Machines and apparatus refrigeration units placed in such a way as to ensure their normal maintenance and repair.
Maintenance of a refrigeration unit consists of preparing it for operation, starting it up, regulating the supply of refrigerant to evaporation system, caring for the refrigeration unit during operation, stopping and shutting down machines and devices, observing safety regulations, keeping machines and work areas clean and in good working order, as well as filling out the necessary reporting documentation.
The entry on duty of shift personnel begins with checking the entries in the refrigeration station operation log, and ends with monitoring temperatures at key points refrigeration cycle and checking the operation of refrigeration station equipment.
Both shifts - the handing over and the receiving - sign for the delivery and acceptance of the shift in the journal.
The duty personnel periodically check the quantity and density of brine, the water supply to the condensers, the serviceability of emergency ventilation, the availability of necessary spare parts, materials and tools, and personal protective equipment. Special attention should be given to checking the condition of the rubbing parts of compressors and pumps, operation oil system, valves and seals.
For the convenience of maintenance personnel, inspection lights or other devices are installed on the cooling water pipelines to monitor the flow of water.
In various places of the refrigeration unit, there are also sockets for devices required both for constant monitoring of the operation of the unit and for periodic testing. Pressure gauges, thermometers, ammeters and others measuring instruments installed so that when starting the installation they are in the field of view of the driver and his assistant.
Automatic control valves are usually duplicated by manual ones. This allows you to continue producing cold if some of the automatic control devices fail.
Medium and large refrigeration units mainly operate with a manual starting system. Their technical operation is quite complex and requires deep knowledge from the operating personnel. physical foundations obtaining cold, designing machines, apparatus, instruments, fittings and rules for handling them.
To facilitate the work of personnel, pipeline diagrams, equipment layout plans, information about the main parameters of refrigeration units, consumption rates of refrigerant, oil, electricity, safety posters, and graphs are posted in the engine rooms of refrigeration stations. preventive examinations and repairs.
In order to orient service personnel in branched pipeline diagrams, they are painted in conventional colors. The most commonly used colors are:
for refrigerant pipelines: discharge - red, liquid - yellow, suction - blue;
for brine pipelines: pressure - green, return - brown;
for water pipelines: pressure - blue, return - purple.
If there are several cold parameters, conditional rings are also applied to the painted pipelines, indicating which machine this pipeline belongs to.
Efficient and reliable operation of any refrigeration unit depends not only on good technical condition equipment, but also from its proper operation. Direct supervision of the operation of the equipment is carried out by drivers, their assistants, operator operators, mechanics on duty and electricians subordinate to the shift supervisor of the refrigeration station.
Their main task is to maintain given parameters operation of refrigeration machines with the lowest consumption of energy and operating materials and strict compliance with safety regulations.
To successfully complete the tasks facing operating personnel, it is necessary to:
high quality and serviceability of equipment;
provision of control and measuring instruments;
availability of spare parts, tools and repair devices;
availability of refrigerant, coolant, water, lubricating oils, instrumentation air, operating materials and energy resources;
correct filling of systems with refrigerant and coolant; absence of contamination on heat transfer surfaces; timely prevention and repairs; maintaining a shift log to identify violations of the operating schedule;
highly qualified service personnel.
The operation of refrigeration units is regulated special instructions. Failure to comply with them may result in violation technological process consumers of cold and increased energy consumption to obtain cold.
The sequence of individual operations during starting and stopping and the maintenance procedure depend on the design and operational features refrigeration unit, which must be reflected in the maintenance instructions.
This chapter discusses the basic rules and techniques for operating the most common types of large refrigeration units, which in each individual case must be clarified in accordance with the start-up instructions of the equipment manufacturers. Having studied these techniques, the future driver or operator will be able to master the procedure for starting, regulating and stopping refrigeration units of any system.
Persons who have reached the age of eighteen, have passed a medical examination and have a certificate of completion of training in their chosen specialty are allowed to operate industrial refrigeration units.
Operating personnel must know well and strictly follow the rules and instructions for the operation and repair of equipment and devices of refrigeration stations. Engine rooms of refrigeration stations are the workplace of the driver and his assistant. The pumping and equipment departments are serviced by operators who are subordinate to the driver and coordinate all their actions with him.
