JP3263785B2 - Method of manufacturing electromagnetic pump for fuel supply of oil combustor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel supply system for an oil combustor, which includes a step of selecting a fixed resistor for adjusting the discharge flow rate of an electromagnetic pump for sending oil to a burner, which is used for a small oil device such as a heater. The present invention relates to a method for manufacturing an electromagnetic pump.

[0002]

2. Description of the Related Art An electromagnetic pump reciprocates a plunger by applying a pulse current to an electromagnetic coil, thereby changing the volume between a suction valve and a discharge valve to suck a fluid and pressurizing the pump. The action was done. It is widely known that the discharge flow rate of the electromagnetic pump is proportional to the frequency of the pulse current, the duty ratio of the pulse, and the peak value (voltage) of the pulse.

[0003] The history of control of the discharge flow rate of an electromagnetic pump is based on the fact that, in the old days, a control circuit was assembled into an electromagnetic pump, adjusted to the required discharge amount, shipped, and further incorporated into an oil-fired machine, and then further controlled according to the combustion state. Had to readjust. Thereafter, since the control circuit is also incorporated in the combustor side, this control circuit is used, and the control circuit on the electromagnetic pump side is removed.

[0004] When used in a consumer oil burner, such as a fan heater, the discharge flow rate from an electromagnetic pump is:
The range of 1 to 10 cc / minute is controlled steplessly or several steps, and the tolerance is specified within ± 10%. However, in the case of the electromagnetic pump, the width of each individual pump natural maximum flow rate before adjustment has a variation of about 20 to 30%.

The change in magnetizing force, the change in magnetic force from the change in magnetic flux density, and the structure of the pump depend on the enamel wire diameter of the electromagnetic coil, the thickness of the insulating film, the fixed resistance, the number of turns, and the magnetic permeability of the magnetic circuit of the electromagnetic pump. When various factors such as dimensional accuracy of parts, surface roughness of finished surface, roundness, friction resistance during operation of electromagnetic plunger due to roundness, etc. are used, when adjusting the discharge flow rate with these electromagnetic pumps in the control circuit On the electromagnetic pump manufacturer's side, adjustment of the discharge flow rate is ± 2 to 4% of the predetermined discharge flow rate.
At present, it is regulated to a degree that is being delivered to combustor manufacturers.

As a means for adjusting the electromagnetic pump, a known fixed resistor is incorporated. That is,
The discharge flow rate is adjusted by controlling the peak value (voltage) of the pulse of the pulse current. As a well-known example for selecting a fixed resistor to incorporate a fixed resistor, Japanese Patent Publication No. 7-10103
No. 3 is known.

[0007] This known example includes an electromagnetic coil provided on the outer periphery of a cylinder containing a plunger in the form of a free piston, first and second terminals for fixing two coil terminals from the electromagnetic coil, and A third terminal to which a fixed resistor is connected between the first terminal and the first terminal; and a driving pulse supplied from a driving circuit in the oil combustor in a state where the driving resistor is incorporated in the oil combustor. 2. In a fuel supply electromagnetic pump of an oil combustor that is supplied between a third terminal and discharges fuel at a predetermined discharge amount, a drive circuit in the oil combustor without the fixed resistor. An electromagnetic pump is manufactured in advance so that the drive pulse supplied from the controller is equal to or greater than the predetermined discharge amount, and a drive pulse from the discharge amount inspection drive circuit is supplied to the first and second terminals. Measure the discharge amount of the electromagnetic pump, and According to the deviation between the discharge amount and the reference flow rate, a fixed resistor having a resistance value within an allowable range for the predetermined discharge amount in a state where the discharge amount of the electromagnetic pump is incorporated in the oil combustor is limited. And connecting the selected fixed resistor between the first and third terminals. "

In this known example, the relationship between the resistance of the same type of electromagnetic pump and the discharge flow rate is expressed by the following equation:
It is assumed that the relationship is almost linear and the inclination with respect to the horizontal axis is also almost constant.

However, in the case of the electromagnetic pump, not only the difference between the production rods, but also the same production rod, the individual pumps do not always have the linear characteristic diagram as described above. It is caused by various factors such as changes in the resistance value of the coil of the electromagnetic coil, variations in the magnetic material that forms the magnetic path such as the electromagnetic plunger, variations in the spring force of the upper and lower springs that support the electromagnetic plunger, and errors in assembling each part. The discharge flow rate of the pump is not generally linear and has a predetermined slope, but is curved and has individual variations.

