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How to do regular maintenance of rotary screw air compressor

April 23, 2021

How to do regular maintenance of rotary screw air compressor


Rotary screw air compressors have been comprehensively promoted and used in the industrial field. The superiority of screw rotary screw air compressors cannot be replaced by other machines. The superior performance of stability, high efficiency, energy saving, and low noise has been recognized by the majority of users.


A rotary screw air compressor suitable for use in your own factory is very important. In addition, rotary screw air compressors, like other equipment, have a life cycle.

Under normal circumstances, as long as they are used properly, minimum 10 years is not a big problem, but During the use of the 10 years, the rotary screw air compressor needs to have routine maintenance on time. It is extreme important to keep the machine running.


So what are the specific maintenance steps?

1. Replace the oil filter. The oil core should be replaced in time after the first 500 hours of operation of the new equipment, and the new filter element should be periodically replaced after 3000 hours of operation.

2. Maintenance and replacement of engine oil. The new equipment must be replaced with new oil after 500 hours of running-in period, and every 3000 hours of operation thereafter. It is best to change the oil filter together when changing the oil, there must be impurities inside.

3. Maintenance and replacement of the air filter element. The air filter element is best replaced every six months.

4. Maintenance and replacement of oil. The life cycle of the oil content is 3000 hours. If the oil content expires or the pressure difference before and after exceeds 0.12Mpa, it must be replaced.

5. Maintenance of the cooler. The rotary screw air compressor cooler is cleaned once a year, because the heat dissipation effect of the cooler directly affects the operating temperature of the screw rotary screw air compressor.


In addition to these routine maintenance, you also need to check and clean the following parts

1. Check the joint contact and insulation resistance of the electrical part of the rotary screw air compressor;

2. Replace the motor grease (replace every 8000 hours of operation). If there are parameters in the equipment manual, the manual shall prevail;

3. Clean the relief valve (intake valve);

4. Clean the minimum pressure valve (pressure maintenance valve);

5. Clean the oil return check valve;

6. Clean the temperature control valve;

7. Clean the cooler;

8. Clean the water separator;

9. Correct all parameters.

Note: The above maintenance should only be carried out after the equipment is confirmed that there is no electricity and no pressure.


2. Operation method:

1. Check the joint contact and insulation resistance of the electrical part of the rotary screw air compressor:

The electrical part of the rotary screw air compressor is divided into the main circuit, control circuit and signal transmission (temperature, pressure sensor) circuit. Due to the vibration generated during operation of the rotary screw air compressor, some wire joints will become loose after a long time. Loose wire joints may cause the unit to fail to start, and at worst, cause serious disasters such as protection function failure, arc short circuit, electric shock and so on. Therefore, the electrical part should be checked regularly.

When checking, you can swing the wires one by one by hand, feel the tightness of the thread ends, and tighten the loose thread ends;

In addition, it is necessary to use a shaker to test the insulation between the motor, equipment and the ground. The insulation resistance should be controlled above 500 megohms, otherwise it should be dried or repaired.


2. Replace the motor grease:

The front and rear ends of the motor are installed, and the service life can be guaranteed under proper lubrication. Therefore, grease should be injected regularly. The type of grease should be selected according to the parameters provided by each manufacturer.


3. Rotary screw air compressor cleaning relief valve (also called intake valve):

(1) Unloading valve composition: Unloading valve is composed of valve body, spool (piston), gas circuit manifold, solenoid valve and proportional valve (accommodating valve).

(2) Load relief valve function: The load relief valve mainly controls the loading (screw rotary screw air compressor heavy vehicle), unloading (empty vehicle), proportional (capacity adjustment) control function of the rotary screw air compressor, and can also prevent lubrication when the rotary screw air compressor is stopped Oil sprayed from the main engine

(3) Disassembly of the relief valve: 1 remove the hose connecting the relief valve and the air filter; 2 remove all other parts and the air pipe connected to the relief valve; 3 remove the solenoid valve coil; 4 remove the relief valve and assemble the host And remove the nut; 5 move the relief valve to the ground covered with clean paper or related clean paving.

