5.1. Heat pipe manufacture processes

The main requirements on the heat pipe production are the high purity of the material of the individual parts and the working substance, as well as their mutual compatibility.

of the heat pipe can be divided into several sub-processes involving mechanical and chemical

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Before heat pipe production, it is necessary to thoroughly clean all components of the heat pipe to avoid any undesirable influence, which could ultimately have an effect on the heat transfer ability reduction. In cleaning process, first, mechanical impurities and rust from the body of the pipe are removed manually and then followed by chemical cleaning of the body, wick

In the mechanical part of the production, the individual components of the heat pipe are first prepared: the body, the filling pipe, the wick structure, and the end caps. All components are then joined together by welding or soldering. In the case of wick heat pipe production, a wick structure is placed in the internal space of the body before to heat pipe closure. The closure of the heat pipe is the connection of the body with the end caps. In Figure 20, the standard types of the heat pipe closure by end caps are shown. The filling pipe is connected to one of the end caps due to the inner space vacuuming. After vacuuming, the heat pipe is filled with the working fluid,

treatment of materials.

• Body production and end caps. • Production of wick structure.

• Cleaning of components.

Technological process of the heat pipe production cycle:

• End caps closure by impervious joints (welding, soldering).

• Vacuuming of inner space and filling with the working fluid.

• Mechanical verification of body strength and tightness.

• Sealing the filling pipe (welding, soldering).

structure, end caps, and filling pipe [36].

5.1.1. Mechanical part of heat pipe manufacture

Figure 20. Types of the heat pipe closure by end caps.

The basis of the heat pipe construction is the pipe body and the working fluid. The production of a heat pipe primarily consists in selecting a suitable material of the pipe and the working fluid. The working fluid is selected according to the temperature conditions in which the heat pipe will be used, because heat flux transferred by the heat pipe depends on the material of the pipe, the working fluid, and their mutual compatibility. An important part of the wick heat pipe is the wick structure, which also has a large impact on the amount of transferred heat flux.

The main components of heat pipe are:


The heat pipe body may be of any cross-section, for example, circular or square, may include mounting flanges for ease of assembly, and may be bent into various shapes. The wick structure can be formed by grooves extruded into a pipe body or fine mesh screen, porous material and artery inserted into the heat pipe body [35]. In Figure 19, a schema of the wick heat pipe construction is shown.

The most common shape of the heat pipe is cylinder, because in addition of easily available product (wide assortment of material and the size of the pipe cross-sections), it provides certain advantages also in terms of strength and thermomechanical parameters. The advantage of producing a cylindrical shaped heat pipe is in the ease handling with the cylindrical material. In practice, heat pipes with a flat rectangular, triangular or other cross sections are also used. The most common heat pipes are manufactured with an inner diameter of 8–25 mm and an internal diameter of 2–5 mm—the so-called micro-heat pipes. The production process

Figure 19. Schema of the wick heat pipe construction.

of the heat pipe can be divided into several sub-processes involving mechanical and chemical treatment of materials.

Technological process of the heat pipe production cycle:


5.1. Heat pipe manufacture processes

160 Porosity - Process, Technologies and Applications

The main components of heat pipe are:

• Pipe body (container)

heat pipe construction is shown.

Figure 19. Schema of the wick heat pipe construction.

• Working fluid • Wick structure

• End caps • Filing pipe

The main requirements on the heat pipe production are the high purity of the material of the

The basis of the heat pipe construction is the pipe body and the working fluid. The production of a heat pipe primarily consists in selecting a suitable material of the pipe and the working fluid. The working fluid is selected according to the temperature conditions in which the heat pipe will be used, because heat flux transferred by the heat pipe depends on the material of the pipe, the working fluid, and their mutual compatibility. An important part of the wick heat pipe is the wick structure, which also has a large impact on the amount of transferred heat flux.

The heat pipe body may be of any cross-section, for example, circular or square, may include mounting flanges for ease of assembly, and may be bent into various shapes. The wick structure can be formed by grooves extruded into a pipe body or fine mesh screen, porous material and artery inserted into the heat pipe body [35]. In Figure 19, a schema of the wick

The most common shape of the heat pipe is cylinder, because in addition of easily available product (wide assortment of material and the size of the pipe cross-sections), it provides certain advantages also in terms of strength and thermomechanical parameters. The advantage of producing a cylindrical shaped heat pipe is in the ease handling with the cylindrical material. In practice, heat pipes with a flat rectangular, triangular or other cross sections are also used. The most common heat pipes are manufactured with an inner diameter of 8–25 mm and an internal diameter of 2–5 mm—the so-called micro-heat pipes. The production process

individual parts and the working substance, as well as their mutual compatibility.


Before heat pipe production, it is necessary to thoroughly clean all components of the heat pipe to avoid any undesirable influence, which could ultimately have an effect on the heat transfer ability reduction. In cleaning process, first, mechanical impurities and rust from the body of the pipe are removed manually and then followed by chemical cleaning of the body, wick structure, end caps, and filling pipe [36].
