JPH0635998Y2 - Liquid supply device for delivery truck - Google Patents

Description

[Detailed Description of the Invention] [Industrial application] The present invention relates to a liquid supply device for discharging a liquid in a tank from a nozzle in a delivery truck, more specifically, a return pipe before closing the nozzle at the end of liquid supply. Open to reduce the pump discharge pressure to reduce the amount of liquid trapped between the pump and the nozzle.Also, even though the tank is empty, the liquid supply operation is continued and air is discharged from the nozzle. The present invention relates to a liquid supply device for a delivery truck that can prevent the above.

[Conventional technology]

In the delivery truck, the liquid in the tank is supplied from a nozzle to a predetermined oil tank or the like.

In the conventional liquid supply device for delivery truck, the discharge pipe is connected to the bottom of the tank, and the liquid in the tank is guided to the nozzle through the discharge pipe and the hose. A check valve is provided in the nozzle. Further, the relief valve is built in the pump, and when the nozzle is closed and the discharge pressure of the pump exceeds a predetermined value, the relief valve is opened and the discharge pressure of the pump is lowered.

When supplying liquid such as oil from the nozzle to the oil tank or the like, the pump is driven to pump the liquid from the tank to the nozzle, and the nozzle is inserted into the oil supply port of the oil tank to open the nozzle. . In this case, in order to avoid that the inside of the tank becomes empty and air is ejected from the nozzle, the operator judges that the inside of the tank is approaching and closes the nozzle. After the liquid supply is completed, the hose is wound on the hose reel in order to store the hose.

[Problems to be solved by the device]

With the conventional liquid supply device for delivery trucks, the fact that the inside of the tank is nearly empty is left to the operator to consider, so the nozzle is kept closed even after the tank is emptied. As a result, air is likely to be ejected from the nozzle.

Also, when the hose is wound on the hose reel after the liquid supply is completed, the internal pressure of the hose is the relief set pressure of the relief valve, and it is still high pressure.If the check valve is not completely sealed, the liquid will flow backward. There is a risk of

An object of a first aspect of the present invention is to provide a liquid supply device for a delivery truck that can prevent the discharge of air from the nozzle even if the closing of the nozzle is delayed.

The object of claim 2 is that the inside of the tank approaches the sky,
It is an object of the present invention to provide a liquid supply device for a delivery truck that can promptly inform an operator of the possibility that air will be ejected from a nozzle.

A third object of the present invention is to provide a liquid supply device for a delivery truck that can lower the internal pressure of the hose when the worker closes the nozzle.

[Means for Solving the Problems]

In the liquid supply device for delivery truck according to claim 1, a discharge pipe connected to the bottom of the tank, a pump provided in the discharge pipe for pumping liquid from the tank to the nozzle, and a liquid in the tank having a predetermined amount or less. The liquid detector that detects the fact that the liquid is in the tank is below a predetermined amount by controlling the opening and closing of the return passage that connects the suction side and the discharge side of the pump. An open / close valve that opens the return passage when detected, and an open / close valve that has a valve opening pressure higher than the pump discharge pressure when the open / close valve is in the open state and the pump is discharging air are provided between the nozzle and the pump. And a check valve that allows the flow of liquid from the pump side to the nozzle side.

The liquid supply device for a delivery truck according to a second aspect of the present invention further includes an operating device carried by an operator. This operating device is provided with an alarm means for informing the operator that the liquid detector detects that the amount of liquid in the tank has dropped below a predetermined amount.

In the liquid supply device for a delivery truck according to a third aspect of the present invention, the operating device includes a remote operation switch which is operated by an operator and forcibly opens the opening / closing valve by remote control.

The delivery lory liquid supply device according to claims 4 and 5 further comprises a relief valve that connects the discharge side of the pump to the suction side when the discharge pressure of the pump exceeds a certain value, and the on-off valve is the relief valve. It is provided separately from the valve, or the relief valve is also used as the opening / closing valve.

[Action]

According to the first aspect of the invention, the on-off valve closes the return passage when the liquid is sufficiently present in the tank. Therefore, the liquid in the tank is sucked by the pump, is pressure-fed toward the nozzle through the discharge pipe, and is discharged from the nozzle.

When the inside of the tank approaches or becomes empty, the liquid detector detects this and the on-off valve opens the return passage. When the pump is pumping air, the air on the discharge side of the pump is returned to the suction side of the pump via the return passage. Since the flow resistance of air is small, even if the diameter of the return passage is small, the air smoothly flows through the return passage from the discharge side of the pump to the suction side, the discharge pressure of the pump is sufficiently reduced, and the check valve is opened. Lower than pressure. Therefore, the check valve is closed,
Delivery of air from the pump to the nozzle is blocked and there is no discharge of air from the nozzle.

