Metal-plastic windows have come to us to replace ordinary wooden ones, which are now considered a very outdated technology. Complex glass has replaced ordinary glass in frames. engineering solutions in the form of double-glazed windows. They are a multilayer structure, which consists of thick glasses and absolutely sealed chambers between them, which are filled with special gases that have certain properties.

Double-glazed windows are significantly superior to their predecessors - ordinary glass - in all operational parameters. A properly installed and configured metal-plastic window with a good double-glazed window guarantees the complete absence of drafts and the elimination of so-called “cold bridges.” Neither moisture, nor cold, nor even noise can disturb the microclimate you have created in your home. Such high performance is achieved thanks to special manufacturing technology. Below we will look at their structure and figure out how they differ and which double-glazed window you need to choose during installation.

Single chamber

This is the easiest to make, cheapest and most common type. It is a structure of two glasses 3 or 4 millimeters thick, which are separated by a sealed space 14 millimeters wide.

Thus, these dimensions represent the formula used to calculate the double-glazed window

4-14-4 .

The elements are hermetically connected to plastic frame, forming a hollow space between them. Epoxy sealant and desiccant are poured onto the side of the frame, which prevents moisture from penetrating through the seams of the frame into the room. The space is completely sealed and filled with either dry air or an inert gas (argon or krypton). Replacing ordinary air inside the chamber with inert gas increases the energy efficiency of the window by approximately 6-7%.

For reference!

More expensive single-chamber options are equipped with glass of greater thickness - 6 millimeters. To achieve the maximum level of ergonomics, conventional options are replaced with energy-saving ones.

As mentioned above, the main reason for choosing this type among modern consumers is its little weight And low cost. However, the minimum amount of glass allows the window to sweat and freeze already at a temperature of -9 degrees. Therefore, they are not recommended for installation in ordinary residential premises or children's rooms. They are most often used on verandas, balconies or loggias. You can also place it in a living room, but the air in it must be dry and the room itself must be well ventilated. Increasing the distance between components by 2 millimeters leads to an increase in the size and capacity of the gas chamber, which improves the insulating properties.

Double chamber

The next “level of development” of double-glazed windows is the installation of three glasses with the formation of two sealed chambers between them. The thickness of the structural components also varies - you can install glass 3, 4 and 6 millimeters thick, and cameras made 14 and 16 millimeters in size. The manufacturing technology is similar to that described above, but the performance properties deserve special attention.

On average, a two-chamber one is almost one and a half times warmer than a one-dimensional one, and moisture condensation and freezing occur already at twenty degrees below zero. Such indicators are due to an increase in the number of layers in the structure. First, the outer layer cools, followed by a drop in the temperature in the first chamber. Condensation no longer forms inside the room, but on the second layer, preventing moisture from penetrating inside. The space inside which moisture collects is filled with hygroscopic materials. The cooling chain reaction continues until the last layer inside the room. A high-quality double-glazed window will practically not allow the last glass to cool, which will retain a huge amount of heat inside the rooms.

For reference!

Increasing the distance between the components increases the already high sound insulation performance of the window. Combination various types glass will give the window greater protection from direct ultraviolet radiation sunlight and improves energy efficiency.

Three-chamber

An extreme method of dealing with harsh weather conditions in the form of constant high humidity and very severe frosts (up to -50) is installation, which form three sealed chambers among themselves. This design is also recommended for installation in houses that are located near transit highways, train stations or airfields, as it has the highest noise insulation properties. The window with four glasses is indifferent to severe frosts, hail, and torrential rains, and is practically unbreakable.

The thickness of a double-glazed window with minimal component sizes starts from 8 centimeters. It is very heavy, which puts a lot of stress on the building wall and frame, so during installation you need to carefully study it so that it is not pressed or destroyed.

• Due to the large number of glasses, such a window transmits by a third less light than its predecessor.
• Another disadvantage is the high cost. The advantages include increased insulation (50-60% higher than that of a two-chamber one).

