JPH07217870A - Fuel supplying device for combustion device - Google Patents

Abstract

PURPOSE:To provide a fuel supplying device for a combustion device, which is capable of controlling the flow rate of fuel, burnt through a spray nozzle, directly and correctly, never-sucking air into a returning pipe from the spray nozzle and capable of effecting stabilized combustion at all times. CONSTITUTION:A fuel supplying device is provided with a fuel pump 3, interposed on the way of a sending pipe 2 so as to send a given amount of liquid fuel into a spray nozzle 4 at all times, a returning pipe 5 for returning a part of fuel from the spray nozzle 4 to a joining part 9, joining with the sending pipe 2 at the upstream side of the fuel pump 3, and a returning pipeline valve 12 for changing the flow passage area of the returning pipe 5. Further, choking units 17, 19, choking the flow passage area of the sending pipe 2 at the upstream side of the choking units 17, 19, a differential pressure operating means 30, controlling the operation of a returning pipeline valve 12 by a pressure difference between the upstream side of the choking units 17, 19 and the downstream side of the same, and a constant pressure difference valve 50, maintaining a pressure in the returning pipe 5a of the spray nozzle 4 so as to be higher by a give value compared with a pressure in the returning pipe 5b of the returning pipeline valve 12, are provided.

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 constantly supplies a fixed amount of oil, which is introduced from an oil tank to an oil feed pipe, to a spray nozzle by means of a fuel pump, and supplies the oil feed pipe upstream of the fuel pump. The combustion amount is adjusted by changing the amount of oil returned from the spray nozzle via the oil return pipe.

In order to accurately control the amount of combustion,
A return pipe valve for changing the flow passage area of the oil return pipe, and a throttle portion for narrowing the flow passage area of the oil feed pipe upstream of the joining portion (the joining portion of the oil feed pipe and the oil return pipe) are provided. Improvements have been made so that the operation of the return line valve is controlled by the pressure difference between the oil feed pipes on the upstream side and the downstream side of the throttle portion (JP-A-5-60).
320).

According to such an improved construction, the flow rate of petroleum used for combustion by the spray nozzle is directly determined from the flow passage area of the throttle portion of the oil feed pipe and the differential pressure across the oil feed pipe, Since the return flow rate from the spray nozzle only changes accordingly, it is possible to directly and accurately control the flow rate of petroleum used for combustion.

[0005]

However, in such a conventional apparatus, when the throttle portion of the oil feed pipe is extremely narrowed to reduce the amount of combustion, the return line valve is almost fully opened. Then, the pressure in the oil return pipe becomes almost the same as the atmospheric pressure.

Since the pressure in the oil return pipe fluctuates due to pulsation or the like, the pressure may be lower than atmospheric pressure. In particular, when the oil tank is installed at a low position, the pressure inside the oil return pipe tends to fall below atmospheric pressure.

However, when the pressure in the oil return pipe becomes lower than atmospheric pressure, air is sucked into the spray nozzle from the tip, and air is mixed with the oil returning to the oil return pipe. Then, the air mixed with the oil in the oil return pipe is sucked into the fuel pump.

As a result, the compression capacity of the fuel pump is extremely reduced and the pressure on the high pressure side is reduced. As a result, the flow rate of the spray from the spray nozzle is drastically reduced, and the air-fuel ratio falls below the limit value, resulting in misfire. It may happen.

Therefore, the present invention can directly and accurately control the flow rate of the fuel used for combustion in the spray nozzle,
Moreover, air is not sucked into the return pipe from the spray nozzle,
An object of the present invention is to provide a fuel supply device for a combustion device that can always perform stable combustion.

[0010]

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. A return pipe valve for reducing the flow passage area of the feed pipe on the upstream side of the merging portion, and the return pressure by operating the differential pressure between the feed pipe on the upstream side and the downstream side of the throttle portion. A differential pressure operating means for controlling the operation of the conduit valve, and a constant differential pressure valve for maintaining the pressure in the return pipe of the spray nozzle portion at a constant pressure higher than the pressure in the return pipe of the return conduit valve portion. It is characterized by being provided.

