Commercial refrigeration equipment knowledge

 Compressor failures are mainly manifested as "not starting", or called "cylinder stuck", "shaft stuck", etc. Compressor turn-to-turn is a fatal failure, which can only be dealt with based on changing the compressor. The main manifestation of the compressor turn-to-turn condition is that the compressor cannot be started, so that the motor is damaged, or the overload protector often does not work when it starts. For DC inverter compressors, the main performance is that the speed ratio cannot be increased, and the soft starter is over-voltage protection.
　　 1. The compressor motor is destroyed
　　The wiring of the compressor terminal block is wrong and the motor is damaged; the system software refrigerant leaks; because the high pressure gas of the rotary compressor is discharged from the compressor, it is also responsible for the motor to generate heat. If the system refrigerant leaks, there will always be a small amount of high-pressure gas discharged to the compressor, so that the heat generated by the compressor motor will always accumulate when the compressor is plugged in, which will cause damage to the compressor motor in the long run .
　　2. Compressor capacitor problem
　　 The power capacitor is destroyed (short-circuit failure, short-circuit); the specifications and models of the power capacitor do not match the compressor.

The main reason for the deterioration of the oil in the compressor
　　1. Mixing oil and water
　　 The refrigeration oil is mixed with water. If moisture enters the refrigeration system due to improper operation, after mixing with the refrigerating machine oil, it will reduce the viscosity of the refrigerating machine oil and reduce the oil's lubricating performance.
　　2, high temperature oxidation
　　Refrigeration oil is oxidized at high temperature. When the exhaust temperature of the compressor is high, not only the viscosity of the oil will decrease and its lubrication performance will be affected, but also the oxidation and deterioration of the oil may be caused. Especially for refrigerating machine oil with poor thermal stability, free carbon is decomposed around the exhaust valve plate in a high temperature environment, which causes the valve plate to be not closed tightly and reduces the air delivery coefficient of the compressor.

What is the exhaust temperature of the shrinking machine? The exhaust temperature of the shrinking machine originally refers to the high-pressure superheated vapor of the refrigerant after the shrinking operation. According to the working principle of the shrinking machine, given that the refrigerant secreted by the shrinking machine is overheated Steam, so we might as well conclude that there is absolutely no correspondence between the pressure and temperature of the shrink machine.
     It should be noted that the exhaust temperature of the shrink machine can be read by relying on the thermometer on the exhaust pipe.
     In addition, the exhaust pressure is usually slightly higher than the condensing pressure, and the exhaust temperature is much higher than the condensation temperature. In addition to the refrigerant type, the exhaust temperature is also related to the suction temperature, pressure, and pressure. With the necessary contact,
     At the same time, it also increases with the increase of the suction temperature, pressure and pressure ratio. Therefore, during the operation of the machine, if the condensation temperature and exhaust temperature are too high, it will cause the shrinking machine to operate. There is a necessary crisis, at this time, it is reasonable to stop continuing the operation of the machine.

When the chiller has a high-voltage alarm, let's deal with related matters from the following aspects. Let's take a look at the overall handling method.
     First, we need to check the condition of the cooling water to ensure that its water pump can be turned on. If it is normal, then it should not be the cause of the water pump.We must continue to eliminate the faults in other departments.
     Second, we need to check whether its dry filter can be blocked fiercely. If the blockage is serious, we must clean its condenser. This is also a relatively important task, and we must control its cooling water. The system, to ensure that its capillary is free, must be necessary in order to avoid being blocked.
     Third, let's take a look at the situation on its pressure gauge. From this aspect, to deal with the problem of high-pressure alarm, the electromagnetic chuck business feels that from this aspect, we might as well compare it and judge that there is really a high-pressure problem. .

The main function of the liquid receiver installed in the refrigeration system of the screw chiller is to store the refrigerant and adjust the cycle volume of the refrigerant, and adjust the liquid consumption of the refrigerant according to the change of the heat load of the evaporator. According to the difference of function and working pressure, the liquid container is divided into four types: high pressure reservoir, low pressure reservoir, low pressure cycle cylinder and drain cylinder.
    The liquid reservoir is made of steel coils, and there are various joints and accessories attached to the upstream to combine the pipeline and control. The liquid reservoir commonly used in screw chillers is usually located after the condenser, and its usefulness The first is:
    1. Reserve the refrigerant liquid flowing out of the condenser, so that the heat transfer area of the condenser can be fully utilized;
    2. Guarantee to provide and mobilize the amount of refrigerant liquid circulation required by the relevant settings in the screw chiller refrigeration system;
    3. It serves as a liquid seal, that is, to prevent high-pressure refrigerant vapor from escaping into the low-pressure system pipeline;

