How To Use A Hydraulic Hose Testing Machine?
How To Use A Hydraulic Hose Testing Machine?
Hydraulic Hose Test Standard
Why are there different standards for hydraulic hoses and what do these standards mean for your application? SAE J517 has set the basic standards for hydraulic hoses from 100R1 to 100R12 for decades. These SAE standards, which are manufacturer-oriented, determined the technical requirements (pressure resistance, etc.) that hydraulic hoses must meet by classifying them according to their internal structure. SAE standards set minimum levels of pressure resistance for hoses, which vary according to the bore size. This classification was later revised to describe hoses with "compressive strength not changing by size" as a group, such as R13, R15, R17 and R19.
But recently, hydraulic system designers have begun to adopt ISO specifications. Many major OEMs have passed ISO standards in their design and manufacturing processes to secure the sale and service of their equipment to many different locations around the world.
The ISO 18752 Standard, published in 2006, takes a different approach that focuses on the design practices of users who often design hydraulic systems according to performance and pressure requirements. The ISO 18752 Standard examines hydraulic hoses in nine pressure classes with a maximum working pressure of 500 to 8,000 psi. In addition, hydraulic hoses that meet ISO 18752 specifications are divided into four different classes according to their "impact resistance": A, B, C and D. Each class has a certain number of pulsed working life (cycles) specified in the standard at a certain temperature and pulsed working pressure to meet the relevant standard. ) must complete successfully. In addition, hoses are classified as standard types (AS, BS, CS) or compact types (AC, BC, CC, DC) according to the outer diameter of the hose. Compact types have a much smaller outer diameter and bending radius than standard types.
Hydraulic Hose Static Pressure Test
SAE and ISO Specifications for Hydraulic Hoses - Hose Strength Test - Hose Division
The main concept in the ISO 18752 standard is that the corresponding pressure level remains the same for different hose sizes. This specification also requires that a spiral-braided hose manufactured according to ISO 18752 impact resistance class D, type DC, exceeds one million pulse duty cycles of pressure. This is the highest endurance value among those that must be achieved for all classes given in the standard and requires at least one million pulse cycles to be met with fluid at 248 ° F (120 ° C) and in pulsed operation at 1.33 times the maximum working pressure. In this accelerated test, the hose is placed in a U-shape on a test stand and the fluid is raised to the specified working pressure. Pulsed pressure is applied to the spiral braid layer and hose couplings in such a way that a working cycle at the required minimum number of pulsed pressure is achieved.
Benefits of ISO for End Customers and Engineers
The ISO 18752 standard makes it easy for end users and engineers to determine which hose to use on a particular equipment or machine tool. Strict testing requirements allow users to know exactly what the hose is designed for and how it should perform on hydraulic equipment. Many users are switching to ISO standards, as hoses tested to higher impact standards will likely have a longer hose life. For example, if you need hydraulic hose for a demanding application that will be subjected to multiple pulsed pressure cycles in a short time and will provide a long continuous service life, you would choose assembled hoses with impact class C or D. However, this assumption also depends on the correct attachment (assembly) of the hose assembly and protection from harsh environments.
An important aspect of ISO standards is their worldwide acceptance. So you know that no matter where your hose was manufactured or purchased, it has been tested to the same standards. Global manufacturing standards are essential to many original equipment manufacturers (OEMs).