Price

The cheapest and most common option is a single-chamber design. It is easy to manufacture, relatively light, and has all the qualities necessary for the average resident.

The next generation is more expensive - two-chamber. However, when choosing a double-glazed window, price should not primarily influence your decision. The higher ergonomics of double-chamber windows allow them to pay for themselves after several years of use and continue to save money on heating your home in the future. This does not apply to structures with four or more glasses. They are too expensive and heavy to be installed in non-special conditions. In addition to the high cost of the double-glazed window itself, you will also have to pay money for the installation of a special frame of increased strength, so it will take more than a dozen years before you break even on the cost of them.

Energy Saving Technologies

The latest technology for installation metal-plastic windows is a replacement for conventional glass. Their properties are based on a special technology, which involves applying special coating on inner side glass It misses thermal energy inside the room, but does not allow it to go out through the windows. Single-chamber options with energy-saving glass have higher performance indicators than double-chamber options with conventional solutions, and they are also lighter.

Filling with argon increases thermal insulation by 10-12%. However, it tends to evaporate, so after ten years such a double-glazed window will turn into an ordinary one.

Conclusion

The choice of a double-glazed window should be justified by the need for it. You should not install thick structures in regions with warm climates; you will get nothing but huge costs. Thin windows are useless in cold regions; they will deteriorate after just a few seasons. The best option is to choose a single-chamber option with energy-saving components or an ordinary two-chamber one.

In the video, the expert explains how to choose the right double-glazed windows for your home and what features each type has.

A Tesla coil is a high-frequency resonant transformer without a ferromagnetic core, which can be used to obtain high voltage on the secondary winding. Under the influence of high voltage in the air, an electrical breakdown occurs, similar to a lightning strike. The device was invented by Nikola Tesla, and bears his name.

According to the type of switching element of the primary circuit, Tesla coils are divided into spark (SGTC - Spark gap Tesla coil), transistor (SSTC - Solid state Tesla coil, DRSSTC - Dual resonant solid state Tesla coil). I will only consider spark coils, which are the simplest and most common. According to the method of charging the loop capacitor, spark coils are divided into 2 types: ACSGTC - Spark gap Tesla coil, and DCSGTC - Spark gap Tesla coil. In the first option, the capacitor is charged with an alternating voltage; in the second, a resonant charge is used with a constant voltage applied.

The coil itself is a structure of two windings and a torus. The secondary winding is cylindrical, wound on a dielectric pipe with copper winding wire, in one layer turn to turn, and usually has 500-1500 turns. The optimal ratio of the diameter and length of the winding is 1:3.5 – 1:6. To increase electrical and mechanical strength, the winding is coated epoxy glue or polyurethane varnish. Typically, the dimensions of the secondary winding are determined based on the power of the power source, that is, the high-voltage transformer. Having determined the diameter of the winding, the length is found from the optimal ratio. Next, select the diameter of the winding wire so that the number of turns is approximately equal to the generally accepted value. Sewer pipes are usually used as a dielectric pipe. plastic pipes, but it is possible to make homemade pipe, using sheets of drawing paper and epoxy glue. Hereinafter we are talking about medium coils, with a power of 1 kW and a secondary winding diameter of 10 cm.

A hollow conducting torus, usually made of aluminum, is installed at the upper end of the secondary winding pipe. corrugated pipe for removal of hot gases. Basically, the diameter of the pipe is selected equal to the diameter of the secondary winding. The diameter of the torus is usually 0.5-0.9 times the length of the secondary winding. The torus has an electrical capacitance, which is determined by its geometric dimensions, and acts as a capacitor.

