The auto darkening welding helmet is an automatic protective helmet made of principles such as optoelectronics, motors, and photomagnetism. Germany first promulgated the DZN4647T.7 electronically controlled welded window cover and glasses standard in October 1982, and the BS679 standard promulgated by the United Kingdom in 1989 stipulates the time when the light shield changes from the light state to the dark state during welding. China began to develop photoelectric automatic color-changing welding protective helmet in the early 1990s.
First, the structure is composed of two parts: the main body of the helmet and the light changing system. The main body of the helmet is head-mounted, with flame retardant ABS injection molding, lightweight, durable, can be adjusted from three different parts, can adapt to a variety of head shapes. The light system includes a light sensor, control circuitry, liquid crystal light valve, and filter.
Second, the principle of protection ,The strong arc radiation generated during welding is sampled by the light sensor, triggering the control circuit, and the output working voltage of the control circuit is added to the liquid crystal light valve, and the liquid crystal light valve changes from a transparent state to an opaque state under the action of the electric field, and the ultraviolet transmittance is very low. Part of the infrared light through the liquid crystal light valve is absorbed by another filter. Once the arc light is extinguished, the light sensor no longer emits a signal, the control circuit no longer outputs the operating voltage, and the liquid crystal light valve returns to a transparent state.
Third, the main technical requirements :1. size: the effective observation size shall not be less than 90mm×40mm. 2. Photogen performance: shading number, ultraviolet/ infrared transmission ratio, parallelism should be in line with the provisions of GB3690.1-83. 3. Strength performance: The observation window should be impacted three times without any damage at room temperature with 45 grams of steel balls falling freely from a height of 0.6m. 4. The response time shall comply with the relevant regulations.
Fourth, Precautions for use: 1.Auto darkening welding helmet is suitable for all welding work sites, there are handheld and head-mounted two products. 2. When the goggles appear to flash or darken when in the bright state, the battery should be replaced. 3. Prevent heavy falls and heavy pressure, prevent hard objects from rubbing the lenses and helmet.