Water eductors are pumps without moving parts, driven by pressurized water. The water eductor pump is based on the fact that a water-jet entrains the surrounding liquid. When this jet is placed inside a duct it can be used to create a substantial vacuum, and with proper design of the duct most of the energy in the mixing jet can be regained as static pressure on the discharge side. Because water eductors are extremely simple and robust they are very suitable for a large range of marine applications. advantages: When a motive pump is available, the initial and operating costs of water eductors are very low. The installation is simple, and since they contain no moving parts, the reliability is high. Water eductors are always self-priming and can produce an almost absolute vacuum. Water eductors are not virtually choked and handle particles and fibers very well.
Air ejector type priming unit is a kind of Automatic Pump Priming Water Supply Equipment, and it is used by being attached to medium and large-sized pumps mainly. If the inside of a pump body is not filled with fluid at the first stage to operate the pump, the Pump may not suck in fluid at idle. It is said that the fluid which must be filled in the pump is Priming Water. The larger the size of the air ejector type pump is, the more it is impossible to reinforce human power due to Priming Water along the setup place. Therefore, self priming equipment is used.