July 11, 2023 Plastic Drum blow molding machine

Different air compressor configurations, different air compressor prices


Most customers only know how big air compressor they need to buy, but how to buy, why to buy in this way, what kind to buy and so on are not very clear. Sometimes, it is not that customers are willing to simply pursue the low price, but when he is not clear about the details of the air pressure system, he had to choose the low price of the product.


Below, we have the same specification air compressor price differences in the reasons and performance to do a simple analysis for your reference.

1, different brands of host efficiency differences

The national mandatory energy-efficiency standard “Energy Efficiency Limit Value and Energy Efficiency Rating of Volumetric Air Compressor” (GB 19153-2019), which will be implemented on July 1, 2020, is receiving the attention of many screw machine assembly plants and distributors. The energy efficiency grade of screw air compressor mainly depends on three major factors: the efficiency of screw host/motor and the resistance of the whole system. Among them, the screw host efficiency index – specific power is the determining factor of energy saving.


Theory and practice have proved that: the efficiency of the screw host depends on its rotor profile, as well as rotor machining accuracy, rotor engagement gap, exhaust end gap these factors in the manufacturing process caused by the error superimposed on the screw host operation of the “internal leakage”.


Although with the rapid development of the air compressor industry, technology continues to mature, there are many brands of hosts on the market, but due to the design of the profile, processing accuracy and other factors, the efficiency of different brands of air compressor hosts is still relatively obvious differences. Even if some air compressors are smaller in size, they may still lead in efficiency! Therefore, basically the same specifications than the product, the price difference of a few thousand dollars also has a certain degree of reasonableness.


We take 22kW, 7.5kg/cm2 model as an example for comparison:

A hosts B hosts C hosts
drive (vehicle) leather belt leather belt Belt or direct connection
Pressure 7.5kg/cm 7.5kg/cm’ 7.5kg/cm
Exhaust volume 3.5m³/min 3.5m³/min 3.5m³/min
Shaft power 22.0kw 23.8kw 22.0kw
Rotation speed 4260r/min 5173r/min 2950r/min
How much power does the life cycle consume? 1.8kW*50000/hour*1元/度=9万元 About the same as A
How long does it take to make up the $10,000 difference in the price of the whole machine? 10000元:1元/度:.8kW=5555 hours(a year About the same as A

2, no temperature control valve cat

The role of the air compressor temperature control valve is to control the head exhaust temperature, its working principle is that the temperature control valve core according to the principle of thermal expansion and contraction, through the outstretching, contraction to regulate the valve body and the shell between the formation of the oil channel, so as to control the proportion of the lubricating oil into the oil cooler, as a way to ensure that the rotor temperature is in the set interval. This is because when the head exhaust temperature is too low, moisture will precipitate out in the oil and gas barrel, causing the lubricant to emulsify. The temperature control valve forces the lubricant to enter the head directly without passing through the oil cooler when the machine is started up cold. When the oil temperature rises to a certain value, the temperature control valve completely opens the channel of the oil cooler, at this time the lubricating oil is cooled by the oil cooler and then sprayed into the head.


If the user can ensure that their air compressor will run at full load most of the time, then the air compressor will not accumulate water inside, and the temperature control valve really does not play a big role. If you can’t be sure, then you must make sure that there is a temperature control valve inside the air compressor, otherwise it is easy for the main engine to seize.


If there is no temperature control valve, winter and spring are accident-prone times. Getting an air compressor with a temperature control valve will at least give you peace of mind, although it will cost you nearly a thousand dollars more.


3, whether the electronic control system is reliable

The electric control system of the screw air compressor is generally composed of emergency stop button, transformer, sensor, contactor, transformer, fuse, terminal block, welding material solenoid valve, wire (the old electric box consists of: push button switch, thermal relay, time relay, intermediate relay, indicator light) and other parts.


We need to determine whether the sensor is stable, the solenoid valve is reliable, and the PLC is reassuring. If the air compressor is equipped with a well-known brand sensors, the cost increase of 200 to 400 yuan is certain, assured that the choice of electrical appliances will also increase the purchase cost of 300 to 400 yuan to ensure stability of the solenoid valve, the cost increase of 200 to 300 yuan is also certain, the benefit is to be sure that it is reliable performance.

4、Air compressor with as little as possible hose

Inside the air compressor, because of the high pressure gas, high temperature, and contains a lot of lubricating oil, the life of the hose is not long (except for the section of piping behind the oil points, because there is no oil there), and the cost will rise.



5, radiator performance to meet the demand

The same specifications, materials and models of the radiator, the difference from the appearance is difficult to compare, but the thickness of the plate will directly affect the service life of the radiator. Some manufacturers in order to cut corners, the actual thickness of the plate than its claimed thin, which will cause the weight of different brands of radiators are different.


For example, 21kg weight of all-aluminum radiators, enough to use the full load in hot areas need to use the cooling area, and can be reserved 30%, to prevent the use of a number of years later, the thermal performance of the decline can also be used. However, some companies’ heat sinks may only be 16kg, without reserving a rich amount, and it is no problem to use it in the first year, but after the warranty period, it often jumps out of the machine at high temperature, which makes the use of such a machine very painful. Therefore, set aside 30% of the product can reduce the worries, alone, pay a few hundred dollars more is worth it.

6, whether the motor has a reservation factor

The advantage of giving the air compressor’s motor reservation factor is: when the differential pressure of the oil fraction is relatively large, close to the time of replacement, the motor needs to increase close to 10% of the electricity cost. In addition, in the actual production application, we can not 100% guarantee that the grid voltage will not be lower than 380V, then when the voltage decreases, the current is bound to increase, there is no reservation factor of the motor will jump. If the setting of protecting the motor is enlarged, it is easy to burn the motor. Therefore, it is necessary to invest an additional 200 to 300 dollars to increase the motor service factor by 10 to 15%.



7、Bearing needs of the motor

Bearings are very critical parts of the motor, bearing system selection and maintenance of good and bad, directly affect the life of the motor and operational reliability. Choose an excellent brand, the cost will also increase 200 to 300 yuan.

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