Tips for Selecting and Maintaining Rubber Hoses

Hydraulic hose assembly = hydraulic hose + hydraulic fittings + crimping operation + quality control

In the field of fluid power transmission: hydraulic hose assemblies are high-performance products, and therefore must be handled with great care to extend their service life and ensure that any issues are detected at the earliest possible stage. Since these assemblies are required to withstand high pressures and form part of complex systems, various hazards can arise when handling them, so extra caution is essential.

For products manufactured by FDC, even the most durable hydraulic hose assemblies used in construction machinery, transportation equipment, and processing equipment have a limited service life. To make the most of these products, it’s essential to select the correct type and specifications.

If the wrong choice is made, the service life of the hose will be significantly shortened. Wherever there’s a hose, there must be a matching connector to connect the hose and enable it to function. The selection process we commonly follow is:

1. Select the correct hydraulic hose;

2. Select the correct fittings to match the hydraulic hose;

3. Use the correct crimping operation;

4. Features a traceable quality control process.

Faced with a wide variety of fittings and hoses, how should we choose the right connectors to match our hydraulic hoses and ensure they’re suitable for our machinery?

The following are some common mistakes in selection and use:

1. Bending the hose below the minimum bending radius.

2. Twist, kink, pull, or wear the hose.

3. Operate the hydraulic system below the minimum temperature or above the maximum temperature.

4. Expose the hose to pressure fluctuations exceeding the maximum recommended working pressure.

5. Mixing hoses, incorrect assembly of equipment, or mismatching of accessories according to the manufacturer’s instructions.

When selecting hydraulic hoses for any industrial application, consider the required size and performance specifications.

The products we at FDC manufacture provide customers with “worry-free,” “one-stop” product services.

It is worth noting that the rated pressure of the fittings must match that of the hose and the rest of the system. If it is lower, the maximum pressure of the entire system will be reduced.

If you overlook this point, you could end up having the accessory come loose (detached) under pressure.

When selecting the right accessories, be sure to match them properly with the hose. You need these two components to work together; otherwise, both could be damaged.

The selection of hydraulic hoses requires consideration of the following three aspects:

Size specifications:

The dimensions that need to be considered for hydraulic hoses are the inner diameter and the outer diameter. The minimum bending radius is a combination of these two factors: first, the acceptable deformation of the hose’s cross-section; and second, the mechanical bending limit of the reinforcement layer.

Performance specifications:

You need to consider the type of fluid being conveyed, as well as the fluid’s concentration and any substances or chemicals in the fluid that could erode the hose.

The hose you select must be able to withstand any special oils or chemicals that might pass through it. The same applies to the working environment in which the hose will be used. For example, ozone, ultraviolet radiation, chemicals, saltwater, and pollutants can all degrade the hose, leading to premature aging.

There are tens of thousands of reasons for hydraulic hose failure, but with appropriate preventive measures, the most common failures can be avoided.

1. Fluid compatibility

Incompatible fluids can cause the inner rubber layer of the hose assembly to degrade, swell, and delaminate. In some cases, the inner rubber layer may even be partially damaged. The hose must be compatible with the fluid being conveyed. It is essential to ensure that the fluid is compatible not only with the inner rubber layer but also with the outer rubber layer, fittings, and even O-rings.

2. Dry air/ stale air

The inner rubber layer of the hose may develop numerous tiny cracks due to aging or dry air. Sometimes, this type of failure is difficult to detect because the hose can still remain flexible, yet signs of external leakage may appear.

To avoid issues related to dry or stale air, you should ensure that your hose rating is suitable for extremely dry air conditions. For such applications, it’s best to choose hoses made with PKR or EPDM inner-rubber materials.

3. Minimum bending radius

If the minimum bending radius is not met, the hose assembly may fail relatively quickly.

In vacuum or suction applications, if the bending radius is exceeded, the hose may flatten in the bent area. This can impede or restrict the flow of the medium. If the bend is too severe, the hose may become kinked. To prevent hose failure due to exceeding the minimum bending radius, the recommended bending radius should be carefully checked.

4. Wear and tear

Hydraulic hoses are subjected to harsh environmental conditions every day, and the resulting effects will eventually become apparent on the hoses themselves. If inspections are not carried out regularly, wear and tear could lead to hose assembly rupture and leakage. If a hose experiences excessive friction against external objects or even another hose, it can erode the hose’s coating and eventually wear down the reinforcing layer.

A properly assembled and installed hose will have a longer service life, thereby reducing downtime and maintenance costs.