JPH1018966A - Electromagnetic pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the counter-flow of liquid fuel, improve the suction and supply efficiency of liquid fuel, and stabilize the discharge of liquid fuel in an electromagnetic pump. SOLUTION: During the standing of a pump for its driving, a thrust pin opens a discharge valve as a plunger 37 moves to thereby flow liquid fuel counter by its gravity by way of vertical grooves 9 formed in the inner periphery of a cylinder 10. Which increases the counter-flow of liquid fuel to permit the pump to thereafter quickly suck the liquid fuel on the downstream side to the discharge valve. During stoppage in supplying liquid fuel, the lowermost end of the plunger 37 lies above the lowermost ends of the vertical grooves 9, while during supplying liquid fuel, the lowermost end of the plunger 37 lies below the lowermost ends of the vertical grooves. Which reduces leakage of air and liquid fluid at the normal operation of the pump to improve the suction and supply efficiency of liquid fuel and to stabilize the discharge thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to heating or hot water supply,
The present invention relates to an electromagnetic pump that is used in various combustion devices for cooking and supplies liquid fuel such as white kerosene to a petroleum combustor for consumer use, for example.

[0002]

2. Description of the Related Art Conventionally, in an electromagnetic pump for supplying liquid fuel to a combustion portion of a combustion device such as an oil combustor, an electromagnetic pump for preventing toxicity and odor of combustion exhaust gas due to incomplete combustion at the time of fire extinguishing. Is equipped with a liquid fuel backflow function to prevent dripping of the liquid fuel during fire extinguishing. Such an electromagnetic pump will be described with reference to FIGS.

FIG. 7 is a longitudinal sectional view showing the structure of a conventional electromagnetic pump, FIG. 8 is a transverse sectional view taken along line AA 'of the electromagnetic pump shown in FIG. 7, and FIG. 9 is a transverse sectional view taken along line BB' of the electromagnetic pump shown in FIG. is there.

[0004] In FIG. 7 to FIG.
Has a cylindrical cylinder 32 and a discharge joint 3 provided above the cylinder 32 and having a discharge port 33 at an upper end.
4 and a suction port 3 provided at the lower end of the cylinder 32
5 is provided. The discharge joint 34, the cylinder 32, and the suction cylinder 36 are integrally connected to form a tubular body extending from the suction port 35 to the discharge port 33 through the inside of the cylinder 32.

In the cylinder 32, a free-piston-shaped plunger 37 having a fluid passage and a push-up pin 38 whose lower end is fitted and connected to the plunger 37 are slid by a pair of support springs 39 and 40. It is arranged in a predetermined position so as to reciprocate. This plunger 37
A suction check valve is provided in the inner fluid passage so that the opening of the suction valve seat 41 can be opened and closed while the spherical suction valve 42 is lightly urged by the spring 43 to the suction valve seat 41. ing. Further, a discharge-side check valve configured to open and close the opening of the discharge valve seat 44 in a state where the discharge valve 45 is lightly urged by the spring 46 to the discharge valve seat 44 is provided in the discharge joint 34. ing. Further, the push-up pin 38 is configured so as to be able to push up the bottom of the discharge valve 45 at the tip end, and the connecting portion with the plunger 37 on the opposite side to the tip end has a cross-sectional shape as shown in FIG. And a gap 38 for communicating the inside and outside of the plunger 37 between the base of the cross-shaped portion and the inner diameter of the plunger 37.
a exists.

A coil bobbin 47 is disposed on the outer periphery of the cylinder 32.
Is wound with an electromagnetic coil 48 for generating an electromagnetic force. Inside the coil bobbin 47, the magnetic pole member 4 is provided.
9 and 50, and a yoke 51 as a magnetic path member that forms a magnetic path with the magnetic pole members 49 and 50 is disposed outside the coil bobbin 47 and the electromagnetic coil 48. A terminal board 52 is provided on the coil bobbin 47. Both ends of the electromagnetic coil 48 are connected to the terminal plate 52, a drive pulse is supplied to the electromagnetic coil 48 via the terminal plate 52, and the electromagnetic coil 48 is repeatedly excited by the intermittent current of the drive pulse, and each drive is performed. For each pulse, the plunger 37 generates an electromagnetic force according to the pulse width and pulse peak value. Further, a filter 53 for removing dust and the like from the liquid fuel is provided on the suction port 35 side of the suction cylinder 36.

With this configuration, the plunger 37 is in the equilibrium position due to the antagonism of the pair of support springs 39, 40.
The electromagnetic coil 4 is driven by the rising current of the input drive pulse.
8 is excited to generate an electromagnetic force, the plunger 37
Moves upward in the cylinder 32 against the support spring 39. For this reason, the pressure in the plunger 37 rises,
The suction-side check valve is closed by pressing the suction valve 42 against the suction valve seat 41 to prevent backflow, and the discharge-side check valve is configured such that the inside of the plunger 37 is inserted into the cylinder 32 through the gap 38a. Although it is in communication, the pressure in the cylinder 32 pushes and opens the discharge valve 45 against the spring 46 to discharge the liquid fuel from the discharge port 33 at the upper end.

