Special machines used in wine-growing

10.1 Mechanization of green work

The supply of the appropriate amount of sun light depends not only on the weather conditions at the location of the grape-vines, but to a significant extent also on the arrangement of the local surroundings, the height and condition of the canopy, and the types and method of green work to be performed. Optimal assimilation rate can be expected only if the canopy has sufficient exposure to sun light and appropriate air flow within the canopy is ensured. Therefore, during the vegetation period, the shoots of the grape-vines must be regulated. Green work includes trunk cleaning, tying, trunk topping or heading, and partial defoliation within the cluster zones. (Walg 2005)

10.1.1 Trunk cleaning machines

Green work starts with trunk cleaning, that is the removal of offshoots and water sprouts. This task begins when the offshoots are no longer than 10-15cm, thus, they may still be removed without causing greater injuries. Instead of manual work, trunk cleaning machines can also perform the task on the trunk’s lower and middle part.

The first types of trunk cleaners cleaned the trunks with the help of narrow rubber strips fixed to a vertical, rotating axle breaking off water sprouts during rotation (Figure 10.1). In the course of this process, the trunk cleaner is not guided in the neighborhood of the vine-stock’s head, but along the trunk, permitting the machine to oscillate a few centimeters. The rubber strips attached to one or two axles make adjustment to the various trunk heights possible. The trunks must be straight and at least 70cm high. Optimal work capacity is achieved if the row distance is at least 1.8m.

In order to decrease dust formation, trunk cleaning should be done when the soil is wet (for example, in the mornings, when dew is falling). In addition, the equipment should not be close to the soil surface but slightly above it. Trunk injuries cannot be avoided completely during the trunk cleaner’s operation. However, the extent of these injuries can be favorably influenced by regulating the number of revolution per minute and the travel speed.

Tractor-mounted trunk cleaners can be placed ”under-belly” (that is under the belly of the tractor) between the front and back axles or before the front axle or in the back. In practice, these machines are mostly used at the same time as other row-bottom cultivation work is carried out and are mounted on the two sides of the cultivator or the mulcher. The equipment may also come with guiding rollers.

Figure 10.1 Trunk cleaners

10.1.2 Binders

The term „binding” means the elevation and stabilization of summer shoots in order to ensure that they are erect and do not hang over the row. This work is carried out mostly manually. The shoots are slipped in between wires (shoot threading) and the wires are stapled together. Grape-vines must be tied two or three times a season. As binding is primarily a factor of time, vineyards are especially interested in decreasing the utilization of manpower in this work.

In order to decrease work peaks, in many vineyards, automatic binding machines are used. Currently, there are two different approaches. First, the machines do the binding with plastic cords (for example, ERO). The machines pull the cords together and clasp the canopy (Figure 10.2). Second, the binding machines lift the previously released wires and staple them together at the required height (Pellenc).

The binders are suspended in front of the tractor’s front axle so that they arch over the row to be tied. Two electric or hydraulic driven spiral conveyers, belts or elevating discs pull up and hold the shoots. Simultaneously, on the right and left sides of the row, a plastic binding wire is pulled off a reel through a guiding ring, which, as a result of a light braking force, becomes taut. From here, the wire runs under the tying gaps of the automatic stapler, where the staples are released manually. They grab the canopy through the gaps and staple the two cords together. Stapling is necessary, since it provides the canopy with strength and prevents the shoots from slipping down. For each trunk, two or three staples are placed lengthwise.

Figure 10.2 ERO spiral tying machine

The Pellenc system functions without binding wires. In this case, fingered discs lift the wires already on the ground to the required height, pull them tight and clasp them together with plastic staples (Figure 10.3) in pairs. This is the reason for the wires having to be laid on the ground before tying. Generally, two staples are used for each post. The binding machines are mounted on a hydraulic elevator mechanism, and can be shifted both vertically and sideways. They can tilt and swing so as to adjust to the field condition of the plantation. The machines may be equipped with rotating knives for the purpose of cutting off the ends of the shoots.

