JPH057991U - Pressure control device for air compressor with engine - Google Patents

Abstract

(57) [Summary] [Purpose] When the compressed air stored in the air tank exceeds a prescribed pressure, the slowdown operation is switched when the engine speed that drives the air compressor is reduced to perform the slowdown operation. Reduce the frequency to prolong the service life of equipment and suppress noise. [Structure] In a pressure control device for an air compressor with an engine that slows down the rotation of the engine that drives the air compressor when the compressed air stored in the air tank exceeds a predetermined pressure, the governor lever of the engine is controlled by the pilot pressure of the air tank. Is moved to the slow side, a purge valve is provided in the air tank, and compressed air is discharged from this purge valve.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a pressure control device for an air compressor with an engine, which controls the pressure of compressed air stored in an air tank in the air compressor with an engine.

[0002]

[Prior Art]

 In an air compressor with an engine, if the engine is rotated with the compressed air stored in the air tank kept above the specified pressure, the engine will be overloaded.Therefore, perform an unloader operation to open the intake valve. The pressure is controlled. In addition, since it is useless to fully rotate the engine during unloader operation, a slowdown operation may be performed in which the engine speed is also reduced.

[0003]

[Problems to be solved by the device]

 However, in such an unloader operation + slowdown operation, compressed air is not supplied to the air tank at all during the operation of the unloader. Therefore, in a mobile air compressor with a small air tank capacity, a slowdown operation is performed. Switching between operation and full throttle operation is performed too often, shortening the life of the engine, slowdown mechanism, and unloader mechanism. This invention solves such a problem, and the point is that compressed air is supplied to the air tank even at the time of slowdown operation so that the switching frequency is reduced.

[0004]

[Means for Solving the Problems]

 Under such a problem, the present invention relates to a pressure control device for an air compressor with an engine, which slows down the rotation speed of an engine that drives the air compressor when the compressed air stored in an air tank reaches a predetermined pressure or more. Provided is a pressure control device for an air compressor with an engine, in which the governor lever of the engine is moved to the slow side by the pilot pressure of the air tank, a purge valve is provided in the air tank, and compressed air is discharged from the purge valve. It was done.

[0005]

[Action]

 By taking the above means, during slowdown operation, the compressed air stored in the air tank is released into the atmosphere by the purge valve, but at this time as well, compressed air is supplied from the air compressor to the air tank. Therefore, it takes longer to switch to full throttle operation.

[0006]

【Example】

 FIG. 3 is a front view of the air compressor, and FIG. 4 is a side view of the air compressor. The air compressor is a frame 12 having wheels 10 and is provided with an engine 14, an air compressor 16, an air tank 18, etc. Type. The compressed air produced by the air compressor 16 is temporarily stored in the air tank 18 and is supplied to an external pneumatic device (not shown) via the air valve 20. The air tank 18 has a small capacity as shown in the figure, and reaches the specified pressure as soon as the consumption by the external pneumatic equipment is stopped, so at this time, it is necessary to perform some pressure control such as unloader operation.

FIG. 2 is an explanatory diagram of unloader operation + slow down operation as a conventional example of this pressure control. The air compressor 16 sucks the air that has passed through the air filter 22 by the suction valve 24, and the air is sucked by the piston. It is compressed at 26 and sent to the air tank 18 via the discharge valve 28. If the pneumatic equipment or the like continues to consume no compressed air, the compressed air in the air tank 18 reaches the specified pressure (pilot pressure), and the unloader piston 32 is operated via the unloader pilot valve 30. The suction valve 24 is opened to perform the unloader operation. On the other hand, the pilot circuit is also connected to a slowdown cylinder 36 that operates the governor lever 34 of the engine 14, and when pilot pressure is applied, this slowdown cylinder 36 is operated to move the governor lever 34 to the slow side, where the slowdown is performed. Drive. When the pressure of the compressed air in the air tank 18 falls below the specified pressure, the unloader piston 32 and the slowdown cylinder 36 stop their operations, and the engine 14 restarts full throttle operation.

FIG. 1 is an explanatory view showing an embodiment of the present invention, except that the unloader piston 32 is eliminated and a purge valve 38 is attached to the air tank 18 instead of the unloader piston 32. When the compressed air in the air tank 18 reaches the purge pressure (which is set to the same level as the pilot pressure), the purge valve 38 releases the compressed air to the atmosphere. The slowdown mechanism is left as it is, and the slowdown operation is performed at the time of release.

[0009]

[Effect of the device]

As described above, since the present invention has been described above, the following effects can be expected. a) The interval time for switching the engine speed is longer than that of the conventional unloader operation + slowdown operation, and the life of the engine and the slowdown mechanism is extended. As an example, the air tank 10L, the compressed air discharge quantity during the engine full throttle 400 L / min, the compressed air discharge rate 300L / min during slowdown, the working air rate 350L / min, the operating pressure 6~7Kg / cm ² Then, the time for one cycle is 10 × 1 / (400−350) + 10 × 1 / (350−300) = 24 sec. On the other hand, in the conventional unloader operation + slowdown operation, since the compressed air discharge amount is 0, it becomes 10 × 1 / (400−350) + 10 × 1/350 = 14 sec. From this, it can be seen that according to the present invention, the switching time between the full throttle operation and the slowdown operation becomes long, and the life of the engine, the slowdown mechanism and the slowdown mechanism is extended accordingly. b) When the amount of air used is small (300 L / min or less in the above example), the engine only needs to be in slow-down operation at all times, which is economical in terms of fuel consumption and the engine and compressor. The durability is improved. In particular, in this case, the noise can be suppressed to a low level, and there is a remarkable effect that noise troubles at work sites, which have recently become a problem, are reduced. c) Since an unloader mechanism such as an unloader piston is unnecessary, the structure is correspondingly simplified and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is an explanatory view of a pressure control device according to the present invention.

FIG. 2 is an explanatory diagram of a conventional pressure control device.

FIG. 3 is a front view of the air compressor.

FIG. 4 is a side view of the air compressor.

[Explanation of symbols]

 14 engine 16 air compressor 18 air tank 34 engine governor lever 38 purge valve

Claims (1)

[Claims for utility model registration] 1. When the compressed air stored in the air tank (18) exceeds a predetermined pressure, the rotational speed of the engine (14) for driving the air compressor (16) is slowed down. In a pressure control device for an air compressor with an engine, the engine (14) is operated by a pilot pressure of the air tank (18).
Move the governor lever (34) of
A pressure control device for an air compressor with an engine, wherein a purge valve (38) is provided in the air tank (18), and compressed air is discharged from the purge valve (38).