portable screw air compressor LGCY Operating instructions second page

Chapter 2, Construction and Operating Principles

1, Architecture and system flow

1.1, Machine construction (omitted)

1.2, System flow: main air system, control air system, oil system

1.2.1, Main airway system

The main air circuit system consists of air filter, air inlet valve, screw mainframe, oil-air separator (including oil separator core), minimum pressure valve and so on.
Outside air through the air filter to filter out dust, impurities, through the air inlet valve into the screw host suction chamber, and in the compression process and the injection of lubricating oil mixing. After compression, the oil-air mixture is discharged into the primary oil-air separator (oil-air barrel), more than 99% of the oil is separated off, and then after further separation by the secondary oil-air separator (oil separator core), the clean compressed air passes through the minimum pressure valve and enters into the use system.
A. Air filter
The air filter is a dry paper filter with a pore size of about 10um. Its main function is to filter the dust in the air.
B. Air intake valve
The air inlet valve is of disc type, through the opening, half-opening and closing degree of the disc, it can realize the adjustment of the air inlet (i.e. exhaust volume) to achieve the purpose of energy saving.
C. Screw host
With the rotation of the rotor, the size of the tooth groove space formed by the negative and positive rotors changes, completing the inhalation, compression and discharge of air. At the same time in the compression, lubricating oil is also sprayed into the compression chamber due to pressure difference and mixed with air, and discharged to the oil and gas separator together.
D. Oil-air separator
In order to reduce the oil content in the exhaust (i.e. reduce oil consumption) and recycle the lubricating oil in the unit, it is necessary to utilize the oil-air separator. From the host of the oil and gas mixture into the primary oil and gas separator (oil and gas barrel), the use of mechanical collision method, the separation of the vast majority of the lubricating oil; and then, the oil content has been greatly reduced oil and gas mixture at a lower rate of flow into the secondary oil and gas separator (oil sub-core), the use of affinity agglomeration method, and further separation of residual lubricants.
E. Minimum pressure valve
The cleaner compressed air after separation is fed into the system through the minimum pressure valve. The opening pressure of the minimum pressure valve is set at about 0.45Mpa, which mainly has the following functions:
(1). Priority is given to the establishment of circulating pressure required for lubricating oil when starting to ensure the lubrication of the machine.
(2). When the gas pressure of the oil and air tank exceeds 0.45Mpa, the valve will be opened only after the oil and air tank is opened, which can reduce the air flow speed through the oil separator core, in addition to ensuring the separation effect of the oil separator core, and protect the oil separator core from being damaged due to the large pressure difference.
(3). Check function: When the pressure in the oil and gas barrel drops after stopping the machine, it can prevent the compressed air in the pipeline from flowing back.

1.2.2, Control airway systems

The control air system consists of load and unload switching valve (solenoid valve), proportional valve, bleeder valve, air inlet valve servo cylinder and safety valve.
A. Load and unload switching valve (solenoid valve)
Loading and unloading switching valve is a solenoid valve controlled by a manual switch for loading/unloading switching. Load reduction at startup and before shutdown, loading during working hours, the machine relies on the proportional valve to fully automatically regulate the operation.
B. Proportional Valve
Proportional valve is the regulator, is the key component of the pressure control, it converts the working pressure (input pressure) into control pressure (output pressure), the output pressure of the output pressure determines the expansion and contraction of the two servo cylinders.
C. Inlet valve servo cylinder
Servo cylinder is the actuator. The intake valve servo cylinder controls the opening of the intake valve disc according to the level of the proportional valve output pressure, thus controlling the intake volume.
D. Bleeder valve
Bleeder valve is installed in the minimum pressure valve after the use of the system pipeline, it is also subject to the control of the proportional valve output pressure, the appropriate time to the atmosphere to discharge, reduce the excessive system pressure.
E. Bleeder valve
The air release valve is installed after the oil separator core and before the minimum pressure valve, it is also controlled by the output pressure of the proportional valve, and it will be released to the atmosphere at the right time to gradually reduce the pressure in the oil and gas tank.
F. Safety valve
Safety valve is to ensure the safe operation of the machine parts, under normal operating conditions do not act. If the safety valve continuous action, you should promptly check the reasons (such as air inlet regulation failure, diesel engine throttle regulation failure, etc.), and promptly exclude. For large displacement compressor, if the system gas consumption is suddenly reduced to zero, the pressure may rise faster than the reaction speed of the pneumatic adjustment, so that the safety valve opens to relieve pressure.
The safety valve has been adjusted at the factory.
The method of checking the safety valve is to gently pull the air release lever on the safety valve when the compressor is working at full capacity, if the safety valve can discharge air to the outside at this time, it will be regarded as normal.