Therefore, when the predetermined flow rate is adjusted and controlled by one flow rate measurement, that is, one point measurement, the probability of passing the predetermined flow rate tolerance is low because the characteristics of the electromagnetic pump are not uniform as described above. The problem was that it was uneconomical to start over again.

Accordingly, the present invention provides a method for manufacturing an electromagnetic pump including a step of selecting a new fixed resistor in order to improve the accuracy of the discharge flow rate of the electromagnetic pump and to provide a stable electromagnetic pump of high quality. .

[0012]

An electromagnetic pump according to the present invention comprises a plunger disposed in a cylinder and reciprocating;
An electromagnetic coil externally fitted to the outside of the cylinder, a check valve provided in a center hole of the plunger, a check valve provided in the cylinder, and a second valve connected to both ends of a winding of the electromagnetic coil. A first terminal, a third terminal for connecting a fixed resistor between the second terminal and the first terminal, and a desired driving pulse current is supplied from the driving circuit to the second terminal.
In the fuel supply electromagnetic pump for petroleum combustors, which is connected and applied between the third terminal and the third terminal to obtain a desired discharge flow rate, a drive pulse from a discharge flow rate detection drive circuit having the same or a predetermined relationship as the drive circuit When supplying a current between the first and second terminals, one of the first terminal and the second terminal has a design-centered dummy resistor, a dummy resistor having a smaller resistance value than the dummy resistor, It has switching means for selecting and connecting a dummy resistor having a larger resistance value than the center dummy resistor, controlling the switching means, and first applying a drive pulse current through the design-centered dummy resistor to obtain an electromagnetic force. The first measurement for measuring the discharge flow rate of the pump is performed, and as a result of the first measurement, if the discharge flow rate is within the allowable range of the reference determination value, the dummy resistor at the design center having the same resistance as it is, When the discharge flow rate is smaller than the reference determination value, the small dummy resistor is selected, and when the discharge flow rate is larger than the reference determination value, the large dummy resistor is selectively connected to perform the second measurement. As a result of the measurement, when the small dummy resistor is used as a reference dummy resistor, when the discharge flow rate is smaller than the reference determination value, the first fixed resistor smaller than the small dummy resistor is set to the discharge flow rate. When the discharge flow rate is larger than the reference value, the third fixed resistor is larger than the smaller dummy resistor when the discharge flow rate is larger than the reference value. When the resistor is the dummy resistor of the design center, a fourth fixed resistor having the same resistance value as the dummy resistor of the design center is used as the reference dummy resistor with the large dummy resistor as a reference. In this case, when the discharge flow rate is smaller than the reference determination value, the fifth fixed resistor smaller than the large dummy resistor is used, and when the discharge flow rate is within the allowable range of the reference determination value, the fifth fixed resistor has the same value as the large dummy resistor. When the discharge flow rate is larger than the reference judgment value, the sixth fixed resistor is selected as a seventh fixed resistor which is larger than the large dummy resistor, and the selected first to seventh fixed resistors are selected. One is connected between the first terminal and the third terminal, and a driving pulse current from the discharge flow rate detection driving circuit is applied between the second and third terminals to perform a third measurement, After confirming that the discharge flow rate falls within the allowable range of the reference determination value, the selected fixed resistor is employed (claim 1).

[0013] Thus, by selecting a fixed resistor that keeps the discharge flow rate of the electromagnetic pump within a predetermined range by so-called cut-and-dry measurement in which the first measurement and the second measurement are performed, the characteristics vary. According to the individual characteristics of the electromagnetic pump, it is possible to increase the pass rate of the predetermined flow rate within an allowable range.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a plan view of a fixed resistor selecting device, FIG. 2 is a side view of a state where an electromagnetic pump is mounted on an inspection table of the selecting device, and FIG. 3 is a circuit diagram for selection used in the fixed resistor selecting device. 4, FIG. 4 is a flowchart of the above selection, FIG. 5 is a cross-sectional view of the electromagnetic pump, FIG. 6 is a perspective view of the vicinity of the terminal mounting portion viewed obliquely from above, and FIG. 7 is a plan view of the electromagnetic pump.

