JPS622292Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a device for supplying fuel oil to a diesel engine.

Recently, due to the rise in fuel costs, the quality of fuel oil used in diesel engines such as marine main engines has become lower in quality (ie, higher in viscosity and higher specific gravity). In order to supply such inferior oil to an engine with an appropriate viscosity, the heating temperature must be raised sufficiently.
However, poor-quality oil has a high specific gravity, making it difficult to separate water by specific gravity, and contains as much as 4% water. Therefore, when used at high temperatures as mentioned above, the water in the oil boils in the tank, causing
There is a problem in that water vapor entrains oil and blows out of the vent pipe. Similar problems arise when using so-called emulsion fuels (emulsions of water particles dispersed in oil).

In order to solve this problem, this invention aims to suppress the boiling of water in the oil by applying pressure to the oil surface of the return chamber.

This invention will be explained with reference to the drawings. In FIG. 1, 1 is a diesel engine for propulsion of a ship, and a fuel service tank 2 is placed at a higher position than this. 2a is a ventilation pipe. The fuel oil in this tank is gravity fed along main line 3 to fuel supply pump 4 . After being pressurized by the same pump, the fuel oil passes through a fuel heater 5, e.g.
It is heated to 130-140°C and reaches the diesel engine 1. Of course, the heating temperature is determined in consideration of the engine and the type of fuel oil. A portion of the fuel oil that has reached the engine 1 is injected into a cylinder from a fuel injection pump 6 attached to the engine and combusted. The remaining oil flows through a return oil pipe 7 into a return chamber 8, which is a vertically elongated tank. The fuel oil is returned to the suction side of the fuel supply pump 4 after gases such as air contained in the return chamber are separated and pressure pulsations are removed at the same time. The returned fuel oil flows toward the engine 1 again together with the fuel oil sent from the service tank 2. The gas separated from the fuel oil accumulates in the upper part of the return chamber 8 and is discharged to the outside air through the exhaust device 11. In the conventional fuel system, this exhaust system consisted of only a vent pipe, but in this invention, a trap 9 is provided between the vent pipe 10 and the return chamber 8.

The trap 9 is similar to the deodorizing trap for exhaust pipes found in ordinary houses, and various types such as a simple U-shaped pipe filled with sealed water can be used.
As shown in FIGS. 2 and 3, this embodiment consists of an outer cylinder 12 and an inner cylinder 13, and the liquid surface of the sealing water 14 accumulated at the bottom of the outer cylinder is divided into the inside and outside of the inner cylinder. .
Then, the liquid level outside the inner cylinder 13 is applied with the upper pressure of the return chamber 8 through the pipe 16 connected to the inlet 15, and the liquid level inside the inner cylinder 13 is applied to the liquid level at the outlet 17.
Atmospheric pressure is applied through a ventilation pipe 10 connected to the air.
Furthermore, the trap 9 is equipped with a water supply line 18 for supplying sealed water before operation, a detection valve 20 for checking the level of sealed water, and a drain line 19 for discharging the sealed water.

As shown by the chain line in FIG. 2, when seal water is stored in the trap 9 and the engine 1 is operated, gas separated from the fuel oil that has flowed into the return chamber 8 accumulates in the upper part of the chamber, and the liquid level on the inlet side of the water seal 14 The pressure applied to the outlet increases, the liquid level decreases, and the outlet side liquid level rises. As this condition progresses, the sealed water will eventually overflow from the outlet 17 (the overflowing water will be collected from the bottom of the vent pipe 10 through the drain line 19a), the liquid level on the outlet side will remain at a constant level, and the liquid on the inlet side will be recovered. The surface reaches the same level as the lower end of the inner cylinder 13. At this time, the upper pressure of the retentive chamber 8 is equivalent to the water head pressure of the sealed water at the depth h. When the upper pressure of the chamber further increases from this state, the water seal breaks at the lower end of the inner cylinder 13, and the gas inside the chamber rises up in the form of bubbles inside the inner cylinder, passes through the outlet 17 and the vent pipe 10, and enters the atmosphere. inside, and the pressure at the top of the retardant chamber therefore decreases. In this way, a constant holding pressure p higher than atmospheric pressure can be applied to the oil level in the return chamber 8, and as a result, even if the fuel oil flows into the return chamber at a high temperature exceeding 100°C, the fuel This prevents the water contained in the oil from boiling. In this embodiment, the holding pressure p is set to a value of approximately 0.3 kilograms per square centimeter when the water sealing depth h is 3 meters. If this value is made too large, it will place a burden on the entire fuel system, so it should be made as small as possible within the range that allows for the generation of water vapor. If the amount of water vapor produced by partially boiling the water in the fuel oil is not large, it will condense in the sealed water while passing through the sealed water, so it will be drained as water that continuously overflows from the trap 9. It can be collected from line 19a. Since gases other than water vapor are also cooled by the sealed water, high-temperature gas is not discharged from the vent pipe as in conventional devices. Note that, within the scope of this invention, it is also possible to continue supplying water from the water supply line 18 to the trap during operation in order to increase the cooling capacity of the trap.

