Tag Archives: hops

450–459 M. Krupička and A. Rybka
New design of roller separation line and its effect on the separation of hop matter
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New design of roller separation line and its effect on the separation of hop matter

M. Krupička* and A. Rybka

Czech University of Life Sciences Prague, Faculty of Engineering, Department of
Agricultural Machines, Kamýcká 129, CZ165 21 Praha 9 - Suchdol, Czech Republic
*Correspondence: krupicka@tf.czu.cz

Abstract:

This article deals with the roller conveyor which constitutes a part of a machine line to separate the hops harvested from low trellises. Various parameters affecting the right operation of this roller conveyor are examined. In the last season a model of roller conveyor designed and constructed for this purpose was subject to experimental verification with the objective of integrating it in the actual line. Dependency of hop matter falling through on the gap size between rollers was examined. They were standard, commonly used rollers.
In 2015 rollers with a different diameter and different profile of metal welded collars were designed and produced. The new construction allows for reducing the gap between rollers up to 20 mm. As compared to the former solution including rollers of 60 mm in diameter, this one constitutes a difference of 28 mm.
The measurements in the season of 2015 were conducted using these new rollers and there were two parameters to examine. They were the gap size between rollers and rotation frequency of the rollers. The measurements were carried out using a hop matter sample taken from low trellises. The dependency of the hop matter falling through was being examined for 3 gaps (28, 24 and 20 mm) between rollers and for three rotation frequencies of the rollers. The measurements revealed that with a setting resulting in the smallest possible gap between rollers (20 mm) by up to 15% more leaves can be separated, compared to the rollers of 80 mm in diameter, and by approx. 60% more leaves compared to the former solution including the rollers of 60 mm in diameter. Furthermore it was found that a change in

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101-108 M. Krupička and A. Rybka
Dependency of hop material fall through on the size of gaps between rollers of the roller conveyor in separating machine
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Dependency of hop material fall through on the size of gaps between rollers of the roller conveyor in separating machine

M. Krupička* and A. Rybka

Czech University of Life Sciences Prague, Faculty of Engineering, Department of Agricultural Machines, Kamýcká 129, 165 21, Praha 9 - Suchdol, Czech Republic; *Correspondence: krupicka@tf.czu.cz

Abstract:

This paper deals with a roller conveyor which forms a part of the separating machine for hops harvested from low trellises. One of the parameters that influences the correct operation of this conveyor is tested, namely the gap between the rollers. The aim of the test was to discover whether the fact that hop matter falls through the rollers depends on the size of the gap between the rollers. For testing purposes a model of the roller conveyor was designed, made, and subsequently tested in a series of experiments with the purpose of integrating it into a separating machine. The measurements were carried out using a sample of hop matter harvested from low trellises. The dependency of falling matter upon the gaps was determined in view of eight gaps between the rollers. The measurements revealed that the gap size has an influence on the falling of hop cones and small-sized admixtures only if the gap size is larger than the size of the hop cones. At the same time, this parameter has no substantial influence on the separation of medium-length and long stems which were separated perfectly.

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73-80 D. Hoffmann, A. Rybka, M. Linda and M. Kříž
Detection of anchoring columns in low trellis
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Detection of anchoring columns in low trellis

D. Hoffmann*, A. Rybka, M. Linda and M. Kříž

Czech University of Life Sciences Prague, Faculty of Engineering, Kamýcká 129, 16521 Prague 6 – Suchdol, Czech Republic; *Correspondence: dhoffmann@tf.czu.cz

Abstract:

