JPH0759440B2 - Fuel tank drainer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a fuel tank drainer for pumping and discharging water accumulated in a fuel tank.

[Prior Art] Conventionally, as a device for draining water accumulated in a fuel tank, for example, one disclosed in Japanese Utility Model Laid-Open No. 53-130316 is known. This is because an indicator ball that closes the drain pipe when descending, and has a specific gravity heavier than fuel and lighter than water is vertically inserted over a predetermined height, and the drain pipe and drain drain from the bottom of the fuel tank. It drains through a cock. Further, as disclosed in Japanese Utility Model Laid-Open No. 61-128133, a water sensor for detecting the water level is provided, and the discharge device is operated based on a change in resistance detected by the water sensor, and the water sensor is provided at the bottom of the fuel tank. It is also known to discharge water through a solenoid valve.

[Problems to be Solved by the Invention] However, dust, rust, and the like tend to accumulate on the bottom of the fuel tank,
These are mixed with the water that has accumulated at the bottom. For that reason,
If this water is discharged from the drain pipe, drain cock, solenoid valve, etc. installed at the bottom of the fuel tank, dust and rust will enter between the indicator ball and the drain pipe, making it impossible to completely block the drain pipe. Or, the solenoid valve may not close completely and some of the fuel may leak out. In addition, dust and rust adhere to the flow path, narrowing the flow path,
There was a risk that the drainage function would deteriorate.

Furthermore, when drainage is controlled by opening and closing the solenoid valve, the water sensor detects that water has accumulated and opens the solenoid valve, then closes the solenoid valve too early. Cannot be drained. On the other hand, if the timing of closing the solenoid valve is too late, not only water but also a part of the fuel will be discharged, leading to a waste of fuel and a risk of fire.

Therefore, the present invention aims to solve the above problems,
It is an object of the present invention to provide a drainage device for a fuel tank, which can prevent the drainage function from being deteriorated due to dust or rust on the bottom of the fuel tank and can properly drain the water accumulated at the bottom of the fuel tank.

[Means for Solving the Problems] In order to achieve the above object, the present invention has the following configurations as means for solving the problems. That is, a water level detection sensor for detecting that the water level of the water accumulated at the bottom of the fuel tank for storing fuel reaches a predetermined level, and when the water level detection sensor detects that water has accumulated, the fuel A pump for pumping through a water conduit extending from the mouth on the upper side of the tank toward the bottom is arranged, and a water sensor for detecting water pumped through the water conduit is provided. When detected, a drainage mechanism that switches from a return position that communicates the return hole opened in the fuel tank and the water conduit to a drainage position that communicates the drain hole that communicates with the outside of the fuel tank and the water conduit. This is the structure of the water draining device for the fuel tank, which is characterized in that

[Operation] In the fuel tank water draining device having the above configuration,
The water level detection sensor detects that the water level of the water accumulated at the bottom of the fuel tank reaches a predetermined water level, and the pump pumps the water from the bottom of the fuel tank to the upper port of the fuel tank via the water conduit. Then, the water sensor detects the water pumped through the water conduit, and when the water is detected, the drainage mechanism causes the return hole opened in the fuel tank to communicate with the water conduit from the return position. , The drainage position is switched to the drainage hole communicating with the outside of the fuel tank and the water conduit.

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

FIG. 1 is a cross-sectional view of a fuel tank water draining device according to an embodiment of the present invention. Reference numeral 1 denotes a fuel tank for storing kerosene or the like as fuel, and in this embodiment, it has a rectangular parallelepiped shape. On the upper side of the fuel tank 1, there is provided a cylindrically formed supply port 2 into which fuel can be injected, and a main body 4 detachably fitted to the supply port 2 is provided.
It is attached so as to close the supply port 2. The main body 4 is composed of two layers, that is, a metal lower body 4a fitted into the supply port 2 and an electrically insulating upper body 4b laminated thereon. A fitting hole 6 opening toward the inside of the fuel tank 1 is formed in the lower portion 4a of the main body, and one end of a straight metal-made pumping pipe 8 is fitted into the fitting hole 6. Has been done.

The pumping pipe 8 is connected to the bottom of the fuel tank 1 from the supply port 2.
It extends toward 1a, and a suction member 10 is electrically insulated and attached to a tip 8a thereof. The suction member 10 is provided with a suction port 12 opening toward the bottom 1a of the fuel tank 1 on an extension line of the pumping pipe 8, and the inside of the suction port 12 is made hollow to pump up with the suction port 12. It communicates with the pipe 8.

