Refrigerator Charging Unit

Refrigerator Charging Unit 1. INTRODUCTION Refrigeration: refrigeration is defined as any process of heat removal. More specially, refrigeration is defined as the branch of science that deals with the process of reducing and maintaining the temperature of a space of material below the temperature of the surroundings. Multipurpose charging set is a single arrangement for charging the education and air conditioning unit. This charging set is different than the other method. This is a portable device which can be transferred from One place to another its construction is simple and decorative one. This set is multipurpose device; with charging the unit it can also achieve the vacuum in unit. The weight of gas and pressure of gas going to the unit is directly measured at the time of charging on this set so it is very useful device for charging the refrigeration and air condition unit in laboratories.

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Refrigerator Charging Unit 2. PRINCIPLE OF PROJECT Evacuation : Removing of fully air present in the refrigeration unit is known as evacuation. The main purpose of evacuation process is that for charging the refrigeration unit. The air should not be present in it. If evacuation is not carried out some amount of air is present in the refrigeration unit carried out properly. The leakage problems are rising in it. Definition of Charging: Charging is the process of filling the gas in the refrigeration and air conditioning system. Principle of charging set: This is a new method used for the charging of refrigeration unit differ than the other method. The principle of this charging set is that whenever a charging is carried out by this set how many amount of gas is supply to the refrigeration or air conditioning unit is calculated with the help of spring balance and also determine the pressure of the gas flowing through the charging line with the help of compound pressure gauge.

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Refrigerator Charging Unit 3. PART LIST Sr. no. 1 2 3

Part 3 way valve 2 way valve Charging line Compound

4 5 6

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pressure gauge Spring balance Refrigerant gas

Quantity 2 1 3

Material Bronze Bronze Rubber

1

-

1 1 kg

R-12

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Refrigerator Charging Unit 4. REFRIGERANT The substance, which carries the heat from low temperature region and discharge, the same to the higher temperature region is known as refrigerant. Refrigerant removes the heat in the form of sensible heat as in case of air refrigeration or in the form of latent heat as in the case of vapour refrigeration. The refrigerants, which carry the heat in the form of latent heat and also dissipate in the form of latent heat, are more efficient than the refrigerant, which carry the heat in the form of sensible heat.

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Refrigerator Charging Unit REFREGERANT IN COMMON USE. 1. Ammonia (NH3) : Ammonia is one of the oldest refrigerant uses in refrigeration system. Its excellence thermal property make it an idea refrigerant for ice plant, cold storage etc. Ammonia has the highest refrigerating effect per unit refrigerant capacity. It is much less expensive compare with any other refrigerant. Any moisture, which may enter the system, will be dissolved in ammonia and it attacks many foods, therefore it is not used for domestic refrigerant or where there is danger of exposing foods to leaking ammonia. It attack non-ferrous metal, brass and bronze, but it is non-corrosive to iron and steel. It is widely used in vapour absorption refrigerant system as it soluble in water and easily expelled when heated. 2. Freon –12 or Discholorodifluro methane ( CCL2F2) : It is commercially term as F-12 or R-12. It is used for domestic refrigerator. It is colorless odorless and non-toxic. Therefore it is best suitable for domestic refrigerator. It is used with all types of condenser, air-cooled and watercooled. The boiling point is –29.80c at atmospheric pressure make it suitable for high, medium and low temperature application with any types of compressor. It is soluble in oil; therefore, it is simplifies the problem of lubrication. But its

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Refrigerator Charging Unit disadvantage is that it is costly and leak cannot be detected easily. Its leak detected with the halides torch. 3. Freon -22 Difluromonochloro Methane (CHCIF2) : It has a boiling Point -40"C at atmospheric pressure. It is used for low temperature production. It is also used in packaged air conditioners, where, because of space limitations, Relatively small compressor displacement required with R-22 water-cooled Condensers are used. When air-cooled condenser is used with R-22 is not used. The main advantage of R-22 over R-12 is the smaller compressor displacement required for same capacity. 4. Carbon dioxide (CO2) : It is the oldest refrigerant used. Carbon dioxide is Odorless, nontoxic, non-flammable, non-explosive and non-corrosive Refrigerant. It used in hospitals, theaters, hotels and marine service where safety Is prime consideration? Now days its use is limited for production of dry ice. But the power required for 002 refrigerants is high. 5. Sulphur dioxide (S02): In olden days it was used in domestic Refrigerator. It is now replaced by freon-12. It is colorless and suffocating fluid. In presence of water it forms sulphurous acid, it has low refrigerating effect Compared with other refrigerant and it is heavy irritating and high toxic in nature.

