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عربىOTT RubberTech is a professional solution provider of rubber process formula, material, machinery with Mixer, Rubber Mixer, Mixing Mill, Precision Performer, Vulcanizing Press, Calender, batch-off Cooling unit, rubber Extruder, and other support plastic machines.
Features and Performance
The performance of an ozone tester is defined by its ability to maintain a precise, low-level concentration of ozone (typically 25 to 200 pphm) consistently across the entire chamber volume. Modern units use UV absorption sensors for real-time ozone monitoring and control.
| Technical Feature | Performance Standard |
|---|---|
| Ozone Range | 0 to 500 pphm (parts per hundred million) |
| Ozone Accuracy | Plus or minus 2 pphm |
| Temp Range | Ambient to 70 degrees Celsius |
| Sample Holder | Static or Dynamic (Stretching) fixtures |
| Air Flow | Laminar flow with adjustable velocity |
| Ozone Generation | High-voltage silent discharge or UV lamp |
Key features include a closed-loop ozone generator that automatically adjusts its output based on the sensor's feedback. Advanced models include "Dynamic Testing" racks that continuously stretch and relax the rubber samples during the test, which better simulates the real-world conditions of a moving tire or a vibrating gasket. The chamber is constructed from ozone-resistant materials like stainless steel and Teflon to prevent the machine itself from being degraded by the test gas.
Usage Tips and Techniques
The most critical factor in ozone testing is the "strain" applied to the sample. Rubber is generally resistant to ozone when it is in a relaxed state; cracking only occurs when the material is under tension. Samples should be stretched to a specific elongation (typically 20 percent) and allowed to "condition" for 24 hours before the ozone exposure begins to allow the anti-ozonants to migrate to the surface.
| Testing Focus | Optimization Technique |
|---|---|
| Sample Preparation | Ensure the edges are smooth to avoid stress risers |
| Pre-Conditioning | Store samples in an ozone-free dark area before the test |
| Air Velocity | Maintain a flow rate of 8-16 mm/s per ISO 1431 |
| Observation | Use a 7x magnification loupe for crack inspection |
| Safety | Ensure the ozone destroyer (charcoal filter) is active |
Operators should be careful not to touch the "test area" of the samples with bare hands, as skin oils can act as a temporary protective barrier and delay the onset of cracking. For high-accuracy research, using an "Automatic Crack Detection" system with a camera can remove the subjectivity of human observation, providing a precise "Time to First Crack" measurement. It is also important to maintain consistent humidity, as moisture can influence the rate of the chemical reaction between ozone and the polymer.
Maintenance Skills
Maintenance for ozone testers focuses on the ozone sensor and the generation system. Ozone sensors (especially UV-absorption types) can become "fogged" by rubber outgassing and require regular cleaning of the quartz windows. The ozone destroyer, which converts O3 back into oxygen before it is exhausted, must be checked regularly to ensure it is not saturated, as ozone is a hazardous gas.
| Maintenance Area | Procedure | Frequency |
|---|---|---|
| Ozone Sensor | Clean optical windows and check zero-point | Monthly |
| Ozone Generator | Check for high-voltage arcing and clean electrodes | Quarterly |
| Exhaust Filter | Replace activated charcoal or catalyst media | Annually |
| Door Gasket | Inspect for leaks (ozone has a distinct pungent smell) | Weekly |
| Calibration | Cross-check with a certified master ozone meter | Annually |
Maintenance staff must prioritize the safety systems. Because ozone is toxic even at low concentrations, any leak in the door seal or exhaust ducting must be repaired immediately. The airflow system should be checked to ensure that there are no "dead spots" in the chamber where ozone concentration might be lower than the setpoint. Regularly lubricating the dynamic stretching racks with ozone-resistant grease prevents mechanical wear and ensures smooth, consistent cycling.
Application Scenarios
Ozone testers are essential for any rubber product intended for outdoor or electrical use. They are primarily used by tire manufacturers, automotive weatherstrip suppliers, and producers of industrial hoses and power cables. They are also vital for the R&D labs of chemical suppliers developing new anti-ozonants and waxes.
| Industry | Typical Ozone Test Application |
|---|---|
| Automotive | EPDM door seals and window gaskets |
| Tire Industry | Sidewall compounds and rim-strip durability |
| Power & Energy | Testing the jackets of high-voltage transformers |
| Aerospace | Hydraulic hoses and external airframe seals |
| Marine Rubber | Mooring buoys and dock fenders |
In the automotive sector, parts must often pass a "no cracks at 72 hours" test at 50 pphm concentration. For tire manufacturers, the testing is much more rigorous, often involving weeks of dynamic cycling to ensure the tire sidewalls will not "brown" or crack over their 5-year service life. These chambers allow engineers to prove that their compounds can withstand the increasing levels of urban ozone pollution found in modern cities.
