Hydraulic hoses are key components of every hydraulic system. They are commonly used in small to large machines that use hydraulic power to operate. However, pressure build-up inside the hoses is common and must be released. If not, this pressure can lead to unwanted accidents. But the question is: How to relieve pressure on hydraulic hose?
Interestingly, releasing build-up pressure from the hoses is an easy task. With the basic information, you should be able to do the job. However, slight mistakes can lead to wearing hydraulic parts or accidents, causing injuries. Fret not! In this article, I will explain different ways to release the pressure from hydraulic lines. So, let’s get started!
Why Is Releasing Pressure from Hydraulic Hose Important?
When the hydraulic system works, fluid flows through these hydraulic hoses. Right? The fluid flow is fast, providing enough energy for machines to work. When we switch off the machine, some pressure from the fluid gets stuck in the hoses. This is called residual pressure, which does not go into a hydraulic tank or escape from a hose.
Here are key reasons why removing the pressure on the hydraulic hose is essential:
- A pressurized hose can pose serious issues when you have to disconnect the hose from the fitting for its maintenance.
- The hose, with its extreme pressure fluid, can cause accidents when suddenly removed. If such fluid gets on the skin, it can cause injuries and skin burns.
- Consistent pressure inside the house is also not good for the hydraulic system. It can damage the hoses’ joints, seals, and other parts. If the pressure is very extreme, it can even negatively impact hydraulic cylinders and pumps.
- Consistent stress on the hose can also cause leakage. If the hoses remain under pressure, they weaken over time, resulting in cracking.
In short, releasing pressure from the hydraulic hose is crucial. Remember, the pressure inside the hose can sometimes be up to 2000 PSI. This can damage the interior components and be dangerous for workers who disconnect such pressurized hoses. The conditions can be even worse if the hydraulic hose remains at a high temperature.
How to Relieve Pressure on Hydraulic Hose?
As I said earlier, relieving pressure on a hydraulic hose is straightforward. However, it requires basic know-how to get started. There are generally three ways to release the pressure. In the section below, I’ll explain each of those methods.
1- Using the System’s Built-in Relief Valve
Modern hydraulic systems come with built-in pressure relief valves. This valve makes life easier and reduces the hassle. They come with a pressure gauge and lever. The pressure gauge helps you see the exact residual pressure inside the hose. On the flip side, the lever helps adjust the pressure. Some hydraulic systems also come with knobs which work the same as levers.
First, check the pressure and note the pressure of the hose. If the gauge shows zero pressure, you don’t need to do anything except unplug the hose. Conversely, if the pressure gauge shows some pressure, you will release it from the hose. For this, turn the lever from a closed to an open position. When you open it, it will give pressure a passage to escape from the hose.
When the lever is in an open position, check the pressure gauge. You’ll see the pressure reducing the pressure gauge. You can close the lever once the pressure on the indicator becomes zero. Similarly, if the hydraulic system has a knob, you will have to rotate from close to open position. These built-in pressure relief valves generally come in advanced hydraulic systems.
2- Operating the Control Valves to Release Pressure
The hydraulic system comes with a control valve. This valve is key as it regulates the flow of hydraulic fluid. When this valve is open, it ensures 100% fluid flow. On the flip side, partial close values indicate reduced flow. If the valve is closed, the hydraulic fluid doesn’t flow, and the machinery won’t perform the task.
This valve comes in handy for removing the pressure on the hose. First, switch off the machine. The hydraulic system should not be in use or under stress. Now, open and close the control valve quickly. This opening and closing will help pressure escape from the hose. The fluid will go into the fluid tank or reservoir. You can use it when the hydraulic system does not have a pressure relief valve.
3- Loosening Hose Fittings Carefully
This method for removing the pressure can be risky. However, it can prove helpful if no other method helps. As you know, we must remove pressure when a hose requires maintenance. We unplug or disconnect it from the hydraulic system by loosening the fittings. Right? Wear safety gloves and gently loosen the connection point (fitting) of the hose.
