In some cases you may want slower flow, and special systems are available for these situations.

For example, you may have a mold that runs only if the cores are a few degrees warmer than the cavities, or vice versa. To warm up the desired zone, you merely throttle the cooling flow. A fancy name for this is heat recovery temperature control. In other words, you recover heat from the molding process to elevate the mold temperature. You may have noticed that it is very difficult to settle a mold into a steady-state condition. You’re always chasing the temperature up and down. If you are ambitious, you might hook up a mold heater to solve the problem. But there is an easier way. Heat recovery temperature control systems are available that electronically monitor cooling circuit temperature and automatically throttle flow to maintain a set temperature.

The temperature sensor is normally placed in the water return from the mold but can even be placed in the mold steel. This system will not replace a mold heater in situations that require adding heat from outside the mold — when the mold must be hot before you can start molding, for example. But it can make life easier when different zones require slightly different temperatures or when you want to run a mold warmer than tower or chiller water allows at full flow. These systems allow you to throttle the flow with precise temperature control. With their modest initial cost and operating energy savings, heat recovery systems can be an attractive alternative to traditional mold heating systems.