Detailed resistance lists on cleaning materials, service lives and temperatures ensure that the hoses are not damaged by this. Stephan Renz reports
Hoses are used as flexible transport connections wherever foodstuffs are handled and processed.
Directive (EC) No. 1935/2004, known as the framework regulation, and Directive EC 2023/2006 on good manufacturing practice, apply to hoses and machines or storage and transport containers that come into contact with foodstuffs.
According to these, materials and objects should be used that do not allow any, where possible, or only very low levels of, materials to flow into the foodstuffs and do not change the olfactory characteristics of the foodstuffs. In addition, commodities – like hoses – used to transport foodstuffs must be properly cleaned and, in certain cases, disinfected, in accordance with the current law on foodstuffs.
In order to avoid damage to the hose material, the user should request written documentation on resistance to cleaning agents and disinfectants from the hose provider or supplier.
These documents should not only provide information about basic cleaning agents and various combination products, but also statements regarding the maximum duration of exposure, application temperatures and concentrations. This increases production reliability accordingly.
Owing to the diversity and ongoing changes in the composition of the various agents, it is impossible to provide exhaustive documents containing all cleaning substances.
However, ContiTech can supply appropriate information on request. And where necessary, the manufacturer of the cleaning agent can be consulted to determine the parameters required.
Extruded, not wrapped
To avoid contaminating the goods being conveyed in the long term, the inner lining should not be wrapped but should be extruded instead, as in ContiTech food and beverage hoses.
A wound liner could come apart at its winding seams after being subjected to mechanical effects or excessive heat, and thus turn into a food safety weakness.
Depending on the quality of the wrapping, gaps may appear in the inner lining, which cannot always be flawlessly cleaned and therefore carry a risk of products mixing and contamination.
Hoses made of rubber or plastic-rubber composites are subject to natural ageing. This can be accelerated by mechanical and thermal influences. In order to identify and eliminate possible risk factors in good time, the condition of the hoses must be checked regularly.
One of the tests that should be carried out as part of the regular inspection is a pressure test with water. This test is run for five minutes at 1.5 times the permissible operating pressure.
In addition, the hose should be checked visually for dried leaks in the area of the fittings as well as for creases in the hose cover from bending. It should also be inspected for cracks and blisters. The safest way to monitor hose lines is with an identification and documentation system, as is normal in the chemical industry. They should also be clearly labeled with identification numbers, which are in turn documented.
Stephan Renz is a Technical Consultant for industrial hose solutions at ContiTech.