Application in construction sliding formwork made possible by the development of technology and equipment capabilities. The construction of buildings, when sliding formwork is used, has both its advantages and disadvantages, which are taken into account when choosing a technology before starting work.
Sliding formwork is a structure of two panels that are installed around the entire perimeter of the building. The shields are assembled into an integral structure, fastened together at a certain distance, on which the thickness of the poured wall will depend.
The panel structure acquires the necessary rigidity due to a special frame, which consists of two horizontally passing beams. The frame, in turn, is attached to the lifting mechanism, which ensures uniform and timely lifting of the entire structure.

Slipform construction is quite specific and requires many requirements to be met. This technology is most justified in the construction of several high-rise buildings, which are located next to each other. If there is a need to build a single building using sliding formwork, then it will be justified only if its height is more than 25 meters.
In most cases, this construction method is used for the construction of simple rooms or technological buildings. Since the construction of a building with monolithic casting complicates the organization of window and other technological openings, such construction is rarely applicable for the development of housing complexes.
Slipform casting is most commonly used for erection storage facilities, simple buildings, chimneys and other things. The use of this technology can significantly speed up the construction process. In addition, the monolithic structure, due to the absence of seams, has increased sound insulation properties and improved thermal insulation.

For building walls monolithic buildings Shield sliding formworks are used, which differ in the material from which they are made and in other technological nuances.
Formwork panels are assembled either from metal parts or from moisture-resistant wood. Inner part shields that come into contact with concrete are made of sheet steel. When assembling the panels, the need for the taper of the pouring structure is taken into account. In the calculations, the discrepancy between the distances between the upper and lower parts of the shields is taken to be about 0.5%.
The boards are assembled on the basis of the frame, which is the supporting link for the platforms, decks and necessary equipment... The entire structure is fixed on stackable rods, which are initially fixed to the elements embedded in the foundation of the building.
The structure is lifted with special jacks, which may differ in the type of drive. A manual lift drive is rarely used. Although this type of jack is the cheapest, it does not provide a high rate of construction, which is more important. Hydraulically and electrically powered jacks are more efficient.

Sliding formwork technology

When using sliding formwork, it is necessary to use high quality concrete mixes. To ensure a continuous pouring process, it is required to simultaneously ensure the timely solidification of concrete in the lower layers, and its liquid state in the upper.
The concrete is poured into the formwork continuously. Another layer concrete mix must be poured and tamped down before the previous one grasps. If, for any reason, an interruption of the process is required, then special additives are added to the mixture to slow down the solidification process.
Each subsequent layer of concrete is poured with the same thickness, which ranges from 10 to 20 centimeters. It is this thickness that allows the endurance of the technological process to be ensured.
If the walls of the building are erected in areas with a cold climate, then to ensure the continuity of the process, a piece heating of concrete is used. Heating concrete structure can be done by laying electrical heating cables or by using infrared heaters.
In addition to the continuously rising formwork, a step-by-step re-positioning of the structure can be applied. It consists in tearing off the panel structure from the frozen wall, followed by installation at the next level of the fill. In this case, the formwork constantly moves up and down with the same amplitude to prevent the boards from sticking to the concrete.

Before calculating the stairs, you need to consider the main types of these structures.

Simple staircase design: 1 - channel; 2 - corrugated metal steps; 3 - steel "filly"; 4 - welding places; 5 - step mounting brackets.

Straight stairs are the most simple form this design. It is convenient to navigate along it, including carrying heavy things. If the house has high ceilings and the ladder consists of more than 18 steps, then it is recommended to arrange an intermediate platform in the middle of the structure. The disadvantage of this type is the large occupied area.

Two-flight stairs have an intermediate platform and can be angular or U-shaped. Although this type is characterized by the presence of an intermediate platform, due to its configuration, the structure fits well into almost any room, including not so big size... In the U-shaped type, the width of the intermediate platform must be not 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, instead of intermediate platforms in which special rotary (winder) steps are used. Transient species require a minimum free space and fit easily into confined spaces... The disadvantage of this type is the complexity of the design, complex scheme stairs, since all winder steps are different, have their own individual sizes... And the stringers and railings are also distinguished by 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 less convenience when moving along it, a steep climb, and it is very difficult to lift heavy and bulky things along it. The spiral type is distinguished by its complexity of design, the calculation of the stairs is difficult, but they have an attractive and spectacular appearance.

