Very large number of substances, especially liquid and gaseous, need to be filtered. This is a prerequisite for obtaining a pure substance (or as pure as possible). Also, in some cases, the goal is not to clean, but to collect deposits on the filter, which can be of much greater value.
Definition
Filtration is the process of separating a relatively homogeneous substance into several components. As a rule, other elements are isolated from the total mass that remains unchanged after cleaning. The easiest way to consider this process is on the example of water. As you know, in the modern world it is impossible to drink water, even from allegedly unpolluted reservoirs. What flows from the tap also does not fit the definition of clean water. As a result, it must be filtered before use. Harmful elements will remain on it, and the final product will be, if not completely safe, then at least not as harmful as the original.
Why is it needed
Water has already been mentioned above, there is nothing more to add here. If you drink unfiltered liquid, in which heterogeneous mixtures are present, nothing goodit won't end. S alts will be deposited in the body (or washed out, depending on the type of water), pathogens can enter, and numerous other problems will arise. In industry, unfiltered water can cause damage to expensive equipment. In addition, if water is used as one of the main elements of the production cycle, it must be as pure as possible, otherwise the final product will be very far from the declared one. In addition to water, various gases are often filtered. In large enterprises, this is necessary so that employees do not ruin their own he alth too much. In addition, few people do not know about standard gas masks that can save a person's life (both in the event of an enemy attack and in a banal fire). But this is also a filter, albeit somewhat peculiar.
Classification
For a better assimilation of the topic, you should name and consider different types of filtering. This will help to better understand the features of each variety, their properties, positive and negative sides, as well as effectiveness.
1. By filter mode:
- Permanent.
- Periodic.
This is the first way to divide filters into types. In the first case, the device is able to work stably for a long time without requiring additional maintenance. Let's go back to the water example. It can flow through the filter at a constant rate and should not "run out". In such devices, a large number of elements are usually used,each of which, without interfering with the speed of passage of the liquid, removes some of the harmful impurities.
The second option, with a periodic system of work, usually receives some volumetric container in which filtered water accumulates, and from there it can be taken for one's own needs. The main disadvantage of such a filter is that with active use, the liquid quickly ends, and it will take a long time to wait until it accumulates again. But such systems are usually much cheaper.
2, By filtering method:
- Pressure.
- Vacuum.
In the first case, water, gas or other mixture is fed into the filter under pressure, as a result of which the substance itself is quickly cleaned, and the sediment is significantly compacted. The cheapest types of devices use their own mixture pressure without additional mechanical devices. The vacuum option in this case is more profitable, as it helps to purify the substance with the same success, but at a lower cost. True, it is technically more difficult to implement.
Pressure filtering
Among all the cleaning options, this is the easiest way. Purification of water by filtration with this system is very fast. To simplify the process, in the cheapest types of filters, water, gas or any other substance that needs to be cleaned is supplied immediately under pressure. More expensive devices may use several isolated bays that can be replaced one at a time without stopping the entire operation.devices. And despite the name, only sometimes a system of forced pressure generation is actually used already directly inside the device itself.
Vacuum filtering
Such a system, as already mentioned, although technically more difficult, but more efficient in terms of cleaning and overall ease of use. Vacuum filtration involves the placement of a certain container, where the mixture that needs to be processed enters. Further, already under the filtering surface itself, a vacuum is created, literally pulling out the main substance and leaving a precipitate. Filtration methods are thus divided according to the system of work, since one of the main disadvantages is the problem with the need for cleaning. They use carousel, disk, drum and any other similar mechanisms in which the components can be replaced almost instantly without any problems. This allows you to maintain the desired level of efficiency of the device with minimal cost and without stopping it.
Filter media
In order to get rid of heterogeneous mixtures, mankind has been using various methods and devices since ancient times. The oldest and most famous of them is the sand filter. The principle of its work is very simple. As you know, sand has the ability to pass water, but retain various suspensions and other elements. The result is, if not crystal clear, then close to that water. The main disadvantage of such a device is as follows: the sand cakes and after a shorttime ceases to fulfill its functions, in need of replacement. Later, a more effective option appeared, based on charcoal or activated carbon. Designs on this basis last longer, but are still not good enough for full-fledged long-term use. That is why substances such as pressed titanium, asbestos, polymers, porous glass, and so on are now used as filter materials. With the development of technology, specialized artificial substances began to appear, with a unique structure that can qualitatively capture all harmful elements, but skip the base.
Use
Filtering is a process that we face in everyday life all the time. Take the same tap water. Before it enters our apartment, this liquid first passes through a serious cleaning and disinfection system. True, the end result is still unsatisfactory (especially in some regions), which is why many install additional filters already at home. The air we breathe in crowded places is often conditioned, especially when it's hot outside. In fact, it is the same, but passed through several filters, which makes it at least a little, but cleaner. And the same can be said about almost any sphere of human activity. Smokers in general are constantly in contact with filters, because they are built into cigarettes, and without them the harm to the body would be prohibitive in general (here, however, manufacturers are more likely to blame, saturating their products withnot pure tobacco, but some suspicious mixtures with a lot of chemicals).
Results
It is impossible to say that any of the filters is the most effective. Filtering methods directly depend on the requirements that have arisen. For example, the same sand filter is often used to clean pools, since there you need to work with very large volumes of water, and the costs for other types of products would be too high. And sand is relatively cheap. It is recommended to choose a filter not by the method of cleaning, but by ease of use, the amount of pollution, speed of operation and many other criteria, because no device still produces an ideal result.
