1. Fully Submerged Jet Pump

  • A jet pump’s impeller and inlet can be fully underwater.
  • Often used in RC boats, small submarines, or pump systems where the pump is submerged in a tank or body of water.
  • The motor itself may or may not be underwater depending on design:
    • Waterproof motor / sealed housing: Required if the motor is submerged.
    • Above-water motor: Only the impeller/water intake is submerged (common in shallow-water RC boats).

Definition

A jet pump is a type of pump that uses a high-speed jet of fluid (usually water or steam) to entrain and move another fluid.
It has no moving parts in the pumping chamber itself; the energy comes from a motive fluid.


How It Works

  1. A high-pressure fluid (motive fluid) is ejected through a nozzle, creating a high-velocity jet.
  2. The jet creates a low-pressure zone (suction) that draws in the surrounding fluid.
  3. The mixed fluid enters a diffuser or mixing chamber where velocity is converted into pressure.
  4. The combined fluid exits the pump at a higher flow rate.

Diagram Concept (simplified):

Motive fluid → Nozzle → Suction fluid drawn in → Mixing chamber → Outlet

Features

  • No moving parts in the main pump (simple and reliable).
  • Can pump liquids, gases, or even slurries.
  • Can lift water from deep wells or create suction in fluid systems.

Applications

  • Water wells (deep well jet pumps)
  • Marine bilge pumping
  • Boiler feed systems
  • Chemical and industrial processes

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