ST Recirculating

Recirculating Air Tunnels

Customers use this style shrink tunnel where the application calls for absolute shrink quality, control of the seal edges, speed or aesthetics.


Belco Shrink Tunnels are designed and built to accept a variety of wrapped products of all shapes and sizes. Loosely wrapped products enter into the tunnel and emerge as perfectly finished shrink packages suitable for any retail level outlet or store shelf.


Built on an all welded tubular steel frame, these machines are available in many heat chamber sizes to meet your production output needs. These machines combine production proven components with modern control technology to monitor and regulate the temperature, air flow and time in the tunnel to create repeatable packages all shift long.


Belco uses a Watlow microprocessor based temperature control with fin strip heaters to maintain precise temperatures within the heat chamber. A direct drive 1 HP blower motor produces a forced air flow which can then be adjusted and directed to the top, bottom and sides of the package as it passes through the tunnel. This forced air flow can also be patterned to contact the film wherever you select to quickly balloon the film about the product and then tightly shrink it down around the contours of the package. This produces consistent, high quality, uniformly shrink wrapped packages, even for the most difficult shapes and sizes.


By having the capability of tuning the airflow pattern around your product, Belco shrink  tunnels can operate at lower, more energy efficient temperatures, run at faster production rates and make less demands on your work space.


For packaging speeds of 200,000 to 4 million packages per year, these Recirculating Air Style shrink tunnels are perfect complements for semi-automatic sealer, automatic L-Sealer and automatic Side Sealer production lines.

Available Models

ST1608    ST1608SS    ST1608L    ST1608LSS    ST1612    ST2210    ST2210SS    ST2214    ST3212    ST3216    ST4410

Standard Features:

- Watlow microprocessor based digital temperature control

- Heavy duty 1 HP blower motor with air flow controls

- Variable speed conveyor control

- Independent Heater On/Off switch

- Direct drive conveyor motor

- Fused electrical protection

- Automatic tunnel cool down and shut-off

- Heavy duty locking casters and leveling pads

Optional Features:

- Multiple Conveyor choices

- Lighted Viewing Window

- Smart Tunnel Control System

- Infeed and Exit Conveyor extensions

- Stainless Steel Construction

- 240/480 Volt 3 Phase Power

ST1608 PLC studio.jpg
Download the 2019 Belco Industrial Brochure

Configurations & Options


Main Power Switch

Turns on/off the power to the entire machine. Maintains all previously set tunnel adjustments, which ensures rapid start up and consistent quality at the beginning of your next shift.

Heater Switch

This switch allows the heaters to be shut off at the end of your production run without having to change temperature settings. This expedites start up and assures quality control. In addition, it facilitates machine “cool down" by allowing the tunnel fans and conveyor to run before you turn off the power switch. This extends machine component life and minimizes down time.

Variable Speed Conveyor Control

Allows you to adjust the conveyor speed to obtain the best quality “shrink" for your products regardless of their size or shape. To further enhance your productivity, you can adjust the tunnel speed to match your production line speeds and prevent shingling or separation of product in multi-pack situations.

Digital Temperature Control

Insures consistent and uniform shrink quality by virtually eliminating any temperature fluctuation within the shrink tunnel. Presents a dual display read-out of both actual and set-point temperature to provide an accurate visual indication of tunnel temperature conditions. An added benefit of digital control is it minimizes setup and changeover time to further increase productivity.

Welded Frame

Belco Shrink Tunnels are built to last. You can depend on years of trouble free production. All Belco Shrink Tunnels start with the same premise… a heavy wall tubular steel welded frame. Solid... nothing to loosen up… nothing to become misaligned and cause unnecessary wear and downtime.

Heavy Duty Locking Casters and Leveling Pads

Belco Shrink Tunnels are mobile. You’ll find them easy to move from one production location to another for maximum production flexibility and productivity. Once in place, the machine leveling pads can be adjusted to match your tunnel conveyor height to the rest of your production line.

Heavy Duty Motor Drive

Built to last. The heavy duty, variable speed gear motor will provide years of trouble free operation.

Tunnel Curtains

Double silicone rubber re-inforced curtains are slit to allow your packages into and out of the heat chamber. This minimizes heat loss and maintains tunnel temperature accuracy and consistency for quality shrink packages.

Assurance Guarantee

All Belco products are built to exacting standards with the finest materials. They are built to be rugged, durable and precise. You will achieve years of productive and profitable service from them.

1hp Blower Motor

Belco Recirculating Air tunnels use a 1 HP direct drive blower motor with a specially designed blower wheel to create the proper combination of CFM and Static Pressure within the tunnel chamber to shrink the film, not burn through it.

Automatic Tunnel Cooldown

At the end of the shift, simply turn off the tunnel Heater switch and then the tunnel Conveyor switch. The machine will begin the cool down cycle and automatically shut-off once a safe cool down temperature of 150°F is reached. A safety disconnect is included for manual shut down override.