Next, the electromagnetic coil 48 is not excited by the fall of the input drive pulse, and the plunger 37 is returned to the downward balanced position where the pair of support springs 39 and 40 oppose each other by the urging force of the support spring 39. I will be back. At this time, the pressure in the plunger 37 is reduced, and the suction-side check valve is opened by pushing the suction valve 42 against the spring 43, and the discharge-side check valve is
The discharge valve 45 is pressed against the discharge valve seat 44 side by the low pressure in 2 and is closed, thereby preventing the backflow of the liquid fuel previously discharged through the discharge side check valve,
The liquid fuel in the fuel tank can be sucked through the suction port 35 and the suction side check valve. The liquid fuel is supplied to the combustion part by repeating the suction from the fuel tank and the discharge from the discharge port 33 by the reciprocating motion of the plunger 37 in accordance with the input drive pulse.

Further, when the drive of the electromagnetic pump 31 is stopped, an input drive pulse for moving the push-up pin 38 together with the plunger 37 to the discharge check valve side is input to the electromagnetic coil, so that the ejection at the tip of the push-up pin 38 is performed. The discharge valve 45 of the oil check valve is pushed upward to open to perform an opening operation, and the liquid fuel remaining in the oil feed pipe connected to the discharge port 33 of the electromagnetic pump 31 is discharged from the oil feed pipe to the discharge check valve. Since the suction-side check valve closes the passage inside the cylinder through the valve and inside the plunger, the flow is controlled to flow back along the flow path through a small gap between the plunger 37 and the cylinder 32. . This makes it difficult for the liquid fuel present at the tip of the oil feed pipe facing the combustion section to drip onto the floor or wall surface in the high-temperature combustion section due to this backflow. In addition, it is possible to prevent contamination in the combustion section due to tar as the vaporized residue.

[0010]

In the above-mentioned conventional configuration,
When the drive of the electromagnetic pump 31 is stopped,
When the discharge check valve is opened, it is desired to increase the reverse flow rate of the liquid fuel so that the liquid fuel at the tip of the oil feed pipe is drawn in a short time. And it was necessary to make this gap large. Conversely, if the gap is large, leakage of gas and liquid fuel during normal operation increases, and the center of the push-up pin 38 due to the inclination of the plunger corresponding to the gap also occurs, thereby hindering the movement of the plunger 37. As a result, problems have arisen in the efficiency of suction and supply of the liquid fuel, the stability of the discharge amount, and the like.

The present invention solves the above-mentioned conventional problems. When the driving of the pump is stopped, the reverse flow rate of the liquid fuel is increased so that the liquid fuel at the tip of the oil supply pipe is quickly drawn in, so that the deodorizing and fire preventing effects can be improved. It is an object of the present invention to provide an electromagnetic pump that can exhibit a stable discharge rate with good suction and supply efficiency of a liquid fuel, as well as exhibiting a stable discharge amount.

[0012]

The electromagnetic pump of the present invention comprises:
A plug-like member having a valve reciprocates in a vertically arranged cylindrical member so that the liquid fuel can be supplied upward to feed the liquid fuel to the combustion section. On the other hand, when the liquid fuel supply is stopped, the liquid fuel flows backward. In the electromagnetic pump having a reverse flow function, at least one groove is formed on the inner peripheral surface side of the cylindrical member.
The present invention is characterized in that the liquid fuel can flow backward through the groove when the supply of the liquid fuel is stopped. Preferably, in the electromagnetic pump of the present invention, a plunger having a downstream end opened and a suction check valve provided at an upstream end is equilibrium supported by biasing means from both the upstream and downstream sides. Arranged in the cylinder, a protruding member is arranged between the downstream end of the plunger and the discharge check valve, and the plunger is moved to the top dead center on the downstream side by a control current supplied to the electromagnetic coil. The plunger is moved back to the bottom dead center on the upstream side by the urging means, and the suction check valve is opened at the time of the reciprocation to discharge the liquid fuel sucked into the plunger at the time of the forward movement. By opening a non-return valve and discharging the liquid, when the liquid fuel supply is stopped, by outputting a control current to the electromagnetic coil so that the plunger crosses the top dead center to the downstream side, the displacement of the plunger is caused. The projecting member An electromagnetic pump having a reverse flow function for deodorization and fire prevention, for example, for deodorizing and preventing fire by opening a discharge check valve to reverse liquid fuel, wherein at least one groove is provided on the inner peripheral surface side of the cylinder, and the liquid fuel supply is stopped. Sometimes, the upper end of the groove is located above the upper end of the plunger, and the lower end of the groove is located below the lower end of the plunger. The lower end of the groove is located at a position above the lower end of the groove.

