Non-metallic or rubber hoses are divided into two main categories:

1. Hydraulic Hoses: Used for fluid transfer, typically hydraulic oil, in a closed circuit.
2. Industrial Hoses: Used for transferring various fluids (water, acid, base, petroleum derivatives, etc.)

These hoses are composed of three layers:

Inner Tube: Provides chemical resistance to the fluid passing through the hose.

Reinforcement Layer: Usually consists of 1 to 2 layers of fabric (cord) or 1 to 6 layers of wire woven over the inner tube. This layer withstands the internal pressure of the hose.

Cover: The outer layer of the hose, used for protection against external factors. It also serves as the hose’s identification, allowing for the recognition of the hose’s specifications.

Basic Concepts:

Working Pressure: The pressure range for which the hose is designed to operate. The commonly used unit is “bar.”

Burst Pressure: The minimum pressure at which a hose bursts. This is determined by testing several samples of the same hose and noting the lowest burst pressure.

Nominal Diameter: The internal diameter of the hose, used for sizing. Hose sizes are usually expressed in inches.

Minimum Bending Radius: The smallest radius at which the hose can be bent. The “bending radius” is a critical factor in selecting a hose. As the hose bends, the inner tube and cover stretch and thin out, significantly reducing the hose’s pressure resistance.

Weight per Unit Length: Refers to the weight of the hose per meter. It is usually expressed in “kilograms per meter.”

Hydraulic hoses are typically manufactured up to 3 inches in size and can withstand pressures up to 700 bar. Industrial hoses are generally produced up to 12 inches in size, with a maximum pressure tolerance of 40 bar.