JPH06174191A - Control circuit for electrically operated drain trap in air compressor - Google Patents

Abstract

PURPOSE:To improve reliability of operation, such as that a compressor can be operated even at trouble time of an electrically-operated drain trap, by providing a pressure switch in a delivery pipe or an air tank, and electrifying each electrically-operated drain trap placed in an operating condition when actuated the pressure switch. CONSTITUTION:When a power supply switch 11 of an air compressor is closed, an electric motor 3 is rotated to actuate an air compressor 2, and the atmospheric air is sucked to discharge compressed air to an air tank 1. Here in a work machine side which is a demand side, when a delivery pipe 4 of compressed air is closed, the air compressor is continued to operate before leading to the upper limit pressure (for instance, 10kg/cm<2>), to accumulate the compressed air in the air tank 1. During this boosting action, when a normally- opened contact 13a is closed at the upper limit preset pressure (for instance, 5kg/cm<2>), in a pressure switch 13 interposed in the delivery pipe 4 in the downstream of a drier 5, electrically-operated drain traps 9-1, 9-2 are electrified so as to be actuated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is provided with a device for discharging drain such as an aftercooler, a drain separator, an air tank, and an air dryer in an air tank and a discharge pipe. The present invention relates to a control circuit for an electric drain trap in an air compressor in which a dryer has an electric drain trap.

[0002]

2. Description of the Related Art A conventional example in which an electric drain trap which opens at a time interval and closes again at a time by an internal timer when energized is used as a discharge device in an air compressor. Has a control circuit as shown in FIG.

In FIG. 7, an electric motor 3 and an air compressor 2 connected by a belt device are provided on the air tank 1, and a discharge port of the air compressor 2 communicates with the air tank 1. The air tank 1 is connected to a device using compressed air through a compressed air discharge pipe 4.

In this case, various dehumidifiers are arranged in the compressed air discharge pipe 4 between the normal air tank 1 and the equipment using compressed air in order to reduce the humidity of the air and remove the adverse effect on the equipment using compressed air. The example of the drawing shows an example in which a dryer 5 is arranged in the compressed air discharge pipe 4. As a device for discharging drain, an aftercooler, a drain separator, or the like may be installed.

Then, these air tank 1 and dryer 5
Drain is discharged from the above, etc., but the lubricating oil entrained from the air compressor 2 is mixed into this drain during air compression,
Contains oily water. A stop valve 8 and electric drain traps 9-1 and 9-2 are provided in the drain pipes 6 and 7 of the air tank 1 and the dryer 5, respectively. Although not shown, the outlets of the electric drain traps 9-1 and 9-2 communicate with a drain storage tank or a drain processing device.

The power source of the electric drain trap 9-1 is connected to the secondary side of the power switch 11 of the air compressor. When the power switch 11 of the air compressor is turned on, the air compressor is started, and the electric drain trap 9-1 also. It turns on.

The power source of the electric drain trap 9-2 is equipped with a power switch 12 dedicated to the drain trap.
In addition to turning on the power switch 11 of the air compressor, the power switch 12 of the electric drain trap 9-2 is turned on.

[0008]

When the electric drain trap 9-1 for the air tank is wired on the secondary side of the power switch 11 of the air compressor, the power switch of the air compressor cannot do its work unless the air compressor operates. So don't forget to turn on the power switch of the air compressor. At the same time, the electric drain trap for the air tank attached to the air compressor will be turned on, which is very convenient. When a failure or short circuit occurred, the breaker of the power switch of the air compressor was turned off, the air compressor was stopped, and the work was often interrupted.

On the other hand, it is easy to forget to operate the dedicated power switch 12 of the electric drain trap 9-2 provided for the dryer. When the power switch 12 was forgotten to be turned on and the air compressor continued to operate, a large amount of drain was accumulated in the dryer 5, etc., and it was often noticed only after the drain came out from the pneumatic equipment using compressed air. . Further, after the work is completed, the mistake of forgetting to turn off the power switch 11 for the air compressor rarely occurs, but it is easy to forget to turn off the power switch 12 for the electric drain trap such as the dryer. If you forget it, it will be useless to just activate the electric drain trap for the dryer.

