The difference between submersible pumps and underwater pumps

It is recommended to read the book \"Manual for Selecting Industrial Pumps\", published by the Chemical Industry Press

　Submersible pump: Before starting the pump, the suction pipe and the inside of the pump must be filled with liquid. After the pump is started, the impeller rotates at high speed; the liquid inside rotates along with the blades. Under the effect of centrifugal force, the liquid is ejected outward from the impeller. As it moves through the diffusion chamber in the pump casing, its velocity gradually decreases while its pressure increases, before it finally flows out through the pump outlet and the discharge pipe. At this point, a vacuum low-pressure area devoid of both air and liquid is formed at the center of the blade as the liquid is flung outward. Under the effect of the atmospheric pressure at the surface of the liquid pool, the liquid flows into the pump through the suction pipe; in this way, the liquid is continuously drawn up from the pool and then continuously discharged through the outlet pipe. A water treatment tool with a very wide range of uses. Unlike ordinary pumps, it operates underwater, whereas most pumps work on the ground. The components of the submersible pump that come into contact with the medium are made of phenolic glass fiber reinforced with polyvinyl butyral, formed through high-temperature molding. The connection pipes and liquid outlet pipes are made of phenolic glass fiber tubes produced using a semi-dry winding process. The impeller shaft sleeves are bonded to the pump shaft using phenolic putty. All parts of the submersible pump that are submerged are bonded together with phenolic putty; as a result, no metal comes into contact with the medium, ensuring excellent corrosion resistance. This product boasts advantages such as light weight, high strength, resistance to deformation, heat resistance, and corrosion resistance. In terms of corrosion protection, it can partially replace expensive metals such as aluminum-containing stainless steel, iron, and titanium alloys. 　　Transmission and rotation direction of the submersible pump: The pump is directly driven by an electric motor through a claw-type elastic coupling, and when viewed from the side of the motor, the pump rotates in a clockwise direction.

All submersible pumps are filled with water; only the filter and some of the pipes of the submersible pump are filled with water

Is there a more professional explanation? Or is there another concept: deep well pumps? Are there any connections or differences between these two concepts?

Submersible pumps are inexpensive, but they are not suitable for high-power motors; moreover, the waterproofing of the motor is a significant issue. Submerged pumps are mostly used in industrial applications and can operate at high power levels.

Deep well pumps operate on the same principle as submersible pumps: the entire pump is placed underwater, the motor needs to be waterproof, and the other requirements are relatively simple

The return pipe details aren’t clear; I can’t understand it. 7# gsm0001g

A submersible pump is a pump as a whole that includes the motor and operates underwater; only the pump body and some pipes are submerged, while the motor and coupling remain on the surface

In submersible pumps, both the pump body and the motor are submerged in the liquid, while in submerged pumps only the pump body is submerged in the liquid, with the motor remaining outside the liquid; this is the main difference

The motor of the submersible pump is located outside; when selecting the motor, it is necessary to consider whether it is to be used in an explosion-proof area