CONTAINER REFRIGERATION By Chilukuri Maheshwar Marine Engineer (1st Class), MEE, MBA, MPhil (Mgt.) A Witherby Seamanship Publication Preface On 26 April 2006, the shipping industry commemorated 50 years of containerisation. The beginning of the container era was marked when the converted tanker ‘Ideal X ’ set off from Newark to Houston on 26 April 1956, carrying 58 containers in the form of trailer vans, along with 15,000 tons of bulk petroleum. Truck refrigeration began in 1940, when Carrier Inc. marketed its Type 68D truck refrigeration unit. In the early 1960s, Thermo King Inc. unveiled its first ever Reefer Container unit - the ‘NCE’ model. In 1968, the Special Products Division of Carrier Inc. produced the ‘Frostmaster’, the first full front wall or ‘picture frame’ container refrigeration unit. Since then, reefer containers have advanced considerably, undergoing a radical metamorphosis in the process. By 1997 there were 360,000 Reefer Containers in the industry carrying more than 72 million tonnes of cargo. This sum had grown to 105.4 million tonnes by 2004. In spite of the success and longevity of the reefer container industry, the awareness and dissemination of knowledge regarding the operation of reefer container machinery, reefer cargoes and related topics has not kept up with the pace of technology. The increasing number of reefer cargo claims around the world has been attributed to a lack of knowledge among the personnel handling the reefer containers and machinery, both ashore and onboard ship. Reefer cargoes are a high freight cargo; not only are they expensive, it costs twice as much to ship a refrigerated container than a normal one. The conditions required inside a reefer container are demanding and need continual monitoring. Ships’ crews need to be aware of, and correct, any deviation in the temperature of the cargo as soon as possible, since any delay can lead to its deterioration. A sense of urgency is of paramount importance. There are many myths surrounding reefer cargoes, one of them being that the lower the temperature of the cargo the better. In reality this is not true, particularly for chilled cargoes that can be damaged if the temperature is maintained at lower than the set-point. There may also be a considerable communication gap between ship’s staff and shore technicians who use a different terminology that the ship’s staff often struggle to comprehend. The advice and help given by the shore support can be misunderstood, leading to mistakes that can jeopardise the reefer cargo. A ship is responsible for the cargo inside the reefer container from its loading onboard until its discharge. The ship has no control over, or knowledge of, the method of cargo stowage inside the container. The machinery may be functioning perfectly well, the temperatures observed and recorded may be as per the shippers’ instructions, but inside the container the cargo may actually be decaying. The shore loading staff have the responsibility and knowledge to ensure that the cargo is correctly packed inside the container to prevent damage or deterioration. However, in event of an emergency this knowledge is also important for the ship’s staff, as if the cargo has shifted due to rolling and pitching and a hot pocket has formed, it may be necessary to open the container and re-adjust the cargo in order to salvage as much of it as possible. Cargo damage has frequently been observed at the unpacking point even though the correct temperature was maintained during the entire sea voyage. Although the carrier is often blamed for the damage, it is entirely possible that at the container packing location the cargo could have been insufficiently cooled, that - literally - warm (hot) cargoes could have been packed, or that the refrigerated container could be have been left without power for a lengthy period prior to loading onboard ship. Instances have occurred where the reefer container machinery is unrealistically expected to assume the burden of reducing the cargo temperature when it should have been done in cold storage. This book is written from the shipboard operator’s viewpoint, and aims to address some of the limitations of reefer container machinery, dispel the myths surrounding the science of refrigeration, and place facts in their correct perspective. Anyone connected with reefer container operations will also find it of interest. Each chapter is independent and stands alone, it is not necessary to read the chapters in order. Throughout the book, I have referred to reefer machinery manufactured by Carrier Transicold as this is the dominant supplier (with almost 50% market share). Where required I have highlighted key differences between the differing makes of reefer machinery. However, this book is not intended as an instruction manual for reefer machinery manufactured by Carrier Transicold. The basic operation of all reefer machinery is very similar though the components may vary in shape and size. Once the crew are comfortable working with one make of reefer machinery, operation of the products of another manufacturer should not be a problem. All reefer container machinery manufacturers provide instruction manuals and spare part lists and offer basic and refresher training programmes to the personnel of authorised service centres, along with tailor-made training programmes for customers. Many ship owning and management companies also conduct training programmes for their sea going staff. It is recommended that ship’s staff visit manufacturers’ websites, where some excellent resources are freely available. A list of such websites is given in the Bibliography. 1 Basics of Refrigeration ............................................................................................3 1.1 Refrigeration .........................................................................................................................................................................................................3 1.2 Refrigeration and Air Conditioning .............................................................................................................................................................3 1.3 Heat and its Measurement ..............................................................................................................................................................................3 1.4 Specific Heat .........................................................................................................................................................................................................4 1.5 Temperature ........................................................................................................................................................................................................4 1.6 States of Matter ...................................................................................................................................................................................................4 1.7 Vapour and Gas ...................................................................................................................................................................................................4 1.8 Sensible Heat and Latent Heat ......................................................................................................................................................................5 1.9 Saturation Temperature ...................................................................................................................................................................................5 