JPH0344828B2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention is capable of automatically and instantaneously switching between cold and hot water, and also enables rational switching of cold and hot water according to actual use. This invention relates to a cold/hot water switching device.

(Prior art) For example, hot water car wash machines are often used to wash vehicles because hot water has a higher cleaning ability than cold water. However, when removing dirt, sand, etc., it is generally necessary to spray cold water at high pressure. This is sufficient, so when actually washing a large car, etc., wash only the areas with oil or grease, such as around the engine, front and rear axles, with warm water, and wash the body, frame, etc. with cold water. A method has been adopted to do so.

Therefore, during actual washing, it is necessary to quickly switch between hot and cold water, but conventionally, this type of car wash machine has not been equipped with an appropriate cold/hot water switching device, so it is generally necessary to switch between hot and cold water. A method such as connecting a stop gun to a cold water source has been adopted, and in addition to the complicated connection work, switching between cold and hot water takes time and effort, making it impossible to wash cars efficiently.

By the way, there is a technique disclosed in Japanese Utility Model Application Publication No. 59-24183 that aims to improve the efficiency of such car washing operations. That is, in this publication, a stop gun is equipped with a transmitter that makes full use of a piezoelectric element, a control circuit for a cleaning water delivery pump is connected to this transmitter, and the voltage generated by operating the handle of the stop gun is applied to the control circuit. , shows a remote control device for a washing machine that controls ON/OFF operation of the pump.

(Problem to be Solved by the Invention) However, with this control device, although it is possible to easily control the operation of the wash water delivery pump by operating the handle of the stop gun, it is only possible to switch between spraying and stopping cold water or hot water. Therefore, not only is it impossible to handle both hot and cold water and use them selectively and easily, but also the configuration of the stop gun and control circuit becomes complicated, making this type of device expensive.

The present invention solves these conventional problems, allows both hot water and cold water to be used selectively as appropriate, switches between them instantaneously and automatically, and streamlines the switching according to actual usage. It is an object of the present invention to provide a cold/hot water switching device that can switch between cold and hot water.

(Means for Solving the Problems) Therefore, the cold/hot water switching device of the present invention includes a directional control valve that communicates with a cold water source and a hot water source and can selectively switch between the cold and hot water; A control switch installed in a bypass pipe communicating with the outlet side pipe, which detects a predetermined momentum of cold and hot water moving in the pipe and outputs a signal, and switches the directional control valve in conjunction with the signal from the switch. The system is equipped with a drive system that enables automatic and instantaneous switching between cold and hot water, allowing car washes to perform optimal and rational cleaning depending on the area to be washed and the level of dirt. It is characterized by

In addition, in the present invention, a directional control valve that communicates with a cold water source and a hot water source and can selectively switch between the cold and hot water is installed in a bypass pipe that communicates with an outlet side pipe of the valve, and is moved within the pipe. It is equipped with a control switch that detects a predetermined momentum of cold and hot water and outputs a signal, and if the time required to turn ON/OFF the switch is within a predetermined time, the cold and hot water can be switched, while the above-mentioned required time is When the time is longer than a predetermined time, switching between cold and hot water is disabled and the original water supply mode is maintained, so that switching between cold and hot water is controlled according to the actual use. .

(Example) Hereinafter, an illustrated example in which the present invention is applied to a hot water car wash machine will be described. In Figs. 1 to 3, 1 is a float tank installed in the car wash machine,
One end of a water supply pipe 2 communicating with a cold water source is connected to its upper part, and a float valve 4 that opens and closes a discharge port in conjunction with the displacement of the float 3 is provided at the end of the pipe.

One end of the connecting pipe 5 is attached to the lower part of the float tank 1, and the other end is connected to a boiler 6 which is a hot water source.
It is connected to the side end face of and communicates with the internal water space. The boiler 6 has a horizontal double can structure, and a water space capable of containing supply water is provided between the inner and outer double cans.
Further, a burner 7 is provided in the opening of the central heating can.

One end of a hot water pipe 8 is connected to the upper side end surface of the boiler 6 that communicates with the water space, and one end of a cold water pipe 9 is connected to the lower part of the water tank 1. The valve 10 is connected to each port of a rotary three-way valve in the embodiment. Rotary valve 10 constituting directional control valve 10
A connecting rod 11 is protruded from the coaxial peripheral surface of a, and a cylinder 12 constituting a drive system is installed at the tip of this connecting rod 11.
One end of the piston rod 13 is connected,
The rotary valve 10a can be driven.