According to the present invention, a failure of an electric drain trap provided in an air tank of an air compressor does not affect a power switch of the air compressor, and an electric drain trap provided in a device for generating a drain provided in a discharge pipe is provided. The above-mentioned problems are solved by enabling both electric drain traps provided in the air tank of the present invention to operate at the same time and operating both electric drain traps only when the discharge pressure of the air compressor is generated. An object of the present invention is to provide a control circuit for an electric drain trap in an air compressor in which an electric drain trap is provided in a device for generating a drain inserted in a pipe.

[0011]

DISCLOSURE OF THE INVENTION The present invention relates to an apparatus for generating drain from compressed air such as a dryer installed in an air tank and a discharge pipe, and an apparatus for generating drain, including at least an air tank. In a control circuit of an electric drain trap in an air compressor that has an electric drain trap provided in each of the devices that generate two drains, a pressure switch is installed in the discharge pipe or the air tank, and the pressure switch is operated by compressed air pressure. In an operating state, each electric drain trap is energized to be in an operating state, which is a control circuit for an electric trap in an air compressor.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

[Embodiment 1] The air compressor and its compressed air circuit are the same as those of the conventional example, and are similarly provided with an electric drain trap 9-1 for an air tank and an electric drain trap 9-2 for a dryer. These points will be explained in the description of the conventional example.

FIG. 1 shows an embodiment of the present invention. The air compressor is equipped with a pressure switch for keeping the pressure of the compressed air produced by the air compressor within a certain range, and with an unloader device. In the case of the pressure switch type control, a pressure switch is usually attached to the air tank 1, the compressed air pressure in the air tank 1 is, for example, 10 kg / cm ² , and the electric motor 3 is stopped.
When it falls below g / cm ² , the electric motor 3 is energized. In the case of an unloader type compressor equipped with an unloader device, when the compressed air pressure reaches 10 kg / cm ² , no load occurs and no compressed air is produced. And the compressed air pressure is 8
When it reaches kg / cm ^2, it becomes a loaded state and produces compressed air. A pressure switch 13 is provided in the compressed air discharge pipe 4 downstream of the dryer 5. If the lower limit pressure of the on / off control of the air compressor is set to 8 kg / cm ² as described above, the lower limit pressure of the pressure switch 13 is 8 k.
It is set to operate at an upper limit pressure lower than g / cm ² . For example, when the compressed air pressure rises, it is turned on at 5 kg / cm ² , and when it decreases, 3 k
It is designed to turn off at g / cm ² .

The pressure switch 13 is provided with a normally open contact 13a. The normally open contact 13a of the switch 13 is connected to a power source 20. The secondary side of the normally open contact 13a is electrically connected in parallel to an electric drain trap 9-1. It is wired to 9-2.

The operation of the above configuration will be described. When the power switch 11 of the air compressor is turned on, the electric motor 3 is rotated and the air compressor 2 is actuated, sucking the atmosphere and sucking the air tank 1.
Discharge compressed air to. Since the upper limit pressure of the air compressor is set to 10 kg / cm ² , if the compressed air discharge pipe 4 is closed on the side of the working machine that uses compressed air, it will continue until the compressed air pressure reaches this upper limit pressure. The compressed air pressure in the air tank 1, the discharge pipe 4, and the dryer 5 also continuously rises at the same pressure.

When the compressed air pressure in the discharge pipe 4 rises to the upper limit set pressure of 5 kg / cm ² of the pressure switch 13 that constantly receives the pressure of compressed air, the normally open contact 13a closes.
The power source 20 simultaneously communicates with the electric drain traps 9-1 and 9-2, and the electric drain traps 9-1 and 9-2 are activated. The compressed air in the air tank 1 has risen in temperature due to the compression of air by the air compressor 2, and the compressed air in the air tank 1 radiates heat via the air tank 1 to lower its temperature.
Moisture in the compressed air taken from the atmosphere becomes saturated vapor and is further condensed to become liquid, which accumulates on the bottom of the air tank 1. The liquid phase water is mixed with the lubricating oil of the air compressor 2 to contain oil muddy water, which is a so-called drain. Further, the dryer 5 positively removes the water in the compressed air, so that drainage is generated. The stop valve 8 normally remains open,
The electric drain traps 9-1 and 9-2 are intermittently opened by a built-in timer to discharge the drain.

