water 的各种加工工艺许多的用户都十分的好奇，由于用户一般是看不到这个具体的出产制造进程的，尤其是大口径的水泥管 ，到底是用什么方法出产的呢？ Many users of mud pipe processing technology are very curious, because users generally do not see this specific production process, especially the large diameter cement pipe , in what way is it produced? The following editor of Guangzhou Wanxin Cement Pipe Company will introduce it to you:
Centrifugal pipe making process: plastic concrete is used, and the wall structure of the pipe is layered after molding, which affects the ability of the concrete to resist the load. The general designation of the concrete is C30, which can also achieve C40, but the concrete weight of the pipe mouth is lower than the pipe It is not suitable for pipe jacking; when the pipe mold is lying on the centrifuge at high speed during molding, the steel mesh will move along with it, which will show two conditions that affect the service life of the tube: 1. The steel mesh will show in real time if there are no welding points. The phenomenon of running and leaking tends to make the tube part appear to have no tendons. 2. After the forming, the reinforcement mesh is difficult to center. The reinforcement mesh is painful, that is, the protective layer of the reinforcement mesh is uneven. This process requires a lot of molds. To ensure the output, the dimensions of each mold are wrong. The long-term disassembly and application of the split mold will also show large deformation, which results in the roundness of the pipe, the straightness of the nozzle, the diameter of the pipe, and the length of the pipe. Large errors affect the quality of the project's installations. Leakage will cause the road surface to sink and cause pollution to the soil and groundwater on both sides of the pipeline;
Suspension roll pipe making process: dry and hard concrete is used, the wall concrete structure is uniform, and the ability to resist loads is outstanding; the concrete designation is generally C30, C40; the noise during molding is reduced compared to the centrifugal process, and the operating site environment is cleaner than the centrifugal process Some; the disadvantage is that the wall thickness must be increased when making small-diameter pipes to meet the impermeability requirements; some other disadvantages of the centrifugal process are the same as the suspension roll process.
The production process is as follows:
I. Reinforcement skeleton manufacturing :,
1. On the reinforcing steel frame forming frame, adjust the outer diameter of the forming frame according to the practical requirements of the inner diameter of the reinforcing steel frame ring reinforcement according to the drawing reinforcement requirements, and make equidistant symbols on the supporting frame according to the ring reinforcement pitch.
2. Rotate the reversing forming frame, and wind the circumferential reinforcement on the forming frame in accordance with the pitch symbol. Pay attention to the accuracy of the number of loops and the pitch. The overlap length of the circumferential reinforcement at the two ends of the steel frame must not be less than 300mm, and it should be welded.
3. Place the longitudinal bars that have been straightened and cut to a fixed length in accordance with the planned orientation. The ends and the ring bars are welded. Note that the azimuths of the two side ring bars are not 10mm away from the ends of the longitudinal bars.
4. When using manual arc welding to strengthen the reinforcing steel skeleton, the longitudinal and ring bars should be pressed against each other in advance, and a thinner electrode should be used to adjust the welding current of the arc welding machine to be small. On the basis of ensuring the welding quality, try to avoid severe erosion of the steel bar. , If necessary, sample the welded part to check that the tensile strength is not lower than the base metal.
5. Reinforcement points are gathered at the two ends of the reinforcing steel skeleton and at the positions where there are standing ribs between layers.
6. Double-layer steel bars are supported by prefabricated stand bars. The orientation of the stand bars is on the longitudinal bars at the two ends of the skeleton, and the number of stand bars is 3 to 5 per distance of one longitudinal bar.
When the artificial reinforcement is used to form the reinforced steel skeleton completely, it is necessary to use cold-rolled ribbed steel bars for longitudinal reinforcement, and artificial arc welding for reinforcement at both ends of a joint is necessary to avoid the circumferential steel bars from being displaced by the impact of falling concrete.
Second, the mold assembly:
Operation steps and matters needing attention:
1. Carefully apply oil to the socket ring and set slotted bolts so that the gap between the inside of the steamed socket ring and the pipe socket will not damage the pipe socket when the socket ring is removed.
2. The inner wall of the outer mold is evenly coated with cleaning engine oil, and the mold is clamped outside the reinforcing steel frame, engaging the joint bolts, and paying attention to avoid pinching the reinforcing bar in the joint.
3. Tighten the joint bolts in order. The tightening force should be moderate, not only to avoid leakage of the joint, but also to prevent the mold from being out of round. In order to allow the later socket ring to be smoothly inserted into the top of the outer mold, Avoid temporarily tightening the two bolts. Leave the socket ring in place before making up the tightening.
3. Concrete preparation:
1. Condensate grade: C30 concrete is selected;
2. Reference cooperation ratio of concrete: cement: sand: stone: water = 1: 1.54: 2.88: 0.43
Concrete capacity is 2400kg / m3;
The amount of cement is 410kg / m3; sand: 632kg / m3; stone: 1181kg / m3; water: 175kg / m3; sand rate: 35%; needs to be selected after testing and verification in the laboratory.
