Horticultural Machineries Essay

Horticultural mouldry be the unlike tractors, orbitual cultivators, drills, atomisers, root veggie reapers and other equipment of interest to horticulturist POWER UNITS USED FOR HORTICULTURAL PURPOSES The pick up for special types of power building block and or civilization implements arises when it is necessary to trim between fruits trees or halyard, where the clothe distance has already been decided and the equipment has to aline to it. narrow rows of fruits and haps around quantifys necessitate the enjoyment of extremely narrow tractors, with over on the whole widths of about 4 ft (1. m) such tractors require speci altogethery adapt mounted equipment and use among other implements, types of plough which ar designed for plugging up or absent from both sides of rows of haps or fruits some of special cultivation implements employ implicate. 1. SMALL ROTARY CULTIVATORS A forget me drug cultivator is a tool that is utilise to loosen, aerate and prep atomic nu mber 18 colly for new target or to enhance the condition of stomachground for existing plantings. A carousel cultivator a great deal known as rotatiller or roto cultivator consists of neat rotating tins or blades that argon typically do of steel or aluminum.The rotating tins drudge into the smirch, loosening and aerating the begrime in a process known as cultivation. Cultivating filth is in-chief(postnominal) because over a period of time territory tends to compact and demandingen. This apprize make it to a greater extent(prenominal) than difficult for plant to pick up the proper level of urine supply and nutrients. Breaking up and loosening compacted basis makes it easier for irrigate and nutrients to f mild by dint of and by the shit and into plantings. A littleened set cultivator is hand held cultivator either self propelled or powered. It looks a lot like a lawn mower.A self propelled rotary cultivator has tins (blades) given up to a pole that is similar to a huge stick and the midpoint abuser simply pushes it to cultivate a lawn or garden. M both self propelled cultivators assume aluminum tines which some users nurture found to be too argus-eyed weight unit for allthing more than light set outr use. There atomic number 18 therefore self-propelling cultivators that utilize a heavier weight metal for the rotating tines, which numerous find to be more powerful. However, the heavier weight of these tools whitethorn make it more difficult to use for an extended period of time.A motorized cultivator is powered by a teeny swasholine or electric car motor it is often employ on amply grown gardens. The tines of a rotary cultivator roll in the opposite direction of the wheel and till to a perspicacity of 8 to 10 inches traffic patternula width of the small rotary cultivator sphere from 4 8 ft (2 2. 4m) with power rating ranging from 1 hp to 8 hp (0. 75kw) 2. WALKING brochureOR The move tractor or two-wheel tractor is a tractor with one and only(a) axle self powered and self-propelled which depose cleave and power various f beef up implements such as a tractor, cultivator, or harrow, a plough or various seeders and harvesters.The operator usually walks stool it or sides the implement universe towed like a four-wheel tractor, the walking tractor is designed to run some attachments with a single power reference work and gives thousands of hours of services. These tractors are fitted with engines of up to 3hp (2. 2 kw). Some walking tractors now constructed have a power rating of up to 12 hp. 3. NARROW TRACT TRACTOR Narrow track tractors are of interest to horticulturalist who frequently need to move a heavy spraying machine as well as to carry out plugging and other tillage operations.Such tractors with engines of 25 45 hp (19 33 kw) may have overall dimensions as small as about 1m wide as 1. 3m high. They are fitted with 4 tyres and joint frame steering of a type that can pr ovide a very small put outing circle, they have lowly weight to stomach work beneath trees. Hydrostatic transmission assists in achieving a legal order of delivering power to the drive wheels. 4. COMPACT L-WHEEL TRACTOR A compact utility tractor (CUT) is a smaller version of an agricultural tractor designed primarily for landscape gardening and use in field with narrow spaced tracks.Typical CUTs range from 20 50hp (15 -37 kw) with obtainable PTO horse power ranging from 15 45 (11 -34 kw) CUTs are often equipped with both a mid-mounted and received idler PTO, especially those downstairs 40 hp (30 kw). modern CUTs use hydrostatic transmissions but more variants of gear-drive transmissions are also offered from low priced, simple gear-transmission to call atomic pile glide-shift transmissions. CUTs require special smaller implements than full sized agricultural tractors. truly common implements include, the box blade the hitr blade, the landscape rake, the post hole d igger, the rotary cutter, a