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Milking machine is the machine, which is used to milk cattle. It revolutionized the dairy farm industry, as it is an efficient and time saving means of milking machine. The development of the milking machine has been by trial and error from a very early time. Its development is still continuing. This paper deals with the explanation of the parts involved in the milking machine.
This also involves the working of the milking machine and the certain advancement involved in it.
Milking machine as the name just is the machine, which is used to milk cows. It plays an important role on the dairy farm as an efficient means of milking cows. This machine is one of the few devices which has direct contact with living animal tissue. A milking operation that results in discomfort to the cow and is caused by faulty milking equipment or techniques may lead to injury or mastitis.
Consequently, a person should thoroughly understand the basic operation of the milking equipment and fully realize the significance of maintaining the equipment in good condition at all times and of employing good milking techniques. This fact sheet describes the basic operations involved to help give a better understanding of milking machines.
Milking machine operates on the principle of partial vacuum. vacuum is created in a closed space when the air from the closed space is removed. Partial vacuum when air is partially removed
The frequent question that comes to everyoneâ„¢s mind is that is it only for cows no it is not ,it can be used for others cattle also such as sheep, goat etc. but with appropriate changes made to the machine.
The milking machine performs two basic functions:
1. It causes milk to flow from a teat by exposing the teat end to a partial vacuum.
2. It massages the teat in an effort to relieve the effects of a continuous milking vacuum
EARLY COW MILKING MACHINES
Development of a usable milking machine took several decades of trial and error, unlike the rapid development and acceptance of other dairy innovations. There was a lot of discouragement towards milking machine, stating that it was unnatural or intrinsically injurious to the cow.
The great variety and number of early milking machines can be categorized into two groups, the first group are those that tried to emulate hand milking and they were called mechanical pressure devices. The second group are those that tried to emulate the sucking calf and they were called vacuum devices.
The earliest devices for mechanical milking were tubes inserted in the teats to force open the sphincter muscle, thus allowing the milk to flow. Wooden tubes were used for this purpose, as well as feather quills. Skillfully made tubes of pure silver, gutta percha, ivory, and bone were marketed in the mid-19th century.
The earliest vacuum milkers used a large gutta percha cup, fitting over the entire udder, and connected to a hand pump. Hodges and Brockenden secured an English patent for such a device in 1851. A hand cranked suction pump drew milk from all four teats at once. Such devices created a continuous suction on the udder, damaging the mammary tissue and frequently causing the cow to kick.
EARLY VACUUM MACHINE
The first successful use of teat cups with a vacuum milker is found in the 1860 patent of L.O. Colvin. However, the Colvin milker still subjected the cow's teats to constant vacuum, causing blood to pool there. William Murchland invented a very successful vacuum milker in 1889, which hung suspended under the cow. He was granted a U.S. patent in 1892.
The pulsator was first introduced in the "Thistle" milker, using a steam driven vacuum pump. While the Thistle machine presented problems of sanitation, it proved an efficient milker. The pulsator, resulting in this intermittent flow is what finally led to a really workable milking machine.
There were a great variety of mechanical devices to simulate hand milking. Most of these devices incorporated rollers or fingers that intermittently pressed on the teat, often working from top to bottom. Some of these devices were simple; others composed of hundreds of parts and worked by cranks.
Mechanical milkers could not compensate for the changing size of the cow's teats as milking progressed, and did not milk to completion. These disadvantages inturn led to the development of vacuum devices.
The main parts of milking machine parts are
Â¢ Teat cup shells and liners
Â¢ Milk receptacle
Â¢ Vacuum pump and gauge
Â¢ Vacuum tank
The other parts help in the proper working of the milker units. The vacuum pump removes air from the vacuum tank. The vacuum tank consists of milking line and pulsating line. Regulator is placed in the milking line. The teat claw is connected to milking line through the long milk hose. The milk from teatclaw reaches the receptacle through the milking line. The pulsator along with vacuum gauge is connected the pulsating line.
1. Pulsator: -
The pulsator is the heart of the milking machine and it works like the heart, it has a valve and it oscillates alternatively allowing air and vacuum into the system.
The function of the pulsator is to allow intermittent massage of the teat end to prevent swelling. The working of pulsator brings about the working of the milker unit. As the pulsator operates, it causes the chamber between the shell and the liner to alternate regularly from vacuum to air source.
There are two classifications of pulsator and they are based on: -
Based on pulsations
Milking machines are designed to operate with all four teat cups simultaneously milking and then all four teat cups massaging.
