JPS595200B2 - Automatic drain discharge device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention allows drains in the air tank and upper tube of a pressure switch type air compressor to be drained for a short period of time each time the air compressor is started while the air compressor is in operation. , the power supply circuit breaking layer of the air compressor drive motor is concerned with an automatic drain evacuation device that can continuously discharge the drain and compressed air.

Some inventions related to this, for example, include a system that includes a float and discharges the drain when the float rises above a certain water level, and stops draining when the float sinks below a certain water level.

Therefore, since drains below a certain water level cannot be discharged, there is always a drain below a certain water level.

There is also a device that uses a repeat timer to control a normally closed solenoid valve (a solenoid valve that is normally closed and opens when current flows) to periodically discharge the drain for short periods of time.

In this case, the drain can be discharged while the air compressor is in operation, but after the power supply circuit of the air compressor drive motor is cut off and the air compressor is stopped, the drain cannot be discharged because power cannot be transmitted to the solenoid valve.

Therefore, after the air compressor is stopped, the compressed air in the air tank cools and the drain generated remains in the air tank.

Due to improvements in piping technology in recent years, there is less leakage of compressed air.
Even when the air compressor is stopped after work is completed and the empty compressor is started the next morning, the residual pressure of the compressed air in the air tank is high.
The air compressor has been idle for a long time, so the sliding parts are running out of oil.

When an air compressor is started under the load of this lack of oil and high residual pressure, the sliding parts will wear out and electrical equipment will often be damaged.

In addition, during the cold season, residual drains freeze, damaging the pipes and blocking the inside of the pipes, making it difficult to use compressed air the next morning.

In view of this point, the present invention periodically discharges the drain for a certain period of time while the air compressor is in operation, and when the work is finished, the power cutoff layer leaves the valve open to completely eliminate the drain and compressed air. We believe that this is the most rational method, and at the same time, in order to make the automatic drain discharge device economical, we share the pressure switch required for pressure switch type air compressors, and use an economical limited-time normally open bimetal thermal timer. By controlling the open solenoid valve (a solenoid valve that is always open and closes when current flows), when the air compressor is operating, the drain in the air tank is closed for a certain period of time each time the air compressor is started. It has the effect of automatically discharging the air tank at all times to keep the air tank highly clean, and at the same time shuts off the power circuit of the air compressor pivot motor to stop the air compressor, and at the same time, the normally open solenoid valve keeps the valve open. By doing so, the drain and compressed air in the air tank are released and completely eliminated, and the next air compressor can be started without any load. Also, since there is no trone, there is no need to worry about freezing during the cold season. The purpose of the present invention is to obtain an automatic drain discharge device having the following functions.

This will be explained below with reference to FIG.

First, a pressure switch type air compressor will be explained.

Reference numeral 1 denotes an electric circuit switch for an electric motor 2 that drives an air compressor 3.

5 is an air tank connected to the air compressor 3 via piping 4.

9 is an air pipe for sending compressed air to the outside.

Discharging the drain in the air pipe 9 is completely the same as the present explanation for discharging the drain in the air tank, so the explanation will be omitted.

20 is a pressure switch attached to the air tank 5.

The electrical circuit for pressure switch 20 is shown at the top of FIG.

That is, the electric motor 2 is connected to the power source through the normally closed contact 23, the movable contact 22, and the common terminal 21 of the pressure switch 20.

The pressure switch 20 is configured such that the movable contact 22 keeps the normally closed contact 23 closed to rotate the electric motor 2 until the air pressure in the air tank 5 reaches a preset upper limit. When the exit value is reached, the movable contact 22 opens the normally closed contact 23 and holds the normally open contact 24 closed as shown by the dotted line, and the motor 2 stops rotating.

When the air pressure in the air tank 5 falls to a preset lower limit value, the movable contact 22 returns to the normally closed contact 23 and the electric motor 2 resumes rotation.

As described above, the normally closed contact 23 and the normally open contact 24 of the pressure switch 20 are repeatedly opened and closed.

8 is a normally open solenoid valve (a solenoid valve that is normally open and closes when current flows), and its drain is connected to the bottom of the air tank 5 through a drain pipe 6.

