Recently, a primary school in Panyu was mistakenly turned on by the teacher as a light disinfection lamp, which caused the students in the two classes to have multiple discomforts such as eyes and skin, which caused many parents to pay attention. UV disinfection lamps are currently widely used in public places such as hospitals and schools, and accidental opening incidents are frequently reported. Then, what kind of harm will the UV disinfection lamp used for sterilization cause to the human body? Will it be a serious sequelae caused by parents' fears?
Case: Teacher mistakenly turned on UV disinfection lamp
According to reports, on September 9th, when a primary school in Panyu was in a computer class, the teacher mistakenly used the UV disinfection lamp as an illumination lamp for nearly an hour. Many children were experiencing discomfort. Some parents described that their children got up at one o'clock in the morning. "The tears of the eyes are gone, the eyes can't be closed at all... The next day, the eyes are red and swollen. You need to take four times of anesthetic to go to the hospital to check. ". Some parents said that their children's face, neck and other exposed parts are too red. "The whole body can't be licked, and it hurts when you touch it." One week after the incident, parents still said that the child’s eyes were stinging with light, his face began to peel, and his bare skin was like “white hurricaneâ€.
Looking at the information, it is not uncommon to accidentally open the UV disinfection lamp in recent years.
In July 2013, the Beijing Morning Post reported that a private training school in Shijiazhuang, Hebei Province, used ultraviolet disinfection lamps as lighting lights. Some students were exposed to ultraviolet radiation for up to 4 hours. Some children developed redness and pain in the eyes and blackened skin. Other symptoms, such as vision loss, fever, hair loss and other issues.
In May 2016, a primary school in Luohu District, Shenzhen was tripped due to a line. After the electricity was restored, the teacher accidentally turned on the UV disinfection lamp, causing many students to have eye discomfort.
Many parents worry that children who are mistakenly photographed by UV disinfection lamps will have permanent damage to their vision, whether the skin will leave scars, or even the risk of skin cancer, blood cancer and cataract.
In an interview, the reporter found that in hospitals where ultraviolet disinfection lamps were frequently used, accidental opening incidents occasionally occurred. Patients who had hospitals were exposed to ultraviolet light and became "black people." How much damage is caused by UV disinfection lamps, and even some doctors have no heart in mind. In the fruit shell network, there are netizens who consult their own doctors as dentists, because the hospital disinfects with ultraviolet rays every night, and is very afraid of ultraviolet light. "Worried about radiation."
Different wavelengths of ultraviolet rays hurt people
Professor Wen Ju, director of the Department of Dermatology, Second People's Hospital of Guangdong Province, introduced that ultraviolet light is an electromagnetic wave with a wavelength of 100-400 nm. According to the wavelength and biological effects, it is mainly divided into three bands, long-wave UVA, medium-wave UVB and short-wave UVC. Ultraviolet rays account for about 13% of sunlight, UVA accounts for about 97% in nature, and UVB accounts for only 3%. The ultraviolet rays used for sterilization are mainly short-wave ultraviolet UVC. In general, the shorter the wavelength of ultraviolet light, the stronger the lethality.
Professor Wen Ju introduced that UV disinfection lamps are mainly used for air disinfection. At present, indoor air disinfection in most hospitals in China is carried out by using ultraviolet disinfection lamps and ultraviolet sterilizers. This method is simple and easy. The inner surface of the ultraviolet lamp emits a wavelength range of 200-270 nm, and the center wavelength of the sterilization is 253.7 nm, which is a short-wave ultraviolet ray. This type of ultraviolet light is mainly caused by radiation damage to microorganisms (bacteria, viruses, spores and other pathogens) and the function of destroying nucleic acids to kill microorganisms, thereby achieving the purpose of disinfection.