1.2.3, Oil system

The oil circuit system without oil pump, the lubricating oil relies on the pressure difference between the compressor's discharge port and the host's oil injection port to maintain the flow in the circuit. When the machine is running, the lubricating oil in the oil and gas barrel under the action of differential pressure, through the temperature control valve into the oil cooler, cooled and then through the oil filter to remove impurities particles, most of the lubricating oil is sprayed into the compressor compression chamber, and the rest of the lubricating oil were passed to the bearings, shaft seals, etc., to play a role in lubrication, sealing, cooling, noise reduction, and so on. Finally, all the lubricating oil with the compressed gas is discharged into the oil and gas barrel, separating out the vast majority of the lubricating oil for recycling. The small amount of lubricating oil separated from the oil separator core is also led back to the suction port of the compressor and other low-pressure places.
A. Oil cooler
The oil cooler cools the circulating lubricating oil. The fins of the oil cooler are easily covered by dust, which affects the cooling effect and may lead to high exhaust temperature and shutdown, so it should be blown and cleaned every once in a while to ensure its cooling effect.
B. Oil Filter
The oil filter is a paper filter whose function is to remove impurities in the oil, such as metal particles, oil deterioration, etc., to protect the bearings and the normal operation of the rotor. Its filtration precision is between 10μ~15μ. The oil filter is a disposable consumable, if the oil filter is clogged and not replaced in time, it may lead to insufficient oil intake, increased head exhaust temperature, resulting in shutdown; at the same time, insufficient oil will also affect the service life of the host bearing.
C. Oil and gas drum
Oil and gas bucket is also called primary oil and gas separator, which utilizes mechanical collision method to separate oil from oil and gas mixture. The side of the barrel is equipped with an oil level indicator. The oil and gas barrel is equipped with a sewage ball valve below to exclude the oil and gas barrel condensate (because the water is heavier than the oil, precipitation in the lower part). There is a refueling hole on the barrel for refueling.
D. Oil Separation Core
Oil separating core is also called secondary oil and gas separator, using affinity aggregation method to further separate out the residual lubricating oil. Oil separator core is made of multi-layer fine glass fiber, compressed air contained in the mist of oil through the oil separator core can be almost completely filtered out, oil particle size can be controlled in the following 0.1um, the oil content can be less than 5PPm. by the oil separator core separation of a small amount of lubricating oil, concentrated in the groove at the bottom of the oil separator core, through the oil check valve is led back to the compressor suction port, such as low-pressure place. Under normal operation, the oil separator core can be used for about 500-1000 working hours, but the lubricant oil and the degree of pollution of the surrounding environment has a great impact on its life. If the environmental pollution is very serious, consider installing a pre-filter. As for the choice of lubricating oil, must be recommended by the company's screw compressor oil. Avoid mixing different grades of lubricating oil and using fake oil.
Generally speaking, whether the oil separator core is damaged can be judged by the following methods:
A. Check the pressure difference before and after the oil separator core with the switching valve, whether it exceeds 0.1Mpa;
B. Whether the oil content in the air pipeline increases.
C. Temperature control valve
The machine is equipped with a temperature control valve in front of the oil cooler, whose function is to maintain the head exhaust temperature above the pressure dew point temperature to avoid condensation of water vapor in the air in the oil and gas barrel and emulsification of lubricating oil. When the machine is just turned on, the lubricating oil temperature is bottom, at this time, the branch circuit of the temperature control valve is open, the main circuit is closed, and the oil does not go through the oil cooler but directly into the body. If the oil temperature rises to 83 ℃ or more, the temperature control valve gradually open to the oil cooler path, usually to 94 ℃ when the full open, at this time the oil will be all cooled by the oil cooler and then enter the body.

2, Principle of operation of oil-injected screw compressors

2.1, Suction process:

Screw compressor air intake is regulated only by the opening and closing of an intake throttle valve. When the yin and yang rotor teeth groove space to the housing inlet wall opening, its space is the largest, at this time the rotor below the teeth groove space and the inlet of the free air through, because in the exhaust air in the teeth groove of the air was discharged in full, exhaust finished, the teeth groove is in a vacuum state, when the turn to the air inlet, the outside world air that is sucked in, and along the axial flow into the teeth groove of the yin and yang rotor. When the air fills up the whole tooth groove, the air inlet side of the rotor is turned away from the air inlet of the casing, and the air between the tooth grooves is closed, the above is the "air inlet process".

2.2, Closure and conveying process:

At the end of the suction, the peaks of the teeth of the yin and yang rotor and the casing seal, the air in the tooth groove no longer outflow, this is the "closed process". The two rotors continue to rotate, the tooth peak and tooth groove in the suction end of the anastomosis, the anastomosis surface gradually to the exhaust end of the move, this is the "conveyor process".