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Refrigerator Charging Unit PROPERTY OF IDEAL REFREGERANT Therefore, ideal refrigerant should have following properties (i) The boiling point should be low. (ii) The condensing pressure should not be more. (iii) Critical temperature should be high. (iv) The latent heat of vaporization should be high. (v) Specific heat of liquid should be low. (vi) It should not have corrosive action. (vii) It should not be flammable and explosive. (viii) It should be non-toxic. (ix) It should be easily detectable for leaks. (x) It should have satisfactory heat transfer coefficient. : Should be easily available at low cost.

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Refrigerator Charging Unit 5. CONSTRUCTION This is a simple arrangement for charging the refrigeration and air conditioning unit. The main feature of this charging set is that the whole assembly is carried on a rectangular base. This is portable device, which can be transferred from one place to another its construction is simple land decorative one. A vacuum pump is fitted on the base plate. In front vacuum pump a vertical rectangular angle set is attached on which spring balanced is attached and the plywood and valve are attached with the help of nut-bolt.

A vacuum pump is mounted for creating the vacuum in the unit. An arrangement of spring balance is to be made for calculating how many amount of gas is filled in unit. For calculating the amounting of the gas

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Refrigerator Charging Unit

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Refrigerator Charging Unit Refrigerant the refrigerant cylinder is attached tom hook of spring balance with the help of into cylinder hanger arrangement. On the front side of this charging set a panel board is fixed for mounting 2 three – way valves and compound pressure gauge. Three charging lines are required for this set. One charging line is joined between the vacuum to connector disconnect the vacuum pump. The second charging line is connected between the cylinder and valve V1 and end of valve V2, which is always open. The third charging line is connected between the refrigeration unit and common end of valve V2 for the purpose of connect or disconnect the unit whenever required. One end of valve V2 is connected to the compound pressure gauge with the help of flare nut.

These two 3-way valve V1 and V2 are

connected with the help of copper tube and flare nut. So this is a simple arrangement of charging set.

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Refrigerator Charging Unit 6. WORKING After assembling it is required to charge the system with refrigerant gas.

Many time charging is necessary after repair and maintenance of the

system. Before charging the system evacuation of system is done. With the help of vacuum pump air in the system is removed and vacuum is achieved. For this purpose the vacuum pump is joined to the common end of valve V1 and connection between cylinder and valve is turned off from cylinder it self. Then turn the valve V2 on for the purpose of removing oxygen and nitrogen from the unit. The vacuum created in the system should be below 300 mm of Hg.

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Refrigerator Charging Unit

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Refrigerator Charging Unit After vaccumisation of the system, the vacuum pump is disconnect immediately with the help of valve V1 by turning it at off position. In this way at the vacuum side connection is off and remaining two connections is on state. The hand shut-off valve is used during change of line. Before charging the system, calculate the amount of gas required for the system. Then place the refrigerate cylinder with the help of cylinder hanger arrangement on the spring balance to refrigerant into evacuated system to exact quantity required. The purging should be done before admitting the gas into system. What amount of pressure present in the system is indicated by compound pressure gauge. The amount of pressure is required inside the system is controlled by valve V2. After completing the process, pinch the process tubes and seal it.

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Refrigerator Charging Unit

7. ADVANTAGES AND APPLICATION Advantages:  The weight of gas and pressure of gas going to the unit is directly measured at the time of charging.  It is multipurpose device.  The connection of vacuum pump to the unit is directly connected with the help of valve and charging line. So separate arrangement is not required for achieving the vacuum in unit.  Simple in construction.  It is portable device, which can be transferred from one place to another.  Less maintenance.  Time is saved due to whole accessories are mounted on one table.  The initial and working cost is less. Application: 

In refrigeration and air-conditioning industries.



In refrigeration shops and laboratories.



It is used for charging of ice plant domestic refrigerator etc.

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Refrigerator Charging Unit 8. HINTS BEFORE CHARGING  Use clean & moisture free drums for transfer & charging purpose.  The system should be evacuated particularly when it is new.  The charging lines must be purged & it must be made sure that all connections are tight air is not drawn in the system with the refrigerant.  The suction pressure may not be allowed to rise above 2 Kg.sq.cm. when charging. The pressure may be controlled with the cylinder valve.  The refrigerant in the liquid from should under no circumstances to the compressor.  The charging lines should not be flexible.  The head pressure must be watched for indications of over charge.