This type of ladder, such as "samba" or "goose step" is also distinguished by its economical configuration. The main hallmark is a diagram of a ladder, namely half steps, which set the sequence of a step in strict adherence. Depending on the position of the first step, the ascent will always start from one specific leg (right or left). This type is distinguished by its steep climb. Most often, such a staircase scheme is used as an auxiliary one, for climbing to the attic, in extremely limited space.

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Calculation of stairs during design

If it is necessary to install a staircase in the house, then many issues will have to be resolved. And not only with regard to the type, materials, but also the need to calculate the stairs.

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

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

After that, the number of steps is calculated. For this, the height of the room must be divided by the desired step. Upon receipt fractional number the calculation of stairs requires an adjustment in the direction of decreasing or increasing the number of steps, according to which the step will increase or decrease.

Each ladder 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 tread value by the number of steps. It is also necessary to add 80 mm to the resulting number, technical dimension, i.e. the distance allotted for the lunge of the first stage and part of the upper module. When building a staircase, calculating its width, it is necessary to take into account the dimensions of the room, and how much space can be allocated for the structure device. The value is calculated according to the free area.

It is worth considering that if the staircase does not fit a little into the dimensions of the room, you can use one trick. If the thickness interfloor overlap 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 the dimensions of the opening play in the choice of design. If it is too small (for example, width - 700-900 mm, length - 1100-1600 mm), then only a "goose step" staircase can be entered into it.

Also, the diagram of the staircase, its shape depends on the desired step of raising the step and the width of the tread.

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

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Formulas for calculating stair elements

There are several formulas for calculating stairs that will allow you to design the correct structure.

Among them, 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, however, the following deviations are allowed: tread: 26 ≤ b ≤ 32 on average 29, riser: 14 ≤ a ≤ 20 on average 17.

The height of the rise 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 stairs to 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 should 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 one) and the length of the projection of the structure onto the floor plane l. The slope is calculated by the formula: k = h / l.

Now tourists often ask themselves what to take on a hike: a regular, proven foam foam or an innovative self-inflating rug? Some people do not understand why a whole "inflatable mattress" is needed during a hike (though there are almost no similarities to a mattress)? Others want to have at least some kind of comfort outside of civilization, even if it will be just something sleeping place, but what comfort does the traveler feel when using this wonderful 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, other foreign companies began to produce them, in particular: Tramp, Pinguin, Hannah, Terra incognita and our Russian Nova Tour.

The self-inflating mat is a two-layer construction. 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 unfolded. The enveloping material is closely connected to the filler, which, in turn, does not allow air to escape from this envelope, and does not allow water to be sucked in.

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

In total, these actions 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. In the event that you suddenly have little time, there is an opportunity to inflate the rug much faster, using a pump or, again, using your lungs.

A newly purchased self-inflating rug inflates much more slowly than a previously used one, and thinner items are also more difficult to inflate.

Shipping Questions

For transportation, the mat must be rolled out on the ground, then open the valve and roll it up as tightly as possible, gradually squeezing air out of the porous structure. Then you need to tighten the valve and place the rug in the cover.

Storage rules

Best of all, the mat is preserved and, at the same time, does not lose its properties, in the unfolded position and with the untwisted valve.

Or, not having such an opportunity, even if it is rolled up, but not tightly and, also, with an open valve, otherwise you risk getting a product unusable after improper storage (in a tightly rolled position with a closed valve, the mat may begin to delaminate). And most importantly, avoid rooms with high humidity, otherwise it will soon be necessary to dry the entire product.

Features of washing the thermarest

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

Consider the advantages and disadvantages of such rugs.

Perhaps, first of all, let's turn our removal to the advantages of self-inflating rugs.

The self-inflating mat has excellent heat retention so you are safe from hiking in winter time years, 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 warm bed, reminding you of home comfort... This is the quality for which such rugs are very much loved by travelers.

• It is also resistant to stress and pressure.
• Compact enough.

