Talking about the operation and management of municipal drainage pumping station.

What are the problems in the operation and management of municipal drainage pumping stations? The following is a detailed introduction of Zhong Da Consulting for your reference.

1. Main construction technology in the construction of municipal drainage pumping station

1. 1 construction joint treatment

When cast-in-situ concrete is used in the enclosure structure of pumping station project, continuous casting is generally used in the vertical parts such as pool wall and partition wall to avoid construction joints. The time interval between two construction layers shall not exceed the initial setting time. Correctly mastering the secondary vibrating technology can not only improve the cohesion of construction joints, but also improve the compactness of concrete. That is, the concrete poured first is vibrated again before and after the final setting (usually 2-4 hours), and then the next concrete is poured. If construction joints must be left, they should be left in the parts of the structure where the shear force is small and convenient for construction. Generally, horizontal construction joints can be made by the following methods: (1) In order to combine new and old concrete firmly, the contact surface should be cleaned and chiseled, and a layer of cement mortar with the same proportion as that in concrete should be laid on the surface of old concrete, and its thickness should be less than 2 cm. Then, concrete can be poured before the mortar sets. (2) For projects with high water pressure or high waterproof requirements, the treatment of construction joints also needs to consider burying water stops and carefully tamping them.

1.2 waterproof requirements for concrete

In the design and construction, it is emphasized that the self-waterproofing of the structure should be done well, and the requirements of impermeability grade should be made clear. The key to self-waterproofing of concrete structure is to ensure the compactness of concrete and control the cracking of concrete. Paper reference network. We can start from the following aspects. (1) water-cement ratio: reduce the water-cement ratio as much as possible without affecting concrete mixing and tamping and avoiding honeycomb pits. (2) Mix proportion: Pay attention to improving aggregate particle size, and use platform cement and sand. (3) Construction conditions Pay strict attention to the concrete mixing, transportation, pouring, tamping and other construction processes, and take effective maintenance measures. (4) Admixtures: Admixtures (compaction agent, waterproofing agent, water reducing agent and air entraining agent) are properly mixed into ordinary concrete mixture. Waterproof concrete with good impermeability can be made by adding 3% compaction agent to block capillary channels in concrete and adding air entraining agent to form tiny closed pores. Generally speaking, the maximum water-cement ratio of cement concrete should be controlled below 0.6. When the cement grade is greater than 425 and fine active powder is added, the cement dosage should not be less than 280kg, and the selected cement is pozzolan or ordinary portland cement. The maximum particle size of stone should not be greater than 40mm, and medium-coarse sand should be used as the sand. In addition, spraying protective layer on the surface of concrete structure can also improve the waterproof performance of cement structure.

1.3 Waterproofing of through-wall pipes

There are many kinds of through-wall pipes in pumping station engineering, which are the weak parts of waterproof. The common waterproof methods for through-wall pipelines should be carefully treated as follows: (1) Wrap a circle of water-stop rubber in the middle of the through-wall pipeline, and embed two-component polysulfide rubber in the root of the pipeline. Paper reference network. (2) Spray polyurethane (PU) foaming filler in the gap between the wall-penetrating pipe and the wall. The foaming filler is liquid before use, and it foams after being sprayed into the gap, and its expansion reaches 45 times. Practice has proved that this method has good waterproof effect and simple operation.

1.4 deformation joint setting

In order to avoid cracks in concrete structures, deformation joints should be set for larger pool structures, which should meet the requirements of sealing, waterproofing, deformation adaptation and convenient construction. The common types are caulking type, adhesive type (adhesive rubber sheet), embedded rubber water stop and attached rubber water stop. However, these types of deformation joints are not ideal, because improper handling of deformation joints will lead to a large number of water leakage in the pool. Three types of deformation joints, namely embedding, caulking and pasting, can be combined to form multiple lines of defense and improve waterproof reliability.

