Ultrasonic Langevin emitter. Ultrasonic vibration system

Harvesting grapes in a timely manner is as important as properly growing sun-loving crops. Delay is unacceptable, since every day the losses amount to 2–3% or more if the harvesting is delayed and the berries begin to deteriorate. The harvest time is determined by the sugar content of the grapes - the sugar accumulation of the bunches should be maximum.

How to determine the time of harvest ripening

Agronomists recognize the time of vine ripening by two factors:

Physical ripening - harvesting begins after all the grapes have ripened.
Technical – the period is determined based on the requirements for wine products. Although the bunches may remain physically immature.

Grapes are considered ripe when several factors combine:

Rich shade of grapes.
Sugar content measurements with a hydrometer at intervals of 1 - 2 days show the desired value.
Control with a refractometer confirms the ripeness of the grapes.

It is preferable to use a hydrometer because it shows more accurate data.

Using a hydrometer, we determine the degree of ripeness of the grapes as follows:

From several bushes we cut brushes with a total weight of 3 - 4 kg.
We make juice from raw materials.
We examine the strained juice with a hydrometer, which shows the amount of sugar. We draw up a harvest plan based on comparative data. We calculate them by increasing the percentage.

If the number of rotten berries on the vine is steadily increasing, we harvest the grapes a little earlier, avoiding massive damage to the bunches.

Technical varieties

The harvest of technical varieties is harvested when the grapes ripen until the berries accumulate the required amount of sugar and acids. These indicators depend on the type of wine that will subsequently be prepared from the grapes. The same variety reaches technical maturity at different times, which depends on the purpose of using the crop.

It is preferable to collect technical varieties using a continuous method. But sometimes agronomists use selective harvesting if there are variety impurities or diseased bunches among valuable specimens. Thus, enterprises receive high-quality raw materials for the preparation of juices and fine wines.

Rules for harvesting table varieties

Table grapes are usually harvested at the stage of consumer ripeness. The sugar content of very early and early varieties should start at 12%. For other varieties, a value of 14% and higher is acceptable. The maturity of table varieties is assessed by taste and external characteristics. In laboratory conditions, the maturity of a culture is determined by chemical analysis.

It has been noticed that with increased sugar content, clusters of table varieties are preserved better. Due to the uneven ripening of the clusters, the harvest is harvested in 2–3 stages. Between cleanings take a break of 5 - 7 days. When removing the bunches, do not allow them to be damaged and the prune coating to be erased. The coating improves the presentation of fruits and protects them from rotting. During harvesting, the grape brush is held by the comb.

Increased accuracy in work is necessary if the grapes will be transported over long distances or will remain in storage for a long time. Under no circumstances should cut brushes be kept in the open sun or left in the rain. Containers filled with bunches should be immediately removed to a shaded area of the yard.

Principles of harvesting and storing grapes

In central Russia and other regions of the CIS, grapes begin to be harvested in August, when the fruits are well ripe. The degree of ripeness is determined not only using instruments, but also by taste. Juiciness and ripeness indicate the readiness of the raw material to be cut.

If you don't know when to pick grapes for wine, taste them. For light table drinks and white varieties, the berries should have noticeable sourness and a minimum of sweetness. But the grapes should not be too green, otherwise the wine will acquire a grassy aftertaste.

If the grapes are used for semi-sweet or dessert wine, the grapes should be harvested when the fruits have accumulated more sugar. In other words, they must become overripe. Some winemakers use dried fruits to give the drink a specific raisin taste.

How to properly harvest grapes? To keep the bunches well, they are cut in dry weather. There should be no rain or dew while working in the garden. It is advisable to cut the brushes before noon, then they will emit a more intense aroma.

When asked what is the best way to harvest grapes, agronomists answer that this should be done in several stages, focusing on the maturity of the bunches. The selective approach is more troublesome and time consuming. However, it is worth trying to get quality wine.

In general the process looks like this:

The brushes are carefully taken by the comb and cut with pruning shears, without touching the berries.
The harvested crop is carefully inspected.
High-quality raw materials are placed in wooden boxes measuring 40 x 60 x 20 or deep baskets with a capacity of 10 - 12 kg (the baskets are pre-covered inside with burlap).
The container is placed in the shade under a canopy.
For storage, grapes are placed in the refrigerator, placed in plastic bags, or in the basement.

It is convenient to store large quantities of grapes in boxes. The bottom of the container is sprinkled with hardwood sawdust. The thickness of the layer is 2 cm. The clusters are laid out on the sawdust in one layer and the raw materials are sprinkled with a thicker layer of shavings - 4 - 5 cm. The boxes are taken to the cellar, where the temperature is stable at +2 - 3°C.

