Throughout a food and beverage plant, you have three different zones, Basic Hygiene, Medium Hygiene, and High Hygiene with their unique hygiene concerns. Additionally, steel and temperature requirements can vary significantly. Failure to understand your application needs can result in equipment failure, flash condensation, and other potential hazards.
Understanding temperature requirements
Most people believe it’s best to keep the internal enclosure temperature at a low level. However, controls operate best when kept between 90-104 degrees. If the internal temperature drops too low, you are wasting energy, opening the door for condensation, and risking equipment failure.
Just as enclosures can lock in heat damaging controls and internal components, having internal temperatures that are too cold can have a negative impact. If your internal temperature drops too far below your ambient temperature, you are increasing the likelihood of condensation forming inside the enclosure. You have three options to prevent this.
1. You can add an internal fan to your enclosure. The moving air will help eliminate condensation.
2. You can install a condensate drain. This is a one-way valve that will allow water to escape but does not permit it to enter.
3. You can use a heater to increase the internal temperature when enclosures are being used in cold environments and in the High Hygiene Zone where high temperature wash downs are likely to occur.
Proper temperature management is essential to keeping your electronic equipment and controls functioning at optimal levels and by default your plant operations. Essentially you want to understand your temperature needs and keep the enclosure at a correct and consistent level throughout all operations. This includes cooling the unit as needed, but also heating if internal temperatures fall too low or during certain cleaning processes.
Prevent overheating and condensation
To prevent the electronics and electronic controls from overheating, first you need to understand the best internal temperature. To keep your controls functioning and prevent internal condensation, keeping the internal enclosure setting between 85-95 degrees Fahrenheit is standard. Second, you want to understand the average ambient temperature on your plant floor and determine if there are fluctuations or a relatively consistent level.
Once you have the internal temperature needs and the ambient temperature, you can calculate your cooling needs; Rittal’s Therm 6.7 Software can assist in calculating your unique cooling requirements. Once you determine your temperature setting in the Basic Hygiene and Medium Hygiene Zones, few adjustments will need to be made. However, in the High Hygiene Zone, you may need to adjust the temperature during wash down procedures.
When conducting a wash down of your enclosures in the High Hygiene Zone, use of extremely high temperatures is expected. Water and chemicals can reach over 170 degrees and hit the external of enclosures that have an internal temperature of approximately 90 degrees. This extreme temperature differential can result in flash condensation as the hot water makes contact with a cooler surface.
To prevent flash condensation from forming, you want your internal temperature and external or wash down temperature to be equivalent. You should shut down the cooling system prior to beginning the wash down procedure. Next, you should use an internal heater to raise the temperature so that both the water you’ll be using and the enclosure have equivalent temperatures. This helps to diminish the temperature differential and prevents condensation from forming.
A strong understanding of your heating or cooling needs will ensure your plant operations remain running efficiently. You will then be able to have a foundation for selecting the correct equipment for the application.
Cooling systems
There are two types of cooling systems that offer varying degrees of protection, closed loop or open loop. Their applications will depend on the environment and protection level needs.
A closed loop cooling system will prevent ambient air and particles from entering the enclosure. The internal air and external or ambient air remain separated and is the ideal solution for maximum protection of components and electrical equipment against dust and moisture.
Within a closed loop system, the sensors allow the climate unit to self-adjust based on the cooling requirements. The cooling systems will pause once the desired temperature is reached and resume when the internal temperatures rise providing a more energy efficient option than the open loop system.
Sensors used in open loop systems may be less accurate compared to those in closed loop systems. They tend to be designed to start and stop the climate system, but not to regulate the internal temperature. In an open loop system ambient and internal air circulate with the use of an exhaust or fan system to push cooler ambient air into the enclosure and pull the hot internal air out. Therefore, cooling is dependent on the difference between the ambient air and internal air.
As this system circulates air, it can pick up dust and other particles. A filter can remove some of these, but some contaminants will enter the system. In a clean environment this is not a primary concern, but when working in an area where the air may have particulates, it can lead to build up inside the enclosure and result in equipment failure.
Understanding your environment and using the correct cooling system for your application will further prevent equipment failure and unplanned downtime.
Material needs
Another key consideration to ensure electronics stay protected is to make certain you are using the right material for the environment and the application. Steel is a great option for most applications and the two most common steel types used throughout the food and beverage plant are T316 and T304.
T316 is a stronger and more corrosive resistant steel. It is best used for harsh environments that are chlorine rich and / or using high corrosive solvents such as those in the High Hygiene Zone. However, T304 is a great choice for plenty of food and beverage applications and will likely be sufficient in the Basic or Medium Hygiene Zones. In environments that are using nitric acids, you are better off using T304 as the nitric acid can cause pitting on the T316. Nitric acids are typically used for fertilizers, pharmaceuticals, fungicides, and explosives.
Once the basics of temperature control, climate systems, and steel type are established you can start to customize your solutions. One main feature of enclosures is to protect the internal components and electronics. However, controls can be installed on the external facing door to operate equipment. When enclosures are used as a control station, you will need to modify them to fit the desired controls and switches while keeping the required application protection.
Modifications
At Rittal, we have three approaches to modifications:
1. Occasionally, products can be modified by hand. This depends on the modifications needed and if the other two options are not viable solutions.
2. Items can be modified through our Ohio factory during the flat or fabrication stage. The holes and modifications are done pre-cleaning. This allows modifications to be made before assembly and before shipping enabling a ready to implement custom solution.
3. Our Perforex Machines provide cut options and laser options to customize your enclosures. They provide a faster, efficient, and consistent way to complete the required modifications. Using the Perforex Machine(s) is a great solution when working with an Integrator or Panel Shop and there is a need for many modifications across multiple enclosures.
Rittal’s standard product can be pulled from stock so that holes and cutouts can be added for your push buttons and control devices that need to be accessible from the outside of the enclosure. There are certain designs that can be built up including screw box covers to large free-standing designs. Our HD line, designed for food and beverage applications, has everything from small boxes and push button boxes to freestanding enclosures.
As your enclosure systems and equipment needs grow, customizing configurations is a great solution. You will be able to design the enclosure system to meet your unique needs and the available space. Rittal has an online configurator tool which allows you to customize the enclosure system to your specifications. Within the tool, you determine the standard ratings you need, the height, width, application type, and can add accessories. You will then be able to pull the specification sheets, product sheets, and place your order from within the configurator.
The process may seem daunting when it comes to understanding the three food and beverage plant zones and the unique applications for each, but Rittal is here to help walk through each challenge. Our knowledgeable teams and our comprehensive tools simplify the process.
To learn more, watch the webinar on Choosing the Right Enclosure.