How to select high quality hydraulic hose - 4 ways ...

The quality of the hydraulic rubber hose is directly related to the safety of the use. So it is very important that how to determine whether the quality of the high-pressure pipe hose is qualified.

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High-pressure rubber hose usually consists of four layers: outer rubber layer, steel wire reinforcement layer, middle rubber layer, and inner rubber layer.

1. The inner rubber layer directly touches the hydraulic oil, usually made of synthetic rubber.

2. The bearing capacity of the flexible hose depends on the reinforcement layer. This layer is the skeleton of the hose pipe, which is usually woven or wound with steel wire.

3. Most medium and high pressure use steel wire woven body as the skeleton, and high pressure and super high pressure mostly use the steel wire to surround the skeleton.

4. The outer rubber layer is usually made of abrasion-resistant and corrosion-resistant rubber to ensure that the reinforcement layer is not subject to mechanical damage, chemical corrosion, wet rust. Used for oil return pipeline.

The inner and outer layers of the high-pressure hose wall are oil-resistant rubber, and the center is (2 to 4 layers) interspersed with steel wire or surrounding steel wire.

Poor quality hydraulic hose pipe will show:

1, the thickness of the braided hose wall is uneven; the steel wire is too tight, too loose, or the number of steel wire layers is too less;

2. The amount of deformation (elongation, shortening or bending deformation) of the pressure hose after adding pressure is large;

3. Poor air-tightness of the outer layer of rubber causes corrosion of the steel wire; poor sealing of the inner layer of rubber allows high-pressure oil to easily enter the steel wire layer; lack of adhesion between the rubber layer and the steel wire layer.

The above conditions will reduce the bearing capacity of the hose hydraulic, and as a result, the pipe will burst at the place of the thin wall, so you need to pay special attention during installation.

The following methods will help you identify the quality of high-pressure hydraulic hoses:

First: Observed

1. The appearance quality of the hydraulic hose:

The appearance quality of the hose flexible can not be ignored. It not only affects the appearance quality of the rubber hose pipe assembly and will affect the quality of use. If the outer rubber layer has air bubbles, pores or mechanical damage, the reinforcement layer is exposed, causing corrosion of the skeleton layer, reducing the compressive strength of the rubber hose hydraulic, directly affecting the crimp hose service life, and even accidents during use.

Therefore, attention should be paid to the appearance quality of the hose and appearance defects that affect the performance of the hose assembly should be eliminated.

The surface of the rubber hose is generally divided into two types: smooth surface and cloth pattern: smooth surface requires smooth, no air bubbles and alignment, etc., or there is an Uneven bump; There are gaps and the winding is not tight.

2. Look at the steel wire layer:

Quantity: Rubber hoses are generally divided into three layers, namely the inner rubber layer, the reinforcement layer, and the outer rubber layer. The reinforcement layer belongs to the middle layer. This layer generally adopts fiber, steel wire weaving or winding. The more layers, the more the strength coefficient (also related to the material and thickness of the reinforcement layer).

Also observe if the wire layer placement is whether uniform.

3. See if the rubber hose has eccentricity:

The rubber tube core is perfectly round under normal conditions. Under eccentric conditions, it may affect the use.

4. Look at the Curvature of the rubber hose:

After the hydralic hose is folded in half, look at the color change and rebound speed of the surface of the rubber hose. The color change is small and the rubber hose with fast rebound speed is generally of better quality.

5. Deviation of high-pressure flexible hose wall thickness.

Due to The influence of the overlap width of the middle rubber layer of the skeleton layer, May cause excessive hose wall thickness deviation. If the wall thickness deviation exceeds the allowable range, it will affect the subsequent sealing and pull-out strength, and even cause the hose assembly fittings to deviate (crooked head). Therefore, the deviation of the wall thickness of the hydrolic hose should be strictly controlled. Generally, If the wall thickness deviation exceeds 0.5mm, it should be chosen carefully.

6. Adhesion between the layers of the hidraulic hose.

High-quality rubber hoses should have good integrity, that is, there should be high adhesion between the structural layers, and the bonding between the rubber layers becomes a whole. In this way, it can meet the various process requirements in the process of fittings assembly and crimping, and can ensure the performance requirements of the hose assembly. Therefore, the adhesion between the various layers of the hose must be controlled not less than the technical standards, and every effort should be made to select a hose with high adhesion for the production of the hydraulic hose assembly.