(4) Cleaning the relief valve: (rotary screw air compressor cleaning agent should be soapy water, diesel oil, clean gasoline, natural water, etc., the above cleaning agents should be selected according to the degree of dirt, generally recommended to use soapy water or diesel for cleaning)


Dismantle the solenoid valve: dismantle the solenoid valve and check whether the O-rings and seals in the solenoid valve need to be replaced (reminder: if you are not familiar with the intake valve, please also write down the position of the removed component to avoid errors when reinstalling), If there is no need to replace, put the disassembled screws, O-rings, seals, electromagnetic rods, cores and other components into a pre-prepared container and soak them in appropriate cleaning agents (Note: Use gasoline and thinner water for cleaning Please do not soak rubber products such as O-rings for too long to avoid corrosion);

Dismantle the proportional valve: remove the proportional valve from the valve body, then unscrew the adjusting nut (it is better to mark the nut before screwing to avoid too large deviation of the proportional value when reinstalling), take out the valve core, O-ring, U-shaped ring, spring and check whether O, U-shaped ring needs to be replaced (all the sealing rings and springs removed by screw rotary screw air compressor must be checked, and I will not repeat it in the following description), remove it The components are soaked in the cleaning agent.


Dismantle the manifold block of the air circuit: remove the manifold block from the valve body, and there are air holes on the four sides of the manifold block (the hole of the screw rotary screw air compressor is used to clear the air circuit when the integrated air circuit is blocked). Unscrew the sealing nut and put the integrated block together in the cleaning agent to soak.


Dismantle the valve core of the relief valve: use a circlip pliers to remove the circlip at the connection between the spool and the valve body, and then use a pipe wrench to unscrew the spool, and take out the cylinder, valve disc, O-ring, U-ring, and The spring is soaked in the cleaning agent, and then the air inlet on the valve body is removed, and the entire valve body is soaked. At this time, the disassembly process of the relief valve has been completed.


Cleaning: If the dirt on the intake valve is serious, change a new cleaning agent when cleaning. During the cleaning process, wash the cleaner parts first and then wash the dirty parts. The cleaned parts should be rinsed again with clean water to avoid Corrosion shortens the service life of parts. Parts washed with clean water should be placed in a clean place to dry in order to prevent iron-containing parts from rusting.

When cleaning the valve plate and the place where the valve body and the valve plate are in contact, pay attention to the smoothness of the surface, and clean it, and replace it if necessary, otherwise it will cause the rotary screw air compressor to start with load (the large screw rotary screw air compressor unit starts with load. Can not start phenomenon will occur).


Install components: install the components according to the reverse steps of disassembly. It should be pointed out that when installing the components, the position of the sealing ring and the movable components should be coated with an appropriate amount of engine oil, so that the sealing ring can be installed better and the movable parts can be better. flexible.

Note: Since there are many parts in the relief valve, if you are not sure about the position of each part, you can remove each part and then install the part after cleaning, but do not install the part on the valve body first, wait until all parts are cleaned Assemble to the valve body together.

After the entire cleaning process of the relief valve is completed, put it aside to be loaded into the rotary screw air compressor.


4. Clean the minimum pressure valve (the rotary screw air compressor is also called the pressure maintenance valve):

(1) The minimum pressure valve composition: the minimum pressure valve is composed of a valve body, a spool, an adjusting nut, a spring, and a sealing element.

(2) The function of the minimum pressure valve: the minimum pressure valve is mainly used to establish the internal pressure of the unit, promote the circulation of lubricating oil, and meet the working pressure of the relief valve. In addition, the minimum pressure valve also functions as a check valve to prevent the unit from unloading. The compressed air in the air storage tank flows back to the rotary screw air compressor during operation.

(3) Disassembly of the minimum pressure valve: The structure of the minimum pressure valve is very simple. Unscrew the nut of the rotary screw air compressor between the valve core and the valve body to take out the components inside. The minimum pressure valve spool of the small unit is built into the valve. Body, all the internal components can be taken out by disassembling the valve body cover.

(4) Clean the minimum pressure valve: Clean the minimum pressure valve according to the method of cleaning the relief valve.

(5) Assembly of the minimum pressure valve: assemble the components according to the reverse steps of disassembly. Since the structure of the minimum pressure valve is very simple, the assembly process will not be described one by one, but note that if there is a U-shaped ring inside, pay attention to U The direction of the ring.

