Self-floating mud drainage hose is composed of inner rubber layer, reinforced skeleton layer, middle rubber layer, floating material layer, rubber protection layer, and steel flange joint. Its length is generally 11.8 meters, and its inner diameter is between 600 and 1000 mm. Compared with the ordinary rubber hose, the difference is three: First, its shape size is large, and its length is about 6 times of the general rubber hose. Due to the increased size of the shape, its molding is difficult and the processing capacity of the equipment is required to be high. Second, the structure of the floating material layer, with its own floating performance. Due to the structural changes, many adjustments have to be made in the molding process. Third, high pressure and wear resistance requirements, in the structure design to make appropriate adjustments.
The self-floating mud discharge hose has good self-floating performance, good flexural performance, and excellent impact resistance. The use of this product will make it possible for the dredger to carry out construction in windy and rough waters and windy seasons, realizing all-weather construction. In addition, the self-floating mud discharge hose has the advantages of easy assembly and long service life, which improves dredging efficiency and reduces dredging costs. It will become an alternative product to the traditional water dredging pipeline.
The forming process of self-floating mud drainage hose can be divided into three parts: firstly, tube body forming; secondly, floating material winding forming; thirdly, rubber composite outer protection layer forming.
(1) Tube body forming
The main difference is that the length is increased, which is about 6 times the common hose. The main technical difficulty is that due to the increase of the length of the tube body, the heat shrinkage of the cord fabric layer as the skeleton material also increases, which easily causes the rubber to shrink and turn out at the flange short tube at both ends of the hose; in the test, the way of wrapping multiple layers of cord fabric strips around the end of the tube was adopted to solve the phenomenon of rubber turning out and improve the appearance quality of the hose.
(2) Floating layer forming
The technical difficulty of floating layer molding is how to solve the problem of overall molding between floating material and tube body and between floating material layers. This project adopts an adhesive forming process, and the adhesive is 309 adhesive. The bonding strength of 309 adhesives is greater than the strength of polyethylene floating material itself, and it has a certain flexibility, which is suitable for use on a self-floating mud discharge hose. At the same time to facilitate the realization of the process requirements of ring wrap forming, as well as to facilitate the application of sufficient pressure on the polyethylene foam sheet to meet the requirements of the bonding process, the traditional specifications of 100 mm thick polyethylene foam sheet processed into 50 mm thick, so that the polyethylene foam sheet and the pipe body can be more closely combined. The test proves that the floating layer formed by taking the above measures can still maintain good integrity after repeated flexing, without loosening, deformation, and misalignment.
(3) Rubber composite protective layer molding
The biggest technical difficulty of rubber composite protective layer molding is the heat and pressure deformation of the floating material in the secondary vulcanization process. As the vulcanization temperature of rubber is generally above 140℃, the floating material will shrink and deform when the temperature exceeds 120℃, thus reducing the floating ability and seriously affecting the appearance quality of the self-floating hose. For this reason, the researchers made two improvements to the production process: one is to prepare low-temperature vulcanized rubber and reduce the vulcanization temperature. The second is to apply a uniform preload to the floating material to improve its compressive performance. The test proved that after taking these two key measures, the trial self-floating mud discharge hose solved the problem of vulcanizing the rubber compound protective layer well and also improved the surface flatness of the self-floating hose.
Through continuous experiments and summaries, and combined with years of experience in processing hoses and floating bodies.
Initially, we have formed the operating procedures for self-floating mud discharge hose, formulated the enterprise standard for self-floating mud discharge rubber hose, and filed it in Dezhou Quality and Technical Supervision Bureau. The standard is used as the basis for production, inspection, and acceptance.
The main technical requirements of the self-floating mud discharge rubber hose are:
(1) The quality index of the tube body meets the requirements of HG/T2490-93.
(2) Water absorption rate of internal floating material ≤ 1g/100cm2.
(3) The appearance quality meets the standard HG/T2185 standard requirements.
(4) The tube body is 1.5 times the required working pressure under the fixed pressure test, no leakage, local bulging, and other abnormal phenomena.
(5) between the floating materials, floating materials, and rubber bonding peel strength ≥ 40N/cm.
