How Orientflex control the hose quality
useRubber hose widely serves in almost any industries. Thus the quality of rubber pipe is really important. However, during the production and usage, there will be various problem. Then next, let’s analyze these problems and find out the solution.
Uneven thickness of tube blanks
Cause analysis
Inconsistent plasticity of rubber or uneven heat refining; uneven feeding; mismatch between extrusion and pulling speed.
Solutions
Strictly control the plasticity of rubber and strengthen the heat refining process; feed evenly; match the extrusion and pulling speeds.
Crumbling of rubber layer
Cause analysis
Impurities in rubber; local self-sulfurization of rubber; rubber lumps or other hard particles mixed in rubber.
Solutions
Strengthen the cleaning of rubber; prevent self-sulfurization of rubber, improve the formula; strictly filter the rubber.
Blistering of rubber layer
Cause analysis
Water or low volatile matter in rubber; air is trapped during heat refining or feeding of rubber; extruder temperature is too high; insufficient screw thrust.
Solutions
Control the quality of raw materials; strictly control the heat refining process and feed evenly; control the extrusion temperature; regular inspection or replacement of the screw.
Uneven wall thickness
Cause analysis
Core mold offset; uneven rubber temperature.
Solutions
Cause calibration of core mold position; uniform heating of rubber and attention to heat preservation.
Tube adhesion
Cause analysis
Insufficient cooling; poor isolation effect; extruded tube billet squeezed too tightly.
Solutions
Sufficient cooling, pay attention to parking time; apply appropriate amount of isolation agent; extruded tube billet cannot be squeezed too tightly.
Quality defects and analysis and treatment methods of hose weaving or winding process
There are sundries on the surface of the outer rubber layer
Cause analysis
Impurities in the rubber layer; impurities in the isolation agent.
Solutions
Pay attention to environmental hygiene, filter the rubber when necessary; strengthen management to prevent impurities from mixing
Local bulges or depressions in the outer rubber layer
Cause analysis
Uneven outer diameter of the inner rubber layer; Not even rubber temperature when extruding the outer rubber; uneven speed and temperature fluctuations when extruding the outer rubber; uneven feeding.
Solution
Strictly control the extrusion size and molding quality of the tube blank; the rubber material should be fully heat-refined; timely check the screw speed and temperature control device; ensure continuous feeding.
The outer rubber layer is bubbling and delaminating
Cause analysis
The rubber material contains too much water; the braided and wound layers contain too much water or the glue is not dry; the outer rubber layer contains water and air is trapped during extrusion; the outer rubber layer or steel wire is contaminated.
Solution
Strictly control the moisture content of raw materials and rubber materials; fully dry the braided and wound layers and reduce the parking time; adjust the die shape and continuously supply glue; use solvent to clean its surface and strengthen environmental hygiene.
There are traces of placement on the outer rubber
Cause analysis
The plasticity of the outer rubber layer is too large; the parking time of the outer rubber layer after extrusion is too long.
Solution
Strictly control the plasticity; shorten the parking time after extrusion, and the room temperature should not be too high during parking.
The inner diameter is not round
Cause analysis
The plasticity of the inner rubber layer is too large; the tube core is deformed.
SolutionThe plasticity of the inner rubber layer should be low, and more attention should be paid to coreless molding; timely correction of the tube core diameter and timely replacement.
Quality defects of hoses in the vulcanization process and analysis and treatment methods
Lack of sulfur (surface blistering, deformation, frost spraying)
Cause analysis
Short vulcanization time; insufficient vulcanization vapor pressure; vulcanization speed of rubber material; condensed water in the tube core; too much condensed water in the vulcanization tank; too many hoses arranged in the tank, heat transfer is blocked.
Solution
Strictly control the vulcanization conditions; strictly control the vulcanization conditions; appropriately adjust the formula; the tube core is closed at both ends during vulcanization, or the iron core has a slight inclination; exhaust the cold steam regularly during vulcanization, and the condensed water should be exhausted before vulcanizing each tank; arrange the hoses according to the tank volume.