[0011]

[Function] The flow rate of fuel consumed for combustion in the spray nozzle is
It is determined by the flow passage area of the throttle portion of the feed pipe formed on the upstream side of the confluence portion and the pressure difference between the upstream and downstream sides of the throttle pipe.

Further, the pressure in the return pipe of the spray nozzle portion is always kept higher by a constant pressure than the pressure in the return pipe of the return conduit valve portion by the constant differential pressure valve. Therefore, even if the pressure in the return pipe of the return pipe valve portion becomes equal to or lower than the atmospheric pressure,
The pressure in the return pipe on the spray nozzle side can be maintained higher than atmospheric pressure, and air is not sucked into the return pipe from the tip of the spray nozzle.

[0013]

Embodiments will be described with reference to the drawings. FIG. 1 shows an embodiment of the present invention, in which a fuel pump 3 inserted in the middle of an oil feed pipe 2 which communicates an oil tank 1 and a spray nozzle 4 causes the oil in the oil tank 1 to feed oil. A constant amount is always sent to the spray nozzle 4 through the pipe 2. The oil tank 1 is installed at a lower position than the device of the embodiment.

A part of the petroleum oil sprayed in the tip of the spray nozzle 4 passes through the oil return pipe 5 and the oil feed pipe 2 from the confluence portion 9 where the oil feed pipe 2 is joined 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.

FIG. 2 shows the structure of the spray nozzle 4,
The oil sent from the oil feed pipe 2 to the spray nozzle 4 passes through the feed passage 41 and the narrow conical slit portion 42 in which a fine spiral groove (not shown) is formed, so that the spray nozzle It is sprayed on the spraying part 43 in the 4 tip.

A part of the sprayed oil is sprayed from the tip opening 44 of the spray nozzle 4 to the combustion section, and the rest is returned from the return passage 45 through the oil return pipe 5 as described above. It is returned to the confluence section 9.

Returning to FIG. 1, the oil return pipe 5 has a ball-shaped return pipe valve 12 for changing the flow passage area of the oil return pipe 5.
Is urged by the compression coil spring 13 toward the valve seat 11 formed immediately before the confluence portion 9 and arranged. 14
Is a coil spring receiver, and 15 is a nut for adjusting the spring force of the compression coil spring 13.

In addition, a ball-shaped feed pipe valve 17 for changing the flow passage area of the oil feed pipe 2 is arranged on the oil feed pipe 2 upstream of the confluence portion 9 and fixed to the tip of the rod 18. Has been done.

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 and accurately narrowed. Reference numerals 25 and 26 are O-rings for sealing and their receiving plates.

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 feed line valve 17 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.

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 urging force of the compression coil spring 13 and the return 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 applied to the diaphragm 30 and the urging force of the compression coil spring 13 are balanced, and the return pipe valve 12 joins from the spray nozzle 4. The amount of oil returned to section 9 is controlled so that the differential pressure across the feed line valve 17 is always kept constant.

According to the apparatus of the embodiment thus constructed, the flow rate of the oil flowing through the feed line valve 17 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. It is itself.

The flow rate of petroleum used for combustion is determined only by the flow passage area of the feed pipe valve 17. Therefore, by controlling the flow passage area of the feed pipe valve 17 by the motor 21, the flow rate of the oil used for combustion is directly and accurately controlled, and the oil flow returned to the oil return pipe 5 is followed. Flow rate changes.

In the middle of the oil return pipe 5, a constant pressure for maintaining 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 line valve 12 side. The differential pressure valve 50 is inserted.

