JPS6349132B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a combustion control method for a burner that performs two-stage combustion by switching the amount of fuel and combustion air into two stages.

Generally, in this type of burner, when the burner output is switched between high and low levels during combustion, the balance between the fuel and the combustion air is disrupted, especially immediately after switching, and as a result,
The drawback is that unstable combustion occurs temporarily. This is because the combustion air is forcedly blown by a fan, and the rotation of the fan motor that drives the fan is not synchronized with the increase/decrease operation of the fuel supply amount. In other words, the amount of fuel supplied can be increased or decreased instantaneously by mechanical means, but since the fan is rotated by the fan motor, when switching the burner output from strong combustion to weak combustion, the fan motor must be rotated at high speed. Due to inertia, it is extremely difficult to immediately shift from low-speed rotation to low-speed rotation, and even if the fuel supply decreases, the air volume does not immediately decrease, and when switching from weak combustion to strong combustion, the fan motor is There is a time delay when the amount of fuel supplied increases and the air volume is blown at an amount commensurate with strong combustion before the high-speed rotation of the burner is performed. Synchronization of switching operations between the amount of fuel supplied and the amount of combustion air blown during switching has become an extremely important issue in burner combustion control.

Therefore, the present invention provides a burner combustion control method that synchronizes the switching operation of the fuel supply amount and the combustion air blowing amount at the time of switching the burner output to two stages of high and low power for combustion. The purpose is to

Next, the present invention will be explained in detail with reference to the embodiments shown in FIGS. 1, 2, 3, and 4. In the figure, 1 is an electromagnetic pump that supplies fuel to burner B, and 1 is on the suction side.
It is connected to the fuel tank at point a, and connected in series to a pump switch 2 via a diode D, and when switch 2 is turned on, it receives electricity from a commercial power source V and is driven. A feedback valve 31 is connected between the electromagnetic pump and the orifice 11 through the electromagnetic valve 3. When the electromagnetic valve opens, the fuel is returned to the pump suction side, and when the pressure decreases and the orifice is closed, the entire amount flows to the orifice. Maintain pressure (Figure 1). Solenoid valve 3 and feedback valve 31
As described above, the fuel pump 1 has the function of controlling the pressure of the fuel delivered by driving the electromagnetic pump 1. Reference numeral 4 denotes a fan motor that drives a fan for blowing air for combustion of primary air and secondary air.This fan motor 4 and the solenoid valve 3 operate in the relationship described below, and This setting is made to prevent excessive air from being pumped in when switching to weak combustion.

5 is a switch that changes the strength of combustion.
This switch 5 is set so that when it is open, strong combustion occurs, and when it is closed, it causes weak combustion. This switch 5 has three pairs of contacts R-1a, R-1b,
A relay R-1 having R-1a', R-1b' and R-1a'', R-1b'' is connected. That is, when the changeover switch 5 is closed during weak combustion, the relay R-1 is energized and the contacts R-1a, R-1a', R
-1a'' is closed. Also, in the case of strong combustion, by opening the changeover switch 5, the excitation of relay R-1 is released, and contacts R-1b, R-1b', R-1b'' are closed. Close.

Relay R-2 is a relay that is energized by closing contact T-2b' of a delay timer, which will be explained after switching switch 5 is closed.
-1 is connected in parallel. And contact point R-
2a and R-2b, the contact R-2a is located to open and close the energization to the terminal B for reverse rotation of the fan motor 4, and the contact R-2b is the terminal for forward rotation of the fan motor 4. It is placed at a position that reduces the amount of current flowing between A and C.

When the contact R-2a is closed, the fan motor 4
Terminal B for reverse rotation is connected to relay R via resistor 6.
A circuit is formed which leads to the contact R-1a of the fan motor 4 through the resistor 6 when the contact R-2b is closed. is formed. The reason for this configuration is that the contact R-2a initially closes and energizes the fan motor 4 in the reverse rotation direction to apply sudden braking, and then the contact R-2a
This is to shift to low speed rotation by opening contact R-2a and closing contact R-2b to drop the voltage via resistor 6. This causes the fan motor to rotate when the selector switch 5 is turned on. 4 instantaneously shifts to low-speed rotation to cut off excessive air supply, making it possible to supply air commensurate with the amount of fuel supplied for weak combustion.

T-1 is a delay timer configured to operate by closing contact R-1b', which causes contact T-1b to open after a set time.
is located between the contact R-1b' and the contact R-1b''.