Low trellis of hop field was emerged in the Czech Republic in the mid-nineties of the 20th century. Growing hops in a low trellis has already been tested in 1991 by Hop Research Institute Ltd. in Žatec. However, at that time, the lack of adequate (the dwarf) varieties and special techniques prevent to their expansion. For full use low trellis is necessary mechanization, that is already currently being developed. The main advantage of growing hops at low trellis is costs reduce. Some experts say cost reduction to 50%. Cost reduction is the result of simplifying the spring and harvest work (using a mobile harvester). Currently, a prototype of a mechanical cutter is tested in field conditions. Activity of mechanical cutter is now controlled directly by the tractor driver. This control of mechanical cutter (or rather inter-axle carrier on which it is cutter mounted) puts on the tractor driver too high demands on precision. Failure to comply with the conditions set comes in contact the trimming disc with anchor pillar and the mutual damage. The movement of inter-axle carrier would therefore be appropriate automatically. But at first, it is necessary to solve recognition (detection) anchoring columns of the low trellis. During the cutting of hops needed to ensure the most accurate copy of the columns by the trimming disc, to be trimmed hop vines and hops growing in close proximity (distance hops from the anchoring column is about 150 mm). The paper presents several types of sensors and describes their advantages and disadvantages. For laboratory test was developed model low trellis comprising also hop vine, at which were referred sensors tested. This article analyzes the measured results of individual sensors and it is shown, that not all sensors are suitable for this field application. In conclusion are recommendations for follow-up research.

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197-204 L. Vent and A. Rybka
Storage technologies of picked hops during harvest
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Storage technologies of picked hops during harvest

L. Vent* and A. Rybka

Czech University of Life Sciences Prague, Faculty of Engineering, Kamýcká 129, Praha 6 – Suchdol, Postcode 16521, Czech Republic; *Correspondence: lvent@tf.czu.cz

Abstract:

To prevent interrupting the process of drying or picking due to lack or surplus of hops coming out of picking line, in most cases there is placed a storage container as a capacity equipment. In a container, however, hops are layered, thus temperature and relative humidity increase owing to an increased intensity of hop cones breathing and an insufficient airing, i.e. they mowburn. In the process of breathing a cone loses important substances which results in its worse quality and correspondingly in worse quality of the final product. This work builds on research from 2011. There were monitored changes of physical characteristic of picked hops during storage in container and compared with control variant. This aim of this work is to compare different storage technologies of picked hop in the container. There was a three variants. The control variant was a common stack with a perforated bottom. The second variant was a stack with active ventilation by electric fan. The third variant was a covered stack with passive air circulation. Al stacks had one cubic volume. Data of temperature and relative humidity were continually recorded by MINIKIN TH measuring equipment by EMS Brno company. Another analogue sensors to measure relative humidity and temperature were independently installed for check. The monitoring was each time carried out for 24 hours. Next there were collected a samples for laboratory analysis for product quality. During storage both the temperature and relative humidity of the control variant increased substantially, with temperature values reaching up to 41°C and relative humidity values 100%. The progress of temperatures was almost identical with all the measurements, that is why we present only the average values. The relative humidity of active ventilated variant increased up to 100% but temperature only up to 15°C. The values of humidity of passive ventilated variant were the same (100%) but values of temperature were lower instead of control variant. The highest measured temperature was about 22°C. The conclusion we may draw here says that the best way is passive air circulation. The lowest temperature was measured at variant with fan and it is most important for storage quality of hops but this variant is more expensive due to electric power.

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39-46 D. Hoffmann, P. Heřmánek, A. Rybka and I. Honzík
Design a drive for interaxle mechanical cutter used in low trellises
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Design a drive for interaxle mechanical cutter used in low trellises

D. Hoffmann*, P. Heřmánek, A. Rybka and I. Honzík

Czech University of Life Sciences Prague, Faculty of Engineering, Departmentof Agricultural Machines; *Correspondence: dhoffmann@tf.czu.cz

Abstract:

A mechanical cutter (similar to a special sprinkler for chemical pruning) serves toprune new hopvine shoots in spring. Depending on the right timing and quality of pruningdepends the later yield, which is why pruning is one of the most important agrotechnicaloperations. Double-disc mechanical cutter used with high trellises cannot be used with thetechnology of low trellises. Due to the effort to minimise the chemical environmental burden,special sprinklers for chemical pruning used abroad are considered inappropriate. This was thereason which led to a design for a mechanical cutter operating in low trellises. The articledescribes a hydraulic circuit design and laboratory measurements of an experimental model ofmechanical cutter.