But still there is a downside, that is, drawbacks, now let's talk about them.
When handling rugs, it will be useful to remind you of accuracy, they are easily punctured. From this it follows that it is imperative that before spreading the thermarest on the ground, it is necessary to remove all fragments, thorns, branches, if any, from that place. V otherwise it can be damaged and it will no longer be inflated. And the best thing is to lay such a rug in a shelter, that is, in a tent.

Availability extraneous noise during use, similar to a cellophane bag. If these sounds are unpleasant to you, then it is better to refuse the self-inflating rug. Thermartests, unlike classic rugs, have more weight, and if you went on a hike light, it is better to give your preference to ordinary foam mat.

By the way, complete with such rugs always includes a repair kit for repairing the product. And if suddenly you still pierced your rug, then you must use this set. It contains glue and several rather large patches.

Choice

And now we will analyze the most important question, how to choose a self-inflating rug?

Most main criterion, by which thermarest is usually selected, this is the weight, which we have already mentioned above.

And here the main thing is not to make a mistake, it all depends on what time of year you buy a rug. In 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 is from 1.1 to 1.3 kg on average.

For other periods, you can choose options that are smaller in size, a mat with a thickness of 3.8 cm will do, its weight can range from 460 to 1000 grams.

More seasoned hikers caution that the most useless thermarest on a hike are those with a rubber jacket. Rubber, as you know, 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 self-inflating rugs are, by weight, what they are made of and what structure they have, as well as the pros and cons of thermarest.

It remains to mention how in no case should they be used. Do not use as a sled or inflatable mattress at sea, as well as in the role of a fan for a fire, it will not work either.

There are a few more points: you cannot inflate the product with a closed valve, otherwise, from overheating of the air from the inside, it can inflate and stick out at the seams. We hope that our tips will help you when choosing and using the miracle rugs.

Discussion: there is 1 comment

Interesting gadget, I think to take one for the next trip to the sea. And then in sleeping bag sleep is somehow not ice, age is evidently taking its toll)) I read all the pros and cons, I promise that I will not use the rug as a sledge or as a fan))

To answer

The device of a special electrical circuit with pass-through switches is a structure of two or more products interconnected electric wires and including itself lighting fixture... Outwardly, this version is no different from the standard one. The main distinctive feature the design of its contact group is protruding. Standard Models provide only the closing and opening of the electrical circuit. In this article we will look at the device, purpose and principle of operation. pass-through switch Sveta.

Operating principle

The basis of the functioning of the walk-through models is the switching of reverse electrical conductors. The principle of operation is as follows: when the position of the keys is changed, one circuit is opened, and, at the same time, another is closed. Having carefully studied the diagrams below, you can understand how the pass-through light switch works:

Because of such a contact arrangement, it would be more correct to call the pass-through switch a switch. However, since the term has been used for a long time, making formal changes can only lead to additional confusion. It can also be called crossover, crossover and duplicate.

Application area

The use of a pass-through switch allows the consumer to control both a single light source and a whole group of luminaires from a number of different locations. This means that the application is advisable in areas with a large area: at the stadium, in a large concert hall, tunnel, underpass, basement or in private multi-storey buildings with stairs and long corridors... Let us indicate, using an example from life, what this version is needed for.

The consumer, who goes up to the second floor of the house, turns on the lamp on the first floor, when using the pass-through switch, there is no need to go back down in order to turn it off. This allows the occupant to turn off the light from the second floor. We talked about this option for controlling the light in the article -.

Very often the switch is placed precisely in the corridor, or in a long span, hence it is called "checkpoint". Also, redundant devices can be used for control in any territories.

Varieties of models

• According to the type of wiring, models are distinguished for external and.
• Contact terminals inside the housing, depending on structural performance, can be performed with screw terminals, and can also be spring-loaded.
• Depending on the number of keys, switches are distinguished with one key, with two keys, as well as with three or more.

Design

What is a single-key pass-through switch and a multi-key device made of? A one-key fixture has three contacts; it includes one input terminal and two output terminals.

The device of a duplicate switch already with two keys is as follows: six contacts, that is, two input terminals and six output terminals; with three to nine: three input and six output terminals, and so on.

