Hydraulic hoses are among the most important components of a hydraulic system. Their use is common in a wide range of machinery. Their role is to transport high-pressure hydraulic oil within the hydraulic system. However, many people don’t understand the hydraulic hose basics. If you don’t understand the basics of hydraulic hoses, you’re at a loss.
During selection, choosing a hydraulic hose is crucial. However, if you don’t have basic information about them, you’re more likely to choose the wrong hose. This hydraulic hose will be unfit for your hydraulic system, resulting in a waste of your budget. In this article, I will discuss everything you need to know about hydraulic hoses. You’ll learn about its construction, types, laylines, and more. So, let’s get started.
Construction of Hydraulic Hoses
Before discussing construction, let’s have a quick overview of what hydraulic hoses are. These hoses are small tube-like structures that carry hydraulic fluid. They are made so strong that they can even withstand high-pressure hydraulic oil with ease. The use of hydraulic hoses is common in all machinery that relies on hydraulic systems to operate.
The strength of hydraulic hoses is due to their efficient construction. All the hydraulic hoses are made in three layers. These include:
- Inner tube
- Reinforcement layer
- Outer covering or protective layer
First, the inner tube or layer is most important as it directly carries the hydraulic oil. In terms of construction, this layer is made of strong synthetic rubber. This rubber is inert, meaning it does not react with hydraulic oil. If it were reactive, it would react with oil, affecting its quality.
Additionally, this layer is made very strong to withstand high-pressure oil.
The most common material used to make the inner tube is nitrile (NBR) and thermoplastic materials. The next layer is the reinforcement layer, which makes the hydraulic hose resistant to high pressure. In this layer, steel wires are braided. In some cases, this middle layer also consists of fabric reinforcement. This fabric use makes the hydraulic hose less resistant to high pressure but also affordable.
Hoses with a compromised reinforcement layer are not suitable for high-pressure hydraulic oil. The last layer is the outer layer, which gives external protection to the hydraulic hose. This is generally made of rubber and protects the internal layers from UV rays. For hoses used at extreme temperatures, the outer layer may be made of EPDM or PTFE. This layer makes the hose resistant to harsh or extreme weather.
Types of Hydraulic Hoses (Based on Reinforced Layer)
As said above, a reinforced layer of hydraulic hose is very important. It makes hydraulic hoses very strong and can withstand high pressure. Remember, hydraulic hoses typically operate under high-pressure hydraulic oil in large machinery. So, a strong reinforced layer must be present. In the section below, I will discuss various types of hydraulic hoses based on reinforcement layers.
1- Braided Hydraulic Hoses
Braided hydraulic hoses are widely used in various hydraulic systems. These hoses come with two or three steel wires wrapped around the inner tube. These steel wires are arranged in a braided pattern around the inner layer. This pattern ensures the steel wires allow the hydraulic hoses to withstand high pressure with ease.
There are different types of braided hydraulic hoses. These include single-braided hydraulic hoses, double-braided hydraulic hoses, and so on. Below is the table showing a comparison of different braided hydraulic hoses:
| Type of Braided Hydraulic Hose | Reinforcement | Pressure Range |
| 1-Wire Braided | Single steel wire | Low around 2500 PSI |
| 2-Wire Braided | Double steel wire | Medium up to 4,000 PSI |
| 3-Wire Braided | Triple steel wire | High Above 4,000+ PSI) |
2- Spiral Hydraulic Hoses
These spiral hydraulic hoses are superior to braided hydraulic hoses. Why? The reason is that these hoses come with multiple steel wires wrapped around the inner tube in a spiral pattern. This spiral pattern gives the inner tube more strength. As a result, these hydraulic hoses can easily withstand a higher pressure of around 6000 PSI. One common feature of braided and spiral hydraulic hoses is the use of steel wires. However, steel wire wrapped within braided hoses is less than that of spiral hydraulic hoses.
3- Helical Hydraulic Hoses
As you know, hoses typically collapse when exposed to suction or vacuum. Such hydraulic hoses also kink, which affects their durability. However, helical hydraulic hoses are resistant to suction and remain in good condition under vacuum. They come with a helix-shaped pattern of steel wire around the inner tube. This pattern makes these hoses very strong and kink-resistant. Remember, helical hydraulic hoses are generally not ideal for withstanding high pressure.
4- Textile Reinforced Hydraulic Hoses
These hydraulic hoses come with fabric layer reinforcement in the middle layer. In other words, polyester or nylon material is wrapped around the inner tube. Braided hydraulic hoses have steel wire braiding. In contrast, textile reinforced hoses have fabric braiding. What makes these textile-reinforced hydraulic hoses stand out is their flexibility. This flexibility makes these hoses more durable, even in winter conditions when hoses become stiff and break. However, these hoses are not rated to withstand very high-pressure hydraulic oil.
What are Laylines in Hydraulic Hoses?
