JPH01280694A - Piezoelectric vibrator pump device - Google Patents

Abstract

PURPOSE:To improve reliability and provide an increased life and to reduce cost and keep stability of flow rate, by providing a vibrator for control which outputs an electric output responding to the change in volume of a pump chamber adapted to control an AC voltage to be applied on a vibrator for drive. CONSTITUTION:Inflow of liquid to a pump chamber 1 and outflow of liquid from the pump chamber 1 are caused through oscillation of a vibrator 2 for drive, and liquid fed with a force is decided by oscillation. A voltage generated at a vibrator 15 for control proportions a pressure in the pump chamber 1, and a proportional relation is also established between a pressure in the pump chamber 1 and a delivery amount. Thus, by controlling a voltage applied on the vibrator 2 for drive so that a voltage generated at the vibrator 15 for control is adjusted to a specified value, and a control means 11 receives a voltage from the vibrator 15 for control and controls an AC voltage to the vibrator 2 for drive so that the voltage is adjusted to a specified value.

Description

[Detailed Description of the Invention] [Industrial Application Field'] The present invention relates to a minute flow rate pump that requires stability and control of the flow rate. The present invention relates to a piezoelectric vibrator pump device.

[Conventional technology]

A pump device of this type is disclosed in Japanese Patent Laid-Open No. 60-230574. FIG. 2 shows a pump device similar to that shown in this publication. In FIG. 92, (1) is a pump chamber, which is formed in a recessed portion of the main body with an open upper end. (21 is a piezoelectric vibrator placed so as to close one side of this pump chamber. 9 A disk-shaped metal plate (2a) with elasticity, a circular piezoelectric ceramic plate (2b) attached to this metal plate, and The peripheral edge of the metal plate (2a) is inserted into the groove formed in the side wall of the main body, and the O-ring (3) is formed from the electrode (2C) formed on the top surface of the ceramic plate. This piezoelectric vibrator (2
), an AC voltage is applied between the metal plate (2a) and the electrode (2C).

When a +' voltage is applied to the electrode (2c) side, the ceramic plate (2a) expands in the radial direction due to the inverse piezoelectric effect, and the piezoelectric vibrator (2) as a whole deforms into an upwardly convex shape.
When a negative voltage is applied to the ceramic plate (2C) side, the ceramic plate (2C)
C) contracts in the radial direction, and the piezoelectric vibrator (21) deforms downwardly as a whole. (4) is a suction check provided between the pump chamber (2) and the suction port (5). In the valve chamber, a VC is provided in the main body, and a check valve (6) is installed inside the chamber.(7) is a valve chamber that connects the pump chamber f11 and the discharge port (8).
) is a discharge check valve chamber provided within the main body, and a check valve (9) is provided within the chamber. The holder is a strain sensor having the same configuration as the piezoelectric vibrator (21), and one end is a metal plate (+) fixed to the main body.
Oa), piezoelectric ceramic plate (10b), and electrode (10C)
and a contact (+od) fixed to the other end of the metal plate (10a) and brought into contact with the piezoelectric vibrator (2).The metal plate (10a) and the electrode (10
A voltage corresponding to the deformation is extracted from c).

02 is a control means that applies an AC voltage to the upper 2 piezoelectric vibrators (2) and feedback-controls the AC voltage in response to the output electric ratio from the strain sensor (1CI);
Reference numeral 1 denotes a liquid reservoir in which a liquid such as petroleum is stored, and is connected to the suction check valve chamber (4) through a pipe 0.

Next, the operation of the piezoelectric vibrator pump device configured in this manner will be explained. First, liquid is injected into the pump chamber (1). Then, when the electrical starch is applied, an AC voltage is supplied from the control means ti11 to the piezoelectric vibrator (2). When a positive voltage is applied to the electrode (2C) of the piezoelectric vibrator (2), the ceramic plate (2b) extends in the radial direction, and the piezoelectric vibrator (2) as a whole deforms into an upwardly convex shape. As a result, the pressure inside the pump chamber (1) decreases, causing the discharge valve (
9) closes and the suction valve (6) opens.

