JP3252816B2 - Spray nozzle, fluid fuel combustion device equipped with the spray nozzle, and water heating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spray nozzle capable of obtaining good and stable combustion, a fluid fuel combustion device equipped with the spray nozzle, and a water heating device.

[0002]

2. Description of the Related Art Conventionally, as an embodiment of a fluid fuel combustion apparatus, as shown in FIG. 5, kerosene guided from a kerosene tank 70 through a strainer 71a by a head difference to an oil pipe 71 is pressurized by a pump 72 and returned. Type pressure spray nozzle 73
And sprays from the tip of the nozzle 73, returns a part of the kerosene, passes through the oil pipe 74, and goes through the flow control valve 75 to the oil pipe.
There is a configuration in which the pump 71 is returned to the upstream side of the pump 72. Also,
Such a fluid fuel combustion device is used as a water heating device. For example, a combustion device for an oil water heater is known.
In FIG. 5, reference numeral 76 denotes a check valve provided in the middle of the return oil pipe 74. With such a configuration, this fluid fuel combustion apparatus can control the spray amount over a wide range by changing the valve opening of the flow rate adjustment valve 75 provided in the return oil pipe 74 and adjusting the return oil amount, thereby changing the combustion amount. Can be.

[0003] That is, the pressure spray nozzle returned from the pump 72
The amount of kerosene supply Q _T supplied to 73 is the spray amount Q _N from the return type pressure spray nozzle 73 and the return oil pipe 74,
Because diversion on the upstream return return oil amount side Q _R, spraying amount Q _N is the amount obtained by subtracting the amount of oil Q _R returns from kerosene supply amount Q _T, changing the return oil amount Q _R Accordingly, it is possible to adjust the spray amount Q _N.

By the way, the above-mentioned return type pressure spray nozzle
As shown in FIG. 6, the front end of 73 has an inflow groove 82 formed on the outer peripheral surface on the back surface of an orifice disk 81 having a spray orifice 80 at the center and a return flow passage inside
A distributor 84 forming the 83 is joined, and a swirling chamber 85 is formed between the rear surface of the orifice disk 81 and the front surface of the distributor 84.

[0005] A part of the oil from the inflow groove 82 is returned to the return passage 83 through the swirl chamber 85, and the amount of this return is changed to control the amount of spray from the spray orifice 80.

[0006] Further, in an oil combustion device using such a return type pressure spray nozzle 73, under normal conditions, the flow rate adjustment range which is the ratio of the maximum spray amount to the minimum spray amount (turndown ratio) is 1 /. 3.5 to 1 / 3.7.

[0007] Here, the minimum spray amount means a spray amount that, if further reduced, results in an inappropriate combustion state.

[0008]

However, the above-mentioned return type pressure spray nozzle 73 still has the following problems to be solved.

That is, it is conventionally known that, in the above-mentioned return type pressure spray nozzle 73, a higher turn-down ratio provides a better combustion. On the other hand, it is known that, as shown in FIG. 6, the angle of the ejection side opening 80a of the straight tubular orifice 80 can be increased in order to obtain good combustion efficiency at the maximum fuel spray amount.

However, simply increasing the angle of the ejection side opening 80a of the spray orifice 80 in order to increase the turn-down ratio increases the minimum fuel spray amount. Therefore, the ratio cannot be increased.

On the other hand, in order to increase the turndown ratio,
When the minimum spray amount of the return type pressure spray nozzle 73 is narrowed beyond the flow rate adjustment range, the spray pattern changes, the spray angle further increases, and air is drawn into the return flow path 83 to cause pulsation of the spray, thereby causing combustion. Becomes unstable, soot and odor are generated, and an inappropriate combustion state occurs.

An object of the present invention is to provide a spray nozzle capable of solving the above-mentioned problems, and a fluid fuel combustion device and a water heating device equipped with the spray nozzle.

[0013]

According to the first aspect of the present invention, an inflow groove is formed in an outer peripheral surface and a return flow passage is formed in an inner surface of a rear surface of an orifice disk having a spray orifice in a central portion. A distributor is joined, and a swirl chamber is formed between the back of the orifice disc and the front of the distributor, and a part of the inflow fluid from the inflow groove is returned to the return flow path through the swirl chamber,
In the spray nozzle that controls the spray amount from the spray orifice by changing the reflux amount, the orifice disk has a tapered surface that gradually narrows in a curve in the spray direction at the inflow opening of the spray orifice. In addition, the present invention relates to a spray nozzle, characterized in that an oil kerf is formed on an outflow side end face of the spray orifice. Therefore,
The resistance at the time of fuel flowing into the spray orifice can be reduced, so that the flow velocity can be increased, and
The miniaturization of the fuel is promoted, and the maximum combustion amount can be increased. On the other hand, since the spray angle of the spray orifice does not need to be unnecessarily increased, the minimum combustion amount can be maintained as it is, so that the turndown ratio can be increased and good combustion can be obtained. it can.

