JP2002071126A - Reverse flow preventing apparatus of water mixing burner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the reverse flow of fuel oil from the mixing part of the fuel oil and water to a water feeding line in a water mixing burner. SOLUTION: A water mixing burner is arranged with a fuel feeding pump 3 and a fuel shutting valve 4 at the middle of a fuel feeding line 1, and a water feeding pump 5 and a water shutting valve 6 at the middle of a water feeding line 2. The water mixing burner is provided with a discharge pressure detector 9 detecting the pressure at the downstream of the water feeding pump, and presetting a normal pressure at the mixing part of the fuel oil and the water during the burning of the burner. The operation of the fuel feeding pump 3 and the opening of the fuel shutting valve 4 are controlled at the start of the burning of the burner. The water feeding pump 5 is operated while the water shutting valve 5 is closed, to compare mixing part pressure detected by a mixing part pressure detector 8 with the preset normal pressure. The water shutting valve 6 is controlled to open after confirming that the discharge pressure is higher than the normal pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backflow prevention device in a water mixing burner.

[0002]

2. Description of the Related Art The amount of NOx generated can be suppressed by burning a water mixture fuel obtained by mixing fuel oil and water. As a method of burning a water-mixed fuel, a method of mixing fuel oil, water, and an emulsifier and burning the mixture as an emulsion fuel,
There is a method in which fuel oil and water are mixed immediately before combustion, and combustion is performed while water is dispersed in the fuel. In the case of using an emulsion fuel, since the fuel oil and water are stored in the tank, the fuel oil does not flow backward in the water supply line. However, when fuel oil and water are mixed immediately before combustion, the fuel oil and water are mixed and injected to perform combustion.
The pressure in the mixing section must be high, and the fuel supply line and the water supply line are directly connected so that the pressure can be transmitted to the mixing section. Therefore, when the water supply pressure is low due to a failure or a decrease in capacity of the water supply pump, the fuel oil may flow backward in the water supply line and the fuel oil may flow out.

[0003]

An object of the present invention is to prevent a fuel oil from flowing back from a fuel oil / water mixing section to a water supply line in a water mixing burner.

[0004]

A water-mixed fuel burner for mixing fuel oil supplied through a fuel supply line and water supplied through a water supply line to burn a fuel mixture of fuel oil and water, comprising: A fuel supply pump for applying pressure to fuel oil and a fuel cutoff valve for controlling fuel supply are provided in the middle of the supply line, and a water supply pump for applying pressure to water and a water supply pump are provided in the middle of the water supply line. A water shutoff valve for controlling the fuel supply pump, a fuel cutoff valve, a water supply pump, and a water mixing burner provided with a controller connected to each of the water cutoff valves by a signal line. A discharge pressure detecting device for detecting a pressure downstream of the water supply pump is provided, and the controller sets a standard pressure at a mixing point of fuel oil and water during burner combustion. Can, if you want to start the combustion of the burner,
The controller first controls the operation of the fuel supply pump and opens the fuel cutoff valve.The water supply pump is operated with the water cutoff valve closed, and the set standard pressure and discharge pressure are set in this state. The discharge pressure detected by the detection device is compared, and after confirming that the discharge pressure is higher than the standard pressure, control for opening the water cutoff valve is performed.

[0005] By operating the fuel supply pump and the water supply pump and opening the fuel cutoff valve and the water cutoff valve, a comparison between the standard pressure and the discharge pressure even when the fuel mixture of fuel oil and water is burning. When the discharge pressure is lower than the standard pressure, control is performed to close the water cutoff valve.

The water shutoff valve provided in the water supply line is an electrically operated valve which is less likely to leak, and a water solenoid valve for instantaneously controlling water supply is provided in the water supply line separately from the water shutoff valve. The valve is also connected to the controller, and when the discharge pressure is lower than the standard pressure, the control for closing the water solenoid valve is performed.

[0007] Instead of setting the standard pressure at the mixing point of fuel oil and water during burner combustion, a mixing section pressure detecting device for detecting the pressure at the mixing point of fuel oil and water is provided. The water shutoff valve is controlled by comparing the mixing unit pressure detected by the detection device with the discharge pressure detected by the discharge pressure detection device.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a flow chart of a liquid fuel burner at the nozzle tip water embodying the present invention, and FIG. 2 is a flowchart at the start of combustion in the liquid fuel burner at the nozzle tip water mixture.

