Hydraulic hose assemblies

Hydraulic hose assembly

To say that rubber hose is an important part of a hydraulic system is a huge understatement. Hydraulics hoses have become progressively more complicated. Pressures keep getting higher while hose dimensions become smaller so they can be routed into increasingly tighter spaces. Suppliers offer hundreds of different types and styles of hydraulic hoses and thousands of different fittings to choose from. When it comes time to replace a hydraulic hose assembly, how do you know which hoses and fittings are the right ones?

Consider fluid temperature and ambient temperature

When determining which hose is right for your application, temperature is a critical factor.  There are two aspects of temperature to look at: ambient and media temperature.  Ambient temperature is the temperature outside of the hose, while media temperature is the temperature of the media being carried through the rubber hoses. The temperature rating of the hose should exceed the higher of the two temperatures of the application. Also consider the media type when selecting a hose. Some media types can increase or decrease the effects of temperature

Does your application require a tight bend radius

The minimum bend radius of a hydraulic hose refers to the minimum radius that the hose may be bent through while operating at the maximum allowable published working pressure. Bending radius provides enhanced flexibility and eases routing. However, bending the hose below the minimum bending radius leads to loss of mechanical strength and hence possible hose failure. A minimum straight length of 1.5 times the hose’s outside diameter (OD) shall be allowed between the hose fitting and the point at which the bend starts.

Do not ignore maximum pressure ratings

When considering industrial hose pressure, be sure to consider the system working pressure as well as any surge or spike pressures. These pressures should be below the rated maximum working pressure of the hose. It is important to note, when considering hydraulic hose assembly pressure, the maximum working pressure of the system is the lowest rated piece of the assembly. Hose pressures can be found on the engineering specifications for each hose as well as our hose overview chart.

Fitting selection can be complicated

The fitting-to-hose mechanical interface must be compatible with the industrial hoses selected. The proper mating thread end must be chosen so that connection of the mating components will result in leak-free sealing. 

Another component of fitting selection is thread type.  For hydraulic hose fittings, there are several different types of thread types: German DIN hose fittings；British Standard Pipe (BSP)；French Gas fittings；Japanese fittings. There are proper assembly procedures for each of the fitting styles, and strict adherence to those steps makes the difference between a solid connection and a problem waiting to happen. To assure the correct identification, the threads must be measured and compared to the tables listed here.