Select engineering needs of the concrete pump
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Select engineering needs of the concrete pump

1.1 Classification

From the mobility vehicle can be divided into concrete pumps (truck pump), frame pump (without the active arm), trailer concrete pump. Dynamic form from the electric and internal combustion engines can be divided into type. Form from the pump, there are currently widely used gate valve and inclined "S" pipe valve; the former has the advantage in the aggregate on the concrete requirements of a wide diameter (40 mm), small motor (75 kW) , at the lower price, a high degree of disadvantage is pumping only about 100 m; strict requirements which disadvantage is that aggregate (not more than 25mm), large motors (90 kilowatts), the advantage of pumping up to 150 m height above, but the price higher.

1.2 Selection

According to experience, the construction of large thermal power plant equipment is generally equipped with 2 sets of concrete mixing plant (station), 3 sets of concrete pump, a pump or two pumps of two truck towed a trailer pump, and multiple choice oblique gate valve to meet the aggregate requirements of such mobility, economy, practicality than reasonable.

1.3 Selection Considerations

(1) primary pump, the user must first visit the details about the actual usage.
 
(2) must use the regular production of the concrete pump manufacturers.

(3) try not to use any manufacturers of the first (first batch) concrete pump.

(4) should be at the direct sales contract manufacturers to buy as little as possible through the intermediate links, to facilitate maintenance services.

2, the new pump commissioning

Received at the factory before the 2.1 debug the contents of the pump

(1) composed of: technician, operator, driver and 1 who is skilled operator.

(2) Carefully read the instructions.

(3) an examination of the concrete pump model is consistent with the contract, the certificate number and plate number are the same.

(4) the appearance of satisfaction, if tainted, permeability Department.

(5) by manual operation, determine the maximum and minimum displacement movement of the piston when the number of transport. Such as Wuhan Tiger produced HBT60 pump minimum displacement pump 8 ± 1 times / minute, the maximum displacement of 28 ± 1 times / minute.

(6) Check the mixing system, cooling system, lubricating system is normal, the pump should also check the car boom boom system, outrigger systems, automotive parts are normal.

(7) load Operation 2 h, review of the system is tainted, permeability Department, during which the pressure gauge should be normal.

(8) Check all the random parts are complete, intact.

All qualified only after reception.

2.2 before using the site for the first time the contents of the debug

(1)then pump manufacturers repeat the debug content.

(2) The resettlement sites should be flat concrete pump solid, especially the legs supporting location. Construction concrete pump as close to the point, and consider the job after the end of the exit route.

(3) strengthening good layout and delivery pipeline (external receiver).

(4) empty load operation 10 ~ 20 min, so that all lubrication points are visibly grease.

(5) displacement pumping mortar 1 ~ 2 m3, when the mortar pump end quickly, they can pour concrete directly into the normal pumping.

Test pump, carefully observe the part of the work normally. Such as pumps, oil temperature, the main gauge changes, frame pump and engine should also pay attention to the work arm action, if any irregularities should be immediately shut down, identify the reasons for troubleshooting after the retest. Do not wash after pumping the pump, carefully check the ministries are seamless, oil leakage phenomenon, qualified and then wash the pump or directly put into use.

3, pumping techniques

Ease of concrete pumping (ie pumping effect) generally depends on the quality of concrete itself, casting distance, duct size, piping as well as to prevent the plugging of a sudden blocking tube and remove and so on.

(The quality of concrete pumping concrete itself effect a greater impact, but here no description)

3.1 Pipeline choice

According to Table 1, the maximum size of coarse aggregate concrete table to select the appropriate pipeline.

3.2 The layout of foreign takeover

Should minimize the use of pipe, the pipe should be severely worn cloth in the locations far away from the concrete pump, the pressure is too high to avoid burst pipes.

Converted to various forms of horizontal piping length (approximate).

3.3 The exclusion of concrete pump plugging

(1) Anti-blocking pipe when the pump exclude, you can press the "anti-pump" switch, the general anti-pump running 4 to 5 trips can be ruled out.

(2) When the anti-pump operations can not rule out blocked tubes, you should open the plug at the pipeline as soon as possible, and clear the obstruction. Note In addition to cut off the power before demolition control, they also need the complete elimination of residual pressure inside the tube.

