FI98955C - Crucible type oil burner - Google Patents

Description

98955

This invention relates to a crucible-type oil burner, and more particularly to a crucible-type oil burner capable of burning any two or more fuels of different viscosities of choice, such as a desired combination of kerosene, light fuel oil and waste oil, waste oil and waste oil. a combination of kerosene and waste oil and the like.

In general, a crucible-type oil burner usually comprises a crucible mounted in an air duct defined in the burner body, supplied with combustion air and suitable for performing fuel evaporation, mixing the evaporated fuel and air into a mixture, and burning the mixture; an electromagnetic pump suitable for supplying fuel from the fuel tank through the fuel supply pipe 20 to the crucible; The pump control device also comprises means for changing the frequency of the switch-on signal and the burning rate is controlled by varying the frequency of the switch-on signal by means of the burner controller and by controlling the amount of fuel fed to the crucible by means of an electromagnetic pump. The crucible-type oil burner thus designed enables the selective combustion of fuels of different viscosities. Furthermore, this burner allows the use of kerosene initially to cause ignition 35 and to stabilize combustion, as well as the subsequent replacement of kerosene with light fuel oil to continue combustion.

2 98955

Kerosene, light fuel oil and waste oil differ in their viscosity. Therefore, even when the oil regulator for adjusting the amount of oil fed to the crucible is set to a certain level, the burn rate varies depending on the type of oil used. Thus, when a person unfamiliar with the use of a burner using a crucible-type oil burner often results in incomplete combustion, which causes dangerous situations. Such a disadvantage tends to occur after the exchange of fuels of different viscosities has taken place or when two or more fuels of different viscosities are used in parallel. To avoid such a problem, the user is required to adjust the burn rate while checking the burn each time a change occurs. A conventional type of oil-15 burner is thus dangerous and very cumbersome to use.

A well-known crucible-type oil burner is often designed to allow automatic adjustment of the burn rate or fuel feed rate. To this end, the frequency of the switch-on signal of the pump control device 20 is automatically varied according to the control data set for the specific fuel used. Unfortunately, this requires the production of control data according to the viscosity of the spent fuel as well as the intended combinations of fuels, which makes the pump control device very complex.

The present invention has been made in view of the above-mentioned disadvantages of the prior art.

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It is therefore an object of the present invention to provide: a crucible-type oil burner capable of overcoming the disadvantages of the prior art described above while ensuring control of the combustion rate and thus the fuel supply rate 35 in substantially the same manner as the prior art.

Another object of the present invention is to provide a crucible-type burner capable of automatically controlling the burn rate or fuel feed rate with less than 3,99595 control data regardless of the type of fuel used and / or its viscosity.

It is a further object of the present invention to provide a crucible-type oil burner capable of fulfilling the above object while preventing the burner from becoming complex.

According to the present invention, there is provided a crucible type oil burner 10 generally comprising a burner body equipped with an air duct, a crucible mounted in the air duct to effect evaporation, mixing and burning fuel fed thereto, , the electromagnetic pump comprising an excitation coil, and the pump monitoring device comprising means for generating a power-up signal for the power-up signal at a desired frequency and a switching circuit connected to the excitation coil and adapted to reproduce the power-on input signal.

In a crucible-type oil burner constructed generally as described above, the switching signal generating means comprises a control member adjusted according to the viscosity of the fuel. The switching signal generating means is designed so that when the control member is adjusted according to the viscosity of the fuel used, the signal length of the switching signal varies expediently according to the viscosity.

‘Removal of fuel through the electromagnetic pump cylinder 35 is difficult when increasing the viscosity of the spent fuel. Therefore, when high viscosity fuel is used, the passage of the excitation current through the excitation coil during the same period as when low viscosity fuel is used is not sufficient to remove all the fuel from the cylinder of the electromagnetic pump. With respect to this problem, the control designed for the present invention by means of a control element, such as a switch or the like, allows the signal length of the switch-on signal to vary according to the type of fuel used and / or its viscosity. Such a design allows the same amount of fuel to be continuously fed to the crucible regardless of the fuel used, thus ensuring safe combustion with combustion control implemented in substantially the same manner as in the prior art. Similarly, a crucible-type oil burner is often constructed to allow automatic control of the amount of combustion or the rate of fuel supply. The present invention also relates to such a burner structure; since the present invention allows the same amount of fuel 15 to be fed to the crucible regardless of the fuel used, it thus allows the same control information to be used regardless of the fuel, allowing automatic adjustment. Thus, the present invention reduces the amount of control information required, thereby simplifying the pump control device.