According to this configuration, when the pump is stopped, the control current is output to the electromagnetic coil so that the plunger as the plug-like member crosses the top dead center to the downstream side. Opening the discharge check valve, and allowing the liquid fuel to flow back from its downstream side via the discharge check valve, the cylinder as a cylindrical member, and the groove on the inner peripheral surface of the cylinder by its own weight. Becomes possible. With this, the reverse flow of the liquid fuel is conventionally increased through a small gap between the cylinder and the plunger, but is increased through the groove on the inner peripheral surface of the cylinder. The liquid fuel on the side is quickly drawn in and not discharged, and the deodorizing effect can be further exhibited. Also, at the time of fire extinguishing when an earthquake-resistant device or the like works, the liquid fuel downstream of the discharge check valve is quickly drawn in and not discharged, so that it is safer.

When the supply of liquid fuel is stopped, the lower end of the groove is located at a position lower than the lower end of the plunger, and when the liquid fuel is supplied, the lower end of the groove is located at a position above the lower end of the plunger. Since it is located, it is not necessary to increase the gap between the cylinder and the plunger in order to increase the back flow as in the conventional case, but it is also possible to reduce the gap between the cylinder and the plunger. The leakage of the liquid fuel can be further reduced, and the misalignment of the protruding member due to the inclination of the plunger in this gap is also reduced, so that the liquid fuel suction and supply efficiency is good and the discharge amount is stable. Becomes

In the electromagnetic pump of the present invention, a plunger having a downstream end opened and a suction check valve provided at an upstream end is equilibrium supported by biasing means from both upstream and downstream sides. Arranged in the cylinder, a protruding member is arranged between the downstream end of the plunger and the discharge check valve, and the plunger is moved to the top dead center on the downstream side by a control current supplied to the electromagnetic coil. Forward, the plunger is moved back to the bottom dead center on the upstream side by the urging means,
At the time of the return, the suction check valve is opened and the liquid fuel sucked inside can be discharged at the time of forward movement by opening the discharge check valve. When the liquid fuel supply is stopped, the plunger is discharged. By outputting a control current to the electromagnetic coil so as to pass a point downstream, the deodorant that causes the protrusion to open the discharge check valve and backflow the liquid fuel with the displacement of the plunger. In an electromagnetic pump having a backflow function such as for fire prevention, at least one groove is provided on the inner peripheral surface side of the cylinder, a hole communicating with the open end is provided on the outer peripheral wall of the plunger, and when the liquid fuel supply is stopped, A hole in the plunger and an upper end of the groove communicate with each other, and a lower end of the groove is positioned below a lower end of the plunger, and the plunger is supplied during liquid fuel supply. The lower end of the groove to a position above the lower end and is characterized in that position.

With this configuration, it is possible to increase the reverse flow rate while maintaining good and stable efficiency of suction and supply of the liquid fuel and the discharge amount. In addition, in the case of a configuration in which the plunger is caused to flow backward from the open end to the groove on the cylinder side through the hole, hole machining of the plunger is increased, but this is machining from the outer peripheral surface, which is easy, and The processing length of the groove on the surface side is greatly shortened to facilitate the processing, and the processing accuracy based on the set reverse flow rate is also improved.

Further, preferably, the groove in the electromagnetic pump of the present invention is at least one of a spiral shape and a linear shape along the longitudinal direction of the inner peripheral surface of the cylinder as the cylindrical member.

[0018] With this configuration, the dust in the cylinder escapes into the groove more easily during driving of the plunger than the linear groove, and the spiral groove is more effectively prevented from being caught by the dust between the cylinder and the plunger. obtain.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 1 is an explanatory view showing a state in which an electromagnetic pump according to Embodiment 1 of the present invention is attached to a fuel tank of an oil stove, and members having the same functions and effects as those of the conventional example are denoted by the same reference numerals. And the description is omitted. In FIG. 1, a fuel supply device for an oil stove includes a refueling cartridge 1, a fuel tank 2 in which a liquid fuel F is supplied and stored from the cartridge 1, and a liquid fuel F in the fuel tank 2. An electromagnetic pump 4 that supplies the liquid fuel F from the discharge port 33 to the combustion chamber 3 by positioning the suction port 35 of the suction cylinder 36 and a drive control pulse as a control current is supplied to an electromagnetic coil 48 of the electromagnetic pump 4. And a drive circuit 5 for supplying a fixed amount of liquid fuel F to the combustion chamber 3 and supplying a backflow control pulse as a control current to the electromagnetic coil 48 when the supply is stopped to control the liquid fuel to flow backward. Have been.