The symbol on the circuit of a conventional switch is a circle from which a branch of an L-shaped or T-shaped shape comes out. The L-shaped branch means that it is turned off in the open version, the T-shaped branch - in the hidden version. The number of branches means the number of keys.

Duplicate switches are depicted using the same shapes, however, to distinguish them from standard devices, L-shaped and T-shaped branches are applied from two opposite sides of the circle.

It is possible to use a pass-through switch in electrical diagrams as usual. As you know, these switches are intended to be used in pairs. If you start to operate it without a pair, then it can serve as a regular switch, simply interrupting the circuit and turning off the light. However, in this case, the expediency and the very essence of the use of this particular type of performance are lost, because main feature pass-through switches is their very principle of operation based on switching.

There is also such a method of controlling light sources as wireless light switching. A special remote control is used to control the light. The remote control allows switching off / on using a radio signal, directing it to a control relay connected to the lighting device. This activity requires installation power unit, which receives the control command. The block is placed next to a light source, or in places where wires fit to it.

So we examined the device, the principle of operation and the purpose of the pass-through light switches. We hope the information provided was useful and interesting for you!

Continuous presses. They are widely used due to the possibility of pressing in a thin layer, high productivity and less labor cost.

Belt press SH10-KPE is designed to squeeze juice from fruit and berry pulp.

The press (Fig. 1) consists of pressing conveyors 8, a feeder 4, a deflecting drum 7, a frame 3, a tension drum 1, a mechanism 2 for cleaning and washing, a pressure device 6, a belt 5.

Pressing conveyors are a structure of two necks, interconnected by supports and welded from channels, and serve to squeeze juice. On the bottom of them there are guides along which the chain slides. The pressing conveyors are mounted one above the other in such a way that the gap between them is constantly reduced, due to which the juice is squeezed out.

A twin-screw feeder with a perforated body serves to feed the pulp, the deflecting drums are the supports of the fabric filter belt. The tension drum is designed to stretch the filter belt. The mechanism for cleaning and washing is made in the form of a rotating brush and a tubular device for supplying water.

Rice. 1. Belt press SH10-KPE

The crushed mass is fed by a screw feeder inside the filter cloth, which is pre-rolled into a sleeve around the feeder body. The sleeve with the pulp is picked up by pressing conveyors. The squeezed juice flows between the slats along the surface of the conveyor and is fed into the collector. After leaving the pressing zone, the fabric is unrolled into a flat belt using a special device and the pomace is unloaded. Then the fabric is cleaned, washed and returned to the pulp loading area.

Technical specifications belt press SH10-KPE: apple productivity 3000 ... 5000 kg / h; water consumption 6.0 m 3 / h; speed of pressing conveyors 0.04 ... 0.12 m / s; installed power 28.4 kW; overall dimensions 6870x2985x2570 mm; weight 15170 kg.

Belt press PL (Bulgaria) is designed to produce apple juice and consists of an endless filtering web that runs between two vertically installed metal plate belts and two rows of vertically placed plastic rollers. The belts move in opposite directions at an angle to one another (Table 1).

The pulp is pumped into a bent filter cloth and first passes between the rollers, then enters the space between the pressing plate belts, where it is subjected to increasing pressure. The juice, flowing down the surface of the belts, is collected in the lower collector.

The strips supporting the filtering cloth diverge at the exit from the press, and the cloth is opened, the squeezes are thrown away. Next, the canvas is cleaned of residues of pomace and washed with water.

Belt press PVK-12 (Yugoslavia) consists (Fig. 2) of a supporting frame 9, a receiving hopper 2 for pulp, two endless mesh belts 3 made of polyester, which move around sixteen rollers 7 of a special design, a collection tank 6 for juice, a drive with variator 8, tensioner 4, mechanical-pneumatic device 5 for tensioning the belt and the system 1 for washing the belts.

Rice. 2. Belt press PVK-12

The pulp is fed from the hopper onto a belt, which initially runs horizontally. In this section, gravity juice is separated and the pulp is compacted into a "cake", which moves further between the stretched belts and a cascade of rollers that create pressure on the pulp and squeeze the juice. At the end of the press, the belts diverge, the "cake" falls onto the waste conveyor. The belts, returning to the place of loading, are washed with water along the way. The speed of movement of the belts and the thickness of the mash layer on them are regulated.

