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Double Pipe Heat Exchangers Applications Advantages}

Tuesday, June 13th, 2017

Submitted by: Jeyakumar J

Double pipe heat exchanger designing is look direct focus in design methods. It uses one heat exchanger pipe inside another. After determine as our requirements the heat exchanger surface area, for either counte

flow or parallel flow, the pipe sizes and number of bends for the double pipe heat exchanger can be selected.It having main factor to focus on the flow of the type of double pipe heat exchanger design A double pipe

heat exchanger will systematically its be either counterflow or parallel flow. Crossflow just doesn’t work for a double pipe heat exchanger. The flow pattern and the required heat exchange duty allows calculation of

the log mean temperature difference. That together with an estimated overall heat transfer coefficient allows calculation of the required heat transfer surface area. Then pipe sizes, pipe lengths and number of bends

can be determined.Double pipe heat exchangers are normally designed in a hairpin shape and are fabricated in accordance with ASME Code.

In double pipe heat exchanger design, the main factor is that create flow pattern in heat exchanger. A double pipe heat exchanger will specifically by either counterflow or parallel flow. Crossflow just doesn’t

work for a double pipe heat exchanger. The two equation numerical model has been applied for parallel flow double-pipeheatexchanger filled with open cell metal foams. Areas and conditions for the most useful

application of double and multitube exchangers are outlined. Calculation methods are presented for plain double pipe units.The design a double pipe heat exchanger (also known as a concentric tube heat exchanger).

Double pipe heat exchangers are often used in the chemical, food processing and oil & gas industries. They have a particular advantage when close temperature approaches are needed or in high pressure applications.

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Double pipe exchangers are divided into two major types:

1. Single-tube

2. Multi-tube.

The Single-tube type consists of a single tube or pipe, either finned or bare, inside a shell. Double-pipe sections permit true counter-current or true co-current flow, which may be of particular advantage when very

close temperature approaches or very long temperature ranges are required. Multiple tube double pipe sections contain from 7 to 64 tubes, bare or longitudinally finned, within the outer pipe shell. Normally,its

having only to bare tubes are used in sections containing more than 19 tubes.

Double-pipe units are well suited for high pressure applications because of their relatively small diameters. This allows the use of small flanges and thin wall sections, as compared to conventional shell and tube

equipment. The use of fin tubes in double pipe sections are normally economical if the annular heat transfer coefficient is less than 75% of the tube side coefficient. The fin efficiency increases with decreasing

annular coefficient and increasing fin thermal conductivity. In addition, shorter fins have higher fin efficiencies.

Double Pipe Heat Exchanger Applications:

1. Pasteurization

2. Digester heating

3. Heat recovery

4. Pre-heating

5. Effluent cooling.

Double Pipe Heat Exchanger Advantages:

1. Double pipe heat exchanger consists of two concentric pipes are hot fluid ,cold fluid.

2. Economically adaptable to service differentials.?Ideal for wide temperature ranges and differentials.

3. Provides shorter deliveries than shell and tube due tostandardization of design and construction.

4. Operates in true counter current flow permittingextreme temperature cross.

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