7. See whether the inner wall of the rubber tube is lubricating, smooth. Use your fingers to poke. Is the inner rubber elastic? Good elasticity means high rubber content.

8. Dip in diesel and let it sit for a day. The next day, take it out to see if the inner rubber of the high-pressure hose has swelled, if the expansion coefficient is large, indicating that the rubber quality is not good. 

 Second: Measure

Measure hidraulic hose diameter and wall thickness: Good quality rubber hose has a uniform wall thickness, and spiral hose diameter is equal everywhere.

There is an actual deviation between the size in use and the size in production so that the inner diameter and outer diameter will fluctuate during normal work. If the fluctuation range exceeds the allowable range, there is no way to ensure the hose fitting crimping pressure uniform, it difficult to guarantee the quality of the hose assembly. Therefore, for the hoses used in assembly production, it is necessary to strictly check whether the inner diameter and outer diameter and the skeleton layer meet the requirements. For the outer diameter deviation, the requirements can be appropriately relaxed.

Hydraulic rubber pipe hose inner diameter measurement: Wire-reinforced hydraulic hose should be measured at least 25mm away from the end of the hose.

Measurement methods:

1. Measurement of rubber hoses with a nominal inner diameter of less than 150mm can be performed with plug gauges with a Increments of 0.25mm. Insert the plug gauge slowly into the excavator hose sample without applying pressure. When the lumen of the hose is not exactly round, it should be measured more carefully.

2. For hoses with a nominal inner diameter of less than 63mm, which require high accuracy, such as steel wire-reinforced hydraulic hoses, an Expansion ball style or telescopic inner diameter gauge should be used for measurement.

3. For measuring excavator hose with a nominal inner diameter of 100mm and below, it can be measured using the inner claw of a sliding vernier caliper that meets the requirements of GB.2. Take two measurements at right angles to each other and take the average as the inside diameter. Take care not to deform the hose during the measurement. When measuring hoses with a nominal inner diameter of 100mm or more, if the accuracy of the measurement result is required to be higher than that, you can use a suitable caliper to measure

4. For measuring all inner diameter hoses, the caliper specifications should be suitable for the inner diameter being measured. Two measurements should be taken at right angles to each other and the average value should be taken as the inner diameter.

Hose outer diameter measurement: Generally measured at both ends, because the size here directly affects the use of the assembly.

When measuring the outer diameter of the braided hose pipe with a caliper, you can use the full length of the claw to contact the outer circle of the hose in parallel. In this way, you can measure a long range outer circle at a time, and grasp the feel to obtain the reading based on the principle of "minimum contact force".

1. Measuring the outer diameter of the hose with an outer diameter measuring cylinder:

The measured outer diameter of the hose is generally below 50: When measuring, you only need to gently insert the hpipe rubber hose into an outer diameter measuring cylinder, with the "minimum contact force". The maximum and minimum size of the hose can be determined at one time Qualified. Fast and accurate; especially practical for some hoses that require 100% inspection of the outside diameter; if the hydraulic rubber hose flexible is out of roundness, it can also be rotated or lightly squeezed to eliminate the impact.

2. Outside diameter go-stop gauge measure the outer diameter of larger hoses: When measuring, insert the outside diameter go-stop gauges gently into the outer circle of the flexi hose with "minimum contact force", and you can determine at one time whether the maximum and minimum dimensions of the reinforcement hose Qualified, fast and accurate: If the hose is much out of round, you should make a comprehensive judgment in 2-3 directions, or immediately measure after the outer circle of the hose is properly rounded by hand: H1 should be larger than the manufacture hose diameter 3-5 mm , H2 should be equal to or greater than 2/3 of the high pressure rubber hose diameter.

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Third: smell

Smell the hose body, to check if with or without odor: the rubber hose material with less odor has better quality.

With the development of the rubber industry, various kinds of recycled materials such as factory scraps and experimental slag are increasingly used. If the rubber tube you buy has a large odor, it is very It may be the recycled material used. Recycled materials not only cause great irritating taste. If these recycled materials are used in large proportions, due to the fear of scorch during vulcanization, low temperatures or shortening the vulcanization time often lead to undersulfurization, which will not only affect the vulcanization effect, but also the quality of hydraulic hoses.

Fourth: test

Pressure test, Impulse test, etc.

Verification pressure test:

When using a verification pressure test to check if the hose assembly leaks, the applied pressure is twice the working pressure and the hold time is 3 minutes. During this period, the test piece should be inspected for signs of material, processing uneven leaks, cracks, and other signs of damage to the product. This test is used as a mandatory inspection item for TOPA factory inspection. Note: The high pressure hose rubber must not be bent during the experiment.