In the case of the embodiment, the cylinder 12 is a pneumatic cylinder, and one end of the air supply pipes 14a, 14b is connected to the air supply ports opened at both ends of the cylinder tube, and the drive system is configured at the other end. A solenoid valve 15 is connected. The cylinder 12 is normally connected to the piston rod 1.
3 is retracted to set the directional control valve 10 to the cold water conduction mode, and when pressurized air is supplied from the solenoid valve 15 via the air supply pipe 14a, the piston rod 13 is protruded and the directional control valve 10 is set to the cold water conduction mode. 10
can be switched to hot water conduction mode.

A pneumatic pipe 16 that communicates with an air pressure source is connected to the solenoid valve 15, and its operation is controlled by a flow switch described later. Normally, the pneumatic pipe 16 and the air supply pipe 14b are in communication, and the piston rod 13 into the cylinder 12,
The cold water conduction mode of the directional control valve 10 is established. In the figure, 17 is a piston slidably housed in the cylinder 12, and 18 is cold water as cleaning water housed in the float tank 1.

The directional control valve 10 has a plurality of ports P ₁ , P ₂ , P ₃
A common port _P3 is provided between the cold water port _P1 and the hot water port _P2 , and one end of the suction pipe 19 is connected to this port _P3 , and the other end is connected to a drive pipe. A water pump 21 directly connected to the motor 20 is connected. Water supply pump 21
A water supply hose 23 is connected to the discharge pipe 22, and a stop gun 24 is connected to the hose 23. By operating a trigger 25 of the stop gun 24, cleaning water can be sprayed from a nozzle 26 at the tip.

Further, a bypass pipe 27 is installed between the discharge pipe 22 and the water space of the boiler 6,
A relief valve 28 and a flow switch 29 as a control switch are inserted into the pipe 27. Among these, the flow switch 29 operates by detecting a predetermined momentum of cold and hot water passing through the interior, that is, one of the flow rate, pressure, and flow velocity, in the embodiment, the flow rate,
The signal is outputted to the control circuit of the solenoid valve 15, which will be described later. In the embodiment, one end of the movable piece linked to the actuating piece of the microswitch is made to face inside the bypass pipe 27 as means for detecting the amount of momentum. There is.

In addition, reference numeral 30 in the figure is an operation panel installed at the car wash, on which are installed a manual/automatic changeover switch 31, a switch 32 for the water supply pump 21, a cold water indicator lamp 33, and a hot water indicator lamp 34.
Of these, the indicator lamps 33 and 34 can be turned on in conjunction with the relay.

FIG. 3 is a relay sequence diagram for controlling the operation of the solenoid valve 15, in which a plurality of power terminals 35, 36, 3 are connected to control buses R and T to which AC voltage is applied.
7, 38, and 39 are connected in parallel, among which the flow switch 29 and the first relay R1 are inserted into the power terminal 35, and the first relay _R1 is inserted into the power terminal 36.
A contact _R11 of _R1 , a normally closed contact S _T2 of a second timer, and a second relay _R2, which will be described later, are inserted.

A contact R ₂₁ of a second relay R ₂ is connected in parallel to the contact R ₁₁ , and a first timer T ₁ of a time-limited operation type is connected in parallel to _{the second relay R 2 .} turns on the contact described later after the set time t ₁
I try to let them do it. A contact R ₁₂ of the first relay R ₁ and a second timer T ₂ of a time-limited operation type are inserted into the power supply terminal 37, and this timer T ₂ operates, that is, turns off the contact S _T2 after a set time t ₂ . That's what I do.

Further, the power terminal 38 includes a contact S _T1 of the first timer T ₁ and a normally closed contact of the first relay R _1.
R13 and a third relay _R3 are inserted, and in the case of the embodiment, this third relay _R3 drives the ratchet mechanism to turn the contacts ON and OFF when voltage is applied and released.
An operable ratchet relay is used.
Further, the contact R ₃₁ of the third relay R ₃ and the solenoid valve 15 are inserted into the power terminal 39,
A fourth relay _R4 that can control the operation of the indicator lamps 33 and 34 is connected in parallel to the valve 15, and the contact of the cold water indicator lamp 33 is normally turned on.
However, when the fourth relay _R4 is energized, that is, when the solenoid valve 15 is activated, the contacts of the hot water indicator lamp 34 are turned ON, and the contacts of the cold water indicator lamp 33 are turned OFF instead.

