Internal swaging system

Internal swaging system – general information

An internal swaging system was developed to provide permanent and safe fitting-hose connection. It ensures full and unrestricted flow through the fitting of a flexible hose assembly. The system utilizes a cold forming method – a mechanical method of fitting attachment. The key part of the system is a hardened, cone shaped swaging tool.

The diameter of the tool in its widest, working part is slightly bigger than the internal diameter of the fitting before crimping. The tool is pulled down the inside of the fitting so it expands to a desired diameter. The tail of the fitting compresses the hose against the ferrule. The internal swaging is opposite to traditional external crimping of ferrules as far as the process itself is concerned. The connection is achieved from the inside outwards, yet on the outside.

The main advantage of internal swaging over external crimping is the increase in a flow rate, because:

• when externally crimped, the hose tail of a fitting (inserted into the hose) reduces the flow diameter by the thickness of its wall;
• when internally swaged, the wall of the hose tail is entirely pushed into the hose. The inside flow diameters of both the hose and its fitting are the same Dw = Dk).

The bigger the flow rate, the shorter the reloading time – that makes the internal swaging method really cost-effective. Another advantage is the lack of obstacles and no turbulence at the tip of a hose tail which is crucial for the transfer of dry and loose or semi-fluid products (granules, grain, cement, concrete, etc.). The internal swaging system can be used for the majority of rubber industrial hoses from 2” (DN50) to 12” (DN300). It is particularly recommended for water and air hoses, fuels and other petrochemical products, delivery hoses for solids and for foodstuffs.

Fitting and ferrule selection

Internal swaging requires special fittings and ferrules (TM type). The ferrule is selected according to hose DN and its external diameter Dz (see picture below). Assemble in accordance with IT-86 manual. The maximum working pressure for internally swaged fittings is 20 bar. The maximum working pressure of the complete flexible hose assembly is also limited by the working pressure of connections (e.g. PN 16 flange) and by the working pressure of the hose.