B. Description of Main parts

     (1)The injection water pump in cast is composed of thefollowing parts: a. Nozzle: b.Suction chambor; c. Mixing chamber; d. diffusero

     (2)ZcuA19Mn2 is used for nozzle, for which hydraulic test must be carried otu after machining ZcuZn16si4 or HT200 can be used for the suetion chamber, mixing chamber and diffuser in easting construction. For them, hydraulic test for cheking strength should also be carried out after machining.

     (3)For stationary injection water pump, its inlet, suction and discharge are all fitted with maiine flanges, For portable injection water pump, marine fire nipple is used for its inlet, suetion and discharge.

C. Operation principle

   Energy transfer in injection water pump depends on fluid collision. Thatis, fluid in high pressure will increase its speed aterflowing through nozzle, and will inject outward in high speed,  thereby decreasing the pressure. This water jet carries away the air at iulet because of the viscons drag between water jet and air so as to creat vacuum there, thereby water is sucked in unber the effect of pressure difference.The water to be sucked is mixed with water jet in high speed and is come into collision with it at the inlet of mixing chamber and then flows into mixing chamber;Thus the speed of Water jet is decreased, while the water to be sucked is increasing its speed.These two speeds will become equal gradually until thcy are mixed with each other porfectlyo At that time, the pressure in mixing chamber is increased graduallyo The mixed water then flows into diffuser. so that the velocity head is converted into pressure head and is discharged out of the diffuser.

    This injection water pump is a solf-ptiming pump and can operate steadiIy and

continuously. The advantage of this pump is simple in mamufacturing and maintennance.

D, Optima nozzle position

    Different flowrates will be produced with different positions. of nozzle even under the same working condition. The position wdere max. flowrale can be produced by nozzle is considered as an optimum nozzle position. the nozzle position shown on drawing is the optimum nozzle position under norminal workihg condition. The optimuum nozzle posltion can be adjusted by increasing or decreasing the number of sheet gaskets between nozzle and pump boby because of the error in manufacturing.