JP2003262330A - Fuel flow control device for oil combustor burner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent incomplete combustion by preventing an increase in spray quantity from a return type pressure spray nozzle even when a discharge quantity drops owing to a secular cause in an electromagnetic pump in an advance line, in a fuel flow control device for an oil combustor burner using a return type pressure spray nozzle. <P>SOLUTION: The fuel flow control device for an oil combustor burner using the return type pressure spray nozzle has in a return line a flow regulating valve driven by valve opening time control based on a duty ratio for varying a pulse width. A spray quantity from the spray nozzle can be thus prevented from increasing to prevent incomplete combustion. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel flow rate control device for an oil burner burner used in an oil burning water heater and the like.

[0002]

2. Description of the Related Art A fuel flow rate control device for a burner for an oil combustor is known as disclosed in Japanese Patent No. 2689066, in which a fuel introduced from a fuel tank through an outward path is pressurized by a pump, and a return type is used. It is supplied to the pressurized spray nozzle, but a return path is connected from the vicinity of the nozzle, a proportional control valve (flow rate adjusting valve) is provided in this return path, and its end is connected to the suction side of the pump. It is what

Such a conventional example is schematically shown in FIG. 3, and the spray amount (Qn) from the return type pressure spray nozzle is returned by controlling the current value of the proportional control valve (PRV). Low pressure (PL) for in-road pressure (P ₂ )
To high pressure (PH), the operating characteristics of which are shown in FIG. 4 between b and c.

[0004]

However, when the discharge pressure of the pump is lowered from 0.98 MPa to 0.882 MPa as shown in FIG. 4 due to aged deterioration, the operating characteristics are b'and c. ′, The injection amount (Qn) changes from QnH′-QnH to QnL′-Qn.
Increase by L. This is due to the characteristic of the proportional control valve (PRV), that is, the valve that acts to maintain the pressure, even though the discharge pressure of the pump has decreased, so that the return path internal pressure (P ₂ ) hardly changes. It is in.

[0005] If specifically, in the proportional control valve schematically illustrated in FIG. 5, the product of the return path pressure, the pressure receiving area of the proportional control valve, i.e. ^{_{P 2 × π · ds 2/}} 4 ( pressure force ) Is the electromagnetic force Fm
The valve is opened when the force obtained by adding g and the spring force Fspr is exceeded, and the valve is closed when the pressure in the return passage (P ₂ ) decreases due to the valve opening. By repeating this, the pressure in the return passage (P ₂ ) is controlled. There is.

Since the parameters of the valve opening pressure are the electromagnetic force Fmg and the spring force Fspr of the coil driven by the constant current, as long as the pump pressure (P ₁ ) exceeds the valve opening pressure, the return path The pressure (P ₂ ) is already constant. Therefore,
Even if the discharge pressure of the pump decreased, the return passage internal pressure (P ₂ ) hardly changed, and the deterioration of the air-fuel ratio resulted in incomplete fuel, causing problems such as soot clogging.

Therefore, an object of the present invention is to prevent incomplete combustion without increasing the spray amount of fuel even if the discharge pressure is lowered due to aged deterioration of the pump.

[0008]

A fuel flow rate control apparatus for a burner for an oil combustor according to the present invention pressurizes fuel introduced from a fuel tank through an outward path with a pump and supplies the fuel to a return type pressure spray nozzle. A fuel flow rate control device for a burner for an oil combustor, in which a part of fuel is sprayed from the return type pressure spray nozzle and is returned from the return path to the suction side of the pump on the outward path through a flow rate adjusting valve The flow rate adjusting valve includes a valve seat having a through hole in a flow path serving as a return path,
A valve body seated on the valve seat and a plunger for opening and closing the valve body are arranged. The plunger is supported by opposing springs and a desired pulse is applied to an electromagnetic coil to duty the valve body. It is to control the valve opening time by (Claim 1).

Therefore, the flow rate control valve controls the duty ratio of the valve body by the applied pulse, that is, the valve opening time control, and the pressure in the return passage decreases in accordance with the decrease in the discharge pressure of the pump. The amount does not change, and the generation of incomplete fuel due to excess fuel can be prevented.

The valve body is made of fluororesin (claim 2). Therefore, the fitting with the valve seat is improved, and problems due to misalignment can be eliminated.

Further, an orifice and an accumulator are provided in the flow passage of the flow rate adjusting valve (claim 3). As a result, the pulsation due to the vibration (reciprocation) of the electromagnetic plunger and the valve element due to the pulse can be smoothed, and the combustion noise of the fuel can be reduced.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

1 and 2, there is shown a fuel flow rate control device 1 for a burner for an oil combustor, which is roughly classified into an oil tank 2,
It is composed of a flow rate adjusting valve 3, an electromagnetic pump 4 and a return type pressure spray nozzle 5, and is connected by piping as shown in the figure.