broadcast seeder, and a rotary tiller.SOIL CULTIVATION IMPLEMENTS 1. treat The plough is a tool used in farming for initial cultivation of blot in preparation for sowing seed or planting. It has been a basic instrument for approximately of recorded history and represents one of the study advances in agriculture. The primary purpose of plugging is to turn over the fastness socio-economic class of the soil, bringing impertinently nutrients to the protrude art object burying rats and weed seeds, allowing them to break overmatch. It also aerates the soil, allows it to hold moisture demote and provides a seed-free medium for planting on alternate crop. The plough is made up of the sideline components . The coulter The function of the coulter is to cut the soil. It is this component of the plough that clears the path. The coulter is a blade or sharp-edged disc attached to a plough so that it cuts through with(predicate) the soil vertically. 2. The Mold Board It is the part of the plough which pushes apart the soil, turned over by the coulter. It is either rounded, helical, helically cylindrical or a curved rod. 3. move or so-Beam The part that connects the rest of the plough with the animal or tractor. Its fix and length influences the depth of the coulter and to a lesser extent ts width. 4. Plough Share The plough-share is the central part of the plough on which the other major(ip) parts are intractable (plough-beam, mold boards coulter, contre-sep). 5. Contre-sep Allows the stabilization of the plough while supporting the hilt. Any standard steel can be used for its construction. 6. The Hilt Permits the longitudiral stabilization of the plough pliding on the bottom of the trench longitudinal constancy is check offd by reaction between the ground supports on the soil, the support points on the front and the wind of plough and by the wheel. SOIL sterilisation discolouration sterilisation is a chemic or physical pro cess that consequents in the death of soil organisms. This practice provides secure and quick relief of soil from substances and organisms harmful to plants such as bacteria, viruses, fungi, nematodes and other pests. Many of the organisms in the soil helps breakdown larger pieces of organic matter into small particles which are more easily absorbable by plants but they could be in the soil poisonous fungi, bacteria and insects and weed seeds. Soil sterilization helps to do away with these detrimental organisms and seed widows weeds.There are two major modes of soil sterilization chemic mode and physical system. 1. Chemical methods includes the use of herbicides and fumigants 2. personal methods include the use of traveler and solar energy a. STEAM STERILIZATION Soil piping is a farming technique that sterilizes soil with go in open fields or green houses. Detrimental organisms and weeds are killed through induced gamy locomote which causes their cell anatomical stru cture to physically degenerate. Biologically, the method is considered a partial disinfection. Important oestrus-resistant, spare-farming bacteria start and revitalize the soil after cooling down. steam leads to a strengthen resistance against plant disease and pests. METHOD OF STEAMING 1. Surface turned on(p) it is the application of catch fire directly on the surface of the soil employ various methods which include area sail steaming, the steaming hood, the steaming harrow, the steaming plough and vacuum steaming with drainage subways or unstable pipe system. i. Sheet steaming Surface steaming with special sheets is a method which has been open for decades in other to steam large areas reaching from 15 to 400m2 in one amount.The usage of heat resistant, non-decomposing insulation fleece saves up to 50% energy signs the steaming time significantly and improves penetration. The currenting time depends on soil structure as well as external temperature and amounts to 1 1. 5 hour per 10 cm steaming depth. ii. Steaming with Vacuum This is induced through a alert or frozen installed pipe system in the depth of the area to be steamed. It is the method that reaches the best penetration. Despite high capital cost, the rooted(p) installation of drainage system is reasonable for intensively used areas since steaming depth of up to 80 cm can be achieved.The steaming area is cover with a special steaming sheet and weighted all around as with sheet steaming. The steam is injected underneath the sheet through an injector and shelter tunnel while with short areas up to 30m length steam is frontally injected, with longer areas steam is induced in the middle of the beet using a T-connection branching out to both sides. As soon as the sheet is inflated to approximately 1m by the steam pressure, the suction turbine is switched on. First, the manner in the soil is removed via the suction hoses. A vacuum is make and the steam is pulled downward.When the requ ired steaming depth has been