Choosing the right hoses for transporting gases and fluids is critical for raising uptime, cost-effectiveness, and safety. In contrast, using the wrong hoses could lead to severe downtimes, higher risks, and lower profits. With the high stakes involved, what should maintenance technicians, plant managers, and design engineers consider when choosing and specifying hoses for their machines and equipment? Hose life, maintenance requirements, replacement costs, and other ownership costs are some key factors influencing the final decision. To arrive at the best decision, it is crucial to thoroughly understand the available options for hose materials, construction types, end connections, and the intended application; each makes a big difference in the hose’s performance.
Each hose has several key components: the core, end connections, and reinforcements or coverings. Below, we go over each of these components’ functions and how they help increase system performance and improve safety.
Since the hose core handles most of the work, choosing a suitable material for the application you have in mind is essential. To do this, one must first ensure compatibility with the transported medium, like fluid or gas, as well as factor in permeation and chemical compatibility. Apart from being able to contain the fluids securely, the core should also be resistant to the fluid’s degradation without affecting or changing its properties. The core should ideally be capable of handling process parameters like pressure and temperature, including anticipated stresses resulting from their rapid changes. The most common core materials available are metal, Teflon/silicone, and rubber.
Metal is an excellent choice for various fluid subsystems. Its wide temperature range makes it the best choice for handling fluids running at high temperatures. 316L stainless steel is a popular choice, usually rated for temperatures between -198°C to 454°C and is used for hoses, pipes, and stainless steel pipe fittings in Singapore. Metal tubings with extra flexibility are also highly reliable for low absorption or permeation requirements. However, they are a less than ideal choice when it comes to moving acidic or highly caustic fluids that cause corrosion. Furthermore, they could potentially fail when subjected to constant vibrations or repetitive movements.
Silicone cores perform exceptionally in situations where cleanliness is paramount, such as in food and beverage industries and pharmaceutical environments, due to their innate flexibility and compatibility with sanitary requirements. They can generally withstand temperatures between –54°C to 315°C – anything higher could turn the silicone brittle and cause them to break down.
However, silicone has its drawbacks, such as its absorbent nature. This could result in hose contamination if fluids somehow get absorbed into the core’s walls. The fluid could remain stuck and stagnant before seeping back into the stream and contaminating the flow.
Although it was mentioned that it could handle a slew of sanitary requirements, that does not automatically mean it is easy to clean. With its limited chemical compatibility with the most common detergents and solvents, silicone can prove challenging to sanitise thoroughly. Steam cleaning may also prove ineffective at completely removing any absorbed fluids in the core.
Rubber is one of the economical choices for hose cores yet retains high versatility and durability, allowing it to be crushed without experiencing permanent damage. Additionally, rubber core hoses can be made with little to no special tools and equipment. Their temperature tolerance ranges from -40°C to 93°C and is available in diameters greater than 2 inches.
The biggest drawback of rubber hoses is that they are limited to applications with less than 34 bar or 500 PSIG. Lastly, rubber also tends to erode more quickly than other options.
End connections enable hoses to be safely and securely attached to fluid-handling devices. The materials used for this component are usually determined by the materials used for the hose. For instance, its connectors will have permanent seals since metal hoses are welded. Other nonmetallic hoses, in comparison, will be crimped or swaged. These two methods are generally accepted, but the former (which presses on the end connection instead of the hose) is far less likely to damage the hose since the pressure is applied more carefully. Moreover, end connections must not introduce torsion to the hose during installation as it may result in premature failure.
Beyond materials, there is a large variety of connection types that cannot be fully covered in this article. As such, the best option would be to simply choose the connectors made for specific uses, such as:
- General industrial markets
For most industrial use cases, the main requirement for end connectors is to perform well even under high pressures that could reach up to 60,000 PSIG. End connections need to meet or exceed the pressure rating of the hose and attach in a way that, in case of failure, the hose gets compromised instead of getting separated completely.
- Pharmaceutical and biotechnology
In these industries, cleanliness and sanitation take top priority for end connectors. Thus, cleaning and maintaining them should be relatively easy, whether taken apart or subjected to a clean-in-place process. Lastly, their materials should innately mitigate bacteria growth and resist corrosion.
Material purity is generally the highest priority when it comes to semiconductor production. End connectors here should therefore be of high purity, ideal for sensitive environments, come with fine threads, and be designed and covered with contaminant-resistant materials.
Reinforcement and coverings
In certain cases, hose reinforcements and coverings are necessary depending on the application’s flexibility, pressure containment, and safety requirements. Here are a few things to consider:
- Reinforcement layers, which usually take the form of a woven and flexible stainless steel braid, are often used to surround the hose core. These layers help improve the hose’s flexibility and pressure containment. All hoses have their specific minimum bend radius that measures how far they can bend before kinking.
- Covers are the hose’s outermost layer that protects the layers beneath and the personnel working or interacting with the surrounding equipment. They are part of the hose and are made of various materials, with silicone being the most common for general-purpose hoses.
- Silicone covers prevent fraying in stainless steel reinforcement braids, which can occur due to abrasion. If braids get frayed, they could compromise the hose’s integrity and result in a burst threat that may lead to injuries. These covers also provide increased burn protection for workers that inadvertently bump or grab hoses moving high-temperature fluids. Moreover, they provide additional insulation to maintain fluid temperatures or remove bacteria buildup in crevices.
There are numerous and different variables influencing hose selection. Thus, it is imperative that design engineers stay updated on the available options as well as the requirements of their fluid-carrying applications to make the best, informed choices.
Should you require metal, silicone, or rubber hoses for your business applications, Pharmchem Engineering has got you covered. With a mission to provide industrial engineering supplies paired with a decade of expertise, we are equipped with a variety of sophisticated solutions to meet the global business demands across all industrial fields. Whether it be pipe pigging equipment, vibration mounts, or fabric expansion joints, contact us today for a solution catered to your requirements and objectives.