JP4280402B2 - Backflow prevention device in water mixing burner - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a backflow prevention device in a water mixing burner.
[0002]
[Prior art]
By burning a water-mixed fuel obtained by mixing fuel oil and water, the amount of NOx generated can be suppressed. Combustion method of water-mixed fuel includes mixing fuel oil / water / emulsifier and burning as emulsion fuel, and mixing fuel oil and water just before combustion, while water is dispersed in fuel There are ways to burn. When the emulsion fuel is used, the fuel oil and water are accumulated in the tank, so that 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 injected while being mixed and burned, so the pressure in the mixing section needs to be high, and the fuel supply line and The water supply line is connected directly so that pressure can be transmitted to the mixing section. Therefore, when the water supply pressure is reduced due to a failure of the water supply pump or a reduction in capacity, the fuel oil may flow backward in the water supply line and the fuel oil may flow out.
[0003]
[Problems to be solved by the invention]
The problem to be solved by the present invention is to prevent the fuel oil from flowing backward from the fuel oil and water mixing section to the water supply line in the water mixing burner.
[0004]
[Means for Solving the Problems]
A water-mixed fuel combustion burner that mixes fuel oil supplied through a fuel supply line and water supplied through a water supply line and burns the fuel oil and water mixed fuel. A fuel supply pump that applies pressure to the fuel and a fuel shut-off valve that controls the fuel supply are provided. A water supply pump that applies pressure to the water and a water shut-off valve that controls the water supply are provided in the middle of the water supply line. In addition, in the water mixing burner provided with a controller connected to each of the fuel supply pump, the fuel cutoff valve, the water cutoff pump, and the water cutoff valve by a signal line, it is in the middle of the water supply line and downstream of the water supply pump A discharge pressure detection device that detects the pressure at the burner is provided. The controller sets the standard pressure at the fuel oil and water mixing point during burner combustion, and starts burner combustion. In this case, the controller first controls the fuel supply pump and opens the fuel shut-off valve, and keeps the water shut-off valve closed and operates the water supply pump. In this state, set the standard pressure and discharge Then, the discharge pressure detected by the pressure detection device is compared, and after confirming that the discharge pressure is higher than the standard pressure, control is performed to open the water shutoff valve.
[0005]
By operating the fuel supply pump and water supply pump and opening the fuel shutoff valve and water shutoff valve, even when the fuel mixture of fuel oil and water is burning, the standard pressure is compared with the discharge pressure, When the discharge pressure is lower than the standard pressure, control is performed to close the water shut-off valve.
[0006]
The water shut-off valve provided in the water supply line is an electric valve that does not easily leak, and the water supply line is provided with a water solenoid valve that instantaneously controls the water supply separately from the water shut-off valve. When the discharge pressure is lower than the standard pressure, the water solenoid valve is also controlled to close.
[0007]
Instead of setting the standard pressure at the fuel oil and water mixing location during burner combustion, a mixing section pressure detection device that detects the pressure at the fuel oil and water mixing location is provided. The water shutoff valve is controlled by comparing the mixing section pressure to be detected with the discharge pressure detected by the discharge pressure detecting device.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a flow chart of a nozzle tip water mixing type liquid fuel burner embodying the present invention, and FIG. 2 is a flowchart at the start of combustion in the nozzle tip water mixing type liquid fuel burner.
[0009]
The nozzle 10 mixes fuel oil and water at the tip and injects water-mixed fuel. The fuel supply line 1 and the water supply line 2 are connected to the nozzle 10. The fuel supply line 1 is provided with a fuel supply pump 3 that applies pressure to the fuel oil and sends it to the nozzle 10, and an electromagnetic fuel shut-off valve 4 that instantaneously controls the flow of the fuel oil. A mixing unit pressure detection device 8 for detecting the pressure in the mixing unit is provided at the water mixing location. In the water supply line 2, a water supply pump 5 that applies pressure to water and sends it to the nozzle 10, a discharge pressure detection device 9 that detects the discharge pressure of the water supply pump 5, and reliably stops the flow of water An electric water cutoff valve 6 that can be used and an electromagnetic water electromagnetic valve 11 that instantaneously controls the flow of water are provided. A controller 7 connected to each of the fuel supply pump 3, the fuel cutoff valve 4, the water supply pump 5, the water cutoff valve 6, the water electromagnetic valve 11, the mixing section pressure detection device 8, and the discharge pressure detection device 9 through signal lines. Each device is controlled by the controller 7.
