After using the pump coupling device, it is convenient to install and repair. If there is no pump coupling device, the fixed installation. If there is a pump failure, the inspectors need to screw down the screw, lift the pump for inspection, or use other small pumps to pump water down for inspection. If the water quality is dirty, it is difficult for people to go down. At this time, the inspection and repair will encounter trouble, but installing GAK submersible pump. After the coupling device, when it needs to be lifted, people can lift the pump directly without screwing the screw. After the maintenance, the seal between the pump and the pipeline can be realized by following the guide rail, so that the pump can run normally.