reached, the ventilator runs non-s authorize and surplus steam is blown out. To ensure that, this surplus steam is non lost, it is fed back end under the sheet. iii. Steaming with hoods A steaming hood is a mobile pull consisting of corrosion resistant materials such as aluminum, which is put down on to the area to be steamed. In contrast to sheet steaming, cost-intensive working(a) steps such as lying out and weighting the sheet dont occur, however the area steamed per working step is smaller in accordance to the size of the hood. . SOLARIZATION Solarization of soil is a much more non-chemical environmentally friendly way of soil sterilization and this involves using the power of the sun to get rid of many disease and pests that causes damage to varied types of grasses. It is a relatively easy method of sterilization and involves covering up the soil that bequeath be established with a clear p sufferic material to capture the radiant heat and ener gy from the sun to kill the pathogens in the soil.Not only does this method get rid of about of the unwanted diseases and pests but it also stimulates the relense of nutrients from organic matter present in the soil. c. ELECTRIC SOIL STERILIZER The electric soil sterilizer is often used for sterilization of small touchstone of soil needed for the nursery or in green houses. The equipment is fill to the top of the container and then the unit is plugged in. the ther intimatelyat is then set to the correct sterilizing temperature (about 80c). The indicator light will glow until the quite a little is done.After the light goes off, wait 15 minutes, then pick up the unit and the sterilized soil will drop out the bottom. It eliminates weeds and disease, kills weeds practically 100% kills soil-borne insects and in general, all of the bacteria, fungi and virus organisms that are harmful to commercial crops. d. CHEMICAL SOIL STERILIZATION Chemical sterilization of soil refers to the use of various chemical to sterilize soil. The chemicals to be used must give off gas which is sufficiently poisonous to ensure the destruction of pest, diseases and weeds, yet without harming the beneficial, organisms in the soil.The efficiency of chemical sterilization varies greatly, not because of precise chemicals involved, but because of the condition of the soil, its moisture content and most importantly, the prevailing temperature. This should also ensure even distribution in the soil to be sterilized some chemicals used for soil sterilization include 1. Methyl bromide gas Methyl bromide is a fumigant that is most often used in vegetable and farm production. It is usually apply s gas injected into the soil and then covered by a thin plastic shield in order to slow the travail of methyl bromide from the soil to the atmosphere in that detail area.It is a dangerous chemical and when humans are exposed to high concentrations of this chemical it can result in respiratory system fai lure, central restless system failure and damage to the skin, eyes and lungs. Because of the dangers associated with the application of this gas and the detrimental effects that it has on the ozone, methyl bromide is beginning to become less and less used. 2. Vapam Vapam is an effective liquid fumigant for the image of nematodes, insects, weeds and soil borne diseases.It is not very volatile which style that it is not easily evaporated At normal temperatures and before applying this chemical it is always wise to cultivate the area that is cosmos treated in order to deliver the vapam in a furnish manner Before application the soil moisture of the field be between 50% to 80% field capacity this chemical can be applied in a number of ways some bring through sprinkler sprinkler and flood applications provide the best coverage and then the most successful this product is however toxic to fish so you should not apply this to areas where the surface urine supply can easily be wash ed on to lakes or streams, 3.Basamid Basamid is a granular and eliminates weeds, nematodes grasses and soil diseases. When this chemical ingredient hits the moist soil the graduals breakdown and release gases that spread in the soil and these gases eliminate the unwanted disease or pests. When applying basamid it is very important to keep the soil wet for 2 week, prior to the application in order to meet the right soil moisture level and all(prenominal) comprised on to the soil to about 15cm using a rotary cultivator or something that has this same effect .After doing this, it is important to pestle the area with a plastic of some sort of properly treat the soil, keeping all the volatile and highly toxic gases in that specific area. SOIL STERILIZING EQUIPMENT (LOKO BOILER) A kettledrums or steam generator is a turn used to create steam by applying heat energy to water. The form and size depends on the application the railway locomotive Boiler is portable mobile steam engine w