Apple productivity 12 t / h; installed power 3 kW; water consumption 2 m 3 / h.

Belt press "Klein" type FP (Germany) - the most advanced press of this type. It is equipped with longer belts, on the working section of which there are four zones (Fig. 3).

The press consists of a loading hopper 1, control drums 2, drive rollers 3, a device 6 for washing the belt and tension rollers 9. The press has four pressure zones: 8 - drainage, 7 - medium pressure, 5 - shear and 4 - high pressure.

The pulp is loaded into the press by a screw device that adjusts the width and height of the pulp layer on the belt. The pulp distributed on the belt passes through the drainage zone 8, where up to 20% of the juice is separated - gravity, then in the medium pressure zone 7 the pulp is squeezed between two belts and about 30% of the juice is released from it.

Rice. 3. Belt press "Klein" type FP

Further, the partially pressed pulp enters the shearing zone 5, where it passes around eleven pressing rollers with successively decreasing diameters, of which the first three are perforated. When moving on rollers, the layers of pulp adjacent to the upper and lower belts are shifted (cut) one relative to the other, so the juice is released from both the upper and lower layers. In this zone, up to 40% of the juice is released. In the high pressure zone 4, a further 10% of the juice is separated. The pressed pomace is removed from the belts using a self-steering tilting scraper, which are then washed with water jets from flat nozzles.

The presses are of three types: FP-1, FP-1.5 and FP-2 with a capacity of 4, 7, 6 ... 14 and 8 ... 20 t / h, respectively; belt width 1; 1.5 and 2 m; yield of juice from apples 75 ... 82%; length and height of all types of presses, respectively 4.2 and 2.5 m, width 1.6; 2.5 and 2.8 m.

The screw press VPND-10 (Fig. 4) is designed to squeeze juice from grapes. The basis of the press is a welded frame 1 made of structural shapes. It contains a perforated cylinder 5 with bandages 6, a cast hopper 4, a special gear reducer 3, a drive motor 2, a locking housing 8, a thrust bracket 9 and a hydraulic regulator 10. Inside the perforated cylinder there are 15 conveying and 12 pressing screws.

The pressing auger has a variable diameter and pitch. Towards the exit to the bale chamber, the diameter of the screw base increases and the pitch decreases. In this case, the volume of the pressed mass decreases, and the pressure increases, which is what is achieved required degree compressing the pulp in the press. The main shaft 18 passes inside the screws, by which the pressing screw is driven in rotation in the direction opposite to the rotation of the conveying screw, and with a different frequency. Rotation is communicated to the conveying auger from the hub of the gear wheel of the reducer. From the outer upper side, the perforated cylinder is closed by a casing 7, in the lower part of the cylinder there is a collector 14 with two outlets 13 of pressed juice. The receiving hopper is equipped with a 17 collector with a 16 outlet. A pressure gauge 11 is used to control the pressure in the hydraulic system.

The pulp (crushed and whole berries without ridges) is loaded into the press hopper, where a part of the gravity juice is separated from it. Then the pulp is captured by the turns of the conveying auger and moves into the cylinder towards the pressing auger. At the junction of the augers, the pulp is loosened, which facilitates further extraction of the juice. The joint cavity of the augers resists the backward movement of the pulp into the receiving hopper and creates conditions for the normal operation of the pressing auger. The partially dewatered pulp is compressed by the pressing screw and fed into the pressure chamber, where it is subjected to maximum compression. The squeezed out dewatered pulp then enters the annular channel between the perforated cylinder and the closing cone 8 and is removed from the press. The squeezed juice is collected in a collector 14. The degree of squeezing out the mash in the press depends on the size of the annular gap, which is regulated by a hydraulic locking device.