[0010]
Next, the order in the case where combustion of the burner is started will be described. When a command to start combustion is input to the controller 7, the controller 7 instructs the fuel supply pump 3 to start operation, and performs control to open the fuel cutoff valve 4 in accordance with the operation of an ignition device (not shown). . In order to improve ignitability at the start of combustion, water is not supplied but combustion is started only with fuel oil.
[0011]
Although the water is not mixed at the nozzle 10, the mixing unit pressure detection device 8 detects the pressure and outputs the mixing unit pressure P to the controller 7. The controller 7 checks whether the water supply pump 5 is operating normally before supplying water. The water supply pump 5 is operated while the water shutoff valve 6 and the water electromagnetic valve 11 are closed, and the discharge pressure detecting device 9 discharges and detects the 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 the discharge pressure P2 is higher than the mixing unit pressure P. If it is higher, the water supply OK is judged.
[0012]
The controller 7 opens the water cutoff valve 6 and the water electromagnetic 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. Fuel oil and water are agitated and mixed at the tip of the nozzle, and the water-mixed fuel is burned by injection while water is dispersed in the fuel oil. When the discharge pressure P2 is not higher than the mixing section pressure P when a predetermined time has elapsed from the start of combustion, water is not supplied but combustion is performed only with fuel oil. In this case, the water supply pump 5 is stopped and an abnormality is notified. When the water shutoff valve 6 and the water electromagnetic valve 11 are opened in a state where the discharge pressure P2 is lower than the mixing part pressure P, the fuel oil enters from the high pressure nozzle 10 to the low pressure water supply line 2, and the water supply line 2 The fuel oil will flow backward. Therefore, in this case, the water shutoff valve 6 and the water electromagnetic valve 11 are not opened to prevent the backflow of fuel oil to the water supply line 2.
[0013]
When the sequence at the start of combustion is completed, the combustion is continued until a command for stopping combustion or the like is input to the controller 7. During the combustion while mixing water, the controller 7 uses the mixing unit pressure P detected by the mixing unit pressure detection device 8 and the discharge pressure P2 detected by the discharge pressure detection device 9. Compare. When the discharge pressure P2 is higher than the mixing section pressure P, the water supply 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 shutoff valve 6 and the water electromagnetic valve 11, and the water supply pump 5 stops and reports abnormality. If the water shutoff valve 6 and the water electromagnetic valve 11 are opened while the discharge pressure P2 is lower than the mixing section pressure P, the fuel oil enters the water supply line 2 having a low pressure from the nozzle 10 and the water supply line 2 Fuel oil will flow backward. Therefore, in this case, the water shutoff valve 6 and the water electromagnetic valve 11 are closed to prevent the reverse flow of the fuel oil to the water supply line 2.
[0014]
When a fuel stop command is input to the controller 7 or a signal that the flame has disappeared during combustion is input, the controller 7 closes the fuel cutoff valve 4, the water cutoff valve 6, and the water electromagnetic valve 11 to supply fuel. The pump 3 and the water supply pump 5 are stopped to stop the combustion. The reason why the water shutoff valve 6 and the water electromagnetic valve 11 are provided in the water supply line 2 is to prevent the backflow of 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 will occur due to dust biting in the valve body, etc. There is a problem that it takes.