Blistering, delamination and sponge
Cause analysis
The temperature rises too slowly or the shaping is too slow during vulcanization; the raw materials and rubber contain too much water or the fabric contains water; the solvent has not evaporated completely; the semi-finished
product surface is stained with oil and foreign matter; the vulcanization pressure is insufficient; the cooling is insufficient when the water cloth is untied.
Solutions
The heating time should be shorter, and adjust the shaping point of the formula; strictly control the moisture of the raw materials, and dry it when necessary; dry more of the fabric; remoev foreign matter, oil stains, and focus on environmental hygiene; increase the pressure of the outer water cloth and rope; the water cloth should be unity after sufficient cooling after vulcanization.
The outer rubber layer has overlapping marks
Cause analysis
The temperature rises too quickly during vulcanization, and the rubber is shaped too quickly; the outer rubber layer has self-sulfurization.
Solutions
Appropriately slow down the heating time, appropriately adjust (slow down) the vulcanization speed of the outer rubber; remove and handle the self-sulfurized rubber, and improve the formula.
There are traces of placement after vulcanization
Cause analysis
The hose rack is not flat or has debris; too many hoses are arranged during vulcanization, and the bottom layer is under too much pressure; the pillow is too hard; the tube core is deformed; the vulcanization speed of the outer rubber layer is too slow.
Solutions
The rack should be flat and clean; appropriately reduce the number of vulcanized hoses; place pads; check the tube core in time; adjust the vulcanization speed of the outer rubber layer, and the vulcanization speed of the bare vulcanized hose should be appropriately accelerated.
Besides the production, there are many problems during use
Pipe burst
Depending on the location of the burst, pipeline bursts can be divided into two types. First, the bursting site is located on both sides of the hose, within 25mm of the bending sheath. The reason why this part bursts is that the rubber pipe is not manufactured or installed properly. For example, the rubber tube is stretched and distorted at the same time during the installation process. Or the bending radius of the rubber tube is lower than the minimum allowable bending radius. Second, the split distance between buttons is 25mm. This type of burst is due to excessive pressure in the hydraulic system or damage to the pipe body.
Oil leakage from pipe body
Oil leakage generally manifests as oil leakage or linear introduction after the vulcanized rubber bubble outside the hose. The sand holes on the pipe body are mainly caused by product quality problems of the hose. Such as residues in the glue in the pipe body, partial damage to the pipe body, defects in the pipe body during demoulding, etc.
Oil leakage at the interface
Oil leakage at the interface is mainly due to inconsistent specifications of the vulcanized rubber hose connector and the connecting connector connected to other components. Or it may be due to the mismatch between the rubber hose connector and the connecting connector. If the temperature-resistant hose fails, we should not panic. Let’s first analyze the existing problem. Is it a burst in the pipe body or an oil leak in some connecting areas? Understand the cause of the fault, or replace the connector or pipe with matching specifications. This will ensure that it will not affec subsequent production.
Precautions for use
1. Do not allow the high-pressure hose to twist during initial installation, otherwise the temperature-resistant hose will be damaged or the connector will become loose.
2. Install a high-pressure vulcanized rubber hose between the objects. Leave a certain amount of space to avoid friction between the high-pressure rubber hose and objects during operation. If not, try to get some safeguards. For example, use high-pressure hose protective sleeves.
3. During normal operation, do not drive the valve seat too quickly, but must be gentle. Otherwise, the high-pressure hose will burst.
4. In order to prevent damage to the high-pressure hose and restriction of water flow, the bending radius should be as large as possible.
5. When the hydraulic transmission system heats up too high during operation, the hydraulic oil pipe should be checked immediately. And adopt necessary refrigeration countermeasures during continuous operation.
6. When the bending radius of the temperature-resistant hose is too small. Use bevel connectors to prevent the hose from bending and bending significantly.
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