Then, the metal pump shaft 14 that penetrates the inside of the upper body 4b, the fitting hole 6, and the pumping pipe 8 in the axial direction and reaches the inside of the suction member 10 at its tip is electrically connected to the lower body 4a of the body. It is rotatably supported on the upper part 4b of the main body while being insulated. A fin 16 is attached to the tip of the pump shaft 14, and a rotating shaft of a motor 20 is connected to the other end of the pump shaft 14 via a coupling 18. By rotating the motor 20, the pump shaft 14 and the fins 16 are rotated, sucked from the suction port 12 and discharged into the pumping pipe 8.
22 are formed.

In addition, on the upper part 4b of the main body around the pump shaft 14, brush guide
24 is provided, and the electrode brush is attached to this brush guide 24.
Pump shaft with electrode brush 26 attached and rotating with electrode brush 26
An electrical connection is established between 14 and. The pumping pipe 8, the pump shaft 14, and the electrode brush 26 form a water level detection sensor 27.

On the other hand, the fitting hole 6 extends from the lower body 4a to the upper body 4b.
A communication hole 28 communicating with the pumping pipe 8 via the through hole is formed, and a water conduit 25 is formed by the fitting hole 6, the pumping pipe 8, and the communication hole 28. Further, a return hole 30 that communicates with the communication hole 28 via the first valve seat 29 and opens toward the inside of the fuel tank 1 is formed. Further, the second valve seat is provided in the communication hole 28.
A drainage hole 32 communicating with the fuel tank 31 and opening to the outside of the fuel tank 1 is formed. The valve seats 29 and 31 are formed to face each other, and the valve element 34 slidably supported by the upper portion 4b of the main body is provided on the valve seats 29 and 31 so as to be seated thereon. An armature 36 is connected to the valve body 34, and the armature 36 is moved by an urging force of a spring 38 and an electromagnetic force of a coil 40. Then, by the urging force of the spring 38, the valve body 34 is returned to the return position where it is seated on the second valve seat 31, and the electromagnetic force by the excitation of the coil 40 is placed at the drainage position where the valve body 34 is seated on the first valve seat 29. It is configured so that each can be switched. These valve seats 29, 31, valve element 34, armature 36, spring 38, and coil 40 form an electromagnetic switching valve 42.

Further, an electrode 44, which penetrates the upper part 4b of the main body and has its tip exposed in the communication hole 28, is attached so as to face the lower part 4a of the main body. This electrode 44, the water sensor 45 by the lower part 4a of the main body
Are formed. The electrode 44, the motor 20, the electrode brush 26, the coil 40, etc. are connected to a circuit board 48 attached to the upper portion 4b of the main body. A cover 46 is attached to the upper portion 4b of the main body so as to cover them.

An electronic control circuit 50 is formed on the circuit board 48, and the electronic control circuit 50 includes a stabilized power supply circuit 52 connected to an external power supply 51, as shown in FIG. Connected to the circuit. Then, the electrode brush 26,
It is connected to the voltage comparison circuit 54, and the pumping pipe 8 is
It is grounded via the lower part 4a of the main body. Voltage comparison circuit 54
Is configured so that its output voltage changes from low level to high level when the resistance value decreases as the resistance value between the pumping pipe 8 and the pump shaft 14 changes. Then, the output voltage is input to the differentiating circuit 56,
Differentiated by 56, a trigger pulse is output. This trigger pulse is input to the monostable pulse generation circuit 58,
When the trigger pulse is input, the monostable pulse generating circuit 58 outputs a pulse signal having a predetermined time T width.
This predetermined time T is set to be longer than the time required for at least the fuel, water, etc. near the tip 8a of the pumping pipe 8 to reach the electrode 44 when the pump 22 is operated. .

On the other hand, the electrode 44 is connected to the voltage comparison circuit 60, the voltage comparison circuit 60, when the resistance value decreases with the change of the resistance value between the electrode 44 and the main body lower portion 4a installed, The output voltage is configured to change from low level to high level. And this output voltage is the solenoid valve drive circuit
The electromagnetic valve drive circuit 62 is configured to output a signal for exciting the coil 40 of the electromagnetic switching valve 42 in response to the change in the voltage.

