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Analysis for the installation of suction and discharge of th
Source:未知|Popularity:0|release date:2020-03-13 13:36:34
It is very important to install the suction and discharge of horizontal multistage pump in site. If the installation is not reasonable, it will affect the pump and even the whole system. The installation of inlet and outlet pipelines has an important impact on the operation and service life of the pump, so the installation must be carried out carefully.
1. Requirements for foundation and pipeline installation
It is suggested that the users employ professionals to design the foundation, pipeline and install the multistage pump.
1.1. The foundation must be firm and able to absorb the vibration of the pump and support the unit permanently. The foundation must be sufficient to support 2 times of the unit weight (including the motor). Generally, reinforced concrete is used as the foundation. Anchor bolt holes shall be reserved in advance on the foundation. When installing the water pump, the anchor bolts shall be placed before the secondary grouting.
1.2. Do not use the inlet and outlet of the pump as the pipe support, and all pipes shall be supported independently; the outlet pipe is generally one size larger than the pump outlet; the installation height of the inlet pipe must meet the calculation value, and the elbows on the inlet and outlet pipes shall be reduced as much as possible to avoid excessive loss, and ensure that the NPSHr is not exceeded when the pump is working; gate valve shall be installed between the outlet pipe and the check valve, gate valve inner diameter shall not be less than pipe inner diameter.
In our actual work, we have encountered such a situation. Once, when the user installed the inlet and outlet pipelines of the pump, the user was anxious to put the pump into operation after the pump arrived at the site because of the pipes already ordered. Later, the technicians who did not consult the pump manufacturer but directly installed the inlet and outlet pipes of the pump as their own ideas. As a result, when the pump was started, there was abnormal noise, insufficient flow at the outlet, and the noise of the inlet pipe. Then start to cause a series of problems such as pump vibration. Later, the user called the pump supplier and found the following problems through the communication between the technical personnel of the pump manufacturer and the on-site telephone:
1. The diameter of the inlet pipe is smaller than that of the pump;
2. There is air leakage at the seal between the inlet pipeline and the pump;
3. The inlet pipeline is not supported completely by the inlet pipeline of the pump, which causes the inlet flange of the pump to be slightly skewed and warped;
4. Because the outlet pipe needs to be made into a reducer, the user directly makes a pipe to weld at will. The stress concentration of the matching counter flange of the pump causes cracks;
5. The valve installation position on the outlet pipeline is unreasonable.
Tell the other party the solution immediately after knowing these situations:
1. Replace the inlet pipeline.
2. To install the pipeline, do the pressure test to the pump pipeline to check the air tightness or slightly tighten the nut at the joint of sealing surface.
3. A support frame is added on the inlet pipeline of the pump to ensure that the load of the pipeline itself is borne by the pipeline.
4. It is suggested that the user should measure the size of the outlet pipe, or make a big and small end to match it, or use the expansion joint of the big and small end to solve this problem.
5. The outlet pipeline of the multistage pump is connected with a straight pipe first, then with a check valve, and finally with a gate valve.
At last, after the user finishes installation step by step according to the supplier's method, the pump can be started up and run normally and stably.
1. Requirements for foundation and pipeline installation
It is suggested that the users employ professionals to design the foundation, pipeline and install the multistage pump.
1.1. The foundation must be firm and able to absorb the vibration of the pump and support the unit permanently. The foundation must be sufficient to support 2 times of the unit weight (including the motor). Generally, reinforced concrete is used as the foundation. Anchor bolt holes shall be reserved in advance on the foundation. When installing the water pump, the anchor bolts shall be placed before the secondary grouting.
1.2. Do not use the inlet and outlet of the pump as the pipe support, and all pipes shall be supported independently; the outlet pipe is generally one size larger than the pump outlet; the installation height of the inlet pipe must meet the calculation value, and the elbows on the inlet and outlet pipes shall be reduced as much as possible to avoid excessive loss, and ensure that the NPSHr is not exceeded when the pump is working; gate valve shall be installed between the outlet pipe and the check valve, gate valve inner diameter shall not be less than pipe inner diameter.
In our actual work, we have encountered such a situation. Once, when the user installed the inlet and outlet pipelines of the pump, the user was anxious to put the pump into operation after the pump arrived at the site because of the pipes already ordered. Later, the technicians who did not consult the pump manufacturer but directly installed the inlet and outlet pipes of the pump as their own ideas. As a result, when the pump was started, there was abnormal noise, insufficient flow at the outlet, and the noise of the inlet pipe. Then start to cause a series of problems such as pump vibration. Later, the user called the pump supplier and found the following problems through the communication between the technical personnel of the pump manufacturer and the on-site telephone:
1. The diameter of the inlet pipe is smaller than that of the pump;
2. There is air leakage at the seal between the inlet pipeline and the pump;
3. The inlet pipeline is not supported completely by the inlet pipeline of the pump, which causes the inlet flange of the pump to be slightly skewed and warped;
4. Because the outlet pipe needs to be made into a reducer, the user directly makes a pipe to weld at will. The stress concentration of the matching counter flange of the pump causes cracks;
5. The valve installation position on the outlet pipeline is unreasonable.
Tell the other party the solution immediately after knowing these situations:
1. Replace the inlet pipeline.
2. To install the pipeline, do the pressure test to the pump pipeline to check the air tightness or slightly tighten the nut at the joint of sealing surface.
3. A support frame is added on the inlet pipeline of the pump to ensure that the load of the pipeline itself is borne by the pipeline.
4. It is suggested that the user should measure the size of the outlet pipe, or make a big and small end to match it, or use the expansion joint of the big and small end to solve this problem.
5. The outlet pipeline of the multistage pump is connected with a straight pipe first, then with a check valve, and finally with a gate valve.
At last, after the user finishes installation step by step according to the supplier's method, the pump can be started up and run normally and stably.