Mechanical knowledge base: "compressor"

Compressor , a driven fluid machine that delivers gas and raises gas pressure. It is the heart of the refrigeration system. It sucks low-temperature and low-pressure refrigerant gas from the suction pipe, drives the piston through the motor and compresses it, and then discharges high-temperature and high-pressure refrigerant gas to the exhaust pipe to provide power for the refrigeration cycle. Compression → Condensation → Expansion → Evaporation (endothermic) refrigeration cycle.

Compressors generally consist of housings, motors, cylinders, pistons, control equipment (starters and thermal protectors), and cooling systems. Cooling methods include oil cooling and natural cooling.

Household compressors for household refrigerators and air conditioners use single-phase alternating current as the power source, and their structural principles are basically the same. Both use different refrigerants. Compressor production The compressor is produced in a streamlined manner. In the machining workshop (including casting), parts such as cylinders, pistons (rotary shafts), valve plates, connecting rods, crankshafts, end caps, etc. are manufactured; rotors and stators are assembled in the motor workshop; housings are manufactured in the press shop. Then assembly, welding, cleaning and drying are performed in the assembly shop, and the final package is delivered after inspection. Most compressor manufacturers do not produce starters and thermal protectors, but purchase them from the market as needed.

Compressor energy-saving method

When the compressor is started, the current of the motor will be 5-6 times higher than the rated value, which will not only affect the service life of the motor but also consume more power. The system will leave a certain margin in the design of the motor. The speed of the motor is fixed, but in actual use, it is sometimes necessary to operate at a lower or higher speed. Therefore, it is necessary to carry out frequency conversion. The inverter can realize the soft start of the motor, achieve the purpose of energy saving and speed adjustment by changing the frequency of the input voltage of the equipment, and can provide the equipment with protection functions such as over-current, over-voltage and overload. Domestic inverters are better manufacturers have three crystals, such as British Witten.

species

At present, household refrigerators and air-conditioner compressors are volumetric type, which can be divided into reciprocating and rotary type. Reciprocating compressors use pistons, cranks, linkage mechanisms, or pistons, cranks, and slide tubes. Rotary shaft crankshaft mechanisms are used.

According to the application range, it can be divided into low back pressure type, medium back pressure type and high back pressure type. Low back pressure (evaporation temperature -35 ~ -15 °C), generally used for household refrigerators, food freezer and so on. Medium back pressure (evaporation temperature -20 ~ 0 °C), generally used for cold drinks counters, milk coolers and so on. High back pressure (evaporation temperature -5 ~ 15 °C), generally used for room air conditioners, dehumidifiers, heat pumps, etc.