JPH0730120Y2 - Dry air supply device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a desiccant non-heated regeneration type dry air supply device for a communication cable, and more particularly to a freeze prevention technique in winter.

[Prior Art] A desiccant non-heated regeneration type dry air supply device is well known to those skilled in the art, but it will be briefly described as follows.

[1] Structure In FIG. 3, 12 is an air compressor, 14 is a motor, 16 is a radiator, 18 is a filter, 20A and 20B are switching valves, 22A and 22B are sorption tanks, and a desiccant is inside. It is included.

24 is an orifice, 26 is a shuttle valve, 28 is a pressure control valve, 30 is an air trap, 31 is a pressure reducing valve, and 32 is a communication cable.

[2] Action When the pressure in the air reservoir 30 drops to the lower limit, the pressure switch 34 starts the operation of the air compressor 12.

Then, for example, dry air is produced in the sorption tank 22A and stored in the air reservoir 30.

At the same time, some of the dry air produced in sorption tank 22A is further dried through orifice 24 and enters sorption tank 22B to regenerate the desiccant therein.

[3] Moisture Problem At the outlet of the air compressor 12, the temperature of the air is high and the moisture is vaporized.

The high temperature air also includes radiator 16-filter 18-switching valve 20A,
The temperature gradually decreases while passing through B, and the solidified water adheres to the filter 18, the switching valves 20A, 20B and the pipe.

When the pressure in the air reservoir 30 reaches the upper limit, the water in the filter 18 is discharged by the drainage electromagnetic valve 36, but part of the water remains inside.

Moisture in the switching valves 20A and 20B is gradually discharged to the atmosphere although part of the water is discharged to the atmosphere during the switching operation. Then, when the temperature falls below the freezing point, it freezes, causing malfunction of the switching valve.

In addition, the water attached to the pipe causes the blockage.

[4] Measures against freezing Therefore, conventionally, the temperature is controlled by providing the heater 38 and the temperature switch 40 so as to be slightly higher than the freezing point temperature.

[Problems to be Solved by the Invention] However, the conventional method requires an overheat prevention mechanism because it has a heat source, consumes a large amount of energy, and its improvement is desired.

This invention has been improved so that the heater 38 and the temperature switch 40 can be installed without installing the heater 38 and the temperature switch 40 without trouble.

[Means for Solving the Problems] As shown in FIGS. 1a and 1b, a bypass valve is provided between the inlets of the sorption tank 22A and the sorption tank 22B.
Connect via 42.

[Embodiment] [1] Configuration (1) As shown in FIGS. 1a and 1b, a bypass valve 42 (for example, a solenoid valve) is provided between the inlet side of the sorption tank 22A and the inlet side of the sorption tank 22B. Connect through.

(2) The main point of this invention is the above (1), but it is preferable to eliminate the radiator 16 and the filter 18 in the conventional example of FIG.

By doing so, the trapping of water in these portions is eliminated, and the temperature of the air flowing through the switching valves 20A, 20B becomes high (see later).

However, on the other hand, the inlet temperature of the sorption tanks 22A and 22B becomes high,
The load on the sorption tanks 22A and 22B increases. But this point is
This can be dealt with by increasing the amount of desiccant or increasing the regeneration flow rate.

(3) Also, if the filter 18 is removed, dust in the atmosphere will be sent to the cable, so a filter 44 also serving as a silencer is installed at the air intake port of the air compressor 12 to remove dust in the atmosphere. You can also take measures against noise.

[2] Operation (1) At t ₁ in FIG. 2, when P ₁ (pressure in the air reservoir 30) reaches the lower limit, the air compressor 12 starts and the switching valve 20
A and B are switched alternately.

Note that P ₀ represents the air pressure before entering the pressure control valve 28.

(2) At t ₂ , P ₁ reaches the upper limit.

Conventionally, the air compressor 12 and the switching valves 20A and 20B are stopped here, but in this case, their operation is continued and the bypass valve 42 is opened at the same time.

(3) Then, for example, in the case of FIG. 1a, the air compressor 12
The output side of the above will communicate with the atmosphere through the switching valve 20A-the bypass valve 42-the switching valve 20B (see the arrow 45 of the solid line), and the air compressor 12 will operate as a blower.

Since the air compressor 12 is warmed by the previous compression operation, the temperature of the outlet air gradually decreases, but still has a considerable height, and as a result, warm air with low relative humidity can be obtained. it can.

The warm air having a low relative humidity is blown in the switching valves 20A, 20B and the pipes, so that the insides thereof are dried.

(4) In the case of FIG. 1a, the switching valve 20A has its air inlet and sorption tank 22A port dried, and the switching valve 20B has its sorption tank 22B port and atmospheric release part dried.

Therefore, when the switching valves 20A and 20B are switched so as to be as shown in FIG. 1b (see the broken line arrow 46), the opposite sides are dried.

That is, as a result, in the case of the three-way valve as described above, if the drying is performed for one cycle or more after the pressure of the air reservoir 30 reaches the upper limit, the entire inside is dried.

(5) By using the above method, the air compressor 12
Driving time will increase.

However, there is no self-heating because it does not compress air,
It does not significantly affect the life.

[Other Embodiments] In addition to the above example, the switching valves at the inlets of the sorption tanks 22A and 22B include a combination of a two-way solenoid valve and a shuttle valve, a five-way solenoid valve, and various other types. Is used.

Even in such a case, the present invention can be applied.

[Advantages of the Invention] In the desiccant non-heated regeneration type dry air supply device, the inlets of the sorption tank 22A and the sorption tank 22B are connected through the bypass valve. By doing so, it is possible to prevent the freezing by evaporating the moisture by using the air compressor.

Therefore, conventional heating means for preventing freezing becomes unnecessary.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1a to 2 relate to an embodiment of the present invention, and FIGS. 1a and 1b are explanatory views showing the flow of hot air when the switching valve is switched, and FIG. Is a time chart, and FIG. 3 is an explanatory diagram of a conventional technique. 12: Air compressor, 14: Motor 16: Radiator, 18: Filter 20: Switching valve, 22: Sorption tank 24: Orifice, 26: Shuttle valve 28: Pressure control valve, 30: Air reservoir 31: Pressure reducing valve, 32: Communication cable 34: Pressure switch, 36: Solenoid valve for drainage 38: Heater, 40: Temperature switch 42: Bypass valve, 44: Filter 45,46: Hot air flow

Claims (1)

[Scope of utility model registration request] 1. A desiccant non-heated regeneration type dry air supply device for alternately feeding high-pressure air generated by an air compressor to a pair of sorption tanks through a switching valve. A dry air supply device in which each inlet is connected via a bypass valve.