Figure 10.3 Pellenc tying machine

10.1.3 Trimmers

If the shoots grow above the top wire significantly, the part reaching above the wire is removed or headed. Later on, also those shoots which grow sideways out from the trellis are removed. The two tasks may be performed simultaneously. The following goals may be achieved by trunk topping:

• the canopy will not hinder summer soil cultivation and plant protecting work,

• the canopy will aerate better and dry out quicker, with which the risk of mould can be decreased, and

• the storing of sugar in the grapes can be facilitated.

Today, this work can be fully mechanized and trunk tractor mounted trimmers are available also on sloping areas. According to their operational principles, there are machines equipped with rotating knives and mower..

Trimmers consist of the following main structural elements:

• Tractor-mounted frame,

• Elevator and turning mechanism, and

• Cutting equipment supplied with driving implements.

Hydro-motors mounted on the tractor’s hydraulic system drive the cutting equipment. The knives can be driven simultaneously with the help of V belts or flat belts. The machines can be tilted; the height and width of the cutting mechanism may be adjusted hydraulically or electrically. They can be mounted on the front of the tractor or on its back. For better visibility, the trunk topping machines are almost always mounted on the front of the tractor. They come in the following versions (Figure 10.4):

Figure 10.4 Trunk topping machines in different arrangements

In wine-growing practice, those approaches are increasingly favored where the machines arch over the rows. This approach is especially advantageous on plantations where cover plants are grown only in every second row, because this enables moving ahead on the grassed surface while cutting. The circumferential speed of the knives is 30-40m/s, accordingly, the rpm of the driving shaft is 750-1,500 min^-1. Cutting knives with a lower rpm cut with counter blade, while knives with a higher rpm cut without it. The tractor’s travel speed must be synchronized with the cutting’s the quality, which is usually 3-4km/h.

Figure 10.5 shows the sketch of the cutting equipment with rotating knives. The upper knives of the machine mounted on the front of the tractor cultivating on the two sides of the row are individually driven by a hydraulic motor, while the knives on the side are operated via a joint motor with a chain or tined belt. The mounting of the rotating knives may be varied and the holding mechanism may be adjusted sideways or upwards in accordance with the row distance. For example, when cutting grape-vines, it can operate on a plantation with a row distance of 2.4-4 m. In case of sloping up to an angle of 6 º, a separate hydraulic cylinder adjusts the axles of the rotating knives to the required position.

Figure 10.5 Trunk topping machine with rotating knives

On more modern machines, instead of using mechanical drive, the knives are driven by an individual electric motor. Electric motors receive current from a 4 kW, direct or alternating current generator driven via the power axle. These motors may be adjusted more subtly than those driven mechanically.

Another approach is to use mower blades fixed to a rotating disc, which are driven at the bottom by a joint hydraulic motor with the assistance of V belts. Where belts are used instead of discs, the blades are clinched or screwed directly onto the belt. This equipment is also placed on the tractor’s front and the rotating elements are covered by plate casing. The front part of the plate casing is tined. These tines serve also as counter-blades. Figure 10.6 shows a trimmer

machine with rotating knives driven by a hydro motor, arranged in the so-called walking stick style.

Figure 10.6 Walking stick style trunk topping machine

Trimmers with rotating knives are efficient even in case of a dense canopy. Hardly any cut-off plant remains on the canopy and the removed, well-chopped green parts do not clog up the cultivators. Their disadvantage is that they blow the cut-off plant parts in the direction of the tractor’s operator and, if the tractor moves in a too dense cluster, the flying material may damage some of the grape bunches.

Machines with rotating knives may be supplemented with various mower systems, for example, the cross-directional mower with knives rotating on a vertical plane or the vertical mower equipment, but there are also machines working with mowers only. The advantages and disadvantages of the individual operating systems may be partially balanced by using these various machine combinations.

The cutting mechanism of machines equipped with a mower consists of a beam similar to that of the mowers used for cutting grass. Machines with mowers are usually sold as reciprocating-motion equipment. They operate on the same principle as alternating mowers.

