The situation of the chassis compression gas drying equipment presets

The compressed air in the regenerative air reservoir is blown back to the desiccant through the passage C, and the moisture adsorbed on the surface of the desiccant is taken away, and reaches the chamber A through the annular passage B and the filter screen, because the drain valve is opened and has moisture Compressed air is discharged into the atmosphere through the drain. When the air pressure in the pipeline drops, the feedback gas pressure is insufficient to overcome the preload of the pressure regulating valve spring, the pressure regulating valve is closed, the feedback gas acting on the drain valve piston is discharged, the drain valve is closed, and the air compressor is re-closed. Air is supplied to the air reservoir and the entire drying process is restarted.

The structure of the independent air dryer independent air dryer is that the upper part is equipped with a blowing chamber to regenerate the air reservoir, but there is no pressure regulating valve itself, so there is no automatic drying function, and an external pressure regulating device is required. The valve works with it to achieve the drying function, and the working principle is similar to that of the integral air dryer, and the description will not be repeated here. structure type.

Unreasonable design By analyzing the structure and working principle of the above two dryers, it can be recognized that the feedback gas in the dryer should be directly from the air reservoir, so that the dryer can correctly sense the air pressure in the air reservoir during operation. . However, the dryer piping of some chassis is designed to arrange the piping structure as in (a), (b).

The unreasonable form in the unreasonable structure is that due to the existence of the check valve of the gas cylinder, the feedback gas in the dryer line is only sealed in the trachea between the outlet of the dryer and the check valve of the gas cylinder. Less gas. From the analysis of the working principle of the dryer, it is known that the diaphragm and the valve of the dryer and the pressure regulating valve will open when the dryer is in operation, and the pipeline will be connected, so that the volume of the feedback gas will become larger and the corresponding pressure will decrease. According to the law of gas equation, Boyle's law, when the temperature of a certain mass of gas remains constant, the product of its volume and pressure is a constant, that is, P0V0=P1V1 where: P0 is the feedback gas when the gas is connected with the air reservoir, the dryer The pressure of the feedback gas before work; V0 is the volume of the feedback gas before the feedback of the feedback gas and the gas cylinder; P1 is the pressure of the feedback gas when the feedback gas is connected with the gas storage cylinder; V1 is the feedback gas and When the air reservoir is connected, the volume of the gas is fed back when the dryer is working. Where V1=V0+V other (the volume increased when each valve and pipeline is inflated) and thus P1=P0V0V1=P0V0V0+V, when the feedback gas is sealed in the air pipe between the dryer outlet and the gas cylinder check valve, The volume of the trachea is assumed to be calculated as 1/400 of the volume of the air reservoir, that is, P2V2=P0V0/400. In the formula: P2 is the pressure of the feedback gas when the feedback gas is sealed in the air pipe, and V2 is the feedback gas sealed in the air pipe. In the middle, the volume of the gas is fed back when the dryer is working. Among them V2=V0/400+V others.

Can get P2 = P0V0V0 + 400V other obvious, P2 In addition, more importantly, even if there is a slight outgassing in the joints and internal valves of the dryer and the pressure regulating valve, the check valve prevents the gas in the gas cylinder from being replenished, and is sealed in the dryer outlet and the single A small amount of feedback gas in the air pipe between the valves will quickly drop. Therefore, the regulator of the dryer cannot be maintained in the open state, and the air compressor quickly starts pumping, but does not inflate the air reservoir, but Inflate the 5L regenerative air reservoir or 1L of the purge chamber and the air tube before the check valve. When the feedback air pressure reaches 82,020 kPa, the dryer starts working again, and this process will be repeated frequently. This will inevitably reduce the service life of the desiccant. After the desiccant fails, the air brake system will accumulate water; the frequent work of the air compressor will increase the working load of the air compressor, resulting in an increase in the frequency of the air compressor failure, and It will increase the temperature of the outlet and adversely affect the operation of the dryer. In addition, the frequent operation of the air compressor will also increase the fuel consumption of the engine.

Improvement measures and effects Through the analysis of the working principle of the dryer, in view of the above unreasonable arrangement of the pipeline of the dryer, the one-way valve on the air reservoir can be improved into a four-circuit protection valve or a straight-through joint during design. It can directly feedback the air pressure of the air reservoir.

In the system before the improvement, the air pressure of the air reservoir did not decrease significantly while the air compressor was working frequently. The working interval of the air compressor was only about 1 min, and the outlet temperature of the air compressor was always maintained at 100 or more. It is prone to failures such as breakage of the intake valve piece and carbon deposition at the air outlet. The desiccant is easy to accumulate water and the service life is shortened. The improved system can work with the pressure drop of the air reservoir, the working interval of the air compressor increases, and the outlet temperature of the air compressor is also significantly lower than that before the improvement. The frequency of failure of the air compressor is reduced, and the service life of the desiccant is significantly increased.

Conclusion Whether it is an integral air dryer or a stand-alone air dryer, as long as the piping system is properly designed to properly sense the air pressure of the air reservoir, the normal operation of the dryer and the air brake component can be ensured. The necessary faults have occurred.

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