The primary winding is located at the lower base of the secondary winding, and has a spiral flat or conical shape. Typically consists of 5-20 turns of thick copper or aluminum wire. High-frequency currents flow in the winding, as a result of which the skin effect can have a significant influence. Due to the high frequency, the current is distributed predominantly in the surface layer of the conductor, thereby reducing the effective cross-sectional area of ​​the conductor, which leads to an increase in active resistance and a decrease in the amplitude of electromagnetic oscillations. That's why the best option for the manufacture of the primary winding will be hollow copper tube, or flat wide tape. An open protective ring (Strike Ring) from the same conductor is sometimes installed above the primary winding along the outer diameter and grounded. The ring is designed to prevent discharges from entering the primary winding. The gap is necessary to prevent current flow through the ring, otherwise the magnetic field created by the induction current will weaken the magnetic field of the primary and secondary windings. The protective ring can be dispensed with by grounding one end of the primary winding, and the discharge will not harm the coil components.

The coupling coefficient between the windings depends on their relative position, the closer they are, the greater the coefficient. For spark coils, a typical coefficient value is K=0.1-0.3. The voltage on the secondary winding depends on it; the higher the coupling coefficient, the higher the voltage. But it is not recommended to increase the coupling coefficient above the norm, since discharges will begin to jump between the windings, damaging the secondary winding.


The diagram shows simplest option Tesla coils type ACSGTC.
The operating principle of a Tesla coil is based on the phenomenon of resonance of two inductively coupled oscillatory circuits. The primary oscillatory circuit consists of a capacitor C1, a primary winding L1, and is switched by a spark gap, resulting in a closed circuit. The secondary oscillatory circuit is formed by the secondary winding L2 and capacitor C2 (a toroid with capacitance), the lower end of the winding must be grounded. When the natural frequency of the primary oscillatory circuit coincides with the frequency of the secondary oscillatory circuit, there is a sharp increase in the amplitude of voltage and current in secondary circuit. At a sufficiently high voltage, electrical breakdown of the air occurs in the form of a discharge emanating from the torus. It is important to understand what a closed secondary circuit is. The secondary circuit current flows through the secondary winding L2 and capacitor C2 (torus), then through air and ground (since the winding is grounded), the closed circuit can be described as follows: ground-winding-torus-discharge-ground. Thus, the exciting electrical discharges are part of the circuit current. If the grounding resistance is high, the discharges emanating from the torus will hit directly the secondary winding, which is not good, so you need to do high-quality grounding.

Once the dimensions of the secondary winding and torus are determined, the natural frequency of oscillation of the secondary circuit can be calculated. Here we must take into account that the secondary winding, in addition to inductance, has some capacitance due to its considerable size, which must be taken into account when calculating; the winding capacitance must be added to the torus capacitance. Next, you need to estimate the parameters of the coil L1 and capacitor C1 of the primary circuit, so that the natural frequency of the primary circuit is close to the frequency of the secondary circuit. The capacitance of the primary circuit capacitor is usually 25-100 nF, based on this, the number of turns of the primary winding is calculated, on average it should be 5-20 turns. When making a winding, it is necessary to increase the number of turns compared to the calculated value in order to subsequently tune the coil to resonance. All these parameters can be calculated using standard formulas from a physics textbook; there are also books online on calculating the inductance of various coils. There are also special calculator programs for calculating all the parameters of the future Tesla coil.

The adjustment is carried out by changing the inductance of the primary winding, that is, one end of the winding is connected to the circuit, and the other is not connected anywhere. The second contact is made in the form of a clamp, which can be transferred from one turn to another, thereby not the entire winding is used, but only part of it, and the inductance and natural frequency of the primary circuit change accordingly. The tuning is carried out during preliminary launches of the coil; the resonance is judged by the length of the discharged discharges. There is also a method for cold tuning the resonance using an RF generator and an oscilloscope or RF voltmeter, without the need to run the coil. It is necessary to note that the electric discharge has a capacitance, as a result of which the natural frequency of the secondary circuit may decrease slightly during operation of the coil. Grounding may also have a small effect on the secondary frequency.

