetic separator with diameter of 600mm adopts 36rpm. The rotating speed of magnetic separator has great influence on processing capacity. The high speed means good processing capacity, which could influence the quality of concentrate. The deflection of the magnetic system also influences the effect of magnetic separation. Too large or too small deflection is not good for the magnetic separation effect. If the deflection is small, the materials with weak magnetism will be selected, which would reduce the tailings grade. If the deflection is large, the quality of concentrate will be good, however, which reduce the recovery. In generally, the magnetic declination is adjusted between 15-20 degrees. The magnetic separator could select materials. And other equipment such as crushing machine, belt conveyor, stacker reclaimer could handle materials further. The off tracking of belt conveyor is the common problem in the production. Especially, belt conveyor installed in inclined drift is easy to have off tracking of belt. If this problem could not be solved timely, the coal production will be limited and the equipment performance will be worse, which would reduce the service life of belt and many result in accident.
If the off tracking of belt occur, we should confirm the reason and then solve it accordingly. We should deal with it according to actual conditions to guarantee the normal operation of the belt conveyor design. If the upper belt has deviation in one direction and the lower belt has deviation in the other direction, this could result from the large diagonal deviation. We could adjust the frame to higher place, making upper and lower idlers bear large load. There is no off tracking with load, while off tracking occurs without load. This situation is common where it is downhill and hanging segment. At this moment, the belt is controlled by several idlers. In the summon, the idler has large acting force to the belt. When adjusting this problem, the belt will be instable. When the belt conveyor operates without load, the belt and idler have no strict touch, which result in the situation that thrust force could not reach the belt. The solution is as follows: If possible, the tensity of belt could be reduce accordingly and the frame could be lifted. Also the vertical idler could be installed to adjust the off tracking of the belt. When fixing the idler, it will be better if the idler could rotate with the belt. In this way, the purpose of adjusting off tracking could be realized, which reduces the abrasion to the belt edge. Besides, the conveyor components play an important role. Most EPC companies would purchase the suitable belt and related conveyor components to coordinate the operation of stacker reclaimer and pipe conveyor. The stacker reclaimer is a high efficient equipment for the continuous loading and unloading of large bulk materials in modern industry. Now the stacker reclaimer has been widely used in ports, docks, metallurgy, cement, coal, steel plants, coking plants, coal storage plants, power plants, coal and other fields for handling bulk materials. There are three operating methods for the stacker reclaimer.
Semi-automatic operation: Before operating the stacker reclaimer, the workers would set related parameters according to the actual conditions. The related parameters include the rotating speed of stacking boom, rotation angle of stacking boom, pitching angle of stacking boom, detecting switch signal on the conditions of stacking materials. The related parameters for reclaiming materials involve in rotating speed, rotation angle, and nutation angle of scraper reclaimer, and control settings for the switch. After completing the settings of parameters, the semi-automatic operation for stacking and reclaiming materials could be started. The operating personnel could stop the operating of auto-programming. And then the worker could change related parameters to meet the requirements. The Semi-automatic operation is advised in production. Manual operation: Manual operation mode is based on the PLC program. Through the corresponding mechanism control button (or transfer switch), the operator manually control the stacker reclaimer to work. The operation process could be realized by the PLC program, and the corresponding mechanism has inter-agency relationship. Interlock operation: When the interlocking operation is carried out, the following operation procedure must be performed. Otherwise, it cannot be operated. Stacking operation conditions: A. Cantilever belt conveyor operates doing stacking operation; B. System belt conveyor operates in stacking direction. Reclaiming operation conditions: A. Belt conveyor operates in the reclaiming direction; B. Scraper reclaimer operates. In generally, the automated warehouse in the future may involve in pipe conveyor, stacker reclaimer, screw conveyor and other equipment. In recent years, the development of mining, cement, traffic construction, metallurgy, chemical industry, electric power and real estate promotes the blossom of the crushing machine industry. The crushing machine has different models such as jaw crusher, hammer crusher, impact crusher, cone crusher, high efficiency fine crusher, roll crushing mill, ring hammer crusher, toothed roll crusher, heavy hammer crusher. The different crushers have different performance. The jaw crusher is widely used in mines, railway, construction materials, water conservancy and etc. The jaw crusher has features of simple structure, good durability, easy maintenance, low cost and etc. This is a common crusher adopted by cement plant. The impact crusher could deal 100~500mm length of materials. This kind of crusher has features of wide application, low consumption, long service life and etc. A cone crusher is suitable for crushing a variety of mid-hard and above mid-hard ores and rocks. It has the advantage of reliable construction, high productivity, easy adjustment and lower operational costs. The roll crushing mill could be used for crushing ores or rocks in chemical and cement industry. The ring hammer crusher is used for fine crushing of materials in mines, cement plants, coal plants, railway and etc. The toothed roll crusher is used for crushing coals in mines, construction materials, metallurgy and other industries. The heavy hammer crusher has advantages of low operation cost, small matching motor power, large reduction ratio, large feed particle size and etc. |