Detailed instructions for loading and unloading of air compressors?

Loading and unloading the air compressor is a means to adjust the pressure of the air compressor, and it is also the root of the air compressor operation, so everyone must know about this piece!

In general, the loading and unloading control is such that the pressure of the compressed gas varies between PMIN pmax. PMIN is the lowest pressure that can ensure the normal operation of the user, also known as the minimum pressure value. The conversion relationship between pmax and pmin is as follows:

pmax (1 δ) pmin (1), where the parameter δ is a percentage between 10% and 25%. When we use frequency conversion speed regulation technology to continuously adjust the gas supply, then the pressure of the pipe network will always be maintained around the minimum pressure value pmin.

Through this information, we can know that compared with the air compressor under the control of the frequency conversion system, the air compressor under the control of the gas supply mode of adding and unloading will mainly produce energy waste in two parts:

1) In the process of compressing air in the air compressor, the pressure of the compressed air exceeds the minimum pressure value, that is, the energy consumed by pmin, after the pressure of the compressed air reaches pmin, the pressure will continue to rise to pmax due to the original control mode. Then this process will release a lot of energy to the outside world, resulting in a large loss of energy.

When the gas higher than the pmin enters the pneumatic element, the pressure will be reduced by the pressure reducing valve after the pressure is reduced, and the pressure will drop to a position close to the pmin. This process also consumes energy.

2) During the unloading process, the energy is consumed due to the incorrect way of pressure regulation.

Generally speaking, when the pressure reaches the highest pressure value pmax, the air compressor mainly depressurizes and unloads by the following method: close the intake valve to keep the motor in a dry state, and at the same time empty the excess compressed air in the separation tank. This method results in a large amount of compressed air being wasted, resulting in a large waste of energy.

Although closing the intake valve to make the motor idle can make the air compressor no longer need to do work, the air compressor is still driving the screw to rotate in the idling state, so that the energy consumption of the air compressor when unloading accounts for about 15% 20% of the air compressor when it is running at full load. In short, the air compressor is in a no-load state 15% of the time, and it is doing useless work. Therefore, we know that when the air compressor is controlled by the loading and unloading air supply, the air compressor motor has a huge potential for energy saving.

2.Problems with intake and bleed valves.

1) When the inlet valve is mechanically adjusted, the air supply cannot be continuously adjusted, and when the air consumption is constantly changing, the air supply pressure will continue to fluctuate significantly. In addition, the accuracy of gas consumption does not meet the process requirements. Then frequent adjustment of the intake valve will accelerate the wear of the intake valve, which will affect the quality of the compressed air of the air compressor and increase the maintenance volume and maintenance cost.

2) Frequent opening and closing of the air release valve will lead to a decrease in the durability of the air release valve, which will eventually affect the normal operation of the air compressor and bring losses to production.

The screw air compressor unit is composed of the screw compressor host, motor, oil-air separator, cooler, fan, water separator, electrical control box, air pipeline, oil pipeline, regulating system, etc. There is a pair of yin and yang rotors that are precision machined to mesh each other in the main body of the compressor. For direct connection units, the motor directly drives the male rotor through the elastic coupling, and for the gear drive unit, the motor drives the gear shaft through the elastic coupling, which in turn drives the male rotor through the gear drive.

The injected oil is mixed with air and effectively compressed between the rotor coggings, forming an oil film between the rotor coggings, avoiding direct metal-to-metal contact and sealing the gaps between the rotor parts and absorbing most of the compression heat. The unit does not have an oil pump, and the oil pressure is sent to each lubrication point by the gas pressure in the oil-air separator. The oil and gas mixture discharged from the compressor passes through the oil-gas separator, and most of the oil is coarsely separated by cyclone separation, and the remaining oil is further refined separated through the oil separator filter element and settles at the bottom of the filter element.

The oil at the bottom of the filter element is introduced into the compressor by the return pipe using the pressure difference, and the oil level gauge, minimum pressure valve and safety valve are installed on the oil vapor separator. The oil-air separator also doubles as a fuel tank and a gas storage tank.

