Hoses are important equipment used in different industries. Their role is to transport liquids, gases, and other materials easily. Different types of hoses are available on the market, differing in their materials. Among those, rubber hoses are widely popular due to their flexibility. However, many people still ask: What are rubber hoses and how are they manufactured?
Rubber hoses are made from high-quality rubber. As a result, these hoses are very flexible and durable, and they do not deteriorate even when kinked. What makes these hoses stand out is their versatility. They can be used for a wide range of purposes and industries. In this article, I will discuss everything about rubber hoses and how they are made. So, let’s get started.
Overview of Rubber Hoses
Before discussing the manufacturing process, I will first explain the basics of rubber hoses.
As the name suggests, rubber hoses are made from different types of rubber. As a result, these hoses are flexible, elastic, and stretchable. Additionally, these hoses remain in good condition even when used harshly and kinked. They consist of three layers – the innermost layer is made durable to withstand liquid, oil and other chemicals.
As I said above, these hoses are made of rubber materials. However, there are two major types of rubbers, which are as follows:
- Natural Rubber
- Synthetic Rubber
Natural rubber hoses are more flexible but less resistant to chemicals and oils. So they are not recommended for transporting harsh chemicals or oils. Conversely, hoses made of synthetic rubber are durable. The best examples of synthetic rubbers include nitrile (NBR), neoprene, SBR, and EPDM.
The NBR hose is suitable for transporting oil. Similarly, the EPDM rubber type is excellent against high temperatures. So those made of EPDM are used to transport steam. People generally prefer hoses made of synthetic rubber for transporting different chemicals. In construction, rubber hoses are made in three layers. These include the inner layer, the reinforced layer (middle), and the outermost layer.
Inner layers are exposed to chemicals or fluids and made to withstand these elements. Reinforced layers generally consist of either fabric reinforcement or steel braiding. This layer is what makes the rubber hose resistant to high pressures. Lastly, the outermost layer is made of synthetic rubber. This makes the hose resist UV rays, high temperatures, and more, and perform excellently.
How are Rubber Hoses Manufactured?
Interestingly, rubber hoses at first sound fragile and only good for light use, right? However, that’s the truth – as these hoses can be used for heavy-duty applications. They can transport oil, chemicals, slurry, beverages, and the list goes on. But how are they made to be so strong despite using rubber materials?
In the section below, I will discuss key steps involved in manufacturing these rubber hoses.
Step 1- Raw Material Compounding & Mixing in Internal Mixer
The manufacturing of rubber hose starts with the selection of raw materials. As I said above, there are different types of rubber that can be used for these hoses. Manufacturers carefully select the rubber types as raw materials. This selection is based on the properties the manufacturer wants. If they want hoses to be more flexible, they may choose natural rubber.
Similarly, manufacturers choose NBR materials when making rubber hoses for oil transportation. Interestingly, some manufacturers also choose different rubber types and mix them. After selecting the rubber type, the next step is to mix the raw materials. For this process, an internal mixer, also known as a Banbury mixer, is used.
In this machine, the raw materials of precise weight are subjected to high pressure and temperature. This ensures that raw materials are evenly mixed and distributed throughout the mixture. So, these materials have equal strength, durability, and flexibility, even though they are made of different types of rubber.
Step 2- Inner Tube Extrusion & Mandrel Insertion
Once the raw materials are ready, the next step is to create an inner tube. Interestingly, the innermost part of the hose is exposed to oil, gas and other fluids. So it must be uniform and have a precise shape. For this inner tube extrusion, manufacturers use dedicated extrusion machines. These machines consist of dies which shape the inner part of these hoses.
The material is fed to the machines, which force it through the die. When the material passes through the die, it forms a hollow, tube-like structure of rubber. This whole tube is actually the inner part of the hoses. As I said, the inner side of the hose must be shaped and dimensioned. If it is not, the fluid, oil or gas may not flow through it consistently.
That’s why manufacturers add a mandrel inside this hollow tube. This mandrel ensures the tube or hollow structure remains firm and does not deform. The mandrel insertion becomes even more important when the margin of error is low. A mandrel is required when you need a rubber hose with a precise inner-tube shape and size.
Step 3- Formation of Reinforcement Layer (braiding or spiralling)
As you know, the reinforced layers in rubber hoses give them the strength to withstand high pressure. For this, the inner rubber tube is passed through a braiding or spiralling machine. This machine is responsible for making reinforced layers. Generally, polyester fabric is used for making these reinforced layers. However, for high-end hoses, steel braiding is also used, which is superior to fabric reinforcements.
In braiding, polyester or steel is wrapped around the inner tube to form a criss-cross pattern. In contrast, spiralling fabric or steel wires make helical patterns. Both spiralling and braiding ensure rubber hoses become strong. As a result, it can easily withstand harsh pressure. The rubber hoses without these reinforcement layers may fail when exposed to high-pressure fluids.