According to the second aspect of the invention, when the tank approaches the empty state, the alarm signal of the operating device is activated by the detection signal of the liquid detector, and the operator is informed that the tank is near the empty state.

According to the third aspect of the invention, the operator operates the remote control switch of the operating device just before finishing the liquid supply work from the nozzle. As a result, the on-off valve is opened and the discharge pressure of the pump is reduced. Then, if the nozzle is closed, the hydraulic pressure contained between the pump and the nozzle can be reduced.

According to the fourth aspect of the invention, the discharge side of the pump communicates with the suction side by the opening / closing valve separate from the relief valve.

According to the invention of claim 5, the relief valve is opened based on the detection signal of the liquid detector and the remote operation from the remote operation switch of the operation device, and the discharge side of the pump communicates with the suction side.

〔Example〕

 The present invention will be described below with reference to the embodiments shown in the drawings.

The drawing is a block diagram of a liquid supply device for a delivery truck as an embodiment of the present invention. The delivery truck 10 includes a tank 12 behind a cab (not shown), and a liquid 14 is stored in the tank 12. The discharge pipe 16 has its upstream end connected to the bottom of the tank 12, and the discharge pipe 16 includes a pump 18 from the tank 12 side,
A flow meter 20 and a check valve 22 are provided. Relief valve 24
Is incorporated in the pump 18, and when the nozzle 32 described later is closed and the discharge pressure of the pump 18 exceeds a certain value, the pump is opened and the discharge pressure of the pump 18 is relieved. Check valve 22
Ball 26 that can receive and displace hydraulic pressure on the flowmeter 20 side
And a compression coil spring 28 that urges the ball 26 toward the flowmeter 20 to bring it into a closed state. The hose 30 is equipped with a nozzle 32 that can be opened and closed manually by an operator,
Wound on a rotatable hose reel 34 or hose reel
It is fed from 34 and is connected to the downstream end of the discharge pipe 16. The return pipe 36 as a return passage is connected to the pump 18 at both ends at the discharge side and the suction side of the discharge pipe 16, and a solenoid valve type return valve 38 is provided in the return pipe 36.
Open and close the return pipe 36. The liquid detector 40 is provided at the bottom of the tank 12 and detects the presence or absence of the liquid 14 therein. The controller 42 includes a liquid detector 40 and a return valve 38 via electric wires 44 and 46.
The control signal is sent to the return valve 38 and the detection signal of the liquid detector 40 is input. The operation device 48 is portable by an operator, is connected to the control device 42 via an electric wire 50, and includes an alarm device 52 and an operation switch 54.
The operation device 48 may be of a type that transmits / receives a signal to / from the controller 42 by a radio signal, an ultrasonic signal, an infrared ray, or the like, instead of an electric signal via the electric wire 50.

The operation of the embodiment will be described.

The liquid detector 40 detects the presence or absence of the liquid 14 at the bottom of the tank 12, and this detection signal is input to the controller 42 via the electric wire 44.

When sufficient liquid 14 is present in tank 12, return valve
Reference numeral 38 closes the return pipe 36 according to the control signal from the controller 42. Therefore, the liquid 14 in the tank 12 is
Is sucked by, is pressure-fed to the nozzle 32 through the discharge pipe 16 and the hose 30, and is discharged from the nozzle 32.

When the tank 12 approaches or becomes empty, the liquid detector 40 detects this, and the return valve 38 opens the return pipe 36 by a control signal from the controller 42. When the pump 18 is pumping air, the air on the discharge side of the pump 18
It is returned to the suction side of the pump 18 via 36. Since air has a small flow resistance, even if the diameter of the return pipe 36 is smaller than that of the discharge pipe 16, the return pipe 36 smoothly flows from the discharge side of the pump 18 to the suction side, and the discharge pressure of the pump 18 is: The pressure is sufficiently reduced, and is reduced by the biasing force of the compression coil spring 28 of the check valve 22, that is, the valve opening pressure of the ball 26. Therefore, the check valve 22 is closed, the air supply from the pump 18 to the hose 30 is blocked, and the air is not discharged from the nozzle 32.

Further, when the liquid detector 40 detects that the tank 12 is nearly empty, and the detection signal is input to the controller 42, the controller 42 sends a control signal to the operation device 48 at the same time as the return valve 38. Send this result. The alarm 52 of the operation device 48 is activated, and the operator is informed that the tank 12 is almost empty by an alarm sound and / or a display. As a result, the operator promptly closes the nozzle 32 and stops the liquid supply from the nozzle 32.

