JPH07260135A - Fuel supplying apparatus for burner - Google Patents

Abstract

PURPOSE:To maintain excellent combustion by normally performing a function of feeding fuel in a fuel pump even if a substantial quantity of the air is mixed with liquid fuel to be supplied to the pump. CONSTITUTION:The fuel supplying apparatus for a burner comprises a fuel pump 3 so inserted to the mid-way of a feed tube 2 as to always feed a predetermined quantity of liquid fuel from the tube 2 to a spray nozzle 4, a return tube 5 for returning part of the fuel to a confluent part combined with the tube 2 at an upstream side of the pump 3 from the nozzle 4, a return tube line valve 12 for altering a passage area of the tube 5, and booster means 16 for rising a pressure in the tube 2 connected to an inlet of the pump 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention constantly feeds a fixed amount of liquid fuel to a spray nozzle, returns a part of it from the nozzle, and adjusts the amount of return to adjust the flow rate of fuel used for combustion in the nozzle. 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 fixed amount of oil introduced from an oil tank to an oil feed pipe to a spray nozzle by a fuel pump, The combustion amount 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 the fuel supply device for such a combustion device, air may be sucked into the spray nozzle from the tip. Then, the air is mixed in the oil returned from the spray nozzle into the oil return pipe, enters the oil feed pipe, and reaches the fuel pump.

As the fuel pump, a compression type liquid pump using a piston and a cylinder is generally used. However, when the amount of air mixed in oil increases, the compression capability of the fuel pump is extremely lowered. The pressure on the high pressure side drops,
As a result, the spray flow rate from the spray nozzle may suddenly decrease, and the air-fuel ratio may fall below the limit value, resulting in 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 feeding operation of the fuel pump functions 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, the fuel supply device for a combustion apparatus according to the present invention is provided in the middle of the feed pipe so that a constant amount of liquid fuel is constantly fed from the feed pipe to the spray nozzle. A fuel pump inserted, a return pipe for returning a part of the fuel from the spray nozzle to a confluence portion where the fuel pipe joins the upstream side of the fuel pump, and a flow passage area of the return pipe are changed. And a pressure increasing means for increasing the pressure in the feed pipe connected to the inlet of the fuel pump.

[0007]

By increasing the pressure in the feed pipe connected to the inlet of the fuel pump by the pressure increasing means, the volume of air contained in the liquid fuel entering the fuel pump is reduced, and the liquid fuel is added to the extent that the air is compressed. Sent to the spray nozzle.

[0008]

Embodiments will be described with reference to the drawings. FIG. 1 shows a first embodiment of the present invention, in which the oil in the oil tank 1 is removed by a fuel pump 3 which is inserted in the middle of an oil feed pipe 2 which connects the oil tank 1 and the spray nozzle 4 to each other. A fixed amount is always sent to the spray nozzle 4 through the oil feed pipe 2. As the fuel pump 3, a compression type liquid pump that reciprocates a piston in a cylinder to feed fuel is used.

A part of the petroleum oil sprayed in the tip portion of the spray nozzle 4 passes through the oil return pipe 5 and the oil feed pipe 2 from the merging portion 9 which joins the oil feed pipe 2 upstream of the fuel pump 3. Returned to.

Therefore, from the spray nozzle 4 to the oil return pipe 5
By changing the amount of petroleum returned through the spray nozzle 4, the amount of petroleum sprayed from the spray nozzle 4 to the combustion section and provided for combustion is controlled.

On the oil return pipe 5, a ball-shaped return pipe valve 12 for changing the flow passage area of the oil return pipe 5 is provided with a compression coil spring 13 toward a valve seat 11 formed immediately before the confluence portion 9. It is urged by and arranged. 14 is a coil spring receiver. The spring force of the compression coil spring 13 can be adjusted by the adjusting nut 15.

A volume pump 16 (pressurizing means) is provided midway in the oil feed pipe 2 upstream of the merging portion 9 for constantly forcibly feeding a fixed amount of oil in the oil feed pipe 2 to the downstream side. ing.

As shown in FIG. 1, as the positive displacement pump 16, a pair of gears meshing with each other is used.
Both gears are rotationally driven in the arrow direction at a constant speed by a motor (not shown).