The constant differential pressure valve 50 is connected to the oil return pipe 5a on the side of the spray nozzle 4 and has a valve seat 52 formed in the housing 51.
It is formed by pressing 3. The housing 51 of the constant differential pressure valve may be formed integrally with the body 10 on the return conduit valve 12 side.

Reference numeral 54 designates a receiving seat interposed between the compression coil spring 55 and the rubber packing 53, and 56 communicates with the oil return pipe 5b on the return pipe line valve 12 side and the housing 51.
Is a connection lid that is airtightly fixed to the other end of the compression coil spring 55 and receives the other end of the compression coil spring 55.

In the constant differential pressure valve 50 thus constructed, the magnitude of the differential pressure to be kept constant can be arbitrarily selected by changing the setting of the spring load of the compression coil spring 55.

The differential pressure is, for example, 0.1 MPa (≈1 kg
/ Cm ² G), but according to various conditions of the device,
For example, it is set to an optimum value within the range of 0.01 to 0.3 MPa.

The constant differential pressure valve 50 also functions as a check valve for preventing the oil in the oil return pipe 5 from flowing back to the spray nozzle 4 side, and if the spring load of the compression coil spring 55 is made extremely small. , Will only act as a check valve.

As described above, by providing the constant differential pressure valve 50 in the middle of the oil return pipe 5, even if the pressure in the oil return pipe 5b of the return pipe valve 12 portion becomes equal to or lower than the atmospheric pressure, the spray nozzle 4 On the side, the pressure in the oil return pipe 5a can always be kept higher than the atmospheric pressure (the spring load of the compression coil spring 55 is set as such).

As a result, even if the installation position of the oil tank 1 is lower than that of the fuel supply device, the phenomenon that air is sucked from the tip of the spray nozzle 4 into the oil return pipe 5 does not occur when the combustion amount is reduced. .

According to the present invention, the throttle portion of the oil feed pipe 2 is a fixed throttle, and the force applied to the surface of the diaphragm 30 is varied by a solenoid magnet device or the like, so that the oil feed pipe 2 upstream and downstream of the fixed throttle can be changed. You may apply to what was comprised so that the differential pressure inside could be controlled.

In this case, by controlling the differential pressure across the fixed throttle of the oil feed pipe by means of a solenoid magnet device or the like, the flow rate of petroleum used for combustion can be directly and accurately controlled, and following it. The flow rate of oil returned through the oil return pipe 5 changes. The constant differential pressure valve 50 operates in exactly the same manner as the above-mentioned embodiment.

Further, the constant differential pressure valve of the present invention is not limited to the one having the structure shown in the embodiment, and various embodiments can be adopted. Further, the oil tank may be installed at a position higher than the fuel supply device.

[0039]

According to the present invention, the flow rate of the fuel used for combustion in the spray nozzle can be directly and accurately controlled from the flow passage area of the throttle portion and the differential pressure across the same time. Since it is possible to maintain the pressure in the return pipe at the spray nozzle side so that it does not fall below atmospheric pressure, even if the installation position of the fuel tank is low, air is not drawn into the return pipe from the tip of the spray nozzle, A stable combustion state can be obtained.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an embodiment.

FIG. 2 is a configuration diagram of a spray nozzle according to an embodiment.

[Explanation of symbols]

 1 Oil Tank 2 Oil Feed Pipe 3 Fuel Pump 4 Spray Nozzle 5 Oil Return Pipe 9 Confluence Section 12 Return Pipe Line Valve 17 Feed Pipe Line Valve 19 Valve Seat 30 Diaphragm (Differential Pressure Operating Means) 50 Constant Differential Pressure Valve

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. 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 flow passage area of the feed pipe upstream of the joining portion. In the return pipe of the return pipe valve part, a throttle part for throttling, a differential pressure operating means for operating the return pipe valve by operating by a pressure difference in the feed pipe upstream and downstream of the throttle part. And a constant differential pressure valve for maintaining the pressure in the return pipe of the spray nozzle portion higher than the pressure of the above.