Further, by forming an oil kerf on the outflow side end surface of the spray orifice, the amount of fuel spray is reduced, and oil dripping when the fuel spray angle is increased is prevented.

According to a second aspect of the present invention, there is provided a fluid fuel combustion apparatus having the spray nozzle.

According to a third aspect of the present invention, there is provided a water heating apparatus equipped with the above spray nozzle.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A return type pressure spray nozzle A according to the present invention will be specifically described below with reference to the accompanying drawings.

As a fluid fuel combustion device equipped with a return type pressure spray nozzle A and a water heating device, there is a combustion device for an oil water heater described in the prior art, but the overall configuration is the same as that of the conventional device. Therefore, the description here is omitted.

FIG. 1 shows the entire structure of a return type pressure spray nozzle A. The nozzle A is formed by fitting and connecting a nozzle head 12 to a front portion of a cylindrical main body 11. In addition to forming the ejection flow path 13, a main return flow path 14 is formed in the tubular main body 11. In FIG. 1, reference numeral 10 denotes a filter.

1 and 2 show the structure of the tip of the return type pressure spray nozzle A described above.

As shown in the figure, the cylindrical main body 11 has a distal end connected to a truncated conical distributor 15, and the nozzle head 12 has an orifice disk provided in a fitting mounting hole 19 provided in the center thereof. 16 is fitted.

The distributor 15 is provided with a plurality of eccentric inflow grooves 17 on a convex tapered outer peripheral surface 15a forming a front portion thereof, and has a return flow passage communicating with the main return flow path 14 at a central portion thereof. A road 18 is provided.

On the other hand, as shown in FIG. 2, the orifice disk 16 has a spray orifice 20 having a fine hole at its center.
And a concave tapered inner peripheral surface 16a corresponding to the convex tapered outer peripheral surface 15a of the distributor 15 is formed on the rear surface thereof.

As shown in FIG. 2, a convex tapered outer peripheral surface 15a of a distributor 15 is joined to the concave tapered inner peripheral surface 16a of the orifice disk 16, and an orifice D is formed on the outflow side end surface of the spray orifice. The feature is that an oil kerf is formed. Therefore, when the fuel spray amount decreases, the fuel spray angle can be increased to prevent oil dripping.

A swirl chamber 21 is formed between the concave tapered inner peripheral surface 16a of the screw 16 and the front truncated surface 15b of the distributor 15.

With this configuration, the ejection flow path 13 and the inflow groove
A part of the fuel that has flowed into the swirl chamber 21 through the return pipe 17 is returned to the return oil pipe 74 through the return flow path 18 and the main return flow path 14, and the amount of this return is changed to change the orifice for spraying the orifice disk 16 (fuel passage). The fuel can be ejected to the outside in the form of a spray while controlling the amount of spray from the (hole) 20.

The present invention is characterized in that the turn-down ratio is further improved in the structure of the return type pressure spray nozzle A described above.

That is, as shown in FIG. 2, the inflow-side opening of the spray orifice 20 of the orifice disk 16 forms a tapered surface 22 whose diameter gradually decreases in the spray direction.

Moreover, the tapered surface 22 has a curved tapered shape with an inner swelling gradually decreasing in diameter in the spray direction.

As described above, by forming the tapered surface 22 whose diameter gradually decreases in the spray direction at the inflow side opening of the spray orifice 20, the resistance when the fuel flows into the spray orifice 20 is reduced. As the flow rate increases and the flow velocity increases, miniaturization of the fuel is promoted, and the maximum combustion amount can be increased. On the other hand, since the spray angle of the spray orifice 20 does not need to be increased, the minimum combustion amount can be maintained as it is.

Accordingly, it is possible to increase the turndown ratio of the combustion device for an oil water heater equipped with the return type pressure spray nozzle A, and obtain good combustion.

Further, as shown in FIG. 2, a tapered surface 23 is similarly formed at the outlet of the orifice 20 for spraying on the outlet side of the orifice disk 16.

With the tapered surface 23, only the maximum fuel spray amount can be further increased while maintaining the minimum fuel spray amount, and the good combustion efficiency at the time of the maximum fuel spray can be further improved.

According to an experiment conducted by the present applicant, the hole diameter of the orifice 20 for spraying the orifice disk 16 varies depending on the rated spray amount, but the ejection pressure is 7 kgf / kg.
In the case of cm ² and the maximum spray rate of 3.7 l / hr, 0.28 mm was good. This hole diameter is in the range of 0.25 to 0.3 mm which is the usual fuel passage hole diameter of the spray nozzle of the oil hot water heater.

The curvature of the tapered surfaces 22 and 23 provided at the inflow opening and the outflow opening of the spray orifice 20 of the orifice disk 16 is set to 0.2 to 0.6 mm. In particular,
The best combustion was obtained when the curvature was 0.45 mm.