First, the electromagnetic pump 1 will be described with reference to FIGS. 5 to 7. The electromagnetic pump 1 has a plunger 3 inserted therein so as to be able to reciprocate in a cylinder 2.
Plunger 3 to support
, An upper spring 4 is provided above, and a lower spring 5 is provided below,
The upper and lower springs 4 and 5 are received on receiving portions 6 and 7 fitted on both ends of the cylinder 2 on opposite sides of the plunger, and the plungers 3 are housed in the cylinder 2 at the receiving portions 6 and 7. . Holes 8 and 9 are formed in the receiving portions 6 and 7.

The cylinder 2 is oil-tightly fitted to O-rings 10 and 27 which are fitted to the upper and lower parts, a discharge nipple 34 and a suction pipe 22 which will be described later.

The plunger 3 has a through hole 11 at its center.
A suction valve 12 and a spring 13 for urging the suction valve 12 are disposed in the through hole 11.

The electromagnetic coil 14 is wound around a bobbin 15 made of resin, and is fitted around the cylinder 2. Between the bobbin 15 supporting the electromagnetic coil 14 and the cylinder 2, an upper magnetic pole cylinder 16 is interposed above the magnetic material and a lower magnetic pole cylinder 17 is interposed below. The bobbin 15
An upper magnetic plate 18 made of a magnetic material is mounted on the upper end side, and a lower magnetic plate 19 made of a magnetic material is mounted on the lower end side.
17 and an outer end thereof contacts an outer plate 30 described below.

The suction pipe 22 is made of a resin or the like, has a through hole 23 formed at the center thereof, and has a flange 24 projecting outwardly upward.
The lower end of the cylinder 2 is inserted in the upper part of the cylinder, and the O-ring 27 keeps oil tight. This suction pipe 22
The suction pipe 22 is assembled by inserting the lower plate 26 from below, engaging with the collar 24, and screwing the outer plate 30 described below with screws 28.

The outer plate 30 is disposed outside the electromagnetic coil 14 and is made of a magnetic material.
0a, 30a, and a flat portion 30b that is laid between the upper portions of the upright portions.
The lower portions of the three raised surfaces 30a, 30a are bent outward at right angles to become attachment portions 30c, 30c.
0c is screwed to the lower plate 26 with the screw as described above. Further, a hexagonal hole 33 is formed in the center of the flat portion 30b of the outer plate 30 to be engaged with a discharge nipple 34 described below.

The discharge nipple 34 has a circular flange 35 on the outer periphery and a hexagonal portion 36 formed in the circumferential direction. A through hole 37 is formed in the inside of the discharge nipple 34 in the axial direction. A discharge valve 38 and a spring 39 are sequentially housed, and a discharge sheet presser 41 provided with a discharge sheet 40 is mounted by being pushed in by an O-ring 42 so as to be kept oil-tight. The discharge nipple 34 is engaged with the hexagonal hole 33 of the outer plate 30, and the discharge sheet retainer 41 comes into contact with the above-described receiving portion 6, thereby forming the downstream passage from the suction valve 12 and the through hole 3.
7 is in a communication state.

As shown in FIG. 6 and FIG. 7, the terminal mounting portion 50 is provided extending from the upper end of the bobbin 15 to the outside of the outer plate 30, and has a rectangular shape. Of terminals 51, 52, 53 are arranged in parallel. The first terminal 51 includes a fixing portion (not shown) mounted on the terminal mounting portion 50, a lead wire connecting portion 51 b for winding a lead wire of the electromagnetic coil 14, and a terminal mounting of the fixed resistor 57. And a groove 51c.

The second terminal 52 has an insertion portion 52a inserted into a connection portion from a drive circuit of a combustor (not shown).
And a fixing part (not shown) attached to the terminal attaching part 50
And a lead wire connection portion 52b for winding the lead wire of the electromagnetic coil 14. Third
The terminal 53 has an insertion portion 53a inserted into a connection portion from a drive circuit of a combustor (not shown), and the terminal attachment portion 50.
, A contact portion 53b of the power supply pin 62, and a terminal mounting groove 53c of the fixed resistor 57. The insertion portion 51 of the first terminal 51
a is not used.

The fixed resistor 57 is obtained by the following selection in order to keep the discharge flow rate of the electromagnetic pump 1 within a predetermined flow rate range. The terminals on both sides are connected to the terminal mounting grooves 51c and 53c. Press-fit connection.

The discharge flow rate of the electromagnetic pump 1 in the above-described configuration, in a pre-designed center resistance, are designed to have a predetermined flow rate, the cause as described above, since the variation in the discharge flow rate occurs, the fixed It is necessary to select a resistor. The selection of the fixed resistor 57 for adjustment is shown in FIGS.
This is performed by a fixed resistor selecting device 58 shown in FIG.