ith same features as the large one.The only divagation is variation in size of component part the LOKO Boiler is made up of the following part 1. FIRE TUBE BOILER This is a single furnace, three material body type in flame provide kettledrum. Heat-flue gases-travel is through three different sets of subway systems. All the bathes are surrounded by water which absorbs the heat . As the water turns to steam, pressure builds up with in the boiler one enough pressure has built up the engineer will open the main steam outlet valve slowly. Fire tube boilers are also known as pasture tube and donkey boiler. . peeing TUBE BOILERS The large tube like structure at the top of the boiler is called the steam drum. You could call it the heart of the boiler. That is where the steam collects before being felld from the boiler. The hundreds of tube start and eventually end up at the steam drum. Water enters the boiler, pre-heated at the top. The stifling water naturally circulates through the tubes down to the spurn area where it is hot the water heats up and fertilises back to the steam drum where the steam collects.Not all the water gets turn to steam, so the process starts again. Water keep on circulating until all of it turns in to or becomes steam. BOILER MAIN COMPONENTS BOILER SHELL- The out cylindrical portion of a pressure vessel. BURNER A device for the introduction of fire air in to the furnace at the decreed velocities, turbulence and concentration. The burners is the principal device for the vent of oil and or gas Burners are normally functiond in the vertical walls of the furnace.Burners along with the furnace in which they are installed, are designed to born the force out properly. SMOKE TUBE The second/third phase are formed by thick walled sens tubes which are welded in to the end plates the arrangement of the smoke tubes considers the recommendation of ascending flue toures in order to prevent the information of residual-or lingering gases the first phase is a combination of a furnace tube and burning at the stake sleeping accommodation suspended by stay bar and completely surrounded by water cock-a-hoop valuable radiant heat assignence from all surfaces.The second pass is a nest of straight 50mm boiler tubes expanded in to the upper zone of the combustion chamber and running in parallel to the furnace tube terminating at the front plate of the reversing chamber. The third pass is a nurture nest of 50mm boiler tubes running from the upper zone of the reversing chamber to the rear smoke box for exhausting to atmosphere. FRONT REVERSING CHAMBERS The front reversing chamber is equipped with large doors allowing free access to the smoke tubes and easy victuals and cleaning High-quality tightening material guarantees the gastight closing of he doors. DRAIN rap A valve connection at the lowest point for the removal of all unwanted elements from the pressure parts. FEED PUMP A pump that supplies water to a boiler. FEED WATER water introduced into a boiler during operation. It includes lay out and return condensate. FURNACE An enclosed space provided for the combustions of enkindle. INSULATION A material of low thermal conductivity used to reduce heat losses. SAFETY VALVE A spring loaded valve that automatically opens when pressure attains the value setting used to prevent excessive pressure from building up in a boiler.SAFETY SHUT- OFF VALVE A manually opened, electrically latched, electrically operated precaution shut-off valve designed to automatically shut-off fuel when de-energized. WATER LEVEL The elevation of the surface of the water in a boiler. ACCUMULATOR A pressure vessel containing water and/or steam which is used to store the heat of steam for use at a lale period at some lower pressure. FIRE BOX The fire box is surrounded by water in the outer fire box shell and so enchanting radiant heat from the fire.The gap between the inner and outer fire boxes is maintained by hu ndreds of rigid stays. AIR ATOMIZING OIL BURNER A burner for firing oil in which the oil is atomized by compressed air, which is forced into and through one or more streams of oil which result in the breach of the oil into a fine spray. BAFFLE-TYPE COLLECTOR A device in gas paths utilizing baffle so arranged as to deflect body particles out of the gas stream. BAG filtrate A device containing one or more cloth bags revering particles from the dust lateen gas or air which is blown through it .BAG-TYPE COLLECTOR A filter in which the cloth filtering medium is made in the form of cylindrical bags. BREECHING A duct that transports the products of combustion between parts of a steam generating unit or to the lot. CIRCULATOR A pipe or tube to pass stream or water between upper boiler drums usually lactated where the heat absorption is low. Also used to apply to tubes connecting heater of horizontal water tube boilers with drums. STEAM GENERATING UNIT A unit to which water fuel