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There are many reasons why you may be experiencing a leaking hydraulic hose. In this post we’re going to cover the process of how to identify it so that you can then replace it in order to continue working with your equipment.
Before we get started, it’s important to know that in these modern times, hydraulics are used to power an incredible number of industrial machinery. From car brakes to subsea pumping stations, the hydraulic and its hose provide a powerful link between industrial output and activity and power.
However, after extended use, the hydraulic hose can be put under stress or even environmental conditions that are not conducive to it having a long life span. Failures can occur that will bring any output to a grinding halt. However, keeping an eye on the condition of hydraulic hoses can be just as challenging as fixing them.
Let’s identify what the problem is with the hydraulic hose
First off, you’ll need to gather some tools. You’ll need a spanner that is the same size as the nuts on your machinery. A pair of goggles, a pair of heat resistant gloves, lubricant and some hydraulic caps: With that, you’re ready to discover what’s holding up your output.
The first task on your hands is to discover where the leak is. This could be very tricky. Many hydraulic hoses are hidden and buried inside machines. Others are located in very tight spaces, or placed close to awkward corners. They can also cross paths, leaving you confused about where they are coming from. The most sensible start in your quest to locate the leak is to dry the machine where the leak is coming from. Then you can put on your safety goggles before pressurising the system to gain an understanding of where the fluid is leaking.
Depressurize the system
Once you have established where the leak is coming from, it’s time to depressurize the machine. You will need to turn off anything in the engine that may move the fluid in the pipes, in addition to discharging the pumps.
Once you have depressurized and confirmed which hose and where the failure has occurred, it’s time to remove it. Start by taking off any hose clamps or any custom fittings and remove the hose. Fit the hydraulic cap into place quickly to prevent any leakage. Do the same at the other end of the hose, and then get ready to add the new one. You’ll need to check it’s in good condition and clean. Blast some compressed air over it, and then attach and pressurize again. You should now have got rid of your leak.
Anytime there is a failure with a hydraulic system hose, it’s important to understand what went wrong so that it can be avoided in the future.
There are a number of reasons that a hydraulic hose can fail. Often it can be something like an ill-fitting component, incorrect assembly or installation or a combination of all three. However, whatever the cause, quite often all failures can be avoided by implementing proper procedures.
Let’s explore the most common causes of hydraulic hose failure:
Issue #1. The component has been blown off
Reason: This is due to the hose not being put deep enough into the fitting. The purpose of the grips in the shell is to hold the fitting tightly onto the hydraulic hose. It’s quite often that last grip that makes all the difference for a strong hold.
Solution: Check the manual to determine if there is a recommended insertion value for the hose, if so, mark the hose appropriately. Insert the hose – you might want to use an insertion-depth gage.
Issue #2: The hose is brittle and the cover of it cracks when it’s flexed. The cover may also look to be dried out and charred in addition to the assembly retaining its installed shape once removed.
Reason: the hose has had heat over the recommended temperature for it. This has resulted in the elastics and plastics lsoing their flexibility. Cavitation can also create this situation.
Solution: Decrease the temperature of the fluid. Replace the hydraulic hose with a model that is built for hotter temperatures. You may also need to review the heat of the fluid to understand whether it can be run more efficiently with a heat exchanger.
Issue #3: Leakage may have blown off the fitting from the hose.
Reason: The shell was not fitted well enough; there may have been either too much or too little crimping during assembly.
Solution: Replace the hose assembly. Check for proper fitting usage and review instructions of the crimping machine being used — including the proper tool.
Issue #4: Burst hose and the wire reinforcement has failed.
Reason: The end of the service life has been reached by the hydraulic hose. It could be that it’s worked through a number of high pressure cycles which caused the hose to flex too much in one spot.
Solution: review how it’s used and replace as appropriate.
Issue #5: The hose either leaks or has bubbles appearing on the cover, close to the fitting.
Reason: It’s possible that the hose was either cut or damaged on its inner tube during the fitting. This may have been caused by not using enough lubrication and moisture has entered around the fitting’s socket.
Solution: determine what needs to be replaced and replace it.
Issue #6: On the external cover there is damage with either twist of broken wires.
