JPS5941654A - Automatic drain type fuel filter - Google Patents

Abstract

PURPOSE:To keep off the outflow of fuel oil, by opening a drain solenoid valve when separated water from a water sump part in a fuel filter is collected more than a fixed water level, and discharging the separated water out automatically, while closing the said valve without fail when it comes into a specified low level. CONSTITUTION:When fuel oil enters inside a casig 11 from an inlet 13 and flows out of an outlet 14 by way of a filter body 12, waterdrops in the fuel oil are collected on the bottom of the casing 11 by its dead load or separation at the filter body 12. When a level of separated water rises by degrees whereby it comes to dip a high level detection electrode 32, an electric current flows from the electrode 32 to the metal casing 11 and a transistor Tr1 inside a control circuit 5 is turned to ON. As a result, a thyristor SCR is conducted, turning a transistor Tr3 to ON and energizing a coil 45 with a continuous rating current whereby a drain solenoid valve 4 is opened so that the separated water is discharged outside. When the separated water drops more than a low level detection electrode 33, a transistor Tr2 becomes unconducted and the thyristor SCR comes into a state of extinction of arc, and the transistor Tr3 also becomes unconducted, thus the drain solenoid valve 4 is closed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel filter with an automatic drainage device and equipped with a water level detection means for use in an internal combustion engine.

The fuel filter has all the functions of removing dust contained in fuel oil such as light oil and separating water from the fuel oil. A water reservoir for storing this separated water is provided at the bottom of the casing of the fuel filter, and when decomposed water accumulates above a certain water level, the user is notified of the water level and the drain solenoid valve is automatically opened to separate the water. A device is known in which water is discharged to the outside from a drain hole at the bottom of the fuel filter.

This water level detection device has a high water level detection electrode and a low water level detection electrode, and when it detects water that has reached the high water level detection electrode, it activates a water extraction solenoid valve to separate it. Drain the water. Then, when the water level of the separated water becomes lower than the low water level detection electrode, the drain solenoid valve is stopped. However, even if the water level of the separated water is lower than the low water level detection electrode, some of the separated water remains in a band shape on the synthetic resin cylinder, and the low water level detection electrode valves the remaining water and conducts it with the metal casing. Because of this, the drain solenoid valve remained open, which could cause fuel oil to be discharged to the outside and cause a fire.

The present invention provides an automatic drainage fuel filter device that eliminates all of these drawbacks, and is intended to provide an automatic drainage fuel filter device that eliminates all of these drawbacks, and in which the water level of separated water is electrically connected to the low water level detection electrode through a band-shaped water impregnated with the low water level detection electrode and metal. Taking advantage of the fact that the resistance value between the casing is greater than the resistance value when the water level is at the same level as the low water level detection electrode, the resistance value between the water level detection electrode and the metal casing is set and the drain solenoid valve is activated. It is designed to stop the operation of the

In the following, the details will be explained in detail below.In FIG. Drainage v1. It consists of a magnetic valve 4 and a drainage solenoid valve control circuit 5. The fuel filter main body 2 includes a filter pan body 1 pressed by a spring 17 inside a metal cup-shaped casing 11.
2 (-7, an enclosure crimped to the periphery of the open end of the cover plate housing 11, which has an outlet part 14 provided with a screw fjt- in the central rising part and a plurality of inlets 13 provided around it) A sheet 15 consisting of a plate 16 is fixed in a liquid-tight manner.

The water level detection device 3 has a high water level detection electrode 4 @ 32 at the two ends of the synthetic resin oil body 31, and a low water level detection electrode 36 at the lower end.
are provided with terminals 34 and 35 connected to each electrode.
It is inserted into the first nosig (-) 18 at the bottom of the metal casing 11. Casing 11F r;3
A drain solenoid valve 4 is disposed on the VC through a puffkin 41 (-) to open and close a drain passage 43 formed in the second plug seat 19.

Drainage solenoid valve 4 Ff Valve 44 with a gasket 42 at its tip
It consists of an excitation coil 45 that activates the p44 metal operation and a spring 46 that biases the valve 44 in the direction of closing it.
, by excitation coil 45 and diaphragm 47" JF: Mizutsu i ¥845'.

There is a partition tl from 48.

When the drain electromagnetic valve control circuit 5 is shown in FIG. 2, it is connected to the paitch 51 through a 52nd power source. The anode side of the diode DIl is connected to the switch 51 42, and the diode T
)l is connected to the high water level detection terminal 34 via resistors R8, R, and tt. ZnR is a varistor whose one end is connected to the cathode of the diode I)+ and whose other end is all grounded. The transistor Tr+ connects the emitter to the cathode terminal of the diode. Its base is connected to the connection point of the resistor R are doing. The gate is connected to the +a connection point of resistor R1 and resistor R4.
thyristor SCRIr,t, its anode resistance R6
The capacitor 1' is connected to the transistor Trt through the resistor R1, and the capacitor 1' is grounded through the resistor R1. This thyristor 5 (j
A resistor R3 is connected to VC between the cathode and gate of t. The transistor Trs has its base connected to the connection point A between the cathode of the thyristor SCR and the resistor R1, and has its collector connected to the cathode of the diode D at one end of each transistor Trs, and the excitation coil 45. Diode D
3 and the emitter tube is grounded.