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Refrigerator Charging Unit 9. TESTING OF CHARGING SET (LEAK DETECTION) Before charging the refrigeration unit, the whole system must be tested for the purpose of arising leakage problem. If it is not done, the leakage problem is created & the charging is not done properly i.e. evacuation is not done properly. For this test a high-pressure compressed air is drawn through a charging set. Before entry of the high-pressure compressed air, a soap bubble are placed on v/v port, connection of charging lines & copper tubes & compound pressure gauge for the purpose of to detect the leakage. Then a compressed air is pass through the system if leakage is find, tight the connection with Teflon tape properly. This process is carried out up to the leakage problem is minimized. Then the system is ready form charging. Method Commonly Used For Leak Detection are: 1) Bubble Method 2) Halide Torch Method 3) Electronic Leak Detector 4) Special Method for detection of Ammonia and Sulphur dioxide.

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Refrigerator Charging Unit 1) Bubble Method: This method of leak detection is the oldest one and is Universally used with all the refrigerants. A solution of soap or some other leather forming liquid detergent is applied with the brush over the subjected area or joint. The leaking gas forms bubble, which can be easily been seen. This method of leak detection can only be used when the system has positive pressure. If there is vacuum present in the system, it will pull in the moisture or stop bubble, which will be quite harmful. 2) Halide Torch Method: A carbon element is heated by methyl alcohol or hydrocarbon flame in the halide torch. A rubber tube attached to the refrigerator. A refrigerant going on the tube combines with the Flame to cause Perceptible change in the Flame Color. This method of leak detection is slow and insensitive and in brightly lighted area it is almost impossible to locate small leaks. 3) Electronic Leak Detector: An electronic leak detector is more sensitive and faster responding. The electronic detector contains an internal pump, which draws, and air leaking gas through a probe and hose as the probe is passed over leaking

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Refrigerator Charging Unit joints. A leak-detecting lamp Flashes at this moment. By adjusting a knob on the Electronic detector the magnitude of the leak can also be found. 4) Special Method For detection of Ammonia and Sulphur dioxide: Ammonia leak can be detected by bringing a burning candle of sulphur near the suspected spot. The candle will give a cloud of white smoke if ammonia vapour is present there A solution of hydrochloric acid brought in the Vicinity of ammonia leak will also give white smoke. The moistened strip of Phenol Phalein Paper turns Pink when faintest trace of ammonia vapour comes in contact with it. Presence of sulphur dioxide can be detected by bringing aqueous ammonia near the suspected area. It will give white smoke in the presence of Sulphur dioxide. When no ammonia is available leak may located by the soap bubble or oil test.

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Refrigerator Charging Unit 10. METHODS OF CHARGING By using this set the methods of charging are as follows: There are three methods of charging as given below: 1. Charging thought the suction valve: A small installation, which needs to few kilograms of refrigerant, is usually charged through the suction service valve gauge port. For this method of charging the system is fully evacuated and charged a follows.  Charging line is connected to the suction valve gauge port. Attach a gauge to the discharge valve and open half turn.  The other end of the charging lines us connected to a refrigerant cylinder, which should be standing up right.  The cylinder valve is opened slightly and to flare nut is loosened at the compressor end.

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Refrigerator Charging Unit

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Refrigerator Charging Unit  This operation removes air from the line, when the sound of escaping gas is heard, the nut is tightened.  Suction valve is turned into close the suction line, thus drawing the gas directly from the cylinder by the compressor.  Compressor is started drawing the requisite quantity of refrigerant. The suction pressure should not be allowed to exceed 2 kg/sq.cm. Gauge.  The cylinder valve is closed and the compressor is allowed to run sufficient time to reduce the pressure in charging time to 0 kg/sq.cm. Gauge.  Compressor is stopped and the suction valve is back seated. The charging line is detached and compound gauge attached. The valve is turned in one half turn. The system is thus ready for testing and normal operation. The refrigerant quantity to be charge is often weighted. In that case the cylinder may be on the weighing platform, or suspended from spring scale. The tubing should be coiled and long enough to get true weight. The cylinder may be kept in warm water to quacked the process of charging. 2. Charging through discharge valve: The method is used for certain conditions where it is impossible or impracticable to add refrigerant by the other methods. This is the least used to the three