Further, the signals from the monostable pulse generation circuit 58 and the voltage comparison circuit 60 are input to the OR circuit 64, and when the signals are input from either the monostable pulse generation circuit 58 or the voltage comparison circuit 60, the pump drive circuit. It is configured to output a signal to 66. When a signal is input, the pump drive circuit 66 outputs a drive signal to the motor 20 to drive the motor 20 to rotate. The electromagnetic switching valve 42 and the electronic control circuit 50 form a drainage mechanism.

Next, the operation of the water draining device for the fuel tank of this embodiment described above will be described.

First, the main body 4 and the like are removed from the supply port 2, and the fuel tank 1
, Fuel such as kerosene is injected from the supply port 2, the fuel is consumed, and new fuel is additionally injected each time it is consumed. Further, the water mixed with the fuel is separated, and the water having a larger specific gravity than the fuel is collected at the bottom 1a of the fuel tank 1, and at the boundary, the fuel layer is in the upper layer and the water layer is in the lower layer. it can. Then, with the consumption of fuel, the amount of water accumulated at the bottom 1a increases, the water level rises, and when the water level reaches the detected water level reaching the tip 8a of the pumping pipe 8, the pumping pipe 8 and the pump shaft The resistance value between 14 and is greatly reduced.

As a result, as shown in FIG. 3, the output voltage from the voltage comparison circuit 54 becomes high level, and the differentiation circuit 56 outputs a trigger pulse. Then, the monostable pulse generating circuit 58 receives the trigger pulse and outputs a pulse having a time T width. This allows the OR circuit 64 to drive the pump drive circuit.
A signal is output to 66, and the pump drive circuit 66 outputs a rotation drive signal to the motor 20.

Therefore, the motor 20 rotates, the coupling 18, the pump shaft
The fin 16 is rotated via 14. By the rotation of the fins 16, the water at the bottom 1a of the fuel tank 1 is pumped up through the suction port 12, the pumping pipe 8, the fitting hole 6, and the communication hole 28.

At this time, even in the pumping pipe 8, fuel exists in the upper layer and water in the lower layer in a separated state, and when the water is pumped up,
First, the fuel rises along the pumping pipe 8. This fuel passes through the pumping pipe 8 and the fitting hole 6 and passes through the communication hole 28.
Even if it enters and is interposed between the electrode 44 and the lower part 4a of the main body, the resistance value therebetween is large. Therefore, the output voltage from the voltage comparison circuit 60 is low level, and the drive signal is not output from the solenoid valve drive circuit 62. Therefore, the valve body 34 of the electromagnetic switching valve 42
Is in a state of being seated on the second valve seat 31 by the urging force of the spring 38, and the communication hole 28 and the return hole 30 are in communication. As a result, the fuel is drawn into the pumping pipe 8, the fitting hole 6,
It is returned from the communication hole 28 through the return hole 30 into the fuel tank 1.

On the other hand, with this pumping, the water level becomes lower than the tip 8a of the pumping pipe 8, and the resistance value between the pumping pipe 8 and the pump shaft 14 increases. However, the monostable pulse generator 58
Since a pulse having a time T width is output from, the operation of the motor 20 is continued at least during this time T.

While this operation is continued, water is pumped through the pumping pipe 8 following the fuel, and the tip of the pumping pipe 8 is
When the water in 8a is supplied to the communication hole 28 through the fitting hole 6 and reaches the electrode 44, the resistance value between the electrode 44 and the lower portion 4a of the main body becomes small. As a result, the output voltage from the voltage comparison circuit 60 becomes high level, and the solenoid valve drive circuit 62
Receives this signal and outputs a drive signal for exciting the coil 40. When the coil 40 is excited, the armature 36 moves against the urging force of the spring 38 to move the valve body 34 to the first position.
Seat on valve seat 29.

Further, before the output from the monostable pulse generation circuit 58 becomes low level, the voltage comparison circuit 60 outputs a high level signal to the OR circuit 64. As a result, the pump drive circuit 66
The drive signal is continuously output from the motor 20 to the motor 20, and the operation of the pump 22 is continued.

In this way, the communication hole 28 and the drain hole 32 are communicated, and the return hole 30
The communication with and is cut off, and the water that has passed through the communication hole 28
It is discharged from the fuel tank 1 through the drain hole 32 to the outside of the fuel tank 1. Then, the water level in the fuel tank 1 drops and the suction port 12
The fuel is sucked from the pump, and the fuel is pumped from the pump pipe 8 after the water. When the fuel is supplied from the pumping pipe 8 through the fitting hole 6 to the communication hole 28 and reaches the electrode 44, the resistance value between the electrode 44 and the lower portion 4a of the main body increases, and the voltage comparison circuit 60 The output voltage from is at low level.