Liquid reservoir 0? The liquid will flow into the pump chamber (1) through the pipe (131).At the next moment, the AC
When the voltage is reversed and a negative voltage is applied to the electrode (2C).

The ceramic plate (2b) shrinks in the radial direction and the piezoelectric vibrator (2)
will be deformed in a downward convex manner as a whole. the result,
Since the pressure in the pump chamber (1) increases, the suction valve (6) closes and the discharge valve 19) opens, so that the liquid in the pump chamber (1) is pumped through the pipe H toward the vaporizer. become. In this way, depending on the amplitude of the piezoelectric vibrator (2), the pump chamber (
1) Liquid flows into the pump chamber (1) and liquid flows out from the pump chamber (1), and the flow rate of the pumped liquid is determined by the amplitude described above. Therefore, in this pump device, the amplitude of the piezoelectric vibrator (2) is detected by the strain sensor (1CI), and this amplitude amount is fed back to the control means (+1) as an electrical output, and the amplitude from the control means (01) is The AC voltage is adjusted to keep the flow rate of liquid pumped constant.

[Problem to be solved by the invention]

However, in the conventional pump device configured as described above, the contactor (1od) of the strain sensor a1 must always be in contact with the center portion of the ceramic plate (2b) of the piezoelectric vibrator (2). As a result, assembly and adjustment are complicated, and extra stress is applied to the central part of the ceramic plate (2b), causing damage to the ceramic plate (2b) after long-term use.
b) had the problem of cracking.

This invention has been made in view of the above points, and aims to provide a piezoelectric vibrator pump device that is highly reliable and has a long service life, is inexpensive, and can maintain a stable flow rate. be.

[Means to solve the problem]

The piezoelectric vibrator pump device according to the present invention includes a piezoelectric vibrator pump device, which is disposed on the other side of the pump chamber opposite to one side on which the drive vibrator is disposed, and for controlling the AC voltage applied to the drive vibrator. A control vibrator is provided that outputs an electrical output according to the volume change of the pump chamber. [Function] The control vibrator of the present invention detects the volume change of the pump chamber directly on one surface. Therefore, it does not break even during long-term use, and outputs a large electrical output with high reliability.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG. 1. In FIG. 2, (1) is a pump chamber formed in the center of a substantially donut-shaped main body with two open ends. (2) is arranged on one side of this pump room,
This drive vibrator increases or decreases the volume inside the pump chamber by applying an AC voltage, and is the same as the piezoelectric vibrator of the conventional example described above, and is composed of a metal plate (2a) and a piezoelectric ceramic plate (2b).
) and an electrode (2C), the peripheral edge of the metal plate (2a) is inserted into a groove formed on the upper part of the inner wall of the main body, and is sealed and fixed with a Q IJ song 3). There is. +151 is disposed on the other side opposite to one side on which the drive vibrator (2) of the pump chamber (1) is disposed, and outputs an electrical output according to the volume change of the pump chamber (2). It is a control vibrator having the same configuration as the drive vibrator (2), and is formed from a metal plate (+Sa), a ceramic plate (15b), and an IT pole (15C). The above metal plate (
The peripheral edge of +5a) is inserted and sealed and fixed with an O-ring αG. However, the rigidity of the control vibrator aS is greater than the rigidity of the drive vibrator (2).

Next, the operation of the piezoelectric vibrator pump device configured in this way will be explained. First, as an initial state, the pump chamber fi
+ is injected with liquid. and.

