If maintaining product temperature is essential during transport, filling and other packaging operations, consider flexible heated transfer hoses.

Heated transfer hoses incorporate an RTD to sense product temperature. The built-in sensor, coupled with a controller, maintains the product temperature within tight tolerances.

Heated transfer hoses are fully encapsulated fluid transfer systems that provide uniform heating throughout the hose. These hoses keep fluid at an elevated temperature and can actually improve the properties of the liquid or gas in many applications.

Heated transfer hoses are rugged, durable and flexible alternatives to wrapping rigid pipe with heat trace or heating tape. The construction is lightweight, operating temperatures are adjustable, and the hose is prewired to ease installation. For safety, all metal hose parts are fully grounded.

Most heated hoses are constructed of tubing (usually manufactured from Teflon) that is reinforced with stainless steel braiding. A sensor mounted directly on the braiding signals an external temperature controller. Silicone-encapsulated heater wire applied to the braiding's exterior achieves the wattage density required by the application. Thermal insulation wrapped on top of the heater wire ensures worker safety and provides a warm-to-the-touch hose exterior.

Applications for heated transfer hoses are quite diverse - they can be used to transfer any nonexplosive liquid or gas. A look at seven ways heated transfer hoses are used may show you how they could work in your application.

Making Wax and Gel Candles. A.I. Root Co., Medina, OH, manufactures traditional wax candles as well as many of the newer gel-type candle products. Material transfer of both wax and gel at application temperatures present a number of challenges. Wax and gel cannot overheat or the candles will be substandard.

"Using heated transfer hoses works well for us - with our application, temperature is critical," said Greg Veigl, manufacturing engineer for A.I. Root. "If wax is too cold, it won't flow through the line via gravity feed. If it is too hot, it will melt the plastic container we are putting it in."

An additional challenge is the potential for changes in material properties if the temperature is off-spec. With the gel products, if the temperature exceeds 260°F (127°C), a hazy cloud forms in the middle of what is supposed to be a clear gel candle. If the wax products get too hot, the material loses its most expensive component - its fragrance. It also takes longer to cool, so the production rate drops.

"The heated hoses keep our process contained," Veigl noted. "If we didn't have the hoses, we'd have large open hoppers of heated wax or gel, which pose a safety hazard for our workers.

A heated hose is constructed of Teflon tubing reinforced with stainless steel braiding. Silicon-encapsulated heater wire and thermal insulation complete the basic package, but custom options can be added.

"With the hoses, the hazard is nonexistent. The temperature of the hose exterior is safe, and the hoses are easy to relocate around the plant for different jobs," he concluded.

Because the heated hoses have worked so effectively for the traditional wax and gel-type candles, Veigl is investigating the use of heated transfer hoses in the pillar candle section of the plant.

Manufacturing Roofing Shingles. Among many other products, Owens Corning, Irving, TX, manufactures roofing shingles. One of the last steps in making this product is using heated transfer hoses to extrude an asphalt-based sealant onto the back side of the shingles. Once the shingles are installed on a house, the sealant melts due to the sun's heat and provides a watertight bond between each shingle.

Durability is a key feature that Owens Corning demands from its heated transfer hoses. Tommy Hulsey, maintenance buyer at Owens Corning, finds that the hoses are "much more reliable than the previous means of material transfer we used. The hoses, coupled with our extruding system, can accurately control the amount of sealant applied onto each shingle. Consequently, we are not wasting material like we once did.

"With this application, we only have one pass to get this right - our line speed is 630 ft/min," Hulsey noted. "A rework station is not an option for applying the sealant." With the heated transfer hoses, Owens Corning can be sure that the adhesive is applied at the right temperature on each shingle.

Gas Delivery. Heated transfer hoses also can be used to maintain the temperature of gases. Toronto-based Hydrogenics Corp. uses the hoses in a precise gas delivery application. Correct flow rates are an important part of this process, so the company orders several different core-sized hoses.

"We just started using heat transfer hoses last June, but our volumes are going up," said Joe Cargnelli, vice president of engineering at Hydrogenics. "Although they are a fairly new piece of equipment for us, we like using the heated transfer hoses. We are now ready to start specifying hoses for a prototype machine we are working on. This will include hoses with 1.5 to 2" inner diameters because we will need higher flow rates."

Employing a discrete temperature controller on each heated hose assembly allows processors to control each hose's temperature independently.

