JP2582529B2 - Combustion device fuel supply - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention adjusts the flow rate of fuel supplied to a nozzle by constantly feeding a fixed amount of liquid fuel to a spray nozzle, returning a part of the liquid fuel from the nozzle, and changing the return amount. The present invention relates to a fuel supply device for a combustion device.

[0002]

2. Description of the Related Art A fuel supply device for a combustion device of this type obtains a good spray state by constantly sending a constant amount of oil guided from an oil tank to an oil feed pipe to a spray nozzle by a fuel pump. The amount of combustion is adjusted by changing the amount of oil returned from the spray nozzle to the oil feed pipe upstream of the fuel pump via the oil return pipe.

[0003]

However, in such a fuel supply device for a combustion device, air may be sucked into the spray nozzle from the tip. Then, the air is mixed into the oil returned from the spray nozzle into the oil return pipe, enters the oil feed pipe, and reaches the fuel pump.

As a fuel pump, a compression-type liquid pump using a piston and a cylinder is generally used.
When the amount of air mixed into the oil increases, the compression capacity of the pump decreases extremely and the pressure on the high pressure side drops.As a result, the spray flow rate from the spray nozzle drops sharply, and the air-fuel ratio reaches the limit value. It may go down and misfire.

Therefore, according to the present invention, even if a considerable amount of air is mixed in the liquid fuel supplied to the fuel pump, the fuel feed operation of the fuel pump can function normally and good combustion can be maintained. An object of the present invention is to provide a fuel supply device for a combustion device.

[0006]

In order to achieve the above object, a fuel supply device for a combustion apparatus according to the present invention is provided such that a constant amount of liquid fuel is always fed from a feed line to a spray nozzle. A fuel pump inserted in the middle, a return line for returning a part of the fuel from the spray nozzle to a junction where the fuel line is merged with the feed line on the upstream side of the fuel pump, and a return line for the return line. In a fuel supply device of a combustion device provided with a return line valve for changing a flow path area,
The flow passage area of the return pipe is narrowed immediately before the junction so that the junction is located at a pressure-reducing portion caused by the flow velocity of the liquid fuel passing through the throttle.

[0007]

[Function] Since the return pipe is narrowed immediately before the junction,
The liquid fuel returned from the return pipe to the junction has a high flow velocity at the junction and is decompressed. As a result, the fuel in the upstream feed pipe is sucked into the junction, and as a result, the pressure of the liquid fuel sent from the feed pipe downstream of the junction to the fuel pump is increased.

[0008]

An embodiment will be described with reference to the drawings. FIG. 1 shows an embodiment of the present invention, in which oil in an oil tank 1 is fed by an oil feed pipe 3 inserted in the middle of an oil feed pipe 3 that connects the oil tank 1 and a spray nozzle 2. A constant amount is always sent to the spray nozzle 2 through the pipe 3.

As a result, the spray nozzle 2 can always obtain a good spray state regardless of the amount of combustion. As the fuel pump 4, a compression-type liquid pump that feeds fuel by reciprocating a piston in a cylinder is used.

In the oil feed pipe 3 upstream of the fuel pump 4, there is formed a feed pipe restricting portion 5 having a narrow pipe diameter and a narrow flow passage area. A ball-shaped feed pipe valve 6 is arranged to change the road area.

The feed pipe valve 6 is driven forward and backward by a solenoid 10 arranged on the upstream side of the feed pipe throttle section 5. 11 is an electromagnetic coil of the solenoid 10, 12 is a movable iron core, 13 is a fixed iron core, and 14 is a rod arranged between the feed pipe valve 6 and the movable iron core 12 so as to push the feed pipe valve 6. It is.

The feed pipe valve 6 is urged by a compression coil spring 15 from a direction opposite to the solenoid 10. Therefore, the feed pipe valve 6 stops at a position where the thrust of the solenoid 10 and the urging force of the compression coil spring 15 are balanced. A spring receiving nut 16 supports the fixed end of the compression coil spring 15.

