Technical management of disassembly and assembly operations of large-scale mixing equipment

The installation and dismantling of large-scale mixing equipment is an important part of equipment management and project management. Attention should be paid to multiple aspects such as equipment protection, civilized construction, environmental protection and occupational health and safety. Effective management of the disassembly and assembly operations of large-scale mixing equipment is the guarantee of its good performance, and it can also extend the service life of the equipment and better serve engineering construction.

I. Organizational Machinery and Responsibilities

Before disassembling and assembling large equipment, an organizational structure involving personnel with installation experience and technical skills must be established to be responsible for the scheduling, supervision, coordination and management of the equipment disassembly, transportation, installation and other operation processes. Conduct a thorough analysis of elements such as equipment features, operation costs, environmental factors, and hazard sources, and implement standardized management and operation throughout the entire process of parking site selection, planning, and disassembly and assembly operations. Based on the characteristics of the equipment, corresponding implementation plans should be formulated. The implementation plans should cover the specific contents and responsibility requirements of the operation process technology, safety, sequence, crane selection, and sanitation and cleaning, and each specific task should be assigned to an individual.

During the process of equipment disassembly, transportation and installation, corresponding operation teams are established at each stage according to the process arrangement. Collect all the documents, materials, pictures and other materials involved in the entire process of disassembly, transportation and installation, and organize them into volumes.

Ii. Work Process Management

1. Site treatment

When choosing the site for the new equipment installation, factors such as equipment safety, loading and unloading, and material transportation should be comprehensively considered. At the same time, efforts should be made to avoid any impact on the project's living area and nearby residents. The site layout should not only meet the requirements of production and use, but also the requirements of equipment safety, environmental protection and occupational health and safety. The ground around the control room, the main building, the drying drum, the track, the powder tank, the finished product silo and other areas must be hardened to meet the usage requirements and environmental protection requirements for cleaning up waste materials, accumulated dust, etc. The specific hardening standards can be formulated by the project department based on factors such as the length of the construction period, construction scale, foundation conditions, and construction season. Where conditions permit, the main traffic roads on the site can also be hardened. At the same time, it is essential to ensure smooth drainage on the site to prevent water accumulation.

2. Dust and powder treatment

Dust and powder generated during the production process should be properly handled. Cement mixing equipment should be designed with cement filter tanks, and appropriate dust treatment measures should be taken for asphalt mixing equipment.

3. Foundation treatment

The basic treatment must meet the requirements of the equipment foundation drawing. The dimensional relationship in the foundation drawing and the requirements for strength, load, elevation, etc. should be carefully analyzed. The dimensional relationship is verified by the layout of the measuring instrument. Samples of cement concrete should be taken as specimens for strength testing. The load capacity should be handled with caution based on technical requirements such as equipment drawings and the specific conditions of the ground. For instance, for soft foundations and other situations, reinforced concrete integral foundations and pile driving treatments should be carried out. The overall horizontal level of the foundation should meet the requirements of the drawings. If conditions permit, it is advisable to be 20-40cm higher than the ground. If the foundation drawings need to be modified, the modification plan must be filed. For foundations subject to heavy loads (such as main buildings, powder tanks, drying cylinders, winches, etc.), it is advisable to directly and accurately pre-embed anchor bolts. For some foundations with varying supports, irregular sizes and large forces, steel plates with a thickness of more than 1cm can be welded onto the embedded reinforcing bars and then welded to the support feet. For some foundations with low force requirements, holes for anchor bolts can be reserved for secondary pouring. The lightning protection grounding grid should be carried out simultaneously with the foundation. After the foundation is laid, the center line should be marked out and the center piles should be well protected for installation and correction.

5. Transportation

When transporting, the qualifications of the transportation unit should be reviewed. If over-width, over-height or over-weight transportation is required, the transportation unit must have the corresponding license. When loading each component onto the vehicle, a dedicated person must be assigned to track the loading situation to strictly prevent the components from being crushed. Detailed records should be made, and a list of items to be dispatched along with the vehicle should be filled out. Photos can be taken for record-keeping during the equipment's transfer out, in and transportation. After the components arrive, a dedicated person familiar with equipment installation should be organized to conduct acceptance according to the implementation plan. Large components should be placed as close to the installation position as possible, and loose components should be placed in an orderly and centralized manner. And make good marks and fences, and keep them by a designated person to prevent loss. It is recommended to purchase insurance for important equipment components.

6. Installation

(1) Preparations before installation

Before installation, the appearance quality of the equipment should be rechecked. Check if the bolts are loose, if there are cracks at the welds, and if there is any oil leakage, water leakage, dust (lumps), etc. Carefully clean all assemblies of the entire machine. If necessary, repaint, prevent rust and refurbish them. Prepare all the necessary specifications of bolts, welding rods, iron plates, etc., as well as tools and safety protection equipment. For tools that are frequently used, several sets should be prepared. If conditions permit, pneumatic wrenches can be used, and timely oxygen cutting and electric welding equipment should be equipped. Plan the entry time of the crane well.

(2) Installation of mechanical parts

Identify the assembly components with installation sequence requirements and install them in sequence. For assemblies without installation sequence requirements, flexible arrangements can be made based on on-site conditions. If necessary, multiple working surfaces can be carried out simultaneously. During installation, attention should be paid to the alignment and dimensional relationship between them. The sealing parts should be strictly treated to prevent leakage. The oil pipes and the connecting pipes can be connected in sequence from the starting point to the end point. If necessary, the oil tank or dust collector can be lifted and moved first to reduce the work of cutting and welding. The diesel pipeline is recommended to be connected by flange. If galvanized pipe tapping connection is used, after installation, it should be sealed with water-based adhesive tape or fiber thread and treated with paint. The oil can be connected after the paint dries. When installing the dust collector, it is necessary to first check whether the filter bags are intact and clean the remaining dust powder. All seams should be sealed with rubber sheets or with thick glass glue that has solidified. After the mechanical parts are installed, lightning protection measures should be taken in a timely manner. For recycled powder that is no longer in use, discharge treatment measures should be implemented. Treatment measures such as filter tanks should be set up for the waste slurry from cement mixing plants.

(3) Cable installation

Before wiring, carefully check whether the cables are intact, free from damage, open circuits and short circuits, and whether the insulation and resistance of the power cables are in good condition. When wiring, operate according to the equipment circuit schematic diagram. Do not only check the disassembly records, and it is strictly forbidden to tamper with the circuit privately. Improvements due to component changes or circuit defects should be filed and recorded. The circuit layout should be as far away as possible from the oil circuit and high-temperature and humid areas to avoid the intersection of the circuit and the oil circuit. If there is an intersection, the oil circuit should be strictly sealed. Safety warning signs and strict oil-proof warning signs should be set up at the cable trench (trough) location. Grounding of each part should be carried out simultaneously with wiring and must be reliable. Lighting circuits should be arranged and installed synchronously with the overall machine circuit. Metal conduits should not be added to single-phase power cables to prevent overheating and damage. Control and signal cables should be designed and laid separately from power cables. After the power cables are laid, they can be separated by sand and soil layers or by conduits (troughs). The lines should be properly concealed and protected, and be aesthetically pleasing and clear. Soft rubber should be laid at the corners to prevent mechanical vibration and wear.

Circuit wiring should be carried out by at least two people together, each responsible for the wiring operation and inspection and verification to prevent incorrect connections. Wire lugs must be used at the line joints, and tight pulling and rehanging should be avoided to prevent detachment.