(6) After the entire cleaning process of the minimum pressure valve of the rotary screw air compressor is completed, put it aside to be installed in the rotary screw air compressor.


5. Clean the oil return check valve

(1) The composition of the one-way valve: the one-way valve is composed of valve body, steel ball, steel ball seat, spring and other elements.

(2) The role of the oil return check valve: the oil and air mixture compressed by the main engine is first separated by centrifugal force in the oil and air tank. Because the weight of the oil is greater than air, most of the oil in the solid oil and air mixture falls to the oil by centrifugal force. The tank and rotary screw air compressor return to the main engine for a lubrication cycle under the action of internal pressure, and the compressed air containing a small amount of oil is separated again by the oil-air separator. At this time, the lubricating oil separated by the oil-air separator will fall off. To the bottom of the oil and air separator, in order to prevent this part of oil from being carried away with the compressed air, the unit is designed with an oil pipe inserted into the bottom of the oil and air separator, and this part of the oil is directly introduced to the main engine for lubrication through internal pressure. There is a one-way valve on the oil pipe, and the rotary screw air compressor is called the oil return single valve.

Its function is to smoothly recover the oil from the oil and air separator to the main engine without allowing the oil from the main engine to flow back to the oil and air separator.

(3) Disassembly of the oil return single valve: there is a connection point in the valve body, unscrew it from this point, and take out the spring, steel ball, and steel ball seat.

(4) Cleaning the oil return check valve: clean the valve body, spring, steel ball, steel ball seat with cleaning agent, and some check valves have a filter inside. If there is any, clean it together.

(5) Assembly of the oil return check valve: install the check valve according to the reverse steps of disassembly.

(6) After the entire cleaning process of the one-way valve is completed, put it aside to be loaded into the rotary screw air compressor.


6. Rotary screw air compressor cleaning temperature control valve

(1) The composition of the temperature control valve: the temperature control valve is composed of a valve body, a valve core, a temperature sensing element, a spring, etc.

(2) The function of the temperature control valve: the temperature control valve plays the role of constant temperature control. When the oil temperature measured by the temperature sensing element of the temperature control valve is lower than the action value (the action value of the temperature sensing element is generally 71 degrees), the lubricating oil is directly Return from the oil and air barrel to the main engine. When the oil temperature measured by the temperature sensing element of the temperature control valve is higher than the action value, the thimble of the temperature sensing element of the temperature control valve will act and push the valve core to open the bypass valve of its own equipment, so that the lubricating oil enters into cooling. The device is cooled (the higher the temperature measured by the temperature sensing element, the greater the opening of the bypass valve), and the cooled lubricating oil returns to the main engine.

(3) Disassembly of the temperature control valve: the rotary screw air compressor has a cover on the surface of the temperature control valve, and there are screw holes on the cover, find a suitable nut to screw in the cover, and then use the circlip pliers to remove the fixed cover The circlip, and then use the pliers to pull the nut just screwed in, then the cover and all the internal parts can be taken off.

(4) Cleaning the temperature control valve: clean all parts of the temperature control valve according to the method of cleaning the relief valve.

(5) Assembling of temperature control valve: install the temperature control valve according to the reverse steps of disassembly.

(6) After the entire cleaning process of the temperature control valve of the screw rotary screw air compressor is completed, put it aside to be installed in the rotary screw air compressor.


7. Cleaning the cooler:

(1) The cooler is divided into two types: air-cooled and water-cooled. 7.2 Cleaning of the cooler:

Air-cooled cooler

Open the air baffle to clean the cover, or remove the cooling fan.

Use compressed air to blow the dirt down, and then take the dirt out of the air deflector; if it is dirty, spray some

Blow the degreaser again. When the screw rotary screw air compressor cannot be cleaned by the above methods, the cooler needs to be removed, soaked or sprayed with cleaning fluid, and cleaned with the help of brushes (wire brushes are strictly prohibited).

Install the cover or cooling fan

Water-cooled cooler

Disassemble the cooling water inlet and outlet pipes.

Inject cleaning solution to soak or use pump to circulate flushing (recoil effect is better).

Rinse with clean water.

Install the cooling water inlet and outlet pipes.

