JPH07198127A - Two fluid spraying system - Google Patents

Abstract

PURPOSE:To provide a two fluid spraying system of which a difference between the upper limit value and lower limit value for a spraying amount of a liquid fuel to be sprayed, i.e., a turn down ratio, is large by controlling a pressure which is applied to a liquid fuel in an oil leveler in order to control the amount of a fluid fuel which is sprayed from a spray nozzle. CONSTITUTION:The revolution number of an air pump 35 is fixed, and the air pump 35 is set to feed a fixed quantity of primary air. Then, the atmospheric pressure in an oil leveler 1 is changed by a pressurization pump 5 and pressure- reducing pump 6 which are provided in the oil leveler 1. Then, e.g. the atmospheric pressure in the oil leveler 1 is raised by the pressurization pump 5, a pressure which is applied to kerosene ascends, and the kerosene flows into a discharging pipe 33, and the liquid level ascends, and the distance for a suction head drop H becomes smaller. Therefore, since the quantity of the primary air is fixed, the quantity of kerosene to be sprayed is set by the variation of the suction head drop H.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel spray system for a liquid fuel combustion burner used in a small kerosene water heater, a heater or the like, and more particularly to a controller for controlling liquid fuel supplied to a spray nozzle. Is.

[0002]

2. Description of the Related Art The following two-fluid spray system has been conventionally used for burning liquid fuel in a small kerosene water heater or a heater. FIG. 3 is a schematic diagram of a conventional two-fluid spray system. In this two-fluid atomization system,
Kerosene is supplied from the fuel tank 30 to the oil leveler 32 via the supply pipe 31, and a predetermined amount of kerosene is accumulated. The oil leveler 32 is a liquid-storing container having an open top and is divided into two chambers. One of the chambers has an inflow portion 32A into which kerosene supplied from the fuel tank 30 flows.
Are formed on the bottom of the oil leveler 32. In the other chamber, the discharge part 32B that further discharges the kerosene that has flowed in from the inflow part 32A to the discharge pipe 33 is the oil leveler 3
It is formed by a portion excluding the two inflow portions 32A.

Further, the inflow portion 32A of the oil leveler 32 has an outflow hole 32c for sending kerosene to the discharge portion 32B.
It is formed on the upper surface of 2A. And oil leveler 3
The second discharge part 32B is provided with a plug 32b for closing the outflow hole 32c formed in the inflow part 32A.
b is engaged with the float 32a via a support shaft 32d. A spray nozzle 34 for atomizing and spraying kerosene is fixed to the tip of a discharge pipe 33 for supplying kerosene discharged from the oil leveler 32. And spray nozzle 3
4 is arranged at a predetermined height from the discharge position of the oil leveler 32. From the liquid surface of kerosene at this time, the spray nozzle 34
The distance up to is called the head and is represented by H0.

On the other hand, an air pump 35 for supplying a predetermined amount of air (hereinafter referred to as primary air) for atomizing kerosene is connected to the spray nozzle 34 via an air supply pipe 36. A controller 37 is connected to the air pump 35 to change the amount of air supplied to the nozzle by changing the number of revolutions of the rotor of the air pump 35. Further, a spray nozzle 3 for spraying kerosene in a mist state.
4, a predetermined amount of air for combustion from the blower 38 (hereinafter,
A blower tube 39 is provided so as to blow the secondary air). The blower tube 39 has a cylindrical shape, a spray nozzle 34 is disposed inside the bottom surface 39a, and the tip of the spray nozzle 34 is positioned in a bottom hole 39b provided on the bottom surface. The side surface portion 39c of the blower tube 39 is hollow so that air is discharged, and a plurality of side surface holes 39d are formed on the inner side surface.

