Work flow of air compressor

Workflow

1. Air flow: free air & rarr;& rarr;& rarr; air filter & rarr;& rarr; relief valve & rarr;& rarr; primary air intake valve & rarr;& rarr; primary air exhaust valve & rarr;& rarr; secondary air intake valve & rarrr; & rarrr; secondary exhaust valve & rarr;& rarr;(aftercooler) & rarr;& rarr; air bag & rarr;& rarr; working point.

2. Power transmission process: motor & rarr;& rarr; V-belt pulley & rarr;& rarr; crankshaft & rarr;& rarr; connecting rod & rarr;& rarr; crosshead & rarr;& rarr; piston rod & rarr;& rarr; piston.

Classification

according to the working mode of compressed gas: piston type, centrifugal rotary three basic types.

According to the working principle, it can be divided into positive displacement compressor and speed compressor. The working principle of positive displacement compressor is to compress the volume of gas, so that the density of gas molecules per unit volume is increased to increase the pressure of compressed air; the working principle of speed compressor is to increase the movement speed of gas molecules, so that the kinetic energy of gas molecules is converted into the pressure energy of gas, thereby increasing the pressure of compressed air.

According to the size of the exhaust volume classification: 1. micro air compressor: exhaust volume in the following one cubic meter per minute. 2. Small air compressor: the displacement is between 1~10m 3 /min. 3. Medium-sized air compressor: the displacement is between 10~100m 3 /min. 4. Large air compressor: the displacement is more than 100m 3 /min.

According to the level of exhaust pressure classification 1. Low pressure air compressor: pressure in 3~10kg force/cm?. 2. medium pressure air compressor: pressure in 10~100 kgf/cm?. 3. high pressure air compressor: pressure in 100~1000 kgf/cm 4. ultra high pressure air compressor: pressure is greater than 1000 kgf/cm?

Composition

taking the most common L-type air compressor in the coal industry as an example, the composition of the air compressor is introduced.

1. Structural features: two-stage, double-cylinder, double-acting, water-cooled, fixed air compressor.

2. Structure division: divided into six parts (institutions)

(1). Compression mechanism: It is composed of cylinder, suction valve, exhaust valve piston and other components.

(2). Transmission mechanism: It is composed of V-belt pulley, crankshaft, connecting rod crosshead and bearing.

(3). Lubrication mechanism: composed of gear oil pump, oil injector and oil filter.

(4). Cooling mechanism: It is composed of intercooler, cooling water jacket of cylinder, cooling water pipe, aftercooler lubricating oil cooler and other devices.

(5). Regulating mechanism: composed of relief valve, pressure regulator, etc.

(6). Safety protection device: It is composed of safety valve, oil pressure breaker, water cut-off switch and pressure relief valve.

The main components of the. L-type air compressor 1. Fuselage: made of gray cast iron, it is the framework for supporting and assembling the components.

The shape is right-angled L-shaped, with detachable crosshead slideways at the vertical and horizontal necks, and flanges at both ends are used to connect with the 1. secondary cylinder assembly. The bottom of the fuselage doubles as an oil sump.

2. Crankshaft: Receives the power input by the motor in the form of torque, and converts it into the reciprocating force of the piston to compress air to do work.

The material is ductile iron, and there is a crank on which two connecting rods are arranged in parallel. The two ends of the main journal are equipped with double row radial spherical roller bearings.

The overhanging end of the shaft is keyed to the pulley.

The other end is equipped with a small shaft of the transmission gear oil pump and drives the oil injector through the worm gear mechanism. The two arms of the crankshaft are each bolted with a balance iron to balance the inertial force generated by the unbalanced mass during rotation and reciprocating motion.

A central oil hole is drilled on the crankshaft so that the lubricating oil discharged from the oil pump can lead to each lubricating part.

3. Connecting rod: A part that transmits the thrust acting on the piston to the crankshaft and converts the rotational motion of the crankshaft into the reciprocating motion of the piston.

It is composed of rod body, big head, small head, etc. The rod body is conical, with oil holes running through the size head. The big end of the connecting rod is divided into two halves, and the big head tile with babbit alloy lining is filled in. There are two groups of copper pads between them, which can adjust the radial clearance between the big head tile and the crank. The two halves of the big head tile are connected by two connecting bolts and installed on the crank.

The small end of the connecting rod is equipped with a phosphor bronze bearing bush to reduce friction. The connecting rod small head tile is inserted into the crosshead pin and connected to the crosshead, which can be removed from the circular window on the side of the fuselage.

4. Crosshead: It is a moving part that connects the piston rod and the connecting rod. It reciprocates on the crosshead slide and has a guiding effect. The material is gray cast iron. One end of the crosshead is connected with the piston rod with a thread, and the clearance of the cylinder can be adjusted by the screwing depth of the thread and the piston rod. After the crosshead pin is connected with the small head tile, it penetrates into the tapered hole of the crosshead body and is fixed on the crosshead with a key.

5. Piston assembly: including piston. Piston rings and piston rods.

(1). Piston: It is the main component of the compression mechanism. The rotational movement of the crankshaft, via the connecting rod. A crosshead. The piston rod becomes the reciprocating motion of the piston in the cylinder. This compresses the air to do work. Common piston shapes are cylindrical and disc. Air compressors with crossheads are all disc-shaped pistons. In order to reduce the quality, they are often cast into hollow, and the two end faces are connected with reinforcing ribs to increase rigidity. Material gray cast iron.