When the liquid supply work from the nozzle 32 approaches the end without the tank 12 becoming empty, the operator operates the operation switch 54 of the operation device 48. As a result, the return valve 38 receives the control signal from the controller 42, opens the return pipe 36, and the liquid 14 on the discharge side of the pump 18 is returned to the suction side of the pump 18 via the return pipe 36. Therefore, the discharge pressure of the pump 18 decreases, and at the same time, the discharge amount also decreases. Then, when the predetermined amount of refueling is reached, the nozzle 32 is closed. After this, the worker
The hose 30 is wound on the hose reel 34, but the internal pressure of the hose 30 is sufficiently lower than the relief pressure of the relief valve 24.
Backflow from the hose 30 side to the relief valve 24 side is prevented.

In the illustrated embodiment, the return pipe 36 and the return valve 38 are provided separately from the relief valve 24, but the relief valve 24 has a return passage that connects the discharge side of the pump 18 to the suction side. Using this, the relief valve 24 is forcibly opened by the control signal from the controller 42, and the return pipe 36
By omitting the return valve 38, the device can be simplified.

[Effect of device]

According to the first aspect of the invention, when the pump is pumping air toward the nozzle, the on-off valve opens the return passage to return the air on the discharge side of the pump to the suction side, and the air pressure on the discharge side of the pump is Since the pressure drops below the valve opening pressure of the check valve, the check valve is closed. Therefore, air is not pressure-fed to the nozzle, and air is prevented from being ejected from the nozzle.

According to the second aspect of the present invention, when the operator is carried by the operator and the tank approaches the empty state, the alarm means of the operator notifies the operator by means of a display and sound, so that the operator quickly closes the nozzle. can do.

According to the third aspect of the present invention, when the liquid supply from the nozzle approaches the end, the remote control switch of the operating device is operated and the discharge side of the pump communicates with the suction side by the open / close valve, so the nozzle is closed. . Therefore, the discharge pressure of the pump is sufficiently reduced to less than the relief pressure of the relief valve, the inside of the hose is lowered, and the backflow in the check valve during the hose winding operation can be prevented.

In the device of the fifth aspect, the relief valve normally equipped in the pump can be used as the return passage and the opening / closing valve, so that the device can be simplified.

BRIEF DESCRIPTION OF THE DRAWINGS The drawings are block diagrams of a delivery truck liquid supply device as an embodiment of the present invention. 10 …… Delivery truck, 12 …… Tank, 16 …… Discharge pipe, 18
...... Pump, 22 …… Check valve, 32 …… Nozzle, 36 …… Return piping (return passage), 38 …… Return valve (open / close valve), 40 …… Liquid detector, 48 …… Operator, 52 ... Alarm device (alarm means), 54
...... Operation switch (remote operation switch).

Claims (5)

[Scope of utility model registration request] 1. A discharge pipe connected to the bottom of a tank, a pump provided in the discharge pipe for pumping a liquid from the tank to a nozzle, and detecting that the liquid in the tank is below a predetermined amount. A liquid detector, a return passage communicating between the suction side and the discharge side of the pump, and opening / closing of the return passage are controlled by the liquid detector to detect that the amount of liquid in the tank has dropped below a predetermined amount. And an opening / closing valve that opens the return passage, and a valve opening pressure that is greater than the pump discharge pressure when the opening / closing valve is in the open state and the pump is discharging air, and between the nozzle and the pump. And a check valve which is provided in the pump and allows the flow of liquid from the pump side to the nozzle side. 2. An operating device carried by an operator, the operating device confirming that the liquid detector detects that the amount of liquid in the tank has dropped below a predetermined amount. 2. The liquid supply device for a delivery truck according to claim 1, further comprising alarm means for notifying an operator. 3. The operating device comprises a remote operation switch operated by an operator and forcibly opening the open / close valve by remote control.
Liquid delivery device for the delivery truck described. 4. A relief valve for connecting the discharge side of the pump to the suction side when the discharge pressure of the pump exceeds a certain value, and the opening / closing valve is provided separately from the relief valve. The liquid supply device for a delivery truck according to any one of claims 1 to 3, wherein 5. A relief valve is provided which connects the discharge side of the pump to the suction side when the discharge pressure of the pump exceeds a certain value, and the relief valve also serves as the opening / closing valve. The liquid supply device for a delivery truck according to any one of claims 1 to 3.