Pressure bear deformation test: Hold for 1 minute at the specified pressure (working pressure, verification pressure or other pressure lower than verification pressure), measure the length and outer diameter change of the hose high pressure, and the twist angle and bending

Burst pressure test: Determine the pressure of the hydraulic hose high pressure when it bursts at the specified boosting speed

Leak test: Store under static pressure of 70% of the minimum burst pressure for 5 minutes and repeat it once to check for leaks or damage. Because the test often uses water, and the viscosity of the actual liquid is different, the burst pressure and leakage pressure measured at room temperature may be slightly lower.

Bending test:

After bending the tube hose to a certain degree, measure the ratio of the minimum outer diameter of the bent part to the outer diameter before bending, the steel ball passing capacity and the bending force when the tube is pressurized.

Pulse test:

The design of the rubber tube itself is used for gas or liquid transportation. This determines that the rubber tube must withstand a certain pressure strength. The rubber tube pulse test can simulate the use environment of the rubber tube, such as pressure, temperature, humidity, flow rate, corrosion, etc. From the data obtained, the rubber tube quality and fatigue life can be deduced. Troubleshoot related security risks.

It is required that after the specified total number of pulses is completed, the rubber flex hoses cannot fail so that it can be regarded as a pass.

The rubber flexible rubber hoses pulse test can be performed intermittently as long as the number of continuous pulses can be determined. Of course, this is a destructive test. After testing, the rubber hoses braided will be discarded.

The quality of the hydraulic hose directly determines the safety of the consumer. Therefore, we must choose qualified products to prevent fake and shoddy products, avoid bringing hidden safety hazards to the user.

The stable quality of hydraulic hose is the first requirement for TOPA hydraulic hose manufacturer workshop production. By managing the process parameters and operating methods of the hydraulic hose production process to achieve the purpose of stabilizing the quality of the hose product. It is professional to ensure the quality of hydraulic hoses during production. In article&#;Hydraulic hose assembly failure analysis&#;, we will show you what leads to hose assembly failure.

Do you have other questions about choosing high quality hydraulic hose? Feel free to contact TOPA rubber hose manufacturer.

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Hydraulic hoses are taking a more and more important role in mobile vehicles and fixed production lines, and mechanical power transfer fields these years, hydraulic hose guide is necessary due to the improvement of automation control level and efficiency of modern equipment.

In simple terms, a hydraulic system uses liquid fluid &#; hydraulic fluids &#; to generate work. A lift, for example, can carry heavy loads from one point to another periodically under the power of the pressurized hydraulic fluids.

Hydraulic hoses accommodate hydraulic fluids and sustain the pressure and transfer the periodical pressure to the motion of the actuators. they can find their application in construction, agriculture, mining machine, etc.

In this article, as a professional hydraulic hose manufacturer, I will walk through all the hydraulic hoses we supply into some categories and help you figure out the popular hydraulic hoses used in the current market.

What are Hydraulic Hoses?

Hydraulic hoses are made from some polymer such as synthetic rubber, thermoplastic, or PTFE, to accommodate hydraulic fluids and transfer the power from the power creator (pump) to actuators. Hydraulic systems are vital units for some mechanical equipment.

Hydraulic hoses can sustain certain pressure lies in they have a reinforcement layer in the middle, the reinforced pattern includes fiber braided, steel wire braided and steel wire spiral wound. Different reinforced patterns result in different pressure ratings of hydraulic hose.

The hydraulic hose structure statement can guide you on how to choose the right hydraulic hose.

General hydraulic hoses consist of three fundamental layers from the inner to the outside on the analysis of the cross-section of the hose. Each of these layers plays an important role in ensuring the hose works optimally:

• The inner or core layer ensures the hose is chemically compatible with the hose. It is the only layer that has direct contact with the hydraulic fluid, and if not chemically compatible, it could easily damage.
• The reinforcement layer acts as a support to the inner layer. The inner layer may be chemically compatible with the fluid but not strong enough to withstand its pressure. Thus, the reinforcement layer is what helps the hose withstand pressure.
• The outer layer is the external part of the hose &#; the part you see and touch. It ensures the hose doesn&#;t get damaged &#; punctured or melted by heat, for example &#; from the outside. So, it has to be compatible with the working environment.

Types of Hydraulic Hoses

Hydraulic hoses have different types of classifications. The three most common classification types, however, are material, standards, and reinforcement.