An outlet 6 is provided at the lower end of the cartridge 1.
The outlet 6 is normally closed, but when it is mounted on the fuel tank 2, it is pushed open by the projection 7 of the fuel tank 2 to be opened. I have.

The electromagnetic pump 4 is inserted into the mounting hole 8 provided on the upper surface of the fuel tank 2 from the suction cylinder 36 side, and the yoke 51 is mounted with its lower end surface in contact with the upper surface of the fuel tank 2. Has been fixed. The electromagnetic pump 4 has a vertical groove 9 for liquid fuel backflow on the inner peripheral surface side.
A plunger 37 as a free-piston-shaped plug-like member having a fluid passage is arranged in a cylinder 10 as a cylindrical member provided with a reciprocable vertical motion. Liquid fuel can be supplied through the discharge port 33. The four vertical grooves 9 are linearly provided at predetermined intervals. Further, when the supply of the liquid fuel is stopped, the electromagnetic pump 4 pushes the discharge valve 45 of the discharge check valve upward with the tip of the push-up pin 38 as a push-up member to perform an opening operation. Discharge unit 3
It has a deodorizing backflow function of backflowing the liquid fuel remaining in the oil feed pipe 12 connected to 3 by its own weight by the siphon principle, and more liquid fuel flows back through the vertical groove 9. It has become.

Further, the electromagnetic pump 4 has an oil feed pipe 12 connected to the upper end of the discharge joint 34 by a connector 11, and a tip nozzle 1 formed at the tip of the oil feed pipe 12.
2 a is introduced into the combustion chamber 3. This tip nozzle 1
The liquid fuel F supplied into the combustion chamber 3 via the 2a is ignited by an igniter in the initial stage of supply, and thereafter is vaporized in a high-temperature atmosphere in the combustion chamber 3 and burned. The position of the tip nozzle 12a of the oil supply pipe 12 is set to be higher than the position of the oil level in the fuel tank 2 so that the above-described reverse flow when the fuel supply is stopped is possible.

FIG. 2 is a structural view of a main part of the electromagnetic pump 4 of FIG. 1, wherein a is a longitudinal sectional view showing a state when the apparatus is driven, and b is a longitudinal sectional view showing a state when the apparatus is stopped. .
As in FIG. 1, members having the same functions and effects as those of the conventional example are denoted by the same reference numerals, and description thereof will be omitted.

2A and 2B, the plunger 37 reciprocates in the cylinder 10 with a stroke L between the top dead center C1 and the bottom dead center C2 to suck and supply the liquid fuel from the fuel tank 2. The top dead center C1 and the bottom dead center C2 are a downstream position (upper position) and an upstream position (lower position) based on the lower end of the plunger 37 during driving. In particular, the bottom dead center C2 is
This is the equilibrium position of the plunger 37 balanced by the biasing forces of the upper and lower support springs 39, 40. Also, this top dead center C
The opening / closing point above (downstream side) is the electromagnetic coil 48
The tip of the push-up pin 38 is located at the lower end of the plunger 37 in contact with the bottom surface of the discharge valve 45 by supplying a later-described predetermined drive control pulse to the plunger 37. That is, the push-up pin 38 interposed between the plunger 37 and the discharge check valve has a length at which the lower end of the plunger 37 reaches the opening / closing point and the tip of which contacts the discharge valve 45. have. Furthermore, above this opening / closing point (downstream side)
The upper limit point D is the position of the lower end of the mechanism where the plunger 37 can move. As described above, after the driving of the electromagnetic pump 4 is stopped, the check valve 45 is opened by the push-up pin 38 by moving the plunger 37 beyond the top dead center C1 and beyond the opening / closing point further above. As a result, the remaining fuel in the oil pipe 12 is
In this configuration, the backflow is caused by its own weight.

At this time, if the movement of the plunger 3 toward the upper limit point D after exceeding the top dead center C1 is performed at the same speed as during the driving period, the liquid fuel in the cylinder 10 will To the oil supply pipe 1 when the drive is stopped.
Liquid fuel larger than the normal discharge amount is temporarily discharged from the second tip nozzle 12a, and incomplete combustion occurs in the combustion chamber 5 due to insufficient air. As a result, the unpleasant odor becomes remarkable. Therefore, in the present invention, the movement of the plunger 37 to the upper limit point D is gently performed so that the backflow by the siphon action is more effective than the discharge action of the liquid fuel by the movement of the plunger 37. , And the liquid fuel in the oil supply pipe 12 is drawn back into the cylinder 10 as quickly as possible, thereby preventing the liquid fuel from dropping into the combustion chamber 5.

