How do mud and sand transporters unload mud and sand? What kind of mud or sand pumps are used? Mud and sand transporters usually transport mud and sand mixtures from river dredging, construction sites, and mineral extraction through flat-bottomed boats, and then use mud pumps, sand pumps, or excavators to unload mud and blow it into the landfill area. How does a silt transport ship unload silt, how to choose the appropriate silt unloading pump and sand unloading pump for operation, can long-distance transportation of silt be achieved, and what is the approximate cost of unloading silt? The technical department of Ocean Pump Industry has specially compiled this article for your reference through years of construction plan design accumulation
- Single-head blowing construction plan
Single-head blowing is the most widely used silt unloading method in Jiangsu, Zhejiang and Shanghai. Build a silt unloading pump ship, place the 350PNS-35 marine silt unloading pump unit and CH350 high-pressure water pump unit in the pump bin, and match the Weichai 6170 450 horsepower and 320 horsepower marine diesel engines. The silt suction pipe and high-pressure water pipe are controlled by hydraulic arms and placed in the silt bin. Through high-pressure water impact, the silt mixture is sucked into the sand suction pipe, and then the silt unloading pump is used to achieve a long-distance transportation task of 1000-1500 meters.
Usually, the unloading work of a 300-cubic-meter silt transport ship can be completed in about 40 minutes. The diesel consumption for each 300-cubic-meter ship unloading sediment is about 40 liters. The pipeline uses an inner diameter of 350, with a rated specific gravity of about 1.15. When transporting 1,500 meters, the flow rate of the solid-liquid mixture is 3.46 m/s.
Single-head blowing is suitable for the loading and unloading of small and medium-sized sediment transport ships, which greatly reduces the use of manpower. One ship only needs two people to operate. This construction plan is relatively mature, and one set of equipment can realize the solution of unloading mud and long-distance transportation of sediment, and can transport sediment to sites tens of kilometers away in series.
- Vertical sand pump unloading solution
2.1 Vertical sand pump is most widely used on sand blowing ships. The vertical sand pump unit is hoisted on the electric hoist. When the sand transport ship approaches, the vertical sand pump is dropped on the sand surface for operation. It mainly uses high-pressure water to impact the sand and water mixture to the pump port of the vertical sand pump, and then uses strong suction to transport the slurry out. Usually, the number of pump units is flexibly selected according to different operation requirements, and the driving mode is motor.
2.2 The biggest advantage of this method of unloading sand is high concentration and high efficiency. The disadvantage is that a large number of sand pumps are used. The vertical sand pump is a medium-speed machine, which wears faster and has a low head. If long-distance transportation is required, a relay pump can be added on the ship. The vertical sand pump is first connected in parallel and then in series to the inlet of the relay pump, and then transported out. If it is near the dock, some customers will also build a sedimentation tank, and then use a horizontal pump to self-absorb and blow the sediment in the sedimentation tank to a distance of one kilometer away.
2.3 According to different construction requirements, users usually choose 6PNSL and 8PNSL pumps from Ocean Pump Industry. Each pump can discharge about 50-100 cubic meters of sand per hour. In the sand blowing and reclamation project in Zhoushan City, Zhejiang Province from 2015 to 2018, each sand blowing ship is equipped with 10 8PNSL vertical sand unloading pumps. A 3,000 cubic meter ship can be blown in about 3 hours. A 400GN-50 marine relay pump is on board to achieve the construction requirement of conveying 1,000 cubic meters of sand per hour at a distance of 1,500 meters. There is also a 600kw generator set and two high-pressure water pumps produced by Ocean Pump Industry on board. The pressure drop is calculated to be 5.45 bar and the flow rate is 4.41 m/s under the premise that the discharge pipe has an inner diameter of 400mm and a specific gravity of about 1.2.
- Excavator (or grab bucket) with ship mud pump mud unloading solution
Some small flat-bottomed mud transport ships have very strong mud viscosity, which cannot be flushed away by ordinary water guns. Many customers will choose to use excavators or grab buckets to dig out the mud and sand, and then design a funnel to pour the mud and sand into the funnel, cooperate with high-pressure water impact and vacuum screen, and then design a mesh plate or grille to keep stones or large particles out, and then add a horizontal mud unloading pump at the bottom of the funnel to realize the extraction and transportation of mud on the ship. Marine mud unloading pumps with different lifts can be selected according to different transportation conditions.