Next, the operation of the two-fluid spray system having such a configuration will be described. First, the fuel tank 30
The kerosene supplied from flows through the supply pipe 31 and flows into the oil leveler 32. At this time, kerosene first flows into the inflow portion 32A of the oil leveler 32. And the inflow part 32
The kerosene filled in A flows out to the discharge part 32B from the outflow hole 32c formed in the upper surface of the inflow part 32A by the kerosene which flows in later. Therefore, in the discharge part 32B, the discharged kerosene fills the discharge part 32B and the liquid level rises.

As the liquid level rises, the float 32a floating on the liquid level rises. At this time, the float 32a is supported by the support shaft 32d and rotates about the support shaft 32d. Then, the stopper 32b provided on the opposite side across the support shaft 32d descends as the float 32a rises, and when the liquid level rises to a predetermined position, the stopper 3 descends.
2b will block the outflow hole 32c formed in 32 A of inflow parts. Therefore, as the amount of kerosene in the discharge part 32B increases or decreases, the vertical movement of the float 32a adjusts the inflow of kerosene from the inflow part 32A to make the liquid level constant. On the other hand, the liquid level of the kerosene in the discharge pipe 33 discharged from the discharge part 32B rises as the liquid level of the kerosene in the oil leveler 32 rises, and is stabilized at the same height. Then, a negative pressure is generated by the ejection of the primary air, and kerosene is sucked up, atomized and sprayed.

The spray nozzle 34 will now be described in more detail. FIG. 4 is a view showing a cross section of the spray nozzle. The spray nozzle 34 includes a nozzle tip 41, a holder 42 and a body 51. Nozzle tip 4
No. 1 is attached to the tip of the holder 42, and a plurality of through holes 43 are provided in the outer periphery of the rear end, and the outer peripheral surface is gradually reduced in diameter toward the tip. An enlarged diameter portion 46 is formed at the tip of the nozzle tip 41, and a stepped kerosene path 48 communicating with the central hole 47 of the holder 42 and reaching the enlarged diameter portion 46 at the tip is formed at the center of the rear surface. It is provided. Expanded diameter portion 46 at the tip of the nozzle tip 41
A plurality of spray ports 50, which face the radial direction and communicate with the tip of the kerosene passage 48, are formed on the outer peripheral surface of the at an equal angular interval.

Further, the body 51 for fixing the nozzle tip 41 to the holder 42 is formed with an inflow port 52 for atomizing air opening to the outer surface in the front thereof, and a through hole 43 of the nozzle tip 41 is formed at the tip thereof. It is in communication. Further body 51
Has a passage 56 continuing from the through hole 43, and the inner peripheral surface is inclined toward the tip. A center hole 54 having a diameter larger than that of the nozzle tip 41 is provided at the center of the tip of the body 51.

In the spray nozzle 34 constructed as described above, the suction head H is kept constant, and the controller 3
A predetermined amount of primary air is supplied to the spray nozzle 34 from an air pump 35 whose rotation speed is adjusted by 7 through an air supply pipe 36. The supplied primary air is pressurized and supplied to the inflow port 52 provided in the body 51, and is ejected from the air-shaped ejection port 57 through the annular passage 55 formed inside the body 51 through the passage 56. Then, the air jetted from the air jet port 57 blows off by spraying the kerosene spray port 50 provided on the outer peripheral surface of the expanded diameter portion 46, so that the spray port 50 portion becomes a negative pressure, so that the discharge pipe 33. The kerosene inside is sucked up, atomized from the spray port 50 and sprayed.

Further, the amount of kerosene to be sprayed changes depending on the amount of primary air supplied from the air pump 35. Therefore, if the amount of flame is to be increased, the rotation speed of the air pump 35 is increased by the control means 37 to send more primary air. On the other hand, kerosene sprayed from the spray nozzle 34 is sprayed into the cylindrical blower tube 39 through the bottom hole 39b of the blower tube 39. Further, the air supplied from the blower 38 is ejected from the bottom surface hole 39b and the side surface hole 39d of the blower tube 39. Therefore, the kerosene injected from the spray nozzle 34 is blown with the secondary air for combustion supplied from the blower 38. The flow rate of the secondary air at this time is set to 100 to 200 L / min.