[0015]
If water is supplied to the fuel supply line 10 when the flame is extinguished, water accumulates in the combustion furnace, causing non-ignition and poor combustion during the subsequent combustion. I need to stop. In the case of only the motorized valve, water continues to flow until the valve is closed. However, if the water electromagnetic valve 11 is provided, the water supply can be stopped immediately, so the above problem does not occur. In addition, there is a risk of leakage due to dust biting with the solenoid valve alone, but by providing the water shut-off valve 6 of the electric valve, even if leakage occurs in the water solenoid valve 11, the water supply of fuel oil Backflow to line 2 can be prevented.
[0016]
In this embodiment, the case where the mixing unit pressure detecting device 8 is provided has been described. However, since the mixing unit pressure during combustion is substantially constant, the value of the mixing unit pressure is set as the standard pressure, and the standard pressure is set to Control may be performed as the mixing section pressure P. When the standard pressure is set, the mixing section pressure detector 8 is provided when the burner specification is examined, the standard pressure is read, and the value can be used as the standard pressure. Therefore, it is not necessary to provide the mixing section pressure detection device 8 for each product.
[0017]
【The invention's effect】
By carrying out the present invention, it is possible to prevent the fuel oil from flowing back to the water supply line and to prevent the fuel oil from leaking to the water side.
[Brief description of the drawings]
FIG. 1 is a flow chart of a nozzle tip water-mixed liquid fuel burner embodying the present invention. FIG. 2 is a flowchart at the start of combustion in a nozzle tip water-mixed liquid fuel burner.
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 detection device 9 Discharge pressure detection device 10 Nozzle 11 Water solenoid valve

Claims (4)

A water mixing burner that mixes fuel oil supplied through the fuel supply line and water supplied through the water supply line and burns the fuel oil and water mixed fuel. In the middle of the fuel supply line, pressure is applied to the fuel oil. A fuel supply pump for adding water and a fuel cutoff valve for controlling fuel supply are provided, and a water supply pump for applying pressure to water and a water cutoff valve for controlling water supply are provided in the middle of the water supply line. In a water mixing burner provided with a controller connected to each of a fuel supply pump, a fuel cutoff valve, a water cutoff pump, and a water cutoff valve by a signal line, the pressure in the middle of the water supply line and downstream of the water supply pump When the burner combustion is started, the controller sets the standard pressure at the fuel oil and water mixing point during burner combustion. The trawler first controls the fuel supply pump and opens the fuel shut-off valve. The water shut-off valve is closed and the water supply pump is operated. In this state, the set standard pressure and discharge pressure are set. A backflow prevention device for a water mixing burner characterized in that the discharge pressure detected by the detection device is compared and control is performed to open the water shutoff valve after confirming that the discharge pressure is higher than the standard pressure. 2. The backflow prevention device for a water mixing burner according to claim 1, wherein the fuel supply pump and the water supply pump are operated to open the fuel cutoff valve and the water cutoff valve to burn the mixed fuel of fuel oil and water. In this case, the backflow in the water mixing burner is characterized in that a comparison is made between the standard pressure and the discharge pressure, and when the discharge pressure becomes lower than the standard pressure, the water shutoff valve is controlled to close. Prevention device. 3. The backflow prevention device for a water mixing burner according to claim 1 or 2, wherein the water shut-off valve provided in the water supply line is an electric valve that is unlikely to leak, and the water supply line has a water A water solenoid valve that controls the supply instantaneously 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 also closed. A backflow prevention device for a water mixing burner characterized by the above. In the backflow prevention apparatus in the water mixing burner according to any one of claims 1 to 3, in place of setting a standard pressure at a fuel oil and water mixing location during burner combustion, at a fuel oil and water mixing location. A mixing unit pressure detection device for detecting pressure is provided, and the water shutoff valve is controlled by comparing the mixing unit pressure detected by the mixing unit pressure detection device with the discharge pressure detected by the discharge pressure detection device. A backflow prevention device for a water mixing burner characterized by the above.

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