The nozzle 10 mixes fuel oil and water at its tip and injects a water-mixed fuel. The nozzle 10 is connected to a fuel supply line 1 and a water supply line 2. The fuel supply line 1 is provided with a fuel supply pump 3 for applying pressure to fuel oil and sending the fuel oil to a nozzle 10, and an electromagnetic fuel cutoff valve 4 for instantaneously controlling the flow of fuel oil.
A mixing unit pressure detecting device 8 for detecting the pressure in the mixing unit is provided at the mixing location of the fuel oil and water. Water supply line 2
A water supply pump 5 for applying pressure to water and sending it to a nozzle 10, a discharge pressure detecting device 9 for detecting a discharge pressure of the water supply pump 5, and an electrically operated type capable of surely stopping the flow of water. A water shutoff valve 6 and an electromagnetic water solenoid valve 11 for instantaneously controlling the flow of water are provided. Controller 7 connected to each of fuel supply pump 3, fuel cutoff valve 4, water supply pump 5, water cutoff valve 6, water solenoid valve 11, mixing unit pressure detection device 8, and discharge pressure detection device 9 by signal lines. Is set up,
Each device is controlled by the controller 7.

Next, the sequence for starting the burner combustion will be described. When a command to start combustion is input to the controller 7,
The controller 7 issues an operation start command to the fuel supply pump 3 and performs control to open the fuel cutoff valve 4 in accordance with the operation of an ignition device (not shown). At the start of combustion, in order to improve the ignitability, combustion is started only with fuel oil without supplying water.

Although water is not mixed in the nozzle 10, the pressure is detected by the mixing unit pressure detecting device 8, and the mixing unit pressure P is output to the controller 7. Before supplying water, the controller 7 checks whether the water supply pump 5 is operating normally. The water supply pump 5 is operated while the water cutoff valve 6 and the water solenoid valve 11 are closed, and the discharge pressure detecting device 9 detects the discharge pressure P2.
The controller 7 compares the mixing unit pressure P detected by the mixing unit pressure detection device 8 with the discharge pressure P2 detected by the discharge pressure detection device 9, and compares the mixing unit pressure P with the discharge pressure P2. Is higher, the water supply OK is determined.

The controller 7 opens the water shutoff valve 6 and the water solenoid valve 11 and supplies water to the nozzle 10 if a predetermined time has elapsed from the start of combustion and the water supply is OK at that time. At the tip of the nozzle, the fuel oil and water are stirred and mixed, and the mixture is injected with water dispersed in the fuel oil to burn the water-mixed fuel. Discharge pressure P2 when a predetermined time has elapsed from the start of combustion
Is not higher than the mixing section pressure P,
Combustion is performed only with fuel oil without supplying water. In this case, the water supply pump 5 stops, and an abnormality is notified. When the water shutoff valve 6 and the water solenoid valve 11 are opened in a state where the discharge pressure P2 is lower than the mixing section pressure P, fuel oil enters the low pressure water supply line 2 from the high pressure nozzle 10 and the water supply line 2 The fuel oil will flow back. Therefore, in this case, the backflow of fuel oil to the water supply line 2 is prevented by not opening the water cutoff valve 6 and the water solenoid valve 11.

When the sequence at the start of combustion is completed, the combustion continues until a command to stop combustion or the like is input to the controller 7. While burning while mixing water,
The controller 7 compares the mixing unit pressure P detected by the mixing unit pressure detection device 8 with the discharge pressure P2 detected by the discharge pressure detection device 9. If the discharge pressure P2 is higher than the mixing section pressure P, the supply of water is continued. However, when the discharge pressure P2 becomes lower than the mixing section pressure P, the controller 7 performs control to close the water cutoff valve 6 and the water solenoid valve 11, and the water supply pump 5 stops to notify the abnormality. If the water shutoff valve 6 and the water solenoid valve 11 are opened in a state where the discharge pressure P2 is lower than the mixing section pressure P, fuel oil enters the low pressure water supply line 2 from the nozzle 10, and the water supply line 2 The fuel oil will flow back. Therefore, in this case, by closing the water cutoff valve 6 and the water solenoid valve 11, the backflow of the fuel oil to the water supply line 2 is prevented.

When a fuel stop command is input to the controller 7 or a signal indicating that the flame has been lost during combustion is input, the controller 7 closes the fuel cutoff valve 4, the water cutoff valve 6, and the water solenoid valve 11. , Fuel supply pump 3, water supply pump 5
To stop combustion. The reason why the water shutoff valve 6 and the water solenoid valve 11 are provided in the water supply line 2 is to prevent the backflow of the fuel oil and to instantaneously control the water supply to the nozzle 10. The solenoid valve can control the flow instantaneously, but there is a possibility that leakage may occur due to the bite getting caught in the valve body, etc. There is such a problem.