In addition, 40 in the figure is a power supply terminal 39 between the contact R ₃₁ and the solenoid valve 15, and an auxiliary lead wire whose both ends are connected to the control bus R. A main drive changeover switch 41 is inserted into this wire 40, and the third relay Separately from the operation of _R3 , the solenoid valve 15 is turned on as appropriate to enable hot water to be supplied to the stop gun 24.

(Function) Before using the cold/hot water switching device configured as described above, the water supply valve (not shown) is opened and the cold water 18
is introduced into a water supply pipe 2 and housed in a float tank 1. When the liquid level in the float tank 1 reaches a predetermined level as the cold water 18 is supplied, the float 3
The float valve 4 linked to the displacement of is closed,
The water supply from the water supply pipe 2 is cut off. Then, when the liquid level in the float tank 1 decreases as the cold water 18 is supplied to the boiler 6 or the directional control valve 10, the float valve 4 opens in conjunction with the displacement of the float 3, and the water supply pipe 2 The liquid level in the tank 1 is restored to a predetermined level by prompting water supply from the tank 1.

The cold water 18 thus accommodated in the float tank 1 is guided to the boiler 6 by opening the water valves (not shown) installed in the connecting pipe 5 and the cold water pipe 9. to the water space or directional control valve 10 inside. Under these circumstances, when the burner 7 is ignited and the cold water contained in the water space is heated, the temperature of the water is detected by a temperature sensor (not shown), and a signal is sent to the burner 7 when a predetermined temperature is reached. Then, heating of the burner 7 is stopped and hot water at a predetermined temperature is generated.

Also, around the time when water supply to the float tank 1 starts, an air supply valve (not shown) installed in the pneumatic pipe 16 is opened, and pressurized air is guided to the pneumatic pipe 16 and can be supplied to the solenoid valve 15. Become. The solenoid valve 15 normally communicates with the pneumatic pipe 16 and the air supply pipe 14b, and reduces the piston rod 13 as shown in the first figure.
In preparation for the automatic switching operation of 5, the manual changeover switch 4
Turn 1 off.

After completing a series of preparatory operations, when it comes time to actually wash the underside of a large vehicle such as the body or frame of a large vehicle that has entered the car wash, the underside usually has dirt and sand attached to it, but relatively little oil or grease. A cold water wash is performed.

Therefore, when performing this cold water washing, first, the switch 32 of the water supply pump 21 is turned on, and the drive motor 20 is started, and the water supply pump 21 directly connected thereto is started. On the other hand, the directional control valve 10
is normally placed in the state as _shown in _FIG . The suction pipe 19 communicates with the hot water port
_P2 is blocked, and communication between the hot water pipe 8 and the suction pipe 19 is cut off.

Therefore, with the start of the water supply pump 21, the cold water 18 in the cold water pipe 9 is guided from the cold water port _P1 to the rotary valve 10a through the guide hole 42, and the common port
It flows out from P ₃ to the suction pipe 19, is sucked into the water supply pump 21, and is discharged to the discharge pipe 22. The cold water sent out to the discharge pipe 22 is guided to the stop gun 24 via the water supply hose 23, and can be sprayed from the nozzle 26 through the operation of the trigger 25. Therefore, by pulling the trigger 25, cleaning with high-pressure cold water jetted from the nozzle 26 becomes possible, and the cold water required for cleaning moves from the float tank 1 at high speed through the aforementioned flow path to the stop gun. 24.

In this case, a part of the cold water discharged from the water supply pump 21 to the discharge pipe 22 is guided to the bypass pipe 27, passes through the relief valve 28 and the flow switch 29, and is returned to the water space of the boiler 6. Under the condition where cleaning water is being injected from the bypass pipe 27, the flow rate of the cold water flowing through the bypass pipe 27 cannot reach a predetermined amount, so the flow switch 29 does not operate. Therefore, cold water will be spouted from the stop gun 24 all the time.

On the other hand, when cleaning the engine and areas around the front and rear axles at the same time as underbody cleaning, these areas are usually covered with oil and grease and cannot be adequately cleaned with cold water, so cleaning with hot water is not recommended. It is done.

