Among the many types of heaters that transfer heat through radiation, ultraviolet devices occupy a special position. These devices, called heaters, perform two functions, and one of them — heating, which is usually perceived in heaters as the main one, is not.
To have an idea about these devices and their application, let’s take a closer look at ultraviolet heaters.
Ultraviolet as a component of the light spectrum
The simplest example of electromagnetic radiation is sunlight. The radiation spectrum of the Sun is complex in composition, but it can be decomposed into 3 components — 3 groups of electromagnetic waves that are in a certain range of lengths:
- light visible to the eye;
- ultraviolet radiation;
- infrared electromagnetic waves.
Questions by definition visible light does not arise — this is what makes the human eye see the surrounding objects in the daytime. If you pass daylight through a crystalline prism, it becomes clear that white sunlight consists of seven basic color components — red, orange, yellow, green, blue, indigo and violet, the boundaries between which are fuzzy.
A seven-color rainbow in the sky in sunny weather after rain is nothing more than the visible spectrum of sunlight, decomposed into components by refraction when passing through the smallest drops of water in the air. The table shows the ranges of the location of the color components along the wavelength, and it can be seen that the minimum wavelength is for violet radiation.
Ultraviolet radiation by definition, it consists of even shorter wavelengths, the length of which is in the range of 10-400 nanometers, therefore it can be conventionally located below the purple segment. Electromagnetic waves of this length are not visible to the human eye, but a significant part of them (with a wavelength of 300-400 nm) penetrate the protective ozone layer of the atmosphere, and their impact on the environment is significant, although the degree depends on the season.
Ultraviolet is detrimental to pathogens, but it is necessary for the process of plant photosynthesis and the production of vitamin D in the human body, the lack of which causes the development of a serious disease — rickets. Small doses of ultraviolet radiation received by a person on the beach have a beneficial effect on the body, but an overdose of this natural factor will cause redness or even burns of the skin, and its regular prolonged exposure provokes the development of cancer.
These characteristics of ultraviolet radiation determine its use primarily as a disinfectant and healing (in small doses) factor, and heating is just an inevitable concomitant factor in the impact of these electromagnetic waves.
Infrared (long wave) radiation in the diagram, it is conditionally located above the region of the red spectrum and is also not visible to the human eye. But the result of exposure to waves of this wavelength range occurs much faster than that of ultraviolet, so this effect is thermal. Long-wave radiation does not affect the transit medium, but acts directly on objects whose surfaces it reaches — the molecules of the object begin to vibrate to a certain depth from the surface, and the temperature of the object rises, in turn causing heat to be emitted by it.
UV heater device
Currently, a lot of devices are used that emit ultraviolet radiation and, in close proximity, objects that heat the surface. The co-heating factor has led to the simplified name of these devices as heaters, although their main function is not heating at all. The design of most ultraviolet heaters is a housing with or without a reflector, which houses an ultraviolet emitter — a special lamp.
These devices are most often used in medical institutions, solariums, swimming pools, SPA-salons and other institutions that practice artificial tanning or need regular disinfection of rooms and equipment.
blue light lamp
Ultraviolet heaters, using a special so-called blue lamp as an emitter, are produced in different designs. These can be powerful stationary wall and ceiling devices or portable tripod devices with adjustable height and angle of radiation, wall-mounted products or hand-held devices (Minin reflector).
In all these devices, the emitter is an ultraviolet lamp of various power, the principle of operation of which is identical to its luminescent variety.
The device of the «blue light lamp» and its varieties
Two electrodes are placed in a tubular flask made of quartz or uviol glass, coated on the inside with a special phosphor and filled with mercury vapor. When voltage is applied to the electrodes, mercury vapor under the influence of a discharge between them begin to glow, and the phosphor transmits only ultraviolet rays.
UV radiation contributes to the formation of ozone in the air, which in large quantities is harmful to humans.
Important! Lamps with uviol glass bulbs produce less ozone in the air during operation, therefore they are considered safer.
Types and applications of UV devices
UV lamps by functionality are divided into three groups:
- open type — lamps of significant power for disinfection of premises, from which people, animals and plants are previously removed;
- closed type — powerful lamps located in a special isolated chamber through which air from a room with people is passed for disinfection;
- special purpose — low-power ultraviolet lamps for physiotherapy procedures, including at home.
By design UV heaters classified into the following types:
- portable tripod execution;
- portable compact.