[0011]

In such a conventional two-fluid spray system, the liquid fuel is generated by the negative pressure generated when the primary air supplied to the spray nozzle 34 is jetted from the spray nozzle 34 as described above. The sucked up liquid fuel is atomized by the injected primary air. At this time, the spray amount of the atomized liquid fuel is adjusted based on the change in the negative pressure due to the control of the air amount of the primary air. However, such control of the primary air causes the following problems. Here, FIG. 5 is a graph showing the relationship of the liquid fuel sprayed by controlling the air amount of the primary air.

(1) Referring to FIG. 5, in the case of only the primary air shown by the solid line, the combustible spray amount is 90 ml / mi.
On the other hand, in the case of the dotted line where the secondary air is sent, it can be seen that the secondary air is greatly affected and the value is limited to a lower value. This is because the spray nozzle 34
The liquid fuel is sucked up and atomized by the negative pressure generated at the jet outlet of the liquid fuel by the secondary air, and the control is performed based on the adjustment of the primary air.
That is, even if the flow rate of the primary air is increased, if the amount is equal to or more than the predetermined amount, there is a limit to the negative pressure generated at the ejection port, so that the spray amount is also limited accordingly. As a result, the spray rate is limited to 90 ml / min when only the primary air is used.
Further, when the secondary air is sent, the flow rate of the secondary air is 1
0 to 200 L / min, which is very large with respect to the flow rate of the primary air, and raises the external air pressure, which hinders the jetting force of the primary air and reduces the negative pressure generated, resulting in a spray volume of 50 ml.
It will be limited to about / min.

(2) On the low pressure side, when only the primary air is used, the liquid fuel injected at 6.0 L / min or less is not atomized and the particles become large, so that combustion becomes impossible. On the other hand, when secondary air is sent, 7.0 L / mi
When n or less, combustion becomes impossible. As mentioned above, 2
This is because the negative pressure generated by the ejection of the primary air under the influence of the secondary air becomes smaller.

Therefore, in the conventional two-fluid atomization system,
The combustible range is limited to the spray amount range of 20 to 50 ml / min. Considering this as a turndown ratio obtained by taking the ratio of the minimum value and the maximum value, it is general for the two-fluid spray system having the above configuration to obtain a turndown ratio of about 1: 2.5 to 5. Wider turndown ratios are desired for spray systems. When it is used as a heater or a water heater, it is inevitable that the amount of spray will increase because a strong flame is preferred, but it is also necessary to spray a small amount of liquid fuel, such as to keep hot water. Therefore, it is necessary to appropriately spray a small amount of liquid fuel from many liquid fuels. In this respect, in the case of providing the one with a strong flame, the conventional one is uneconomical because it is necessary to spray more liquid fuel than necessary for keeping heat.

Therefore, in the two-fluid spray system of the present invention, the upper limit value to the lower limit value of the spray amount of the liquid fuel to be sprayed,
That is, the purpose is to provide a large turndown ratio.

[0016]

A two-fluid spraying system of the present invention is an oil leveler for discharging liquid fuel from a fuel tank into a discharge pipe, a spray nozzle attached to the tip of the discharge pipe, and a liquid fuel in the discharge pipe. In a two-fluid spray system comprising an air pump for supplying primary air to a spray nozzle for sucking and atomizing air and a blower for injecting secondary air for combustion to sprayed liquid fuel. ,
In order to control the amount of liquid fuel sprayed by the spray nozzle, a pressure control device for controlling the pressure applied to the liquid fuel in the oil leveler is provided. Further, in the two-fluid spray system of the present invention, the pressure control device is composed of a pressure pump and a pressure reduction pump connected to the oil leveler. Further, in the two-fluid spray system of the present invention, the pressure control device includes a pressure pump connected to the oil leveler and an orifice.