As shown in FIG. 2B, when the liquid fuel supply is stopped (when driving is stopped), the lower end of the plunger 37 is moved to the top dead center C1. When moving to the upper limit point D beyond the upper limit point D, the lower end position of the vertical groove 9 is located below the upper limit point D and is opened, and the upper end position of the vertical groove 9 is set to the plunger 37.
And is open above the upper end. Therefore, when the lower end of the plunger 37 moves to the upper limit point D beyond the open / close point when the liquid fuel supply is stopped, the tip of the push-up pin 38 pushes up the discharge valve 45 to open the oil supply pipe 12 and the cylinder 10. And a vertical groove 9 opened at the upper and lower portions of the plunger 37.
, The inside of the pump portion of the cylinder 10 and the inside of the suction cylinder 36 can be communicated, and the liquid fuel flows back from the oil supply pipe 12 through the inside of the pump portion of the cylinder 10, the vertical groove 9 and the inside of the suction tube 36 by its own weight. Will be. In addition, top dead center C1
When supplying the liquid fuel reciprocating with the stroke L between the stroke and the bottom dead center C2, the lower end of the plunger 37 is not positioned higher than the lower end of the vertical groove 9;
However, the upper and lower portions are not opened through the vertical grooves 9 and come off. As a result, it is possible to obtain a stable and stable discharge amount with good liquid fuel suction and supply efficiency.

FIG. 3 is a circuit diagram showing a configuration example of the drive circuit 5 of FIG. 3, a commercial AC power supply 22 is connected to one end of a power supply unit 21 and an electromagnetic coil 4 is connected to the other end.
8 is connected to the ground via a series circuit of the transistor 8 and the transistor Q, and converts the commercial AC power supply 22 into a DC voltage of a required level V (v) and outputs the DC voltage to the electromagnetic coil 48. Also,
Diodes D connected to both ends of the electromagnetic coil 48 are protection diodes that regulate reverse current. Further, the microcomputer 23 to which the power supply unit 21 and the switch SW1 for instructing driving / stopping are connected, and the base of the transistor Q is connected via the base resistor R for limiting the base current, the microcomputer 23 operates. And has a control program, a timer, and the like therein, and outputs a control signal to the base of the transistor Q based on the ON / OFF of the control program, the timer, and the switch SW1.

The operation of this configuration will be described below. FIG. 4 is a time chart for explaining an example of the operation of the drive circuit 5 of FIG. 3. A plurality of cycles described later are three in FIG. 4 for convenience of illustration, but the plurality of cycles is three.
The period is not limited to the period (the period of three drive pulses a), but may be set to at least two periods. First, as shown in FIG.
Is turned on, a drive pulse a as an input control pulse is output from the output terminal P of the microcomputer 23.
The transistor Q is turned on by the rising current of the drive pulse a, and an exciting current e as a drive control pulse of a predetermined level flows from the power supply unit 21 through the electromagnetic coil 48 and the transistor Q to excite the electromagnetic coil 48.
As a result, the plunger 37 receives the suction force and moves upward from the equilibrium position (bottom dead center C2) of the pair of support springs 39 and 40 against the support spring 39 at the time t3. To the top dead center C1. As a result, the pressure in the plunger 37 rises, and the suction-side check valve is pressed against the suction valve seat 41 to close, thereby preventing backflow. The inside of the cylinder 37 communicates with the cylinder 10 through a gap 38a, but the pressure in the cylinder 10 presses the bottom surface of the check valve 45, and the discharge valve 4 is pressed against the spring 46.
5 is pushed open to open, and the liquid fuel is discharged from the discharge port 33 at the upper end.

Next, at time t3, when the excitation of the electromagnetic coil 4 by the excitation current e is completed, the plunger 37 is moved from the top dead center C1 to the position below the equilibrium position during the excitation suspension period T2 by the urging force of the support spring 39. It will return to return to the dead center C2. At this time, the pressure in the plunger 37 decreases, and the suction-side check valve is opened by pushing open the suction valve 42 against the spring 43, and the discharge-side check valve is controlled by the low pressure in the cylinder 10. As a result, the discharge valve 45 is
By closing the liquid fuel in the oil feed pipe 12 discharged through the discharge-side check valve the last time, the liquid fuel in the fuel tank 2 is prevented from flowing back through the suction port 35 by being closed by being pressed to the side. Further, suction can be performed via a suction-side check valve. Thereafter, the plunger 37 is excited in the next cycle by the next drive pulse a after reaching the bottom dead center C2. Therefore, during the driving period of the electromagnetic pump 4, the plunger 37
Indicates the vertical displacement f of the saw blade over time. By the reciprocating motion of the plunger 37 in accordance with the drive pulse a, the suction from the fuel tank 2 and the discharge unit 3 are performed.
The liquid fuel is supplied to the combustion unit 3 by repeating the discharge from the combustion unit 3. When the stroke L between the top dead center C1 and the bottom dead center C2 of the normal plunger 37 is vertically driven, the tip of the push-up pin 38 does not hit the bottom surface of the check valve 45.