Therefore, when performing hot water cleaning, the trigger 25 may be released while holding the stop gun 24 to temporarily stop the injection of cold water, and then the trigger 25 may be immediately pulled to perform the opening operation.

That is, when the trigger 25 of the stop gun 24 is released to close it, the injection of cold water from the nozzle 26 is stopped, and at the same time, the movement of the cold water in the discharge pipe 22 and the water supply hose 23 is stopped, so that they remain. Even in such a case, the water supply pump 21 and its driving motor 20 continue to drive to forcefully deliver cold water to the discharge pipe 22, so that the entire amount of the supplied water flows into the bypass pipe 27 and is guided to the relief valve 28. After being pressure regulated by the valve 28, it flows into the flow switch 29.

The flow switch 29 has a movable piece with one end installed in the bypass pipe 27, and the movable piece is displaced in accordance with the flow rate or dynamic pressure of cold and hot water, thereby making it possible to detect a predetermined flow rate of cold and hot water. The actuating piece connected to the micro switch operates in conjunction with a predetermined displacement of the movable piece, thereby turning on the micro switch. Even after the flow switch 29 is closed, it remains in the ON state while a large amount of cold water flows through the bypass pipe 27, and as a result, the first relay _R1 inserted into the power supply terminal 35 that constitutes the relay sequence is energized, and the contact
R ₁₁ and R ₁₂ turn on, and contact R ₁₃ turns off.

Therefore, the power terminals 36 and 37 are closed, and the power terminal 38 is opened. Of these, when the terminal 36 is closed, the second relay R ₂ is energized, its contact R ₂₁ is turned ON, and the second relay R 2 is energized.
The first timer T ₁ connected in parallel to relay R ₂ is ON
Then, the time-limited operation of the contact _ST1 is started, and when the terminal 37 is closed, the second timer _T2 is turned on, and the time-limited operation of the contact _ST2 is started.

Setting times t 1 and t _{2 are set for these first and second timers T 1 and T 2 , and in} the embodiment, t ₁ =0.5sec,
t ₂ =1 sec, and these contacts S _T1 and S _T2 are turned ON and OFF after the set times t ₁ and t ₂ have elapsed. Therefore, if t ₁ <
In the case of t ₂ , if the trigger 25 of the stop gun 24 is pulled and opened before the set time t ₁ elapses, the residual cold water will be injected from the nozzle 26, and the cold water discharged from the water supply pump 21 will be discharged. The flow rate from the pipe 22 to the bypass pipe 27, which has a large flow resistance and is led to the water supply hose 23, returns to a steady small amount state, and the flow switch 29 is turned off.

As a result, the power terminal 35 is opened and the terminal 3
The first relay R ₁ inserted in the relay 5 is demagnetized and its contacts R ₁₁ and R ₁₂ are turned OFF, while the contact R ₁₃
is turned on. Therefore, the power supply terminal 37 is opened, the time-limited operation of the second timer _T2 is canceled, and the ON state of the contact S _T2 is maintained, and the power is supplied via the self-holding contact R ₂₁ and the contact S _T2 , second
The ON state of relay R ₂ and first timer T ₁ continues.

However, before the set time t ₁ elapses, contact S _T1
is in the OFF state, so even if contact R ₁₃ is ON as described above, the power terminal 38 is open.
In the end, since the current state of the third relay _R3 , that is, the OFF state, is maintained, its contact _R31 also maintains the current OFF state. Therefore, since the power terminal 39 remains open, the solenoid valve 15 connected to the terminal 39 cannot operate. That is,
In this case, as shown in FIG. 4a, cold water is sprayed from the stop gun 24 and the water is not switched to hot water.

Even in this case, there is no practical problem as long as the set time t ₁ is set to the minimum necessary value in relation to the response speed of the flow switch 29 and the operating speed of the third relay R ₃ . Since there is a limit to the operating speed, the use in the above conditions is actually rare and there is no problem.

Next, after the stop gun 24 stops injecting, when the set time t ₁ (t ₁ < t < t ₂ ) has elapsed, the contact S _T1 is turned on.
do. When the trigger 25 is pulled and the stop gun 24 is opened under such a situation, the residual cold water is injected from the stop gun 24 as described above, and the cold water discharged from the water supply pump 21 is transferred from the discharge pipe 22 to the water supply hose. 23, bypass pipe 2
Since only a small amount of cold water flows into 7,
Flow switch 29 is turned off.