Pulsators are of an "alternating" type. Operate with an alternating action; that is, while two teat-cup liners are milking the other two liners are massaging. Depending on the manufacturer, the alternating action may be from the left side to the right side or it can be from front quarters to back on an individual cow. This results in alternately milking the front and then rear quarters. This helps to even out the milk flow and reduce flooding of the claw
Based on activation
Pulsators can be vacuum operated. The vacuum-operated pulsator uses air to move the plunger or slide valve, which covers or uncovers the air passages to produce the pulsating action. The plunger or slide valve may be housed in oil for smoother action. The rate of pulsation is controlled by a needle valve, which may be factory set or may be manually adjustable. Temperature changes tend to affect the pulsation rate of vacuum-operated pulsators; so be conscious of this factor and maintain the pulsator at normal operating temperatures to help reduce rate variations.
Pulsator can be electrically operated. The electric pulsator may be operated by a master control which sends, via an electric current, the proper
command to the pulsator to perform a preset pulsation rate and ratio. The electric pulsator is unaffected by temperature and therefore, has the advantage of producing a constant pulsation rate
Some Terms Related to the Pulsator
A cycle refers to the total time in seconds that a pulsator takes to complete one milk phase and one massage phase.
The pulsation rate refers to the number of cycles that the pulsator makes in one minute. Pulsators on the market have pulsation rates ranging from 40 to 60 cycles per minute.
The pulsation ratio is the length of time in each cycle that the pulsator is in its milk phase compared to its massage phase. The pulsation ratio may be expressed as a simple ratio or it can be expressed as a percentage. Examples of pulsation ratios are as follows: 60:40 pulsator means that within any given cycle the teat-cup liner will be open and milking 60% of the time and closed or massaging the teat 40% of the time.
2. Teat Cup Shells & Liners
The teat cup shells and liners are the milking unit. The shell liner is made of synthetic rubber or silicon and the teat cup shells are made of stainless steel. The liner inside the teat cups of the milking unit is the only part of the machine that comes in contact with the udder of the cow.
Thus the weight of the unit is usually adjusted to the vacuum level to provide the desired tension on the teat to allow proper positioning and adequate milking action.
The teat cup shells and the shell liner form a vacuum chamber between them, which allow milk to be removed from the teat and also provides massage of the teat end. The size inflation used should correspond to the shell size.
The surface of the shell liner becomes pitted with use and cleaning which aid in the spread of infectious bacteria which cause mastitis. So they must be changed on schedule. They also lose their elasticity, with use, and will not provide proper teat massage.
3. Teat-Cup Claw
The milking claw connects and supports the four shells and inflations and serves as a collection site for the milk from the four quarters. The "tail piece" of the inflation carries the milk from the teat end into the claw .The claw is connected to the milk receptacle by the long milk hose and milk flows from the claw to the milk receptacle through this long milk hose. The claw should be of adequate size to avoid flooding. Most claws admit air through a small hole in the claw to aid milk flow.
The function of the regulator is to admit air into the system to keep the vacuum at the recommended level. It is placed in the milking line. Normally, the vacuum pump creates a level of vacuum greater than needed in the milking unit.
The regulator senses the changes in vacuum (due to leaks, attaching and removing the milking units, slippage, etc.) and controls the amount of air admitted into the vacuum system or it closes down to exclude excess air in order to maintain the desired vacuum level within a very narrow range. The controller may be a weighted diaphragm or spring-operated device.
5. Vacuum Pump
Milking machines depend upon a partial vacuum for their operation. The function of the vacuum pump is to remove air from a closed system, thereby creating a partial vacuum thus reducing the pressure of the air.
Atmospheric pressure will cause mercury to rise in a column to 29.9 inches high at sea level. Most milking systems will create a partial vacuum of 10.5-12.5 inches of mercury.
6. Vacuum Gauge
The vacuum pressure is measured by a vacuum gauge. It is still measured in inches of mercury (Hg) or in kilopascals (kPa) to indicate the vacuum pressure present. One inch of mercury is equal to 3.38 kPa. A vacuum gauge should be located on the vacuum line.
The milking process consists milk phase and massage phase. As the pulsator operates, it causes alternative closing and opening between the shell and the liner to alternate regularly from vacuum to air source. Keep in mind that the inside of the teat-cup liner is under a milking vacuum at all times.
In this phase air is admitted between the shell and liner, the liner collapses around the cow's teat. The pressure of the collapse liner is applied to the teat giving a massaging action. This is called the rest or massage phase. Milk does NOT flow from the teat during this phase.
In the milk phase, the space between the liner and the shell is exposed to the vacuum by way of the pulsator. The fact that there is now equal pressure on both sides of the liner causes it to open. The end of the cow's teat exposed to the vacuum and the influence of internal milk pressure within the cow's udder causes the milk to be drawn out through the teat opening because the pressure is lower outside the teat end.