Rose tea is a health-preserving beauty, and it is a favorite of many beauty lovers. Chinese medicine believes that rose buds have the effects of relieving depression, relieving stasis, regulating menstruation and relieving pain, and softening cardiovascular and cerebrovascular; its sweet and slightly bitter taste, warm nature, can nourish people's heart, liver and blood vessels, relieve qi stagnation in the body, play and comfort Antidepressant effect. Generally, rose buds should be harvested before they open, that is, the best harvest is when the longitudinal diameter of the flower bud is 3 times the calyx. The yield will be reduced too early, and the flowers will open too late and affect the quality. Choose strong and full buds during the concentrated flowering period, and pick the petals of other delicate buds when they are fully opened. Flowers that bloom sporadically at other times will also pick their petals after they are fully opened. The rose drying equipment can also collect rose cell sap while drying the roses. Today we give a brief introduction to the air energy rose dryer.
The air-energy rose heat pump dryer adopts low temperature, enhanced circulating air, and strong dehumidification for drying, which can ensure the natural color and full shape of the rose, without damaging the flower shape, or destroying its natural medicinal effect, and the nutrients will not be lost. The heat pump The dryer has a high degree of automation and does not require special supervision. The drying process is all controlled by a microcomputer.

1. Pre-treatment of roses before drying　　
Some people in the industry perform color protection treatment before drying the roses. The specific implementation method is to change the PH value in the cell fluid of the flower material, or to kill at high temperature to increase the stability of the pigment, and to kill or passivate the material. Enzyme activity to carry out color protection treatment.

What are the differences between the heat pump low temperature evaporator and the steam method? The difference between the heat pump low-temperature evaporator and the steam method is mainly the difference between the working principle and the working method. The editor of Kang Jinghui will give you a brief introduction on the difference between heat pump low temperature evaporator and steam evaporation.
　　The low-temperature heat pump evaporator is a heat pump evaporator that depends on what heat source is used. According to the type of driving energy, the low-temperature heat pump evaporator is divided into two categories: motor drive and heat drive.

Thermally driven heat pump low-temperature evaporators can be divided into thermal energy driven (such as absorption heat pump, steam jet heat pump) and other types.
　　 heat pump low temperature evaporator is divided into vapor compression heat pump according to the principle, this kind of heat pump is a relatively common form. It is usually circulated in a system composed of compressors, condensers, throttling devices, evaporators and other components, and the purpose of pumping low-grade heat energy to high-grade temperature areas is achieved through state changes and phase changes of the working fluid.

Principle of refrigerator compressor
　　 At present, household refrigerators and air conditioner compressors are both positive displacement, which can be divided into reciprocating and rotary. The rotary type uses a shaft crank mechanism. According to the scope of application, it can be divided into low back pressure, medium back pressure, and high back pressure. Low back pressure type (evaporating temperature -35～-15℃), generally used in household refrigerators, food freezers, etc. Medium back pressure type (evaporation temperature -20～0℃), generally used in cold drink cabinets, milk refrigerators, etc. High back pressure type (evaporating temperature -5～15℃), generally used in room air conditioners, dehumidifiers, heat pumps, etc. Reciprocating compressors use piston, crank, connecting rod mechanism or piston, crank, slide tube mechanism.

1. Composition of refrigerator compressor
Refrigerator air conditioners are composed of four major parts: compressor, condenser, expansion valve and evaporator. According to control or use needs, you can choose to install auxiliary devices such as pressure controller, temperature controller, and filter dryer, but the four major parts There must be a lot.

Refrigerants are also called refrigeration working fluids, commonly known as refrigerants in some areas in the south. It is a working substance that continuously circulates in the refrigeration system and realizes refrigeration through its own state changes. The refrigerant absorbs the heat of the cooling medium (water or air, etc.) in the evaporator to vaporize, and transfers the heat to the surrounding air or water in the condenser to condense. Recently, the refrigerant industry has suddenly heated up. HCFC-22 (R22) increased by 18% and 12% in March and April, respectively. The share prices of listed refrigerant companies reached their daily limit in mid-May, producing R22, etc. The product enterprises started to achieve full load. Some refrigerant companies are optimistic that, driven by them, some refrigerant products will reproduce the strong recovery momentum in 2011. On the other hand, third-generation refrigerant products such as HFC-134a are under the dual pressure of domestic overcapacity and foreign "double reverse" investigations, and corporate profits have fallen sharply. In view of the current status of refrigerants, how should the industry achieve sustainable development? Today, China Refrigeration Network takes everyone into the world of refrigerants.

