Water Temperature Control Units

Water Temperature Control Units

Water-based mold temperature control units use water as the temperature control fluid and hold the mold temperature constant in the 90 – 160 °C range. The heat transfer coefficient of water is noticeably higher than that of oil; this means the mold responds faster to a change in temperature and that fluctuations within the cycle are balanced out more quickly.

The pressurized water principle

Water boils at 100 °C at atmospheric pressure. For mold temperatures above 100 °C the system is operated under pressure: as the pressure rises, the boiling point of water rises and the water can be carried in the liquid phase up to 140 – 160 °C. For that reason models above 100 °C are called pressurized water (Druckwasser) units and have a closed circuit with pressure safety.

WDC — the direct cooling system

In WDC (Water Direct Cooling) models the cooling water is managed so that it mixes directly into the circuit, rather than through a heat exchanger. This design provides a much faster response in lowering the temperature; it is particularly advantageous in applications that have to change temperature within the cycle (variotherm approaches, fast mold changes).

In which case is water preferred?

• If the target mold temperature is below 160 °C — almost all standard injection molding applications are in this range
• If fast response and a narrow temperature tolerance are required
• If ease of maintenance and a low running cost matter (no oil change, no monitoring of seals)
• In environments with a sensitivity to cleanliness, such as food and medical production

The only disadvantage of water is scale and corrosion; with a closed circuit, suitable water quality and regular checks this problem disappears.

Series

For applications above 160 °C see the oil-based mold temperature control units. For general information: Mold Temperature Control Units