Rice. 4. Screw press VPND-10

The screw press VG10-20A (Fig. 5) is designed to squeeze juice from grapes. The basis of the press is a frame 1 welded from shaped rolled metal. The main body part 13 is mounted on it, to which a hopper 14 is attached to the top for receiving the mass, and from the bottom - a collector 2 for juice (wort) of the first fraction. To the flange of the main body part is attached the main perforated drum 19 with shroud rings of stiffness 18. Inside the drum, along its axis, there are two screws: transporting 3 and pressing 16. The screws are mounted on the shaft 26, and the pressing screw is rigidly connected to the shaft and the torque is transmitted to him with keys 17, the transport auger is loosely seated on the shaft. The shaft receives rotation from the electric motor 8 through a V-belt drive 10, a standard gear reducer 7 and a gear pair 5. Rotation is communicated to the conveying auger from the same drive through a chain drive 12 with a tension sprocket 4. The main shaft is installed in bearings 6 and 11, the housings of which are attached to frame. At the end of the main perforated drum there is a locking cone 20, which regulates the area of ​​the annular opening for the outlet of the pressed mass and, consequently, the moisture content of the pomace. The movement of the cone along the axis is provided by a hydraulic drive consisting of a pump 23 and two cylinders 22. The oil pump is mounted on a bracket 24 attached to the frame. A maximum pressure chamber is formed between the last turn of the pressing screw and the shut-off cone. Inside it there is a small perforated drum 27 with a cover 21 for sanitizing and a nozzle 25 for removing the wort.

Rice. 5. Screw press VPO-20A

Under the main perforated drum is a collector 28 for the wort of the second and third fractions.

The press drive is closed by a casing 9, and the main perforated drum is closed by a double-leaf casing 15.

The rotational speed of the main shaft with the pressing auger is 3.5 min-1, the conveying auger is 7.5 min-1 in the opposite direction, which ensures the movement of the pressed mass and a high yield of juice.

During the operation of the press, grape berries separated from the ridges, partially destroyed in crushers-ridges, enter the press bunker. Here the pulp (pulp) is captured by the conveying auger and fed to the pressing auger. In the section of the conveyor screw, the juice (wort) is partially separated from the mash and collected, it is of the highest quality, since it contains a minimum amount of suspended particles.

At the junction of the augers, the mass moves, that is, it undergoes shear deformations, which ensures the formation of a good drainage system of channels in the pulp for removing the wort.

The industry produces presses VPO-ZOA and VPO-50, similar in design (Table 2).

The screw press РЗ-ВП2-Ш-5 of the modernized design (Fig. 6) is used to obtain apple juice.

The press consists of a frame 4, on which a perforated cylinder 10 is mounted. Inside it, there are 8 conveying and 11 pressing screws, a hopper 7, a body 3 with obturators 2, a perforated chute 6, pallets 5 of the hopper and 9 cylinders, a locking cone 13 with a drum 12. The pressing auger is fixed on the shaft 7. There are shields inside the body: left 14 and right 15.

Thanks to the use of a wire filter cylinder with fine perforations, open obturators in the housing and an intermediate support of the main shaft, the technical and operational parameters of the press have increased.

Rice. 6. Screw press RZ-VP2-Sh-5

The productivity of the press has significantly stabilized during the processing of apples, both at the technical stage of maturity with elastic fiber, and those that were stored for a long time or overripe.

In the new press, 1.5 times more gravity juice is released from the bunker zone.

Owing to the use of open occluding devices in the body of the new RZ-VP2-Sh-5 press, the conditions for the grabbing of the pulp by the auger are facilitated; therefore, there were no cases of pressing the pulp during operational tests during the entire processing season. As a result of the use of an intermediate support located in the perforated cylinder of the press, a guaranteed gap between the screw and the cylinder is provided, the possibility of friction between them is eliminated, and the reliability of their operation is increased.

Technical characteristics of the press РЗ-ВП2-Ш-5: productivity for apples 5000 kg / h; juice yield 71%; power consumption 4.5 kWh; outer diameter of screws 520 mm; overall dimensions 4600x1000x1700 mm; weight 3500 kg.

It should be noted that the quality of apple juice obtained on screw presses is lower than the quality of juice pressed on bag or belt presses.

Pulse auger presses with periodic rotation of the auger and its subsequent longitudinal movement have become widespread, which allows pressing with minimal abrasion of the pulp.

Calculation of screw presses is carried out as follows. The media to be pressed, which have a significant ultimate shear stress, move in the press channels in the form of a solid solid, experiencing friction against the screw and cylinder. With this movement, the change in pressure along the channel can be approximately determined by the formula