JP3286066B2 - 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 system of a combustion apparatus 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 pump via the oil return pipe.

In order to control the amount of combustion accurately,
A return pipe valve for changing the flow area of the oil return pipe, and a throttle section for narrowing the flow area of the oil feed pipe upstream of the junction (the junction of the oil feed pipe and the oil return pipe); Improvements have been made to control the operation of the return line valve by the differential pressure between the oil feed pipes on the upstream side and the downstream side of the throttle section (Japanese Patent Laid-Open No. 5-60).
No. 320).

[0004] According to such an improved configuration, the flow rate of oil supplied to the spray nozzle for combustion is directly determined from the flow area of the throttle portion of the oil feed pipe and the differential pressure across the pipe, Since the return flow rate from the spray nozzle only changes in accordance with it, the flow rate of petroleum oil used for combustion can be directly and accurately controlled.

[0005]

In such a fuel supply apparatus for a combustion apparatus, a feed pipe valve for changing the flow path area of the throttle portion is conventionally driven by a motor, so that a potentiometer or other control device is used. Is required, and the manufacturing cost is relatively high.

Therefore, if the feed pipe valve is driven by a solenoid, the flow path area can be easily changed only by controlling the current value, so that the manufacturing cost can be considerably reduced.

However, since a large thrust cannot be produced by the solenoid, it is difficult to stop oil from entering the movable iron core using a sealing O-ring or the like. This is because if a sliding resistance due to an O-ring or the like is applied to the movable iron core, a large error will occur in the control of the solenoid.

Therefore, if a solenoid is used to drive the feed pipe valve, the oil feed pipe and the movable iron core of the solenoid are in communication. Then, air accumulated in the movable iron core portion at the time of assembling may come out to the oil feed pipe side during operation at a later date and the fuel pump may not work, and the apparatus may stop.

Also, iron rust powder and the like flowing into the oil may be attracted to the movable iron core by magnetic force and may be accumulated, so that the solenoid may be in a so-called electromagnetic lock state and may not move.

In the present invention, a feed pipe valve for changing a flow path area of a throttle section of a feed pipe is driven by a solenoid, and furthermore, air or iron rust powder or the like does not accumulate in a movable iron core portion, so that normal operation is performed. It is an object of the present invention to provide a fuel supply device for a combustion device that can be continued.

[0011]

In order to achieve the above object, a fuel supply device for a combustion device according to the present invention is provided in the middle of the feed pipe so that a constant amount of fuel is constantly fed from the feed pipe to a spray nozzle. An interposed fuel pump, a throttle section for narrowing the flow area of the feed pipe on the upstream side of the fuel pump, a feed pipe valve for changing the flow area of the throttle section, and the fuel pump and the throttle. A return pipe for returning a part of fuel from the spray nozzle to a junction where the feed pipe merges with the feed pipe; a return pipe valve for changing a flow area of the return pipe; And a differential pressure operating means operating by the differential pressure in the feed pipe on the upstream and downstream sides to control the operation of the return pipe valve. A cylinder with one end communicating with the pipe The feed pipe valve is driven by a solenoid having a movable iron core that slides in the cylinder, and the outlet end of the return pipe is connected to the other end of the cylinder. And

[0012] A rust removing filter for removing iron rust powder from the fuel flowing through the return pipe may be provided in the middle of the return pipe.

[0013]

The fuel flowing from the spray nozzle into the return pipe is returned to the feed pipe through the cylinder in which the movable iron core slides,
Foreign matter in the cylinder flows out to the feed pipe.

If a rust removing filter is provided in the middle of the return pipe, the inside of the solenoid cylinder is washed away by fuel free of iron rust, and there is no accumulation of iron rust powder near the movable iron core.

[0015]

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,
In the spray nozzle 2, a good spray state can always be obtained regardless of the amount of combustion.

