JPS60230574A - Feed oil pump device - Google Patents

Abstract

PURPOSE:To control a pump flow rate to be constant all the time, by using a piezo- ceramic as a driving source for a pump, while detecting a volumetric variation transit value of the piezo-ceramic with a distortion sensor, and feeding the detection signal back to a driving power source of the ceramic. CONSTITUTION:When a plug cock 21 is closed after a liquid is made to fill up a pump chamber 12 out of an injection port 20, an interconnecting member 18 is pushed to the side of a suction check valve chest 5 and thereby it is stabilized, thereat. Under this condition, if voltage is impressed on a piezoelectric element 13, this piezoelectric element 13 is displaced in an axial direction whereby volume in the pump chamber 12 is adjusted for increase or decrease. In consequence, the liquid inside the pump chamber 12 reciprocates in an interconnecting passage, causing the volume of the suction check valve chest 5 to be increased or decreased, so that both check valves 6 and 10 open alternately, thus pumping action ranging from a suction port 2 to a discharge port 3 is produced there. In this case, a transit value of the piezoelectric element 13 is detected by a distortion sensor 30, and a voltage value to be added to the piezoelectric element 13 is controlled so as to cause the output of the distortion sensor 30 to become constant. With this constitution, a pump flow rate is controlled to be constant.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to the field of pumps, and particularly to kerosene-burning refueling pumps which require stability in the flow rate of the pump.

Conventional configuration and its problems A fuel pump used for burning kerosene oil needs to maintain the flow rate at a predetermined value in order to stabilize combustion. Electromagnetic pumps that drive oil by driving a piston with electromagnetic force are currently popular, but there is no way to control the amount of movement of the piston, so once the initial flow rate is set once, the rest changes over time. It has the disadvantage that it cannot respond to changes in flow rate, making kerosene combustion unstable.

Pumps using piezoelectric ceramics have been announced in the past, but due to the poor output power of the piezoelectric ceramics, the characteristics of the pumps change drastically due to load fluctuations, making them unusable.

OBJECTS OF THE INVENTION The purpose of the present invention is to make full use of the advantages of the simple structure of piezoelectric ceramics, while at the same time eliminating the disadvantages of piezoelectric ceramic pumps, and to create a completely new system that can be used in kerosene refueling pumps where flow stabilization is strongly desired. The present invention provides a fuel pump device.

Structure of the Invention A piezoelectric ceramic is used as a drive source for a pump, and at the same time, the amount of change in volume of the piezoelectric ceramic is detected by a separate strain sensor, and the strain sensor signal is fed back to the drive power source of the piezoelectric ceramic. This eliminates the influence of disturbances due to insufficient power, always establishes a constant volume change, and prevents changes in flow rate due to aging.Furthermore, by making good use of the temperature characteristics of the strain sensor, the temperature of kerosene combustion This eliminates the change in the mixing ratio of air and kerosene.

DESCRIPTION OF THE EMBODIMENTS FIG. 1 is a basic configuration diagram of a liquid pump C (hereinafter referred to as pump) using piezoelectric ceramics, in which (a) is a front view, (b) is the I- of (a), It is a side sectional view cut along the I line.

Reference numeral 1 denotes a pump body, which has an inlet port 2 and a discharge port 3 that are integrated in structure. The suction port 2 is fully opened and a valve seat 4 is formed at the other end, and there is a suction check valve chamber 5 on the side of the valve seat 4, and a check valve 6 inside is closed to the valve seat 4 by a spring 7. is pressed in the direction of closing and moves within the suction check valve chamber 5 to open and close the valve seat 4. The suction check valve chamber 5 further communicates with the valve seat 8, and a discharge check valve chamber 9 is formed on the valve seat 8 side, and has the same function and configuration as the suction check valve chamber 5. , a check valve 10, and a spring 11 are provided. The discharge check valve chamber 9 communicates with the discharge port 3. The above two check valves perform a fluid rectification function, similar to check valves normally used in reciprocating pumps. A pump chamber 12 is further formed in the pump body 1, and a piezoelectric ceramic 13 (hereinafter referred to as a piezoelectric element) is connected to a sealing material 14 on the negative side.
While being fluidly sealed from the outside, it is pressed by a lid 15 and fixed to the pump body 1 by screws 16. Lid 1
5 is open at the center, and the piezoelectric element 13 is located only at the outer periphery.
is fixed. The pressure chamber 12 is communicated with the suction check valve chamber 5 through a communication @17, and has a communication member 18 therein. The communication member 18 is provided so as to be slidable in the axial direction with an appropriate gap in the communication passage 17, and has a communication port 19 in the center.

The communication member 18 is connected to the suction check valve chamber 5 or the pump chamber 1.
A suitable stopper is provided to prevent the drawer from falling into the hole.

Further, an injection port 2 is open in the pump chamber 12, and the outside thereof is sealed and sealed by a sealing hole η of a stopper 21.