1.10 Fluids and Liquids ..............................................................................................................................................................................................5 1.11 States of Fluids .....................................................................................................................................................................................................5 1.12 Pressure ..................................................................................................................................................................................................................6 1.13 Flow of Heat ..........................................................................................................................................................................................................7 1.14 Refrigerant ............................................................................................................................................................................................................8 1.15 Foundation Pillars of Refrigeration ..............................................................................................................................................................8 1.16 Refrigeration Capacity - Tonnage .................................................................................................................................................................9 1.17 Pressure-Temperature (PT) Chart ..................................................................................................................................................................9 2 The Flow of Refrigerant Through the Components of the Refrigeration System .................................................................................13 2.1 Open Loop and Closed Loop Systems .....................................................................................................................................................13 2.2 Vapour Absorption and Vapour Compression Systems ......................................................................................................................13 2.3 Refrigerant Flow through the Components ...........................................................................................................................................14 2.4 Additional Components ................................................................................................................................................................................18 3 Containerisation and Container Refrigeration ...................................................29 3.1 Introduction .......................................................................................................................................................................................................29 3.2 The Container .....................................................................................................................................................................................................29 3.3 Features of a Container...................................................................................................................................................................................29 3.4 Advantages of Container Transportation.................................................................................................................................................29 3.5 Parts of a Container ..........................................................................................................................................................................................30 3.6 Types of Containers .........................................................................................................................................................................................30 3.7 The Markings on a Container .......................................................................................................................................................................30 3.8 CSC Approval Plate ..........................................................................................................................................................................................32 3.9 Shipboard Orientation of Containers .......................................................................................................................................................32 3.10 Various Stresses on Containers ....................................................................................................................................................................32 3.11 Refrigerated Containers .................................................................................................................................................................................32 3.12 Dual Temperature Container Units .............................................................................................................................................................33 3.13 Identifying a Reefer Container .....................................................................................................................................................................37 3.14 Air Flow within a Reefer Container .............................................................................................................................................................37 3.15 Power Supply for the Refrigeration Machinery .....................................................................................................................................39 3.16 Extra Deadweight, Loss of Volumetric Space and Additional Maintenance Requirements .................................................39 3.17 Stowage of Loaded Reefer Containers .....................................................................................................................................................39 3.18 Running a Reefer Unit in Air Cooled and Water Cooled Modes Simultaneously .......................................................................40 3.19 Loading Reefer Containers onto a Ship ....................................................................................................................................................40 3.20 Evolution of Container Refrigeration.........................................................................................................................................................41 3.21 Commercial Aspects of Reefer Containers ..............................................................................................................................................41 3.22 Comparing Reefer Container Freight and Air Freight..........................................................................................................................41 3.23 Profitability of Containerisation ..................................................................................................................................................................41 4 Types of Refrigerated Cargo .................................................................................45 4.1 Classification of Reefer Cargoes .................................................................................................................................................................45 4.2 Chilled Cargoes ................................................................................................................................................................................................45 4.3 Frozen cargoes ...................................................................................................................................................................................................45 4.4 Clustering of Containers Packed with Chilled or Frozen Cargoes ...................................................................................................46 4.5 Operation of Reefer Machinery for Chilled and Frozen Cargoes .....................................................................................................46 4.6 Packaging Chilled and Frozen Cargoes ....................................................................................................................................................48 4.7 Ethylene Sensitive Cargoes ...........................................................................................................................................................................48 4.8 Chilling Sensitive Cargoes .............................................................................................................................................................................49 Contents 4.9 Recommended Storage Temperatures for Various Refrigerated Products ....................................................................................49 4.10 Value of Reefer Cargoes ................................................................................................................................................................................50 5 Compressors ..........................................................................................................53 5.1 Importance and Working of Compressors...............................................................................................................................................53 5.2 Classification of Compressors ......................................................................................................................................................................53 5.3 Power Consumption by Compressor Type ..............................................................................................................................................57 5.4 Semi-hermetic Reciprocating Compressors ...........................................................................................................................................57 5.5 Scroll Units ..........................................................................................................................................................................................................65 5.6 Shipboard Maintenance of Refrigerated Container Compressors ..................................................................................................68 6 Expansion Valves ...................................................................................................71 6.1 Importance of Expansion Valves .................................................................................................................................................................71 6.2 Types of Metering Devices ............................................................................................................................................................................71 6.3 Types of Expansion Valves ............................................................................................................................................................................72 6.4 The Purpose of an Expansion Valve (TXV) ...............................................................................................................................................72 6.5 Location of the Expansion Valve .................................................................................................................................................................72 6.6 Types of Expansion Valve Used in Container Reefer Machinery ......................................................................................................72 6.7 Expansion Valve Components .....................................................................................................................................................................73 6.8 Operation of the Expansion Valve ..............................................................................................................................................................74 6.9 Periodic Maintenance on the Expansion Valve ......................................................................................................................................75 6.10 Other Types of Expansion Valves ................................................................................................................................................................77 7 Controllers .............................................................................................................81 7.1 Evolution of Controllers ..................................................................................................................................................................................81 7.2 Microprocessor Controller .............................................................................................................................................................................81 7.3 Location of the Controller .............................................................................................................................................................................81 7.4 Components of the Controller .....................................................................................................................................................................82 7.5 Various Makes of Controllers ........................................................................................................................................................................83 7.6 Operation of a Controller ...............................................................................................................................................................................83 7.7 Controller Software ..........................................................................................................................................................................................83 7.8 Upgrading Software ........................................................................................................................................................................................84 7.9 Functions of the Controller ...........................................................................................................................................................................84 7.10 Operation of the Control Circuit ..................................................................................................................................................................85 7.11 Troubleshooting of Controllers ...................................................................................................................................................................87 7.12 Controller Analyser/Tester .............................................................................................................................................................................87 8 Temperature Recording Systems in Reefer Containers ......................................91 8.1 Temperature Measurement ..........................................................................................................................................................................91 8.2 Damaged Cargo – Record of Temperatures ...........................................................................................................................................91 8.3 Evolution of Temperature Recording Systems .......................................................................................................................................91 8.4 Downloading and Interpretation of Recorded Data .........................................................................................................................106 8.5 Looking at the Future of Recording Systems ........................................................................................................................................107 9 Controlled Atmosphere Systems ........................................................................111 9.1 Basic Concept ...................................................................................................................................................................................................111 9.2 Respiration Rates of Different Products..................................................................................................................................................111 9.3 Timeline of Controlled Atmosphere Systems .......................................................................................................................................111 9.4 Conservation of Perishable Products Through Controlled Atmosphere ....................................................................................111 9.5 Variation of Respiration with Oxygen Content ...................................................................................................................................112 9.6 Applications of Controlled Atmosphere (CA) Systems .....................................................................................................................112 9.7 Various Models of CA Systems ...................................................................................................................................................................113 9.8 Safety ..................................................................................................................................................................................................................119 10 Humidification Systems ......................................................................................125 10.1 Variation of Humidity Inside a Reefer Container Over the Course of a Voyage ......................................................................125 10.2 Effect of Reduced Humidity on the Cargo .............................................................................................................................................125 10.3 Solution ..............................................................................................................................................................................................................125 10.4 Operation of the Humidification System ...............................................................................................................................................125 10.5 Components of Humidification System .................................................................................................................................................126 10.6 Pre-Trip Requirements ..................................................................................................................................................................................126 10.7 Post-Trip Requirements ................................................................................................................................................................................126 10.8 Interdependence of Refrigeration, Humidification and Controlled Atmosphere Systems .................................................127 10.9 Benefits of Humidification Systems ........................................................................................................................................................127 10.10 Dehumidification Mode ..............................................................................................................................................................................127 10.11 Bulb Mode ........................................................................................................................................................................................................127 10.12 Snap Freeze Operation .................................................................................................................................................................................128 10.13 Humidification Systems-Summary ...........................................................................................................................................................128 11 Refrigerants .........................................................................................................131 11.1 Refrigerant ........................................................................................................................................................................................................131 11.2 Refrigerants; a Timeline ................................................................................................................................................................................131 11.3 Generations of Refrigerants ........................................................................................................................................................................131 11.4 Classification of Refrigerants ......................................................................................................................................................................132 11.5 Desirable Properties of a Refrigerant ......................................................................................................................................................134 11.6 Which Refrigerant is Suitable? ...................................................................................................................................................................134 11.7 The R-numbering System ............................................................................................................................................................................134 11.8 Global Warming and Ozone Depletion..............................................................................................................................................................134 11.9 The Montreal Protocol ..................................................................................................................................................................................135 11.10 Refrigerants Used in Container Refrigeration ......................................................................................................................................136 11.11 Refrigerant Colour Code System ..............................................................................................................................................................136 11.12 Refrigerants and Oil .......................................................................................................................................................................................136 11.13 Migration of a Refrigerant ...........................................................................................................................................................................137 11.14 Refrigerant Charge .........................................................................................................................................................................................138 11.15 Refrigerant Recovery Procedure ...............................................................................................................................................................139 11.16 Changeover of Refrigerants .......................................................................................................................................................................140 11.17 Threshold Limit Value (TLV) ........................................................................................................................................................................141 11.18 Impact of Legislation on the Shipping Industry ..................................................................................................................................141 11.19 The Future of Refrigerants ...........................................................................................................................................................................142 12 Maintenance of Reefer Container Machinery ...................................................147 12.1 Periodic Maintenance on Reefer Container Machinery ....................................................................................................................147 12.2 Who Carries Out the Periodic Maintenance? ........................................................................................................................................147 12.3 Exclusivity of the Authorised Service Provider ....................................................................................................................................147 12.4 Approving Repairs .........................................................................................................................................................................................148 12.5 Pre-Trip Inspection (PTI) ...............................................................................................................................................................................148 12.6 Auto PTI ..............................................................................................................................................................................................................148 12.7 Reefer Container Equipment Maintenance Procedures ...................................................................................................................148 13 Reefer Cargo Losses ............................................................................................157 13.1 Poor Information Transfer and Communication..................................................................................................................................157 13.2 Pre-shipment Failure to Provide Suitable Conditions or Information .................................................................................................160 13.3 Ship’s Failure to Maintain Necessary Conditions .................................................................................................................................162 14 The 360 Quality Code and Zero Damage Concept for Reefer Cargoes ............169 14.1 The 360 Quality Code ....................................................................................................................................................................................169 14.2 What is Zero Damage? ..................................................................................................................................................................................170 14.3 The Reefer Cargo Supply Chain .................................................................................................................................................................170 14.4 Equipment used in Zero Damage Control Process .............................................................................................................................171 14.5 Pre-Loading Activity ........................................................................................................................................................................................................................173 14.6 Local Zero Damage Procedure ..................................................................................................................................................................174 14.7 Checkpoint Vessel-In .....................................................................................................................................................................................176 14.8 The Agent’s Role .............................................................................................................................................................................................178 14.9 Cargo Care During the Voyage ..................................................................................................................................................................179 14.10 Discharging the Cargo ..................................................................................................................................................................................180 14.11 Checkpoint Vessel – Out ..............................................................................................................................................................................180 14.12 Checkpoint Terminal – Out .........................................................................................................................................................................181 14.13 The Future? .......................................................................................................................................................................................................181 15 Guidelines for Carriage of Live Cargo Onboard In Reefer Containers.............185 15.1 Loading ..............................................................................................................................................................................................................185 15.2 Carriage Guidelines ........................................................................................................................................................................................186 15.3 Safety Guidelines ............................................................................................................................................................................................189 15.4 Documentation ...............................................................................................................................................................................................190 15.5 Actions in Case of Dispute ..........................................................................................................................................................................191 