[0017]

The two-fluid spraying system of the present invention having the above-mentioned structure operates as follows. Liquid fuel filling the fuel tank is supplied to the oil leveler via the supply pipe. A predetermined amount of liquid fuel is accumulated in the oil leveler. Then, by the pressure control device provided in the oil leveler, the pressure is applied to the liquid fuel accumulated in the oil leveler, and the liquid level of the liquid fuel in the discharge pipe toward the spray nozzle changes with the pressure change. To do. On the other hand, a predetermined amount of air is supplied to the spray nozzle from an air pump via an air supply pipe. When a predetermined amount of air supplied from the air pump blows out from the spray nozzle to the outside, it produces a negative pressure at the spray port, but because the blower sends a predetermined amount of secondary air for combustion, it is affected by this. A constant negative pressure is generated at the spray port. Therefore, the amount of liquid fuel sprayed is controlled by changing the liquid level of the liquid fuel in the discharge pipe toward the spray nozzle with respect to the negative pressure generated at the spray port.

Further, in the two-fluid spray system of the present invention,
The amount of liquid fuel sprayed is controlled by adjusting the pressure applied to the liquid fuel in the oil leveler with a pressurizing pump and a depressurizing pump to change the liquid level of the liquid fuel in the discharge pipe toward the spray nozzle. Further, in the two-fluid spraying system of the present invention, the pressure applied to the liquid fuel in the oil leveler is adjusted by supplying air into the oil leveler with a pressurizing pump for a certain amount of air in the oil leveler injected from the orifice. By changing the liquid level of the liquid fuel in the discharge pipe toward the spray nozzle, the amount of the liquid fuel sprayed is controlled.

[0019]

EXAMPLES Examples in which the two-fluid spray system of the present invention is embodied will be described below. FIG. 1 is a diagram showing a two-fluid spray system according to a first embodiment of the present invention. This two-fluid spraying system has a part in common with the above-mentioned conventional system, and such a configuration will be described with the same reference numerals in the drawings. First, in the two-fluid spray system of the present embodiment, the fuel tank 30 is connected to the supply pipe 3 as in the conventional system.
An oil leveler 1 is connected via 1 and the oil leveler 1 is further connected via a discharge pipe 33 to a spray nozzle 34. The oil leveler 1 is composed of a closed container, and the inside thereof is divided into two chambers as in the conventional case. One of the chambers is a supply pipe 31 at the bottom of the oil leveler 1.
Are connected to form an inflow portion 1A into which kerosene flows. This inflow portion 1A is formed only in a part of the bottom of the container, and the other space of the container of the oil leveler 1 is provided with the discharge pipe 3
The discharge part 1B to which 3 is connected is configured. Inside the container of the oil leveler 1 that constitutes the discharge part 1B, a plug 3 for closing the outflow hole 1a formed in the inflow part 1A is provided, and the plug 3 is attached to the float 2 via the support shaft 4 via a support shaft 4. It is worn. Further, the oil leveler 1 is provided with a pressurizing pump 5 and a depressurizing pump 6 that increase and decrease the air pressure inside the oil leveler 1.

An air pump 35 for supplying primary air is connected to the spray nozzle 34 fixedly provided at the tip of the discharge pipe 33 via an air supply pipe 36. A control device 37 for changing the amount of air supplied to the spray nozzle 34 is connected to the air pump 35. However, in the present embodiment, the air amount of the primary air by the air pump 35 is fixed by the controller 37 to be constant. The air amount of the primary air is 12 L / min corresponding to the maximum spray amount as shown in FIG. Further, as in the conventional case, the spray nozzle 34 for spraying kerosene in a mist state is provided with a blower tube 39 so as to wrap the secondary air from the blower 38 for supplying air to a predetermined position. The blower tube 39 has a cylindrical shape, a spray nozzle 34 is disposed inside the bottom surface portion 39a, and the tip of the spray nozzle 34 is located in a bottom surface hole 39b provided in the bottom surface. The side surface portion 39c of the blower tube 39 is hollow so that air is discharged, and a plurality of side surface holes 39d are formed on the inner side surface.