Step 4- Outer Cover (Layer) Extrusion
The outer side of the rubber hoses is exposed to harsh conditions. These include sunlight, UV rays, moisture, and more. Therefore, manufacturers apply a rubber coat or layer (cover) on the reinforcement layer. This outer cover is applied through the extrusion machine. These machines carefully apply rubber coating with uniformity.
Remember, the outer layer is made of rubber with some mixed additives. These additive selections are based on property manufacturers. If the hose is intended for use in moist conditions, it will use additives that provide moisture resistance. That’s what makes rubber hoses resistant to moisture, UV rays and other environmental conditions.
Generally, synthetic rubber is used to make this external layer. Why? That’s because this type of rubber offers better performance than natural rubber. The importance of this outer layer increases even more when the hose is used in heavy-duty applications. These include transporting slurry and chemicals under the harshest conditions.
Step 5- Vulcanization & Cooling
The hose with an outer layer may feel more like plastic. It won’t have flexibility and elasticity, which is a drawback. That’s why manufacturers use vulcanisation for curing. In this process, the rubber hose is placed inside a hot air chamber. This chamber exposes the rubber hose to hot air.
This hot air removes plasticity, making the rubber softer through a reaction. How? The reason is that sulfur is present inside rubber and reacts with hot air. This reaction is responsible for making rubber stronger, more durable and more elastic. After this, the rubber hose is generally left to cool naturally for some time. This cooling gives rubber hoses stability and internal strength.
Once cooling is complete, the rubber hose undergoes inspection. In large companies, there is a dedicated team which inspects the hoses. This ensures each hose made has no defects and fulfils its expected lifespan. If a rubber hose has any defect, it is generally not approved. It is sent back to the manufacturing facility for improvement. The high-quality hoses are approved and sent to market for customers to buy.
Rubber Hoses Types
Interestingly, there is a wide range of rubber hoses available in the market. These hoses differ in their properties and use cases. Interestingly, rubber general-purpose hoses are typically less robust and more affordable. In contrast, those hoses with premium quality and greater strength are expensive but long-lasting. Below is the list of some popular types of rubber hoses:
- Oil & Fuel Rubber Hose
- Air & Water Rubber Hose
- Steam Rubber Hose
- Chemical Rubber Hose
- Hydraulic Rubber Hose
- Food Grade Rubber Hose
Remember, most of these rubber hoses have a simple construction. They have three layers: inner, reinforcement, and outer. For hoses that are exposed to high pressure, reinforced layers are important. In hydraulic hoses, these reinforcement layers typically consist of steel wire braiding. This steel wire makes these hoses withstand harsh pressure and perform excellently.
Applications of Rubber Hoses
As discussed above, rubber hoses are versatile. This means they can be used for a wide range of applications. Interestingly, different types of rubber are used to make these hoses. These versatile materials make the rubber hoses unique and give them distinct properties. The cheaper rubber hoses are good only for water.
On the other hand, there are robust rubber hoses used to transport harsh chemicals, slurries, and so on. Below is the table showing the popular applications of these hoses in different industries:
| Industry | Use of Rubber Hoses |
| Automotive | Fuel lines, coolant transfer |
| Construction | Hydraulic systems in heavy machinery |
| Agriculture | Irrigation, pesticide spraying |
| Oil & Gas | Fuel, oil, and gas transfer under pressure |
| Manufacturing | Air, water, and chemical transfer |
| Mining | Slurry and dust |
Frequently Asked Questions
What is a rubber hose?
Rubber hoses are flexible hollow tubes consisting of three layers. These hoses are used to transport liquids, gases, slurry and so on. Rubber hoses are known for their flexibility, durability and performance in harsh conditions.
What is the difference between silicone and rubber hoses?
Silicone hoses are an ideal option for high-temperature applications. But they are less flexible, and kinking or bending can damage them. On the other hand, rubber hoses are flexible and durable, but may not be ideal for high-temperature conditions.
What materials are used to make rubber hoses?
Both natural and synthetic rubbers are used in making these hoses. However, common materials used include neoprene, SBR, NBR, EPDM, and so on. These materials make the rubber hoses strong and durable without affecting their flexibility.
Conclusion
In short, rubber hoses are of utmost value for modern industries. What makes rubber hoses very special is their versatility. This means customers can choose high-quality rubber hoses to suit their needs. For example, cheaper and simpler rubber hoses are good enough for watering the garden. On the other hand, strong rubber hoses can be used in the marine, mining, and chemical industries.
You’ll see many marine operations using rubber hoses. They generally use rubber hoses during the transfer of oil and gases on ships. It is worth noting that rubber hoses are made of multiple layers of rubber. This multi-layer design gives these hoses strength and durability. In this article, I have discussed everything about the rubber hoses and how they are manufactured.