What is Shell and Tube Heat Exchanger?


 A heat exchanger is a mechanical equipment that transfers heat between two liquids (i.e., liquids, vapors, or gases) at different temperatures. Depending on the type of heat exchanger used, the heat transfer process from gas to gas, liquid to gas or liquid to liquid can take place via a solids separator in order to avoid mixing and contact of the liquid, e.g., materials and construction components, heat transfer mechanisms and flow configurations also help classify the types of heat exchangers available.

Shell and Tube Heat Exchanger 

Shell and tube heat exchangers can transfer large amounts of heat at relatively low cost and with a serviceable design. You can provide a range of effective piping surfaces while minimizing footprint, fluid volume, and weight.

Fixed Tube Sheet, 2-Pass Heat Exchanger

Shell and tube heat exchanger is available in various design. These have been employed in industry for over 150 years, modern, competitive manufacturers have clearly defined and applied thermal technology and manufacturing methods.

Tube surfaces from standard metals to special metals with normal or improved surface properties are widespread. These helps provide the most cost-effective mechanical design for the associated flows, fluids, and temperatures.

The shell is planned to prevent the liquid flowing in the tube from mixing with the liquid outside the tube. The tube plate can be attached to the housing, but it can also be stretched and contracted by thermal loading by floating the tube plate in the housing or by using a telescopic bellows in the housing. 

Th shell and tube heat exchanger also has a tie rod which maintain the pitch of the desired deflector. This construction also makes it possible to remove the entire tube bundle assembly from the jacket in order to clean the heat exchanger jacket circuit.

Heat Exchanger Parts

SHELL

 SHELL is an integral part of the heat exchanger. It is designed according to the internal pressure. Its diameter is larger than the diameter of the tube sheet. Both sides are closed with flanges or welding heads. It's made of metal.

Tube

The tube is the second component that transports hot or cold liquids. Determine the total number of pipes according to your requirements. There are several standard tubes on the market. The MOC is selected according to the shell, tube and plate material to avoid galvanic corrosion.

Most of the hot liquid is retained on the side of the pipe to maximize its heat and avoid heat loss.

The tubes spacing have two types: squares for highly corrosive materials and triangles for transparent materials.

Tube Sheet 

The tube sheet installs on both sides of heat exchanger. The pipe is attached to it. With the fixed pipe, the heat exchanger tube plate is fixed and cannot be dismantled. The floating pipe enables the exchanger to be dismantled and cleaned.

Baffles 

They are employed in heat exchangers to increase the fluid turbulence on the shell side and thus to increase the heat transfer coefficient. It also supports the pipe and holds it in place. Various types of baffle arrangements are available.

  1. Disc and donut shaped baffles

  2. Aperture deflector

  3. Segmented deflector (most popular)

The aperture distance is just the distance between the two apertures and has a direct influence on the heat transfer coefficient and the pressure drop and should be determined carefully.

Tie Rod

The tie rod is the same tube that is used to hold the joint. One end of the tie rod is attached to the tube seat and the other end to the last deflector (holding the deflector components together, on the tie rod between each deflector to maintain the pitch of the selected deflector. Spacers are attached. Minimum tie rod size and spacers depend on the diameter of the Housing and the dimensions of the tie rods and spacers.

Spacer 

The spacer attaches to the tie rod, holds the deflector in place and prevents vibrations.