How to choose hydraulic hose?

The correct selection of hydraulic hose is related to the working performance of the entire hydraulic system, so we need to comprehensively consider many factors such as pressure, materials, aꦰnd size.

1. Assembly code of hydraulic hose

Before formally understanding the design parameters of the hose, let's first understand why the hydraulic hose is always printed with a line of code, and what they represent.

In fact, printed on the hose is the hose assembly number, which is the order number when we buy 🌱the hose from the manufacturer, and these codes also show us information related to the performance of the hosဣe.

Now, let's see what we can learn from this list of code names.

ACME is the name of the manufacturer

Jupiter is the type of tube

170-04 is a hose model

1/4" refers to the diameter of the hose

🌄5𝓡000psi refers to the maximum working pressure of the hose

SAE100R2AT refers to the hose implementation standard, and there ꧅are three common hoseꦉ implementation standards, namely SAE, DIN and ISO.

Of course, the information marked by different manufacturers will be different, but the basic information of the maximum working pressure and hose model will be reflected. Because only if you know the hose model, you can find other more detailed information from the manufacturer's sample.

For example, based on the code name, we know that the h🔥ose is 170-04.

From𝓡 the sample, we can find out that the outer diameter of the hose, the minimum burst pressure, the minimum bending radius, the weight and so on are not reflected in the code.

2. Maximum working pressure

All hydraulic hoses included in the SAE standard have a maximum working pressure value and a minimum bursting pressure va💝lue. The minimum burst pressure is generally 4 times the maximum working pressure.

(Minimum burst pressure =4x maximum working pressur✤e)

Due to the impact load of the hydraulic system at work, when selecting ওthe hose assembly, it is necessary to ensure that the rated working pressure of the hose assembly is greater than or equal to the peak pressure of the hydraulic system.

(Rated ꦜworking pressure of hose ≥ peak press💎ure of hydraulic system)

Of course, with th𒉰e increase of pressure, the number of steel wire layers that the hose needs to use is more, and the price will naturally be higher.

The development speed of hydraulic hose is very fast, the textbook tells us that the maximum pressure pressure of the hose is generally about 40MPa, but in the hydraulic testing industry, the pressure of more than𒐪 400MP📖a hose is also more common.

The maximum working pressure of the hose is not difficult ⛄to find in the assembly code, because it is the only value with a pressure unit, for this hose, 5000psi is its maximum working pressure.

If this hose is selected, the rated pressure of the hydraulic system can onlജy be less than 5000/1.5, which is about 3333psi.

5000/1.5 material 3333 psi

Note, ℱdo not choose the maximum working pressure below the rated pressure of the hyd💟raulic system hose, which may have a fatal risk.

In addition, although the burst pressure of the hose is often four times the maximum working pressure. But that doesn't mean you can make the hose work anywhere near the burst pressure, you're risking your life.

(Rated pressure: can be called continuous working pressure, that is, under the pressure of ♉the hose can continue to work.

Maximum work𝓡ing pressure: can be referred to as th꧙e allowable pressure under short impact.)

3, hose material

The choice of hos🍰e material is also related to many factors, such as chemical compatibility with the fluid medium, the temperature of the internal conveying medium, the external ambient temperature, aꦇnd so on.

We know꧋ that hydraulic hoses are made up of mu♛ltiple layers,

The innermost layer is called the inner rubber layer, which is directly in contact with the fluid medium, 💃so the chemical compatibility between the inner rubber layer and the fluid medium should ᩚᩚᩚᩚᩚᩚ⁤⁤⁤⁤ᩚ⁤⁤⁤⁤ᩚ⁤⁤⁤⁤ᩚ𒀱ᩚᩚᩚbe considered;

In the middle, we are called the ꦇreinforcement layer, that is, the braided insulation layer, which is composed of one or more layers of fiber or steel wire braided, and the hose mainly relies on the reinforcement layer to withstand pressure;

The outermost layer is called the oute꧃r rubber layer, which protects the hose from external oil, chemical erosion, physical scღratches and other factors.

In some specific occasions, the hose may also be req⭕uired to have high temperature resistance, low temperature resistance, flame retardant and so on.

4. Diameter of hose

In order to minimize the pressure loss of the system 🌌and avoid excessive heating of the oil, the size choice of hoses and joints is also very important.

As shown in the figure

I.D.(InnerDiameter) : indic▨ates the inner diameter of the hose.

O.D.(Outer𝓰Diameter) : indicates the outer diameter of the hose.

So the question is, how do we get information about the inside diameter of the hose? Do you measure with a caliper? It's nice to think. You can't measure a hose with a clamp on both ends.

In fact, as already s🌠aid, the hose assembly code will directly tell us what its inner diameter is. For example, the inside diameter of this hose is 1/4 inch.

With the development of techཧnology, manufacturers are gradually improving the packaging proces🐲s of hoses. Compared with two hoses of the same inner diameter, the price of a small outer diameter will be higher, because it is lighter in weight and the minimum bending radius is smaller.

About the ⛄minimum bending radius, and how to choose the right path in the design, we will ta🍌lk about it later.

5. Length of hose

After the high-pressure oil is passed into the hydraulic hose, under the action of pressure, the length of the hose will change, and the change ra𒊎nge can reach about -4%~🐼+2%.

Therefore, when considering the length of the hose, it is necessary to leave enough free length, that is, the sagging amount. In general, the droop quantity L≥1.5D (D is the outer diameter of the h☂ydraulic hose).

Of course, the hose can not be too long, too long hose will increase the flow resistance, resulting in an increase in oil heat, reduce the efficiency of the system. And it's easy to trip over.

Of course, if there is a relative d🎃isplacement between the two connection points, then youﷺ do want to make sure that the hose is long enough to ensure the relative motion between the two objects.

Hose too short will not work, if the hose is too tight, the hose will be deformed when🍸 connected, this deformation will cause some parts of the inner diameter narrow, also will reduce ﷽the efficiency of the system.

Another reason is that when the hose is pressurized, the h🍸ose that is too short may deta🐬ngle from the joint impound.

The correct approach is to ensure that the hose begins to bend at a certain distance from t✨he buckle joint, and this distance should be at least twice the outer diameter of the hose.

Choose the right hydraulic pipeline for the equipment, the following points can be used as 🅠a basis, hope to help you:

1. Size of rubber hose. The inner diameter of the pipe affects whether the flow medium of the equipmen𒉰t can be unimpeded; When the hose is fixed with a hose clamp or the hose is passed through the steel plate, pay attention to 🧔the outer diameter of the hose.

2, hose pressu💫re. Select the matched pipeline pressure according to the working pressure of the equipment. Due to the impact load of the hydraulic system, the maximum working pressure of the hose is generally greater than the maximum working pressure of the hydraulic system, and the blasting pressure of the hose is generally 3ー4 times the maximum working pressure.

3, the transmission medium and the use of the environment: to choose the corresponding hydraulic hose, such as: the transmission medium is hydraulic oil, then choose the hydraulic oil resistance; Select the hose according to the use environme꧂nt, see whether the environment is harsh, whether it is open air, light time, whether it is frequent friction, external temperature, etc.

4, minim💜um bending radius: Because the h🃏ydraulic hose should not exceed the minimum bending radius when in use, it is necessary to consider the specific location of the product using the hydraulic hose to determine the appropriate minimum bending radius