A rod abutting on the compression coil spring 15 projects from the center of a spring receiver 18 which receives the movable end side of the compression coil spring 15, and a disc-shaped rubber valve 19 is disposed around the rod. , Feed pipe constrictor 5
When the rubber valve 19 is pressed against the annular projection at the inlet of the oil supply pipe 3, the oil feed pipe 3 is completely closed and the flow of oil becomes zero.

All of the petroleum sent to the spray nozzle 2 is sprayed in the tip of the spray nozzle 2, and a part of the oil is sent via the oil return pipe 21 to the fuel pump 4 and the upstream feed thereof. The oil flows into the junction 22 where it joins with the oil feed pipe 3 between the pipe narrowing section 5 and is returned to the oil feed pipe 3.

Therefore, the oil return pipe 2
By changing the amount of oil returned to the oil feed pipe 3 through 1, the amount of oil sprayed from the spray nozzle 2 to the combustion section in front of it and subjected to combustion is controlled.

At the junction 22, as shown in FIG. 2, the oil return pipe 21 is connected straight to the oil feed pipe 3 (3 b) downstream of the junction 22, and
The more upstream oil feed pipe 3 (3a) is open on its side.

The oil return pipe 21 is formed with a return pipe narrowing section 23 having a flow path area smaller than the front and rear flow paths at a position immediately before the junction section 22, and a ball-shaped return pipe path is formed therein. A valve 24 is arranged facing the oil return pipe 21 side.

Therefore, the oil return pipe 21 is connected to the oil feed pipe 3
The oil returned to the passage passes through the return pipe narrowing section 23, so that the flow velocity increases at the merging section 22 and is reduced. Then, thereby, the upstream oil feed pipe 3 (3a)
The oil inside is sucked out to the junction 22 side and sent to the downstream oil feed pipe 3 (3b), and as a result, the pressure of the oil in the downstream oil feed pipe 3 (3b) is increased.

At this time, the pressure in the oil feed pipe 3 is
The downstream side 3b is higher than the upstream side a, but due to the difference in dynamic pressure in the flow path from the oil return pipe 21 to the junction 22, the upstream oil feed pipe 3a moves toward the downstream oil feed pipe 3b. Oil flows.

For example, even if the pressure in the upstream oil feed pipe 3a is 0.9 atm lower than the atmospheric pressure, the pressure in the downstream oil feed pipe 3b depends on the state of the oil return pipe 21. For example, about 1.3 atm.

Then, the volume of the air mixed with the oil in the oil feed pipe 3b on the downstream side is reduced by (0.9 / 1.3) times as compared with the mechanism in which the return pipe throttle 23 is not provided.
In this state, it is sent to the fuel pump 4.

Accordingly, the decrease in the compression capacity of the fuel pump 4 due to the mixing of air is reduced, and even if air is mixed in the oil, an amount of oil close to a predetermined amount can be constantly sent to the spray nozzle 2.

The return pipe valve 24 is urged toward the return pipe throttle 23 from the oil return pipe 21 side by a compression coil spring 26. 27 is a compression coil spring 2
Numeral 28 is a nut for adjusting the urging force of the compression coil spring 26 by receiving the movable end side of the valve 6 and transmitting the urging force to the return pipe valve 24. Around the portion, a filter type rust removing filter 29 is disposed in order to remove iron rust and the like mixed into the oil in the oil return pipe 21.

Reference numeral 30 shown in FIG. 1 is a diaphragm made of a flexible thin film which can be displaced in a direction perpendicular to the plane.
For example, it is formed of a polyimide resin or a tetrafluoroethylene resin.

The inner and outer surfaces of the diaphragm 30 are connected so that the internal pressures of the oil feed pipes 3 on the downstream and upstream sides of the feed pipe restricting section 5 are applied. And the diaphragm 30
A rod 32 is interposed between the diaphragm receiving plate 31 receiving the inner surface side and the return pipe valve 24 so as to be able to advance and retreat in the axial direction.