In the oil feed pipe 3 on the upstream side of the fuel pump 4, there is formed a throttle portion 5 having a narrow pipe diameter and a narrow flow passage area. The flow passage area of the throttle portion 5 is changed. Needle-like feed pipe valve 6 is arranged so as to enter and exit from the downstream side in throttle section 5.

The feed pipe valve 6 is driven forward and backward by a solenoid 10 disposed downstream of the throttle section 5.
11 is an electromagnetic coil of the solenoid 10, 12 is a movable iron core,
13 is a compression coil spring for urging the movable iron core 12 forward,
A spring receiving nut 14 receives one end of the compression coil spring 13.

The movable iron core 12 is an elongated cylindrical cylinder 1.
5 is disposed so as to be slidable in the axial direction, and the inner end side of the cylinder 15 is located immediately downstream of the throttle unit 5 (therefore,
(Between the throttle portion 5 and the fuel pump 4).

The feed pipe valve 6 is formed at the tip of a rod 16 inserted into the tip of the movable iron core 12, and the rod 16 has a thickness in order to close an excessively wide gap between the cylinder 15 and the rod. A meat cylindrical body 17 is attached.

Grooves 12a and 17a are formed in the movable iron core 12 and the cylindrical body 17 in the vertical direction so that oil can flow in the cylinder 15 in the tube axis direction without resistance.

When the distance between the tip of the movable iron core 12 and the oil feed pipe 3 (the length of the cylindrical body 17) is, for example, 20 mm or more, iron rust powder in oil flowing through the oil feed pipe 3 can be used. Is effective to prevent the armature from entering the position of the movable iron core 12, and it is more preferable to set it to 30 mm or more.

The cylindrical body 17 is provided with a second compression coil spring 18.
The feed pipe valve 6 is stopped at a position where the urging force of the coil springs 13 and 18 and the electromagnetic thrust applied to the movable iron core 12 of the solenoid are balanced.

When the rubber valve 19 attached to the inner end surface of the cylindrical body 17 is pressed against the annular projection formed around the throttle section 5, the oil feed pipe 3 is completely closed and the oil feed pipe 3 is closed. Flow can be stopped.

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 throttle section 5.
Is returned to the oil feed pipe 3 from the junction 22 where it joins the oil feed pipe 3.

Therefore, from the spray nozzle 2 to 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.

In the present apparatus, oil is applied to the base end of the cylinder 15 in which the movable iron core 12 of the solenoid 10 slides (ie, the end opposite to the side where the feed pipe valve 6 is provided). The outlet end of the return pipe 21 is connected.

Therefore, the oil return pipe 2
Since the oil returned in 1 is returned to the oil feed pipe 3 through the inside of the cylinder 15, if there is air or iron rust powder near the movable iron core, they will be sent out to the oil feed pipe 3 side.

In the middle of the oil return pipe 21, a ball-shaped return pipe valve 24 for changing the flow area of the oil return pipe 21 is provided.
The third compression coil spring 26 biases the valve seat 25 and is disposed. Reference numeral 27 denotes a coil spring receiver, and reference numeral 28 denotes a nut for adjusting the spring force of the compression coil spring 26.

Reference numeral 30 denotes a diaphragm made of a flexible thin film which can be displaced in a direction perpendicular to the surface, and is made of, for example, polyimide resin or ethylene tetrafluoride resin.

The inner and outer surfaces of the diaphragm 30 are piped so that the internal pressure of the oil feed pipes 3 downstream and upstream of the throttle unit 5 is applied. A rod 32 is interposed between the diaphragm receiving plate 31 that receives the diaphragm 30 on the inner surface side and the return pipe valve 24 so as to be able to advance and retreat.

Accordingly, a differential pressure in the oil feed pipe 3 before and after the throttle portion 5 is applied to the diaphragm 30, and the differential pressure resists the urging force of the third 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 increases or decreases the flow area of the oil return pipe 21 so that the pressure difference between the front and rear of the throttle portion 5 applied to the diaphragm 30 and the urging force of the third compression coil spring 26 are balanced. Thus, the amount of oil returned from the spray nozzle 2 to the junction 22 is controlled, so that the differential pressure across the throttle 5 is always kept constant.