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117-124 L. Vent and A. Rybka
Influence of humidity on the quality of baled hops at grower
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Influence of humidity on the quality of baled hops at grower

L. Vent* and A. Rybka

Czech University of Life Sciences Prague, Faculty of Engineering,Kamýcká 129, Praha 6 – Suchdol, Postcode 16521, Czech Republic;
*Correspondence: lvent@tf.czu.cz

Abstract:

Nowadays, in most of cases cured hops are pressed into square bales instead of roundbales. The specific weight of packaged hop is about 22% higher in the square bale and intensityof moistening of packaged hop is very important in this case. There is an increased risk ofdampening of hops in the square bale when the moistening intensity is too high. In the oppositecase is increased risk of destruction of hop cones due to low moistening intensity. The aim ofthis work was find out the influence of the intensity of moistening of hops before pressing intothe square bales on the development of humidity and quality of hops after pressing duringstorage at the grower. There were pressed square bales with humidity of hops from 9.2% to16.2%. The square bales with hop’s humidity 9–10% represented a dry variant, square baleswith hop’s humidity 11–12% represented an normal variant and square bales with hop’shumidity 13% and higher represented a wet variant. The square bales were stored on the firstfloor of the drying machine house at the grower. The range of storage temperature was from 7to 40 °C. All square bales were of the same condition. Humidity of the hops was monitoredduring 10 days. At the end of the measurement, there was carried out a laboratory analysis ofhops of all square bales. Samples were analysed for content of α – bitter acid and destruction ofhop cones. During storage, the humidity of wet variant dropped from 14.2 to 12.7% and thehumidity of dry variant increased from 9.37 to 11.1%. The destruction of hop cones was highestat dry variant (28%). On the contrary the lowest value was at normal variant (12.3%) and it isabout 43% less. However, the dependence of destruction of hop cones by humidity at asignificant level α = 0.05 has not been proven. There was no proven differences of content ofα – bitter acid between all three variants. The highest value 4.9% was at wet variant. We foundout a direct dependence of content of α – bitter acid on the humidity of hops in this case. Theresults of content of α – bitter and destruction of hop cones show that the best one was normalvariant with starting humidity from 11.2 to 11.6%.

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125-130 L. Vent and A. Rybka
Physical characteristics of picked hops during storage
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Physical characteristics of picked hops during storage

L. Vent* and A. Rybka

Czech University of Life Sciences Prague, Faculty of Engineering,Kamýcká 129, Praha 6 – Suchdol, Postcode 16521, Czech Republic;
*Correspondence: lvent@tf.czu.cz

Abstract:

To prevent interrupting the process of drying or picking due to lack or surplus ofhops coming out of the picking line, hops, in most cases are placed in a storage container.. In acontainer, however, hops are layered, thus temperature and humidity increase owing to anincreased intensity of hop cones breathing and an insufficient airing, i.e. they mowburn. In theprocess of breathing a cone loses important substances which results in its deteriorated qualityand correspondingly in the poor quality of the final product. Our task was to observe the courseof hop temperature and humidity in a storage container and to compare it with the checkvariant, which was loosely spread hops outside the container. Data of temperature and humiditywere continually recorded by COMET D 3631 measuring equipment with N1ATG8/Cmeasuring probe by the Comet System company. Other analogue sensors to measure humidityand temperature were independently installed for checking. The monitoring was each timecarried out for 24 hours. During storage both the temperature and humidity of the hops in thecontainer increased substantially, with temperature values reaching up to 49 °C and humidityvalues 100%. The progress of temperatures was almost identical with all the measurements, thatis why we present only the average values. The highest temperature inside the container was inthe range of 39 °C to 49 °C with individual measurements. The temperatures of the checksamples were identical with the air temperature in the daytime with all the repeats. Themaximum temperature of the check samples ranged from 21 °C to 27 °C with eachmeasurement. In the same way as with the temperature, during the individual measurements thehumidity showed similar progress and the measurements did not differ from each other in anysubstantial way. The humidity level in the container rose up to the maximum value of 100%already two hours after the measurement had started and stayed like this until the end. Thehumidity of the hop check samples was 2.24% higher than the air humidity, which might beexplained by water vapour emission due to an increased intensity of hop cones breathing. Theconclusion we may draw here says that with an increasing volume and, probably above all,height of the stored hops layer, the influence of the surroundings on the conditions inside thecontainer will decline.

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