The automatic drain fuel filter 1V having such a configuration, the CS fuel oil flows into the filter body 11 from the inlet 15 of the filter body 20, passes through the filter body 12, and flows out from the outlet 14. The water droplets are collected in one layer or by the sowing body 12 and collected at the bottom of the casing 11. The metal casing 11 is immersed in water for one minute to the low water level detection electrode 33 at the lower end of the water level detection device jFt in the Kuosong 11.
A current is passed through the Then, in order to create the transistor Try in the resistor R8, the transistor Tr, which generates a potential difference sound, is necessary.
conduction. On the other hand, what about wood vinegar detection equipment? , 3 While the high water level detection electrode 52 at one end of J is in contact with fuel oil, the electrical conductivity of the fuel is small and the resistance between the detection electrode 62 and the metal cage 11 is extremely large, so the resistance R3 is In this case, the potential difference required to operate the transistor Trl is not generated, and the drain solenoid valve 4 is not operated.

When the separated water gradually rises and immerses the high water level detection electrode 32, a current flows from the detection electrode 32 to the metal casing 11 due to the high conductivity of the water. Then, a potential difference sufficient to activate the transistor Tr+ is generated in the resistor R1, making the transistor Tr+ conductive. When the transistor Tr+ becomes conductive, the amplified current flows through the light emitting diode Dt and the resistor R8 to the gate of the thyristor SCH.
The thyristor SCH, which is prevented from firing, causes current to flow to the base of the transistor Trm, making the transistor Trs conductive. When the transistor Tra conducts, the excitation coil 45 receives an excessive amount of power necessary to operate the valve 44. The current flows to open the valve 44 and start draining the water accumulated at the bottom of the casing 11. At the same time, the indicator lamp LP is lit to indicate that the water is being drained.

The low water level detection electrode 33 is electrically connected to the metal casing 11, thereby bringing the transistor Trt into electrical continuity. As shown in FIG. 3, when the water level 60 of the separated water reaches the same level as the low water level electrode 33, the transistor Tr remains fully conductive.

At this point, the voltage appearing across the bias resistor R8 is
This becomes a critical voltage that can cause the transistor/transistor Tr2 to fully operate σ. r, setting the resistance value between the low water level detection electrode 56 and the metal casing 11;

When the water level 60 of the separated water falls below the position of the low water level detection electrode 56, a strip 61 remains on the resin cylinder 31 as shown in FIG.
If conduction 17 occurs through the strip of water, current flows to the metal casing, which in turn causes the transistor Try to conduct. However, the resistance between the detection pole 36 and the metal casing 11 is large (16) due to the water in the band 61, and the potential difference IL appearing in the resistance R♂ is the total transistor Tr.
When y is activated, the potential difference is made smaller than the critical value and the transistor Trt becomes non-conductive.
Since the flefter current of r t no longer flows to the thyristor SCR, the iris resistor 5CRI'' is turned off, the transistor T r s also becomes non-conductive, and the current of the excitation coil 45 of the drain solenoid valve 4 is cut off, and the valve 44 is completely closed. Close zero lamp LP
Also turn off the lights.

As described above, according to the present invention, when the water level of the separated water is equal to or higher than that of the low water level detection electrode, a critical potential difference that can activate the transistor appears in the potential difference of the resistance of the low water level detection electrode circuit. ! ] Since the resistance value between the low water level detection electrode and the metal casing is set so that the low water level detection e1. Even if the electrode and the gold casing are electrically conductive, there is no potential difference to activate the low water level detection electrode circuit resistance Kl-ra/'), so close the drain solenoid valve and drain the fuel oil externally. It is excellent for saving fuel oil and preventing fires. .

[Brief explanation of the drawing]

FIG. 1c is a vertical sectional view of an automatic drainage fuel filter device which is an embodiment of the present invention. Figure 2 shows the drainage solenoid. The wiring diagrams of the valve control circuit, FIGS. 3 and 4, are diagrams showing the positional relationship between the water level of separated water and the low water level detection electrode. 1... Automatic drainage fuel filter device 5... Water level detection device 4... Drain solenoid valve 11... Metal casing 32... High water level detection electrode 33...
・Low water level detection electrical connection R Todoroki...bias resistance

Claims (1)

[Claims] Inside the housing, which is liquid-tightly fixed with a sheet having a fuel oil outlet and a metal cup-shaped casing, a filter body is housed, and a water level detection device and a drain solenoid valve are arranged at the bottom of the casing, and the water level of the separated water is The resistance value between the low water level sensing electrode and the metal casing is set so that the potential difference of the bias resistor of the transistor in the low water level sensing electrode circuit becomes the critical voltage difference for operating the transistor when the voltage is the same level or higher than that of the low water level sensing electrode. It all features an automatic drain fuel filter device.