Further, at time t4, the switch SW1 is turned off to stop the operation of the electromagnetic pump 4 to stop the supply of the liquid fuel and extinguish the oil stove. At this time, the microcomputer 23 operates the switch SW1
Is turned off, the output of the drive pulse a is continued for a plurality of cycles set in advance using a timer. That is, when the drive pulse a immediately after the switch SW1 is turned off rises at the time t5 and falls at the time t6, the pulse width from the output terminal P of the microcomputer 23 becomes shorter than the drive pulse a at the time t7 after the period T31. , A first holding pulse a1 having a short cycle is output. The period T31 at this time is set so as to coincide with the period from time t6 when the exciting current e becomes the high level H to time t7 when the exciting current e becomes the low level L.

Further, at time t7, the position of the plunger 37 that has reached the top dead center C1 can be maintained by the subsequent first holding pulse a1. That is,
If the period T31 is shortened earlier than the time point t7, t7
The plunger 3 will exceed the top dead center until the time point is reached. Conversely, if the period T31 is extended to be later than the time point t7, the plunger 37 will drop to a position lower than the top dead center C1 and the plunger 3 will fall. Will cause a position change. Also, the pulse width τ9 of the first holding pulse a1
And the period τ12 are set such that the plunger 37 can be held at the position of the top dead center C1.

Further, at time t9, the driving pulse a is output, and the plunger 37 further rises from the top dead center C1. The plunger 37 that has reached a predetermined position further above the top dead center C1 can be maintained by the subsequent first holding pulse a2. That is, if the period T32 is shortened earlier than the time point t11, the plunger 37 will exceed the predetermined position before reaching the time point t11. Conversely, if the time period T32 is extended to be later than the time point t11, the plunger 37 As a result, the plunger 37 descends to a position lower than the predetermined position, causing the plunger 37 to change its position. Also, the pulse width τ2 of the second holding pulse a2
1 and the period τ22 are set so that the plunger 37 can be held at the predetermined position, and t1 after the period T32
At one time, a second holding pulse a2 having the same pulse width as the first holding pulse a1 and a shorter cycle is output from the output terminal P of the microcomputer 23.

Further, at time t13, the drive pulse a is output, and the plunger 37 further rises to reach the upper limit point D beyond the opening / closing point. The plunger 37 reaching the upper limit point D can be maintained by the subsequent third holding pulse a3. That is, the period T33 is set to t1
If the time is longer than five times, the plunger 37 descends to a position lower than the upper limit position D, and the position of the plunger 37 fluctuates. The pulse width τ31 and the period τ32 of the third holding pulse a3 are set so that the plunger 37 can be held at the upper limit position D. At the time t15 after the period T33, the second end from the output terminal P of the microcomputer 23 A third holding pulse a having the same pulse width as the holding pulse a2 and having a shorter cycle than this.
3 is output.

As described above, the movement of the plunger 37 to the upper limit point D is gradually performed gradually when the pump stops, including the case where the oil stove is overturned due to an earthquake or the like and the fire prevention device is activated. The backflow by the action of the siphon can be dominant over the discharge action of the liquid fuel by the movement of the push-up pin 38, and the push-up pin 38
The tip end of the cylinder pushes up the discharge valve 45 to open, thereby connecting the inside of the oil supply pipe 12 and the inside of the pump section of the cylinder 10, and the inside of the pump section of the cylinder 10 and the suction tube The liquid fuel can flow back from the oil feed pipe 12 through the pump section of the cylinder 10, the vertical groove 9, and the suction cylinder 36 by its own weight. Thus, the reverse flow of the liquid fuel through the small gap between the cylinder 32 and the plunger 37 in the related art can be increased through the gap and the vertical groove 9, and the oil feed pipe can be increased. The liquid fuel at the tip end of the nozzle 12 can be quickly drawn in, so that the deodorizing effect can be more exerted, which is safer. Further, dust in the cylinder 10 escapes into the vertical groove 9 during driving of the plunger 37, so that the dust in the cylinder 10 can be prevented from being caught. Further, by providing the vertical groove 9 on the inner peripheral surface of the cylinder 10, the cylinder 10 and the plunger 37 are provided.
And the frictional resistance with the plunger 37 is reduced, and the movement of the plunger 37 is improved.

When supplying the liquid fuel in which the plunger 37 reciprocates with the stroke L between the top dead center C1 and the bottom dead center C2, the lower end of the plunger 37 is positioned higher than the lower end of the vertical groove 9. There is no possibility that the plunger 37 is opened and removed through the vertical groove 9 at the upper and lower portions thereof. As a result, it is not necessary to increase the gap between the cylinder 32 and the plunger 37 to increase the backflow as in the related art.
7, the leakage of gas and liquid fuel during normal operation can be reduced, and the misalignment of the push-up pin 38 due to the inclination of the plunger in the gap can be reduced. The efficiency of suction and supply of the liquid fuel is good, and a stable discharge amount can be obtained.