3.4 Construction of the season

Hot summer weather construction, to use the wet drop cloths, straw bags and other covered pipes, concrete pipes to avoid "spin", transportation difficulties. Construction of the winter cold season, it is appropriate thermal insulation material wrapped pipes, to prevent the cold concrete pipe.

3.5 Notes pumping operation is completed

(1) thorough cleaning of concrete pumps and foreign takeover.

(2) Check the packed random tools.

(3) 20 min air running full of grease to the lubrication points.

(4) retired from the job site safety.

4, routine maintenance

As more types of concrete pumps, here only some general maintenance.

4.1 The inspection items before departure

(1) jib, slide valve and the leg should be fully retracted and locked.

(2) work lights, signaling devices work properly.

(3) have sufficient fuel, grease and wash water.

(4) hydraulic oil enough, the parts do not leak.

(5) a variety of piping, tools, equipment and accessories should be complete.

4.2 The main components of inspection cycles

(1) Daily check the appearance of damage deformation, loosening of the exposed parts, operation and performance changes, leakage of oil, hose damage, lack of grease lubrication points, driving insecurity.

(2) Monthly (or pump concrete 2 000 m3) Check the slide valve damage, wear and tear ducts, hydraulic oil less lubrication points, lubrication, automotive part of routine maintenance.

(3) months (or pump concrete 12 000 m3) Check the slide valve under the shell, conveying cylinder damage, electrical components, hydraulic oil deterioration, arm injury, automobile part of routine maintenance.

(4) year (or pump concrete 24 000 m3) Check the mixing device, mixing motor oil, oil rotary motor, water pump, the pump, replace the hydraulic oil.

(5) every two years (or pump concrete 48 000 m3) inspect all items note that the seals were opened to replace them all the time, car parts should be points in the specified or a professional repair maintenance accordingly.

4.3 hydraulic oil and lubricating oil, grease selection

Hydraulic Oil Type: Winter 32, anti-wear hydraulic oil, non-winter 46 hydraulic oils.

Slide valve Lubrication: Winter Model 000 with the number of non-extreme pressure lithium based grease, non-winter use of Type 00 non-extreme pressure lithium based grease.

Vehicles and the rest of lubrication: grease 2 or calcium-based reference manual.

5, the vulnerability of repair

5.1 Scope Repair

Slide valve in the chuck of concrete pumps, components and concrete contact with a lot of wear and tear are very powerful, and we can fix only the individual components, the remaining parts, such as rubber, concrete transport cylinder, smooth stem and other pieces of fine processing, General to be replaced. Repair of worn parts is divided into two categories: one is welding repair parts, such as the slide valve plate, slide valve end cover (also known under the spool valve housing), slide valve, the next seat, mixing blades; other One is welding repair, mainly for concrete pipes.

5.2 Detection of wear

Slide valve plate generally lower wear serious, when the new size and worn parts is greater than 5 mm size difference, that is to be repaired; slide valve on the middle seat wear under severe wear when the new pieces of size and size difference of greater than 4 mm, that is to be repaired; mixing angle of serious wear and tear on both sides of the leaves, when the new size and worn parts is greater than 8 mm size difference, that is to be repaired; slide valve cover bottom and sides of the bottom of serious wear and tear, when the new parts size difference of size and wear and tear is greater than 5 mm, that is to be repaired.

5.3 Repair process

(1) to determine the end of the slide valve cover material chemical composition of the test results, C: 3.13%, Si: 2.06%, Mn: 0.83%, P: 0.102%, S: 0.126%; hardness HB203 ~ 228; material can be determined cast iron for the MT-4.

(2) select the bottom of welding electrode should be used in thermal cracking good performance austenitic nickel-based electrode Olympic 102, Olympic 302. To further enhance the wear resistance welding parts, to ensure the base metal does not crack under the premise, but also use carbide electrode stack 667, stack 507 implemented in the surfacing welding layer on the surface.

(3) welding method used before the Olympic 102, Olympic 302 electrode in 105 ℃ ~ 200 ℃ drying 1 h, reactor 667, reactor rod 507 at 300 ℃ ~ 450 ℃ drying 2 h, in order to reduce the hydrogen welding silkworm content, to prevent holes. Two electrodes are AC welding machine, the former current of 100 ~ 110 A, which the current 130 ~ 140 A.