7 is a discharge pipe through which the normally open solenoid valve 8 discharges the drain to the outside.

3o is a time-limited normally open bimetal thermal timer, which consists of a time-limited normally open contact 31 and a heater 34.

The heater 34 is connected to the normally closed contact 23 and the power source.

The normally open solenoid valve 8 is connected to the power supply circuit of the motor 2 through a normally open contact 24, a movable contact 22 (indicated by a dotted line), and a common terminal 21.

This electric circuit will be called a circuit.

In addition, the normally open solenoid valve 8 has a limited time normally open contact 31 and a common terminal 21.
It is connected to the power supply circuit of the electric motor 2 through the .

This electric circuit will be called 8 circuits. The operation will be explained with reference to the drawings.

When the circuit switch 1 is closed, the electric motor 2 drives the air compressor 3, and the air compressor 3 starts supplying compressed air to the air tank 5.

At the same time, the current flows through the common terminal 21 movable contact 22 and normally closed contact 2
3 and flows to the heater 34 to be heated.

However, since the time-limited normally open contact 31 and the normally open contact 24 are open, no current flows from the circuit 8, and the normally open solenoid valve 8 opens to drain the drain in the air tank 5 from the discharge pipe 7. Discharge.

When the scheduled time has elapsed, first, the time-limited normally open contact 31 is heated by the heater 34 and closes the contact, so the current flows from the 8 circuits to the normally open solenoid valve 8, and the normally open solenoid valve 8 closes. Stop.

On the other hand, since current is flowing to the electric motor 2, the air compressor 3 is being driven, and the air compressor 3 continues to fill the air tank 5 with compressed air, but the air pressure eventually reaches the upper limit. 22 opens the normally closed contact 23 and closes the normally open contact 24 as shown by the dotted line, so the electric current is cut off to the electric motor 2 and the drive of the air compressor 3 is stopped, and the air compressor 3 transfers the compressed air to the air tank 5. Stop what is filling.

On the other hand, the current is also cut off to the heater 34, but the time-limited normally open contact 31 still remains closed for preheating, so current flows from both AtB circuits and the normally open solenoid valve 8 stops drain discharge. There is.

The heater 34 whose current is cut off gradually cools down, and after a predetermined time has elapsed, the time-limited normally open contact 31 returns to its original open position, and the eight circuits become open.

When the air pressure in the air tank 5 drops to the lower limit due to the use of compressed air, the movable contact 22 opens the normally open contact 24 and returns to the normally closed contact 23, but since the normally open contact 31 is open for a limited time, , B circuits are open, no current flows, and the normally open solenoid valve 8 is opened to start draining.

At the same time, the current flows to the heater 34 and heats it, and when the predetermined time has elapsed, the time-limited normally open contact 31 closes the contact, so that current flows from the 8 circuits and the normally open solenoid valve 8 stops drain discharge.

On the other hand, the current flows to the electric motor 2 and drives the air compressor 3,
The air compressor 3 starts filling the air tank 5 with compressed air.

Therefore, while the circuit breaker 1 is closed, the movable contact 22
In other words, every time the motor 2 closes the normally closed contact 23,
The normally open solenoid valve 8 can discharge the drain for a scheduled time every time the circuit is started, and while the circuit breaker 1 is open, no current flows in both circuits A and B, so the normally open solenoid valve 8 is normally open. The solenoid valve 8 remains open.

Next, the point that the normally open solenoid valve 8 can periodically open and close to discharge the drain will be explained in detail.

In the pressure switch 20, the operating time during which the movable contact 22 closes the normally closed contact 23 is T1, and the return time from when the normally closed contact 23 opens and the normally open contact 24 closes to when the normally closed contact 23 returns. Let be T2.

The operating time during which the time-limited normally open contact 31 opens the contact is tl, and the return time from when the first normally closed liquid point 23 opens until the time-limited normally open contact 31 opens the contact is t2.

Generally, in pressure switch type air compressors, T1 and T2 are several minutes or more.

According to the results of experiments, although it depends on the capacity of the air compressor and the conditions of use, it is appropriate that tl is 5 seconds to 30 seconds and t2 is within 90 seconds, and manufacturing is possible.

Therefore, the relationship T1, t1e, T2, and t2 is established.

