In jet condensers the exhaust steam and cooling water come in direct contact with each other whereas as in surface condensers they don’t mix with each other.
The temperature of cooling water and the condensate is same in jet condensers when leaving the condensers.
Elements found in the jet condenser are as follows:
- Nozzles or distributors for the condensing water.
- Steam inlet.
- Mixing chambers: They may be two types
(a) parallel flow type
(b) counter flow type
depending on whether the steam and cooling water flow in the same direction or opposite direction.
- Hot well.
In jet condensers the condensing water is called injection water.
Types of Jet Condensers:
Jet condensers can be classified into three types and are discussed below with schematic diagrams of each condenser type.
1. Low level jet condenser (Parallel flow type):
In low level jet condenser (Fig. 1) water is sprayed through jets and it mixes with exhaust 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 direction.
2. High level jet condenser (Barometric condenser):
In high-level jet condenser (Fig. 2) the condenser shell is placed at a height nearly 10 m (barometric height) above the hot well. Barometric condenser doesn’t flood the engine if the water extraction pump fails. A separate air pump is used to remove the air.
3. Ejector Condenser:
In ejector condenser (Fig. 3) cold water is exhausted under a head of about 5 to 6 m through a series of convergent nozzles. The steam and air enter the condenser through a non-return valve. Mixing with cool water condenses the steam. During this mixing pressure energy is partly converted into kinetic energy at the converging cones and the diverging cones the kinetic energy is partly converted into pressure energy. Inside higher pressure higher is achieved than atmospheric pressure so as to discharge the condensate to the hot well.