The fixed resistor selecting device 58 is provided on a turntable 76 on which a base 75 is rotatably provided with an inspection table 77 on which 30 electromagnetic pumps 1 can be mounted. Is 10 minutes and is a 20 second step method.

The inspection table 77 includes a presser 78 of the electromagnetic pump 1.
And a box 79 in which a discharge flow rate detection drive circuit 65 is housed. An upright rod 90 that stands upright on a turntable 76 as a presser 78 of the electromagnetic pump is arranged on a guide cylinder 91 so as to be extendable and retractable. And returned downward by a return spring 92.

At the end of the upright rod 90, there is provided a horizontal fixing plate 93, on which a connecting jig 94 having a pneumatic on-off valve and power supply pins 61, 62, 63 are attached. The connection jig 94 with the pneumatic on-off valve contacts the discharge nipple 34 of the electromagnetic pump 1, functions to press the electromagnetic pump 1 through the jig 94, and receives the discharge oil.

The connecting jig 94 with the pneumatic on-off valve includes
Connecting pipe 9 to flow meter (not shown) for measuring discharge flow rate
6 and a predetermined pressure (for example, a reference pressure of 1800 mmA).
The pipe 97 to which the air of q) is added is connected.
The power supply pins 61, 62, and 63 are connected to the lead connection portions 5 of the terminals 51, 52, and 53 of the electromagnetic pump 1.
The driving pulse current from the discharge flow rate inspection driving circuit 65 is supplied by contacting the contact portions 1b, 52b and the contact portion 53b of the power supply pin.

In order to mount the electromagnetic pump 1 on such an inspection table 77, first, air is injected into the pneumatic cylinder 99 to move the upright rod 90 upward, so that the fixing plate 93
And the connection jig 94 are displaced upward. Then, the electromagnetic pump 1 is mounted on the turntable 76 and the suction pipe 22
Into the oil tank 98 and then the pneumatic cylinder 9
When the air inside 9 is discharged, the connection jig 94 and the power supply pins 61, 62, 63 are lowered by the return spring 92, and the connection jig 94 supplies power to the discharge nipple 34 of the electromagnetic pump 1. Pins 61, 62 and 63 are terminals 51 and 5
2, 53 of the lead wire connection portion 51b, 5 2 b and the contact portions 5
3b.

A selection circuit used in the fixed resistor selection device is shown in FIG.
A drive pulse current having the same or a predetermined relationship as a drive circuit (which is incorporated in a combustor and outputs a drive pulse current) is generated between the insertion portions 51a and 52a of the first and second terminals 51 and 52. Via lines 54 and 55.

With respect to the power supply pin 61 connected to the insertion portion 51a of the first terminal 51, three resistors, that is, a dummy resistor 67 (for example, 20) serving as a design center of the electromagnetic pump are provided.
0Ω), a dummy resistor 68 having a smaller resistance value.
(E.g., 120 ohms), and a dummy resistor 69 (e.g., 270 ohms) having a larger resistance value is connected in parallel, and changeover switches 71, 72 for selecting these three resistors 67, 68, 69 are provided. The movable contact of the changeover switch 71 is connected to the dummy resistor 67 at the center of the design at the position indicated by the solid line, and is connected to the small dummy resistor 68 when switched. In the changeover switch 72, the movable contact is connected in series with the changeover switch 71 at the position indicated by the solid line, and is connected to a large dummy resistor 69 when switched.

The changeover switches 71 and 72 include:
Further, a changeover switch 73 is connected in series, and the movable contact is connected to the changeover switch 72 at the position indicated by the solid line. When the movable contact is changed over, the movable contact is connected to the third terminal 53 from the power supply pin 63 and is connected via the line 56. A pulse drive current flows.

The selection of the fixed resistor 57 using the selection device 58 having the above-described configuration is performed according to the flowchart shown in FIG. The electromagnetic pump 1 is mounted on the inspection table 77 of the discharge flow selection device 58. That is, the power supply pins 61, 62, 63 are connected to the respective contact portions 51 b, 52 of the first to third terminals 51 , 52, 53 of the electromagnetic pump 1.
b, 53b.