The spark gap is a switching element in the primary oscillatory circuit. When an electrical breakdown of the spark gap occurs under the influence of high voltage, an arc is formed in it, which closes the circuit of the primary circuit, and high-frequency damped oscillations arise in it, during which the voltage on capacitor C1 gradually decreases. After the arc goes out, the loop capacitor C1 begins to charge again from the power source, and with the next breakdown of the spark gap, a new cycle of oscillations begins.

The arrester is divided into two types: static and rotating. A static discharger consists of two closely spaced electrodes, the distance between which is adjusted so that an electrical breakdown between them occurs at a time when the capacitor C1 is charged to the highest voltage, or slightly less than the maximum. The approximate distance between the electrodes is determined based on the electrical strength of air, which is about 3 kV/mm under standard conditions environment, and also depends on the shape of the electrodes. For alternating mains voltage, the response frequency of the static discharge (BPS - beats per second) will be 100 Hz.

A rotating spark gap (RSG - Rotary spark gap) is made on the basis of an electric motor, on the shaft of which a disk with electrodes is mounted; static electrodes are installed on each side of the disk, thus, when the disk rotates, all the electrodes of the disk will fly between the static electrodes. The distance between the electrodes is kept to a minimum. In this option, you can adjust the switching frequency over a wide range by controlling the electric motor, which gives more opportunities for tuning and controlling the coil. The motor housing must be grounded to protect the motor winding from breakdown when exposed to a high-voltage discharge.

Capacitor assemblies (MMC - Multi Mini Capacitor) of series and parallel connected high-voltage high-frequency capacitors are used as loop capacitor C1. Typically, ceramic capacitors of the KVI-3 type are used, as well as film capacitors K78-2. Recently, a transition to paper capacitors of the K75-25 type has been planned, which have shown good performance. For reliability, the rated voltage of the capacitor assembly should be 1.5-2 times the amplitude voltage of the power source. To protect capacitors from overvoltage (high-frequency pulses), an air gap is installed parallel to the entire assembly. The spark gap can be two small electrodes.

A high-voltage transformer T1, or several series- or parallel-connected transformers, is used as a power source for charging the capacitors. Basically, novice Tesla builders use a microwave oven transformer (MOT - Microwave Oven Transformer), the output alternating voltage of which is ~2.2 kV, the power is about 800 W. Depending on the rated voltage of the loop capacitor, MOTs are connected in series from 2 to 4 pieces. The use of only one transformer is not advisable, since due to the small output voltage the gap in the spark gap will be very small, resulting in unstable results of the coil operation. The motors have the disadvantages of poor electrical strength, are not designed for long-term operation, and get very hot under heavy loads, so they often fail. It is more reasonable to use special oil transformers such as OM, OMP, OMG, which have an output voltage of 6.3 kV, 10 kV, and a power of 4 kW, 10 kW. You can also make a homemade high-voltage transformer. When working with high-voltage transformers, one should not forget about safety precautions; high voltage is dangerous to life; the transformer housing must be grounded. If necessary, an autotransformer can be installed in series with the primary winding of the transformer to regulate the charging voltage of the loop capacitor. The power of the autotransformer must be no less than the power of transformer T1.

The inductor Ld in the power circuit is necessary to limit the short circuit current of the transformer in the event of breakdown of the spark gap. Most often, the inductor is located in the secondary winding circuit of transformer T1. Due to the high voltage, the required inductance of the inductor can take large values from units to tens of Henry. In this embodiment, it must have sufficient electrical strength. With the same success, the inductor can be installed in series with the primary winding of the transformer; accordingly, high electrical strength is not required here, the required inductance is an order of magnitude lower, and amounts to tens, hundreds of millihenries. The diameter of the winding wire must be no less than the diameter of the wire of the primary winding of the transformer. The inductance of the inductor is calculated from the formula for the dependence of inductive reactance on the frequency of alternating current.

The low-pass filter (LPF) is designed to prevent the penetration of high-frequency pulses of the primary circuit into the inductor circuit and the secondary winding of the transformer, that is, to protect them. The filter can be L-shaped or U-shaped. The cutoff frequency of the filter is chosen to be an order of magnitude lower than the resonant frequency of the oscillatory circuits of the coil, but the cutoff frequency must be much higher than the response frequency of the spark gap.