Refrigeration station personnel annually pass exams of the qualification commission. The exam results are documented in a protocol. Persons who pass these exams are issued special certificates.
Control questions
1. What tasks are assigned to the operating personnel of refrigeration units?
2. List the conditions necessary for successful work refrigeration unit.
3. Tell us how to fill the system with ammonia and freon?
4. How is brine prepared?
5. Tell us about preparations for starting up the refrigeration unit.
6. How do you start a refrigeration unit with piston compressors and turbocompressors?
7. List the signs of normal operation of a piston compressor.
8. Tell us about compressor lubrication.
9. How is the operation of a compression refrigeration unit regulated?
10. What temperature changes should accompany the normal operation of an ammonia refrigeration unit?
11. Explain the procedure for stopping a compression refrigeration unit.
12. What do you know about maintenance procedures for evaporators and condensers?
13. What causes deterioration in heat transfer in the evaporator and condensers?
14. Tell us about preparations for the launch of freon turbo units.
15. What signs characterize the normal operation of a turbo-refrigeration freon unit?
16. Tell us about the operating features of propylene turbine units.
17. How are absorption refrigeration machines filled with ammonia-water solution?
18. Explain the starting and stopping of an absorption chiller.
19. Tell us about the operation of centrifugal pumps.
20. What causes corrosion of refrigeration equipment?
21. How does tread protection work?
 |
|
 |
 |
 |
 |
 |
 |
 |
 |
Regular maintenance is essential for longevity refrigeration equipment in various areas of production and public services.
The Ecolife company provides professional maintenance of refrigeration equipment in Moscow and the Moscow region. We will ensure the stable operation of your equipment and, as a result, the entire enterprise.
You will be guaranteed against sudden stoppage of refrigeration equipment due to mode failure, malfunctions, wear of parts, clogging and contamination of units.
The list of work on servicing refrigeration equipment depends on specific type technology, operating features and design.
The cost is calculated individually depending on the form of cooperation. General prices are available upon request.
We work throughout Moscow and Moscow Region with visits to equipment. The guarantee of our work is the use of high-quality components and tools and the professionalism of our employees at an affordable cost. In our work we use low-aggressive detergents"Frionett" and "Convotherm", permitted in the Russian Federation.
We enter into an agreement with clients for the maintenance of refrigeration equipment, in a special appendix of which a list of works is prescribed with all measures to maintain the equipment in working order.
Each item on the list is agreed upon with the client; the type of contract depends on the long-term cooperation, the type and complexity of the equipment.
We offer three standard contracts:
1. One-time service agreement
2. Permanent service agreement
3. Agreement scheduled maintenance(annual service with schedule of events)
Includes diagnostics, troubleshooting and preventive maintenance for the further functioning of the equipment.
First, a preliminary visit of specialists to the site, drawing up an estimate with a list of works and agreeing on deadlines.
Payment is made for activities carried out within the framework of the contract after signing the acts.
1. Inspection and visual assessment external state, configuration and functionality
2. Checking and adjusting hinges and locks
3. Cleaning the frame, compressor, air condenser
4. Pulling threaded connections
5. Check for refrigerant leakage,
6. Checking the thermal insulation of the refrigeration circuit
7. Checking electrical networks, contacts and connections
8. Elimination of existing faults, refueling the circuit and replacing worn parts if necessary
9. Testing operating modes
10. Entering data into the journal
Upon completion of the work, the company employee makes recommendations for further operation of the equipment.
During the work, the list of services can be adjusted if malfunctions are detected during the inspection process.
The agreement on permanent cooperation is concluded for an agreed period, during which our specialists undertake all work to maintain the condition of the equipment at fixed rates. An exact work schedule is not established; all activities are carried out as necessary or at the request of the client. Payment is made upon completion of the work each time the work is completed.
Planned annual maintenance includes a set of regular measures according to a set schedule. In agreement with the customer, specialists regularly visit the work site, assess the condition of the equipment and take all necessary measures for further operation in the required mode.