A user in Zhongshan, Guangdong, used this method, using two excavators to work alternately, choosing 400GN-50 with 8170 diesel engine, and then a 14-inch high-pressure water pump. The dry mud extraction volume per hour is 600 cubic meters, the row spacing is 1000 meters, and the row pipe is selected with an inner diameter of 400mm. The fuel consumption of the two units is about 110 liters per hour. Under the premise of specific gravity of about 1.2, the calculated pressure drop is 3.63 bar and the flow rate is 4.41 m/s.
- The method of unloading sediment by open-bottom boat and belt boat
4.1 Open-bottom boat and belt boat usually have self-unloading function, so there is no need to worry about the size of the boat, and you only need to choose different construction plans according to the output.
4.2 The open-bottom boat is to pull up the bottom plate of the boat by iron chain, and after transporting it to the river, loosen the hinge and open the bottom of the boat, so that the sediment in the cabin leaks into the river, so that the sediment transporting boat can drive away and load sand again, and use a jet sand pumping boat to absorb sediment. The advantage of this operation method is that the sand unloading is not limited by time and does not require very close cooperation. A jet sand pumping boat can extract sediment from multiple open-bottom boats at the same time.
4.3 A user in Hepu, Guangxi uses three 100-cubic-meter open-bottom boats and two 10-inch jet boats for cyclic operation. The open-bottom boat is self-priming and self-unloading. The sand pumping capacity is about 80 cubic meters per hour. After unloading to the river bottom, the 10-inch jet boat can extract 100 cubic meters of sand from the bottom of the water in about an hour. Compared with other methods, it is cheaper and more flexible.
4.4 The belt boat is simpler. The customer’s sand boat has a self-unloading function. If the sand on the belt boat needs to be transported over a long distance, a funnel is needed. If the belt boat cannot dock due to draft, a funnel boat needs to be made. The marine sand unloading pump of Ocean Pump Industry is placed at the bottom of the funnel and transported out with the help of a high-pressure water gun. If the belt boat can dock, a funnel is built at the dock, and then the marine sand unloading pump is used in the same way to transport the silt.
4.5 The reclamation project of Kai Tak Airport in Hong Kong uses a belt ship plus a funnel. After the large belt ship docks, a set of hydraulic gates is added to the bottom of the funnel to control the amount of sand, and then the high-pressure water mixed with the silt enters the ZS350 large sand unloading pump. The ZS350 sand unloading pump is equipped with a Weichai 8170 1000 horsepower 1500 rpm diesel engine. The silt conveying distance is 1000 meters. The pipeline uses ultra-high molecular polyethylene pipes, and the sand unloading volume is about 400 cubic meters per hour. The inner diameter of the pipeline is 350mm, the calculated pressure drop is 3.58 bar, and the flow rate is 4.03 m/s.
- Sand unloading method of sand transport ships with pump bunkers
Some sand transport ships have a special ship sand unloading pump bunker at the bottom bunker, which is also controlled by hydraulic top. When the sand ship docks, it is connected to the sand discharge pipeline, and then the bottom is slowly opened. It is also filled with clean water through a high-pressure water pump, and then the ship sand unloading pump is used to transport the sand to the shore.
A large self-unloading sand transporter made by a user in Shantou, Guangdong, uses a 500GN-60 large marine sand unloading pump to unload sand. It can transport 1,000 cubic meters of pure sand per hour over a distance of 2,500 meters. It is equipped with a Cummins 2,400 horsepower diesel engine and a 1260 marine gearbox, and the pipe is 500mm. The calculated pressure drop is 6.21 bar and the flow rate is 4.23 m/s.
- Summary of sediment unloading methods
Sand unloading has been a problem since the start of shipping. From the previous manual handling to the use of mud unloading pumps and sand unloading pumps, it has achieved a great leap. However, if the combination of different pump types can be flexibly used in construction, it will often bring twice the result with half the effort.
The engineer team of Ocean Pump Industry will formulate different silt unloading construction plans according to different forms of silt transport ships in different regions. Small ships are relatively flexible and have more choices. The construction of large silt transport ships usually affects the whole body. Therefore, you must be cautious when choosing and choose a professional team to make a good plan and formulate a construction plan.
- About Taian Ocean Pump Industry
Tai’an Ocean Pump Industry Co., Ltd. (hereinafter referred to as Ocean Pump Industry) is a manufacturer, supplier and exporter of sand pumps, large sand suction pumps, slurry pumps, mud pumps, silt pumps, sewage pumps, dredging pumps, sand pumps and other equipment. The company integrates independent research and development, equipment manufacturing, pre-sales and after-sales services. The company’s business covers sand suction and dredging projects. The products cover 20 series and more than 500 specifications. The products are exported to 36 countries and regions. Ocean Pump Industry has won the praise and trust of users with rich industry experience, professional technology and excellent service.