Air Flow Controls

Adjustable air flow louvers allow you to regulate the air intake to the blower motor and increase or decrease the CFM of air directed to your package.

Patterned Air Flow Tunnel Design

Unlike competitive tunnels, Belco begins the shrink process as soon as the package enters the heat chamber. Directed air flow to the top, sides and bottom of your package for the entire length of the heat chamber is controlled through a pattern of ½” diameter holes which can be partially blocked, plugged or left wide open depending on your package requirements.

Fin Strip Heaters

These robust industrial grade fin strip heaters provide consistent heat production with no maintenance required.


E-stops Located on Tunnel Entrance and Exit

An emergency stop switch is mounted on the infeed and exit side of the tunnel control box to shut off the machine operation in an emergency situation.

Tunnel Guide Rails (fixed)

Non-adjustable, these tunnel conveyor side guide rails ensure that whatever enters the heat tunnel will exit consistently. Recommended for round or heat sensitive packages.

Teflon Curtains for Use with Shrink Poly

When Polyethylene shrink films enter or exit the tunnel, there is the possibility for hot tacking. This condition tears the plastic off the product resulting in rewraps, as well as down time due to production line contamination of the tunnel curtains. Teflon curtains minimize this problem while efficiently maintaining heat inside the shrink tunnel.

Empty Bag Blow-Off Motor with Switch

An air stream is created across the tunnel infeed to prevent empty shrink bags from entering the tunnel chamber. Recommended for all automatic sealer applications.

Tunnel Infeed or Exit Extensions

The machine conveyor frame can be extended leading into and/or out of the tunnel chamber to fit your production line needs, create a work space for your operators or eliminate the need for an additional conveyor.

Stainless Steel Tunnel Guide Rails (fixed)

Stainless Steel construction is available for food applications. Non-adjustable, these tunnel conveyor side guide rails ensure that whatever enters the heat tunnel will exit consistently. Recommended for round or heat sensitive packages.

220 Volt 3 Phase

Belco can design machinery to meet customers’ power requirements. All machines are tested at their rated operating specifications before shipping to ensure a successful start-up.

440 Volt / 480 Volt 3 Phase

Requires a design change in heating elements, transformers, electrical switches and some other components. Special voltage requests are welcome. All machines are tested at their rated operating specifications before shipping to ensure a successful start-up.

Sealer/Tunnel Adjustable Spacer Set

This option ties together a Belco ILS and an ST to minimize the risk of one machine moving into or away from the other.

Tunnel Conveyor Cooling Fan

This fan system mounts to the undercarriage of the tunnel conveyor and helps cool the conveyor from building up heat which may affect the bottom shrink for some packages and films.

Product Cooling Fan

An overhead fan helps facilitate the shrink process for Polyethylene films by immediately directing room temperature air over the package after it exits the shrink tunnel. Also helps with the handling of hot packages.

Power Cables

For voltages other than 120 Volts, Belco machines ship without power cables and plugs. We can provide the proper power cable for the amp rating of the machine but strongly recommend following the advice of a licensed electrician for proper hook up.

Lighted Viewing Window with Lexan Shield

An unbreakable Lexan shield is mounted to the tunnel to protect the tempered glass window from inadvertent contact with operators, machinery or product.

Digital Conveyor Speed Control

This conveyor speed control provides a digital display which can be set up to read in various units of measure: feet/minute, inches/minute or even time in the tunnel chamber.

*Requires a special motor with encoder feedback capabilities.

Jam Detect Sensor

A photo-eye is mounted at the exit end of the tunnel chamber. When blocked for a determined time period, an annunciator light bar will light up to signal to the operator that product is potentially backing up into the heat chamber.

A signal can also be provided to prevent more product from entering the tunnel until the jam is cleared.

Annunciator/Alarm Light Display

A multi-colored light bar mounted on the top of the tunnel control box signals the machine condition at all times: Green signals the tunnel is ready for operation, Amber signals the tunnel is warming up, Red signals the tunnel is out of temperature or an alarm has been triggered and special attention is required.

Temperature Verification Test Port

A pair of leads from the tunnel temperature monitoring thermocouple go to the temperature control and also to this port for easy access with a calibrated meter. A milli-volt signal verifies the reading on the temperature control is within your operating specifications.

Popular Optional Configurations

Teflon Mesh Conveyor Belt

This durable, non-stick belt is ideal for very small or light weight packages and multi-packs. The design of the mesh belt allows even air flow to all surfaces of your package and is essential when your product must be transported smoothly through the tunnel. Standard mesh opening is ¼” square mesh and for polyethylene applications, use the 1/16” square mesh when needed.

Falcon Belt

This glass filled nylon, open style heavy duty rated belt is excellent for conveying very heavy products, shrinking polyethylene wrapped products or when the minimum maintenance possible is required.