16 Worldwide Containerised Reefer Cargo Trade ..................................................195 16.1 Trends in Refrigerated Cargo Trade and Forecast ...............................................................................................................................195 16.2 Growth of Reefer Containers over Conventional Shipment ...........................................................................................................196 16.3 Commodity Trade ...........................................................................................................................................................................................196 16.4 Integral vs. Insulated Containers ...............................................................................................................................................................196 16.5 Trends in Reefer Container Production...................................................................................................................................................196 16.6 Replacement Container Stock ...................................................................................................................................................................197 16.7 Capacity and Production of Reefer Containers by Region ..............................................................................................................198 16.8 Cost–Price Issue ..............................................................................................................................................................................................198 16.9 Share of Container Trade and Plug Capacity of Various Carriers ...................................................................................................200 16.10 Trends in the Container Ship Fleet ...........................................................................................................................................................200 16.11 Trends in Age and Size of Reefer Container Ships ..............................................................................................................................200 16.12 Trends in Increasing Reefer Container Carrying Capacity of Ships ....................................................................................................................201 16.13 Classification of Reefer Container Ships .................................................................................................................................................202 17 Diagnostics and Trouble-Shooting ....................................................................207 17.1 Refrigerant .......................................................................................................................................................................................................207 17.2 Components of the Refrigeration Cycle ................................................................................................................................................210 17.3 Containers .........................................................................................................................................................................................................214 17.4 Cargo ...................................................................................................................................................................................................................217 17.5 Partlow Chart Exercise ..................................................................................................................................................................................222 17.6 Electrical System .............................................................................................................................................................................................224 Appendices ....................................................................................................................................................................................................233 1. APL Container Loading Checklist: APL ....................................................................................................................................................234 2. Carrier Microlink 2 Microprocessor Checkout Sheet: Carrier Transicold .....................................................................................235 3. Reefer Bill of Lading (2 pages): Japan Shipping Exchange(JSE) .....................................................................................................236 4. Reefer FCL Shipping order/Booking Note: Hyundai Merchant Marine (HMM) .......................................................................238 5. Letter of Indemnity - Reefer Loading Discrepancy Report: Hyundai Merchant Marine (HMM) ........................................239 6. Reefer Cargo Manifest: ZIM Lines .............................................................................................................................................................240 7. Reefer Container Pre-Trip Inspection Report: Eastern 1961 ............................................................................................................241 8. Reefer Pre Trip Inspection Report: Tech-Tainer Services (Eastern 1961) .....................................................................................242 9. Reefer Pre Trip Inspection Report: Dolphin Marine Enterprises Pvt. Ltd. ...................................................................................243 10. Pre Trip Inspection Report 20 ft and 40 ft Reefers: CRONOS ...........................................................................................................244 11. Reefer Repair Estimates Form: Dolphin Marine Enterprises Pvt. Ltd...........................................................................................245 12. Estimates Form for Reefer Container: CEDEX .......................................................................................................................................246 13. Reefer Container Daily Logsheet: (Anglo Eastern Group) ................................................................................................................247 14. Reefer Container Monitor Log: Fleet Management Limited ..........................................................................................................248 15. Reefer Cargo Temperature Log for Reefer Vessels: Fleet Management Limited ......................................................................249 16. 