This plant has many varieties that differ from each other not only in color, size, taste of berries, but also in terms of ripening. To fully enjoy the taste of the berries of this amazing plant or the aroma of wine, you should harvest the grapes on time. Let's talk about this in more detail.

When the grapes are harvested

Depending on the goals that you pursue regarding the use of grapes, a distinction is made between harvesting technical ripeness and consumer ripeness. Consumer maturity involves picking grapes at the moment when the berries of the plant are completely ready for fresh consumption:

The berries have a characteristic color for this variety.
We have accumulated enough sugar.
They emit a persistent aroma.

If you prefer to use grapes for further processing, then they must be collected at the technical ripeness stage. That is, the plant is almost ripe, but not yet so aromatic and sweet.

If you decide to pick grapes, it is also important to consider the following:

Collection should begin only in dry weather.
You must wait until the dew has completely disappeared.
If you are completely satisfied with the taste, aroma and color of the berries, then stock up on pruners or scissors and go ahead to harvest the grapes.

It is best to harvest grapes gradually, since not all berries ripen at the same time.

When is the best time to harvest grapes for wine?

Connoisseurs of this drink know that the aroma and taste of the drink depends on the quality of the grapes. In order for the wine to be of excellent quality, the following rules must be observed:

It is not recommended to pick grapes for wine immediately after rain.
It is not recommended to go harvesting in the morning when the dew has not yet disappeared or in the evening when it has already fallen.
It is not recommended to pick grapes in fog.
The grapes should be cut, not picked.
As is known. Fermentation occurs at a certain temperature, so the berries must be collected under this condition, that is, the midday heat in this case is not the right time.
It is recommended to harvest grapes in several stages as the berries ripen.

To make a good wine, the berries must be well ripe, but not overripe. There are many varieties of wine, and the grapes for its preparation can be harvested in the phase of either technical ripeness or consumer ripeness.

One of gardeners' favorite plants is grapes - one of the oldest plants on the planet. The vine and grapes are called a symbol of fertility, labor and peaceful life. When growing it, you want to get a rich harvest of juicy and tasty berries. To do this, you need to know when the grapes ripen and other important points.

What affects maturation?

Harvesting grapes is a responsible process. It must be approached with special trepidation. The vine comes to life in the spring at an air temperature of + 10 °C. At this time, active movement of fluid begins, which is called the crying of grapes. Next comes swelling and bud opening. The warmer the air, the faster the leaves will appear.

Then the grapes begin to bloom. This is a very important moment, although it does not last long. It is best when this happens in dry weather with a light breeze. The wind will ensure good pollination, there will be no need to carry out additional work. The timing of grape ripening depends on many factors, including:

air temperature;
soil temperature;
humidity;
warm;
sunlight;
soil fertilization;
good care;
treatment for diseases.

During the ripening period, you need to take good care of the soil; it should be moderately moist. It is recommended to fertilize. When clusters begin to form, the plant slows down its growth. This allows the berries to fill, the grape bush increases in volume and part of the vine below becomes woody. Fruits ripen more slowly when the air temperature is below 20 °C. Under such conditions, they will grow small, sour, or may not ripen at all.

A gardener can help the grapes by adding boron and potassium permanganate, partially pruning leaves and removing shoots. An important factor for the ripening of grapes is weather conditions. Even how the grapes are harvested matters. It is worth remembering about the normalization of plants. It is necessary to leave a minimum number of bunches. This will allow you to get a good and timely ripened harvest.

Timing depending on variety

Plants are divided into different groups depending on when the grapes are harvested. For early varieties, during ripening, one of the signs is the suspension of growth of young shoots, early formation and ripening of fruits. In the later ones, the opposite happens: first the young vine grows, and then the berries ripen. In order to provide themselves with a tasty delicacy for a long time, gardeners plant bushes with different ripening periods. Grapes can be divided into six types based on how many days the fruit takes to ripen.

Very early

Super early grape varieties are in demand in places where summers are short or not very warm. These varieties ripen in about 100 days. Popular among them are:

Olympics;
Timur;
Elegant.

These types of grapes are distinguished by ripening of berries exactly on time. Despite the name of the group, it is clear that they will not grow in a day. They can be collected as early as early August.

Very early

Very early varieties are most often grown in areas with harsh weather conditions. The choice is quite large, and the harvest is generous. These include fruitful frost-resistant grape varieties, for example, Crimean Pearl.

The period during which healthy treats will grow in your garden bed is 115 days.

Early

The early ones include species that have been proven over the years and produce good harvests in harsh climates. They are easy to care for and unpretentious. The ripeness of the berries is checked by color and taste. For example, the Yantar and Donetsk pearl varieties grow for about four months.

Early-middle

Early-middle grape varieties are found in the south. Beautiful large berries are a real boon for winegrowers and winemakers. These species are used for the production of table wines. They also ripen in about 135 days and tolerate cold well. Gardeners choose Russian Concord and Arcadia for growing in their summer cottages.

