A cooling tower is an installation that retreats heat from water by evaporation or conduction.
The industries use cooling water in various processes. As a result, there are also various types of cooling towers. There are cooling towers that create process water that can only be used once, before it is discharged. There are also cooling towers that create water that can be reintoduced in the production process.

Freshwater or central cooling system: Fresh water is used in a closed circuit to cool down the engine room machinery. The fresh water returning from the heat exchanger after cooling the machinery is further cooled by sea water in a sea-water cooler.
As discussed above, in the central cooling system, all the working machinery on ships are cooled down using circulating fresh water. This system comprises of three different circuits

As discussed above, in the central cooling system, all the working machinery on ships are cooled down using circulating fresh water. This system comprises of three different circuits

The most common central cooling system is a split system, which includes an outdoor cabinet containing a condenser coil and compressor, and an indoor evaporator coil, usually installed in conjunction with your furnace or air handler. The compressor pumps a chemical called refrigerant through the system.
emperature control of the process can be affected using electric, pneumatic, electro-pneumatic and self-acting controls. This Module details some common applications including process vessels, heat exchangers and high temperature fail safe control.
Plastics

Plastics

The logistics behind every single manufacturing project can be an enormous headache if we don’t take the proper time to plan for each step. As it happens, one of the most critical moments in a production cycle is the cooling of the machine and the molds used on it. Cooling takes a lot of time in the production cycle. It makes sense to put a little effort into optimizing the impacts it has on the overall production rate. It is important to remember those cooling systems are necessary to reduce any wear and tear on a plastic injection mold.

Cooling is a process that happens in the middle part of a production cycle. It happens right after the molten plastic injection and just before the ejection of the finished piece. The main objective of the cooling phase is to bring down the temperature of the plastic from 260°C to a more manageable 60º C when the material is fed on the mold. This is supposed to prevent the resins from melting too quickly. It also helps to keep a balanced quality of hydraulic fluid in case of overheating while avoiding excessive viscosity to keep the machine running as silk.

For most modern plastic injection molding machines, the cooling systems are air-powered, with a few still working with the water-based system. Both systems can be centralized, portable, or customized to the requirements of the plant. The following is a brief list of details on each one:


The Upgraded Option – Air Cooling Systems

Air-powered cooling systems require evaporators to take away the heat from the injection system. After that, air-cooling condensers are used to disperse the heat from the evaporator. The air cooling system works as an intake air fan that directs fresh air to the mold. It also has an exhaust fan to drive away hot air from the mold. Most air cooling systems usually transfer the heat from a running waterline on an injection molding machine to the air surrounding said lines with a cooler. This cooled air consumes over 10% more electricity because air doesn’t conduct heat the way water does.

If you choose to work with an air-powered cooler system, you will be discharging warm air on your plant. The best way to avoid this is to place an air-cooled chiller right outside of the building, preferably in an area that doesn’t have an air conditioner. The increased airflow created by air cooling systems also generates increased amounts of dust, so they also require regular maintenance to keep their high-level performance. Space-wise air cooling chillers can take half the space that any water system needs, but they always should be placed on flat floors.


The Old Fashioned – Water Cooling Systems

These cooling systems are also named “Thermolators,” they operate by pumping cold water through a line that goes right outside the mold cavity and through the gates of the mold. The waterlines are closer to the surface of the molded product to secure an even distribution of the water and avoid warping. The water that goes through the cooling lines is usually treated with chemicals to prevent bacterial growth or contamination of the lines.

Water cooler systems also have two types of water flow. They are known as laminar weave and turbulent weave. The terms are a direct reference on the way water travel with each system. Laminar flow is a straight shot of liquid through the line that keeps the water-centered and prevents contact with the inside surface of the line. Turbulent flow works better to cool off finished parts because it covers more surface space when the water touches the heated mold cavity. The main issue with this cooling system is that it leaves condensation outside of the mold. If the temperature of the room is not regulated, this will cause the mold to malfunction.


The Big Question – Which of These Systems is More Cost Efficient?

There is a common misconception about air cooling systems being cheaper as an initial investment. As we have already pointed out, air cooling systems increases the expenses of any manufacturing operation, and to some extent, it demands to modify existing spaces. The fact that it requires maintenance so frequently should offer a hint. On the other hand, water cooling systems don’t run exclusively on water alone. You will need to make additional expenses on chemicals to treat the water with each production cycle. There is also the fact that water-based systems are riskier for the parts. You will require two different systems in place to achieve the same results offered by a single air-powered system.


Based on These facts – Which One is the Best?

This is a hard call because the final decision should be solely based on the circumstances of the plant using the technology. Plastic injection mold projects benefit a lot from water systems because they do a better job at transferring the heat. Air-powered systems are not as reliable, but they are certainly environmentally friendly. We guess that the final answer to this question is all up to you and the financial health of your manufacturing operation.

Related Products

Air cooled chillers

Other Applications

Temperature controllers are needed in any situation requiring a given temperature be kept stable. This can be in a situation where an object is required to be heated, cooled or both and to remain at the target temperature (setpoint), regardless of the changing environment around it. There are two fundamental types of temperature control; open loop and closed loop control. Open loop is the most basic form and applies continuous heating/cooling with no regard for the actual temperature output. It is analogous to the internal heating system in a car. On a cold day, you may need to turn the heat on to full to warm the car to 75°. However, during warmer weather, the same setting would leave the inside of the car much warmer than the desired 75°.

For example, in a temperature control system, a high fixed alarm prevents a heat source from damaging equipment by de-energizing the source if the temperature exceeds some setpoint value. A low fixed alarm, on the other hand, may be set if a low temperature could damage equipment by freezing.

Temperature controllers are measurement devices used for temperature control. Dividing into thermocouple-type and resistor-type, the electronic temperature controllers obtain the temperature change from the sensor and send the measured data to the electronic processor. The output device will then control the temperature variation within a specific range.

Due to the fact that water is environmentally safe, abundant, easy to handle, and provides much better heat transfer than air, it is the most practical and commonly used medium for cooling of industrial processes. However, the effective use of water for cooling applications results in challenges in design and operation. Most components in a cooling water system are constructed from metallic materials, especially heat transfer equipment. These components can suffer failures due to many forms of corrosion, cracking, and other damage mechanisms. Nonmetallic components in the cooling water system may also experience degradation and failure. The varied types of damage are caused by differences in cooling water system design, temperature, flow, water chemistry, alloy composition, and operation.

A temperature controller is an instrument used to control temperature calculating the difference between a setpoint and a measured temperature. The controller takes an input from a temperature sensor and has an output that is connected to a control element such as a heater or fan.

To accurately control process temperature without extensive operator involvement, a temperature control system relies upon a controller, which accepts a temperature sensor such as a thermocouple or RTD as input. It compares the actual temperature to the desired control temperature, or setpoint, and provides an output to a control element. The temperature controller or thermostat is one part of the entire control system, and the whole system should be analyzed in selecting the proper equipment.