In mold temperature control systems, the shell-and-tube heat exchanger operates as follows:

Two fluids:

Shell Side: Heat transfer medium (hot oil or hot water from the mold circulation system).

Tube Side: Heating or cooling medium.

Heating: Typically steam or high-temperature thermal oil.

Cooling: Typically cooling water (from cooling towers or chillers).

Operating Modes:

Heating Mode: When the mold requires temperature increase, steam (or high-temperature thermal oil) is introduced into the tubes to heat the lower-temperature heat transfer medium flowing in the shell side, which returns from the mold. After heating, the heat transfer medium is pumped back to the mold by the circulation pump to heat the mold.

Cooling Mode: When mold cooling is required (to prevent product deformation and shorten cycle time), cooling water is introduced into the pipes to absorb heat from the higher-temperature heat transfer medium flowing in the shell side and returning from the mold. After cooling, the heat transfer medium is pumped back to the mold to reduce its temperature.

Dynamic Control: A high-quality temperature control system dynamically switches or adjusts the flow rates of steam and cooling water based on setpoints, enabling precise and stable mold temperature control.

Medium Selection:

Water as Heat Transfer Medium: Used for applications with lower temperature requirements (<120°C), offering low cost. However, prevention of scaling and corrosion is essential.

Thermal Oil as Heat Transfer Medium: Used for high-temperature applications (>120°C up to 300°C+), less prone to scaling but requires attention to aging issues.

Scaling Issues:

Using ordinary tap water or hard water as the cooling medium can cause scaling on pipe walls, significantly reducing heat transfer efficiency. Softened water or closed-loop cooling water is recommended.

System Integration:

This heat exchanger is an integral part of the mold temperature control unit. Its performance depends on seamless coordination with components such as circulation pumps, control systems, and valves.