Grease the surface of the welding parts, concrete and other impurities clean, rubbed off with a defective wheel shaft fatigue level, so that the surface of exposed metallic luster. With asbestos or cotton cloth wrapped around the cylinder and components, to prevent burns when welding. On the bottom cover preheated to 150 ℃ ~ 250 ℃, to prevent cracks. Welding electrode moving direction when feeding straight line method. Welding sequence welding method by subsection retire, retire from the inside out, but the direction of electrode movement from outside to inside. The length of each segment of the surfacing not more than 50 mm, try to avoid welding heat. After a section of each weld, reinforced by careful percussion sharpened in order to eliminate residual stress and prevent cracking occurred. After finished welding, and immediately wrapped with asbestos, so slow cooling. After cooling, the use of welding part of the grinding wheel surface grinding machine. After grinding, with the coloring inspection confirmed that no more than 30 mm crack. Note that the heap can only be 667 or 507, welding the surface layer of the heap.

In addition to pipes, other wear parts can be cover by the end of the slide valve repair methods, and steps can be a simple.

(4) four sub-pipeline repair briefing as follows:

① pipeline fell flat the first to do a simple jig can also be used instead of vice, and then prepare a pipeline diameter and the diameter of close to (slightly less than) the steel pipe, steel handle into a bullet-shaped at one end, so just to fall flat at heating, with a round steel can be corrected.

② local repair pipe generally worn out, because under normal circumstances, a part worn straight, the remaining parts are close to wear limits, no repair value, while the elbow bend the Department generally will be worn. Repair method is to cut the waste pipe of a moderate size of the film material, and the site of injury with a grinding wheel machine and sheet materials, select the appropriate pipe welding electrodes can be. During the repair of curvature should be noted.

③ tube hoop off the waste pipe can be cut with pipe collar part of the hoop tube length should be carried by pipeline at 45 ~ 55 mm, with a welded part of the grinding wheel machine, you can select the appropriate welding rod.

④ straight hole with a wear limit (bending) tube if the drain hole plasma, the general not to repair use, such as to repair to use, available over the end of the outer low pressure. In fact, the general repair of ducts are best to use out over the tail, the ban on the arm.

6 How to extend the life of the slide valve

Inclined concrete pump, often encountered in the course of premature failure of the slide valve problems, mainly as follows: injury site mostly stem slide valve, the valve stem axial depth varies irregular grooves stem movement resistance, upper and lower can not reach the desired position, the valve stem by the card can not be serious movement. At this point must be downtime or even to replace the valve stem or spool valve assembly, neither has a direct impact on the economy of concrete pumping work. After the disintegration of the slide valve by the general performance of: nylon seal serious damage, breakage there are the sand, small concrete blocks, and even pebbles; grease clogging the supply pipe to the top there.

The analysis, may cause damage to the slide valve factors: ① lubrication system failure; ② improper operation (before work or after work load operation is not enough space); ③ poor quality grease; ④ poor quality of concrete; ⑤ the quality of the slide valve itself poor; ⑥ slide valve trauma. One of the most likely factors causing the slide valve damage, mainly lubrication system failure and improper operation.

Lubrication system consists of slide valve box grease, filters, grease pumps, dampers, valves and grease grease distribution lines and other components. The key component is the grease distribution valve.

Slide valve lubrication system failure is required lubrication points can not be lubricated or lubrication is not good, but not specifically identified what point lubrication, grease distribution must also be observed on the valve rod and valve distribution valve display bar indicates the work necessary, the interface needs to observe the release of the lubrication points. Lubrication distribution valve formed by the distribution valve and safety valve, shown in Figure 2. Its role is to pump the grease from the grease assigned to the specified location. When a fat pipe for the top of a mortar was blocked, the valve rod will extend shows that for the lipid abnormalities. Distribution valve distribution valve is also equipped with display bar, under normal circumstances for the fat cycle 1, indicating lever action 1, if the display bar means that the distribution of the fixed valve dysfunction. Lubrication lines and between the various lubrication points without replacement properties.

Full use of the actual work Ruoxiang good pump, but also accumulate more practical experience, and continuously improve operator proficiency, minimize pumping concrete pump Troubleshooting time to make concrete pump should play in building construction role.

 

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createtime 2011-01-04 author webmaster view count