As a result, first, the excitation of the coil 40 by the solenoid valve drive circuit 62 is stopped. Further, since the time T has elapsed during this time, the input signals to the OR circuit 64 from the monostable pulse generation circuit 58 and the voltage comparison circuit 60 both become low level, and the pump drive circuit 66 drives the motor 20. The drive is stopped. Therefore, the electromagnetic switching valve 42 is used to connect the communication hole 28 and the drain hole 32.
The communication with the communication hole 28 and the return hole 30 are communicated with each other. Further, the operation of the pump 22 is stopped and the pumping is completed.

As described above, the drainage device for the fuel tank of this embodiment is
When the water level detection sensor 27 detects that the detected water level has been reached, the pump 22 is operated to pump up from the bottom 1a of the fuel tank 1 through the pumping pipe 8. Then, until the water sensor 45 detects water, the electromagnetic switching valve 42 is set to the return position and the fuel is returned from the return hole 30 into the fuel tank 1. When the water sensor 45 detects water, the electromagnetic switching valve 42 is switched to the drain position to drain the water from the drain hole 32 to the outside of the fuel tank 1.

Therefore, the water is forcibly pumped up by the pump 22 and drained to the outside of the fuel tank 1. Therefore, even if dust or rust is mixed in the water to be pumped, the pumping pipe 8, the fitting hole 6, the communication hole 28 ,
The drainage hole 32, the valve body 34, the second valve seat 31, etc. can be discharged to the outside without dust or rust adhering to them. Therefore, it is possible to prevent deterioration of the drainage function due to adhesion of dust and rust. Further, the fuel is pumped from the bottom 1a of the fuel tank 1 and discharged from the supply port 2 to the outside. Therefore, when the operation of the pump 22 is stopped, the pumping of water is stopped, and even if the communication between the communication hole 28 and the drain hole 32 is not completely blocked by the electromagnetic switching valve 42, water and fuel will not leak out. Absent.

Further, the water sensor 45 detects water, and when the water is pumped, the communication hole 28 and the drain hole 32 are connected to each other, so that only the water accumulated at the bottom 1a of the fuel tank 1 is appropriately discharged. . Therefore, the fuel is not erroneously discharged, and a part of the fuel is not discharged, which leads to waste of fuel or danger of fire.

The present invention is not limited to the embodiments as described above, and can be implemented in various modes without departing from the gist of the present invention.

[Advantages of the Invention] As described in detail above, in the fuel tank drainer of the present invention, water is forcibly pumped up by the pump and drained to the outside of the fuel tank, so dust and rust may adhere. Without stopping, the drainage function can be prevented from decreasing, and when the pump operation is stopped,
The pumping of water stops and no fuel leaks. Also, water is detected by the water sensor and communicates with the drain hole, so only the water accumulated at the bottom of the fuel tank can be properly discharged,
The fuel is not accidentally discharged, and a part of the fuel is not discharged, so that there is no risk of waste of fuel or danger of fire.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a water draining device for a fuel tank as one embodiment of the present invention, FIG. 2 is a block diagram of an electronic control circuit of this embodiment, and FIG. 3 is a diagram of signals in each circuit of this embodiment. It is a time chart explaining a state. 1 ... Fuel tank, 2 ... Supply port 6 ... Fitting hole, 8 ... Pumping pipe 14 ... Pump shaft, 22 ... Pump 25 ... Water conduit, 27 ... Water detection sensor 28 ... Communication Hole, 30 ... Return hole 32 ... Drain hole, 42 ... Electromagnetic switching valve 45 ... Water sensor, 50 ... Electronic control circuit

Claims (1)

[Claims] 1. A water level detection sensor for detecting that the water level of water accumulated at the bottom of a fuel tank for storing fuel reaches a predetermined level, and when the water level detection sensor detects that water has accumulated A water sensor for detecting water pumped through the water conduit, wherein a pump for pumping through the water conduit extending from the upper port of the fuel tank toward the bottom is arranged. When water is detected by, the return position, which communicates the return hole opened in the fuel tank with the water guide passage, is changed to the drain position, which communicates the drain hole and the water guide passage, which communicate with the outside of the fuel tank. A drainage device for a fuel tank, which is provided with a drainage mechanism for switching.