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Refrigerator Charging Unit methods. The refrigerant is caused to flow by difference in pressure between cylinder and high side. The compressor is not operated while the unit is being

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Refrigerator Charging Unit Charged. In order to save time when charging by this method, it is imperative to weight into an empty cylinder the exact amount of charge required by the system. If this is known, all contents of cylinder transferred. The system is evacuated and following procedure adopted.  The discharge and suction service value are back-seated. The gauge port of each valve is plugged or otherwise kept closed until the valves are wide open.  Compound gauge is attached to the suction valve and the valve is turned in one-half turn. A pipe-to-flare adapter is installed to the discharge valve port and the charging line is connected to the adapter.  The other end of the charging line is connected to the cylinder. The air is removed from line by loosing flare nut. The nut is tightened. The valve A is turned in about half way.  The cylinder is placed bottom side up since the refrigerant will flow into the condenser in liquid form.  After the refrigerant has flowed into the condenser, the discharge valve is back-seated cylinder valve is closed and the charging line is removed. The pressure gauge is attached and the valve is ready for testing and operation.

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Refrigerator Charging Unit 3. Charging through the charging valve: Large machine normally have charging valve located in the liquid line between the receiver valve and the filter or dehydrator. This valve is always located in Ammonia installation and is becoming more popular in other installations requiring large quantities of refrigerants it cuts upon the charge time. The charging refrigerant cylinder acts as received when connected to the charging valve. The refrigerant enters the system in liquid form expanding the liquid control valve before it enters the compressor. This avoids the danger of liquid to enter the compressor and eliminates high vacuum, which may cause the oil to leave the crankcase. The procedure is described below. Refer fig.  System is evacuated and a pressure gauge attached to the discharge valve port and a compound gauge to the suction valve port. Both valves are opened wide and then turned in one half turn so that the gauge will read.  The receiver valve is closed.  Refrigerant cylinder is connected to the charging valve by tubing.

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Refrigerator Charging Unit

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Refrigerator Charging Unit  The cylinder valve is opened slightly and the flare nut is loosened at the charging valve to purge the air from the line. When the sound of escaping gas is he hard the nut is lightened.  The cylinder is tipped to ensure liquid at the valve and then charging and cylinder valves are opened wide.  Compressor is started and the system is charged with required quinsy. When cylinder becomes empty, frost will form on the bottom of the cylinder and the charging line.  After completing the charging close the cylinder valve and run the compressor for sometime to empty the charging line. Then close the charging valve C, and remove the line. The charging valve is capped to prevent leakage.  The receiver valve R is opened, the system is ready for testing and operation.  When charging refrigerant into an ammonia plant using the above method.

It is necessary to lay the cylinders have an internal

gooseneck which makes this necessary. Charging connections for ammonia should be made rigid steel pipe and fittings. For other refrigerants use copper tubing Flexible connections, in the authors opinion are dangerous. N.P.T.N. Achalpur

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Refrigerator Charging Unit 11. CONCLUSION AND MODIFICATION Conclusion: In the end we concluded that by using this instrument we could evacuate and charge the refrigeration and air conditioning system simultaneously. This means that we can save a time by connecting and disconnecting of the charging line. It is used in the charging of refrigeration and air conditioning system in an industries, laboratories etc. Modification: 1. It is possible to weight a refrigerant, which is supplied to the system. 2. From the system we can evacuate and charged the refrigeration and air conditioning system fastly.

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Refrigerator Charging Unit 12. COST ANALYSIS Sr. no. 1. 2. 3. 4. 5. 6. 7 8 9. 10. 11. 12 13. 14. 15

Name of material 3- way valve 2-way valve Copper tube with flare nut Compound pressure gauge with adaptor Charging line Cylinder with gas Angle Vacuum pump Spring balance Plywood Screw Roller Welding Color Other Total

Material Bronze Bronze Copper --

Quantity 2 1 2 1

Cost 360 180 80 205

Rubber R-12 C.I. --Plywood C.I. Rubber ----

3 1 kg 12 kg 1 no. 1 no 10 sq. ft. 34 nos. 4 nos. ----

380 690 210 2200 90 100 15 80 200 120 725 Rs. 5635

BIBLIOGRAPHY 1. Refrigeration and air conditioning S.C Arora , S. Domculwar 2. Refrigeration and air conditioning system. S.L. Gavhale 3. Refrigeration and air conditioning system. S.T. Ghan, R.M. Naphade.

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Refrigerator Charging Unit

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