Further, in the present embodiment, an annular oil groove 24 is formed on the outflow side end face of the spray orifice 20 of the orifice disk 16, so that the fuel spray amount is reduced and the fuel spray angle is increased. Prevents oil drooling in case.

The tapered surfaces 23 and 24 can be easily and accurately formed by using a punch 32 as shown in FIG.

That is, first, as shown in FIG.
As a result, the spray orifice 20 is cut at the center of the orifice disk 16. In this embodiment, the drill 28
The orifice 20 for spraying is processed by using, but processing using a reamer or the like is also possible.

Next, as shown in FIG. 4, the punch body 30 has an annular concave curved surface 31 at the base periphery thereof, and the amount of projection of the punch body 30 of the punch 32 is restrained by means (not shown). The punch guide 33 and the punch guide 33 are pressed together and inserted into the spray orifice 20 of the orifice disk 16 from the outlet side, and the outlet side opening is plastically processed by the concave curved surface 31 to form an annular taper. A surface 23 is formed.
The size of the annular tapered surface 23 is determined by changing the amount of protrusion of the punch body 30.

Next, the orifice disk 16 is turned over, inserted again into the spraying orifice 20 from the inflow side opening side, and the outflow side opening is plastically worked by the concave curved surface 31 to form an annular taper. Surface 22 is formed.

[0041]

According to the first aspect of the present invention, a distributor having an inflow groove formed in the outer peripheral surface and a return flow passage formed therein is joined to the back surface of an orifice disk having a spray orifice in the center. ,And,
A swirl chamber is formed between the rear surface of the orifice disk and the front surface of the distributor, and a part of the inflow fluid from the inflow groove is returned to the return flow path through the swirl chamber. In the spray nozzle for controlling the amount of spray, the inflow side opening of the spray orifice of the orifice disk is formed with a tapered surface that gradually reduces the diameter in a curve toward the spray direction.

Accordingly, the resistance at the time of fuel flowing into the spray orifice is reduced, and the flow velocity is increased, so that miniaturization of fuel is promoted and the maximum combustion amount can be increased.
On the other hand, since the spray angle of the spray orifice does not need to be increased, the minimum combustion amount can be maintained as it is. Therefore, the turndown ratio can be increased,
Good combustion can be obtained.

Also, since the spray pressure can be reduced, noise during combustion can be reduced.

Further, by forming the oil groove on the outflow end face of the spray orifice, the amount of fuel spray is reduced, and oil dripping when the fuel spray angle is increased can be prevented.

According to the second aspect of the present invention, since the spray nozzle according to the above is mounted on the fluid fuel combustion apparatus, the apparatus can have excellent combustion performance and be quiet.

According to the third aspect of the present invention, since the spray nozzle according to the above is mounted on the water heating device, the device can have excellent combustion performance and be quiet.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional front view of a return type pressure spray nozzle according to the present invention.

FIG. 2 is an enlarged cross-sectional front view of the tip structure of the nozzle.

FIG. 3 is an explanatory view of a method of forming a spray orifice on an orifice disk.

FIG. 4 is an explanatory view of a method of forming a tapered surface on an inflow side opening and an outflow side opening of a spray orifice.

FIG. 5 is a conceptual configuration diagram of an oil combustion device having a return type pressure spray nozzle.

FIG. 6 is an enlarged sectional front view of a tip structure of a conventional return type pressure spray nozzle. FIG.

[Explanation of symbols]

 A Return type pressure spray nozzle 11 Cylindrical body 12 Nozzle head 13 Jet flow path 14 Main return flow path 15 Distributor 16 Orifice disk 17 Inlet groove 18 Return flow path 20 Spray orifice 22 Taper surface 23 Tapered surface

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-217707 (JP, A) JP-A-3-21619 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F23D 11/38 F23D 11/24-11/30

Claims (3)

(57) [Claims] 1. An orifice disk (16) having a spray orifice (20) in the center and an inflow groove (17) on the outer peripheral surface.
And a distributor (15) having a return flow path (18) formed therein, and a swirl chamber (21) is provided between the rear surface of the orifice disk (16) and the front surface of the distributor (15). A part of the inflow fluid from the inflow groove (17) is returned to the return flow path (18) through the swirl chamber (21), and the amount of the return from the spray orifice (20) is changed by changing the amount of the return. in the spray nozzle for controlling, on the inlet side opening of the spray orifice (20) of the orifice disc (16), to form a tapered surface (22) which curves reduced in diameter toward gradually spray direction, for the spray Orifice
The spray nozzle according to (20), wherein an oil kerf (24) is formed on the end face on the outflow side . 2. A spray nozzle according to claim 1.
A fluid fuel combustion device characterized by the above-mentioned. 3. A water heating apparatus comprising the spray nozzle according to claim 1 .