The means for generating the switch-on signal of the pump control device can be implemented with either hardware or software. When the arming signal generating means is implemented in the apparatus, it may comprise an oscillator for producing an oscillation signal having a selected frequency and a circuit for generating an arming signal which is synchronized with the oscillation signal applied thereto. a signal for determining the signal length of the signal length switching circuit, and a control element is connected to the signal length determining circuit for adjusting the time constant of the signal length determining circuit. The frequency of the oscillator is adjusted with the burner controller. When it is adjusted automatically, the control information is placed in the burner controller, whereby the frequency is automatically adjusted according to the control information. For example, the control information is set so that the frequency increases when the amount of combustion is at a low level as in ignition and decreases when the amount is at a high level as in combustion. The control information may include information on the transfer conditions from the ignition phase to the combustion phase, information to maintain a constant temperature, and the like.

The power-on signal generating circuit may comprise a single-position multivibrator capable of adjusting the signal length of the power-on signal, wherein the control element comprises a manual switch mounted on the signal circuit determining the signal length of the single-position multivibrator for determining the signal length. The single-position multivibrator is suitable for use in a power-up signal generating circuit because it is inexpensive and quickly adjusts the sig-15 signal length of the power-on signal.

When the switching signal generating means is implemented by software, it may comprise a microcomputer operated according to a predetermined program, wherein the control element 20 includes a conditional switch for changing the original conditions of the program. The predetermined program may comprise a reference signal generating routine for implementing a reference signal generating means for generating a reference signal each time a predetermined count of 25 reference clock pulses is counted and a power-up signal generating routine the condition setting switch causes the predetermined reading of the power-on signal generation routine to change. Depending on the viscosity of the fuel used, the conditional switch acting as a control member changes the predetermined reading of the switch-on signal generation routine.

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Alternatively, the predetermined program may comprise a reference signal generating routine for implementing the reference signal generating means, the routine generating the reference signal when a predetermined number of reference clock pulses 6 98955 is computed after the reset signal is input to calculating a predetermined reading to supply the switching circuit with a continuous signal as a power-on signal, and then producing a reset signal when the predetermined reference clock pulse count is calculated, wherein the conditional switch causes the power-on signal generation routine to change the predetermined reading. Similarly, depending on the viscosity of the fuel used, the conditional switch acting as a control element changes the predetermined reading of the routine-producing switching signal. The program causes the frequency of the reference signal to vary somewhat, however, the program itself is simple. The slight variation in the frequency of the reference signal does not substantially impair the advantages of the present invention.

These and other objects of the present invention, as well as the resulting advantages, can be readily appreciated by better understanding of the following detailed description taken in conjunction with the accompanying drawings, in which: Figure 1 is a schematic vertical elevational view showing an embodiment of a crucible type oil burner according to the present invention; , Fig. 2 is a schematic graph showing a pump control device connected to the crucible-type oil burner shown in Fig. 1, and Fig. 3 is a circuit diagram showing an example of a circuit for the pump control device shown in Fig. 2.

A crucible-type oil burner according to the present invention will now be explained below with reference to the accompanying drawings.

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First, Fig. 1 shows a general structure of an embodiment of a crucible-type oil burner according to the present invention. The crucible-type oil burner of the illustrated embodiment can be constructed in substantially the same manner as the conventional crucible-type oil burner, except for the pump control device, which will be explained in detail below. The crucible-type oil burner of the illustrated embodiment comprises a cylindrical crucible 10, the side wall 12 of which is arranged to have a number of small through-openings 14. The cylindrical crucible 10 is mounted in an air duct 16 bounded by the burner body 18 so that the passage 16 surrounds the crucible 10 the bottom wall. The air duct 16 communicates with an air blower 12 suitable for strongly supplying combustion air through the air duct 16 to the crucible 10. The crucible type oil burner also comprises an oil tank 22 mounted on the burner body 18 and an electromagnetic pump 24 mounted on the oil tank 22 so as to communicate with each other. Between the electromagnetic pump 24 and the crucible 10, a fuel supply pipe 26 is arranged so that the electromagnetic pump 24 and the crucible 10 communicate with each other through it, the driving force of the electromagnetic pump 24 allowing a strong supply of fuel oil from the oil tank 22 through the fuel supply pipe 26 to the crucible.