Average

Medium varieties are most grown in those places where industrial berry processing plants have been built. Their collection dates fall at the end of August - beginning of September. Very tasty berries of the Muscat Odessa and Startovy varieties. Many of them are well stored and suitable for transportation.

Late

Late ripening grapes include grapes that ripen for five months. It gives a high yield and is well stored. It is grown more in places where warm weather prevails over cold. If unexpected cold weather sets in, a small number of bunches will still have to be cut off.

Do not regret the lost fruits, you can get a generous harvest. A very late grape variety ripens within 165–170 days. The grape harvest is carried out in October, or even in early November. You can store it in the refrigerator until December and it will not lose its appearance and taste.

Harvest

Grapes become truly tasty and healing when they are completely ripe. At this point you can begin harvesting. Grapes of dark varieties have a dark blue color when ripe, but if most of the berries are brown, this tells us that the berries are not ripe. White grape varieties have ripe berries that are amber or golden in color, while unripe ones have a dirty green appearance.

It is also important to note that bunches of grapes that are fully ripe are darker at the junction with the shoot, the berry softly comes off the tail, is fragrant and sweet. When cutting bunches of grapes, it is very important not to erase the coating that covers the berries, since removing it causes the fruit to deteriorate faster.

Early varieties ripen faster and are not stored for long, so they need to be sold immediately after harvest.

Middle and late species can be stored on bushes for a long time. Grapes should be harvested in dry weather, best in the morning without dew or in the evening, and in no case after rain. For storage, use a spacious room, place the bunches in boxes or hang them by their tails.

Video “Summer pruning of grapes”

From this video you will learn how to properly prune grapes in summer.

The property of ultrasonic waves to be reflected from an obstacle and return back in the form of an echo is used to determine the distance to hard-to-reach objects.

The mechanical sources of ultrasonic waves known at the beginning of the twentieth century - tuning forks and oscillating steel rods - had great power, but were not capable of sending them in a narrow directed beam, like a light beam. The ultrasound they emitted diverged in different directions. Because of this, it was impossible to determine the direction in which the object under study was located.

But the French scientist Paul Langevin found a way out. In 1916, during World War I, he was looking for a way to detect submarines using ultrasound. And as a source of ultrasonic waves, he used the piezoelectric phenomenon, which had not been used before.

Discovery of Piezoelectricity

Click on the picture

Piezoelectric effect was discovered in 1880 by French scientific brothers Pierre and Paul Curie while studying the properties of crystals. By compressing a quartz crystal from both sides, they discovered the appearance of electrical charges on the faces perpendicular to the direction of compression. The charges on one side were positive, and on the other - negative. They observed the same picture when crystals were stretched. On the face where positive charges appeared during compression, negative charges appeared during tension, and vice versa.

Pierre Curie

It turned out that in addition to quartz, crystals of tourmaline, Rochelle salt, lithium sulfate, and other crystals that lack a center of symmetry have similar properties. This phenomenon was called piezoelectricity, from the Greek word “piezo” - I press, and crystals with such properties - piezoelectrics.

With further research, the Curie brothers found that there is reverse piezoelectric effect. If you create electric charges of different polarities on the edges of a crystal, it will shrink or stretch.

It was this discovery that Paul Langevin used in his research.

Piezoelectric Langevin emitter

Paul Langevin

If a quartz plate is subjected to mechanical stress, it becomes electrified. And vice versa, if you change the electric field in which it is located with a certain frequency, then it will begin to oscillate with the same frequency.

What happens if you use electricity from a high-frequency alternating current source to charge the crystal? Having carried out such an experiment, Langevin was convinced that the oscillation frequency of the crystal was the same as the frequency of the voltage change. If it is below 20,000 Hz, the crystal becomes a sound source, and if it is higher, it will emit ultrasonic waves.

But the power of ultrasound emitted by one crystal plate is very small. Therefore, the scientist created a mosaic layer from quartz plates and placed it between two steel plates, which served as electrodes. To increase the amplitude of oscillations, the phenomenon of resonance was used. If the frequency of the alternating voltage supplied to the piezoelectric crystal coincided with its natural frequency, then the amplitude of its oscillations increased sharply.

This design was called the “Langevin sandwich.” And it turned out to be very successful. The radiation power was quite high, and the wave beam turned out to be narrowly directed.

Later, barium titanate ceramics, the piezoelectric effect of which is many times higher than that of quartz, began to be used as a piezoelectric element instead of quartz plates.

A piezoelectric plate can also be a sound receiver. If a sound wave meets it on its way, the plate will begin to oscillate with the frequency of the sound source. Electric charges will appear on its edges. The energy of sound vibrations is converted into the energy of electrical vibrations, which are captured by the receiver.