Regular maintenance will help to identify serious problems in time and take action. preventive measures to eliminate them. Timely inspection can prevent sudden breakdown and shutdown of equipment. All work is carried out strictly according to the planned schedule, which includes a payment schedule.
| Periodicity | List of maintenance work for refrigeration machines | Additional list of works for pumping station refrigeration unit |
| Monthly |
Visual inspection, |
Control of corrosion processes in the main components of mechanisms, |
| Quarterly |
Control of air condensers, |
Coolant refueling and analysis, |
| Once every six months |
Condition monitoring and cleaning of capacitors, |
|
| Annually |
Inspection of internal cavities and fan bearings, |
Cleaning all filters, |
| Once every 2 years | . replacing compressor oil | |
| Once every 3 years | . refilling the coolant and cleaning the entire system |
Each client with whom we have entered into an agreement is provided with additional services, including free consultations and recommendations on the operation of refrigeration equipment. Our clients also receive a discount on spare parts and components for refrigeration equipment.
To get detailed information and request personalized service, you can call us by phone or fill out the form on the website. Our specialists will contact you as soon as possible and provide detailed advice on issues of interest.
Target technical operation refrigeration unit - establishing and maintaining specified temperature and humidity conditions in refrigerated rooms. The main task is to ensure reliable, trouble-free and safe operation of all refrigeration equipment at minimum costs for the production of artificial refrigeration.
Proper organization technical operation of the refrigeration unit must meet the requirements:
reliability and durability of the refrigeration equipment in use;
safety and trouble-free operation.
The costs of producing cold, associated with saving electricity, labor, water, and operating materials, should be minimal.
An important condition Normal operation of a refrigeration unit requires the presence of specially trained personnel. Personnel servicing the refrigeration unit must follow technical documentation for a refrigeration unit, production instructions for maintenance of the entire installation as a whole, as well as its individual units and elements.
With economical safe operation refrigeration installation must be observed optimal mode its operation, equip the installation with instrumentation, automatic control and protection devices, correctly fill the system with refrigerant, keep the heat transfer surfaces of condensers and evaporators clean, carry out scheduled preventive maintenance of refrigeration equipment in a timely manner, keep a daily log of the refrigeration unit and draw up technical reports.
At trade enterprises and Catering Refrigeration equipment is serviced by mechanics from specialized refrigeration equipment plants. Maintenance includes inspections carried out once a month with preventative work and necessary minor repairs, troubleshooting that may occur, daily checking the operation of the refrigeration unit.
The scope of maintenance depends on the type of machine, the installation layout and the degree of automation.
Conclusion
Today, manufacturing technologies for refrigeration units are at a very high level. The development of new models of refrigeration units today has even affected the field of microelectronics. Refrigeration machine production technologies and digital computer technologies were also not spared.
The use of computer-controlled refrigeration units in everyday life significantly adds convenience to their operation, saves time, and computer monitoring of the condition of the unit components supports its more reliable and safe operation for many years.
The use of computer-controlled refrigeration units in production increases production efficiency, provides reliable temperature control, thereby reliably preserving raw materials and ensuring minimal losses.
Perhaps the main disadvantage of such installations is the complexity and high price repairs electronic parts computer control. In addition, electronic components require special conditions operation. Another disadvantage is that computer-controlled refrigerators are quite expensive, but the savings on minimal losses of raw materials during storage in production fully justify the cost of the units.
Another important problem is the lack of specialists to service such equipment. But most enterprises in Russia invite specialists from abroad to service imported refrigeration units, since most of the digitally controlled refrigerators are supplied from abroad.
Unfortunately, few such refrigerators are produced in Russia, or they are produced, but under the license of foreign companies, respectively, such units enter the market under the brand of a foreign company.
Therefore, it is necessary to develop in Russia the development and production of refrigerators and refrigeration units with digital control and create new technologies for their production so that Russian refrigeration units become competitive in the world market.
Related information:
Refrigeration equipment put into operation in public catering and trade enterprises is usually serviced, repaired and adjusted by employees of repair and installation plants (shops) under a contract.
At enterprises operating refrigeration equipment, each type or group of equipment is assigned an operational, laced and numbered log, in which the act of putting the equipment into operation is filed. During operation of the equipment, a mechanic at an enterprise or repair and installation plant records in a logbook information about all work carried out to service the equipment, as well as about instructions to operating personnel on operating rules. All the mechanic’s entries in the logbook are checked and signed by the enterprise administration. The journal must be kept by the director of the enterprise or his deputy.