134a Conversion Check Out Sheet: Carrier Transicold ......................................................................................................................250 17. Refrigerated Container OFF/ON Hire Inspection Report: TRANSAMERICA ...............................................................................251 18. Stevedore Damage and Notice of Liability: Anglo – Eastern ..........................................................................................................252 19. Container Damage Report and Notice of Liability: Anglo – Eastern (2 Pages) .........................................................................253 20. Departure Check List for Container Vessels: Fleet Management Limited ..................................................................................255 21. Reefer Loading Instructions: GESeaco ...................................................................................................................................................256 22. Temperature Conversion Table ..................................................................................................................................................................257 23. Properties of Commonly used Refrigerants ..........................................................................................................................................257 24. R Numbering of Commonly used Refrigerants ....................................................................................................................................258 25. Colour coding of refrigerants .....................................................................................................................................................................258 26. Reefer Container Terminology ...................................................................................................................................................................259 27. Fresh Air Exchange Rate Conversion Table ............................................................................................................................................259 28. Reefer Commodity Handling Table ..........................................................................................................................................................261 29. Recommended Storage Temperatures for Various Refrigerated Products: Dr Yves Wild .....................................................268 Abbreviations ....................................................................................................................................................................................................269 Glossary ....................................................................................................................................................................................................271 Bibliography ....................................................................................................................................................................................................283 Index ....................................................................................................................................................................................................285 About the Author ....................................................................................................................................................................................................293 12 Maintenance of Reefer Container Machinery This chapter examines the maintenance procedures necessary to ensure the trouble-free operation of reefer container machinery while onboard. 147 Periodic 12.1 Maintenance on Reefer Container Machinery It is recommended that a maintenance procedure be carried out on reefer container machinery prior to each loading of cargo. This is not a planned interval exercise, but does ensure the correct operation of other related machinery onboard the ship due to the following reasons: Unpredictable 12.1.1 Schedules A reefer container running schedule is not fixed or predictable. A reefer container may leave its home port, for example New York, and only return after 10 to15 years. It may never return to its home port at all but instead travel to various parts of the world carrying reefer cargo whenever and wherever it is available. Although the manufacturers specify standard routine maintenance procedures for their service providers around the world, due to local conditions, availability of spares, urgency of the container and local quality anomalies, the work carried out is not of a uniform standard. Unmonitored 12.1.2 Running Hours of Components Few components of the reefer container machinery, other than the compressor, have monitored running hours. For those not fitted with a running hour meter, the length of service is not known: for example, it is not known when the expansion valve was last changed or when the oil or refrigerant was renewed or topped up. It is good practice for these procedures be routinely noted. Improper 12.1.3 Maintenance of Records - Log Books Most reefer container owners provide a logbook in a pocket on the control panel door along with the circuit diagrams. The log book’s use is not monitored and often the last entry may have been made two or three years ago, or the logbook has been lost and not replaced. From the container owner’s point of view, the log book is not considered very important, so no record is kept to indicate when a maintenance procedure is performed on the machinery. Who Carries 12.2 Out the Periodic Maintenance? Authorised service providers are responsible for carrying out reefer container machinery maintenance. Before any loaded passage, the machinery must undergo a thorough and detailed inspection and all maintenance checks must be carried out as stipulated by the manufacturer; the desired result being maintenance free carriage of the reefer cargo. These maintenance procedures are expected to be carried out by shore staff (an authorised service provider, ASP) that have service contracts with the container owners (or the agents). The ASP’s technicians are trained by the manufacturer and their skills are upgraded through frequent training programmes and workshops. Most manufacturers stipulate that 80% of the technicians should have undergone one of their training programmes and that 50% should have attended upgrading programmes in the last three years. The manufacturer’s authorisation indirectly guarantees the quality of the job carried out. An ASP is also responsible for carrying out warranty jobs on reefer container machinery, free of charge to the customer on a priority basis, including the replacement of spares on behalf of the manufacturer. In return, the service provider receives a discount on the cost of spares. An ASP is also expected to keep a minimum inventory of the spare parts stipulated by the manufacturer. The aim is to provide prompt and efficient service to the customer and maintain the manufacturer’s reputation in the market. Exclusivity of the 12.3 Authorised Service Provider Service providers may have authorisation from any number of manufacturers such as Carrier, Thermo King, Daikin or Mitsubishi. ASPs do not sell reefer container machinery, they only service it. Spare parts are replaced as necessary. Regardless of the make of the container requiring maintenance, the service provider has to be able to provide the necessary service using the particular manufacturer’s spare parts. The service provider signs contracts with different competing container owners (or their agents) for storage space and servicing, repairing and preparing the reefer containers. 