Laylines in hydraulic hoses are markings present on the outer layer or covering of the hoses. These small, continuous lines help identify the hydraulic hose brand, size, and so on. Without these laylines, it would be very challenging to identify the hydraulic hoses. You’ll have to read the user manual to identify the hoses.
Laylines make life easier for both customers and sellers. How? These lines marked on the covering of hoses provide a wide range of information. By understanding it, you can easily identify the hose’s quality and its size. Most of the hydraulic hoses have a layline which provides the following information:
- Brand & Manufacturer’s name
- Hose size (inner diameter)
- Pressure rating (Typically in PSI)
- Working Temperature range
- Standard Followed in its making (such as SAE or ISO)
This information is very useful in analyzing and assessing the quality of the hydraulic hoses. As you know, hydraulic hoses of various sizes are available in the market. Just by looking at laylines, you quickly know the size. What I like about laylines is their permanent printing. They are not present on labels that could be peeled off. Instead, they are marked on the surface of hoses so they remain there for a long time without fading.
What is the Pressure Rating of Hydraulic Hoses?
The rating of hydraulic hoses means their working pressure. It is the maximum pressure a hydraulic hose can withstand during use. Hoses made with more braided wires have higher pressure ratings, and vice versa. Hydraulic hoses with higher pressure ratings can be used in heavy-duty applications, and vice versa.
It is worth noting that hydraulic hoses, if exposed to pressure beyond their limit, can fail. As a result, the entire hydraulic system won’t work, hindering the operation of the machinery. Therefore, hydraulic hoses must be used as per their pressure rating. If a hydraulic system uses high-pressure hydraulic oil, you must choose a hose with a high-pressure rating.
In terms of pressure rating, there are different types of hydraulic hoses:
- Low-pressure hydraulic hoses
- Medium-pressure hydraulic hoses
- High-pressure hydraulic hoses
Low-pressure hydraulic hoses are only suitable for low-pressure applications. If such hoses are used under high-pressure conditions, they are more likely to leak or, in the worst case, burst. Below is the table giving you the types of hoses in terms of pressure ratings and their use cases:
| Pressure Level | Pressure Range | Use Cases |
| Low | Up to 300 PSI | Return lines, lubrication systems |
| Medium | 300–3000 PSI | Industrial hydraulics |
| High | 3000–6000+ PSI | Heavy machinery |
How to Choose the Right Hydraulic Hose?
As I said above, a wide range of hydraulic hoses is available in the market. Some of these hydraulics are affordable but compromised in quality. In contrast, some hydraulics are very expensive. So, selecting the right hydraulic hose that is both of good quality and affordable can be difficult.
In the section below, I will discuss various factors to consider when choosing hydraulic hoses. Considering them will help you buy the right hydraulic hoses that work for years.
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Pressure Rating
First, you should always consider the hydraulic pressure rating before selecting a hydraulic hose. For heavy-duty machinery, choosing high-pressure hydraulic hoses is best. In contrast, medium-pressure hydraulic should be a choice for mild applications. Remember, choosing the wrong hose for high-pressure applications may result in leakage and a burst of your hydraulic hose.
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Correct Hose Size
The correct size of the hydraulic hose is another important consideration. Choosing those of narrower diameters is never a good option. Such hoses restrict the flow of hydraulic fluid. As a result, the hydraulic system may not work efficiently. I recommend selecting hydraulic hose diameters based on your hydraulic systems’ needs.
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Temperature Range
Some hydraulic hoses are only suitable for use within a normal temperature range. If the temperature is too low or too high, these hoses are inefficient at their work. You should always avoid such hydraulic hoses. Before selecting, you should check how well the hose performs at high and low temperatures. It should not become stiff if the temperature gets too low (in winter).
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Flexibility & Durability
Flexibility and durability are two other key factors one must consider when buying hydraulic hoses. Flexible hydraulic hoses are generally resistant to becoming stiff at low temperatures. Durable hydraulic hoses offer reliable performance for longer durations. In fact, it is ok to pay more for durable hydraulic hoses.
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Environmental Conditions
Hydraulic hoses can be used in a wide range of environmental conditions. These include humidity, dryness, rain, UV rays, and so on. Therefore, your chosen hydraulic hoses must be resistant to all these parameters. Hoses that are not resistant to environmental conditions are generally very fragile. The outer covering of hydraulic hoses must be resistant to both moisture and UV rays.
Conclusion
In conclusion, hydraulic hoses are important components in hydraulic systems. Without them, even large machines consisting of hydraulic systems become useless. Hydraulic hoses carry hydraulic oil (fuel) within the hydraulic system. In this article, I have discussed everything you need to know about hydraulic hoses.
You’ll learn about the types, laylines, and pressure rating of the hydraulic hoses. These types are based on the reinforcement layer type. It is worth noting that laylines are important markings present on the outer covering of hydraulic hoses. Without the laylines, understanding the hydraulic hose specification would be difficult. You’ll also learn about the pressure rating of these hoses.