FIG. 2 shows the piezoelectric element 13, in which (al is a front view, and FIG. 2 is a side sectional view taken along the line ■-■).

The piezoelectric element 13 consists of an elastic metal plate 23 and a ceramic 24, both of which are firmly bonded with an adhesive. An electrode 25 is formed on the circular surface of the ceramic 24, and when a voltage is applied to the electrode 25 and the elastic metal plate 23, the ceramic 24 is displaced in the axial direction. The principle of this displacement is the same as that of piezoelectric buzzers currently on the market, and will therefore be omitted. This piezoelectric element 13 is used in FIG. As shown in FIG. 1, a ceramic 24 is present on the side opposite the pump chamber 12, and the lid 1
It is desirable that the portion pressed by 5 is an elastic metal plate 23. The reason for this is to simplify the configuration of the voltage supply means and to increase the displacement of the piezoelectric element 13, but the details will be omitted.

FIG. 3 shows an embodiment in which a strain sensor is included.

The strain sensor 30 has one end sandwiched between an insulator 31 and is fixed to the lid 15 using a presser metal fitting 32 and a screw 33. The other end is brought into contact with the piezoelectric element 13 so as to be freely movable in the axial direction of the piezoelectric element 13 by the contact member 34, and is assembled so as to transmit the axial movement of the piezoelectric element 13 to the movement of the strain sensor 30. ing.

FIG. 4 shows an example of a strain sensor 30, which is a piezoelectric ceramic 36't bonded to a metal piece 35, and is structurally similar to the piezoelectric element 13. The metal piece 35 has a hole 3 at the tip.
7, into which the contact member is fitted. This distortion,
Sensor 3 (1-1 Deflect within the elastic range of the metal piece 35,
This achieves coupling between the piezoelectric element 13 and the strain sensor 30.

The plug 21 is removed, the pump chamber 12 is filled with liquid (incompressible) through the injection port 20, and the plug 21 is closed.At this time, the communication member 18 is pushed by the injection pressure and pushed toward the suction check valve chamber 5. become stable. Excess liquid flows into the suction check valve chamber 5 through the communication port 19. In this state, an alternating current voltage is applied to the piezoelectric element 13. Power supply not shown. The waveform of the applied alternating current is preferably a sine wave or a rectangular wave. The frequency of alternating current is 2
A range of 0 Hz to 60 Hz is used. When an alternating current voltage is applied, the piezoelectric element 13 is displaced in the axial direction, and the piezoelectric element 13 is displaced in the axial direction.
The liquid inside will reciprocate in the communication path 17. This reciprocating movement of the liquid causes the communication member 18 to also reciprocate. That is, when the liquid flows from the pump chamber 12 to the suction check valve chamber 5 or in the opposite direction, the liquid tries to flow through the communication port 19, but at that time, due to fluid resistance and surface tension of the liquid, the liquid flows through the communication member 18. A force is applied in the direction of the flow. This force causes the communication member 18 to move within the communication path 17 according to the reciprocating motion of the liquid. The effect of this communication member 18 will be described later.

When the liquid in the communication passage 17 moves back and forth, the suction check valve chamber 5
Since the volume of the fluid apparently increases and decreases, when it decreases, the check valve 6 opens in the forward direction, and the check valve 10 closes in the reverse direction, sucking fluid from the suction port 2. On the other hand, when the amount increases, the check valve 6 closes and the check valve 10 opens, so that all of the fluid is discharged to the discharge port 3. This operation occurs continuously, and a pumping action from the suction port 2 to the discharge port 3 occurs. As described above, the movement of the piezoelectric element 13 produces a pumping action.

When a piezoelectric element is used as a pump driver, the following disadvantages arise: Piezoelectric elements have the advantage of low power consumption, but because they consume less power, the load on the pump is small. However, if the voltage changes, the flow rate will change even if the applied voltage remains the same. Such characteristics are applicable to the oil supply pump 3 of a kerosene burner as shown in Fig. 5.
There is a problem when using it as 8. In a combustor that sucks kerosene from a kerosene tank 39, sends it to a mixture vaporizer 40, vaporizes the kerosene, and simultaneously mixes it with air from a fan 41 and burns it completely in a burner 42, the ratio of fuel and air is It is well known that combustion cannot take place unless . Now, in such a system, the load applied to the fuel pump 38 changes every moment due to changes in the kerosene oil level in the kerosene tank 39 and changes in the internal pressure of the mixture vaporizer 40. If the amount of oil in the oil supply pump 38 changes due to this change, stable combustion in the burner 41 cannot be obtained. The liquid pump of FIG. 3 solves this problem as follows. When the pump load changes and the flow rate changes, the amount of movement of the piezoelectric element 13 also changes in proportion to it. In other words, since non-massive liquid is used, the movement of the piezoelectric element 13, which is the driving body of the pump, changes proportionally. The amount is
It determines the flow rate of the pump. Now, since the displacement of the piezoelectric element 13 is detected by the strain sensor 30, the signal of this strain sensor 30 is input into B in Fig. 6, and the reference signal is input into A, so that the signals of A and B always match. By moving the power amplifier 43 using the signal from the comparator 42, the amount of movement of the piezoelectric element 13 can be controlled to be constant by controlling the voltage applied to the piezoelectric element 13. This means that the pump flow rate can also be controlled at a constant level. The above self-controlled flow rate stabilization pump can be supplied, and the burner 41
combustion is stabilized. The strain sensor 30 outputs a larger voltage in proportion to the larger its own strain, and this is determined by the material of the piezoelectric ceramic 36.
Various things are made.