If there is an agreement for the maintenance of refrigeration equipment between the repair and installation plant and the enterprise, it is assigned to a specific team of mechanics. The mechanic carries out equipment maintenance work according to the plan. The frequency of this work depends on general level maintenance and operation of refrigeration equipment. The mechanic also performs preventive maintenance work. The scope of this work includes inspecting the refrigeration machine system to identify freon leaks and eliminate them, cleaning equipment from dust and dirt, tensioning transmission belts, checking grounding (or grounding), monitoring the temperature conditions of refrigeration equipment, regulating automation devices, etc.
The mechanic instructs personnel on the design, operating principle of the equipment and operating rules. At emergency situations or the refrigeration machine stops for a reason that cannot be eliminated by the maintenance personnel, a mechanic is called out.
Operated refrigeration equipment must be kept in proper sanitary condition. To do this, refrigeration equipment should be washed at least once a week. warm water with soap, then rinse with warm clean water, wipe dry with a cloth and leave open overnight for ventilation. External chrome-plated and nickel-plated parts of refrigeration equipment must be wiped daily with rags moistened with Vaseline technical oil.
Maintaining product quality while cold storage largely depends on the sanitary condition of the cells. Therefore, it is necessary to periodically carry out microbiological monitoring of the chambers to timely identify the degree of their contamination with molds. Chambers contaminated with mold should be disinfected according to " Sanitary rules for enterprises of the refrigeration industry."
Floors in cells and corridors, staircases and elevators for ascent food products from refrigerators to industrial premises They are cleaned as they become dirty, but at least once per shift. Oily and slippery floors and doors in cold rooms with above-zero temperatures, in corridors and staircases washed with a hot solution of soap or lye and wiped dry.
To clean refrigeration equipment, use special equipment and store it separately from equipment used for cleaning other premises and equipment.
To eliminate foreign odors in refrigeration chambers, they are periodically ventilated or treated with ozone.
The shelf life of products is established in accordance with approved standards.
Responsibility for compliance with technical and sanitary rules storage of food products is assigned to the head of the enterprise. Monitoring compliance with sanitary rules for storing food products is carried out by the State Sanitary Inspection authorities and departmental sanitary services.
To save High Quality When storing food products in commercial refrigeration equipment (collapsible chambers, cabinets, counters and display cases), it is necessary to ensure strict adherence to the storage temperature conditions. Refrigeration equipment can be loaded with products only after the required storage temperature has been reached. Counters, cabinets and display cases are not designed to refrigerate food and should only be loaded with refrigerated food. Use of refrigeration commercial equipment for cooling hot dishes or drinks is not allowed. Loading of refrigeration equipment and placement of products in it must be carried out in accordance with technical requirements. When loaded correctly, the products are placed evenly over the entire area of the shelves so that they do not touch the walls of the refrigerated chamber and there is a passage for air between them. If equipment is loaded incorrectly or overloaded with products, air circulation conditions deteriorate, which leads to uneven cooling and heating. inner layers. It is prohibited to cover the grid shelves of refrigeration equipment with paper, cloth or other materials that impede the circulation of cooling air. It is not allowed to place products close to the evaporator of the refrigeration machine, minimum distance- 40 mm.
Maintaining the required temperature in the cooled chamber depends on the operating conditions of the refrigeration machine evaporator. During operation of the refrigeration machine, a layer of snow freezes on the walls of the evaporator, the thickness of which determines the operation of both the refrigeration machine and all equipment. When a layer of snow of 5-7 mm freezes, the channels between the evaporator fins become clogged, the process of heat exchange between air and refrigerant sharply deteriorates, which leads to an increase in the temperature in the cooled chamber, an increase in electricity consumption and the operating time coefficient. Therefore, it is necessary to defrost the snow coat from the evaporator in a timely manner. Thawing a snow coat should be carried out strictly according to the instructions. If the equipment is not equipped with special automatic devices to thaw a snow coat, then during thawing, remove all products from the cooled chamber, turn off the refrigeration machine and open the doors. Melt water is collected in trays and removed from the equipment. It is wiped dry and then the refrigeration machine is turned on. Remove snow from the refrigeration evaporator using mechanical means This is not possible, as you can damage the evaporator wall and break the tightness of the system.
If the refrigeration equipment is not loaded with food, it should be turned off. At the end of the working day, all products from the display cases should be transferred to chambers, cabinets or counters, and the refrigerating machines of the display cases should be turned off.