As described above, since the electric drain trap 9-1 for the air tank 1 and the electric drain trap 9-2 for the dryer are operated by one operation of the power switch 11,
It is prevented that the power switch 12 dedicated to the electric drain trap 9-2 for the dryer is forgotten to be turned on and the drain is accumulated in the dryer 5 and air with a large amount of moisture is sent from the discharge pipe 4 to the working machine. Further, since the pressure switch 13 is arranged in the discharge pipe 4 on the downstream side of the dryer 5, the electric drain traps 9-1 and 9 are provided when it is forgotten to open the sluice valve 10 that connects the air tank 1 and the discharge pipe 4. There is no waste of operating -2.

When the power switch 11 is turned off, the electric motor 3 is stopped, the air compressor is deactivated, and the discharge pipe 4
When the compressed air pressure in the inside becomes 3 kg / cm ² , the normally open contact 13a of the pressure switch 13 is opened and the electric drain traps 9-1 and 9-2 are cut off. By forgetting to operate the electric drain trap 9-2, there is no waste of being in the energized state.

[Second Embodiment] FIG. 2 shows a second embodiment. Aftercooler 14 and drain separator 1 are provided in discharge pipe 4.
5, the dryer 5, and the pressure switch 13 are provided in this order from the upstream side to the downstream side. Electric drain traps 9-1, 9-2, 9-3, 9-4 are provided in the air tank 1 and the above-mentioned drain generating devices 14, 15, 5 respectively.
The pressure switch 13 is arranged in parallel on the secondary side of the normally open contact. The operation is the same as in the previous embodiment, and the operation of the air compressor increases the compressed air pressure in the pressure switch 13 so that all electric drain traps 9-1, 9-2, 9-3,
9-4 is energized, and all the electric drain traps 9-1, 9-2, 9-3, 9-4 are deenergized due to the decrease in compressed air pressure.

[Third Embodiment] FIG. 3 shows a third embodiment. Aftercooler 14 and drain separator 1 are provided in discharge pipe 4.
5, the dryer 5, and the mist separator 16 are interposed in this order in the flow direction of the compressed air. As in the previous embodiments, a pressure switch 13 is arranged in the discharge pipe 4 on the downstream side of the dryer 5, and an electric drain trap 9-1 is arranged in the air tank 1. In the previous embodiment, the number of electric drain traps is large and uneconomical. Electric drain trap 9-
1, 9-2 are wired in parallel from the pressure switch 13.

In this embodiment, the drain outlets of the aftercooler 14 and the drain separator 15 are connected to the two inlets 23 and 24 of the shuttle valve 17, respectively, and the drain outlets of the dryer 5 and the mist separator 16 are connected to the shuttle valve 18. Connected to the two inlets 23 and 24 respectively, and further to the shuttle valves 17 and 1
The drain outlets 25 and 25 of the shuttle valve 19 are connected to the drain inlets 23 and 24 of the shuttle valve 19, respectively, and the drain outlet 25 of the shuttle valve 19 communicates with the electric drain trap 9-2.

4, 5 and 6 are longitudinal sectional views of the shuttle valve.

The operation of the shuttle valve 17 will be described with reference to FIGS. When compressed air is used on the load side, the compressed air in the air tank 1 passes through the compressed air discharge pipe 4, passes through the aftercooler 14, the drain separator 15, the dryer 5, and the mist separator 16, and cools and drains. After drying and removing oil mist, the product is fed, and drainage occurs in these devices. The compressed air pressure in each device is gradually lower from the upstream side toward the downstream side. Therefore, when the electric drain trap 9-2 is closed, the compressed air pressure in the aftercooler 14 is increased by the drain separator 15.
Since it is higher than the compressed air in the shuttle valve 17, the inlet 23 of the shuttle valve 17 has a higher pressure than the inlet 24, and the valve body 28
As shown in FIG. 4, the valve goes rightward to contact the valve seat member 26b, closes the valve opening 26d, does not apply pressure from the drain outlet of the aftercooler 14 to the drain separator 15, and drains into the drain separator 15. There is no backflow. Further, a rapid increase in pressure generated when the air circuit is closed on the load side is transmitted as a wave in the compressed air discharge pipe 4 in a direction opposite to the flow direction of the compressed air. In that case, the pressure generated in the drain separator 15 is after-sales. It becomes higher than the compressed air pressure in the cooler 14, and joins the valve body 28 from the drain discharge port of the drain separator 15 through the inflow port 24.
8 is moved leftward as shown in FIG. 5 and pressed against the valve seat member 26a, and the valve port 26c is closed by the valve body 28, so that the drain does not blow up into the aftercooler 14.