Reason: There was not enough lubrication during fitting and the hose was twisted.
Solution: Review how the hose and fitting should have been assembled. Replace the hose and add clamps if necessary. Ensure that the hose will only flex in one spot.
Issue #7: The hose has completely burst, the cover is either torn or deteriorated and the damaged reinforcemeent wires are being displayed .
Reason: The hose has been rubbing either against sharp corners, other hoses or brackets. Alternatively the clamp size is wrong.
Solution: Replace the hose, and use a protective hose guard or shield. Use clamps to prevent the hose rubbing against other objects.
Have you had issues with hydraulic hoses failing? What have you done about it?
How long can you expect your hydraulic hose assemblies to last before they need to be replaced or undergo some type of repair? As with any type of maintenance work, there isn’t a clear answer to this question. Fortunately, however, there are some clear signs that can be recognised in order to identify when it’s time to make a repair so that you can avoid a replacement. Let’s explore the options:
According to most engineers, a rubber hose can last for 10 years from its manufacture date. This date is most often printed on the hose itself. If it’s more than or close to the 10 year mark, then it should not be used. Buying a new hose assembly is far more cost effective than needing to fix the potentially dangerous and costly results from a blown or broken hose.
It’s recommended that hose assemblies undergo a visual inspection every month with a full replacement of them every 12-24 months. Kinking, abrasion or crushing is the cause of 80% of all blown hoses and this can be prevented by taking a quick look at the condition of them.
As part of the maintenance schedule, it’s a smart idea to keep a detailed record of all hydraulic hose assembly replacements and failures. This can then be referred to in order to establish an estimate of what to expect and when to replace etc. However, nothing compares to the protection that can be gained from regular visual inspections.
When it comes to hose assemblies that are critical to the functioning and operator safety of equipment, they should be replaced on a more frequent schedule.
Hose assemblies should also be replaced if any leaking oil is seen close to fittings or if there is any abrasion, crushed or cracked hoses found. You should also look for exposed wires and corroded fittings.
In summary, visual inspection is key and following a maintenance schedule can go a long way to prevent breakages and other blow out incidents.
When specifying the size (diameter) of hydraulic hoses it is vital that the right calculations are done to obtain the correct size of hose. Too narrow and the pressure in the hose will cause damage to the seals and increase the pressure of the liquid flowing into a chamber. Too wide and there will not be sufficient pressure in the hose for the liquid to flow at the right rate – it will move too slowly and may even back up, never reaching the intended destination.
The traditional way of determining the correct hose size is to use nomograms and a ruler or a calculator and some complicated formulae. As with any process where human input is required there is scope for human error, which could be very costly to correct if a custom piece of machinery has been built on the basis of incorrect hose size calculations. Sergiy Sydorenko of Insane Hydraulics, has built an online interactive tool for hydraulic designers and engineers that will be invaluable when deciding on the correct hydraulic hose size. It can be found here for those who are interested in taking a little shortcut on their calculations, or for those who want an accurate resource against which to check their manual calculations.
The interactive tool allows you to specify the flow rate and speed needed, and then uses these numbers to define the correct size of hydraulic hose. Annotations on the tool show the maximum recommended velocities for different types of line, so if you need to adjust the flow rate to make it work for a particular size of line this is also possible using the tool – it will tell you the right flow rate for any size of hydraulic hose. This is one online tool that should be in the bookmarks of every hydraulic engineer.
Next time you cut a hose for your hydraulic system, there’s something that you need to know. Each time you use a blade on the wire reinforcement it’s going to create metal particles or some type of dust from the friction and cut on the outer or inner lining of the hose. This can introduce contamination in your circuit.
Fortunately, there are ways to do hose cutting that will reduce the risk of contamination such as using a wet blade as opposed to using a dry one. Either vacuuming or blowing air through the hose could also remove dust. Of course, when a long length of hose is cut, or when out in the field this might be difficult to do.
It’s important to do all that is possible to remove the cutting residue, or any other dust or contamination that could be in the hydraulic hose – before you install it. One of the most popular ways to do this with most hydraulic engineers is to blow through a foam cleaning projectile.