Trimmers with mowers (Figure 10.7) leave a clean and smooth cutting surface and do not blow cut-off foliage in the direction of the tractor’s operator. In addition, in case of certain cultivation methods, their application enables also pre-pruning of the grape-vine. Their disadvantage is that if the canopy is dense fast cutting is not possible. As the canopy falls down in bundles, this may hinder cultivating and the row-bottom cleaning machines in their work. The alternating mows positioned crosswise may leave loose parts on the top of the canopy creating good breeding ground for botrytis.

Figure 10.7 Trunk topping machines with a scythe

10.1.4 Defoliation

The timing of this task influences the future appearance of diseases. If a small degree botrytis infection happens in the summer, partial defoliation is performed also directly before the last spraying (in the middle of August) when the freely hanging grape bunches get one more optimal spray cover. Thus, grapes injured because of the defoliator’s rotating knives may be protected from fungus infections also subsequently.

Based on their operational principle, the defoliating machines may be classified as pulsed-air or sucking-air defoliators.

In case of machines operating with the pulsed-air system, nozzles fixed to a rotating wheel radiates the air generated by a compressor (approximately 850m ³/h) to the cluster zone with high flow speed. The blowing air tears off the leaves sooner or later. The use of these machines is not wide spread primarily as a result of their high investment cost (Figure 10.8)

Figure 10.8 Pulsed-air defoliator

Machines operating with the sucking-air system are structurally simple and their price is more favorable. The air flow sucks the leaves to the machine’s working area where they are detached by the cutting mechanism (Figure 10.9). The separated and chopped leaves fall into the inter-rows. The simple sucking-air equipment was designed for cultivating one side only. Consequently, for the purposes of removing leaves on both sides, the machine must pass along the row one more time. (Walg 2005)

Figure 10.9 ERO defoliator

10.2 Tools and machines used in grape harvesting

Mechanized harvesting is used on flat areas, on wine grape and raisin plantations. Manual harvesting is performed for the purpose of harvesting table grapes and on steep, sloping areas with implements facilitating picking. In case of mechanized grape harvesting, the grape berries and the grape clusters are detached, cleaned, collected, and transported. In case of manual harvesting, the same tasks are performed except for cleaning, because during manual harvesting the clusters do not get soiled too much. In terms of the process of detaching berries and clusters, harvesting can be done in phases or continuously. Harvesting can be manual, partially mechanized and fully mechanized.

10.2.1 Manual and partially mechanized harvesting methods

Manual harvesting is performed in phases. The following tasks are carried out.

• The grape clusters are cut off and collected in picking crates,

• The picking crates are carried to the collecting container,

• The grapes are delivered from the plantation, and

• The grapes are transported to the processing plant.

In case of partially mechanized harvesting, machines moving in one row or arching over one or two rows accomplish the collection and delivery of the grape clusters.

The following is a list of collecting and transporting equipment moving in one row.

• Sliding plates,

• Picking sledges,

• Trailers, and

• Tractor carried containers.

In harvesting and picking grape clusters, special harvesting shears are used. They cut evenly and are especially long compared to traditional scissors. They are narrow and pointed. Primarily plastic buckets and small containers serve as picking bins. These are light and can be cleaned without much effort. As they can be easily stacked, space is spared. The full picking bins are manually delivered to the colleting containers, usually handed over several rows.

Delivery by sliding plates is applied in vineyards where the distance between the rows is less than 3m. The empty plastic crates are positioned along the axle of the row. After harvesting, the full crates are placed on a sliding plate which is capable of transporting 1.5-1.8 ton. The crates are emptied into dumper-trailers or trucks.

Picking sledges are used in table grape harvesting. The harvester pulls a picking sledge in the inter-row. The full sledges are left between the rows or in the line of the row, to be collected by using sliding plates or trailers.

For the purpose of transporting large quantities of grapes, the simplest delivery method is using dumper-trailers. In most plants, they use one-axle, two-axle or tandem-axle dumper-trailers. The dumper-trailer needs appropriate receiving area in the processing plant. In practice, tanks, or containers capable of tilting, made of corrosion-proof steel or plastic and equipped with a closed spiral pump have lived up to expectations.