Refrigerant classification and use
　　 According to the ingredients, there are the following.
　　1, single refrigerant
　　2, mixed refrigerant. (Note: A single refrigerant contains only one chemical substance, and its thermal and physical performance parameters are constant. For example, R134a, R152a and other refrigerants have high energy efficiency. Mixed refrigerants are composed of two or more A mixture of agents.)　　

Heat exchanger is a kind of equipment that transfers part of the heat of hot fluid to cold fluid, also known as heat exchanger. Heat exchanger plays an important role in chemical, petroleum, power, food and many other industrial production. It can be widely used as heater, cooler, condenser, evaporator and reboiler in chemical production.

development
Heat exchanger is a kind of energy-saving equipment to realize heat transfer between two or more fluids with different temperatures. It is to transfer heat from the fluid with higher temperature to the fluid with lower temperature, so that the fluid temperature can reach the index specified in the process, so as to meet the needs of process conditions. At the same time, it is also one of the main equipment to improve energy utilization. The heat exchanger industry involves more than 30 industries, such as HVAC, pressure vessel, reclaimed water treatment equipment, chemical industry, petroleum and so on, forming an industrial chain with each other. Data show that the market scale of heat exchanger industry in 2010 is about 50 billion yuan, mainly concentrated in petroleum, chemical industry, metallurgy, electric power, shipping, central heating, refrigeration and air conditioning, machinery, food, pharmaceutical and other fields. Among them, petrochemical industry is still the largest market of heat exchanger industry, with a market scale of 15 billion yuan; the market scale of heat exchanger in power metallurgy is about 8 billion yuan; the market scale of heat exchanger in shipbuilding industry is more than 4 billion yuan; the market scale of heat exchanger in machinery industry is about 4 billion yuan; the market scale of heat exchanger in central heating industry is more than 3 billion yuan, and that of food industry is nearly 3 billion yuan The market. In addition, aerospace vehicles, semiconductor devices, nuclear power conventional island, nuclear island, wind turbine, solar photovoltaic power generation, polysilicon production and other fields all need a large number of professional heat exchangers. These markets have a scale of about 13 billion yuan. The heat exchanger industry has made remarkable achievements in energy saving and efficiency improvement, heat transfer efficiency improvement, heat transfer area reduction, pressure drop reduction, and heat intensity improvement. Based on the steady growth of heat exchanger demand in petroleum, chemical, electric power, metallurgy, shipbuilding, machinery, food, pharmaceutical and other industries.

classification

A separator is a machine that separates mixed substances into two or more different substances. The common separators are centrifugal separator and electrostatic separator.
Equipment introduction
In order to keep good separation effect, the liquid level and pressure of the separator should be controlled. Constant pressure control technology is used to control the liquid level and pressure of traditional separator. In the variable pressure liquid level control of the separator, the float liquid level controller is used to drive the oil and gas regulating valve to make it work together to control the liquid volume of crude oil and natural gas, so as to adjust the liquid level of the separator without controlling the pressure of the separator. The liquid level control method of variable pressure can reduce the throttle of the oil and gas outlet valve to the greatest extent, reduce the pressure of the separator, and improve the separation effect.
Oil gas separator and oil gas water three-phase separator are widely used in oil field transfer station and combined station. In order to keep good separation effect, the liquid level and pressure of separator need to be controlled.
working principle

The piston refrigeration compressor is the heart of the refrigeration system. It sucks in the refrigerant gas with low temperature and low pressure from the suction port, and drives the piston to compress it through the motor operation. After that, it discharges the refrigerant gas with high temperature and high pressure to the exhaust port, providing power for the refrigeration cycle, so as to realize the refrigeration cycle of compression → condensation → expansion → evaporation (heat absorption).
Compressor is generally composed of shell, motor, cylinder, piston, control equipment (starter and thermal protector) and cooling system.
When the piston is in the lowest position (called the inner dead center or bottom dead center), the cylinder is filled with low-pressure refrigerant vapor from the evaporator, and the suction process ends; the piston starts to move upward driven by the crankshaft connecting rod mechanism, at this time, the suction valve closes, the working volume of the cylinder gradually decreases, the gas in the cylinder is compressed, and the temperature and pressure gradually increase When the pressure of the gas in the exhaust chamber rises slightly higher than the pressure of the gas in the exhaust chamber, the exhaust valve opens and begins to exhaust. The process of gas rising from the low pressure of suction to the exhaust pressure in the cylinder is called compression process.