The manufacturers of this solution claim that it’s possible to achieve very clean hoses from using these products. As with anything else, it will depend upon a number of things as to whether this achieves this promised cleanliness. For example, it’s important to use a projectile that is of the same size as the hose being cleaned. In addition it will depend upon the number of shots used and whether you use a dry or solvent wetted projectile. If you’re planning on crimping the ends, ensure that the projectile is performed prior to that action.
These days we understand that most hydraulic hose fabricators have access to hose cleaning projectiles. However, it’s another matter with regards to how thorough they are with their cleaning. If you are looking for very clean hydraulic hose assemblies, it’s something that you must specify to the manufacture.
Recently one of our clients told us that he received a hydraulic hose from a manufacturer and he checked it by pouring solvent into it before he installed it, he was absolutely flabbergasted by the amount of dust and other rubbish that came out. Be sure to check your hydraulic hoses before installing them.
Hydraulics has been around for a very long time. But are you aware of how far it has actually come? You wouldn’t be alone if you responded with no. It is a very technical subject that can be quite difficult to understand, but in this article we want to tell you the story of hydraulics! We want to share with you who discovered hydraulics, what it was originally used for and how hydraulic power got to where it is today.
So why don’t we start at the beginning! Where does the word hydraulic come from?
The word hydraulic originates from the Greek word ‘Hydros’ which means water. Why water? Well, this is because water was the first liquid to be used in the hydraulic system. Today, hydraulics includes the physical behaviour of all liquids, not just water.
There are four main types of hydraulic valves that Hydraproducts offer, all of which are compliant with CETOP standards. Hydraulic valves that are recognised by CETOP are interchangeable within most types of hydraulic equipment, making it easy to find a supplier that can provide valves suitable for use in your hydraulic equipment.
Valves in hydraulic equipment control and regulate the flow of hydraulic fluid through a system, but as there are different requirements for fluid flow in certain applications it is important that the right valve is used for each purpose. Flow control valves can be configured to regulate the flow of fluid in two directions and are adjustable to allow for fine tuning of the flow rate. They control the movement of fluid in one direction, but in reverse the flow is free and cannot be regulated in the same was as it is when flowing forwards. A pilot operated check valve is used to control the flow of hydraulic fluid to a cylinder, stopping it when needed to prevent unwanted movement of the cylinder. A pressure relief valve is often used in conjunction with a pilot operated check valve or a solenoid valve to release the pressure contained by a pilot operated check valve, or to limit pressure in a control line leading to a solenoid valve. Our solenoid valves have a four-landed control spool and are used to change the direction of fluid flow. They are all rated to ISO4401-03-02-0-94 and DIN 240 340-A6 and can handle a flow rate of up to 60 litres per minute and pressures up to 320 bar. With a distribution network covering the UK, Germany, Australia, New Zealand, Finland, Lithuania and Bulgaria our hydraulic valves can be delivered to a wide range of locations very quickly.
Solenoid valves are often chosen over flow control valves for their ability to regulate the directional flow, instead of only being able to regulate in one direction. A flow control valve is suitable for applications where movement of a cylinder in one direction needs to be carefully regulated, but when it returns to the starting position no control is needed over the flow and speed of movement. They can be mounted in either direction, so it is up to the user which direction requires the control. For applications where control is needed over the flow rate in both directions (for example, in technologies that open and close gates or doors at a set speed) a solenoid valve is better as it allows for that fine control of movement and speed in both directions.
In most cases a hydraulic valve will be replaced with one of the same type, and buying from Hydraproducts ensures you will get a valve that is ideal as a replacement even if your equipment is made by a different manufacturer. Sometimes a hydraulic valve needs to be replaced with one of a different type when machine specifications or usage changes, an example being a piece of machinery that used to use a flow control valve, but where there are operational advantages to having better control over the hydraulic flow in two directions.
Choosing the right type should be easy when replacing a valve, as you can use the same type as before, but when designing a new piece of hydraulic machinery, the decision is a little harder. Understanding the basic function the machinery is required to perform is a must, but going a little further into the other functionality that may be required, or thinking about performance improvements that could be made with a different type of valve can inform a better design and result in hydraulic machinery that is more user friendly or that can fulfil more than the basic functions specified at the design stage.
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