Tube-to-Tubesheet Joints in Shell and Tube Heat Exchangers

What are Hydraulic Machines? Hydraulic Machines are defined as those machines which convert either hydraulic energy ( energy possessed by water) into mechanical energy ( P.E+K.E) energy into hydraulic EX

• Pumps
• Turbine s

Introduction Centrifugal pumps are used to increase pressure in a liquid for the purpose of transporting the liquid through piping and other devices for use in an industrial  process. With the higher pressure, the liquid can be transported in short or long pipelines for delivery to an ultimate destination. Examples include water pipelines, refined petroleum and crude oil pipelines. The pressure generated by the pump is gradually depleted as the liquid flows through the pipeline, due to friction in the pipe, as well as any elevation increase from the point of origin to the destination point. The liquid as it enters the pump has a certain amount of energy, due to its initial pressure (pressure energy), position (potential energy) and its velocity (kinetic energy). The potential energy depends on the location of the liquid from some datum, such as sea level. The kinetic energy is due to the motion of the liquid. The sum of three components is the total energy of the liquid. As the liquid comes out of the pump, energy is imparted by the rotating element (impeller) in the pump and the liquid pressure increases. The velocity of the liquid also changes from that at the pump inlet. In a centrifugal pump, the liquid is accelerated by centrifugal force during its passage through the rotating pump impeller and, finally at the exit, the kinetic energy is converted to pressure energy as it exits the pump volute into the discharge piping.

The most numerous types of fluid machineries are of the pump family (machines which add energy to the fluid), other important types are turbines (which extract energy from fluid). Both types are usually connected to a rotating shaft, hence also called turbomachineries. The prefix turbo- is a Latin word meaning ―spin’’ or ―whirl,’’ appropriate for rotating devices. The pump is the oldest fluid-energy-transfer device known. At least two designs date before Christ: (i) the undershot-bucket waterwheels, or norias, used in Asia and Africa (1000 B.C.) and (ii) Archimedes’ screw pump (250 B.C.), still being manufactured today to handle solid-liquid mixtures or to raise water from the hold of a ship. Paddlewheel turbines were used by the Romans in 70 B.C., and Babylonian windmills date back to 700 B.C. Since that time, many variations and applications of pumps have been developed. The power generating turbomachines (turbines) decrease the head or energy level of the working fluids passing through them and they are coupled to machines, such as electric generators, pumps, compressors etc.