As a result, the power terminal 35 is opened and the terminal 3
The first relay R ₁ inserted in the relay 5 is demagnetized and its contacts R ₁₁ and R ₁₂ are turned OFF, while the contact R ₁₃
is turned on. Therefore, the power supply terminal 37 is opened, the time-limited operation of the second timer _T2 is canceled, and the ON state of the contact S _T2 is maintained, and the power is supplied via the self-holding contact R ₂₁ and the contact S _T2 , second
The ON state of relay R ₂ and first timer T ₁ continues.

Therefore, the power supply terminal 38 is closed, and the third relay _R3 connected to the terminal 38 is activated to drive the ratchet mechanism, turning the contact _R31 ON in the opposite direction from the current state. Therefore, the power terminal 39 is closed, and the solenoid valve 15 connected to the terminal 39 is switched.

That is, the communication between the pneumatic pipe 16 and the air supply pipe 14b is cut off, and instead, the pneumatic pipe 16 and the air supply pipe 14a are electrically connected, and pressurized air is guided into the cylinder 12 via the air supply pipe 14a. As a result, piston 1
The piston rod 13 extends in conjunction with the displacement of the piston rod 13, and the connecting rod 11 connected to the tip of the rod 13 moves to the imaginary line position shown in the first figure, and the rotary valve 10a integrated with the rod 11 rotates synchronously. move.

That is, the rotary valve 10a is switched from the state shown in FIG. _2a to the state shown in _FIG . The hot water pipe 8 and the suction pipe 19 communicate with each other, while the cold water port
_P1 is blocked, and the communication between the cold water pipe 9 and the suction pipe 19 is cut off.

Therefore, the hot water generated in the water space of the boiler 6 is transferred from the hot water pipe 8 to the hot water port _P2.
is led into the rotary valve 10a through the common port
After flowing out from P ₃ into the suction pipe 19, it is sucked into the water supply pump 21, and is discharged from the pump 21 into the discharge pipe 22, and then through the water supply hose 23 to the stop gun 24.
guided by.

That is, in this case, hot water is injected from the stop gun 24, and the injection mode is switched from cold water to hot water as shown in FIG. 4b. In this way, according to the present invention, the hot water can be switched instantaneously and easily by operating the trigger 25 of the stop gun 24, which improves the convenience of use and makes it possible to perform this type of cleaning work efficiently. Alternatively, you can freely and quickly set up hot water cleaning, so you can choose the most suitable cleaning method depending on the area to be cleaned and the level of dirt.
Moreover, since these cleaning methods can be selected rationally,
For example, fuel consumption can be reduced compared to cleaning with only hot water.

On the other hand, when the set time _t2 has elapsed after the stop gun 24 stops injecting, in addition to the above-described ON operation of the contact _ST1 , the contact _ST2 is turned OFF. Therefore,
The power supply terminal 36 is opened, the second relay _R2 is demagnetized, the first timer _T1 is turned off, and both the contacts _R21 and S _T1 are turned off. As a result, the power terminal 38 is opened, the third relay _R3 is placed in the current OFF state, and the current state of the contact _R31 , that is, the OFF state is maintained, so the power terminal 39 is maintained in the open state.

Under these circumstances, when the trigger 25 is pulled and the stop gun 24 is opened, the flow switch 29 is turned OFF as described above, and the first relay is turned off.
R ₁ is demagnetized and contacts R ₁₁ and R ₁₂ are turned OFF,
Contact _R13 is turned ON. Therefore, power terminal 3
In addition to terminals 6, 38, and 39, the power terminal 37 is also opened, and the solenoid valve 15 is in the OFF state and cannot operate, so in this case, cold water is again injected from the stop gun 24 as shown in Figure 4c. and does not switch to hot water.

In this way, the time from once stopping the injection of the stop gun 24 to restarting the injection is normally continuous without interruption, except when the cleaning operation is _temporarily interrupted. The maximum grace period required is set as a guideline, and the necessity of switching the hot water is determined based on this time, and the actual cleaning work is coded.

Moreover, in this case, if the cold water injection mode is uniformly set after the set time t ₂ has elapsed as in the embodiment, the consumption of hot water can be prevented and fuel can be saved. .