and air supplied and in which steam is generated. t consists of a boiler furnace and fuel burning equipment, and may include as component parts water walls, top-notch heater, reheater, economizer, air heater, or any combination thereof. STEAM cartridge extractor A device for removing the entrained water from steam. STRAINER A device, such as a filter, to retain solid particles allowing a liquid to pass. SMOKE BOX The smoke box is an extension of the front end of the boiler barrel. Exhaust steam from the cylinder passes through the blast pipe into the chimney and creates partial vacuum. This causes hot gases to be drown through the grate and fine hole door.The smoke box also contains the main steam pipe to the steam chest, blower, tops(predicate) heater header, tube and exhaust for the vacuum ejector where fitted. BRICK ARCH The brick patronising serves several purpose. It protects the fire box tube plate from the direct flame of the fire, radiates heat to prevent rapid fluctuation of th e tube plate temperature and ensure thorough combustion of volatiles by lengthening their path from the fire to the tube plate. FIRE DOOR Fire hole door vary from locomotive to locomotive. They gives access to firing and can be adjusted to control the flow of secondary air.BAFFLE PLATE The baffle plate place in the fire hole is designed to direct the secondary air down towards the fired bed in order to mix thoroughly with the hot gases and flames. FUSIBLE PLUGS Fusible plugs are screwed into the fire box crown. They are of nerve and have a lead cure. If the water level in the boiler drop and uncovers the fire box crown, the lead melt allowing steam to consort into the fire box. This warns the engine men and help to deaden the fire. Both injectors should be put off immediately if this occurs and steps taken to remove or deaden the fire.SUPERHEATER The extremely heater consists of superior heater header and super heater elements. Steam from the main steam pipe arrives at the hard steam chamber of the super heater header and is fed into the super heater element. Super heated steam arrives back at the super heater chamber of the super heater header and is fed into the steam pipe to the cylinder. Super heated steam is more expensive. ENERGY parsimony DEVICES OF THE BOILER Economizers commute a portion of the heat in the stack gases to water being fed to the boiler. It is a heat exchanger installed in the exhaust stack that pre-heats the boiler feed water.AIR PRE HEATER Transfer heat from hot stack gas to air that is to be confused with fuel for combustion this device saves energy by increasing the temperature of the mix of fuel and air prior to combustion, so more of the heat of combustion is available to heat water. TURBULATORS Twisted pieces of metal inserted in the tubes of fire tub boilers, causes hot gases to travel more slowly and with more turbulence, resulting in better heat modify to the water. OXYGEN TRIM CONTROLS Measure stack gas oxygen concen tration and automatically adjust the inlet air at the burner for optimum efficiency. . 1 ORCHARD EQUIPMENT Orchard equipments refer to the various machines (simple and complex) used on an orchard. Some of the machines include pruners, sprayers, weeders, dusters, and so on The selection of superior of any of these machines is dependent on the nature of work to be carried out at that material time. PRUNERS Also known as pruning shears or secateurs are a type of scissors for cutting off hard branches of trees and shrubs. They are strong enough to prune hard branches of trees and shrubs sometimes up to two centimeters thick.SPRAYERS A sprayer is a piece of equipment that has spray car horn to apply herbicides and fertilizers to agricultural crops. Sprayers range in sizes from man-portable units to trailed types that are connected to a tractor or other self propelled units. There are various types of sprayers which include knap sack, foot, garden, Hand compression, power, stirrup, s elf-propelled crop sprayer, trailed crop sprayer, etc. COMPONENTS OF SPRAYING EQUIPMENT 1. TANK The tank is a unit which holds chemicals, and comes in many different shapes and sizes. 2.PUMP The pump creates pressure that forces the chemical to the schnozs. 3. CONTROL VALVE The control valve controls or maintains pressure and turn off the sprayer. 4. NOZZLE TIP The nozzle tip controls application rate and vex the correct size droplets. 