The flow rate adjusting valve 3 has a valve body 7 arranged at the lowest position, a through hole 8 in the lateral direction, a joint 9 having a male screw engraved at one end, and an insertable joint 10 at the other end. In addition, it has a through hole 11 orthogonal to the through hole 8. An adjusting screw 12 is screwed into the through hole 11.
The joint 9 is connected to the oil tank 2 via a pipe 17.

An adjusting portion 13 for adjusting the flow rate is arranged above the valve main body 7. The structure has an electromagnetic coil 14 wound around a bobbin 16, and a guide case 18 is arranged at the center of the bobbin 16. A magnetic rod 19 is arranged at the lower end of the guide case 18. The magnetic rod 19 has a through hole 20 in the axial direction, and a loosely inserted rod 21 is arranged in the through hole 20. The rod 21 abuts on the adjusting screw 12 at the lower end and the lower end of a lower spring 26 described below at the upper end. Is in contact with.

An electromagnetic plunger 24 is slidably arranged above the magnetic rod 19 in the guide case 18. That is, the electromagnetic plunger 24 is supported by the upper spring 25 and the lower spring 26. This electromagnetic plunger 2
No. 4 has a through hole 27 in the axial direction, and a valve body 29 made of fluororesin called Teflon (trademark) is attached above. The valve element 29 is in a state of being seated on a valve seat 30 which will be described below when there is no energization.

The valve seat 30 is attached to the upper end of the guide case 18, has a through hole 31 in the axial direction, and has an orifice 32 in the through hole 31.

The cover 34 has a through hole 35 in the axial direction,
The guide case 18 is disposed above the adjusting unit 13 that adjusts the flow rate, and is inserted into the through hole 35. Further, an accumulator 36 is connected in the through hole 35, a check valve 38 is provided, and a joint 37 with a screw is attached to the upper end thereof. The through hole 39 of the joint 37 is connected to the return type spray nozzle 5 via a pipe 38.

In the electromagnetic pump 4, the valve body 40 is arranged at the lowermost part, and a through hole 41 and a joint (suction port) 42 which is inserted at the end are formed in the lateral direction. The connector 43 inserted into the joint 10 of the flow rate adjusting valve 3 is inserted into the joint 42, and communicates with the through hole 8 and the through hole 41 through the through hole 44 of the connector 43.

An electromagnetic coil 48 wound around a bobbin 47 for driving the electromagnetic plunger 50 is provided above the valve body 40. A guide case 49 is arranged in the central axis direction of the bobbin 47, and the lower end of the guide case 49 is inserted into the valve body 40.

An electromagnetic plunger 50 is slidably supported in the guide case 49 while being supported by an upper spring 52 and a lower spring 53. A through hole 54 is formed in the electromagnetic plunger 50 in the axial direction, and a piston 55 is connected to the lower end of the through hole 54. That is, the piston 55 follows the electromagnetic plunger 50.

The piston 55 is inserted into a cylinder 56 supported by the valve body 40, the volume of the pump chamber 57 is changed by the reciprocating movement of the piston 55, and the pump action is achieved by the cooperation of the suction valve and the discharge valve. The fuel that has been pressurized is supplied into the guide case 49.

The magnetic rod 59 corresponds to the guide case 49.
Is provided above and has a through hole 60 in the central axis direction. At the upper end of the magnetic rod 59, a solenoid valve movable chamber 62 composed of a discharge joint 61 inserted into the bobbin 47.
Are formed.

An electromagnetic valve 63 is housed in the electromagnetic valve movable chamber 62, and a spring 64 is applied when a pulse is applied to the electromagnetic coil 48.
It is opened against and closed when shut off. A discharge through hole 65 is formed in the discharge joint 61 and is connected to the return type pressure spray nozzle 5 through a pipe 66.

The pipe 17, the through hole 8 of the valve body 7, the through hole 44 of the connector 43, the through hole 41 of the valve body 40, the guide case 49, the through hole 60 of the magnetic rod 59, the solenoid valve movable chamber 62, and the discharge. An outward path to the return type pressure spray nozzle 5 is formed by the through hole 65 and the pipe 66, and the pipe 38, the through hole 39 of the joint 37, the through hole 35 of the cover 34, the guide case 18, the through hole 20 of the magnetic rod 19 and A return path from the return type pressure spray nozzle 5 is formed in the through hole 11 of the valve body 7, and the through hole 11 is connected to the through hole 8 which is an outward path of communication with the suction port 42 of the electromagnetic pump 4.