Note that even when hot water is being injected as shown in FIG. 4b, if the injection is restarted between the set time t ₁ and _{t 2} after the injection is stopped, it is possible to switch from hot water to cold water, and the set time t ₂ can also be switched from hot water to cold water. If the injection is resumed after the elapsed time, hot water will be injected again without switching to cold water.
Further, in this embodiment, the operation of the solenoid valve 15 is controlled by the relay sequence shown in FIG. 3, but these sequence circuits are omitted,
If the operation of the solenoid valve 15 is directly controlled ON/OFF by the operation of the flow switch 29, a hot water switching device with a simple configuration and low cost can be provided.

(Effects of the Invention) As described above, the cold/hot water switching device of the present invention includes a directional control valve that communicates with a cold water source and a hot water source and can selectively switch between the cold and hot water, and a pipe on the outlet side of the valve. a control switch installed in a bypass pipe communicating with the pipe, which detects a predetermined momentum of cold and hot water moving in the pipe and outputs a signal; and a drive capable of switching the directional control valve in conjunction with the signal from the switch. Since the system is provided, it is possible to automatically and instantaneously switch between cold and hot water when a predetermined momentum of the cold and hot water in the bypass pipe is formed, such as flow rate, dynamic pressure, or flow velocity.

This effect is particularly suitable for car washing work, which requires the use of hot and cold water at different times depending on the washing capacity, and has the advantage of allowing optimal and rational washing to be carried out depending on the location to be washed and the level of dirt.

Further, the cold/hot water switching device of the present invention is installed in a directional control valve that communicates with a cold water source and a hot water source and can selectively switch between the cold and hot water, and a bypass pipe that communicates with an outlet side pipe of the valve. It is equipped with a control switch that detects a predetermined momentum of cold and hot water moving in the pipe and outputs a signal, and if the time required for the switch to turn on and off is within a predetermined time, the cold and hot water can be switched. Therefore, when the flow rate of cold and hot water in the bypass pipe changes, for example when starting to use cold and hot water, the cold and hot water can be switched and used.
If you set the above predetermined time according to the actual situation of use,
Cold and hot water can be used depending on the actual usage conditions.

Furthermore, the cold/hot water switching device of the present invention is installed in a directional control valve that communicates with a cold water source and a hot water source and can selectively switch between the cold and hot water, and a bypass pipe that communicates with an outlet side pipe of the valve. The system is equipped with a control switch that detects a predetermined amount of motion of cold and hot water moving in the pipe and outputs a signal, and if the time required for the ON/OFF operation of the switch is longer than the predetermined time, the cold and hot water cannot be switched. Since this is made possible and the original water supply mode is maintained, there is an effect that the original hot water or cold water can be continued to be used after the set time has elapsed.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing one embodiment of the present invention, with a part shown in cross section, and FIG. 2 is a cross sectional view showing the operating state of the directional control valve used in the present invention.
3 shows a cold water supply state, FIG. 3b shows a hot water supply state, FIG. 3 is a sequence diagram showing an example of the control circuit used in the present invention, and FIGS. This is a time chart showing the operating status. 10... Directional control valve, 27... Bypass pipe, 2
9...Control switch.

Claims (1)

[Scope of Claims] 1. A directional control valve that communicates with a cold water source and a hot water source and is capable of selectively switching between the cold and hot water; A control switch that detects a predetermined momentum of cold and hot water moving through the water and outputs a signal, and a drive system that can switch the directional control valve in conjunction with the signal from the switch. Switching device. 2. A directional control valve that communicates with a cold water source and a hot water source and can selectively switch between these cold and hot water sources, and a directional control valve that is installed in a bypass pipe that communicates with the outlet side pipe of the valve and that controls the cold and hot water that moves within the pipe. Equipped with a control switch that detects a predetermined amount of motion and outputs a signal,
A cold/hot water switching device characterized by being capable of switching between cold and hot water if the time required for ON/OFF operation is within a predetermined time. 3 A directional control valve that communicates with a cold water source and a hot water source and can selectively switch between these cold and hot water sources, and a directional control valve that is installed in a bypass pipe that communicates with the outlet side pipe of the valve and that controls the cold and hot water that moves within the pipe. Equipped with a control switch that detects a predetermined amount of motion and outputs a signal,
A cold/hot water switching device characterized in that when the time required for ON/OFF operation is longer than a predetermined time, switching between cold and hot water becomes impossible and the original water supply mode is maintained.