When the flame is out, the fuel supply line 1
When water is supplied to 0, water accumulates in the combustion furnace, causing non-ignition or poor combustion in the subsequent combustion. In this case, it is necessary to stop the water supply immediately.
When only the electric valve is used, water continues to flow until the valve is closed. However, if the water solenoid valve 11 is provided, the water supply can be stopped immediately, so that the above problem does not occur.
In addition, although there is a possibility that leakage may occur due to dust biting only with the solenoid valve, by providing the water shutoff valve 6 of the electric valve,
Even if the water solenoid valve 11 has a leak, the backflow of the fuel oil to the water supply line 2 can be prevented.

In this embodiment, the case where the mixing section pressure detecting device 8 is provided has been described. However, since the mixing section pressure during combustion is substantially constant, the value of the mixing section pressure is set as a standard pressure. Control may be performed using the standard pressure as the mixing section pressure P. When the standard pressure is set, the mixing unit pressure detecting device 8 is provided when the burner specification is examined, the standard pressure is read, and the value may be used as the standard pressure.
When manufacturing products of the same standard, it is not necessary to provide the mixing section pressure detecting device 8 for each product.

[0017]

By implementing the present invention, it is possible to prevent fuel oil from flowing back into the water supply line, and to prevent fuel oil from leaking to the water side.

[Brief description of the drawings]

FIG. 1 is a flow diagram of a liquid fuel burner at a nozzle tip water embodying the present invention.

FIG. 2 is a flowchart at the start of combustion in a liquid fuel burner at the nozzle tip water mixture type.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fuel supply line 2 Water supply line 3 Fuel supply pump 4 Fuel cutoff valve 5 Water supply pump 6 Water cutoff valve 7 Controller 8 Mixing part pressure detector 9 Discharge pressure detector 10 Nozzle 11 Water solenoid valve

Claims (4)

[Claims] 1. A water mixing burner for mixing fuel oil supplied through a fuel supply line and water supplied through a water supply line to burn a fuel mixture of fuel oil and water. A fuel supply pump for applying pressure to fuel oil and a fuel cutoff valve for controlling fuel supply are provided.A water supply pump for applying pressure to water and a water cutoff for controlling water supply are provided in the middle of the water supply line. A water mixing burner provided with a valve and having a controller connected to each of a fuel supply pump, a fuel cutoff valve, a water supply pump, and a water cutoff valve by a signal line. Provide a discharge pressure detection device that detects the pressure downstream than, the controller sets the standard pressure at the fuel oil and water mixing point during burner combustion,
When starting the burner combustion, the controller first controls the operation of the fuel supply pump and opens the fuel cutoff valve.The water supply pump is operated with the water cutoff valve closed, and in this state, the setting is performed. Comparing the standard pressure and the discharge pressure detected by the discharge pressure detection device, and confirming that the discharge pressure is higher than the standard pressure, and then performing control to open the water cutoff valve. Backflow prevention device in mixing burner. 2. The fuel-water-mixed burner according to claim 1, wherein the fuel supply pump and the water supply pump are operated to open the fuel cut-off valve and the water cut-off valve. When combustion is performed, the standard pressure and the discharge pressure are compared, and when the discharge pressure is lower than the standard pressure, the water shutoff valve is closed. Backflow prevention device in water mixing burner. 3. The backflow prevention device for a water mixing burner according to claim 1, wherein the water cutoff valve provided in the water supply line is an electric valve that is unlikely to leak, and the water supply line is provided with a water cutoff valve. Separately, a water solenoid valve that instantaneously controls water supply is provided, and the water solenoid valve is also connected to the controller.If the discharge pressure is lower than the standard pressure, the water solenoid valve is A backflow prevention device in a water mixing burner, wherein the backflow prevention device also performs control to close the water. 4. The backflow prevention device for a water mixing burner according to any one of claims 1 to 3, wherein instead of setting a standard pressure at a mixing point of fuel oil and water during combustion of the burner, fuel oil and water are mixed. A mixing unit pressure detector that detects the pressure at the water mixing point is provided, and the mixing unit pressure detected by the mixing unit pressure detector is compared with the discharge pressure detected by the discharge pressure detector to shut off the water. A backflow prevention device in a water mixing burner, which controls a valve.