(Second Embodiment) In the first embodiment, the vertical groove 9 is provided only on the cylinder 10 side. However, in the second embodiment, a groove is provided on the inner peripheral surface side of the cylinder, and the outer wall side of the plunger is provided. By providing a hole communicating with the inside of the cylinder, the length of the groove on the inner peripheral surface side of the cylinder can be made shorter, which facilitates the machining.

FIG. 5 is a structural view of a main part of an electromagnetic pump according to Embodiment 2 of the present invention, wherein a is a vertical cross-sectional view showing a state when the pump is driven, and b is a vertical cross-sectional view showing a state when the drive is stopped. FIG. 6 is a partial external view of the plunger of FIG. Note that members having the same functions and effects as those in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted.

5 and 6, the plunger 25
The outer peripheral wall is provided with a hole 26 communicating with the inside thereof, and the outer peripheral surface of the outer peripheral wall is provided with the hole 26 and an annular groove 27 communicating with the hole 26 for one round. Four vertical grooves 29 for backflow are provided on the inner peripheral surface of the cylinder 28 at predetermined intervals on the inner peripheral surface of the cylinder 28. These annular groove 27 and longitudinal groove 2
9 is the plunger 25 when the liquid fuel supply is stopped.
Of the plunger 25 with respect to the upper position of the
6 and the annular groove 27 or at a position higher than them, and the lower end thereof is at a position lower than the lower end of the plunger 25. In this case, as in the first embodiment, the lower end of the plunger 25 is at the time of supplying the liquid fuel in which the plunger 25 reciprocates along the inner peripheral surface of the cylinder 28 with the stroke L between the top dead center C1 and the bottom dead center C2. The portion is not located above the lower end of the vertical groove 29, and the plunger 25 does not open through the vertical groove 29 at the inside and at the lower end thereof.

With this configuration, the hole 26 of the plunger 25
And the number of machining of the annular groove 27 increases, but this is easy from machining from the outer peripheral surface, and the length of the vertical groove 29 on the inner peripheral surface side of the cylinder 28 can be greatly shortened. It becomes easier and the processing accuracy is improved.

In the first and second embodiments, four linear grooves 9 or 29 are provided at predetermined intervals on the inner peripheral surface of the cylinder 10 or 28, but may be four or more or less. The reverse flow rate is determined by the total cross-sectional area of the vertical grooves 9 or 29, and the reverse flow rate is the same if the total cross-sectional area is the same even when a plurality of narrow vertical grooves 9 or 29 and one thick vertical groove 9 or 29 are used. Will be the same. Further, instead of such a linear vertical groove 9 or 29, a spiral (spiral) groove along the longitudinal direction of the inner peripheral surface of the cylinder 10 or 28 may be used. In this case, at the time of spiral groove machining, the groove can be easily machined only by pulling the inner peripheral surface of the rotating cylinder member against the cutting tool. Also, in the case of this spiral groove, the linear vertical groove 9 or 29 is used.
As in the case of (1), a plurality of grooves or a single groove may be used. In short, the reverse flow rate is determined by the total cross-sectional area of the groove.
Further, the effect of preventing dust from getting into the cylinder 10 or 28 is better in the case of a spiral (helical) groove than in the case of the linear vertical groove 9 or 29.

[0041]

As described above, according to the present invention, when the liquid fuel supply is stopped, the projection-like member opens the discharge check valve with the displacement of the plunger as the plug-like member, and the inner peripheral surface of the cylinder is closed. To allow the liquid fuel to flow back under its own weight through the groove,
The reverse flow rate of the liquid fuel can be increased, and the liquid fuel on the downstream side of the discharge check valve can be quickly drawn in, so that the deodorizing and fire preventing effects can be further exhibited.

The lower end of the groove is located below the lower end of the plunger when the liquid fuel supply is stopped, and the lower end of the groove is located above the lower end of the plunger when the liquid fuel is supplied. Because of the position, the leakage of gas and liquid fuel during normal operation can be reduced, and the misalignment of the protrusion member due to the inclination of the plunger in this gap is also reduced. And a stable and stable discharge amount.

Further, in the case of a structure in which the flow is made to flow backward from the open end of the plunger to the groove on the cylinder side via the hole, the processing length of the groove on the inner peripheral surface side of the cylinder is greatly shortened, and the processing is facilitated. In addition, the processing accuracy based on the set reverse flow rate can be improved.