5. FILTER The filter is a unit behind the nozzle tip to reduce entrance or passage of dirty particles and blockage into the system. TYPES OF SPRAYING EQUIPMENTS 1. ULTRA-LOW tidy sum (ULV) SPRAYERS ULV equipment is designed to assert very small droplets, thus ensuring even coverage with low spates.The equipment is based on aerosol, airshear or rotary nozzle techniques. The revolutionary low volume machines use large volumes of air at low pressures to transform liquid into droplets that are dispersed into the atmosphere. Ultra low volume machines are used for applying pesticides, herbicides, fungicides, sterilizers and disinfectants among other chemicals. The ultra low volume machine consists of a blower, a formulation holding tank and a pump. The blower creates a low pressure area and forces air through the nozzles of the machine. breeze pressure can be controlled by adjusting the engine speed up.The nozzles of the machines have a very specific shape, which causes a swiring act of the air stream. The motion is achieved by means of several agitationary fins that forces the air to rotate. The formulation is delivered to the air by means of a supply tube that is situated in the centre of the nozzles. The motion of the airshears the liquid formulation into very small droplets and then disperses it into the atmosphere. Advantages 1. The chemicals dispersed in this type of machine are more concentrated than the chemicals used in other spraying equipments, which increase the killing efficiency. 2.There is lower pretend of inj ury due to low pressure application. The only disadvantage it has is that it requires long application times and higher technical skills. 2. KNAPSACK PRAYERS The knapsack sprayer is a back mounted equipment used by farmers. The tank of a knapsack sprayer is not pressurized and made of grass, or galvanized steel. The pump may be fitted into or outside the tank and sucks the liquid from the tank and expels it through the discharge line. DUSTERS Dusters usually refer to an aircraft used for dusting or spraying large farms with pesticides, though other types of dusters are also employed.Aerial spraying and dusting permits strike coverage of large areas at the moment when application of pesticides is most effective and avoid the need for wheeled vehicles that might damage crops. COMPONENT move OF A DUSTER 1. HOPPER For storing the chemicals in dust form 2. fomenter An agitator is used to keep the dust moving freely deep down the hopper and prevent caking. 3. Metering mechanism- whic h is usually an adjustable orifice that allows the rate of discharge to be varied. 4. Delivery blower which creates an airstream that is used to carry the disintegrate to the target?The major difference between dusters and sprayers is that a sprayer is a machine that applies fluid chemicals to crops in liquid form while a duster is a machine that also applies fluid chemicals but in powdered form. WEEDERS Weeders refers to the various equipments used to ease the task of removing weeds from orchards or gardens. Very common weeders include the fulcrum weeders, the Cape Cod weeders, and the cracle weeder. These weeders come in two styles short handled weeders and long handled weeders.Short handled weeders are preferred for small gardens with small plants while long handled weeders are for big gardens that have bigger weeds. 3. 0. SORTING AND GRADING OF HORT. CROPS compartmentalisation separates into groups different physical properties while leveling separates into groups with diff erent quality characteristics. categorisation and scoring are usually the last separating operations before processing or displaying crops for sale. It should however be remark that damages at the stages of sorting and grading are likely to result in substantial economics loss. REASONS FOR SORTING AND GRADING OF HORT. CROPSSorting and grading of Horticultural crops controls the effectiveness of the subsequent operations because 1. Sorted and anatomyd products are better suited to mechanical operations such as peeling, shading , etc e. g. use of caustic soda or boiling water with vegetables which helps flavor. 2. Sorting and grading is necessary in processes which heat transfer is critical e. g. sterilization. 3. Sorting and grading is advantageous in processes in which uniformity of heat transfer is desirable e. g. dehydration. 4. Sorting and grading of crops gives better control weights filled with standard scale container. . Sorted and graded products fare more attractive in c onsumer use, and allows the sizing of uniformly catering packs like packets of biscuits. equalization and quality judicial separation of Horticultural crops depends on an overall assessment of those properties of the crops which affect its acceptance as a food or as a working substance for the food processor. Grading factors may be grouped under the following size and shape, maturity (e. g. freshness of eggs, ripeness in fruits, aging in meat), food grain (e. g hardness, crispness in corn flakes) and flavor and aroma. GRADING MACHINERYGrading for size and quality is an essential preliminary to marketing of fruits and vegetables grown on commercial holdings, and many types of machines are available to assist this work. Some are cheap and simple sizing or advisement machines for grading cause which has been sorted for quality before hand. Others are complex and expensive machines which incorporate devices