In the food and beverage industry, there can be a lot to consider in selecting the right hose for the job.
Gertrude Stein famously wrote “A rose is a rose is a rose is a rose,” but where the food and beverage industry is concerned, a hose is not a hose is not a hose is not a hose.
With such a broad range of applications in the industry – from dairies to distilleries to grain silos – a wide variety of hoses have been developed to answer various requirements.
“Trelleborg has been offering hoses to this industry for more than 25 years, and some of our earliest products are still in the catalog,” says Christine Dhiersat, Product Manager.
Dhiersat is based at the Trelleborg Industrial Solutions facility in Clermont-Ferrand, France, where all the development and production of food and beverage hoses takes place.
“Development begins with the end users,” she says.
“We try to connect their necessary requirements – say, high temperatures or resistance to fats or increased flexibility. Then we start thinking about what rubber solutions could be the best fit.”
Olivier Libes, Marketing & Product Development Manager, says that initially Trelleborg tried to fulfill those requirements through its existing product range.
“But there were special cases, applications that required either flexibility or environmental controls or security,” he says. “So the whole range of hoses has been designed to address such needs. We use the best rubber compound, tube, cover and construction for the application.”
The list of considerations for a hose can be long, even beyond hygiene. For example, fats and oils can cause a rubber compound to deteriorate, reducing the elasticity of a hose.
The hoses must be able to withstand various cleaning processes, including the use of steam and chemicals such as nitric acid. If the hose handles dry material, like grain or sugar, it needs to be abrasion-resistant on the inside while abrasion-resistance on the outside is a requirement for outdoor applications.
Lighter hoses make handling easier for workers and create a safer work environment. High temperatures, of more than 80 degrees Celsius, age hoses faster.
And there are other concerns.
“With dry products, for example sugar or milk powder, there can be an electrical risk, which can cause an explosion,” says Libes.
“Typically these dry goods are moved at high speeds in a dry atmosphere, so a charge develops between the particles, and the electricity accumulates inside the hose. So we developed Trellvac AL EC with special electrical properties – the EC stands for ‘electrical conductivity’. The hose is designed to conduct the electrical charge in the hose to a steel connection and safely into the ground.”
Another, perhaps surprising, consideration in hose design is whether the hose leaves marks on the floor as it is moved about.
“Black hoses, like tires, leave marks,” explains Dhiersat. “Most of the hoses were black at first, but then we introduced blue covers, especially for the dairy industry, where everything must be kept extremely clean.”
But even the blue hoses were not a universal solution. “Wine makers used to use Citerdial, the hose designed for milk and other fluids,” says Dhiersat. “But we learned that spillage of red wine on the floor would cause the covers of the blue hoses to turn very dark. So we developed special hoses for wine that have a red cover and don’t have this problem.”
One of those hoses, Vinitrell, also features a nonstick surface on the cover. Dhiersat explains, “Rubber has good grip. But when you, say, empty a vat to fill another, this requires a lot of handling of the hoses from one end of a cellar to the other. Our customers said that it was difficult to move the hoses around, so we helped find a solution – a nonstick cover.”
Hose handling in the dairy industry, too, has inspired new Trelleborg hoses. “We developed Lactadial to improve on the weight of Citerdial,” says Dhiersat.
A milk collection hose must be unloaded by a worker from a truck and pulled over to, for example, a connecting tank.
“We wanted to find a way to make it lighter but still keep the characteristics that make Citerdial popular,” Dhiersat says.
“So we changed the steel helix to a plastic helix, which reduced the weight but kept the flexibility and the long lifespan. For unloading milk from a truck we offer Alikler D, which again uses a plastic helix.
"A truck that drives over a steel helix flattens the hose, but with plastic ones, the helix breaks. The round shape of a hose gets restored by pressure in the hose.”
Alcohol production presents its own challenges for hoses. For example, in some distillery applications there are occasions when alcohol stays in the hose for a period of time.
“One of the things about alcohol is that it tends to extract things from rubber compounds, so the alcohol may end up having a different taste,” Dhiersat says. “We’ve solved the problem with UPE, a polyethylene film inside the hose that prevents extraction.”
Similarly, Libes explains, Trelleborg is now working to improve the smell of its hoses. “Natural rubber has a very specific smell,” he says. “We use natural rubber because it is softer and more flexible than any synthetic rubber compound. But we are really looking to reduce that inner smell, which is especially important to wine producers.”
Dhiersat adds, “We must meet stringent regulations in sourcing materials for our hoses, since they will be used in food applications. Regulations are getting more and more strict, so we must stay informed, and the choice of materials is becoming more limited.”
Perhaps so, but the array of hoses is nevertheless increasing. “Food applications are a growing market,” Libes says.
Different applications require different hoses. For the dairy industry, where everything must be kept extremely clean, Trelleborg has developed blue covers to prevent the hoses from leaving black marks on the floor. The Vinitrell hose with its red, nonstick, surface is optimised for use in wine making.