When resonantly charging a loop capacitor (coil type - DCSGTC), a constant voltage is used, unlike ACSGTC. The voltage of the secondary winding of transformer T1 is rectified using a diode bridge and smoothed with capacitor St. The capacitance of the capacitor should be an order of magnitude greater than the capacitance of loop capacitor C1 to reduce DC voltage ripple. The capacitance value is usually 1-5 µF; for reliability, the rated voltage is chosen to be 1.5-2 times the amplitude rectified voltage. Instead of one capacitor, you can use capacitor assemblies, preferably not forgetting about equalizing resistors when connecting several capacitors in series.

High-voltage diode columns of the KTs201 type and others are used in series as bridge diodes. The rated current of the diode columns must be greater than the rated current of the secondary winding of the transformer. The reverse voltage of the diode columns depends on the rectification circuit; for reliability reasons, the reverse voltage of the diodes should be 2 times the amplitude value of the voltage. It is possible to manufacture homemade diode posts by connecting conventional rectifier diodes in series (for example 1N5408, Urev = 1000 V, In = 3 A), using equalizing resistors.
Instead of the standard rectification and smoothing circuit, you can assemble a voltage doubler from two diode columns and two capacitors.

The operating principle of the resonant charge circuit is based on the phenomenon of self-inductance of the inductor Ld, as well as the use of a cut-off diode VDо. At the moment when capacitor C1 is discharged, current begins to flow through the inductor, increasing according to a sinusoidal law, while energy accumulates in the inductor in the form magnetic field, and the capacitor is charged, accumulating energy in the form of an electric field. The voltage across the capacitor increases to the voltage of the power supply, while the maximum current flows through the inductor, and the voltage drop across it is zero. In this case, the current cannot stop instantly, and continues to flow in the same direction due to the presence of self-induction of the inductor. Charging of the capacitor continues until the power source voltage is doubled. A cut-off diode is necessary to prevent energy from flowing from the capacitor back to the power source, since a potential difference appears between the capacitor and the power source equal to the voltage of the power source. In fact, the voltage across the capacitor does not reach double the value due to the presence of a voltage drop across the diode column.

The use of a resonant charge makes it possible to more efficiently and evenly transfer energy to the primary circuit, while to obtain the same result (over the discharge length), DCSGTC requires less power from the power source (transformer T1) than ACSGTC. The discharges acquire a characteristic smooth bend due to a stable supply voltage, in contrast to ACSGTC, where the next approach of the electrodes in the RSG can occur in time at any section of the sinusoidal voltage, including reaching zero or low voltage and, as a result, a variable discharge length (ragged discharge).

The picture below shows the formulas for calculating the parameters of a Tesla coil:

I suggest you familiarize yourself with my construction experience.

Now tourists often wonder what they should take on a hike: a regular, proven foam mat or an innovative self-inflating mat? Some people don’t understand why a whole “inflatable mattress” is needed on a hike (though there is almost no resemblance to a mattress)? Others want to have at least some comfort outside of civilization, even if it’s just sleeping area, but what a comfort the traveler feels when using this miracle rug.

The founder and, to this day, the leading manufacturer is an American corporation called Cascade Designs, also known under the Therm-a-Rest brand (this rug is sometimes called after the company - Thermarest). Soon others began to produce them foreign companies, and in particular: Tramp, Pinguin, Hannah, Terra incognita and our Russian Nova Tour.

The self-inflating mat is a two-layer design. The inner layer consists of open-cell polyurethane foam, and the second is a hermetically sealed nylon or polyester shell. This filler has freely open pores that swell with air when the rug is laid out. The enveloping material is closely connected to the filler, which, in turn, does not allow air to escape from this shell, and does not allow water to be sucked inside.

In order for the mat to take its shape and take in air, you just need to unfold it and unscrew the valve cap.