• Types of Hydraulic Hoses By Material

Hydraulic hoses typically come in rubber, thermoplastic, or Teflon material. The most common is rubber, which is popular due to its high compatibility with many hydraulic fluids. Rubber&#;s flexibility is also an advantage.

A rubber hydraulic hose comes with a rubber inner layer and outer layer. But the reinforcement layer is typically made with wire steel braids. The number of braid layers determines how much pressure the rubber hose will handle.

Thermoplastic hydraulic hoses are lightweight, flexible, clean, and non-conductive. They come with a nylon inner layer, a synthetic fiber reinforcement layer, and a polyurethane outer layer.

The third material, Teflon, makes a hydraulic hose that will not corrode. At least, not under normal circumstances. They come with stainless steel braid reinforcement later, and most come without an outer layer.

Teflon hydraulic hoses are popular for high-temperature applications. They also have good chemical compatibility, like rubber.

• Types of Hydraulic Hoses By Standards

General hydraulic hose standards fall into two series: SAE J517 and DIN EN standards.

SAE is the abbreviation of the Society of Automotive Engineers, hydraulic hoses that comply with SAE standards are popular in North America. the common types are listed in the table below.

DIN EN is the abbreviation of Deutsche Industrial Norme and European Norm, this standard originated in Germany and was adopted by European Norm. The hydraulic hoses which adhere to EN have similar requirements to that in the SAE, so some hoses can meet the two standards at the same time.

StandardsMaterialReinforcementInstances PatternNum. of Layer SAE J517RubberSteel wire braidSingleSAE 100R1AT TwoSAE 100R2AT Single or twoSAE 100R17 SingeSAE 100R5 Textile braidSingleSAE 100R3 TwoSAE 100R6 Single and Helical steel wireSAE 100R4 Wire spiral woundFour SAE 100R9 SAE 100R12 Four or sixSAE 100R13 Four or sixSAE 100R15 ThermoplasticTextile or wire braidSingleSAE 100R7 TwoSAE 100R8 PTFESteel wire braidSingleSAE 100R14 ENRubberSteel wire braidSingleEN 853 1SN TwoEN 853 2SN SingleEN 857 1SC TwoEN 857 2SC Wire spiral woundFour or sixEN 856 4SP EN 856 4SH

• Types of Hydraulic Hoses By reinforcement

If you are aware of the hydraulic hose structure, you will know the importance of the reinforcement, in hydraulic hoses, the reinforcement layer is the source of the working pressure rating, the reinforcement layer comes in textile(fiber) braided, steel wire-braided and spiral wound steel wire from low-pressure to high-pressure resistance for a hydraulic hose.

How To Choose the Right Hydraulic Hose

The right hydraulic hose will depend on your hydraulic system. And when weighing your options, here are five tips to follow:

1. Ensure the hydraulic hose material is chemically compatible with the fluid you want to convey. If you are conveying hydraulic oils, for example, synthetic rubber hoses would do justice. 
2. Ensure the working pressure of the hydraulic hose is above the actual pressure, even temporary pressure spike must be below that. Working pressure refers to the amount of pressure the hose can handle without any problems.
3. Consider the dimensions of your hydraulic system. In particular, consider the required length, inner and outer diameter, and bending radius. These will determine the right hydraulic hose size to use. And it is the most important because a wrongly sized hose will serve no purpose.
4. Examine the hose&#;s end connection. Some hoses come with pre-made fittings, while others are universal. Hoses with pre-made fittings are usually more advantageous. But if you opt for them, you must ensure the fittings are compatible with your hydraulic system.
5. Choose a hydraulic hose that supports the accessories you will need. Most hydraulic systems need select accessories to connect the hose to other parts. Hose clamps, crimpers, and, of course, fittings are some examples.

Conclusion

Many people find it difficult to choose the right hydraulic hose. It is not surprising, considering all the technicalities involved in making the choice. Thankfully, the above hydraulic hose guide will make the task easier for you.

When you decide on the right hose type and size, you must purchase from a trusted hydraulic hose manufacturer. Your hydraulic hose may be the perfect size and still underperform because it is low quality.

This is why at Sinopulse we prioritize manufacturing top-rate hydraulic hoses and fittings. Let us help you find the best hydraulic hoses in the market by getting in touch with us today. 

Contact us to discuss your requirements of en856 4sh factory. Our experienced sales team can help you identify the options that best suit your needs.