In the above-mentioned configuration, the fuel flow rate control device 1
In driving, a predetermined drive pulse current is applied to the electromagnetic pump 4 to obtain a constant output, but the flow rate adjusting valve 3 is applied with a periodic high frequency (for example, 50 HZ) pulse current (PWM) whose pulse width is changed. It That is, the electromagnetic pump 4 obtains a constant output, but the flow rate adjusting valve 3 is controlled by the duty ratio for the valve opening time, and the valve opening time determines the amount returned through the return path. This is different from the structure that operates by pressure balance before and after the valve, such as the proportional control valve shown in the conventional example.

Therefore, even if the discharge capacity (discharge amount) of the electromagnetic pump deteriorates due to changes over time, the flow rate adjusting valve controls the valve opening time by the duty ratio, so the return amount is determined by the valve opening time. As explained in FIG. 4, the spray amount Qn comes to shift from b to b ″ and from c to c ″.
The increase in the spray amount does not occur, the air-fuel ratio does not change, and the occurrence of incomplete combustion can be prevented.

Since the flow rate adjusting valve 3 serving as the return path is provided with the orifice 32 and the accumulator 36, the electromagnetic plunger 24 and the valve element 29 reciprocate (vibrate).
The pulsation due to is smoothed, and the combustion noise of fuel can be reduced.

In the flow rate adjusting valve 3, the electromagnetic plunger 24 is supported by the upper and lower springs 25 and 26, and the amount of flexure thereof is adjusted by the adjusting screw 12. However, both springs can be appropriately selected. For example, the adjusting screw 12 may be deleted.

[0030]

As described above, according to the present invention, even if the capacity of the electromagnetic pump for supplying the return type pressure spray nozzle is lowered, the control system of the flow rate adjusting valve for controlling the return amount has a pulse width. Since the valve opening time control is performed by the modulating duty ratio, the amount of spray does not increase and incomplete combustion can be prevented. Further, by providing the accumulator and the orifice in the through hole of the flow rate adjusting valve forming the return path, the pulsation can be smoothed and the combustion noise can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view of a fuel flow rate control device for a burner for an oil combustor according to the present invention.

FIG. 2 is a front view with a partial cross section of the above flow rate adjusting valve.

FIG. 3 is a configuration diagram of a fuel flow rate control device for a burner for an oil combustor, which is an example having a proportional control valve in a return path as a conventional example.

FIG. 4 is a characteristic diagram of the same as above, showing that the electromagnetic pump has a capacity of 0.9.
It is a figure which shows the relationship between the amount of sprays in 8 MPa and 0.882 MPa, and the pressure in a return path.

5 is a configuration diagram of a proportional control valve (PRV) shown in FIG.

[Explanation of symbols]

1 Fuel flow control device for burner for oil combustor 3 Flow control valve 4 Electromagnetic pump 5 Return type pressure spray nozzle 7 valve body 14 Electromagnetic coil 16 bobbins 18 guide case 24 Electromagnetic Plunger 29 valve 32 orifice 36 Accumulator 40 valve body 50 electromagnetic plunger 55 pistons 56 cylinders 59 Magnetic Rod 63 Solenoid valve

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Atsushi Nomura             5-16 Chiyoda, Sakado City, Saitama Japan             Control Industry Co., Ltd. F-term (reference) 3H106 DA07 DA13 DA23 DB02 DB12                       DB23 DB32 DC02 DC17 DD03                       EE48 FA04 FB24 GB11 KK13                       KK16                 3K068 AA11 BB01 BB14 BB16 BB18                       BB21 CA16 CA28 EA02

Claims (3)

[Claims] 1. The fuel introduced from the fuel tank through the outward path is pressurized by a pump, supplied to a return type pressure spray nozzle, sprayed from the return type pressure spray nozzle, and a part of the fuel is returned to the return path. In the fuel flow rate control device for a burner for an oil combustor, which is returned to the suction side of the pump on the outward path via a flow rate adjustment valve, the flow rate adjustment valve is a valve having a through hole in a flow path serving as a return path. A seat, a valve body seated on the valve seat, and a plunger for opening and closing the valve body. The plunger is supported by opposite springs and a desired pulse is applied to an electromagnetic coil to apply the desired pulse to the valve. A fuel flow rate control device for a burner for an oil combustor, characterized in that the valve opening time is controlled by the duty ratio of the body. 2. The fuel flow rate control device for a burner for an oil combustor according to claim 1, wherein the valve body is made of fluororesin. 3. The fuel flow rate control device for a burner for an oil combustor according to claim 1, wherein an orifice and an accumulator are provided in the flow path of the flow rate control valve.