to facilitate sorting for quality, exact sizing mechanisms and bins to fac ilitate packing. Grading machinery may be grouped broadly into those which grade by diameter and those which grade by weight. Machines which grade3 by diameter very greatly.Some size in only one or two directions, while others rotate the produce and thereby achieve a more accurate sizing. In general, machines that grade by diameter tend to have higher output, or are rather less expensive for given output then those which grade by Weight. On the other hand, a good weight grader has many advantages. It can be used for any shape, is easily adjustable and can be used for crops that are easily blemished. Grading by weight can also be more accurate than grading by diameter, though good diameter type graders are usually accurate enough for practical purposes.Good graders do little damage to apples, most of the bruising that does occur being caused when the fruit roots into the receiving bin. This is usually miserable compared with damage incurred in picking, and getting fruit to the grade r. Output of graders varies widely harmonize to the number and ability of the operators, as well as according to the machines and aide-de-camp equipment employed. Some graders are equipped with automatic box-tipping devices for loading. The graders in large-scale apple-packing place are often fed by first immersing the boxes in water and then handling the fruit on to the drier by floatation.Outputs on such high-speed machines are frequently limited by the speed of packing. No one grading machine has all the advantages, so choice of a grader requires careful consideration of the most important needs for the conditions in which it is to be used. It is not possible to give an adequate interpretation of any individual(a) machine but below is a brief description of some of the grading machines 1. SIZE GRADERS This operates in two ways as follows a. Produce falls through a circular hole of fixed size.In machines of this type the sizing board has a number of rows of holes of different sizes , and the crop is carried along by means of a series of woody laths operated by a crank mechanism. The effect is to move the produce, without pushing or rolling it, to successively larger holes, until it falls through. b. As produce moves along car transporter, size of opening increases. Graders with mechanisms of this type are common, and include apple graders, in which the fruit is rapidly rolled along by a napped refuge belt, while leaning against a rubber barrier set at a gradually increasing distance from the belt, and machines with diverging rubber belts. . WEIGHT GRADERS In weight graders, each fruit rests in an individual hinged cup, and for much of the journey along the conveyor the cup and fruit are supported in an upright position by a fixed guide rail. At suitable intervals, however, the support is provided by an adjustable lever-type weighing device. When the moment exerted by fruit and cup is sufficient, the cup tips, and deposits the fruit into its allow bi n. 5. 0 MECHANICAL HARVESTING OF HORTICULTURAL FRUITS HARVESTING Is the process of meeting place mature crops or fruits from the fields.Harvesting marks the end of the growing make pass for a particular crop, and the harvest is the focus of a growing season. It is the most labour intensive activity of the growing season. Mechanical harvesting equipment tends to be designed mainly for fruits which are to be processed rather than those for fresh market. The main types of equipment used are combing devices and vibrators, Black currant harvester with shakers, as well as redcurrant harvesters with similar shaker units for grapes. Also available are slider cranks, tree shakers which make use of catching and assemblage devices mostly applicable for olives.IMPORTANCE OF TIME OF HARVESITN OF HORTICULTURAL CROPS 1. It reduces wastage of crop produce since most fruits tend to rot when not harvested in time. 2. It gives the farmer more quality yield. When fruits in particular are harvested b efore they are fully ripe, they tend to be sour. 3. Timely harvesting of leafy vegetables gives room to greater yield as the cut away leaves give room for more to shoot out. COMPONENTS PARTS OF A MECHANICAL FRUIT HARVESTER 1. An impactor for dislodging fruits from a fruit-bearing tree limb mounted on a positioning arm.The arm moves up, down, forward, backward and twists. 2. A collecting conveyor for catching and conveying the dislodged fruits. The conveyor is supported by a frame and is comprised of series of supporters covered by a catching surface having an energy-absorbing flexible material. 3. A transfer conveyor which is supported by a frame and is placed below the outlet of the collecting conveyor. It receives fruits from the collecting conveyor. 4. A collecting Bin which is place below the outlet of the trans conveyor in which harvested fruits are deposited.