In any state, when the electric drain trap 9-2 is opened, the drain from the devices 14 and 15 connected to the inlet 23 or 24 is shut off by the shuttle valve 1.
7 flows out from the valve chamber 27 of the No. 7 through the outlet 25 and is discharged to the same processing device as the atmospheric pressure. Alternatively, from the state of FIG. 5, the valve body 28 is at the intermediate position as shown in FIG. 6, and the drain is discharged.

As described above, the after cooler 1
4. The conventional electric drain traps 9-3 and 9-4, which are respectively provided in the drain separator 15 and the like, are integrated into one and can be replaced by an inexpensive shuttle valve. Since the shuttle valve has no directivity with respect to the inflow port, it can be mounted in any direction in the pipe, and the pipe will not be mistaken.

A shuttle valve 18 having inlets connected to the drain discharge ports of the dryer 5 and the mist separator 16 respectively.
Also works similarly. So next shuttle valve 1
Since the drain discharge ports of Nos. 7 and 18 are connected to the respective inlets of the shuttle valve 19, the shuttle valve 19 operates similarly according to the pressure of the drain discharged from the shuttle valves 17 and 18, and one electric drain trap 9 -2 allows the drains of the devices 5, 14, 15, 16 for discharging the drains to be discharged.

Although the third embodiment uses the shuttle valve, a valve capable of selectively discharging a plurality of drain inlets to one drain outlet may be used, and the number of electric drain traps is reduced as in the third embodiment. it can.

In each of the embodiments, since the pressure switch is provided on the downstream side of the drain discharge device, the compressed air pressure in the drain discharge device can be confirmed. However, for the purpose of the present invention, the pressure switch 13 is an air switch. The same effect can be achieved even if it is installed in any place after the air tank including the tank.

[0030]

The present invention relates to an electric drain trap for drain discharge attached to an air tank of an air compressor,
Equipped with an electric drain trap that discharges the drain from the device that discharges the drain installed in the compressed air discharge pipe, has a pressure switch that is operated by the compressed air, and connects the electric drain trap in parallel with the pressure switch. Since it is operated, the electric drain trap for the air tank is operated by wiring from the secondary side of the power switch of the air compressor, as in the conventional example, such as a short circuit of the electric drain trap attached to the air tank. Since the breaker of the power switch of the air compressor does not operate due to the failure of 1., there is no possibility that the power cannot be turned on and the air compressor cannot be used due to the failure of the electric drain trap for the air tank. Further, there is an effect that forgetting to turn on the power of the electric drain trap for discharging the drain discharged from the device for generating the drain interposed in the discharge pipe and forgetting to turn it off. Further, since the pressure switch is arranged at a portion where compressed air is generated, the air compressor is operating but the compressed air is not generated.For example, the belt is loosened between the electric motor and the air compressor, or the air compressor fails. In the case where only a small amount of compressed air pressure is generated, none of the electric drain traps work, so there is no waste of working the electric drain trap in the state where no drain is generated.

[Brief description of drawings]

FIG. 1 is a flow sheet of Example 1 of the present invention.

FIG. 2 is a flow sheet of Example 2 of the present invention.

FIG. 3 is a flow sheet of Example 3 of the present invention.

FIG. 4 is a vertical sectional view showing the operation of the shuttle valve.

FIG. 5 is a vertical sectional view showing the operation of the shuttle valve.

FIG. 6 is a vertical sectional view showing the operation of the shuttle valve.

FIG. 7 is a flow sheet of a conventional example.

[Explanation of symbols]

 1 Air Tank 4 Compressed Air Discharge Pipe 5 Dryer 11 Air Compressor Power Switch 13 Pressure Switch 15 Drain Separator 16 Mist Separator

Claims (1)

[Claims] 1. A device for generating drain from compressed air such as a dryer installed in an air tank and a discharge pipe, and a device for generating at least two drains, including an air tank, among devices for generating drain. In the control circuit of the electric drain trap in the air compressor having the electric drain trap provided in each, each electric type when the pressure switch is installed in the discharge pipe or the air tank and the pressure switch is operated by the compressed air pressure. A control circuit for an electric trap in an air compressor, wherein a drain trap is energized to be in an operating state.