Air compressor (air cooled)

Structure and working principle

The compressor is double stage, single acting, piston type. F for air cooling, s for water cooling.

The compressor adopts crankshaft connecting rod mechanism. The crankshaft is installed on the rolling bearings at both ends of the crankcase, and the belt pulley is installed at the left end of the shaft. Class I cylinder and class II cylinder are installed on the crankcase with flange positioning. The big end of the connecting rod is Haff type and fixed with connecting rod screws. The connecting rod is connected with the piston through the piston pin. A certain number of gas rings are installed on the pistons at all levels for sealing. At the same time, oil rings and oil scraping rings are installed to lubricate and collect the excess lubricating oil on the cylinder wall and return it to the crankcase. The air valves at all levels are ring valve, tongue spring valve or combination valve which can open and close automatically with the change of pressure. The safety valve and control valve are spring regulated.

The motor or diesel engine drives the crankshaft to rotate through the belt pulley, the crank pin of the crankshaft drives the big end of the connecting rod to rotate, and the small end of the connecting rod drives the piston to reciprocate in the cylinder through the piston pin. Class I compressed air is cooled by interstage cooler, and then compressed to rated pressure by class II before entering the cylinder.

The gas cylinder unit is composed of mobile gas cylinder, compressor, B-type V-belt and motor or diesel engine. The compressed air enters the cylinder through the check valve. The pressure of the gas in the cylinder is indicated by the pressure gauge. When the compressed air exceeds the set pressure, the control valve, safety valve or pressure control device work successively.

Automatic control and safety device

1. Electric control device:

The electric control device can automatically stop the compressor when it is overloaded, unload and start when it is lower than the set pressure.

The electric control device is composed of pressure controller, solenoid valve, one-way valve and electric control box.

Open the switch of the electric control box, the solenoid valve is closed, the compressor inflates the gas cylinder, and the pressure controller adjusts to the upper and lower limits of the required pressure within the rated pressure range. When the pressure in the cylinder reaches the upper limit, the electric signal sent by the pressure controller is transmitted to the electric control box, the compressor stops running, the solenoid valve is powered on, and the compressor is unloaded. Since the check valve is installed at the inlet of the cylinder, the pressure in the cylinder will not drop. When the pressure in the bottle is lower than the lower limit, the pressure controller will send an electrical signal to the electric control box, and the compressor will restart.

2. Safety protection device:

In order to make the compressor work safely, class I and class II Safety valves are equipped. The class I safety valve has the function of manual unloading at the same time. The opening pressure of the safety valve has been adjusted during assembly and lead seal has been added. The opening pressure of safety valve: class I is 0.6-0.8mpa, class II is 3.1-3.3mpa.

The water-cooled air compressor is equipped with a safety film on the I-stage cooler. When the cooling water pressure exceeds the specified value, the safety film will explode automatically.

When the compressor is equipped with electric control device, the electric control box is equipped with overload shutdown protection device. When the overload is caused by the abnormal state of the compressor, which causes the input current of the motor to exceed the setting current of the thermal relay in the control circuit, the thermal relay will automatically disconnect, cut off the power supply, and force the motor and the compressor to stop.