In jet condensers the exhaust steam and cooling water come in direct contact with each other. The temperature of cooling water and the condensate is same when leaving the condensers. Elements of the jet condenser are as follows:
Nozzles or distributors for the condensing water.
Mixing chambers: They may be (a) parallel flow type (b) counter flow type depending on whether the steam and water move in the same direction before condensation or whether the flows are opposite.
In jet condensers the condensing water is called injection water.
TYPES OF JET CONDENSERS
1.Low level jet condensers (Parallel flow type). In this condenser (Fig. 1.13) water is sprayed through jets and it mixes with steam. The air is removed at the top by an air pump. In counter flow type of condenser the cooling water flows in the downward direction and the steam to be condensed moves upward.
2. High level or Barometric condenser. Fig. 1.14 shows a high-level jet condenser. The con-denser shell is placed at a height of 10.33 m (barometric height) above the hot well. As compared to low level jet condenser. This condenser does not flood the engine if the water extraction pump fails. A separate air pump is used to remove the air.
Ejector Condenser. Fig. 1.15 shows an ejector condenser. In this condenser cold water is discharged under a head of about 5 to 6 m through a series of convergent nozzles. The steam and air en-ter the condenser through a non-return valve. Mix-ing with water condenses steam. Pressure energy is partly convert into kinetic energy at the converging cones. In the diverging come the kinetic energy is partly converted into pressure energy and a pressure higher than atmospheric pressure is achieved so as to discharge the condensate to the hot well.