In the illustrated embodiment, the fuel supply pipe 26 is mounted so as to protrude at one end into the oil tank 22 and at the other end into the crucible 10, the electromagnetic pump 24 being mounted in an intermediate portion of the fuel supply pipe 26.

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The crucible-type oil burner of the illustrated embodiment further comprises a preheating and igniting heater 28 mounted on the crucible 10 so as to be located near the bottom wall of the crucible 10. The crucible 10 is also provided with 35 combustion members 30 located above the heater 28. The combustion member 30 operates by completely mixing near the bottom of the crucible 10 the evaporating combustible gas with air supplied from the air duct 16 through small vias 14 to the crucible to form the combustion gas, thus enabling 8 98955 .

Figure 2 shows a schematic example of a control device for an electromagnetic pump 24 implemented by means of an apparatus. The pump control device comprises a burner controller 101 comprising a timer element, a plurality of sensors, a microcomputer for control and the like, and operations for generating a combustion rate signal to determine the combustion rate or fuel supply rate according to an operator-controlled operation. The burner controller 101 changes the burn rate signal according to the amount of use of the control knob in manual control, whereas when automatic control is used, the burner controller 101 automatically changes the burn rate signal according to the set control information. Reference numeral 102 denotes an oscillator whose oscillation frequency varies according to the burn rate signal. Oscillator 102 produces an oscillation signal, which is then applied to the input terminal of a single-position multivibrator 103, which is used as a power-producing signal generating circuit.

The single-position multivibrator 103 comprises a signal length determining circuit for determining the signal lengths, which is the signal produced by the single position multivibrator 103, and a switch 104 connected thereto for adjusting the time constant of the signal length determining circuit for the signal length of the switching signal. For example, when the switch 104 is switched between three different positions 30 as in Figure 2, the positions can be assigned to kerosene, light fuel oil and waste oil, respectively. Alternatively, the positions can be determined according to the viscosity grades of the fuel used, which are all different, for example according to the low, medium-35 and high viscosity coefficients, respectively. In all cases, the alignment of the switching stages of the switch 104 is performed so that the signal length of the switching signal can be increased as the viscosity of the spent fuel increases. The crucible-type oil burner can be adapted to use only one type of fuel for each combustion operation. In this case, due to the fuel change, the switch 104 is switched according to the viscosity 5 of the last fuel introduced into the oil tank 22. When the burner is adapted to interchangeably or optionally run one of two or more fuels simultaneously discharged into the burner, the changeover of the switch 104 is performed in connection with the change of fuels. When the fuel change is performed automatically, the switch 104 is automatically switched in connection with the automatic change.

The switch-on signal i produced by the single-position multivibrator 11a 103 is then fed to a capability circuit 105 which includes a control circuit comprising resistors R1 and R2 and a transistor TRI, which is a kind of semiconductor switching element. The emitter-collector circuit of the transistor TRI is connected in series with the excitation coil of the electromagnetic pump 24, whereby the excitation current passes through the excitation coil of the electromagnetic pump 24 for the period during which the transistor TRI is considered conductive. During this period, the piston 24 of the electromagnetic pump is forced into a position that allows fuel to escape. Connected in parallel with the excitation coil 24 of the electromagnetic pump is a diode DI comprising a flywheel diode.

In the illustrated embodiment, the oscillator 102 and the single-position multivibrator 103 cooperate with each other to form a power-generating signal generating member 30.

It is required that the switch 104 be set to a position where kerosene can be used as the fuel for the burner; when it is desired to use light fuel oil as fuel, the switch 35 104 is set to a position that allows the use of light fuel oil. This results in an increase in the signal length of the switch-on signal produced by the single-position multivibrator 103 corresponding to the increase in fuel viscosity due to the choice of light fuel oil, allowing the electromagnetic pump 24 to completely discharge the viscosity through the fuel or light fuel oil cylinder. Thus, even when the frequency of the oscillator 102 is set to the same as when kerosene is used as fuel, substantially the same amount of combustion as in kerosene is obtained. Similarly, when kerosene is used for ignition and light fuel oil is used only for combustion, an appropriate amount of combustion is obtained with the changeover circuit 10 of the switch 104 alone when changing fuels.