In total, these actions will take 5 – 25 minutes, although in the end you will need to use the strength of your lungs, and in winter period the inflation process takes much longer. If you suddenly have little time, you can inflate the mat much faster, using a pump or, again, using your lungs.

A newly purchased self-inflating mat inflates much more slowly than one that has already been used several times, and thinner products are also more difficult to inflate.

Transportation questions

To transport the mat, you need to roll it out on the ground, then open the valve and roll it up as tightly as possible, gradually squeezing the air out of the porous structure. Then you need to tighten the valve and place the mat in the case.

Storage rules

The mat is best preserved and does not lose its properties in an unfolded position with the flap unscrewed.

Or, without such an opportunity, let it be rolled up, but not tightly and also with an open valve, otherwise you risk improper storage remove the unusable product (in a tightly rolled position with closed valve the mat may begin to peel). And most importantly, avoid rooms with high humidity, otherwise there will soon be a need to dry the entire product.

Features of washing thermorest

In order to wash the rug, lukewarm water and a regular sponge are enough, but if you think that it needs more thorough washing, then use soap solution. The valve must be in a tightened state. And after washing, be sure to dry it fresh air, open valve down.

Let's consider the advantages and disadvantages of such rugs

Perhaps, first of all, let’s turn our attention to the advantages of self-inflating mats.

The self-inflating mat retains heat perfectly, so you won't be afraid of hiking in winter time year, the test will be different - in cold air it is more difficult to inflate.

The second advantage lies in comfort, flexibility and convenience. Sleeping on it is a pleasure; you get the feeling that you are in your own warm bed, reminding you of home comfort. This is the quality for which travelers love such rugs very much.

• It is also resistant to stress and pressure.
• Quite compact.

But still there is back side, that is, disadvantages, now let's talk about them.
It would be useful to remind you to be careful when handling rugs; they can easily be punctured. It follows from this that before spreading the thermorest on the ground, it is necessary to remove all fragments, thorns, branches, if any, from that place. Otherwise, it can be damaged and it will no longer inflate. But it is best to lay such a rug in a shelter, that is, in a tent.

The presence of extraneous noise during use, similar to a plastic bag. If these sounds are unpleasant to you, then it is better to abandon the self-inflating mat. Thermal tests, unlike classic mats, have more weight, and if you went on a hike light, then it is better to give your preference to ordinary foam pads.

By the way, such mats always include a repair kit for repairing the product. And if suddenly you do pierce your rug, then you need to use this kit. It includes glue and several rather large patches.

Choice

And now we will look at the most important question: how to choose a self-inflating mat?

Most main criterion, by which thermorest is usually selected, is weight, as we already mentioned above.

And the main thing here is not to make a mistake; it all depends on what time of year you are buying a rug for. During the cold period, it is better to choose a product of greater height (4-5 cm) so that the thermal insulation is effective, and the weight of such products ranges from 1.1 to 1.3 kg on average.

For other periods, you can choose smaller options; a rug 3.8 cm thick will do; its weight can range from 460 to 1000 grams.

More experienced travelers warn that the most useless thermal rests on a hike are those that have a rubber shell. Rubber, as is known, has sufficient thermal conductivity, as a result of which we conclude: at night you can easily freeze on such a rug. And the correct material in this case is polyurethane.

Now you know a lot about what types of self-inflating mats there are, by weight, what they are made of and what structure they have, as well as the pros and cons of thermal rests.

It remains to mention how they should not be used under any circumstances. Do not use as a sled or air mattress at sea, or as a fan for a fire, it is also not suitable.

There are a few more points: you cannot inflate the product with the valve closed, otherwise, due to overheating of the air from the inside, it may inflate and come apart at the seams. We hope that our advice will help you when choosing and using miracle rugs.

Discussion: there is 1 comment

An interesting device, I’m thinking of taking one for my next trip to the sea. Otherwise, sleeping in a sleeping bag is somehow no longer an option, age is apparently taking its toll)) I read all the pros and cons, I promise that I will not use the mat as a sled or as a fan))

Answer

Before calculating the stairs, it is necessary to consider the main types of these structures.

