Heat Exchanger Products

Amongst others we provide the following heat exchanger products:

• Air & Water-Cooled Heat Exchangers
• Oil Coolers
• Steam Heaters
• Tube Bundles
• U-Tube Bundles
• Shells & Water boxes

Shell and tube heat exchanger

Shell and tube heat exchangers consist of two components: the outer shell and in the inner tube bundle. The shell side has an inlet and outlet flow which regulates the fluid that requires cooling or heating. The tube bundle contains the set of tubes which are nested in a specific pattern and control the flow of the fluid that either cools or heat the fluid on the Shell side. The shell side fluid runs over the tubes that are being heated or cooled so that it can either provide the heat or absorb the heat required. The tube bundle and can be made up of several types of tubes: plain, longitudinally finned, etc. Copper tubes are generally used because of its high heat transfer properties. The flow of the shell side fluid which runs over the tubes is controlled by baffle plates.

There are several design features that are taken into consideration when designing the shell and tube heat exchangers and includes the following:

Tube diameter: To minimise tube cleaning (fouling) problems, larger tube diameters can be used. Therefore determining the tube diameter, the available space, cost and the fouling properties of the fluids must be considered.

Tube thickness: The wall thickness of the tubes usually determines the following:

• Sufficient room for corrosion
• Providing enough resistance for the fluid flow vibrations
• Axial strength
• Availability of spare tubes from suppliers in the event of an emergency repairs
• Withstanding internal and external tube pressures
• There is an aim to design the heat exchanger as long as physically possible without exceeding production capabilities. Limitations do however exist and includes the following:
• The space available at the site where it is going to be used
• Note that long thin tubes are difficult to take out and replace

Tube pitch (the centre to centre distance of two tubes): It is good practice to ensure that the tube pitch is not less than 1.25 times the tubes' outside diameter. A larger tube pitch leads to a larger overall shell diameter which tends to be more expensive.

Tube corrugation: this type of tubes, mainly used for the inner tubes, increases the turbulence of the fluids and the effect is very important in the heat transfer giving a better performance.

Tube Layout: Refers to the pattern of the tubes in the tube plates and how the tubes are positioned within the shell. The main types of tube layouts are:

• Triangular (30°),
• Rotated triangular (60°),
• Square (90°) and
• Rotated square (45°). The triangular patterns give greater heat transfer as they force the fluid to flow more turbulent over the outside tubes. Square patterns designs are used where high fouling is experienced and which requires regular cleaning.

Baffle Design: baffles are used in shell and tube heat exchangers to direct fluid across the tube bundle. They run perpendicularly to the shell and hold the bundle, preventing the tubes from sagging over a long length and prevent the tubes from vibrating. Baffles should be spaced with consideration for the conversion of pressure drop and heat transfer. Baffles which are spaced too closely cause a greater drop in pressure because of flow redirection. Consequently, baffles which are spaced too far apart means that there may be cooler spots in the corners between baffles.

Heat Exchanger Tubes:

Spiral wound heat exchanger copper tubes

At the heart of our heat exchanger manufacturing business, is our spiral wound copper tube manufacturing process, which produces copper tubes with a 7mm and 9mm copper fin. The spiral wound copper tube Finning machines have been developed over a period of 18 months to perfection. Spiral wound copper finned tubes are used in our air heat exchanger products and have two distinct advantages over extruded copper tubes:

Oval Copper Tube with rectangular Copper Fins

Oval Copper Tubes are manufactured with a rectangular copper fin, which significantly increase the heat transfer surface area around the oval tube.