Exposure to ultraviolet light for a long period of time can lead to skin pigmentation, rough skin roughness, photoaging, and serious precancerous lesions, skin cancer, cataracts, etc., so long-term UV exposure should be avoided. However, the short-term exposure to UV disinfection lamps is mainly caused by electro-optic ophthalmia and skin damage, and other cancer-causing risks are minimal. "The sterilized UV lamp is a short-wave UVC with very low penetration, mainly causing the most damage to the skin surface. How much damage the UV disinfection lamp causes to the human body depends on the power and duration of the exposure."
For parents who have stated that the child has taken ultraviolet disinfection lamps, the skin peels like "white hurricane". Professor Wen Ju said that the damage caused by ultraviolet rays to the skin is related to the tolerance of the individual's skin. In a similar case, the duration of exposure for one hour is similar to that of solar dermatitis, mainly because the skin becomes red, black, and dry, and the patient may have pain, molt, and even blisters. This is an allergic reaction to the skin's UV rays. Patients can go to the dermatology department for anti-allergic and skin care treatments. The general "sunburn" will heal in about 1-2 weeks. From clinical experience, there are no skin ulcers, breakages, infections, etc., and no scars are left. Pigmentation will slowly improve as the skin recovers. Professor Wen Ju reminded that during the rehabilitation period, patients should pay attention to avoid sun exposure, reduce the time of computer, TV, mobile phone and other screen radiation, and keep the diet light, which is good for the recovery of the disease. "Skins, such as skin and hair, which are generally slightly burned by ultraviolet rays, can be cured quickly, and there is basically no sequelae."
Rubbing your eyes will increase your trauma and delay your recovery
Another hazard of short-term exposure to UV disinfection lamps is electro-optic ophthalmia. Mainly manifested as red eyes, tears, dryness, photophobia, and serious even lead to decreased vision. Li Yanying, deputy director of the Department of Ophthalmology, Second People's Hospital of Guangdong Province, said that usually 30-60 minutes of ultraviolet radiation can cause electro-optic ophthalmia, which is caused by a large amount of strong ultraviolet rays absorbed by the corneal epithelial cells and conjunctiva. The corneal epithelium of the patient will be Diffuse punctate waves appear, usually manifested as red eyes, especially afraid of light, can not help crying, the most unbearable is that people will feel severe pain in the eyes. Li Yanying said that the electro-optic ophthalmia caused by ultraviolet radiation usually has an incubation period, which is half an hour later, and only 6-8 hours after the slow attack. Therefore, the hospital emergency department often receives such patients in the middle of the night to seek medical treatment.
However, Li Yanying said that the short-term UV disinfection lamp irradiation, the damage to the cornea is relatively superficial, mainly in the epithelial layer, usually 24-48 hours to repair itself. For patients who are painful and intolerable, doctors usually use chloramphenicol to add a little anesthetic eye drops to achieve analgesic and anti-inflammatory effects. However, there are more delays in corneal repair, so it is not very painful. It is best not to use this type of anesthetic. During the rehabilitation period, patients should pay more attention to rest, avoid using eyes, and pay attention to eye hygiene. "In particular, don't rub your eyes, otherwise it will cause the corneal epithelium to fall off and the recovery time will be prolonged."
Whether the child's vision will be permanently damaged is the most concerned issue for parents. In this regard, Dr. Li Yanying said that the UV disinfection lamp was exposed for a short period of time, which would damage the vision. However, after the corneal repair was completed, the vision could be restored. Parents should not worry too much about the sequelae.
These ultraviolet rays can cause damage
Short-term exposure of indoor UV disinfection lamps generally does not damage the parenchyma and crystals of the cornea, but if the outdoor ultraviolet rays are exposed for a long period of time, the damage to the eyes is permanent. Li Yanying pointed out that long-term activities in areas with strong reflections in snow, desert and water surface can cause skin cancer, eye lymphocyte cancer, cataract, retinopathy, macular damage, and pterygium in the eye if there is no protective measure. There is a variety of problems between the growth of a membrane, the degeneration of the conjunctiva, and the loss of vision in the cornea. Therefore, people who work outdoors for a long time, it is best to wear a sunglasses to protect against UV rays.