Therefore, a differential pressure in the oil feed pipe 3 before and after the feed pipe restrictor 5 is applied to the diaphragm 30, and the differential pressure resists the urging force of the compression coil spring 26, and causes the return pipe valve 24 to move. Acts in the opening direction.

As a result, the return pipe valve 24 is controlled by the oil return pipe 2 so that the pressure difference between the front and rear of the feed pipe restrictor 5 applied to the diaphragm 30 and the urging force of the compression coil spring 26 are balanced.
1 by increasing or decreasing the flow passage area,
The amount of oil returned to 2 is controlled so that the differential pressure across the feed pipe restrictor 5 is always kept constant.

The flow rate of the oil flowing through the feed pipe restrictor 5 is the flow rate of the oil consumed by the spray nozzle 2, that is, the flow rate of the oil used for combustion in the combustion section. Is maintained constant, so that the flow rate of the oil supplied to the combustion is determined only by the flow passage area of the feed pipe restricting portion 5.

Therefore, by controlling the movement of the feed line valve 6 by the solenoid 10, the flow rate of the oil supplied to the combustion is directly and accurately controlled, and the oil returned to the oil return pipe 21 is followed by the oil flow. Flow rate changes.

In the middle of the oil return pipe 21 between the return pipe valve 24 and the spray nozzle 2, the oil return pipe 2 on the return pipe valve 24 side
A constant differential pressure valve 50 for maintaining the pressure in the oil return pipe 21 on the spray nozzle 2 side higher than the pressure in the spray nozzle 2 by a constant pressure is inserted. The constant differential pressure valve 50 is formed by pressing a rubber packing 54 against a valve seat by a compression coil spring 53.

As described above, by providing the constant differential pressure valve 50 in the middle of the oil return pipe 21, even if the pressure in the oil return pipe 21 at the return pipe valve 24 becomes lower than the atmospheric pressure, the spray nozzle 2 side Thus, the pressure inside the oil return pipe 21 can be always maintained higher than the atmospheric pressure.

As a result, even when the installation position of the oil tank 1 is lower than that of the fuel supply device, the phenomenon that air is sucked into the oil return pipe 21 from the tip of the spray nozzle 2 when the amount of combustion is reduced does not occur. .

The present invention is not limited to the above-described embodiment. For example, as shown in FIG.
The specific structure can take various forms, such as forming the portion into a Venturi tube.

[0034]

According to the present invention, the return pipe is narrowed immediately before the junction, so that the junction is located at the pressure-reducing portion due to the flow velocity of the liquid fuel passing through the throttle, so that the upstream side is formed. The fuel in the feed pipe is sucked into the junction, the pressure of the liquid fuel sent from the junction to the fuel pump is increased, and the volume of air mixed in the fuel sent to the fuel pump is reduced. Therefore, more fuel is sent to the fuel pump by that amount, and as a result, the decrease in the compression capacity of the fuel pump due to air mixing becomes small, and even if air is mixed in the oil, the amount of oil close to the predetermined amount is reduced. Can be constantly sent to the spray nozzle, and a good combustion state due to a good spray state can be maintained.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a first embodiment of the present invention.

FIG. 2 is a partially enlarged cross-sectional view of the first embodiment of the present invention.

FIG. 3 is a partially enlarged sectional view of a second embodiment of the present invention.

[Explanation of symbols]

 2 Spray nozzle 3 Oil feed pipe 4 Fuel pump 21 Oil return pipe 22 Merging section 23 Return pipe throttle section 24 Return pipe valve

Claims (1)

(57) [Claims] 1. A fuel pump interposed in the middle of a feed pipe so as to constantly feed a fixed amount of liquid fuel from a feed pipe to a spray nozzle, and merges with the feed pipe at an upstream side of the fuel pump. A return line for returning a part of the fuel from the spray nozzle to the merging section to be joined, and a fuel supply device of a combustion device provided with a return line valve for changing a flow area of the return line, A fuel for a combustion apparatus, wherein the flow passage area of the return pipe is narrowed immediately before the junction so that the junction is located at a pressure-reducing portion caused by the flow velocity of the liquid fuel passing through the throttle. Feeding device.