2. Problems and solutions in the operation of municipal drainage pumping station equipment

2. 1 pump

The water pump is the core of the pumping station, and the lifting and discharge of rain (sewage) water is realized by the water pump. In pumping stations with multiple pumps, the current of the side pump is higher than that of the middle pump, and the current of some pumping stations is higher than 20%. Some pumping stations must start the side pump first, otherwise the side pump will not start, which indicates that the flow pattern of water diffusion in pumping stations is not good, and the water distribution is uneven and unstable. Some pump houses are equipped with multiple pumps, but the water outlet tank uses lateral water outlet, which leads to large water outlet resistance and running current, and even the side pumps far away from the water outlet frequently trip. It shows that the layout of the outlet pipe of the pumping station is unreasonable and the head loss is too large, which seriously affects the operation of the pump. Main faults in water pump operation. (1) sundry jam. During the operation of the water pump, due to the garbage and sundries in the water inlet pipeline, the pump blades are easily stuck by sundries or damaged by hard objects such as wood blocks and steel bars. In operation, it is often found that the pump suddenly trips, the current is too large, the motor is blocked, the vibration is too large, and abnormal noise occurs. After the pump is lifted, it is found that there are a lot of sundries in the pump impeller, or it is stuck by wood blocks or steel bars. After cleaning the impurities in the inlet pipe and water tank, the frequent blockage of the water pump is basically eliminated. ② The water pump cable is worn. Most of the pumps used in sewage pumping stations and large rainwater pumping stations are submersible sewage pumps and submersible axial-flow pumps. Most cables of submersible pump are in the water. If it is not fixed properly, the cable will shake with the operation of the pump, and the cable will wear after a long time, which will lead to the pump entering water or the cable short circuit tripping. In the process of operation, due to negligence or lack of experience, problems were not found in time, which led to such failures of pumps. Therefore, in the operation of the pump, it is necessary to regularly check the fixing of the pump cable to prevent the cable from being worn and affecting the safe operation of the pump. ③ cavitation. During the regular maintenance of water pumps, it is found that some pump blades are seriously cavitation, almost all vertical axial flow pumps will have cavitation, and some blades are damaged to 1/3- 1/2. After the blades are worn, the pump flow decreases and the vibration intensifies, which seriously affects the normal operation of the pump. After the pump cavitation occurs, the design department should be consulted to review the operating conditions of the pump to test whether the operating conditions and cavitation allowance of the pump meet the requirements.

2.2 cleaning machine

The main function of the cleaner is to intercept a large number of solid sundries in rain (sewage) water and prevent sundries from entering the water pump and blocking the water pump. Judging from the effect of cleaning machines, some well-known brands have stable operation and low failure rate, but their prices are higher. Household cleaning machines are cheap, but the failure rate is relatively high. In the process of operation, it is often blocked by wood blocks or fiber fragments. If the protection cannot work in time at this time, it will often damage the cleaning machine. Such as rake tooth deformation, grating deformation, frame displacement, etc. Therefore, sensitive, reliable and complete protection plays an important role in protecting the normal operation of the cleaning machine. Because there are many sundries in the water, the rake teeth are very easy to get stuck in the rotary cleaner, especially when there are many sundries. Therefore, only by increasing the frequency of cleaning and fishing and observing frequently can the sticking times be reduced. Paper reference network.

2.3 categories of electrical equipment

There are more and more power transformation and distribution equipment in pumping stations, and the trend is increasing year by year, and the safety level exceeds the standard. At present, the transformation and distribution equipment used is not updated quickly, and some water pump starting cabinets are started by one-to-one autotransformer. In operation, electrical equipment failures will be encountered more or less: (1) electrical connectors are overheated. After running for a period of time, the electrical connector will be corroded to varying degrees, which will make the contact surface smaller and the water pump will generate local heat when running. If it is not found in time, it will burn equipment or lines. Therefore, in the process of equipment operation, we should check the contact and tightness of each electrical connector, and form the habit of regular inspection. (2) The protection setting value is unreasonable. After long-term operation and aging, the current and voltage will fluctuate to varying degrees. Many electrical protection devices (such as thermal relays and short-circuit protectors) have the protection settings of the corresponding protected equipment. When the electrical equipment fluctuates due to aging current, it will lead to over-sensitive protection and frequent tripping of the equipment, but it is found that the equipment is normal after inspection. When the set value increases, it will cause equipment failure, and the power protection equipment cannot be cut off in time. Therefore, the running state of the equipment should be carefully checked during the operation to ensure the safe and reliable operation of the equipment.

3. Concluding remarks

In the construction and operation of municipal drainage pumping stations, many unexpected problems are often encountered, which may be far more than the above points. The key is to see whether our engineers and technicians can accumulate experience, prevent the failure from happening again as much as possible, and take effective measures to solve it quickly after the failure, so as to ensure the normal operation of the drainage pumping station and maximize the benefits.

For more information about project/service/procurement bidding, and to improve the winning rate, please click on the bottom of official website Customer Service for free consultation:/#/? source=bdzd