Liquid Dispensing Systems. Equipment Express, Laporte, IN, manufactures a variety of liquid dispensing systems. A typical system includes a fill bin with several outlets on the bottom. Hoses are installed at each outlet via a fitting adapter, and each hose is routed to a fill head.

"We found out about heated transfer hoses through web research," explained Jeff Ake, president and CEO of Equipment Express. "They suit our application - putting the hoses on our liquid dispensing systems - quite well. The hoses are modular, and I really like that they are each a complete, encapsulated unit that can be easily incorporated onto our equipment."

Equipment Express uses the heated hoses to maintain product temperature while transporting molten products such as petroleum jelly, lip balms and body gels.

"Our filler bins are enclosed in what we call hot boxes, and the hoses are used to transport the material at temperature to the dispensing points. The hot box system really wouldn't be possible without heated transfer hoses. Most importantly, the hoses allow us to hold a specific temperature in the product pathway. This is critical to the process."

Equipment Express's ability to hold the product at temperature is attracting attention from customers. "We are seeing a great deal of interest in our new heated systems. And, we are even incorporating the hoses onto our existing, nonheated equipment as an upgrade feature. The performance of existing products improves significantly when we integrate the heated hoses."

Using the heated transfer hoses, Ake's staff has found that it can handle many molten fill products that it otherwise would not be able to. "Simply put, the hoses allow us to address some interesting applications and attract new business," Ake concluded.

Cosmetic Fluid Transfer. New World Cosmetic Packaging Co., Carteret, NJ, is a contract packager specializing in cosmetic products. The company is an original equipment manufacturer for certain chain department stores and for leading cosmetic companies. It routinely processes and packages base makeup, mascara, body gel, body lotion, lip liner and lip gloss as well as other products.

"We use heated hoses to transfer certain cosmetic materials," said John Lucev, director of engineering for New World. "Heated hoses are simply a necessity, especially when the transfer is over a significant distance. The hoses perform well, maintaining the temperature of critical fills within a tight tolerance range.

"Our most difficult application is putting three different materials, one on top of another, in a clear container. Each material is a different color for marketing appeal. We are dealing with not only three different materials, but also three different temperatures and delivery from three different kettles," Lucev noted.

"The hoses are ideal for material transfer, especially from the kettle to the fill head. Without the heated hoses, there would be a lot of applications we simply couldn't do. After all, we are filling 0.5 oz, 2 oz and 5 gm bottles with line speeds of 60 bottles/min." Despite the brisk line speed, the heated hoses on New World's packaging lines have proved durable. Lucev reported that no hose failures have occurred despite the sometimes rough handling they experience.

Boiler Feed Water and Loading Station Material Transfer. The Instrumentation Division of Control Equipment Co., Marietta, GA, supports heat trace applications for end users in Georgia as well as most of Alabama, Florida and Tennessee. The company integrates heated transfer hoses with heat trace as well as self-standing flexible hose applications.

"I like the heated transfer hoses because of their durability and flexibility," said Cliff Fleming, instrumentation divison manager at Control Equipment. "I can even take a modular approach and add more length as I need to. With my application, I am transferring a cement-based product that solidifies at cooler temperatures. Solidification as well as downtime is simply intolerable.

"When I have an application that accommodates heat trace, I still might need a flexible heated hose for the last 20' or so of my material transfer," Fleming noted. "This includes boiler feed water transfer and fluid transfer at loading stations. The flexible hose completes the job and gives me a complete fluid transfer package."

Fleming finds heated transfers hoses complement heat tracing. "Conventional heat trace methods are simply impractical for some applications. Where flexibility is required, a rigid tube will fatigue and break. In that sense, there is nothing comparable to the flexible heated transfer hose. And the adjustable temperature controller concept is a huge plus."

The versatility of heated transfer hoses provides application flexibility, both in the planning stages of a new process and in day-to-day use.

How to Promote Long Hose Life

You've invested both time and money to select a heated transfer hose. To ensure long hose life and get the most from your investment, follow these operating tips:

  • Suspend hoses using hose hammocks or hose straps whenever possible.

  • Avoid the use of tie wraps or tape on the hose exterior.

  • Train workers to avoid stepping on hoses.

  • Flush hose interior with the manufacturer's recommended solvent whenever changing from one fluid to another.

  • Prevent the hose exterior surfaces from touching another hose or touching its own exterior. Maintain a 1" clearance between any adjacent hose surfaces.

  • Do not exceed the recommended hose minimum bend radius.