In case of carried containers, the unit container or the small container is mounted on a hydraulic rear-loading ramp. The container is filled in the inter-row and, thereafter, removed from the inter-row (Figure 10.10). The full containers are emptied into the transportation vehicle with the help of the rear-loading ramp. The container can be emptied mechanically or hydraulically. If the processing plant and the plantation are close to each other, the containers may be transported directly to the processing plant. The container’s capacity is 0.5 – 1.2m³.

Figure 10.10 Container carried in the back

Organizing manual picking and mechanized transportation are rather difficult tasks, because the delivery of the harvested quantities must be synchronized with the rate of picking. Using containers permanently on location greatly facilitates this process. The 5.1m³ - volume container is made of corrosion-proof steel plate. The container has a flat-steel reinforcement hoop on its side, with 2-2 pins attached. The container can be lifted with the help of the pins. The containers can be transported by vehicles equipped with the appropriate hydraulic device or a trailer. The hydraulic device is designed to enable loading from the side or in the back. The containers are emptied hydraulically at the processing inlet. One container can carry 3.8-4 ton, and its transportation speed is 50 - 60km/h on built roads and 20 - 30km/h on earth roads. (Karai - Mészáros 1980). Figure 10.11 shows the tractor-towed approach.

Figure 10.11 Grape-transporting container trailer

Where harvesting machines are used, harvesting, transportation and the capacity of the processing plant must be optimally synchronized. Transportation and processing must be adjusted to the capacity of the harvesting machine. Mash transporters are also used for delivering grapes from the plantation to the processing plant.

Mash transporters facilitate crushing and depositing, their holding capacity is at least 4m³. This transporter consists of a cone shaped container narrowing toward the bottom, with a built-in, ex-center driven spiral pump. This is not sensitive to material other than grape (MOG) and is of the appropriate transport height. The harvested produce is forwarded to a pump with the help of a spiral conveyer placed at the bottom of the container. For final crushing, spring loaded crushing cylinders with adjustable gap distance are used. Manual cranks or grouting discs placed between the cylinders can change the gap distance of the crushing cylinders gradually.

Mash transporters supplied with an elevator mechanism are capable of filling up the wine-press or the destemmer-crusher directly. Consequently, they offer numerous possibilities in red or white wine making (Figure 10.12). The wine-presses can be filled directly with grape clusters. With making work of the destemmer easier, the transformation of the produce into red wine becomes also a less taxing job, because the grapes can get into the horizontally positioned equipment even without the assistance of pumps. When using mash transporters supplied with spiral conveyers or conveyer belts, if the wine-press or the destemmer-crusher to be filled is not directly under the vehicle a separate conveyer belt becomes necessary.

The concept of arching over several rows is based on the principle that the pickers put the harvested grapes on the delivery belt running above the plantation, from which the produce is moved onto the tractor-towed transporting vehicle moving inter-row. In our country, equipment built on this concept is not used for two reasons. First, even despite the equipment’s complicated structure, it does not offer significant economic benefits. Second, it was developed simultaneously with other, significantly more efficient machines harvesting continuously.

Figure 10.12 Grape transporting vehicle with elevator mechanism

10.2.2 Mechanized grape harvesting

Manufacturers and distributors recommend self-propelled, one-pass harvesting machines (grape combines) and towed harvesting equipment for mechanized grape harvesting.

Several factors influence the choice of the detaching mechanism and the extent of harvesting loss. In addition to the training and trellis system, for example, the size of the detaching force between the berry and the stem and their strength and flexibility play an important role. The leaf’s characteristics related to friction and flow, the cluster, and the individual grapes determine the design of the delivery system, the sorting and cleaning equipment. In judging the efficiency of the harvesting procedure, the energetic efficiency to be achieved must also be taken into account. In order to optimize the mechanical grape detaching procedure, one has to determine the size of the detaching force between the berry and the cluster depending on the degree of ripeness, taking into account the frequency and the amplitude of the swinging-shakers.