It is essential that inflations be installed properly and in the correct shell. Twisting will prevent normal function. Some inflations are square, others have ribbed sides or special tops. Some admit air into the tailpiece of the liner and are called a vented inflation. This is done to avoid flooding with milk. It is very important that inflations are changed on schedule; otherwise they become worn, allow buildup of milk deposits and bacteria and assist in the spread of contagious forms of mastitis. Tubes where the liners are attached to the claw are not bent or damaged, as this will block milk flow, slow milking and cause teat irritation. Be sure the long milk hose is in good condition, does not leak, is not too long. Avoid loops in this line that may cause a "backup" of milk & flood the claw.
The basic cleaning steps recommended for use in all systems are:
Â¢ Plenty of cold-water rinse to flush milk from the machines
Â¢ Hot detergent wash
Â¢ Hot water rinse to remove detergent residues
Â¢ Optional sanitizing rinse with chemical sanitizer or hot water before milking
Three systems can be used to clean milking machines
Â¢ Reverse flow
The jetter or third-line cleaning system has become the most popular and efficient cleaning system for milking machines. This method relies on vacuum to draw the cleaning solutions from holding vessels located in the end of the pit or milkroom through a separate third line set up with jetters for attachment to each milking cluster.
Several types of jetters are available. They range from individual rubber cups into which the teat cups are inserted to those that are fixed so that the cups can be quickly fitted over protruding fingers.
Â¢ Time spent on putting cups on jetters
Â¢ Some types of jetter can cause distortion in the mouthpiece of liners
Â¢ Some lines are not compatible with all types of jetters
Â¢ Temptation to circulate for too long or too often
After milking, the vacuum pump is switched off and the dropper taps or clamps are opened and cleaning solutions are pumped into the receiver and then to waste through the cups. Regardless of the size of the milking machine, cleaning can be completed in five to ten minutes by reverse flow. However, the operating cost of reverse-flow cleaning is from two to three times that of jetter or bucket cleaning systems because more water and special liquid detergents are used.
Â¢ Safer as it eliminates carrying water and dangerous chemicals
Â¢ Reasonable cost to install and operate
Â¢ Low maintenance costs
Â¢ Allows flexibility in cleaning programs
Â¢ Ease of operation encourages a full cleaning procedure
The bucket system
This is time-consuming, hard work, and involves carrying buckets of near-boiling water. However, bucket cleaning still exists in smaller sheds.
Portable milking machine
The specifications of the portable machine
Â¢ Frame is made from hot dipped galvanized mild steel giving a long life
Â¢ 0.5hp oil free, direct drive vacuum pump
Â¢ Runs from 220 - 240v 50hz 13A socket.
Â¢ 140 litres per minute pump capacity
Â¢ 15 litre interceptor tank, made from galvanized mild steel
Â¢ Easily adjustable vacuum regulator
Â¢ Reliable, easy to service pulsator
Â¢ 30 litre plastic milking bucket
Â¢ High capacity claw piece
Â¢ Stainless steel teat cup shells
Â¢ Medium bore liners
Solar powered milking machine
With power cuts hampering dairy farms, a new machine has been introduced in the market which uses solar power to milk animals.
The machine creates no sound or air pollution, The machine comprises a pulsator and vacuum pump apart from the solar panels and battery to store power.
The solar milking machine ensures hygienic milking practice matching international standards. The machine needs about 2 sq. m to install near the cowshed so that the solar panels are exposed to sunlight for about six hours. It provides power for milking 25 animals twice a day. The machine can be utilized as a solar power station in case it is not to be used for milking.
A direct current motor will have to be connected to the device for converting power for use in the household electric circuit. The machine will be of much use to dairies as well as rural households.
Milking machine is very popular in developed countries like Australia, United Kingdom, and New Zealand. But now it is gaining importance in developing countries such as India, Pakistan etc. But the implementation in developing countries is by making minor modifications to the machine. The development in milking machine has been incredible and is still increasing to make milking of cattle more efficient, hygienic, economical and time saving.
Influence of Vacuum Level and Overmilking on Udder Health and Teat Thickness Changes in Dairy Ewes, C. Peris, J. R. Diaz, S. Balasch, M. C. Beltran, M. P. Molina, and N. Fernandez., December 1, 2003
I. INTRODUCTION 1
II. EARLY COW MILKING MACHINE 2
III. MILKING MACHINE 4
IV. PARTS 5
a. Pulsator 5
b. Teat cup shells and liner 8
c. Teat claw 9
d. Regulator 10
e. Vacuum pump 10
f. Vacuum gauge 11
VI. WORKING 12
VII. MAINTENANCE 14
VIII. CLEANING SYSTEM 15
IX. ADVANCEMENT 17
X. CONCLUSION 19
XI. REFERENCES 20