2.3, Compression and injection process:

In the conveying process, the meshing surface gradually move to the exhaust end, that is, the space of the tooth groove between the meshing surface and the exhaust port is gradually reduced, and the air in the tooth groove is gradually compressed, and the pressure gradually rises, which is called the "compression process". At the same time of compression, the lubricant is also sprayed into the compression chamber and mixed with the air due to the pressure difference.
Oil injection has four main roles:
A, lubrication: lubricant can form an oil film between the rotors, avoiding the contact between the rotors, reducing friction;
B, cooling effect: as the lubricant absorbs a large amount of compression heat, so that the compression process is close to isothermal compression, reducing the specific power of the compressor;
C, sealing effect: the oil film produced by the lubricant can play a sealing effect on the compressed air, improve the volumetric efficiency of the compressor;
D, noise reduction: reduce the noise generated by high-frequency compression.

2.4, Exhaust process:

When the rotor exhaust port end face and the casing is connected (at this time the highest pressure of the compressed gas), the compressed gas began to discharge, until the tooth peaks and grooves of the meshing surface to the casing of the exhaust end of the end face, at this time the two rotor meshing surface and the casing of the exhaust port of the groove between the space of zero, which is the completion of the "exhaust process". At the same time, the length of the groove between the meshing surface of the rotors and the air inlet of the casing reaches the longest length, thus starting a new compression cycle.

3, Model KS3003 National III Screw Air Compression Control System

3.1, Product Overview

KS3003 diesel air compressor controller (hereinafter referred to as controller) is a fully automatic National III diesel portable screw air compressor monitoring system designed by 32-bit high-performance ARM chip, combined with advanced control technology and CAN communication technology. It can accurately detect the diesel level, air supply pressure and exhaust temperature, and through CAN communication, it can control the engine speed in real time, read the real-time engine speed, oil pressure, water temperature, battery voltage, engine air inlet pressure, air inlet temperature, instantaneous fuel consumption, engine failure and other information, which are shown on the display. According to the data set by the user, it monitors the parameters of the air compressor, sends out the corresponding control signals, and can alarm and prompt to the user through sound and light signals.
Easy to install and use.
(1), Strong anti-interference capability.
(2), Multi-level password protection.
(3), Resistant to vibration, high and low temperatures, humidity, salt spray and other harsh environments, IP65 rating of control panel.
(4), CPU adopts 32-bit high performance ARM chip, high reliability.
(5), Real-time detection of air supply pressure, exhaust temperature, oil level and other information.
(6), Has 2 CAN communication interfaces, CAN1 supports J1939 protocol and ECU direct communication; CAN2 is used as a slave to communicate with external devices.
(7), Built-in a variety of engine ECU communication data. It is convenient for customers to select diesel engine.
(8), Real-time reading of the engine's operating data, fault warning data, and stored in the controller.
(9), 7 inch color screen display, resolution of 800 * 480, key operation, adapt to a variety of complex working conditions.
(10), integrated PID control, according to the detection pressure real-time adjustment of engine speed, to achieve constant pressure gas supply.
(11), With 485 communication module, it can be used as a slave to communicate with external equipment according to Modbus protocol and modify parameters remotely.
(12), Pressure and temperature can be calibrated in real time, and the pressure range can be set up to 4.0MPa (see calibration parameters).
(13), Temperature sensor type can be selected from Cu50 and Pt100 for easy replacement.
(14), Can display engine fault information in real time and store in history fault information.

3.2, Main technical indicators

3.2.1, Working environment
(1), Operating environment temperature: -30℃ to +70℃; relative humidity: ≤98%; vibration resistance>4g.
(2), vibration: 2 to 25Hz, amplitude 1.6mm; 25 to 100Hz, acceleration ±40m/S2.
3.2.2, Pressure measurement
(1), Measuring range: Exhaust pressure 0.00 to 4.00MPa.
(2), Measurement accuracy: 0.5 level.
(3), Sensor: HUBA high-temperature 4-20mA pressure sensor.
3.2.3, Exhaust gas temperature measurement
(1), Measuring range: -40℃ to +150℃.
(2), Measurement accuracy: 0.5 level.
(3), Sensor: Cu50 copper resistance sensor or PT100 platinum resistance.
3.2.4, Diesel level measurement
(1), Measuring range: (0 to 100)%.
(2), Measuring accuracy: 1%.
(3), Sensor: 0 to 130Ω corresponds to (0 to 100)%. It can also be calibrated to other resistance values.
3.2.5, CAN communication interface
Controller with two CAN communication, both CAN2.0B, baud rate 250Kb/s, CAN1 support J1939 protocol and can control the engine speed.
3.2.6, Display mode
7 inch LCD color screen display, analog tachometer, barometer and other dynamic graphics.
3.2.7, System power supply
DC24V.

3.3, Controller shape

(1), Emergency stop: when an unexpected situation occurs, press down and then stop immediately;
(2), stop: when pressed, the speed is reduced to idling speed, then stop the machine;
(3), start: when pressed, start the machine and automatically disconnect the start relay when the speed exceeds the start speed;
(4), Load/Decrease: select the working state.

Chapter 3, Main Performance and Technical Parameters

For technical specifications, please visit the links below:
portable screw air compressor LGCY