T-2 is also a delay timer and is configured to operate by closing contact R-1a', and this operation causes contact T-2a to be closed after a set time.
is located between contacts R-1a' and R-1a'' and is likewise opened after a set time. Contact T-2b' is located in series with relay R-2.

Next, the operation will be explained. pump switch 2
During strong combustion when the electromagnetic pump 1 is turned on and the electromagnetic pump 1 is operated, the changeover switch 5 is open and the relay R-1 is in an inoperative state. Therefore, relay R
-1 contacts R-1b, R-1b', R-1b'' are closed.The fan motor 4
Electricity is supplied through -1b and it rotates at high speed. Further, the delay relay T-1 is energized through the contact R-1b' and is in an operating state, and the contact T-1b is open. Therefore, the solenoid valve 3 does not operate, and fuel supply commensurate with strong combustion continues. At this time, relay R-2 is energized through contact T-2b' of delay timer T-2 and is in operation, with contact R-2a closed and R-2b open.

Next, a case will be described in which the changeover switch 5 is turned on to switch to a weak combustion state. As a result of this operation, relay R-1 operates, contact R-1
a, R-1a', R-1a'' are closed. Therefore,
The fan motor 4 is energized through the contact R-2a, receives a rotational force in the opposite direction, and is suddenly braked.
On the other hand, the delay timer T-2 is set to operate with a delay of the minimum time _t2 necessary for the motor to reach rotation suitable for weak combustion due to reverse rotation braking, and is energized through contact R-1a'. After a delay of ₂ hours, contact T-2a is closed, and contact T-2a is closed.
-2b' is open. During the delay time _t2 when both contacts reach the above operation, the contact R-2a is in the closed state, so that the motor receives sufficient braking.
Eventually, after _t2 , delay relay T-2 operates and its contacts switch as described above, so relay R-2 is de-energized, contact R-2a is opened, and contact R-2 is closed.
b is closed, and the fan motor 4 is energized for low speed rotation. At the same time, the contact T-2a is closed, which causes the solenoid valve 3 to operate, thereby controlling the amount of fuel supplied to an amount suitable for weak combustion.

Furthermore, when switching from a weak combustion state to a strong combustion state, relay R-1 stops operating, so power is supplied through contact R-1b, and fan motor 4 rotates at high speed with a short startup time _t1. Move to
Increase air flow. On the other hand, the delay timer T-1 is set to operate with a delay of a time equal to the motor's rise time _t1 , and even if electricity is applied through contact R-1b', there is a delay of _t1 , so this time After , the contact T-1b is opened and the operation of the solenoid valve 3 is stopped. During this time, the fan motor 4 completely returns to high speed rotation, and there is no imbalance between the amount of fuel supplied and the amount of air blown. Incidentally, since the motor start-up time _t1 is a short time, the fuel switching delay operation by the delay timer T-1 may be omitted.

Therefore, even when the air blowing amount is changed from the strong combustion state to the weak combustion state or vice versa, it is possible to achieve complete synchronization with the fuel supply amount, and it is possible to avoid a combustion failure due to an excess or deficiency of the air blowing amount.

FIG. 5 shows another embodiment of the present invention, which is different from the previous example in that when braking the fan motor 4, the input voltage is applied directly without going through the resistor 6. different. This has the effect of increasing the braking effect, and also increases the delay relay T.
-2 delay time t ₂ can also be shortened.

As described above, when switching the output of the burner from strong combustion to weak combustion, it was difficult in the past to quickly shift from strong rotation to weak rotation due to the characteristics of the fan motor. Since the fan motor is sometimes braked by applying a rotational force in the opposite direction, it has the effect of instantaneously shifting to weak combustion.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a mechanism for increasing/decreasing the amount of fuel supplied in an embodiment of the present invention, FIG. 2 is a wiring diagram of a capacitor motor, FIG. 3 is an operational diagram showing a combustion sequence, and FIG. Similarly, FIG. 5 is a circuit diagram of the combustion control mechanism, and is a circuit diagram of another example of the combustion control mechanism. 1... Solenoid pump, 3... Solenoid valve, 31... Feedback valve, 4... Fan motor, 5... Selector switch.

Claims (1)

[Claims] 1 In a combustion control method in which the amount of fuel and combustion air is switched between strong and weak two-stage combustion, when switching from strong combustion to weak combustion, immediately before switching the fan motor from strong rotation to weak rotation, the fan motor is stopped by reverse phase braking. The feature is that by temporarily applying a starting force for reverse rotation to the motor and rapidly shifting the rotation of the fan motor to a low rotation, the amount of combustion air is instantly controlled to match weak combustion. Combustion control method.