Operating personnel are not recommended to open refrigerated chambers unless necessary. This increases the temperature and humidity in the chamber. Lighting in refrigerated rooms should only be turned on when loading or unloading food.
The correct operation of refrigeration machines and equipment can be judged by their operating mode.
Normal operation of refrigeration equipment. The normal operating mode of refrigeration equipment is considered to be the optimal mode, which ensures the maintenance of the required temperature in the refrigeration chambers at minimal operating costs. The main operating costs are electricity and cooling water.
The following factors influence energy consumption.
1. Compliance with the rules of operation of refrigeration equipment. Correct loading and placement of products in chambers, cabinets, display cases and counters, reducing the time spent visiting chambers, opening doors and sliding walls, timely thawing of the snow coat from the evaporator of the refrigeration machine and other measures ensure the operation of the refrigeration machine with a minimum operating time ratio.
2. The difference between the condensation and boiling temperatures of the refrigerant. The smaller the difference, the lower the energy consumption.
Approximate values for liquid refrigerant boiling and condensation temperatures are:
a) condensation temperature tk in capacitors c air cooled is equal to t to =t air2 +(10÷12ºС), where t air2 is the temperature of the air leaving the condenser. Heating of the air in the condenser is 2-4°C;
b) in water-cooled condensers, closed type, condensation temperature tc =t m water +(8÷10ºС), where t m water - average temperature cooling water. Heating of water in the condenser is 4-6°C;
c) in finned freon evaporators, the boiling point of the refrigerant is 12-15°C lower than the temperature of the cooled chamber. IN refrigerated display cases and household cabinets, the temperature pressure on the evaporator can reach 19-21°C;
d) in direct cooling ammonia evaporators, the boiling point of the refrigerant is 8-12°C lower than the air temperature in the chambers;
e) in freon and ammonia evaporators for cooling the intermediate coolant, the boiling point of the refrigerant is 4-6°C below the average temperature of the coolant. The coolant in the evaporator is cooled by 2-4ºС;
f) the average temperature of the coolant in chamber batteries is 8-10°C lower than the air temperature in the chambers.
3. Incorrect relay setting low pressure automatic freon refrigeration machines when a small dead zone is set. In this case, short-cycle operation of the machine and a high cycle frequency are observed. The normal number of cycles is 5-6 per hour.
4. Overflow of the refrigeration machine evaporator with liquid refrigerant and the compressor running wet. The reason for this may be incorrect adjustment of the thermostatic valve, and the consequence is a decrease in compressor performance, an increase in pressure in the evaporator, an increase in the compressor operating time coefficient and increased energy consumption.
5. Compressor malfunctions, valve failures causing a decrease in performance, weakening and slipping of the belt drive, clogged dirt trap, etc.
Operating costs for cooling water in large refrigeration machines reach 50%, and in small refrigeration machines, where it is used only for cooling condensers, 25-35%. A decrease in the flow of cooling water to the condenser is associated with an increase in the condensation temperature. An increase in condensation temperature by 1ºC leads to a decrease in the cooling capacity of the machine by 1-1.2% and an increase in energy consumption. And with an increase in the supply of cooling water, electricity consumption decreases, but the consumption of cooling water increases. The optimal flow rate of cooling water should be determined taking into account operating conditions and tariffs for water and electricity. To save cooling water, you should pay attention to the operation of the water control valves, which should shut off the water supply to the condenser, subcooler and compressor when the machine is stopped.
Visual signs of normal operation of the refrigeration machine are: uniform distribution of a layer of frost over the surface of the evaporator, absence of frost on the suction pipe of the compressor (with the exception of low-temperature equipment, when the suction pipe to the suction valve of the compressor is covered with a layer of frost), warm liquid pipe, the compressor and electric motor operate quietly , without vibration and extraneous noise, there is no sparking and local heating in electrical appliances, the working time coefficient corresponds to the recommended values.
For various refrigeration equipment and machines, the operating instructions may recommend characteristic features normal operating mode.
The actual operating mode of the equipment is determined from the measured pressures and temperatures. It is considered abnormal if the actual cooling capacity is less and the energy consumption is more than optimal. In this case, it is necessary to reconfigure the equipment to operate normally.