Design of a simple staircase: 1 - channel; 2 - corrugated metal steps; 3 - steel “fillies”; 4 - welding places; 5 - brackets for fastening steps.

Straight stairs are the simplest type of this design. It is convenient to move around, including carrying heavy things. If in the house high ceilings, and the staircase consists of more than 18 steps, it is recommended to arrange an intermediate platform in the middle of the structure. The disadvantage of this type is the large occupied area.

Double-flight staircases have an intermediate platform and can be angled or U-shaped. Although this type is characterized by the presence of an intermediate platform, due to its configuration the design fits well into almost any room, including smaller ones. In the U-shaped type, the width of the intermediate platform must be no less than the width of both flights, which must be taken into account when calculating the stairs.

Winder stairs are a structure of two or more flights, in which special turning (winder) steps are used instead of intermediate platforms. Entering species require a minimum of free space and easily fit into limited spaces. The disadvantage of this type is the complexity of design, complex circuit stairs, as everything winder steps differ, have their own individual sizes. And stringers and railings also have complex curved shapes. Calculation of stairs of this type is also quite complicated.

A spiral staircase is the most economical type. The most optimal radius is 80-90 cm. The disadvantage of this design is that it is less convenient to move along it, the climb is steep, and it is very difficult to lift heavy and large items along it. The screw type is characterized by a complex design; the calculation of stairs is difficult, but they have an attractive and impressive appearance.

This type of staircase, such as “samba” or “ goose step"is also distinguished by its economical configuration. Home distinctive feature is a staircase diagram, namely half steps, which set the sequence of steps in strict adherence. Depending on the position of the first step, the lift will always start with one specific foot (right or left). This type is distinguished by its steep rise. Most often, this staircase design is used as an auxiliary one, for climbing to the attic, in conditions of extremely limited space.

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Calculation of stairs during design

If you need to install a staircase in your house, you will have to resolve many issues. And not only regarding the type and materials, but also the need to calculate the stairs.

After all, it’s not enough to come up with a model; you need to fit it correctly into the room, taking into account the area and height of the ceiling.

The first indicator that is necessary to calculate the stairs is the height from the floor of one floor to the edge of the floor of the next floor. If it's still in the house rough finish, then it is necessary to take into account the thickness of the finishing layer with all substrates, leveling materials, etc.

After this, the number of steps is calculated. To do this, the height of the room must be divided by the desired step. When receiving a fractional number, the calculation of stairs requires making an adjustment in the direction of decreasing or increasing the number of steps, according to which the step will increase or decrease.

Each staircase also has its own constant size: this is the width of the tread, the size of which is taken in the range from 130 to 225 mm. The parameter shows how much length must be left to accommodate the structure. This distance is obtained by multiplying the size of the tread by the number of steps. It is also necessary to add 80 mm to the resulting number, technical size, i.e. the distance allotted to the lunge of the first stage and part of the upper module. When building a staircase and calculating its width, it is necessary to take into account the size of the room and how much space can be allocated for the structure. The value is calculated according to the free area.

It is worth considering that if the staircase does not fit slightly into the dimensions of the room, you can use one trick. If thickness interfloor covering is more than 30 cm, then it is allowed to indent down by 15-17 cm. The remaining distance is quite enough to secure the structure.

The most important role in choosing a design is played by the dimensions of the opening. If it is too small (for example, width - 700-900 mm, length - 1100-1600 mm), then only a goose-step staircase can be fit into it.

Also, the design of the staircase and its shape depend on the desired step rise and the width of the tread.

It is worth noting that the smaller the step height, the correspondingly more steps, modules, balusters, and railings will be needed. And the longer the ladder will be.

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Formulas for calculating stair elements

To calculate the stairs, there are several formulas that will allow you to design the correct structure.