As a result, a fixed amount of oil is constantly sent from the oil tank 1 into the oil feed pipe 2, and the positive displacement pump 16
The pressure in the oil feed pipe 2 on the more downstream side is increased from the pressure on the upstream pipe. Therefore, a boosted pressure is applied to the inlet of the fuel pump 3 connected to the oil feed pipe 2 on the downstream side.

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 tetrafluoroethylene resin.

The inner surface and the outer surface of the diaphragm 30 are arranged so that the internal pressures of the oil feed pipes 2 on the downstream side and the upstream side of the positive displacement pump 16 are applied. And the diaphragm 30
A rod 32 is interposed between the diaphragm receiving plate 31 for receiving the inner side of the valve and the return conduit valve 12 so as to be movable back and forth.

Reference numeral 33 is a compression coil spring having a stronger spring force than the compression coil spring 13 of the return conduit valve 12, and biases the diaphragm 30 from the rear in the direction of opening the return conduit valve 12.

Therefore, a differential pressure in the oil feed pipe 2 before and after the positive displacement pump 16 is applied to the diaphragm 30, and the differential pressure resists the urging force of the compression coil springs 13 and 33 to actuate the return line valve 12. It acts in the closing direction.

As a result, the return conduit valve 12 has a flow passage area of the oil return pipe 5 so that the differential pressure across the volumetric pump 16 applied to the diaphragm 30 and the biasing forces of the two compression coil springs 13 and 33 are balanced. By increasing or decreasing, the amount of oil returned from the spray nozzle 4 to the merging section 9 is controlled. Thereby, the differential pressure in the oil feed pipe 2 before and after the positive displacement pump 16 is always kept constant.

Oil tank 1 upstream of the volumetric pump 16
Since the pressure in the oil feed pipe 2 connected to is always atmospheric pressure,
The pressure in the oil feed pipe 2 on the downstream side of the positive displacement pump 16 is always maintained at a constant pressure higher than 1 atm, and the fuel pump 3
The high pressure is applied to the inlet.

According to the apparatus of the embodiment thus constructed, the flow rate of the oil sent by the positive displacement pump 16 is the flow rate of the oil consumed by the spray nozzle 4, that is, the flow rate of the oil used for combustion in the combustion section. The flow rate of oil used for combustion is accurately controlled by the rotational speed of the positive displacement pump 16, and the flow rate of oil returned to the oil return pipe 5 changes accordingly.

Since the high pressure boosted by the volume pump 16 is applied to the oil feed pipe 2 at the inlet of the fuel pump 3, the air mixed with the oil entering the fuel pump 3 is applied. Is smaller, the volume becomes smaller, and extra oil enters the fuel pump 3 as much as the volume of air is contracted.

Therefore, even if the oil entering the fuel pump 3 is mixed with air, the decrease in the compression capacity of the fuel pump 3 is suppressed to a small extent, and the amount of oil close to the predetermined flow rate is constantly sent to the spray nozzle 4. .

In the middle of the oil return pipe 5, a constant pressure for keeping the pressure in the oil return pipe 5a on the spray nozzle 4 side constant higher than the pressure in the oil return pipe 5b on the return pipe valve 12 side. The differential pressure valve 50 is inserted.

The constant differential pressure valve 50 is formed by pressing a ball valve 53 with a compression coil spring 55 against a valve seat 52 formed in the housing 51 in communication with the oil return pipe 5a on the spray nozzle 4 side. . Reference numeral 56 denotes a connection lid that is in communication with the oil return pipe 5b on the return pipe valve 12 side and is airtightly fixed to the other end of the housing 51.
5 is receiving the other end side.

By providing such a constant differential pressure valve 50, even if the installation position of the oil tank 1 is lower than that of the fuel supply device, when the combustion amount is reduced, the inside of the oil return pipe 5 from the tip of the spray nozzle 4 is reduced. It is possible to mitigate or prevent the phenomenon that air is sucked in.

FIG. 2 shows a second embodiment of the present invention, in which a ball-shaped feed pipe for changing the flow passage area of the oil feed pipe 2 is provided on the oil feed pipe 2 upstream of the merging portion 9. The valve 17
It is fixedly arranged at the tip of the rod 18.