Stationary ultraviolet heaters
UV devices of this type include devices located in separate chambers to disinfect the air passed through them, as well as wall and ceiling devices that are switched on periodically in the absence of people.
Some models (recirculators) can be operated in the presence of a person. Air disinfection in them is carried out by forced circulation through the body of the device with UV lamps located inside.
The power of such devices is selected in accordance with the dimensions of the room or the throughput of the chamber.
Stationary UV devices also include water disinfection products in pools, produced due to work under water in sealed cases. Irradiation of water with ultraviolet light is used in addition to its treatment with chemical reagents to achieve a better cleaning result.
Water is passed through a long channel of small cross-sectional area, subjected to prolonged UV exposure. This design provides a high degree of water disinfection and eliminates the formation of salt deposits on the device walls that prevent the disinfection process. The kit includes brackets for mounting on the walls of the pool.
One such device is designed for a pool up to 100 cubic meters.
Stand-mounted portable UV units
Stand-mounted UV instruments are used for regular disinfection of premises in medical and children’s institutions, as well as in physiotherapy rooms for general and local UV irradiation for therapeutic and prophylactic purposes. Their weight is negligible and allows you to transfer equipment to the place of need for use.
In addition to disinfection, UV devices of this type are used to achieve a vitamin-forming, anti-inflammatory, immunomodulatory and analgesic effect in patients of medical and preventive institutions.
Portable compact ultraviolet heaters
An example of a compact UV heater is a blue lamp with a reflector, placed for ease of use in a dielectric case with a handle — a Minin reflector. This device has been successfully used in medicine for many years for local heating in the treatment of inflammation of the hearing and respiratory organs. The radiation power of the reflector is low — it is limited by the value necessary for the procedures, the duration of the session is also strictly regulated, therefore this device does not have a negative effect on the human body, and the combination of exposure to heat and ultraviolet radiation reduces the recovery rate by several times.
Other devices using ultraviolet light
Devices for sterilization and storage of medical instruments, cosmetic devices can also be made using the disinfecting properties of ultraviolet radiation. At the same time, the material for the manufacture of tools does not matter, whether metal, plastic or combined products are disinfected with the same quality. Short processing time — 15-20 minutes, compactness, efficiency and economy — this is not the whole list of advantages of these devices over conventional thermal sterilizers.
In modern dentistry, light curing fillings are widely used, which occurs after a narrow beam of UV radiation is directed at the material.
Important! Eye protection is required during UV exposure to avoid corneal burns.
Ultraviolet heaters are indispensable in spas for the safe and comfortable use of wet towels and tampons, which are simultaneously heated and disinfected in special heaters that use UV radiation.
In everyday life, UV heaters are often used in the form shoe dryers from within. In this case, not only the removal of moisture occurs, but also the antibacterial treatment of the hard-to-reach inner part of the shoe with the destruction of bacteria — a source of fungal diseases and an unpleasant odor.
Automatic detectors for determining the authenticity of banknotes also use UV rays in their work, in the light of which modern elements of protecting banknotes from counterfeiting appear.
A car is a daily companion of most people, and today its diagnostics are also carried out using ultraviolet radiation. For this, ultraviolet detector flashlights are produced, with the help of which it is easy to detect an antifreeze leak from a car engine cooling system or freon from a car air conditioner harness.
Such a detector can also determine the location of an oil leak if a special UV dye is added to the lubricating fluid, which does not change its technical characteristics.
Advantages and disadvantages of ultraviolet devices
The positive characteristics of heaters and other devices that use UV radiation are numerous, which leads to their widespread use in medicine, industry, everyday life, forensics and many other industries.
As for the negative factors, the main one is the negative impact on living organisms. However, it should be noted that it is not difficult to avoid this influence — you just need to follow the rules for operating devices using ultraviolet radiation and observe safety precautions. Recommendations for the use of each UV device are individual, but there are general ones for everyone — avoid prolonged exposure to ultraviolet radiation, regardless of the source of radiation, and, most importantly, do not expose your eyes to radiation.
Despite the negative effects of UV radiation, the role of ultraviolet heaters in today’s life can not be overestimated, and their use continues to expand with the simultaneous improvement of measures for safe operation. Using devices intended for domestic use in everyday life and following the manufacturer’s instructions, we make life easier for ourselves. And industrial devices should be operated by professionals. Substitution of scopes is unacceptable.