Fig. 3 shows an example of a circuit diagram for the pump control device shown in Fig. 2. The same reference numerals used in Figs. 2 and 3 denote the same parts and the parts shown in connection with Fig. 2 are substantially removed from the following description in connection with Fig. 3 to shorten the description. Thus, the burner controller 101 is removed from the circuit shown in Fig. 3, the switch 104 is adapted to perform switching in one single stage, and the switching circuit 105 comprises two transistors TR1 and TR2 connected together by a Dar1ington connection. Resistor R3 and zener diode ZDI cooperate with each other and form a constant voltage circuit.

The operation of the oscillator 102 will now be explained with reference to Fig. 3. When the voltage across the capacitor C1 connected to the negative input terminal of the comparator CP1 comprising the integrated circuit is small compared to the voltage applied to the positive input terminal of the comparator CP1, the output of the comparator CP1 is increased. causes the capacitor C1 to be charged through the diode D2 and the resistor R7. As the voltage across the capacitor C1 increases to a level above the voltage applied to the positive input 35 of the comparator CP1, the output of the comparator CP1 is made low so that the discharge of the capacitor C1 is effected through the resistors R8 and R9. Such an operation is then repeated so that the oscillation signal can be applied from the oscillator 102 to the input terminal of the single-position 11 98955 multivibrator 103. Both outputs of the burner controller 101 (adjustable impedance) are connected in parallel to both ends of the resistor R9, so that the variation of the output impedance of the burner controller 101 causes a variation of the impedance of the discharge circuit of the capacitor C1 and results in a variation of the oscillation frequency.

The operation of the single-position multivibrator 103 will now also be explained. When the output of oscillator 102 is kept low-10, capacitor C3 is charged through resistor R12 and adjustable resistor VR1. The voltage across the capacitor C3 is limited by the impact voltage through the zener diode ZD2. When the output of the oscillator 102 is high, the differential signal of the oscillation signal of the oscillator 102, which is differentiated by a derivative circuit comprising a resistor R10, a capacitor C2 and a resistor R11, is applied to the base of the transistor TR2, causing the transistor TR2 to be instantaneously conducting. The voltage across capacitor C3 is connected to the negative supply terminal of comparator CP2. The divider voltage of the divider circuit comprising resistors R14 and R15 is applied to the positive input terminal of the comparator CP2. The divider circuit comprises resistors R14, R15 and R16 with switch 104 closed. The output of comparator CP2 is kept high until transistor TR2 is made non-conductive to initiate charging of capacitor C3 so that the voltage across capacitor C3 reaches the level of the voltage connected to the positive supply terminal of comparator CP2. When the voltage across the capacitor C3 exceeds the voltage connected to the positive supply terminal of the comparator CP2, the output of the comparator CP2 is made low, after which it is kept low until the transistor TR2 is made conductive again. The variation of the voltage connected to the positive 'input terminal of the comparator CP2 allows the signal length of the power-on signal produced by the single-position multivibrator 103 to be varied. In the example shown in Figure 3, when the switch 104 is closed, the resistor R16 is connected in parallel to the resistor R15. This causes the voltage connected to the supply terminal of the comparator CP2 to decrease, thus reducing the signal length of the switching signal. In order to close the switch 104 to increase the signal length of the switch-on signal, it is only necessary to connect the resistor R16 and the serial circuit formed by the switch 104 in parallel with the resistor R14. Similarly, when the switch 104 is designed for three-stage switching, as in the embodiment shown in Fig. 2, two series circuits, each comprising a resistor and a switch, are connected in parallel with the resistor R14 or R15. In the illustrated embodiment, the resistors R14, R15 and R16 and the switch 104 cooperate and form a signal length determining circuit, and the resistor R16 and the switch 104 form a control element for adjusting the signal length of the power-on signal. The series-15 circuit formed by the resistor R16 and the switch 104 may be replaced by a circuit containing an element capable of varying the impedance, such as an adjustable resistor or the like.

