Install a new centrifugal pump? After carefully selecting the appropriate size and material, make sure to install the new pump correctly to ensure a successful installation. It is important to set the base correctly and align the injection pump machine. It is also very important to complete the piping of the pump correctly.
When setting up a new installation, the piping design of the pump is sometimes overlooked. The focus is more on the equipment rather than the pipeline that supplies the equipment. However, if the pump is installed in an improper piping arrangement, premature and repeated failures may occur during the life of the pump. The maintenance team will repair the pump regularly to effectively treat the symptoms rather than the real problem.
1. Keep the suction pipe as short as possible
It includes a straight pipe whose length is equal to 5 to 10 times the pipe diameter between the pump inlet and any obstacles in the suction line. Note: Obstacles include valves, elbows, "three links", etc.
Keep the pump suction line short to ensure that the inlet pressure drop is as low as possible. The straight pipe provides you with a uniform velocity across the entire pipe diameter at the pump inlet. Both are important to get the best suction power.
2. The diameter of the pipe on the suction side should be equal to or greater than a size of the pump inlet
Pipeline sizing is a balance between cost and friction loss. Larger pipes are more costly, while smaller pipes will bring greater friction losses to the system. In terms of diameter, the discharge pipe diameter should usually match the discharge flange on the pump, but it can be larger to reduce friction loss and reduce system pressure. On the suction side, the diameter can be the same size, but engineers often choose one or two larger sizes, so an eccentric diameter reducer is required. If the viscosity of the liquid is greater than that of water, it is usually best to use a larger suction pipe on the suction side. This also helps to produce uniform pump flow and avoid cavitation.
3. Use an eccentric reducer on the suction side
When the pipe size needs to be changed, please consider using an eccentric reducer on the suction side of the pump. When fluid flows from below the pump, install the flat side of the reducer on the top. If the fluid flows from the top, the flat part of the reducer should be installed at the bottom of the pipe. The flat part is designed to prevent air pockets from forming at the pump suction.
4. Eliminate the elbow installed on or near the pump inlet nozzle
Include a straight pipe diameter of 5 to 10 between the pump inlet and the elbow. This helps eliminate the "side load" of the pump impeller and produces uniform pump axial bearing load.
5. Eliminate the air entrainment potential in the suction duct
Maintain a sufficient liquid level in the air supply tank to eliminate the formation of vortex and air retention.
Avoid high pockets in the suction pipe to avoid accumulation of air
Under the condition of suction, keep all pipes and joints tightly connected to prevent air from entering the pump.
6. Make sure that the piping arrangement does not cause strain on the pump casing
The pump must not support the suction or discharge piping. Any stress on the pump casing from the piping system will greatly shorten the life and performance of the pump.
Remember that improving pump performance will help compensate for piping errors that occur on the discharge side of the pump. However, suction problems may be the root cause of repetitive failures, and if not solved properly, they may cause problems for many years. Problems with the suction side piping cause most pump problems.
Piping design is an area where basic principles are often overlooked, which can lead to increased vibration and premature failure of seals and bearings. For a long time, due to many other reasons that these equipment may fail, incorrect pipelines have long been ignored as the cause of these failures. Many experienced engineers may argue that pumps with incorrect piping can still operate normally. Although this argument is valid, it cannot make the suspicious pipeline practice correct.