(2). Piston ring: also known as the expansion ring, it is a vulnerable part of the air compressor. Installed in the piston ring groove on the outer circle of the piston. An open ring with a square section made of gray cast iron has a certain elasticity. In the free state, the outer diameter is greater than the inner diameter of the cylinder. There are three types of cuts for the piston ring: straight cut. A diagonal cut. Overcut. The function of the piston ring: Use its own tension to make the outer surface of the ring close to the mirror surface of the cylinder, and the end surface of the ring close to the wall surface of the piston ring groove to prevent gas leakage. In order to avoid the leakage of compressed air from the incision, the two piston ring incisions should be staggered with each other, and the staggered angle should not be less than 120 °. In addition to the sealing effect, the piston ring also plays the role of oil distribution and heat conduction.

(3). Piston rod: Material 45 steel forged. The friction part of the shaft has been surface-hardened and has good wear resistance. One end of the piston rod is made into a conical body, inserted into the conical hole of the piston, and fastened with a crown nut with a cotter pin to prevent loosening. The other end of the piston rod and the crosshead are connected with threads, and the clearance volume is adjusted and tightened by the nut.

6. Cylinder: It is the main part of the compression volume of the piston air compressor. It is divided into inner and outer layers. The space between the two layers is a cooling water jacket for circulating cooling water. There are 4 valve chambers on the cylinder head and the cylinder seat. Install two suction valves and two exhaust valves respectively. The water jackets and gas paths of the cylinder head, cylinder block, and cylinder seat are correspondingly connected, but the water jackets and gas paths are separated from each other. There is a stuffing box inside the cylinder seat.

7. Valve: It is automatically opened and closed with the change of gas pressure in the cylinder. The air valve has a suction valve and an exhaust valve. They only allow air to pass in one direction. Whether it works normally or not directly affects the exhaust volume and power consumption. There are certain requirements for it:

(1). Long life.

(2). Small resistance, reduce power consumption.

(3). Good sealing, reduce the amount of air leakage.

(4). The clearance volume formed is small.

(5). The structure is simple, easy to manufacture and easy to repair.

(6). Low noise, timely action.

8. Packing device: when the air compressor is working, the relative movement between the piston rod and the cylinder seat is required. Therefore, there must be a certain gap. In order to prevent compressed air from leaking out of this gap, a packing device is provided to seal it. It also prevents lubricating oil from being carried into the cylinder by the piston rod. The L-type air compressor is sealed with metal packing. It consists of sealing ring, oil retaining ring, spacer ring and gasket. The sealing ring is made of gray cast iron and consists of 3 beveled petals. A tension spring is placed in its outer edge groove, and it is tightly clamped on the piston rod to play a sealing role. When the inner ring is worn, with the help of the force of the spring, it can automatically tighten inward to ensure the seal. The sealing ring is close to the cylinder. There is a ring groove on the inner surface of the oil retaining ring, which can scrape off the oil brought on the piston rod to avoid being brought into the cylinder. It is installed on the side close to the fuselage. There is a ring groove on the inner surface of the oil retaining ring, which can scrape off the oil brought by the piston rod to avoid being brought into the cylinder. It is installed on the side close to the fuselage.

Operation steps

1 Preparation

① Send thermal work ticket

② Three parties confirm safety measures

③ Stop the air compressor, close the air outlet, open the drain valve, and confirm that the system has no pressure;

2 Compressor Removal

1 Remove the air filter, intake valve, oil fine separator, heat control valve, oil filter, oil cooler, safety valve, pressure maintenance valve, relief valve, temperature switch, etc. from the chassis, and then remove the host And the motor.

2 Remove the belt, loosen the angle bolt, separate the main engine from the motor, pull out the pulley with a puller, disassemble and check the main engine, remove the gland at both ends of the main engine, take out the shaft seal assembly, remove the bearing gland, and knock out the bearing with a copper rod, Remove the driving screw, driven screw and other parts.

3 Cleaning and inspection of compressor

① Cleaning and inspection of all parts: Clean the removed parts with diesel oil, clean the bearings with gasoline, and remove dirt and rust debris with a shovel; clean or replace the air filter, oil filter, etc.

② Check each part one by one, and replace the parts that do not meet the requirements; the valves are flexible and well sealed.

③ Screw wear shall not exceed the original thickness of 1/3, replace the oil seal, bearing

4 Compressor assembly

1 Assemble the parts of the compressor in turn according to the principle of disassembly before assembly.

2 Assembly of the compressor host: install the driving screw and the driven screw into the compressor host, tighten it with bolts, knock the bearing into the bearing seat, install the shaft seal assembly, install the gland, and tighten it with bolts. Install the pulley in the chassis and motor assembly connection.

3 Connect the air filter, intake valve, oil fine separator, heat control valve, oil filter, oil cooler, safety valve, pressure maintenance valve, relief valve, temperature switch, etc. to the pipeline of the compressor host.

5. Test operation of the compressor The test operation of the compressor has no abnormal noise, and the loading and unloading are normal.