10 Considerations for Premelter Design
When designed correctly, a premelter reduces product waste and enhances product appearance.
An infrared premelter emits a flash of heat (infrared energy) to the top of food products to gently fuse ingredients together. This process reduces product waste during packaging and distribution processes. It also enhances product appearance and presentation.
To reap the most reward from this type of equipment, consider the following tips when specifying a design for your custom premelter.
1. Select a Fuel Source
Choosing a fuel source is one of the more important decisions to be made when selecting a premelter. This decision usually is determined by fuel cost and availability. Infrared (IR) heat can be generated from natural gas or electricity. Each option has advantages and disadvantages (table 1).
Both types of fuel have a reasonable range of heat output to adjust for varying product conditions. While there are many reasons to choose one fuel source over another, this decision will depend on the particular process, cost and availability of the fuel resources.
2. Understand Product Characteristics and Optimize Equipment Versatility
A variety of food production processes can benefit from the use of a premelter. For instance, frozen pizza manufacturers use premelters to gently fuse the cheese and additional toppings before entering a blast freezer. This premelting process prevents the ingredients — either fresh or frozen — from falling off during processing or becoming loose after packaging, during shipment or when vertically displayed for resale.
Any food product that requires a melt or flash of heat can benefit from a premelter. Frozen cheese bread, quesadillas, prepared meals and other food items are some of the products that regularly are run through a premelting process.
3. Calculate Residence Time
Many elements affect residence time, or how long the product needs to travel under the heat source. The manufacturer will first determine the customer’s range of line speeds. Speeds may fluctuate depending on product recipe variations such as size, thickness or ingredients for a given production run.
Conveyor speeds and heat requirements necessary to provide an even melt are critical factors in determining the optimal treatment length. Using multiple heating elements allows more adaptability for varying product types while maintaining the proper melting time. The heat source must be close enough to be effective but not so close that it overheats the product. A premelter with components that can be adjusted to specific requirements will ultimately generate a more consistent result.
4. Consider Conveyor Belt Selection
Selecting the correct conveyor belt for the process involves considering the range of materials that can be used, including metallic wire, wire rope, lamella, plastic and hybrids. An open metallic or wire-type belt is the most common style used in premelters.
The conveyor belt selected affects the transfer of heat to the product. The area covered by the product itself affects the surface temperature of the conveyor belt. If a consistent temperature is needed on the bottom side of the treated product —though this is uncommon — this needs to be taken into account.
5. Figure Out Floor Spacing Requirements
The overall footprint of the premelter needs to be factored in relatively early in the design process. After determining the line speed, residence time and conveyor width, the overall footprint of the premelter can be calculated. Because a premelter often is an addition to a current production line, the required space and implementation options must be considered carefully.
6. Select Sanitary Design
An experienced food machinery manufacturer will follow good manufacturing practices concerning food-safety hygiene requirements in the design of its equipment. Generally, equipment must be easy to clean, made of approved materials that are suitable for the operating environment, and compatible with the user’s cleaning process and sanitizing procedures.
For a premelter, access is greatly enhanced when the conveyor and heat source areas can be separated easily during the cleaning process. Options include a removable docking conveyor with a cantilevered heating section, a hinged heating section to ease access, or a heating section that automatically retracts above the conveyor. An integral belt-washing station or other clean-in-place (CIP) techniques can be incorporated according to the user’s preferences.
7. Factor In Controls
If the premelter does not need to be networked to other pieces of equipment, a simple approach may be the best solution. The control approach can be as straightforward as a series of relays and pushbuttons. This technique would be the most cost effective and potentially the most robust for high ambient room temperature conditions. The troubleshooting would involve just a voltmeter and a set of schematic drawings.
By contrast, if the process requires the premelter to relay information about production, a PLC may be necessary to gain remote connectivity. This would provide the ability to store recipes or to gather production statistics. A PLC also enables any changes or fine-tuning to be done while the premelter is in use, preventing downtime. Suitably chosen and applied controls can be maintained easily by support staff.
8. Plan for Safety
The manufacturer should follow good manufacturing practices and guidelines such as OSHA standards for machine guarding to provide for safe operation and the safety of all users of the equipment.
When inherent hazards such as rotating or moving parts, pinch points, wrap/entanglement points and hot areas cannot be designed out of the equipment, they should be minimized and then safely guarded in a sanitary manner. Additional safety measures may include emergency stop buttons, stop bars or pull cords as well as visual warning and marking systems.
For the design of electrical power and gas combustion systems, the manufacturer will closely adhere to regulatory agency design standards and guidelines. Process-monitoring devices are included to ensure safe operation of the equipment. Visual warning beacons and audible horns may be incorporated into a relay or PLC-based process control system, and a PLC-based system may display highly specific alarm information for successful troubleshooting.
9. Think About Installation
When purchasing any type of equipment, having an installation plan and communicating these considerations to the manufacturer early on is a key factor in a successful design. Determining all available entry points and measuring the sizes of doors, loading docks and hallways can ensure that any size limitations are factored into the premelter design. Work performed in advance will reduce any downtime required for installation.
Also, choose a supplier that is willing to work around production scheduling. A supplier’s past experience with the food production environment will make installation more efficient. With proper planning and mindful design, installation of a new premelter will be swift and successful.
10. Manage Maintenance
As with most production equipment, preventive and scheduled maintenance will be necessary for the longevity of the machinery. Typically, maintenance is required due to contact of the processed material with the heating elements. Preventive steps can be taken during the design process to reduce the amount of contact that the product makes with the heat source, which will require less downtime during maintenance.