The more highly developed machines are the shaker-beaters which deliver the detaching force vertically or horizontally on the grape wall. They operate with relatively small detaching force and big amplitude. Detaching occurs, as in case of all other mechanic-dynamic harvesting procedures, as a result of mass force. The pulling, bending, alternating, and rotating forces arise between the cluster and the wine stock, and the berry and the stem. The shaker-beaters swinging horizontally are suitable for almost all types of training. Shakers causing swings so that the detaching force always acts in the direction of the stem of the berries damage the produce less.

Harvesting machines working mechanically are mostly self-propelled rather than towed or otherwise carried machines arching over the rows. To satisfy various harvesting conditions, their drive is non-gradual hydrostatic. Slope equalization increases their utilization. Cleaning and separating the produce from leaves and other plant parts are carried out with the help of slanted or flat sifters and blowing-air and sucking-air fans. The produce is stored temporarily either on the machine or the transporting vehicle moving beside it.

The harvesting machines operating pneumatically detach the grapes from the vine-stock by high speed blowing or sucking air.

On blowing-air machines, two wreaths each supplied with 8 nozzles rotate at 150 rpm along the canopy wall. The wreaths are placed opposite to each other but are shifted in relation to each other. The air flowing out of the wreaths blows the canopy in alternating directions, resulting in swings. The transportation of the produce is done mechanically.

Sucking-air machines do not need catching devices and can be used in all training and trellis systems. The detachment of the berries requires significant, approximately 120 m/s air speed. During picking and transportation a significant number of the individual grapes break. The breakage increases the portion of tannin and lees in the must leading to deteriorating wine quality. In produce exposed to huge quantities of air, the process of oxidation accelerates. If applying this procedure, first the production zone must be defoliated with chemicals or heat, because later on it will not be possible to remove the leaves.

In electric harvesting procedures, high-voltage alternating current is led into the plant through the clusters and the berry stems. The stems of the berries burn and the berries may be harvested without any injury suffered. Detachment must be carried out fast to protect wine quality and the plant. Using 10 kV requires careful, investment -intensive safety measures against electric shocks. (Moser 1984)

The harvested produce is emptied mostly into the container vehicles moving in the parallel row. Machines are rarely equipped with collecting containers.

Towed harvesting machines can be used also in mid-sized and bigger plants to avoid the utilization of contract labor in harvesting. When selecting the appropriate machine, important criteria are its weight and mass distribution, design, hooping, and axle drive, the collecting container’s size, and the delivery belt and the cleaning device systems (Figure 10.13). Compared to self-propelled machines, their disadvantages are the smaller maneuvering capability and the slower travel speed. The advantage of modern towed harvesting machines is that they can be used on slopes of up to 30%. The basic condition to their operation is a tractor with a towing power of at least 37kW (on slopes, 44-51kW). Today, all towed harvesting machines are equipped with hydraulic axle drive.

Self-propelled harvesting machines (Figure 10.14) come with all-wheel drive, are expensive, but their capacity is significant. They are equipped with 60-117 kW diesel engines. Compared to towed harvesting machines, the self-propelled types have greater area capacity, their container has bigger holding capacity, and the hydraulic all-wheel drive enables a travel speed which is optimal in terms of slope and other field conditions.

Under optimal conditions, the self-propelled harvesting machines can harvest 0.6–0.7 ha per hour.

Figure 10.13 Towed harvesting machine

Figure 10.14 Self-propelled harvesting machine

10.2.3 Design and operational principle of harvesting machines

In case of mechanical harvesting, almost all machines use the mechanic-dynamic swinging-shaking method where the machines cause the grape rows to swing. The berries and the clusters detach when the force resulting from the acceleration caused by the swings exceeds the holding power of the berries. In older versions, a pair of shakers with ex-center drive serves as the detaching device. They are equipped with 4-8 cylinder shape plastic beating stocks reinforced with fiber glass (Figure 10.15).