In the illustrated embodiment, most of the control device of the pump 20 is hardware. Alternatively, the power-generating signal generating member formed by the oscillator 102 and the single-position multivibrator 103 may be implemented in software utilizing a microcomputer. The program used to implement the switching signal generating means 25 by means of the microcomputer may comprise, for example, a reference signal generating routine for implementing the reference signal generating means each time a predetermined number of reference clock pulses is counted and the switching signal 105 continues from generating a reference signal versus calculating a predetermined reading of the clock pulses as a power-up signal. According to the program thus prepared, it is possible to change the predetermined reading of the routine generating the power-on signal 35 using a conditional switch and thus adjust the length of the power-on signal. The program can be prepared in a simpler way. To this end, the reference signal generating means implemented by the reference signal generating routine is constructed to produce a reference signal when a predetermined number of reference clock pulses are counted when a reset signal is input thereto, and a power-up signal generating routine is established by field circuit 105 with a signal that continues until a predetermined number of reference clock pulses is counted after the reference signal is produced as a power-on signal, and thus produces a reset signal when a predetermined number of reference clock pulses is calculated. In this case, the signal length of the power-on signal can be adjusted by changing the predetermined reading with a conditional switch.

The program used to implement the power-up signal 15 generating means by means of the microcomputer is not limited to the above.

Although a preferred embodiment of the invention has been described in some detail with reference to the drawings, obvious modifications and variations can be made in light of the above principle. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.

Claims (7)

A crucible-type oil burner comprising a burner stand (18) provided with an air duct (16); a crucible (10) provided in the air duct for performing the displacement, mixing, and combustion of fuel fed therein; a fuel container (22); a fuel supply tube (26) arranged between the crucible and fuel container; An electromagnetic pump (24) for supplying fuel from the fuel container via the fuel feed tube to the crucible, the electromagnetic pump comprising a field coil; and a control device for the pump comprising a means (102, 17, 953) for generating a pointer switching signal of the selected frequency and a coupling circuit (105) coupled to the field coil and arranged to repeat a coupling operation dependent on the pointer coupling signal for supplying the field coil with a field Current, characterized in that the means generating the pointer switching signal comprises a control element (104) set according to the viscosity of the spent fuel and the means generating the pointer switch signal is designed so that the control element (104) is adjusted according to the using the viscosity of the fuel, the signal width of the pickup signal varies accordingly to the viscosity. A crucible-type oil burner according to claim 1, characterized in that the means generating the point-switch signal comprises an oscillator (102) for generating a vibration signal of the desired frequency and a circuit (103) which generates a point-switch signal and is measured with the vibration signal. The signal, and which generates the touch switch signal synchronously with the oscillation signal supplied thereto; wherein the circuit generating the touch switch signal comprises a circuit (R15, R16) which determines the signal width for determining the signal width of the touch switch signal; Wherein the control element (104) is incorporated into the circuit which determines the signal width in order to control a time constant of the circuit which determines the signal width. Crucible-type oil burner according to claim 2, characterized in that the circuit generating the touch-switch signal comprises a monostable multivibrator which increases the signal-width of the touch-switch signal; the control element comprises a manual coupling provided in the circuit which determines the signal width of the monostable multivibrator for controlling the impedance of the circuit which determines the signal width. 18 98955 4. A crucible-type oil burner according to claim 1, characterized in that the point generating signal generating means comprises a microcomputer operated according to a predetermined program and the control element comprises a conditional switch 5 for changing the output state of the program. A crucible-type oil burner according to claim 4, characterized in that the predetermined program comprises: a routine generating a reference signal for providing an organ generating the reference signal, for generating a reference signal each time a predetermined number of reference clock pulses are counted; and a routine generating pointer switching signal for generating a signal which continues from the generation of the reference signal to the count of the number of predetermined reference clock pulses, for supplying the switching circuit with the continuous signal as the pointer switching signal; wherein the conditional coupling causes the predetermined number of routine generating point coupling signal 20 to change. The crucible-type oil burner according to claim 4, characterized in that the predetermined program comprises: a routine generating a reference signal for providing an organ generating the reference signal generating a reference signal where a predetermined number of reference clock pulses is counted after a signal is counted thereto; a routine generating touch switch signal for generating a signal which continues from the generation of the reference signal to the count of the predetermined number of reference clock pulses, for supplying the switching circuit with the continuous signal as the touch switch signal, and generating thereafter the reset delay signal; wherein the conditional coupling causes the predetermined number of routines generating the tap coupling signal to change. 98955 19 7. A crucible-type oil burner according to claim 1, characterized in that the control device for the pump further comprises a control (101) with the intention of automatically changing the frequency of the tap connection signal for automatic installation of the combustion quantity.