Among them is the ratio of the riser height a to the tread width b, which can be calculated using three formulas:

• convenience formula: b-a=12 cm;
• step formula: 2a+b=62 (60-64) cm;
• safety formula: a+b=46 cm.

The optimal ratio is 17/29, but the following deviations are allowed: tread: 26 ≤ b ≤ 32 on average 29, riser: 14 ≤ a≤ 20 on average 17.

The lifting height h depends on the height of the room H and the thickness of the floor D: h=H+D. The number of steps n is calculated by the formula: n=h/a.

The length of the projection of the staircase onto the floor plane l depends on the number of steps n and the width of the tread b and is calculated by the formula: l=b*n.

Next, you need to determine the steepness of the stairs k. It depends on the lifting height h (height from the floor of the lower floor to the floor of the upper) and the length of the projection of the structure onto the floor plane l. The slope is calculated using the formula: k=h/l.

The telescopic crown is a structure of two parts: primary and secondary. It is used primarily for fixation. The primary part is a metal cap. The secondary crown is fixed to the prosthesis frame. When two parts are connected, a strong structure is formed. With its help, you can form a strong mount for prostheses, which at the same time can be easily removed.

Types of telescopic crowns

This mechanism was first tested in Germany at the beginning of the last century. The telescopic crown owes its name to its resemblance to a telescope. Its components move relative to each other in the same way. Over almost a century of history, this design has managed to prove its practicality, ease of use and good aesthetics. Nowadays, telescopic crowns can serve as excellent alternative option prostheses on implants.

There are two varieties of this design - cylindrical crowns and conical ones. They mainly differ in appearance. The very first examples of telescopic crowns were made by craftsmen with cylindrical walls. They are characterized by a fairly tight fit. Today, it is advisable to use such a design only among patients with absolutely healthy gums.

The telescopic conical crown is an improved version of the cylindrical one. Its main advantage is considered to be the absence of the influence of errors that are possible at the manufacturing stage. This design does not allow distortion or jamming when fixing the prosthesis. The main disadvantage of the improved system is the possibility of the crowns detaching upon contact with food.

Advantages of telescopic crowns

Which positive sides can be noted in the application of this design?

1. The chewing load is evenly distributed over all teeth and gums.
2. No effect on diction and bite.
3. Possibility of installation on implants.
4. Long service time.
5. Easy to use and maintain.
6. Preserving dental health for a long time.

These are not all the advantages of telescopic crowns. Everyone can note for themselves the positive aspects of using the design.

Disadvantages of telescopic crowns

Among the main disadvantages of this design are the long production period and high cost. However, the negative aspects are fully compensated by the advantages of crowns listed above.

Indications for installation

The use of telescopic crowns is advisable in the following cases:

• the presence of periodontal disease and loose supporting teeth;
• there is no financial opportunity to install implants;
• too few teeth for locking clasp dentures.

The need to use this design is still determined by the doctor.

Telescopic crowns: manufacturing stages

The production of the design described in the article is possible today in two ways: stamping and casting. The first method is considered the simplest. However, when using casting it is possible to obtain a more attractive appearance product due to processing with modern materials.

The production of telescopic crowns begins with grinding the patient’s teeth to fit the inner part of the structure. The specialist then takes impressions and sends them to the laboratory. There, technicians are already making models based on them and making caps. It is very important to check the parallelism of the walls of the supporting teeth so that the structure fits accurately. After trying on the caps, a plaster cast is formed from them for casting future model. The external crown is made taking into account a gap of 0.5-1 mm. Based on the resulting impression, the external structure is already made.

Cost and service life

A telescopic crown is considered a relatively expensive pleasure. Its cost can vary from 5 to 11 thousand rubles. If we talk about complete prosthetics, the final price will depend on several factors simultaneously (material used, number of supporting teeth, etc.). It is not possible to name it exactly.

Telescopic crowns are characterized by a short service life - no more than 10 years. To increase it, you need to periodically visit a doctor and monitor the operation of the structure.