The two-fluid spray system of this embodiment having such a structure operates as follows. First, the fuel tank 3
Kerosene that satisfies 0 is supplied to the oil leveler 1 via the supply pipe 31, and the kerosene is accumulated in the oil leveler 1. At this time, the float 2 rises as the amount of kerosene increases, and conversely the plug 3 descends via the support shaft 4 to close the outflow hole 1a when the amount of kerosene reaches a predetermined amount. On the other hand, the spray nozzle 34
A predetermined amount of primary air is supplied from the air pump 35 through the air supply pipe 36. The primary air supplied from the air pump 35 blows out from the spray nozzle 34, but at this time, a negative pressure is generated at the spray port of the spray nozzle 34. Therefore, the kerosene is sucked up by the distance of the suction head H and, at the same time, is sprayed by the primary air to the outside of the spray nozzle 34.

By the way, the kerosene is sprayed from the spray nozzle 34 in this way, but in the prior art, the air amount of the primary air is changed by changing the rotation speed of the air pump as described above, and the spray amount is changed. Although it was adjusted, in the present embodiment, the rotation speed of the air pump 35 is fixed as described above, and it is set to send a fixed amount of primary air. Then, the pressure in the oil leveler 1 is changed by the pressure pump 5 and the pressure reducing pump 6 provided in the oil leveler 1. By doing so, for example, if the pressure in the oil leveler 1 is raised by the pressurizing pump 5, the pressure applied to the kerosene rises, and the kerosene flows into the discharge pipe 33, whereby the liquid level rises and the suction head H rises. The distance becomes smaller. On the contrary, if the pressure inside the oil leveler 1 is reduced by the decompression pump 6, the kerosene in the discharge pipe 33 flows backward into the oil leveler 1 to lower the liquid level and the distance of the suction head H increases. Therefore, since the amount of primary air is constant as described above, the amount of kerosene to be sprayed is set by the fluctuation of the suction head H. Furthermore, secondary air is supplied from the blower 38 to the sprayed kerosene, and the kerosene sprayed from the spray nozzle 34 is diffused by the primary air.

Here, the measurement result of the spray amount with respect to the pressure in the oil leveler 1 when the two-fluid spraying device of the present embodiment having the above-mentioned configuration is used will be described with reference to FIG. As can be seen from the graph, the spray amount increases in proportion to the increase in the atmospheric pressure inside the oil leveler 1. This is because the pressure of the primary air is constant and the influence of the secondary air does not change. In addition, in the two-fluid spray system of the present embodiment, the spray rate is 10 ml / min to 100 ml / min.
It was found that combustion is possible within the above range. this is,
This is because the suction head H is changed so as to be sprayed in a combustible state in response to a predetermined negative pressure generated by the primary air that is affected by the secondary air. That is, while the air amount of the primary air that generates the negative pressure has been used as a variable in the related art, the negative pressure is made constant and the gas pressure in the oil leveler that determines the suction head H is used as a variable in this embodiment.

As described above, in the two-fluid spray system of this embodiment, the spray amount is controlled by changing the atmospheric pressure in the oil leveler 1 by the pressurizing pump 5 and the depressurizing pump 6 and adjusting the suction head. Since the amount increases or decreases in proportion to the atmospheric pressure in the oil leveler 1, it becomes possible to accurately control the spray amount. Similarly, since the spray amount is controlled by changing the atmospheric pressure in the oil leveler 1 by the pressurizing pump 5 and the depressurizing pump 6, it is not affected by the secondary air. Therefore, compared with the conventional two-fluid spray system. And the turndown ratio has been greatly increased.