When the scale of the oil cooler is serious and the cleaning by the above method is not ideal, you can remove the oil cooler separately, open the two end covers, and use a special cleaning steel brush or other tools to remove the scale. When cleaning the medium side of the cooler cannot effectively reduce the temperature, the screw rotary screw air compressor needs to clean the oil side. The method is as follows:

Disassemble the inlet and outlet tubing.

Inject cleaning solution to soak or use pump to circulate flushing (recoil effect is better).

Rinse with clean water.

Blow dry with dry air or use dehydrated oil to remove water.

Install the inlet and outlet tubing


8. Clean the water separator

The structure of the water separator of a screw rotary screw air compressor is similar to an oil and air tank. The air inlet is designed against the wall, and the solid shape is centrifugal force. Due to the weight of water and vapor, it can effectively separate the water in the compressed air.

Cleaning of the water-air separator: remove the cover of the water separator, and then use the detergent to infuse and clean.


9. Correct all parameters

After all the above parts are cleaned and dried, they should be installed in the rotary screw air compressor. After all parts are installed in the rotary screw air compressor, check again for omissions and clean up the tools and other items used during installation.

The operating parameters of the rotary screw air compressor can be adjusted according to the following data: () Preparation before starting the screw rotary screw air compressor:

() Belt (coupling) correction: If the rotary screw air compressor is driven by a belt, the belt tightness should be between 10 and 20 mm. If the rotary screw air compressor is driven by a coupling, it should be turned by hand after installation Motor and host and check the balance of the coupling when it rotates. The couplings of screw rotary screw air compressors basically adopt elastic couplings, which can be ignored when the deviation of solid balance is not large.

(1) Screw rotary screw air compressor main engine steering correction: If the main power supply has been removed during the maintenance process, pay attention to the forward and reverse rotation of the motor after the power supply is connected. The rotation of the motor should be based on the steering of the main engine. The turn icon on the host.

Correction method: Exchange any two power lines in the three-phase power supply.

(2) Loading, unloading, and proportional value validity: when setting these three parameters, the unloading value should be determined first, and the unloading value should be determined according to the combination of the rated pressure of the rotary screw air compressor and the required pressure at the air end to determine the unloading value Then, set the loading value. The pressure difference between the two should be between 0.1~0.2Mpa. After setting the unloading and loading values, finally set the proportional value. The proportional value should be set between the unloading value and the loading value. The screw is empty. Compressor example: If a factory needs the rotary screw air compressor supply pressure of 0.8Mpa, and the air supply requirement is relatively stable, three parameters should be set as follows: unloading pressure setting 0.8Mpa, loading pressure setting 0.65Mpa, proportional control The pressure is set between 0.73~0.75Mpa.

Screw rotary screw air compressor calibration method: set this parameter in the microcomputer controller (if the rotary screw air compressor is controlled by buttons, the loading and unloading parameters should be adjusted from the pressure switch, and the proportional value should be in the proportional valve on the unloading valve. Adjust the value at the adjusting nut).

(3) The internal pressure effect of the unit is positive: the internal pressure of the unit should be between 0.2~0.45Mpa.

Correction method: The pressure value should be carried out when the unit is unloaded, and the value should be adjusted on the adjustment nut of the minimum pressure valve. In order to facilitate the reading of the adjusted value, the pressure detection point should be taken before the minimum pressure valve and the pressure should be installed. Gauge (some microcomputer controllers have internal pressure parameter display function, if there is no such function, a pressure gauge should be installed before the minimum pressure valve).

(4) The high temperature protection value is positive: When the screw rotary screw air compressor is working normally, its temperature should be between 65 and 98 ℃. The automatic shutdown temperature of over-temperature protection shall not exceed 105°C.

Correction method:

Adjust the high temperature automatic shutdown temperature value in the controller. Take 1.2 (that is, enlarge the margin by 20%);


Conclusion

Regardless of whether the rotary screw air compressor is routine maintenance or the user's daily maintenance, it is equally important. Don't lose out because of a little maintenance cost. Then your rotary screw air compressor can run smoothly and stably to contribute into your business growth constantly.


Product Keywords: rotary screw air compressor, regular maintenance of air compressor, routine maintenance of air compressor, oil filters, air filters, oil separator core.

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