Figure 10.15 Operation of a detaching device with beating stocks

The shaker moves evenly on the horizontal plane. It swings the rows by beating them from both sides, thus detaching the grapes. The produce detaches primarily as the result of the swinging motion and not because of the beating. The number of swings of the detaching device is adjustable gradually between 350-550 beat per minute from the operator’s cab to take into account various conditions, especially the grape type and the ripeness of the produce. Good work quality may be achieved by changing the most important adjustment features of harvesting machines, namely the travel speed and the number of swings. Their downside is that at the free end of the beating stocks out-of-phase swings may occur. The design of newer shakers on the market since 1990 solved this problem. As the ends of the beating stocks are fixed with bearings and the stocks have a different shape, the out-of-phase swings have been almost fully eliminated (Figure 10.16).

Figure 10.16 Shaker with bearings at both ends (Pellenc)

As a result, harvesting has become extremely gentle on the produce. The following two systems have been in use:

• Beating stocks with bearings on both ends (for example, Braud, Pellenc), and

• Drop shape beating stocks stiffened along their operational length (for example, ERO, Gregoire).

The older versions may be also equipped with drop shape beating stocks. Both systems apply protective methods, as the piercing style penetration by the stocks prevents large indented areas on the rows. In addition, they operate with a lower beat number than the old versions. They better adjust to the row and have no uncontrolled out-of-phase swings. (Walg 2005) The produce shaken off is caught in bowls or scaled plates and delivered to the collecting containers on ribbed conveyer belts or bowl type transporters (Figure 10.17). For the purposes of removing leaves, stems or shoot parts, they use 2-4 fans equipped with brushing and chopping implements. The grapes are poured out of the containers by tilting the containers sideways or backwards. The produce is distributed by using containers with distribution spirals.

Figure 10.17 Main structural elements of grape harvesters

All self-propelled harvesting machines are hydraulically steered, with hydrostatic all-wheel drive. They are supplemented with a built-in slope equalizer, therefore, they are easily maneuverable and their operation is quite safe. The directional angle of the beats is mostly 90º.

Mainly electronic regulators and control mechanisms assist in improving performance and work quality. They adjust steering and height to the requirements of the harvesting unit. They also control slope equalization, wheel slippages, the engine, and the hydraulic equipment. On newly designed harvesting machines, the gradual adjustment of the shaking’s frequency has been supplemented with amplitude adjustment. Riper produce can thus be harvested carefully.

The new machines working with a gentle shaking technique remove only a few leaves. As a result, as in manual harvesting, only a small portion of MOG remains in the harvested produce.

Today, multi-functional handles guide the machine’s main function. The deck computer increases not only the number of the technical possibilities, but also allows the collection of operational data, facilitating data transfer between the various information technology devices. To improve the utilization of the machine, the computer automatically adjusts the height of the harvesting unit, accurately positions the machine according to the row distance, and sets the regulating and controlling devices and the anti-slipping mechanism. In order to ensure safe travel on sloping areas, the self-propelled, but also the other harvesting machines, can adjust to the requirements of uphill and downhill travel with the help of the front and back axles. Driving performance equalizing the continuously alternating wheel load on the front and back axles can improve application safety. Work on a slope of up to 40% is safe.

The air-conditioned cab has ergonomic benefits for the machine’s operator. As the cab is mounted on silent blocks, noise is decreased. The air-suspension spring loaded seat adjusted according to the weight of the operator and set in the most favorable position is used for health protection purposes. The average adjustment values of modern grape combines (Walg 2005) are set forth in the table below:

Control questions to Chapter 10

1. What is the primary task of the mechanization of green work and what are the related machines?

2. What is the reason for using trunk cleaners and what are their application methods?

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3. Summarize the theoretical solutions and operation of the binder machines!

.4. Characterize the equipment suitable for trunk topping or heading procedures with the help of a drawing!

5. What types of defoliating machines do you know and how do they operate?

6. Summarize the characteristics of the various grape harvesting procedures!

7. What types of mechanized procedures assist manual harvesting? Discuss the operation of the machines used in these procedures!

8. Summarize the operating characteristics of fully mechanized grape harvesting!

9. Describe the structural characteristics and operation of the self-propelled grape harvesting machines!

Bibliography