If contact is made, the process proceeds to step 102, where a drive pulse current is applied to the electromagnetic pump 1 from the discharge flow rate detection drive circuit 65 through the dummy resistor 67 at the center of design. Then, in step 103, the first flow rate measurement is performed at the fifth position in FIG. The measurement time is 6
Seconds. The result of this measurement is immediately displayed on the display 80 shown in FIG. 1, and the reference determination value (for example, 314.0) is displayed.
cc / h ± 4.5%). A flow meter for measuring the flow rate is commercially available, and the flow rate output is measured and integrated with a resolution of 1 msec, and the accumulated average value is converted to cc / hour and displayed.

Further, the process proceeds to step 104, and if it is determined from the comparison with the reference determination value based on the flow rate measured at the first time that the flow rate is smaller than the reference determination value, the process proceeds to step 105 and the changeover switch 71 To switch the dummy resistor 68 (for example, 12
0Ω), and a second flow measurement (6 seconds) is made at step 5 in FIG.

Then, the routine proceeds to step 107, where the discharge flow rate is smaller than the reference judgment value (293.4 to 30).
At 0.7 cc / h), the process proceeds to step 108, where a first fixed resistor 81 (for example, 82Ω) smaller than the small dummy resistor 68 is selected. Then, within the reference determination value (3
00.8 to 308.6 cc / h), the second fixed resistor 68 (for example, 1
20Ω) is selected. Further, when the value is larger than the reference determination value (308.7 to 320.8 cc / h), a large third fixed resistor 83 (for example, 160Ω) is selected.

If it is determined in step 104 that the value is the same as the reference judgment value, the flow advances to step 109 to proceed to the dummy resistor 6.
7 (for example, 200Ω) to be connected.
1 becomes the position of the solid line as it is, and the second
Measurement of flow rate for the second time (310.0 to 318.2 cc / h)
Is performed at the fifth position in FIG. 1 and it is considered that the same result as the previous time is obtained. Therefore, the fourth fixed resistor 84 (for example, 200Ω) having the same value as the dummy resistor at the center of the design is selected. .

If it is determined in step 104 that the value is larger than the reference judgment value, the process proceeds to step 111 in which the changeover switch 42 is switched to be connected to a dummy resistor 68 (for example, 270 Ω) larger than the dummy resistor 67 mainly designed. ,
In step 112, the second flow measurement (6 seconds) is performed at the fifth time in FIG.

Then, the routine proceeds to step 113, where the discharge flow rate is smaller than the reference determination value (304.0-3).
10.0 cc / h), the process proceeds to step 108, where the fifth fixed resistor 85 smaller than the large dummy resistor 69 is set.
(For example, 240Ω) is selected. If the value is within the reference determination value (310.1 to 319.3 cc / h), the sixth fixed resistor 86 equivalent to the large dummy resistor is selected. Furthermore, when it is larger than the reference judgment value (319.4 to
328.3 cc / h), the large seventh fixed resistor 87
(For example, 300Ω).

The first to seventh fixed resistors 81 to 87 selected as described above are used in step 114 to set the fixed resistance mounting grooves 52 c and 53 c of the first terminal 51 and the third terminal 53 of the electromagnetic pump 1. Then, it is press-fitted with a resistor fitting 89 and mounted (at the sixth position). And step 11
Proceeding to step 5, the changeover switch 73 is changed to step 1
At the 16th, the third measurement of the flow rate is performed at the eighth position after the smoothing operation (9 seconds). And step 11
If this discharge flow rate is within the allowable range of the reference measurement value at 7,
OK is displayed on the display 80 as a pass (step 11)
8) In the case of rejection, it is displayed as NG (step 119), the end step 120 is reached, and the flowchart ends.

When the flow rate is smaller than the discharge rate at which the first fixed resistor 81 is selected, a fixed resistor of 40Ω is attached and the determination is made again, and the discharge rate at which the seventh fixed resistor 87 is selected is selected. When the flow rate is larger than the flow rate, 330Ω is attached and the determination is made again. Also, in manufacturing the electromagnetic pump, the pump is manufactured so as to have a predetermined discharge flow rate or more with respect to a drive pulse current supplied from a drive circuit in the combustor, and how many fixed resistors are attached at that time. It is entrusted to the electromagnetic pump manufacturer, and the applicant company has 200 Ω as the design-centered resistance value. In this example, the numerical value in this application is selected.

