JP2819210B2 - Combustion equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressurized spray combustion device used as a burner for a water heater or the like.

[0002]

2. Description of the Related Art Conventionally, this type of apparatus is shown in FIG.
The fuel pressurized by the fuel pump b from the fuel supply path a is supplied to the fuel injection nozzle c as shown in FIG. 4 while being provided in a return flow path e communicating with a return hole d of the fuel injection nozzle c. By controlling the return amount from the supplied fuel according to the temperature of the controlled object by the oil proportional valve f,
The amount of fuel sprayed from the nozzle c was increased or decreased, so that the amount of combustion could be controlled steplessly.

[0003]

However, in this prior art, since the fuel is injected while swirling at a high pressure from the fuel injection nozzle c, a hollow portion h is generated in the swirl chamber g of the nozzle c, and this causes low combustion. In the mass flow region, air particularly approaches the return hole d and is trapped in the return flow passage e, and this air flows into the fuel pump b and the fuel supply passage a, and becomes uncontrollable or refuels again. By being injected from the injection nozzle c,
Are those having problems such pulsates combustion, which is 2 (a), (b), the fuel supply path a pressure P ₁ and Rita (c) - pressure down passage e P ₂ and measurement data of the discharge pressure Q _N of nozzles c - varies by - pressure air as seen, each pressure over about 2 kg / cm ² in particular the fuel supply path a range from the pressure waveform is - data Is what it is.

[0004]

In order to solve the above-mentioned drawbacks, the present invention focuses on this point. In particular, the present invention comprises a fuel supply passage provided with a fuel pump for supplying fuel to a fuel injection nozzle, and an oil proportional passage. A return passage communicating with a return hole in the fuel injection nozzle and a fuel supply passage upstream of the fuel pump, and burning by controlling an amount of fuel return by an oil proportional valve. In the control of the amount, a pressurizing means for pressurizing return fuel flowing through a return flow path from the oil proportional valve to the fuel pump is provided.

[0005]

The fuel pressurized by the drive of the fuel pump 11 is supplied to the fuel injection nozzle 1, and a part of the fuel is supplied to the oil proportional valve 1.
4 is returned via the return flow path 12 without being injected from the fuel injection nozzle 1 and the remainder is injected for combustion, and is returned by the oil proportional valve 14. By controlling the amount of fuel, the amount of combustion is controlled.

However, air is entrapped in the return flow passage 12 especially near the minimum oil amount at which the jetting pressure is reduced. Pressurized by the pressurizing means 15 and its volume is reduced to a small size, so that the fuel can be smoothly circulated in the fuel supply path 8 without becoming a large air reservoir, and the fuel injection nozzle 1 can be controlled without falling into an uncontrollable state. Since better injection is performed, good combustion can be performed without generating pulsating combustion, and the minimum oil amount, which was the neck of this type of combustion device, has been significantly reduced, so that the minimum oil amount and the maximum oil amount have been reduced. The turn-down ratio, which is the difference between the two, can be greatly increased from the conventional 1: 3 to 1: 6.5, especially when used as a burner in a water heater.
A large effect that hot water can be supplied at the set temperature instantaneously can be obtained as compared with the OFF control.

[0007]

Next, a combustion apparatus according to the present invention will be described with reference to a preferred embodiment shown in FIG . Reference numeral 1 denotes a fuel injection nozzle of a fuel return type, and a fuel return nozzle is provided at the center in a nozzle holder-2.
The nozzle 4 is formed with a distributor 4 in which a nozzle hole 3 is formed, and flows into a tip end of the nozzle holder 2 in which a spout 5 is formed and a tip of the distributor 4 from a swirl groove 6 in a peripheral wall. A swirling chamber 7 is formed in which incoming fuel is swirled and sprayed.

Reference numeral 8 denotes a fuel supply passage connecting the fuel tank 9 and the inflow port 10 of the fuel injection nozzle 1.
A fuel pump 11 for pumping fuel at a constant pressure of / cm ² is provided.