In addition, looking at the eclipse with naked eyes is also an act that can easily cause eye damage. There was once a male patient in his 20s who saw the solar eclipse without any protection. After that, there was a fixed black shadow in front of him, and the deformation of his eyes was noticeable. After a period of treatment, although the black shadow fades and the deformation disappears, the nerve cell damage caused by the macular area cannot be completely repaired.
Some people have raised doubts that misdiagnosis of UV disinfection lamps will cause certain harm to the human body. So is the ultraviolet mosquito killer lamp currently used for home or outdoor damage to the human body? In this regard, the research and development personnel of the mosquito lamp company said that it has the ability to kill bacteria. Unlike the strong medical disinfection lamps, the UV wavelength emitted by the mosquito killer is UVA, which is not harmful to the human body. However, if it is exposed for a long time, it will cause sunburn, burns, dry eyes, etc., so do not put the household mosquito lamp on the bed.
Although ultraviolet light may cause the above-mentioned harm to the human body, the public does not need to talk about ultraviolet color change. Professor Wen Ju introduced that in addition to sterilization and disinfection, ultraviolet light also has certain physiological effects. It is an indispensable factor for the synthesis of vitamin D and the absorption of calcium. Ultraviolet rays are also widely used in the treatment of various skin diseases such as herpes zoster, pityriasis rosea, psoriasis and the like. The ultraviolet rays used in this treatment mainly use narrow-spectrum UVB to generate a photochemical reaction by ultraviolet irradiation to regulate the human immune response. For example, some patients with psoriasis need to be exposed to ultraviolet light for 3 minutes each time, and the course of treatment is up to thirty or fifty times. "UV is one of the causes of skin cancer, but the risk of cancer depends on the time and power." Professor Wen Ju said that dermatology uses hand-held UV lamps to diagnose some skin diseases. For doctors, every day in UV light At least one hour of exposure is not a big risk to your health.
Editor: Yingzi
Product Description
SPD Surge Protective Device,Lightning Surge Protector
Surge Protection Device (SPD)
It is a device used to limiting instant surge voltage and discharge surge current, it at least including a non-linear component.
Surge protective Device Model Selection
With the impact of international information flow, the rapid development of microelectronic science and technology, communication, computer and automatic control technology, make the building start to go for high quality, high functional area, formed a new building style-intelligent building. As inside the intelligent building there are lot of information system, <<Building lightning protection design norm>> GB50057-94(2002 vision)(hereafter brief as <<lightning protection norm>>) put forward the relative requirement to install the surge protective device, to ensure the information system safely and stable running.
SPD essentially is a equipotential connection material, its model selection is according to the different lightning protection area, different lightning electromagnetic pulse critical and different equipotential connection position, decide which kind of SPD used in the area, to achieve the equipotential connection with the common earth electrode. Our statement will based on SPD's maximum discharge current Imax, continuous operating voltage Uc, protection voltage Up, alarm mode etc.
As per << Lightning Protection Norm>> item 6.4.4 stipulation "SPD must can withstand the expected lightning current flow and should confirm to the additional two requirements: the maximum clamp voltage during surge across, capable to extinguish the power frequency follow-on current after lightning current across." That is the value of SPD's max. clamp voltage add its induction voltage of two ends should be same with the system's basic insulation level and the equipment allowed max. surge voltage.
SPD for Power Supply System Series Selection Guide
The installation of SPD at each lightning protection zone, according to the standard of low voltage electrical appearance, make classification of electrical equipment in accordance with the over voltage category, its insulation withstand impulse voltage level can determine the selection of SPD. According to the standard of low voltage electrical appearance, make classification of electrical equipment in accordance with the over voltage category as signal level, loading level, distribution and control level, power supply level. Its insulation withstand impulse voltage level are:1500V,2500V,4000V,6000V. As per to the protected equipment installation position different and the different lightning current of different lightning protection zone, to determine the installation position of SPD for power supply and the break-over capacity.
