It is very important for the concrete pole steam curing process in the production process of the concrete pole. It is the most important factor in the energy consumption and the key to the efficiency concrete pole mold turnover. The process of concrete electric pole steam curing process is the static stop stage, the heating stage, the temperature keeping Period and cooling stage, the temperature and cooling rate can not be too fast to prevent the occurrence of micro-cracks, affecting product strength, curing tank sealing performance affects the steam loss, and curing pool is the key equipment of pole production, it is good or bad design Big. This paper summarizes the structural design of the pole maintenance tank and the design points of the automatic control system through the practice of the maintenance of our company.
1. Structural design points
The structure of the curing chamber is generally three-layer structure, that is, the inner layer, the insulation layer, the outer layer of the structure; the inner layer can be used for concrete structure, the point is to have the appropriate expansion joints set, improper expansion joints or not set, The temperature is often caused by ups and downs caused by ups and downs, the use of a period of time there will be cracks, there run leaking steam phenomenon. Expansion joints generally according to the length of the body to set up 1 to 2 symmetrical structural expansion joints. Set up in the wall as close as possible to the upper part, to prevent the impact of gravity to withstand the strength of the middle of the arched as far as possible not to set the expansion joints; liner layer can also use steel welded structure, the use of this structure on the upper plate symmetrical micro-arched to prevent long time gravity The impact of the emergence of the collapse of deformation; liner laying also set the temperature point to consider the installation, the intake pipe concealed, the general intake pipe set at the bottom of the corner of the wall, so that does not affect the rail car into and out of space; Distribution of the stomata, symmetrical settings in order to maintain the temperature inside the pool can be uniform; temperature should be set in the middle of the height of the maintenance tank in the middle, close to the middle of the poles temperature area; to avoid set directly above the outlet. Steam curing daily boiler water consumption is relatively large, the collection and utilization of condensate is also a resource-saving measures, so the bottom of the inner layer in addition to set the track, the base surface set a certain slope and set the bottom of the sump, the regular start pump recovery To re-use the boiler. Do not forget to embed the embedded car into the embedded parts.
Insulation layer between the inner layer and the outer structure between the layers, but also can be determined according to the need to set whether the moisture barrier, moisture insulation material directly affect the insulation properties, so the inner layer and insulation layer if the sealing performance is not good, it is best to use linoleum Or asphalt to set the moisture barrier. Insulation layer generally use expanded perlite or insulation cotton; mine (rock) cotton source is rich, convenient procurement, suitable for low temperature, short life; glass wool acid, chemical stability, cheap, easy construction. Expanded perlite products, small density, low thermal conductivity, non-toxic, tasteless, not rot, cheap, suitable for wide.
Structural outer layer generally uses reinforced concrete structure, can also use steel structure engineering. The key part is the maintenance of the furnace door and the door hanging mechanism, one must have a good structural strength is another flatness, curing pool door opening mode and direction according to the specific space requirements.
Whether the use of mechanical groove seal will be complex structure, because the thermal deformation will affect the door switch, it can not be complicated, through practice, the most effective way is fixed. In order to save space is the key to open the steam, The kiln door side flat plane can be above the inlaid rubber rubber; rubber rubber can also be embedded in the door. In order to close the door after the door, one of the door's center of gravity position deviates from the curing pool door, the upper and lower door will not wear rubber, the second is the implementation of the door after the application of external force to close the kiln door; this institution can use the following figure, One can do sliding limit, the second can be close to the force, simple structure, easy to implement, easy maintenance.
Car into and out of the body design, poles carrying trolley in the steam curing pool and the common coin heating steaming, bad environment, it is not suitable for complex institutions, not allowed to have electrical parts. So the car can only be shown in the figure, the design into the pool automatically open the body to achieve a small car into the pool of a location, wire rope hook in the role of the column under the rotation of a position, release the rope, car in place, wire rope pull out the pool; When the car out of the pool as long as the rope routed car can be outside.
Metal structure to be anti-corrosion treatment; track is also an important part of the long-term load, resulting in uneven settlement will appear uneven, car out of the vibration, prone to collapse and bending, so the track straightness, level, track basis is also critical , Made of reinforced concrete structure.
2. Automatic control part of the design control system design
Automatic control part of the design control system design has two control methods, one for precision control, the use of electric control valve, a rough control, the use of electric switch valve, the program design is simple, low cost, low failure rate, to meet the poles Production requirements, the system hardware components are PLC touch screen, electric switch valve, temperature measurement device PT100, the system can automatically complete the whole process of steam curing, special circumstances can be transferred to manual control. The system can carry out temperature detection, control, recording and printing. Allows simultaneous cooking of multiple pool furnaces at different stages, through the touch screen and button operation can be based on different product requirements to set the process parameters, such as heating time, constant temperature and constant temperature and other parameters can see the temperature control process curve; Control design is the key to the PLC program, the program has three points of attention, one temperature control time, according to the steam temperature, diameter size; set three or four adjustment points; to our 1 hour heating time, for example, set three points , Every 15 minutes to check the temperature difference; more than the set range, it closed the steam valve for 5 minutes, so that the basic guarantee error within 5 minutes to reach the insulation value; the second point is the insulation phase of the temperature control, if set a Value, the program is simple, but the valve open and close frequently, reducing the valve life; so generally set to reach the temperature on the line, the insulation time, the temperature decreased 5 to 8 degrees Celsius and then open the valve temperature. The third cooling stage in the program set the insurance to prevent accidental warming.
The structural design of the electric pole maintenance tank is an effective means to save the resources and ensure the quality of the electric screw, and pay attention to the design points and rational planning. The realization of the temperature control of the pond furnace through the automatic control system undoubtedly played a positive role.