Possible malfunctions in the operation of refrigeration equipment. During operation of refrigeration machines and equipment, their characteristics deteriorate. Due to wear, compressor performance decreases, noise and vibration appear that are absent in a new machine, etc. Contamination and corrosion of heat transfer surfaces cause an increase in their thermal resistance, reduction in strength properties.
Mechanical and physico-chemical wear cause problems in the operation of refrigeration equipment. Among the many violations, the most common are the following: malfunction of the starting and protective electrical equipment, continuous operation of the compressor of the automatic refrigeration machine, the required temperature in the refrigeration chamber is not achieved in the absence of a snow coat on the evaporator, there is a constant flow of cooling water to the condenser (the air cooler does not close) when the and a stopped compressor, extraneous noise in the compressor, etc.
Organization of repair of refrigeration equipment. To increase the service life of refrigeration equipment with high technical indicators it periodically undergoes scheduled preventive maintenance (PPR). The PPR system is designed to prevent emergency repairs and increase the time between repairs. It also includes work on overhaul maintenance, which consists of monitoring the condition of equipment and compliance with the rules of its operation, as well as performing a number of works that ensure long-term serviceable operation of machines and devices.
Planned repairs are divided into three types: current, medium and capital. Each type of repair includes operations that ensure trouble-free operation of the equipment until the next scheduled repair. Current and medium repairs are carried out without dismantling the equipment. Major renovation are produced at a repair and installation plant, for which the equipment is dismantled and sent to the plant.
By doing repair work it is necessary to strictly observe the safety rules for ammonia and freon refrigeration units, the rules for the technical operation of electrical installations and the requirements of other instructional materials.
The full cycle of operation of refrigeration equipment includes measures for delivery to the installation site, installation and commissioning, service and refrigeration equipment maintenance, warranty repairs and post-warranty service. To ensure trouble-free and long-term service of products, all of the above work has a certain significance.
But it’s worth focusing separately on maintenance, which in certain situations becomes vital. Regular maintenance, during which preventive actions, allows you to promptly identify problems and breakdowns of machines, troubleshoot problems in a timely manner and support high level performance of refrigeration systems. These actions will prevent complete failure of refrigeration equipment, thereby saving enterprises money on expensive repairs and costs associated with damage to goods.
Maintenance of refrigeration equipment is carried out at certain intervals and is scheduled, preventive and periodic in nature. The duration and volume of work included in the list depends on the purpose and type of units, technical condition, modes of use and operating time. Inspection of equipment cooling systems is carried out based on the requirements of operational documents for each individual type of devices and equipment.
The main purpose of maintenance of refrigeration equipment is periodic inspections, repairs and prompt elimination of failures and malfunctions refrigeration system and electrical equipment of machines.
Considering that refrigeration equipment is a complex electrical structure that is used in rather difficult conditions, you should trust the equipment’s service only to highly qualified specialists who will not only carry out the necessary measures efficiently, but also give competent advice on operation and preventing possible breakdowns.
Maintenance of refrigeration equipment can be one-time (or when putting machines into operation), seasonal and planned. One-time, including a certain list of operations (assessment of technical condition, cleaning and flushing of capacitors, identification possible malfunctions) is carried out before or after starting refrigeration machines, as well as after a certain operating time or based on the technical condition of the products.
Seasonal maintenance of refrigeration equipment is only necessary for those machines that are used under significant changes weather conditions during a year. The planned one is carried out with a certain regularity, in accordance with the requirements established by the manufacturers.
Planned maintenance is the optimal solution, since with this approach certain faults are identified and eliminated in advance. It is carried out at least once a month, if necessary 2-3 times monthly. The cost of servicing refrigeration equipment is calculated individually depending on the power of the machines, their technical condition, conditions of use and quantity installed products. The conclusion of a maintenance agreement occurs after the purchase of equipment.
The list of work carried out during the period of maintenance of refrigeration equipment includes:
In addition, the oil level in the compressor crankcase and refrigerant, condensation pressure, solenoid and water control valves must be monitored. Checked temperature regime in a refrigerated volume and automatic operating mode. A note is made in the accounting journal about the activities carried out.
In cases of identified malfunctions or, if necessary, during maintenance of refrigeration equipment, additional measures are taken:
Timely and competent maintenance of refrigeration equipment is the basis for its uninterrupted and long-term operation.
