Saturday, Oct 21, 2017

Industrial Rubber Hoses; Uses and Production

This video from the Discovery Channel explains the usage and how industrial rubber hoses are made.

Rubber hoses find a variety of applications in domestic as well as industrial sector. Some rubber hoses are used for supplying air, water or raw materials to different machines; others may be used for removal of water or liquid wastes, whereas some may be used to feed ingredients to a mixer in a food production unit. Depending upon the purpose for which the hose is used, the composition as well as the color of the material varies.

This company mainly specialises in the production of low pressure and medium pressure rubber hoses. A wide range of industrial rubber hose in different outside diameters and different pore sizes and varying degrees of flexibility are manufactured. Some hoses have specialty features such as heat resistant fabrics incorporated right into the rubber layers.

The process of manufacture of these rubber hoses is quite interesting. In the beginning, the raw material arrives at the factory in the form of rough strips, which is run through a mill. The rough strips are heated in a roller which softens the rubber, and smoothens into an even texture. Depending upon the size of rubber hose that is being constructed, the rubber is cut in strips as per the required width and thickness.

The rubber strip is wrapped around a rotating steel mandrel, which is of the same size as that of the hose bore. Before wrapping of the strip, the mandrel is properly lubricated so that it is easier to remove the rubber hose from the mandrel later on. To achieve the required thickness, layering of the rubber strip is sometimes done.

The second layer is the reinforcement layer which is a rubber coated high strength synthetic fabric designed to withstand the operating pressure to which the rubber hose will be subjected.

The final layer of the rubber hose is the outside covering. After measuring the thickness and required diameter, the entire hose assembly is wrapped tightly in wet nylon tape, which will later shrink and compress all the materials together.

This factory also manufactures hoses with a built-in attachment on the ends. The built it attachment is positioned on the mandrel and glued to the first layer of rubber strip. It is further reinforced with special textile strips. High strength carbon steel wire is tightly wound over the attachment and wound loosely down the body of the hose at a specific angle which is designed to withstand vacuum pressure. To fill the gaps between the layers, the hose is then wrapped in a soft stretchy rubber strap. Subsequently the high-strength rubber coated fabric and the exterior covering is wrapped. Finally the hose is pressure wrapped with wet nylon tape. For making the hose more flexible, corrugations are created in the body of the hose. A rope is wrapped tightly around the hose, which creates a dip under compaction. A second layer of nylon tape is wrapped to further hold the rope in place.

After construction, the finished hose is fed into an autoclave along with the mandrel. An autoclave is a cylindrical chamber into which hot steam is injected at high pressure. This process of vulcanization triggers a chemical reaction that makes the rubber elastic. Subsequent to this process, the mandrel is taken out from the autoclave, cooled and the shrunk tape is removed from the hose. The nylon tape is then washed and later reused.

The next process is to remove the hose from the mandrel. One end of the hose is tied with a rope and water is gently pumped between the rubber hose and the mandrel. The lubricant, which was applied earlier, prevents the mandrel from sticking to the rubber hose, and the rubber hose slides easily over the mandrel and gets separated.

The ends of the hose is then trimmed off and cut to the required length as ordered by the customer. The finished hose is now packed and ready.


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