Header Tank Heat Exchangers

A heat exchanger is a device for transferring heat energy from a liquid or gas, to another liquid or gas without the two ever coming into contact with each other. A typical shell and tube heat exchanger will contain a tube bundle inside an outer shell, or body. Cold water flows through these tubes, whilst hot water, or gas flows around the outside of the tubes, enabling the heat from the hot water or gas to be transferred to the colder water inside the tubes.

A good example of how the process works are swimming pools, where most are heated via a boiler, using Gas, LPG or Biomass as the energy source. In theory, the most efficient way to heat the pool would be to circulate the pool water directly through the boiler. But were this to happen, the chemicals used in the pool water to keep it safe for use, would quickly corrode and damage vital parts inside the boiler, leading to premature failure and a costly replacement.

However, by using a heat exchanger to act as an ‘interface’ between the boiler water circuit and the pool water circuit, the boiler is protected from damage and the pool water is quickly heated up to the required temperature; the pool water passing through the central ‘tube core’, whilst the hot boiler water circulates around the outside of the tubes, transferring heat energy to the pool water.

More examples of applications where Bowman heat exchangers are used.

During the course of its operating life, a shell and tube heat exchanger will need cleaning many times. Both fresh water and sea water cooling media today contain high levels of minerals and pollutants, which can build up over time, restricting the water flow through the tube core, resulting in a reduced flow rate and significantly lower heat transfer efficiency.

The good news is that Bowman shell and tube heat exchangers are much easier to clean than many other types and the following information is intended as a basic guide:

1. Removing the end covers gives access to the tube core, which can be removed from the body (or shell).
2. The tube plates and external tubes can then be washed using a handheld hose or lance. A steam cleaner can also be used, if available.
3. Small diameter rods or tube brushes can be used to clean through each tube to remove any stubborn deposits.
4. Detergents or chemicals can be used, if tube fouling is severe. Allow plenty of time for the cleaning media to work before hosing down with plenty of water. NOTE: it is important to check any cleaners being used are compatible with the tube material.
5. Thoroughly flush the tube core with clean water to remove all traces of cleaning chemicals/detergents and if necessary, neutralise the cleaning fluid.
6. Reassemble the tube core into the body, refit the end covers in their original orientation and tighten to the recommended torque figures – NOTE: always use new ‘O’ seals after cleaning to ensure a watertight joint.

For more detailed information on care and maintenance of your Bowman heat exchanger or oil cooler, download a copy of our ‘Installation, Operation & Maintenance guide’.

Many water cooled internal combustion engines (ICE), can be adequately cooled, simply by pumping the engines coolant through an air cooled radiator.

Cooler ambient air is drawn into and through the radiator by a cooling fan, transferring heat from the engine coolant as it is pumped through the radiator.

But there are applications where air cooling is either less efficient or not an option for an ICE. This could be due to insufficient air flow, or ambient air temperatures being too high, and in these situations, water cooling is a proven solution.  Moreover, replacing the radiator with water cooled heat exchangers can save valuable space and considerably reduce noise.

Installing water cooling is quite straightforward as instead of a radiator, a heat exchanger, usually of ‘shell and tube’ design, is installed into the engines cooling system.

The heat exchanger has two circuits; one will be connected to the engines cooling circuit and the other connected to a source of cool water, which could be seawater for a marine engine or fresh water for applications such as irrigation systems, power generation, fire protection or automotive engine testing.

The cooling water is pumped through a central tube core in the heat exchanger, whilst the engines coolant flows over and around the outside of the tubes, transferring heat from the engines coolant circuit to the cooling water as it flows through the unit.

Whilst there are many heat exchangers suitable for cooling engines, Bowman’s Header Tank units are particularly successful due to the design, which incorporates and integral expansion chamber above the tube core. This eliminates the problem of air pockets or air locks getting into the cooling stream. There is also has a special de-aeration feature, plus pressurised filler cap, making integration very much easier. For more information on Bowman Header Tank Heat Exchangers