Reference numeral 12 denotes a return flow passage which communicates the return hole 3 of the distributor 4 with the fuel supply passage 8 upstream of the fuel pump 11. Check valve 13 for preventing backflow of fuel to fuel injection nozzle 1
And an oil proportional valve 14 composed of an electromagnetic coil, a valve element, a spring and the like (both not shown) are provided in this order from the fuel injection nozzle 1 side, and the return is made in accordance with the opening amount of the oil proportional valve 14. The amount is controlled to determine the amount of combustion of the fuel injection nozzle 1 so that stepless combustion can be performed according to the required amount of heat.

Reference numeral 15 denotes a return passage 12 in the fuel supply passage 8.
0.5 to 1.5 kg / c
A pressurizing means comprising a pressurizing pump for pumping fuel at a low constant pressure of m ² , and a hollow portion 1 generated by high-speed rotation of fuel in a swirl chamber 7
When the air 6 approaches the return hole 3 in the low combustion volume flow area and the air gets caught in the return flow path 12 and enters the return flow path 12, it is pressurized to reduce its volume, thereby preventing uncontrollability and pulsating combustion. Things.

Next, the operation of this embodiment will be described. If an appropriate combustion start operation is performed, the fuel pump 11 starts driving at a constant pressure, supplies the fuel in the fuel tank 9 to the fuel injection nozzle 1 through the fuel supply path 8, and controls the outlet temperature of the controlled part. The oil proportional valve 14 is controlled in accordance with the deviation between the oil temperature and the set temperature, and excess fuel is supplied through the return passage 12.
By returning the fuel to the fuel supply path 8 , the fuel injection nozzle 1 performs combustion in accordance with the required amount of heat.

Further, in a low combustion flow area where the opening of the oil proportional valve 14 is large, the air flows into the return passage 12 because the hollow portion 16 in the swirl chamber 7 approaches the return hole 3. When the air flows through the return flow passage 12 and flows into the fuel supply passage 8, the pressure of the pressurizing means 15 acts on the air, and even if the air is entangled, the air is contracted to reduce its volume. Is to be reduced as much as possible.

Next, if the above operation is expressed by a calculation formula, first, FIG.
Conventional systems to return in the air was caught between the pressure P ₂ of the - volume V ₂ is equal at the conventional and present invention systems, wherein the pressure between the oil proportional valve f, 14 a fuel pump b, 11 in both systems focusing on P _J and P _K, (conventional) P _K <(being sucked) air pressure (the present invention) P _K> atmospheric pressure (which pressurized)

[0014] Air was involved in the original of the condition - the volume V _2, in both systems in oil proportional valve f, 14
Focusing on the volumes V _J and V _K between the pump and the fuel pumps b and 11,

[0015]

(Equation 1)

From the relation of the above formula, even if the amount of the entrapped air is the same, the volume is completely different between the two systems by being pressurized by the pressurizing means 15, that is, in the present invention. In addition, the volume of the entrained air is significantly reduced as compared with the conventional system.

Accordingly, the air is kept in this contracted state until it is injected into the fuel supply passage 8 and from the fuel injection nozzle 1, so that the fuel pump 11 is operated by the air even in the low combustion flow area as in the conventional case. Malfunctions do not occur and the whole system does not become uncontrollable.Pulsating combustion can also be reliably prevented.The minimum amount of oil to be burned can be greatly reduced. 0.8l / h to 5.2l width
At / h, the turn down ratio can be set to 1: 6.5.

In addition, since the fuel containing air injected from the fuel injection nozzle 1 rapidly returns to its original volume, it is possible to reduce the atomization of spray particles and the state in which air is mixed into the spray fuel from the beginning. Therefore, there is also an effect that better combustion can be performed.

The above effects are shown in FIGS. 4 (a), (b) and (c).
As shown in FIG. 2, as is clear from the measured value of the pressure of the system of the present invention at the same place as the conventional example in FIG.
The pressure P ₁ and Rita - discharge pressure of the pressure P ₂ and the fuel spray nozzle 1 down passage 12 Q _N together, it is apparent from the fact there is no large fluctuations.