Rod Conveyor

3/8” diameter silicone rubber covered steel rollers transport your product through the heat chamber. As the rollers turn, your product continually moves over the rollers so there is never any imprint or mark on the bottom of your package.

Standard roller spacing is on 1-1/2” centers and Hi-density roller spacing is on 1” centers.

Lighted Viewing Window

This window is active and directs airflow through the inner panel to the product. A tempered glass window on the operator’s side of the tunnel chamber allows for faster set up and easy adjustment of controls to enhance packaging quality and productivity. Because you can observe the conditions required for a proper shrink, you can quickly adjust the temperature, conveyor speed, air flow and even air evacuation. This option has proven invaluable for customers who shrink wrap a variety of package sizes and shapes.

Custom Color

Belco can custom powder coat paint your machine to match your company colors or production floor requirements. Just supply your RAL paint specification along with your request for machine quote.

Stainless Steel Construction

The Belco line-up of equipment is also offered in stainless steel construction for use in Pharmaceutical, Food, Meat, Fish and Poultry processing environments. They comply with FDA and USDA requirements for packaging your product. These are wipe-down rated machines and not designed for washdown cleaning.

Smart Tunnel Control System

This PLC machine control system is available for the entire line of recirculating air tunnels. Featuring a color touch screen, the operator interface controls temperature, conveyor speed and air velocity within the heat chamber. The system can save the setup parameters in its memory for up to 100 products for recall later. These product recipes allow for fast and repeatable product setups.

How to Choose

Which Belco ST is right for you?

Belco manufactures two styles of shrink tunnels to complement every level of shrink film sealer available within our industry. In fact, we are often used as an OEM partner with automatic sealer companies to complete their packaging lines for customers.

Belco tunnels will shrink all commercially available shrink films, including polyethylene, at line speeds from 5 to 150 packages per minute depending on the tunnel chosen.

For manual, semi-automatic and low speed automatic production lines, Belco offers our Fan Style Shrink Tunnels in a variety of sizes. These are often called Convection Ovens.

These Fan Style tunnels use Cal-Rod heating elements, variable speed fan motors and a Watlow digital temperature control to continuously monitor and regulate tunnel temperature. A combination of heaters and fans, positioned above and below the conveyor, moves hot air around your package as it travels through the tunnel chamber, quietly ballooning the film and then tightly shrinking to the contours of your package.

These models are rated for speeds of 5-25 packages per minute or 500,000 to 2,600,000 packages per year, single shift operation.

When the application calls for absolute shrink quality, seal control, speed or aesthetics, Belco manufactures our industry leading Recirculating Air Shrink Tunnel. These tunnels utilize Watlow micro-processor based digital temperature controls and multiple fin-strip heating elements in combination with a forced air flow design to properly deliver hot air directly to the film as your product is conveyed through the shrink chamber. You have the ability to precisely pattern the airflow to the top, sides and bottom of your package which results in the best possible shrink, even for difficult shapes.

These models are rated for speeds of 20-150 packages per minute or 2,000,000 to over 15,000,000 packages per year, single shift operation.


The first consideration is the size range of packages you need to shrink. If the package won’t comfortably fit into the tunnel opening, you can’t shrink it.

Belco tunnels are designed to balloon the film and gently shrink it around your package. This means that for lower profile packages, allow 2-3 inches of clearance between your package and the tunnel side walls. For taller packages, allow 4-6 inches or more if the package is very long. Since the ballooning is most pronounced on the top surface of the package, allow at least 4 inches clearance to pass through the tunnel, more if the package is long or the film being shrunk is Polyethylene.


Do your packages include irregularly shaped designs, windows or high profile cube boxes or cartons? Does the placement of the seal need to be underneath the face of the package for retail appeal? If so, some of your packages may require more precise and consistent air flow control to maintain the quality shrink effect you are after. Consider the Belco Recirculating Air Shrink Tunnels for these applications.


Do you require low, medium or high speed productivity without the worry of rewraps due to poor shrink quality? Consider how many packages you need to produce to meet peak demands as well as satisfy your regular production schedules. Belco has tunnel chamber lengths from two feet to eight feet long which are designed to meet your specific packaging speed requirements.


Belco tunnels can be built to include a range of standard and custom options depending on the needs of the finished package. First, choose the proper conveyor type, maybe add the Lighted Viewing Window and then determine which tunnel length will fulfill your packaging output requirements. Then, review the other options such as power based on your existing facility utilities. Belco staff will be happy to help explain other options that will complete your machine build.


Belco tunnels are designed to run multiple shifts with little to no maintenance. The controls and heaters are all rated for industrial use and require no maintenance. The bearings, motors and conveyor components should be checked periodically for alignment and performance. The tunnel curtains are designed to keep heat inside the tunnel chamber and loose film or empty bags out. Regular housekeeping and a PM schedule should allow for years of productive use and performance.

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