A 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). In addition, in some cases, the goal is not to clean, but to collect deposits on the filter, which can be of much greater value.
Definition
Filtering is the process of dividing a relatively homogeneous substance into several components. As a rule, other elements stand out from the total mass that remains unchanged after cleaning. The easiest way to consider this process is the example of water. As you know, in the modern world, you can’t drink water, even from supposedly unpolluted water bodies. What flows from the tap also does not fit the definition of clean water. As a result, it must be run through the filter before use. It will remain harmful elements, and the final product will be, if not completely safe, then at least not as harmful as the original.
Why is it necessary
About water has been said above, there is nothing more to add. If you drink unfiltered liquid in which heterogeneous mixtures are present, it will not end in anything good. Salts will be deposited in the body (or washed out, depending on the type of water), pathogens can enter and many other problems may arise. In industry, unfiltered water can cause the breakdown of expensive equipment. In addition, if water is used as one of the main elements of the production cycle, it should be as clean as possible, otherwise the final product will be very far from what was declared. In addition to water, various gases are often filtered. In large enterprises, this is necessary so that employees do not ruin their own health too much. In addition, few people know about standard gas masks that can save a person’s life (both in the case of an enemy attack and in a banal fire). But this is also a filter, albeit somewhat peculiar.
Classification
For a better understanding of the topic, you should name and consider different types of filtering. This will help to clearly understand the characteristics of each variety, their properties, positive and negative sides, as well as effectiveness.
1. According to the operating mode of the filter:
This is the first type of filter separation. In the first case, the device is able to work stably for a long time, without requiring additional maintenance. We will return again, for example, with water. It can flow through the filter at a constant speed and should not “end”. Such devices usually use a large number of elements, each of which, without interfering with the speed of passage of the liquid, removes part of the harmful impurities.
The second option, with a periodic system of work, usually gets some kind of bulk container in which filtered water accumulates, and from there it can be taken for your own needs. The main disadvantage of such a filter is that with active use, the liquid quickly ends and it takes a long time to wait until it accumulates again. But such systems are usually much cheaper.
2, By filtering method:
In the first case, water, gas or another mixture is supplied to the filter under pressure, as a result of which the substance itself is quickly purified, and the precipitate is substantially compacted. The cheapest types of devices use their own mixture pressure without additional mechanical devices. The vacuum option in this case is more profitable, since it helps to clean the substance with the same success, but at a lower cost. True, it is technically more difficult to implement.
Pressure Filtration
Among all cleaning options, this is the easiest way. Filtering water using this system is very fast. To simplify the process in the cheapest types of filters, water, gas or any other substance requiring cleaning is supplied immediately under pressure. In more expensive devices, several compartments isolated from each other can be used, which can be replaced alternately without stopping the operation of the entire device. And despite the name, only sometimes does the system of forced pressure actually apply directly inside the device itself.
Vacuum Filtering
Such a system, as already mentioned, although technically more complicated, is more effective in terms of cleaning and general usability. Vacuum filtration involves the placement of a specific container where the mixture in need of processing enters. Further, a vacuum is created under the filter surface itself, literally stretching the main substance and leaving a precipitate. Filtering methods are thus divided according to the system of work, since one of the main disadvantages is the problem of the need for cleaning. They use carousel, disk, drum and any other similar mechanisms in which the components can be replaced almost immediately without problems. This allows you to maintain the desired level of efficiency of the device with minimal cost and without stopping it.
Filter materials
Since ancient times, mankind has been using various methods and devices to get rid of heterogeneous mixtures. The oldest and most famous of them is the sand filter. The principle of its operation is very simple. As you know, sand has the ability to pass water, but to hold 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 the following: the sand coalesces and after a short time ceases to fulfill its functions, requiring replacement. Later, a more effective option based on charcoal or activated carbon appeared. Structures on this basis work longer, but are still not good enough for full long-term use. That is why now, such substances as pressed titanium, asbestos, polymers, porous glass and so on are used as filter materials . With the development of technology, specialized artificial substances began to appear, which have a unique structure that can qualitatively capture all harmful elements, but skip the base.
Using
Filtering is a process that we face in everyday life constantly. Take the same tap water. Before it gets to our apartment, this liquid first passes through a serious cleaning and disinfection system. True, the final result is still unsatisfactory (especially in some regions), which is why many people put additional filters at home. The air we breathe in crowded places is often air-conditioned, especially if it is hot outside. In fact, it is the same, but passed through several filters, which makes it at least a little bit cleaner. And this can be said about almost any area of ​​human activity. Smokers generally constantly come into contact with filters, because they are built into cigarettes, and without them harm to the body would be outrageous (the truth is, the producers are guilty rather than saturating their products with pure tobacco, but with some suspicious mixtures with a lot of chemicals) .
Summary
This is not to say that one of the filters is the most effective. Filtering methods are directly dependent on the requirements. 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 cost of other types of products would be too much. And sand is relatively cheap. It is recommended to choose a filter not by the method of cleaning, but by the ease of use, the amount of contaminants, the speed of work and many other criteria, because no device still gives an ideal result.