148 • Container Refrigeration Approving Repairs 12.4 Once a reefer container has been unpacked at the consignee’s premises, the owner’s agent sends it to the ASP’s depot, where a preliminary inspection is carried out and a report submitted to the owner’s agent highlighting any major visible defects. As soon as possible, a detailed physical and operational inspection is carried out by the service provider. A report including a cost estimate is then submitted to the owner’s agent. Authorisation for repairs may be granted subject to the agent’s financial authority to accept the estimate and authorise repairs up to a certain limit. The service provider carries out only the repairs authorised by the agent. The container is stored in the storage depot until needed for the next consignment of cargo. Once a cargo is found by the agent, notice is given to the service provider to carry out the final inspection of the container and prepare it for carriage of the specified cargo. This may involve the provision of additional fittings inside the container. When the container is fully prepared for a specified cargo as per the shipper’s requirements, it is inspected by a surveyor appointed by the shipper and then taken to the packing area. Reefer cargo is usually packed in a refrigerated loading bay where the temperature is the same as that required by the cargo during the passage. After loading the container goes to Customs, and then to the port where it is kept at a site with reefer points. Electric power is connected as soon as possible to keep the machinery running and maintain the temperature. The service provider is usually contracted to supervise the plugging, unplugging and running of the reefer machinery during the waiting period until it is finally connected to a ship’s power supply. When the designated ship arrives and is ready for loading, the reefer container is unplugged and loaded into its allocated slot on the ship. As soon as possible it is connected to the ship’s power supply to keep the reefer machinery running. Most container owners have comprehensive check lists to ensure that both the requirements of the consignee and the cargo are met. Pre-Trip Inspection 12.5 (PTI) A ‘trip’ is any loaded passage of a reefer container carrying cargo. It should be differentiated from a ‘voyage’, which usually means an outward or inward journey. As it is impossible to count the number of loaded passages of the container, these trips are not marked. The reefer machinery’s electronic controller keypad has a function that electronically marks the beginning of a trip. A pre-trip inspection is the comprehensive physical inspection and detailed operational check carried out ashore by the service provider before the start of every loaded passage (trip). This ensures that the reefer machinery operation will be trouble-free for the duration of the trip. Auto PTI12.6 The operational part of the pre- trip check, carried out using the controller keypad, is known as the auto pre-trip inspection (PTI). Each component is checked for its correct values and the balance of various key parameters such as current draws. The components are checked in a step by step sequence for a specific period of time before determining if the parts are satisfactory. Auto PTI 1 (short) takes •approximately 20 minutes and can be performed on loaded containers without affecting the cargo. It consists of a series of unit functionality tests of the various operating circuits of the controller. Auto PTI 2 (long) takes more •than 3 hours and includes comprehensive operational tests including temperature pull down tests. A long PTI should not be performed on loaded containers as it is not safe for the cargo to be without cooling for such a long period of time. This is particularly true for chilled cargoes as damage can occur due to the accumulation of heat. There is also a facility for performing individual tests of the PTI sequence. This is a useful fault-finding tool. A defective or poorly performing component is indicated by a failure in the PTI sequence. A satisfactory component is indicated by a pass. Although an auto PTI is performed by the terminal operator before the cargo is loaded, it can also be performed onboard by the ship’s staff in the event of a problem with the performance of the refrigeration machinery. This will help to quickly identify any defective component in the refrigeration circuit. The sequence (Table 12.1) shows the codes appearing on the display menu as the tests are carried out in the auto PTI 1 and auto PTI 2 checks. Each individual test in the auto PTI sequence has its own requirements, test conditions and pass/fail criteria. In addition to auto PTI 1 and auto PTI 2, Carrier Transicold has recently introduced a 2 hour-long auto PTI 3 check, which starts at P1-0 and terminates at P8-2. Similar to an auto PTI 2 sequence, auto PTI 3 cannot be undertaken when the container is carrying perishable cargo that could be damaged by the amount of time without cooling. The auto PTI 3 check has the advantage of being completed more quickly than an auto PTI 2, as the tests for frozen cargo are not carried out. Reefer Container 12.7 Equipment Maintenance Procedures The inspection procedure (the example here is Carrier machinery), is as follows: a. A two step Physical Inspection• Front of the unit• rear of the unit. b. Operational inspection The physical and operational inspections will take at least six hours to complete if carried out diligently. This does not include the additional time necessary for replacing components or painting etc. Figure 12.1 Connecting up a reefer container 149 Figure 12.2 Typical areas of oil leakage Physical Inspection12.7.1 Front of the unit12.7.1.1 a. Leakage of Fluid Check for refrigerant leaks •look for evidence of oil leaks in: •- compressor joints- cylinder heads- HPS (high pressure switch) connection- piping connections- oil pump cover- base plate. b. Components prone to damage from corrosion Rinse these areas, including •the condenser coil, with low pressure water maintenance of painted •surfaces, for example the compressor and receiver examine remote monitoring •and interrogation receptacles check compressor mounting •plate for corrosion and damage. Figure 12.3 Components prone to damage from corrosion c. Components inside control box. Check for the following in the control box: Signs of overheating, •corrosion, moisture ingress and damage loose wires and insecure wire •harnesses and connections wiring diagrams and •schematics should be in place. Figure 12.4 Components inside control box Table 12.1 Showing the codes on the display menu 150 • Container Refrigeration d. Condenser fan and motor. Examine the condenser •motor fan blade for cracks and corrosion check for correct condenser •fan positioning in the venturi examine condenser motor for •the following: free movement of •bearings corrosion •signs of overheating. • Figure 12.5 Condenser fan and motor e. Defrost drain tube and suction modulation valve (SMV). Examine the condenser coil •straighten any fin damage •using a fin comb check for leaks •check for corrosion •examine drain tube •examine SMV •megohm test and resistance •check check that the valve stem has •not seized due to corrosion. Figure 12.6 Defrost drain tube and suction modulation valve f. Suction solenoid valve (SSV) and filter drier. Examine SSV for: •excessive corrosion •physical damage •megohm test and resistance •check inspect filter drier •inspect water cooled •condenser (if fitted) g. Quench valve and moisture indicator. Check for any physical damage, leaks or corrosion in: Electrical quench valve (R-12 •Units) expansion quench valve •(R-134a Units) pressure relief devices •moisture indicator. • h. Partlow recorder. Examine Partlow recorder (if •fitted) check box hinges for •corrosion or breakage check clock operation •check that the chart is being •correctly marked wind the clock. • i. Power cables, plugs and door gaskets. Examine the power cables •continuity check •megohm test •check plug for: •- burnt or pitted pins- correct fitting of the gland seal and strain relief - cracking/damage examine doors and panel •gaskets. j. Structural Integrity, instruction labels and plates. Check for proper torque •of the evaporator motor mounting brackets instruction labels and •placards for example model/ serial plate and warning labels inspect structural integrity of •the unit. Figure 12.7 Suction solenoid valve and filter drier