Next, a second embodiment of the two-fluid spray system according to the present invention will be described. FIG. 2 is a diagram showing a two-fluid spray system of the second embodiment. The same components as those in the first embodiment are designated by the same reference numerals. The difference between the two-fluid spray system of this embodiment and that of the first embodiment is that
Oil leveler 1, pressurizing pump 15, orifice 1
6 is the point formed. Therefore, in the two-fluid spray system having such a configuration, a certain amount of air flows out from the orifice 16 in response to the supply of air by the pressurizing pump 15. Therefore, by adjusting the amount of air supplied into the oil leveler 1 by the pressurizing pump 15 with respect to the amount of air flowing out from the orifice 16 to the outside of the oil leveler 1, the air pressure inside the oil leveler 1 is set, and the suction head H1 Is determined. Then, as in the first embodiment, the kerosene is sprayed from the spray nozzle 34 by a fixed amount of primary air.

In the two-fluid spray system of this embodiment, the spray amount is controlled by changing the atmospheric pressure in the oil leveler 1 by means of the pressurizing pump 15 and the orifice 16. Therefore, as in the case of the first embodiment, the spraying is performed. Since the amount increases / decreases in proportion to the atmospheric pressure in the oil leveler 1, it becomes possible to accurately control the spray amount. Further, since it is not affected by the secondary air, the turndown ratio is greatly increased as compared with the conventional two-fluid spray system. Furthermore, the structure is simplified by using the orifice 16 to reduce the pressure inside the oil leveler 1, and the pressure is adjusted only by the pressurizing pump 15, which facilitates the control.

Although the embodiment of the two-fluid spray system of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the invention. For example, in the above-described embodiment, the pressure inside the oil leveler is adjusted by using the pressure pump and the pressure reducing pump or the orifice as the pressure control device, but the air from the air pump may be adjusted by the accumulator. Good. Further, for example, the spray nozzle is shown in FIG. 4, but it is not limited to this as long as the liquid fuel is sprayed by the negative pressure of the primary air.

[0028]

As is apparent from the above description, in the two-fluid spray system of the present invention, the pressure control device that sets the pressure applied to the liquid fuel in the oil leveler raises and lowers the suction head to determine the spray amount. Therefore, it has become possible to provide an upper limit value to a lower limit value of the spray amount of the liquid fuel to be sprayed, that is, a large turndown ratio.

[Brief description of drawings]

FIG. 1 is a diagram showing a two-fluid spray system according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a two-fluid spray system according to a second embodiment of the present invention.

FIG. 3 is a diagram showing a conventional two-fluid spray system.

FIG. 4 is a view showing a cross section of a spray nozzle.

FIG. 5 is a graph showing the relationship between spray amounts in a conventional two-fluid spray system.

FIG. 6 is a graph showing a relationship between spray amounts in the two-fluid spray system of the present invention.

[Explanation of symbols]

 1 Oil Leveler 5 Pressure Pump 6 Decompression Pump 15 Pressure Pump 16 Orifice 30 Fuel Tank 31 Supply Pipe 33 Discharge Pipe 34 Spray Nozzle 35 Air Pump 36 Air Supply Pipe 37 Controller 38 Blower 39 Blower Tube

Claims (3)

[Claims] 1. An oil leveler for discharging liquid fuel from a fuel tank into a discharge pipe, a spray nozzle attached to the tip of the discharge pipe, and a spray nozzle for sucking and atomizing the liquid fuel in the discharge pipe. In a two-fluid atomization system including an air pump for supplying secondary air and a blower for injecting secondary air for combustion to atomized liquid fuel, the amount of liquid fuel atomized by the atomizing nozzle is adjusted. A two-fluid atomization system comprising a pressure control device for controlling the pressure applied to the liquid fuel in the oil leveler for controlling. 2. The two-fluid spray system according to claim 1, wherein the pressure control device includes a pressure pump and a decompression pump connected to the oil leveler. 3. The two-fluid spray system according to claim 1, wherein the pressure control device includes a pressure pump connected to the oil leveler and an orifice.