When the illumination is turned on, AC voltage is supplied from the control means αB to the driving vibrator (2). When a voltage of 10 is applied to the electrode (2C) of the driving vibrator (2), the ceramic plate (2b)
extends in the radial direction, and the drive vibrator (2) as a whole is deformed into an upwardly convex shape. At this time, the control vibrator 09 is also made of a ceramic plate (+sb
) is contracted in the radial direction, and the electrode (15C
) a negative voltage is generated. On the other hand, in terms of rigidity, the control oscillator (+9) has a larger υ than the drive oscillator (2), so the amount of upward deformation is small.

As a result, the volume of the pump chamber (1) increases. Therefore.

Since the pressure in the pump chamber (1) decreases, the discharge valve (9) closes and the suction valve (6) opens, so that liquid flows from the liquid reservoir 0z into the pump chamber (1) via the knob 131. That will happen. In the next moment, the AC voltage reverses and the electrode (
2C), when a negative voltage is applied to the ceramic plate (2B
) shrinks in the radial direction, and the piezoelectric vibrator (21) as a whole deforms into a downward convex shape.At this time, the pressure inside the pump chamber (1) increases, and the control vibrator aS also deforms into a downward convex shape. Therefore, the ceramic plate (+sb) extends in the radial direction and connects the electrode (+5
A voltage of 10 is generated at C). On the other hand, due to the difference in rigidity between the two vibrators (2) and Kasumi, the volume inside the pump chamber (1) decreases and the pressure increases, so the suction valve (6) closes and the discharge valve (9) opens. Therefore, the liquid in the pump chamber (1) will be pumped towards the vaporizer via the pipe (141).In this way, depending on the amplitude of the piezoelectric vibrator (2), the liquid in the pump chamber (1) will be pumped through the pipe (141). The flow rate of the liquid to be pumped is determined by the above amplitude. The voltage generated at a51 is proportional to the pressure in the pump chamber +11, and there is also a relative relationship between the pressure in the pump chamber +1) and the discharge amount. Therefore, by controlling the voltage applied to the drive vibrator (2) so that the voltage generated across the control vibrator (1) becomes constant, the ejection amount can be kept constant, and the control means (Ill. receives the voltage from the control oscillator 0 and controls the AC voltage to the drive oscillator (2) so that this voltage becomes constant.This control by the control means flllK is performed in advance by .

Perform calibration to determine the discharge amount and control vibrator (1
This is done based on understanding the relationship with the voltage generated at 51, and the discharge amount is set to an arbitrary value.
The control means determines the voltage value from the control vibrator a9 based on that value, and controls the AC voltage to the drive vibrator (21) so that the voltage value can be maintained at this determined voltage value, so that the discharge amount is always constant. It is something that is kept.

In the above embodiment, two piezoelectric vibrators (2) (1
Although the ceramic plate is glued to one side of the plate, it is also possible to glue the ceramic plate to both sides.

The material to be pumped is not limited to liquid, but may also be gas.

〔Effect of the invention〕

As described above, the present invention provides the above-mentioned AC voltage disposed on the other surface opposite to one surface on which the drive vibrator of the pump chamber is disposed, and for controlling the AC voltage applied to the drive vibrator. A control vibrator is installed that outputs electrical output according to volume changes in the pump chamber.

It has the advantage of being able to withstand long-term use as a control vibrator, outputting a large electrical output, and achieving high reliability.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention, and FIG. 2 is a diagram showing a conventional piezoelectric vibrator pump device. In the figure, (1) is the pump chamber, and (2) is the drive vibrator. (5) is the suction port, (6) is the suction valve, (8) is the discharge port, (
9) is a discharge i, +il+ is a control means, and 9) is a control vibrator. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] A piezoelectric vibrator for driving is arranged on one side of the pump chamber and increases/decreases the volume inside the pump chamber by applying an alternating current voltage; a control vibrator that outputs an electric output according to the control vibrator, a control means that receives the electric output of the control vibrator and changes the value of the AC voltage according to the electric output, and between the pump chamber and the suction port. A piezoelectric vibrator pump device comprising a suction valve provided between the pump chamber and the discharge port, and a discharge valve provided between the pump chamber and the discharge port.