The flow rate of the oil flowing through the throttle section 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 path area of the throttle unit 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 return pipe 21 is returned through the oil return pipe 21 in accordance with the control. Flow rate changes.

The oil return pipe 21 at the inlet of the return pipe valve 24
A filter type rust removing filter 35 that does not allow iron rust powder or the like to pass through is disposed in the middle of the third coil spring 26.

As a result, iron rust powder mixed with the oil flowing in the oil return pipe 21 cannot pass through the rust removing filter 35 and accumulates in the rust reservoir 36 around the filter. Iron rust powder is removed from the flowing oil. Therefore, the oil from which iron rust powder has been removed flows into the cylinder 15 of the solenoid 10, and the cylinder 15
The inside can be kept free of iron rust powder.

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

As described above, by providing the constant pressure difference valve 50 in the middle of the oil return pipe 21, even if the pressure in the oil return pipe of the return pipe valve 24 becomes lower than the atmospheric pressure, the spray nozzle 2
On the side, the pressure in the oil return pipe 21 can always be maintained higher than the atmospheric pressure (the spring load of the fourth compression coil spring 53 is set as such).

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 constant differential pressure valve 50 also functions as a check valve for preventing oil in the oil return pipe 21 from flowing back to the spray nozzle 2 side, and greatly reduces the spring load of the fourth compression coil spring 53. If it is made smaller, it will only act as a simple check valve.

[0041]

According to the present invention, the fuel flowing from the spray nozzle into the return pipe passes through the cylinder in which the movable iron core of the solenoid slides and returns to the feed pipe, and thus enters the movable iron core. The air is discharged at the time of the first test operation, and the operation failure of the fuel pump does not occur during the subsequent operation.

Further, since iron rust powder and the like that have entered the movable iron core portion are also flushed out, so-called electromagnetic lock does not occur. If a rust removing filter is provided in the middle of the return line, the effect can be enhanced. Become.

As described above, in the present invention, low cost manufacturing is possible by driving the feed pipe valve with the solenoid, and a stable and normal combustion state can always be obtained.

[Brief description of the drawings]

FIG. 1 is a side sectional view of an embodiment.

[Explanation of symbols]

 Reference Signs List 2 spray nozzle 3 oil feed pipe 4 fuel pump 5 throttle section 6 feed pipe valve 10 solenoid 12 movable iron core 15 cylinder 21 oil return pipe 22 junction 24 return pipe valve 30 diaphragm

Claims (2)

(57) [Claims] 1. A fuel pump inserted in the middle of a feed pipe so as to always feed a constant amount of fuel from a feed pipe to a spray nozzle, and a flow path area of the feed pipe upstream of the fuel pump is reduced. A throttle section, a feed pipe valve for changing the flow area of the throttle section, and a part of the fuel from the spray nozzle to return to a junction where the feed pipe merges between the fuel pump and the throttle section. A return pipe for changing a flow path area of the return pipe, and an operation of the return pipe valve operated by a differential pressure in the feed pipe on an upstream side and a downstream side of the throttle unit. In a fuel supply device of a combustion device having a differential pressure operation means for controlling a cylinder, a solenoid having one end communicating with a feed pipe downstream of the throttle portion and a movable iron core sliding in the cylinder is provided by a solenoid. Above the throttle The feed pipe valve is driven such that the differential pressure in the feed pipe on the downstream side and the feed pipe on the downstream side is constant, and the outlet end of the return pipe is connected to the other end of the cylinder, and Communicate between both ends
A fuel supply device for a combustion device, wherein a groove is formed in the cylinder . 2. A fuel supply device for a combustion apparatus according to claim 1, wherein a rust removing filter for removing iron rust powder from fuel flowing through the return pipe is provided in the return pipe.