Therefore, when the motor 2 is started, both circuits A and B are open, no current flows, and the normally open solenoid valve 8 is open.
Drain can be discharged.

On the other hand, the current flows from the normally closed contact 23 to the heater 34 for heating.Due to the relationship between the operating time T1 and t1, the time-limited normally open contact 31 closes the double contact for t1 seconds from the time of startup, so the current flows from the 8 circuits and normally The open solenoid valve 8 stops drain discharge.

While the normally closed contact 23 is closed, the heater 34 is heated and the time-limited normally open contact 31 is closed, so the normally open solenoid valve 8 continues to stop discharging the drain.

From the time of startup, the movable contact 22 opens the normally closed contact 23 and closes the normally open contact 24 for T1 minutes.

From this point on, the time-limited normally open contact 31 is closed for the return time t2 seconds, so both circuits A and B are closed, and the normally open solenoid valve 8 continues to stop drain discharge.

From the relationship of the return time T2 and t2, first, the time-limited normally open contact 3
1 opens the contact, so the 8 circuit becomes an open circuit.

From the time of startup (TI+T2), the movable contact 22 opens the normally open contact 24 and returns to the normally closed contact 23, so both A and B circuits become open, and the normally open solenoid valve 8 and the normally open contact 31 at the time of snacking operate. The drain can be discharged for a time t1 seconds.

At the same time, the electric motor 2 drives the air compressor 3 to resume filling the air tank 5 with compressed air.

Therefore, while the circuit switch 1 is closed, the normally open solenoid valve 8 can discharge the drain for t1 seconds each time the electric motor 2 drives the empty compressor 3.

This relationship is shown in FIG. At the end of the day's work, when I open circuit switch 1, A appears.

Since no current flows in both B circuits, the normally open solenoid valve 8 remains open and releases the drain and compressed air until it is completely exhausted, so the air compressor can be started with no load the next morning, and is useful in cold weather. It does not freeze even at night because there are no drains.

Timed normally open bimetallic thermal timers are economical and
By selecting the optimum operating time t1 and return time t2 according to the capacity of the air compressor and usage conditions, no drain will be left in the air tank, and compressed air will be discharged to the outside unnecessarily. It can also be prevented.

Therefore, the present invention is an extremely simple automatic drain discharging device that shares the pressure switch necessary for a pressure switch type air compressor and controls a normally open solenoid valve with an economical, limited-time normally open bimetal thermal timer. Nevertheless, while the air compressor is in operation, the air tank is automatically discharged for a certain period of time each time the air compressor is started, keeping the air tank highly clean. To maintain the effect of keeping the air compressor working body shut down, leave the normally open solenoid valve open, release the drain and compressed air, and eliminate the air compressor. It has the effect of preventing wear on the sliding parts and damage to electrical equipment, and since there is no drain, there is no need to worry about freezing at night during the cold season. It is extremely useful as an automatic drain discharge device.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of an automatic drain discharge time of the present invention attached to an air tank of a pressure switch type air compressor. FIG. 2 illustrates the relationship between the Draey discharge cycle and the discharge time.

Claims (1)

[Claims] 1 Electric motor 2 whose power supply is opened and closed by a pressure switch 20
an air compressor 3 driven by the air compressor 3, a normally open solenoid valve 8 connected to an air tank 5 to which compressed air is supplied from the air compressor 3, a normally open only time contact 31, and a heater 34. The electric circuit of the normally open solenoid valve 8 is connected to the power supply circuit of the electric motor 2 through the time-limited normally open contact 31 and the common terminal 21 of the pressure switch 20, and the normally open contact 24 of the pressure switch 20, the movable contact 22, and Common terminal 2
1 and the electrical circuit of the normally open solenoid valve 8 connected to the power supply circuit of the electric motor 2, the electrical circuit of the heater 34 which shares the normally closed contact 23 of the pressure switch 20, and the pressure switch 20.
A circuit for controlling the normally open solenoid valve 8 is configured, and the operating time T1 and return time T of the movable contact 22 of the pressure switch 20 are
2 and time-limited normally open contact 31 operating time j1 % return time t
2. An automatic drain discharge device characterized in that a relationship of T1 and t1 and T2 and t2 is established between the two.