It is essential that the fitting be loosened slowly and carefully. First, stay on one side of the hose and use a rag on the connection point. Then, start loosening it. This will allow some trapped pressure inside the hose to escape. Once the pressure is reduced to some level, you should lose the connection point again to more extent.
By doing this multiple times, you’ll be able to remove all the pressure on the hose. However, this method is hazardous. The fluid inside the hose can burn out quickly if you excessively loosen the connection point. The pressure burst can be so harsh that it can cause skin burns. Therefore, you must wear safety goggles and gloves and use a rag to reduce the risk.
Precautions & Safety Protocols for Hydraulic Hose Pressure Relief
As I said, relieving the pressure on a hydraulic hose can be risky. Therefore, there are some safety protocols that you should follow. Ignoring them can sometimes be lethal, especially if you’re a newbie. Here is the list of those precautions:
- First, you should use safety goggles and gloves when removing pressure. In this way, fluid won’t go into your eyes. In case of a hose burst, your hands will be safe from skin burns.
- You should not stand in front of the hydraulic hose during the process. A slight mistake can cause a burst or leakage of the hose; if you’re in front of it, you’re more likely to face a burst of liquid. Therefore, you should stay on one side while working.
- You should use the safer method first. For example, don’t use the loosening hose fitting method. Instead, use the control or built-in pressure relief valve if it is present. This method is safer than the first one. This will ensure minimal risk. If no other method works, then use the loosening hose fitting method.
- During pressure removal, ensure the hydraulic system is switched off (inactive). If it remains open, you won’t be able to release pressure. The third reason is that the hydraulic system will pump more fluid inside the hose, resulting in a pressure increase instead of a reduction.
- During pressure release, check for any weak point or crack on the hose. If you notice any crack, be very careful while removing the pressure. The chances of a hose burst can be very high in such cases.
- Last but not least, the hose contains hydraulic fluid. It can get fired if it makes contact with any flammable material. Therefore, your work area should not be cleaned.
Can I just turn off the machine to release hydraulic pressure?
The answer is NO! Turning off the hydraulic machine won’t release the complete pressure.
As you know, hydraulic machines use hydraulic fluid for their work. The liquid flows with very high pressure inside the hose, right? When you turn off the machine, fluid pumping stops. The fluid goes back into the reservoir. However, some fluid remains inside the hose and creates pressure. This pressure is called residual pressure.
Despite the machine being switched off, this fluid remains inside the hose. So, just turning off the machines doesn’t release all the pressure. Upon disconnecting the hose, this pressure can come out as a burst. Therefore, you will have to remove this pressure manually. The standard methods include using a pressure relief valve, adjusting the control valve, or losing the hose fitting.
Frequently Asked Questions
What happens if I don’t release the pressure before disconnecting a hydraulic hose?
This can result in lethal accidents as fluid will burst out. The pressure of this fluid is so extreme that it can cause skin burns. Therefore, you must release the pressure by disconnecting the hose.
How do I know if a hydraulic hose still has pressure in it?
If there is some pressure on it, the hose will be stiff. If you notice stiffness, the hose is filled with pressure, and vice versa. Moreover, some hydraulic systems come with pressure gauges. You can check the pressure on the indicator as well.
Can hydraulic fluid injure me if it sprays out under pressure?
Yes, hydraulic fluid spraying out under high pressure can cause injuries. If it is directed straight at your body, it can also cause skin burns. Therefore, I suggest staying on the side when removing the pressure to avoid an accident.
Conclusion
Hydraulic hoses are excellent tools for transmitting fluid. However, they should be managed carefully during maintenance and disconnection. Even if the machine is not working, some pressure can be inside the hose. This pressure can put stress on the hydraulic system and also cause hindrance during maintenance.
In this article, I’ve explained all the possible ways to help you remove the hydraulic hose pressure. Remember, these methods can be risky. So, you must wear the safety equipment before starting the process. However, the pressure removal process does not take much time. If you have basic know-how, you can remove complete pressure in a few minutes.