The feed line valve 17 is driven back and forth by a motor 21 via a gear mechanism 20 toward a valve seat 19 formed on the downstream side of the feed line valve 17 so as to face the valve seat 19.
The gap between the valve seat 19 and the valve seat 19 is a throttle portion that narrows the oil feed pipe 2 in the middle. A potentiometer 22 is attached to the other end of the rod 18 to detect the axial displacement of the rod 18.

The operation of the motor 21 is feedback-controlled by the control unit 23 based on the detection signal of the potentiometer 22, and the flow passage area of the oil feed pipe 2 can be arbitrarily narrowed down. Reference numerals 25 and 26 are O-rings for sealing and their receiving plates.

The inner pressure and the outer surface of the diaphragm 30 provided in the same manner as in the first embodiment apply the internal pressure of the oil feed pipe 2 on the downstream side and the upstream side of the feed line valve 17 (throttle portion). It is plumbed. A rod 32 is interposed between the diaphragm receiving board 31 that receives the diaphragm 30 on the inner surface side and the return conduit valve 12 so as to be movable back and forth.

Therefore, a differential pressure across the throttle portion of the feed conduit valve 17 is applied to the diaphragm 30, and the differential pressure resists the biasing force of the compression coil spring 13 and returns the conduit valve 1.
Acts in the direction of opening 2.

As a result, the return pipe valve 12 increases or decreases the flow passage area of the oil return pipe 5 so that the differential pressure across the diaphragm 30 applied to the diaphragm 30 and the biasing force of the compression coil spring 13 are balanced to increase or decrease the spray. The amount of oil returned from the nozzle 4 to the merging portion 9 is controlled so that the differential pressure across the feed line valve 17 is always kept constant.

In this embodiment, a volumetric pump 16 similar to that of the first embodiment is inserted in the oil feed pipe 2 at a position between the feed line valve 17 and the oil tank 1, The pressure inside the oil feed pipe 2 on the more downstream side is increased.

As a result, similarly to the first embodiment, since the pressure that is increased is applied to the inlet of the fuel pump 3, the volume of the air mixed with the oil is reduced, and the amount of air close to the predetermined amount is reduced. Petroleum can be constantly sent to the spray nozzle 4.

The constant differential pressure valve 50 provided in this embodiment is
The housing 5 is connected to the oil return pipe 5a on the spray nozzle 4 side.
The valve seat 52 formed in the
5 is formed by pressing the rubber packing 53. 5
A receiving seat 4 is interposed between the compression coil spring 55 and the rubber packing 53.

The present invention is not limited to the above embodiment, and means other than the positive displacement pump 16 may be used as the pressure increasing means for increasing the pressure in the oil feed pipe 2 connected to the inlet of the fuel pump 3, for example. As the fuel pump 3, a positive displacement pump or another type pump may be used instead of the compression pump.

[0037]

According to the present invention, the inlet pressure of the fuel pump is increased, the volume of air mixed in the liquid fuel is reduced, and an extra amount of liquid fuel enters the fuel pump. Even if air is mixed in the liquid fuel entering the fuel pump, the fuel pump constantly sends a quantity of liquid fuel close to a predetermined flow rate to the spray nozzle, and maintains a good combustion state with a good spray state. can do.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first embodiment.

FIG. 2 is a configuration diagram of a second embodiment.

[Explanation of symbols]

 2 Oil feed pipe 3 Fuel pump 4 Spray nozzle 5 Oil return pipe 12 Return pipe line valve 16 Positive displacement pump (pressurizing means)

Claims (1)

[Claims] 1. A fuel pump inserted in the middle of the feed pipe so as to constantly feed a fixed amount of liquid fuel from the feed pipe to a spray nozzle, and a merging portion which joins the feed pipe upstream of the fuel pump. Up to the return pipe for returning a part of the fuel from the spray nozzle, the return pipe valve for changing the flow passage area of the return pipe, and the pressurization for raising the pressure in the feed pipe connected to the inlet of the fuel pump. And a fuel supply device for a combustion device.