Furthermore, consider what happens when the ambient water temperature changes in Figure 5. As the temperature decreases, the actual power delivered by the 77n 41 tends to increase as the density of the air increases. However, when the oil supply pump 38 sends a constant amount of oil, an imbalance occurs between the air and oil amounts. Since kerosene hardly changes its density due to temperature, the density change of % air has an effect. Therefore, it is desirable that the oil supply pump 38 not always send a constant amount of oil, but increase the amount of oil as the temperature drops. To deal with this, if the output voltage characteristics of the strain sensor 30 shown in Fig. 3 are selected such that the output voltage drops as the temperature drops, feedback will be provided on the electric circuit to obtain a constant output voltage. Therefore, the pump flow rate is
The flow rate can be increased as the temperature decreases, and the degree of increase can be adjusted by arbitrarily selecting the temperature characteristics of the piezoelectric ceramic 36.
The effect of the communication member 18 will be described. At the initial stage of pump installation, pump room 12. The suction check valve chamber 5 can be filled with liquid, but the suction port 2-1 cannot be filled with liquid, so when the pump is driven, air flows into the suction check valve chamber 5. Communication member 1
Without 8, when the volume of the pump chamber 120 contracts, the piezoelectric element 13 has a quick operational response, so a sudden change will occur, and the liquid in the pump chamber 12 will scatter into the air in the suction check valve chamber 5. , air enters the pump chamber 12 to replace it. When air enters the pump chamber 12, since air is compressible, it attenuates the pump action, reducing the pump flow rate, and the correlation between the output voltage of the strain sensor 30 and the flow rate is about to collapse. To prevent this, the communication member 18 is inserted to prevent the liquid from scattering even if the liquid moves rapidly. With the communication member 18, the sudden displacement of the liquid is alleviated by the mass and resistance of the communication member 18, thereby preventing the liquid from scattering.

Effects of the Invention As described above, the oil supply pump device of the present invention provides the following effects.

(1) The configuration includes a feedbank system that detects the amount of displacement of the piezoelectric ceramic that drives the pump and controls the voltage applied to the piezoelectric ceramic to keep the amount of displacement constant at all times, so the load applied to the pump does not change. The pump discharge amount does not change even when the pump discharges, and a constant flow pump can be provided.

(2) Temperature characteristic f of the strain sensor that detects the amount of displacement of the pressure ceramic: Since it has a negative characteristic with respect to the hot water temperature, the ratio of air to fuel in the kerosene burner should be kept constant even if the temperature changes. be able to.

[Brief explanation of drawings]

Fig. 1 (at, b) is a front view and a cross-sectional side view of a pump using piezoelectric ceramic, and Fig. 2 (a), (b) are
) are the front and side views of the piezoelectric ceramic, and Figure 3 (a
), (b) is a front view and a partially sectional side view of a refueling pump device according to an embodiment of the present invention, and FIG. 4(a),
, (b) is a front view and a cross-sectional side view of the strain sensor, FIG. 5 is a block diagram of the kerosene combustion bag, and FIG. 6 is a block diagram of the electrical system of the piezoelectric ceramic drive device. 1...°... Pump body, 2... Suction port, 3...
・・・Discharge port, 6...Suction check valve, 10...
...Discharge check valve, 12...Pump chamber, 1
3... Piezoelectric element, 3o... Strain sensor. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure a Figure 2 & 24 2m==4 Figure 3 a Figure 4 Figure 5 Figure 6

Claims (2)

[Claims] (1) A pump chamber whose internal volume changes with the displacement of a single piezoelectric ceramic, a suction check valve and a discharge check valve connected to this pump chamber, and a power supply device that applies alternating current voltage to the piezoelectric ceramic. The pump is configured with a strain sensor that detects the amount of displacement of the piezoelectric ceramic and outputs an electrical output, and has a feedback control system that controls the alternating current voltage value applied to the piezoelectric ceramic so that the electrical output of the strain sensor becomes constant. Refueling pump equipment. (2) The oil supply pump device according to claim 1, wherein the electrical output characteristic of the strain sensor is set to have a positive characteristic with respect to temperature such that as the temperature decreases, the electrical output decreases with the same strain. .