FIGS. 5 and 6 show another embodiment, in which the same components are denoted by the same reference numerals and only different points will be described. In the middle of the return flow path 12, a bypass path 17 provided with a pressurizing means 15 is connected by bypassing the fuel supply path 8,
A check valve 18 is provided on the fuel tank 9 side of the return flow passage 12 from the connection portion to the fuel supply passage 8 so as to prevent the pressure of the pressurizing means 15 from acting on the side that blocks fuel supply. The same operation can be obtained with this configuration.

FIG. 6 shows the fuel supply passage 8 from the connection of the return passage 12 to the fuel supply passage 8 to the fuel pump 11.
On the way, a bypass passage 17 having a pressurizing means 15 is connected by bypassing from a fuel supply passage 8, and a check valve 18 is provided on the fuel tank 9 side from a connection portion of the return passage 12. In this configuration, a similar effect can be obtained.

[0022]

In summary, the present invention provides a fuel injection nozzle 1
Supply path 8 with fuel pump 11 for supplying fuel to
And a return flow path 12 communicating the return hole 3 in the fuel injection nozzle 1 and the fuel supply path 8 upstream of the fuel pump 11 with an oil proportional valve 14. 1
In the control of the amount of combustion by the control of the amount of return of the fuel by the fuel pump 4, the oil proportional valve 14 to the fuel pump 11
Is provided with the pressurizing means 15 for pressurizing the return fuel flowing through the return flow path 12 up to the above, even if air is entrained in the low combustion flow area, control becomes impossible or pulsating combustion occurs. Since it is possible to surely prevent the generation of the oil, the minimum oil amount of combustion can be greatly reduced, and as a result, the turn-down ratio which is the oil amount adjustment range between the minimum oil amount and the maximum oil amount is 1: 6.6. A large value of 5 can be realized, and in this type of stepless control device, a remarkable effect such as further widening the control range and obtaining good control can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a conventional system.

FIG. 2 is a pressure waveform diagram of a conventional system, wherein (a) is a pressure P _{1 of} a fuel supply path a, (b) is a pressure P _{2 of} a return flow path e,
(C) shows the discharge pressure Q _N of the fuel injection nozzle c.

FIG. 3 is a configuration diagram of a combustion apparatus to which an embodiment of the present invention is applied.

FIG. 4 is a pressure waveform diagram of the system of the present invention, wherein (a) is the pressure P ₁ of the fuel supply passage 8, (b) is the pressure P ₂ of the return passage 12, and (c) is the pressure of the fuel injection nozzle 1. Discharge pressure Q _N.

FIG. 5 is a configuration diagram showing another embodiment.

FIG. 6 is a configuration diagram showing another embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 fuel injection nozzle 3 return hole 8 fuel supply path 11 fuel pump 12 return flow path 14 oil proportional valve 15 pressurizing means

Continuation of the front page (72) Inventor Yoshikata Uchiyama 7-7 Higashi Shinbo, Sanjo-shi, Niigata Examiner, Corona Co., Ltd. Kenichi Endo (56) References JP-A-51-95628 (JP, A) JP-A-2- 110210 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) F23N 1/00 105 F23D 11/38 F23D 11/28 F23K 5/04

Claims (1)

(57) [Claims] 1. A fuel supply path 8 having a fuel pump 11 for supplying fuel to a fuel injection nozzle 1, an oil proportional valve 14 and a return hole 3 in the fuel injection nozzle 1 and the fuel pump 11. Ritter for communicating with the upstream fuel supply passage 8
And an oil flow path 12 and a fuel
In the control of the combustion amount by controlling the return amount, a return flow path 1 from the oil proportional valve 14 to the fuel pump 11 is provided.
2. A combustion device comprising a pressurizing means 15 for pressurizing return fuel flowing through the fuel cell 2.