Furthermore, during driving of the plunger, dust in the cylinder can easily escape into the spiral and linear grooves, thereby preventing the cylinder and the plunger from being caught by dust.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a state in which an electromagnetic pump according to a first embodiment of the present invention is attached to a fuel tank of an oil stove.

FIGS. 2A and 2B are configuration diagrams of a main part of the electromagnetic pump 4 of FIG. 1, wherein a is a vertical cross-sectional view showing a state at the time of driving, and b is a vertical cross-sectional view showing a state at the time of stopping the driving.

FIG. 3 is a circuit diagram showing a configuration example of a drive circuit 5 of FIG.

FIG. 4 is a time chart for explaining an example of the operation of the driving circuit 5 of FIG. 3;

FIG. 5 is a configuration diagram of a main part of an electromagnetic pump according to a second embodiment of the present invention, in which a is a vertical cross-sectional view showing a state when the pump is driven, and b is a vertical cross-sectional view showing a state when the drive is stopped. is there.

6 is an external view of a main part of the plunger 25 of FIG.

FIG. 7 is a longitudinal sectional view showing a configuration of a conventional electromagnetic pump.

8 is a cross-sectional view of the electromagnetic pump of FIG. 7 taken along line AA '.

9 is a cross-sectional view of the electromagnetic pump of FIG. 7 taken along the line BB '.

[Explanation of symbols]

 Reference Signs List 4 electromagnetic pump 5 drive circuit 9, 29 vertical groove 10, 28 cylinder (cylindrical member) 23 microcomputer 25, 37 plunger 26 hole 27 annular groove 38 push-up pin (projection member) 39, 40 support spring 41 suction valve seat 42 Intake valve 43, 46 Spring 44 Discharge valve seat 45 Discharge valve 48 Electromagnetic coil C1 Top dead center C2 Bottom dead center Q Transistor

Claims (4)

[Claims] 1. A plug-like member having a valve reciprocates in a vertically arranged cylindrical member so that liquid fuel can be supplied upward so as to feed liquid fuel to a combustion section. An electromagnetic pump having a backflow function of backflowing liquid fuel, wherein at least one groove is provided on the inner peripheral surface side of the cylindrical member, and the liquid fuel can flow back through the groove when the liquid fuel supply is stopped. An electromagnetic pump characterized in that: 2. A plunger having a downstream end opened and a suction check valve provided at an upstream end is disposed in a cylinder while being equilibrium supported by biasing means from both upstream and downstream sides. A protruding member is disposed between a downstream end of the plunger and a discharge check valve, and the plunger is moved forward to a top dead center on the downstream side by a control current supplied to an electromagnetic coil. The plunger is moved back to the bottom dead center on the upstream side by the biasing means, and the return check valve is opened at the time of the return, and the discharge check valve is opened at the time of forward movement of the liquid fuel sucked inside. By outputting a control current to the electromagnetic coil so that the plunger crosses the top dead center downstream when the liquid fuel supply is stopped,
An electromagnetic pump having a backflow function in which the projection-like member opens the discharge check valve in accordance with the displacement of the plunger and causes the liquid fuel to flow backward, wherein at least one groove is provided on the inner peripheral surface side of the cylinder. When the liquid fuel supply is stopped, the upper end of the groove is located above the upper end of the plunger, and the lower end of the groove is located below the lower end of the plunger, and An electromagnetic pump wherein the lower end of the groove is located above the lower end of the plunger when supplying liquid fuel. 3. A plunger having a downstream end opened and a suction check valve provided at an upstream end is disposed in a cylinder while being balanced and supported by urging means from both upstream and downstream sides.
A protruding member is disposed between a downstream end of the plunger and a discharge check valve, and the plunger is moved forward to a top dead center on the downstream side by a control current supplied to an electromagnetic coil. The plunger is moved back to the bottom dead center on the upstream side by the biasing means, and the return check valve is opened at the time of the return, and the discharge check valve is opened at the time of forward movement of the liquid fuel sucked inside. By outputting a control current to the electromagnetic coil so that the plunger crosses the top dead center to the downstream side when the liquid fuel supply is stopped, the projecting member is moved along with the displacement of the plunger. An electromagnetic pump having a backflow function for backflowing liquid fuel by opening a discharge check valve, wherein at least one groove is provided on the inner peripheral surface side of the cylinder, and the groove communicates with the outer peripheral wall of the plunger at the open end. A hole is provided, and when the liquid fuel supply is stopped, the hole of the plunger and the upper end of the groove communicate with each other, and the lower end of the groove is positioned below the lower end of the plunger. An electromagnetic pump wherein the lower end of the groove is located above the lower end of the plunger during liquid fuel supply. 4. The electromagnetic pump according to claim 1, wherein the groove is at least one of a spiral shape and a linear shape along a longitudinal direction of the inner peripheral surface.