After the engine has stopped, when the inside of the return chamber cools and becomes negative pressure, the liquid level on the outlet side of the sealing water will drop, and as the negative pressure increases, the liquid level will drop to the lower end level of the inner cylinder 13, and air will flow into the chamber. Allow me to enter 8.
In this case, the water is sealed from the inlet 15 to the return chamber 8.
In this embodiment, the height relationship between the inlet and outlet and the cross-sectional area ratio of the outer cylinder 12 and the inner cylinder 13 are taken into consideration to prevent overflow.

Figure 4 shows a modification of the exhaust system.
According to this, a plurality of traps 9 having the same structure as described above are connected in series. With this configuration, a head pressure equal to the water sealing depth of each trap multiplied by the number of traps can be applied to the return chamber 8. Furthermore, by removing the water seal from some of the traps, the holding pressure p can be changed in stages. Therefore, it is possible to deal with a wide range of fuel oils having different properties.

As explained above, this device uses a trap to apply a constant pressure to the oil surface in the retancture chamber, which suppresses the boiling of the water in the oil in the chamber, preventing it from boiling partially. The generated water vapor can be collected by condensation in sealed water within the trap. Therefore, it is possible to prevent water vapor from spewing out from the ventilation pipe, which has been a problem with conventional devices.
Further, since the gas discharged from the vent pipe is cooled while passing through the sealed water in the trap, there is no risk of fire or the like. Moreover, since the trap does not have any moving parts such as springs, high reliability can be achieved.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention. FIG. 1 is a system diagram of a fuel system, FIG. 2 is a system diagram of the exhaust system of FIG. 1, FIG. 3 is a perspective view of the main part of the trap of FIG. 1 and FIG. 2, with a part cut away, and FIG.
The figure shows a system diagram of the exhaust system according to another embodiment of the present invention. 1 ... diesel engine, 4 ... fuel supply pump, 6 ... fuel injection pump, 7 ... return oil pipe, 8
...Ritanthamba, 9...Trap, 10...
Ventilation pipe, 11...exhaust system, 14...water seal.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. A fuel supply pump that pressurizes a diesel engine's fuel injection pump with a flow rate of fuel oil that exceeds the injection amount, and for returning excess fuel oil to the suction side of the fuel supply pump. In a fuel system consisting of a return oil pipe, a return chamber placed in the middle of this pipe, and an exhaust device for discharging the gas accumulated in the upper part of this chamber to the outside, the exhaust device has a trap and a vent pipe. This trap has an outer cylinder that stores sealed water, and an inner cylinder that is placed inside the outer cylinder so that the lower part is immersed in the sealed water. The pressure in the upper space of the return chamber is applied to the liquid level of
Atmospheric pressure is applied to the other liquid level through a vent pipe, and when the pressure difference exceeds a certain value, the sealed water is pushed up, allowing gas to pass from the high pressure side to the low pressure side. Diesel engine fuel system. 2 Utility model registration claim 1 in which there are multiple traps and they are connected in series
Diesel engine fuel system as described in Section.