The installation distance between each level SPD should not more than 10m, the distance between SPD and protected equipment should as short as possible, not more than 10m. If due to limitation of installation position, can't guarantee the installation distance, then need to install decoupling component between each level SPD, make the after class SPD can be protected by the prior class SPD. In the low voltage power supply system, connecting an inductor can achieve the decoupling purpose.
SPD for power supply system specification selection principle
Max. continuous operating voltage: bigger than protected equipment, the system's max. continuous operating voltage.
TT System: Uc≥1.55Uo (Uo is low voltage system to null line voltage)
TN System: Uc≥1.15Uo
IT System: Uc≥1.15Uo(Uo is low voltage system to line voltage)
Voltage Protection Level: less than the insulation withstand impulse voltage of protected equipment
Rated discharge current: determined as per to the lightning situation of the position installed and lightning protection zone.
SP1 Series
Normal Working Conditions
-Altitude not exceed 2000m
-Ambient air temperature:
Normal range: -5ºC~+40ºC
Extend range: -40ºC~+80ºC
-Relative Humidity: 30% - 90% under indoor temperature condition
- At the place without obviously shaking and shock vibration
- Non-explosion danger medium, non-corrosion gas and dust ( including conductive dust)
Classification
-As per Nominal Discharge Current:
5,10,20,30,40,60KA(8/20µs)
- As per Maximum continuous operating voltage:
275V,320V,385V,420V,440V,460V
- As per to poles
1P,1P+N,2P,3P,3P+N,4P
- As per auxiliary functions:
a. With remote signal output ( remote alarm function)
b. Without remote signal output
Selection Principle
- The continuous applied voltage on the two terminals of SPD should not more than the maximum continuous operating voltage Uc value;
- The voltage protection level Up of SPD should less than the maximum impulse withstand voltage of the protected equipment;
- As per to the different earthing system and protection mode to select the specification accordingly;
Product Features
1, built-in over-current overheating, temperature control circuit technology.
2, the module design, easy installation, online replacement.
3, low leakage current, fast response time, low residual voltage.
4, alarm indication device, green (normal) v red (fault).
| Model/Technical Parameters | WR-B60 | WR-B80 | WR-B100 | WR-B120 | WR-B150 |
| Rated Operating Voltage Un (V ~) | 220V 380V | 220V 380V | 220V 380V | 220V 380V | 220V 380V |
| Maximum Continuous Operating Voltage Uc (V ~) kV | 385V 420V | 385V 420V | 385V 420V | 385V 420V | 385V 420V |
| Voltage Protection Level Up (V ~) kV | ≤1.8≤2.2 | ≤2.4≤2.5 | ≤2.5≤3.2 | ≤3.4≤3.7 | ≤4.0≤4.5 |
|
Maximum Discharge Current Imax(8/μ20μs)kA |
60 | 80 | 100 | 120 | 150 |
|
Nominal Discharge Current In(8/μ20μs)kA |
30 | 40 | 60 | 80 | 100 |
| Response Time | <25 | <100 | |||
| L/N(mm²)The Cross Section Of L/N Line | 16,25 | 16,25 | 16,25 | 16,25 | 25,35 |
| PE (mm²)The Cross Section Of PE Line | 16,25 | 25,35 | 25,35 | 25,35 | 35 |
| Fuse or Switch (A) | 63A | 63A | 63A,100A | 63A,100A | 63A,125A |
| The Line Section of Communication and Alarm (mm²) | ≥ 1.5 | ||||
|
Operating Environment-C |
(-40ºC~-+85ºC) | ||||
| Relative humidity 25 ºC | ≤95% | ||||
| installation | Standard Rail35mm | ||||
| Material of Outer Covering | Fiber Glass Reinforced Plastic | ||||
Surge Protector SPD,Surge Protection Device SPD,SPD
Wenzhou Korlen Electric Appliances Co., Ltd. , https://www.zjmotorstarter.com