What are the requirements of the rigid PVC spiral reinforced PVC hose

February 28, 2018

Rigid PVC spiral reinforced PVC hose is a hard PVC round a spirally wound composite reinforced pipe in soft, PVC tube forming, its structure as shown in figure.

 

In the above picture, 1 are hard PVC spiral strips and 2 are soft PVC tube walls

The stiffness and working strength of the soft PVC tube are improved because of the rigid PVC circular spiral as the skeleton in the PVC hose. In this way, spiral PVC tube can transport the liquid with certain pressure, the tube has the advantages of corrosion resistance, easy to bend. In some areas, it can replace liquid or gas and granular solids instead of rubber pipes or steel pipes. It can also replace metal hoses as cable sheath for electromechanical equipment.

 

 

The raw materials and formulation

The reference formula of the rigid PVC spiral strip forming material in the rigid PVC spiral reinforced soft PVC tube is as follows:

PVC 100, calcium and zinc stabilizer 3.8, light calcium carbonate 10, paraffin 0.5, stearic acid 0.6, CPE 5, ACR 1, titanium dioxide 1.5

And soft PVC tube molding formula:

PVC 100, barium chromium zinc liquid stabilizer 1.2-1.5, DOP 60, epoxy soybean oil 5, stearic acid 0.3, 70S 0.25

 

 

The molding equipment

Extrusion molding PVC hose rigid PVC spiral, because products are PVC products molding compound, with two kinds of different performance of production, raw materials of different formula of the two kinds of products in two mixer mixing, and then in two extruders in plasticized melt.  The molten material into the extrusion molding of rigid PVC spiral respectively from the two entrance mould enhanced PVC hose in mold, composite pipe forming. Two extruding machine specification, because the molding composite pipe of soft PVC material than the hard PVC material material, so the selection of extruded soft PVC feed extruder specifications should be greater than PVC extrusion hard material extrusion machine specifications. The structural form of the screw in the extruder is exactly the same as the structure of the screw for the extruded PVC products.

 

In the above picture, A is a soft PVC imported B is the import of hard PVC melt.

 

See from the enhanced mold soft PVC tube can be, this composite mould structure and ordinary rigid PVC pipe forming mould structure is basically the same, the difference is more than a rotating die. Melt soft PVC pipe extrusion, in the composite mold tube, by extrusion of rigid PVC melt and the other a molding of rigid PVC spiral strip, from the die side turning into soft PVC tube, because the die hard PVC rotation, wrapped in soft PVC tube on the circumference of the tube, with the mobile move, because the soft PVC has a larger flow of molten material by pressure molding mold, in moving, no exit before the model of soft PVC melt the rigid PVC spiral fully inclusive, forming complete rigid PVC spiral soft PVC tube billet by extrusion die, forming spiral tube.

 

The molding process

Raw materials used in two kinds of rigid PVC spiral reinforced hose of PVC products mixing, mixing respectively in two sets of high speed mixing machine, the same operation method and raw material mixing process of temperature and ordinary hard soft PVC products of raw materials mixing process temperature and method of operation.

 

Two extruders respectively extruded two kinds of products. The plasticizing temperature and the molding temperature in raw materials of the two products were the same as that of extruder extruding ordinary rigid and soft PVC products. The production can be adjusted according to the temperature conditions of the common PVC hard and hose forming process.

 

The PVC hose extrusion note rigid PVC spiral

PVC hose composite forming by extrusion melt of hard and soft materials to two kinds of PVC products, and the quantity of materials to enhance the forming of rigid PVC spiral. For extruding rigid PVC strip, the speed of extruder screw should be extruded, and the flow rate of extruded soft PVC material can be extruded, and the corresponding rigid PVC bar shall be extruded, and the flow rate of soft PVC tube will be coordinated.

The die with a rotating commutator motor (or DC motor), through the deceleration gear box driven by a chain drive, rotating speed adjustable die. When adjusting the speed of the die, it should be adjusted according to the winding pitch size of the hard PVC bar. When working, the rotating speed of the die should be stable.

The inner circle surface of the rotating die has a semicircular spiral groove, which is used to shape the outer spiral of the reinforced tube. The depth of this semicircle spiral groove should be determined by the thickness of the tube and the diameter of the hard PVC spiral strip. It is necessary to ensure that the soft PVC melt can fully contain the external spiral materials of the hard PVC strip and the forming tube.

The attention of rotary die within each working round the surface finish and concentric with the core shaft accuracy requirements, two parts molding with the surface roughness of Ra should be less than 0.25um. The die work long time rotation, pay attention to the sealing parts of the two movement here, the application of wear resistant and high temperature resistant, sealing gasket (such as graphite or PTFE gasket), to prevent the melting and extruding, affecting production.

 

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