[0043]

As described above, according to the present invention, in an electromagnetic pump having different characteristics, a fixed resistor for adjustment can be selected by a plurality of measurements, so that the electromagnetic pump is accurate and has little variation. Can be sent to a combustor manufacturer, and a combustor with a low reject rate even when attached to the combustor can be provided.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention and is a plan view of an apparatus for selecting a fixed resistor.

FIG. 2 is a side view showing a state in which the electromagnetic pump is attached to an inspection table of a selection device.

FIG. 3 is a circuit diagram for selection used in an apparatus for selecting a fixed resistor.

FIG. 4 is a flowchart for selecting a fixed resistor in order to set the discharge flow rate of the electromagnetic pump to a predetermined value.

FIG. 5 is a longitudinal sectional view of the electromagnetic pump.

FIG. 6 is a perspective view of the vicinity of a terminal mounting portion of the electromagnetic pump as viewed obliquely from above.

FIG. 7 is a plan view of the electromagnetic pump.

[Explanation of symbols]

 Reference Signs List 1 electromagnetic pump 2 cylinder 3 plunger 14 electromagnetic coil 22 suction pipe 50 terminal mounting part 51 first terminal 52 second terminal 53 third terminal 51a insertion part 52a insertion part 53a insertion part 51c fixed resistor mounting groove 53c fixed Mounting groove for resistor 57 Fixed resistor 58 Selection device 61, 62, 63 Power supply pin 65 Driving circuit for detecting discharge flow 67 Dummy resistor to be the center of design 68 Dummy resistor with small resistance value 69 Dummy resistor with large resistance value Container 71 Changeover switch 72 Changeover switch 73 Changeover switch

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Atsushi Nomura 5-1-1-16 Chiyoda, Sakado City, Saitama Prefecture Inside Nihon Control Kogyo Co., Ltd. (58) Field surveyed (Int. Cl. ⁷ , DB name) F04B 17 / 04 F23K 5/04

Claims (1)

(57) [Claims] A reciprocating plunger disposed in a cylinder, an electromagnetic coil externally fitted to the outside of the cylinder, a check valve provided in a center hole of the plunger, and a reverse valve provided in the cylinder. A third terminal for connecting a fixed resistor between the stop valve and a first terminal connected to both ends of the winding of the electromagnetic coil and a second terminal and the first terminal, respectively.
Wherein a desired drive pulse current is connected and applied between the second terminal and the third terminal from the drive circuit to obtain a desired discharge flow rate. When supplying a drive pulse current from the discharge flow rate detection drive circuit having the same or a predetermined relationship between the first terminal and the second terminal, a design center is applied to one of the first terminal and the second terminal. A dummy resistor, a dummy resistor having a smaller resistance value than the dummy resistor, and switching means for selecting and connecting a dummy resistor having a larger resistance value than the dummy resistor of the design center, and controlling the switching means; First, a drive pulse current is applied through a design-centered dummy resistor to measure the discharge flow rate of the electromagnetic pump, and the first measurement is performed. As a result of the first measurement, the discharge flow rate is within the allowable range of the reference determination value. The dummy resistor in the design center having the same resistance value as it is, the small dummy resistor when the discharge flow rate is smaller than the reference judgment value, and the large dummy resistance when the discharge flow rate is larger than the reference judgment value. The second measurement is performed by selectively connecting the heaters. As a result of the second measurement, when the small dummy resistor is used as a reference dummy resistor, the discharge flow rate is smaller than a reference determination value. A first fixed resistor smaller than the small dummy resistor, a second fixed resistor having the same value as the small dummy resistor when the discharge flow rate is within the allowable range of the reference judgment value, and a discharge flow rate equal to the reference judgment value A third fixed resistor larger than the small dummy resistor when larger than
When the design-centered dummy resistor is used, a fourth fixed resistor having the same resistance value as the design-centered dummy resistor is used. Is smaller than the large dummy resistor when is smaller than the reference judgment value, and a sixth fixed resistor having the same value as the large dummy resistor when the discharge flow rate is within the allowable range of the reference judgment value. When the discharge flow rate is larger than the reference determination value, a seventh fixed resistor larger than the large dummy resistor is selected, and one of the selected first to seventh fixed resistors is connected to the first fixed resistor.
And the third measurement is performed by applying the drive pulse current from the discharge flow rate detection drive circuit between the second and third terminals, and performing the third measurement. A method for manufacturing an electromagnetic pump for fuel supply of an oil combustor, wherein a fixed resistor selected after confirming that the value falls within an allowable range is adopted.