The slump of concrete is: 10 ~ 30mm.
Note: The water-cement ratio should be controlled accurately. Excessive slump will cause the concrete to oscillate and segregate. The mortar rises and the pipe cracks. If the slump is too small, the oscillation will be more difficult, the structure will be empty, and the pipe will not be dense.
3. Data quality requirements:
Cement: P · O 42.5 or 42.5R grade, the alkali content meets the requirements of low-alkali cement, and the delivery time is shorter than 3 months.
Sand: River sand, fineness modulus Mx = 2.3 ～ 3.0, mud content and mud block content must meet the requirements of standard specifications.
Stone: crushed stone, continuous grain size, standard: 5-20mm, each target must meet the standard specifications.
4. Concrete technical requirements:
Adjust the actual measurement value of the batching machine according to the planned cooperation ratio. The measurement error of cement is not more than 2%, and the measurement error of sand and stone is not more than 3%;
The feeding order is reasonable, the mixing time is sufficient, the water-cement ratio is accurate, and the workability is ensured. When mixing in the first plate, it is appropriate to take part of the water properly to make up for the water absorbed by the mixer and the pipe mold, which makes the appearance of the pipe dry and gives a honeycomb and hemp surface.
The mixing time depends on the type of mixer. The type of mixer is recommended to use single or double drum mixers. The mixing time is not less than 2 minutes. In winter, it is necessary to have a thermal insulation method. Sand and stone do not promise frozen blocks.
Fourth, the pipe forming:
1. On-site process organization:
The production site is divided into the steel frame forming, concrete preparation and feeding, mold assembly and pipe forming, steam maintenance and pipe demoulding.
2. Management operation and matters needing attention:
1) The requirements of the suspension roll cement pipe making machine should have sufficient rigidity, and the ratio of the outer diameter of the roller shaft to the inner diameter of the pipe is 1: 3 to 1: 5.
(2) Suspended roll forming is divided into two stages: feeding and net rolling. The feeding amount should be controlled after the compaction of the concrete is 3 to 5 mm thicker than the retaining ring.
V. Maintenance, demoulding and storage:
1. Steam maintenance:
(1) The steam maintenance of the tube can be completed at one time (that is, the maintenance center does not demold).
(2) Put the formed pipe into the steaming pond and cover it for maintenance (the steaming temperature is controlled at 80 ~ 85 ℃); in order to avoid the concrete cracking of the pipe, it is necessary to ensure that the pipe is at a standstill during the initial stage of pipe forming, In the early stage of raising, slowly release steam and gradually increase the temperature, and strictly maintain the pipe in accordance with the static stop ------ heating ------ constant temperature ------ cooling (natural cooling). Maintenance guidelines are: four phases: static stop, heating, constant temperature, and cooling:
Static stop: After the tube is formed, it is left at room temperature for 1-2 hours
Temperature rise: The temperature rise is no more than 25 ° C per hour, and the time is continuous for 2-4 hours.
Constant temperature: The constant temperature time varies with the power of the steam pit, the type of cement, the condition of the admixture, and the thickness of the pipe wall. The strength of the demoulding concrete should be ensured. Generally, it should not be less than 3 hours. Constant temperature maximum temperature: Portland cement 80 ° C, Portland cement 85 ° C, Slag Portland cement 95 ° C.
Note: The purpose of static stop is to make the cement in the concrete reach the initial setting strength to resist the influence of temperature and the transpiration of free moisture: if the heating rate is too fast, it will cause uneven temperature inside the concrete and cause temperature difference cracking.
(3) The steam curing benefit is controlled by the compressive strength of concrete test blocks in the same period. When the concrete strength reaches 75% of the planned strength, it is agreed to take off the outer mold and lift the pipe.
2. Lifting and storage of pipes:
(1) Pipes should be hoisted by mechanical equipment and artificial assistance. After the pipe is hoisted, it must be stable in the air.
(2) After the pipe is hoisted to a wide place, slowly lower it to store it in a horizontal condition.
(3) The appearance quality of the pipe after demoulding shall be checked, and the pipe with appearance defects shall be repaired in time.
Note: The data of the repaired pipe has a setting strength not lower than that of concrete. Emulsified epoxy resin slurry or construction adhesive is generally used. After the damaged repaired base is treated, the cement and white stone powder are reconciled to bring the color closer to the nature of the concrete. After the repair agent has coagulated, use sandpaper or the like to smooth the repair surface.
(4) The pipe after demoulding should often be watered for continuous maintenance, and covered with a film, and maintained for more than a week to avoid concrete cracking.
Note: Water production is not allowed for winter maintenance.
1 Factory inspection items: concrete compressive strength, appearance quality, scale errors, internal water pressure, external pressure inspection, etc .;
2 Product quality inspection before passing the factory.