The loading and unloading of the air compressor is actually equivalent to the circulating working mode of opening the intake valve to make gas and closing the intake valve to stop the air production. Its working principle: according to the pressure required for our work, the air pressure of the air compressor is set a maximum pressure and the minimum air pressure, when the pressure of the compressor reaches the maximum limit of the set when the gas is temporarily used or reduced in the work, the compressor closes the intake valve, and the machine enters the no-load load operation state.

When the air is restored or the air pressure drops to the set minimum air pressure, the compressor opens the intake valve and the machine enters the load loading state. This set of control processes is the process of unloading and loading. The accessories that control the compressor are generally electric valves, pressure regulating valves, pneumatic valves and other supporting accessories.

We can use these valves to adjust the upper and lower pressure limits of the compressor to achieve the working purpose, which is conducive to the advantages of automatic, energy-saving, safe and prolonging the service life of the machinery.

If the air pressure is enough, it will be unloaded, and if it is not unloaded, the pressure will be too high and unsafe, and it will also cause unnecessary energy consumption. So uninstalling, uninstalling the program for a long time will be down.

Unloading is not gas-producing, but it also wastes electricity, and the inverter transformation is to achieve a constant voltage output. Minimize the energy consumption caused by unloading time.

Air compressor inverter course thirteen talks about air compressor installation and unloading.

The air compressor must have an unloading process because when the main pressure reaches 8 bar, the internal pressure of the machine will be greater than 8 bar.

If the air compressor continues to load and run when the rated pressure is exceeded during operation, the maximum pressure value will be reached, causing the screw air compressor to trip and stop, or the safety valve will operate. Stop directly, and the intake valve will close without urgency, resulting in fuel injection from the air filter. There needs to be an unloading process to reduce the pressure in the body of the machine and stop it only after the intake valve is closed.

The solution to the air compressor that cannot be unloaded:

1. Overhaul the pressure switch and replace it if necessary.

2. Replace the maintenance kit of the inlet valve and add lubricating oil.

3. Overhaul or replace the unloading solenoid valve.

4. Overhaul or replacement.

5. Check whether the loading solenoid valve is faulty, and replace the loading solenoid valve if necessary.

When the air compressor is in the running state, the pressure sensor on the air supply outlet pipe of the unit reaches the preset minimum working pressure value, and the air compressor begins to load (that is, the process of compressing air begins), and the preset minimum working pressure is the loading pressure of the air compressor.

In the same way, when the loading process of the air compressor is about to be completed, the pressure transmitter reaches the preset maximum working pressure, which triggers the unloading of the air compressor (that is, the intake valve is closed to stop the compressed air from bending), and the preset maximum working pressure is the unloading pressure of the air compressor.

Before starting, the oil pump control system is started first, and the oil pump control system ensures that the lubrication parts of the air compressor are well lubricated, and the oil pump control system can adjust the internal oil pressure and oil temperature through the built-in temperature control valve to meet the needs of the system.

When the motor is running at a constant frequency, the panel shows the pressure fluctuating up and down. Workaround: Replace it with another onePressure sensors

The value of the air supply pressure and the unloading pressure is too close: when the air compressor reaches the air supply pressure, if the air consumption suddenly decreases, the inverter will not have time to control the motor to slow down, which will cause excessive gas production, resulting in unloading. Workaround:

Set the difference between the supply pressure and the unloading pressure larger, usually the difference.

Precautions for the use of air compressors.

Air compressor disguised.

During operation, pay attention to the meter reading (especially the reading of the barometer) at any time, listen to the sound of each department, and stop the machine immediately for inspection if any abnormal situation is found. The maximum air pressure in the gas tank shall not exceed the nameplate.

Stipulate the pressure of the imperial demolition. Every 2 4h of work, the condensate oil and water discharge valve of the intercooler and the gas storage tank should be opened 1 2 times. Do a good job of cleaning the machine, after the air compressor has been running for a long time, it is forbidden to wash it with cold water.

When the air compressor is shut down, the exhaust valve of the gas storage tank should be gradually opened, the pressure should be lowered slowly, and the speed of the diesel engine should be reduced accordingly, so that the air compressor can run for 5 10 seconds at no load and low speed. After the air compressor stops, the diesel engine continues to run for 5 seconds at low speed and then stops. In winter, when the temperature is lower than 5 degrees, the unmixed antifreeze should be drained after the shutdown.

of cooling water.