JPS61265397A - Fluid driving apparatus - Google Patents

Abstract

PURPOSE:To maintain the max. working efficiency by controlling the frequency of a driving electric wave by a controller so that the vibration state in the space formed by a case body or the inside of a driving tube by the signal supplied from a pressure sensor installed into the case body or the driving tube. CONSTITUTION:When the Helmholtz's resonance frequency of the captioned apparatus is varied by the variation of the fluid temperature, etc., the frequency of an electric power apparatus 20, namely the vibration frequency of a vibrating plate 13 is kept constant, and the resonance conditions are broken, and the pressure in a space 11 lowers. Therefore, the output signal of a pressure sensor 21 lowers, and the frequency of the electric power apparatus 20 is controlled by a controller 22 through the utilization of the reduction portion of the signal. Therefore, when control is carried out so that the reduction portion of the above-described signal becomes zero, and the level of the output signal of the pressure sensor 21 becomes max., a driving tube 12 vibrates in the accord with the Helmholtz's resonance frequency, and the driving efficiency of fluid can be maintained to the max.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION This invention relates to a fluid drive device for conveying fluids such as gases and liquids.

2. Description of the Related Art In order to obtain an inexpensive fluid drive device, it is desirable to use reciprocating motion as the drive source. The device shown in FIG. 2, which uses reciprocating motion as a driving source, satisfies the Helmholtz resonance condition with a space 11 with a volume of V, a cross-sectional image, and a drive tube 12 with a length L. Vibration plate 13 attached to body 1o
When driven at a frequency of 10 determined by equation (1), the columnar fluid 19 inside the drive tube 12 vibrates violently in the horizontal direction in the figure as if it were a single body.

The resonant frequency 10 of the resonator composed of the space 11 and the drive tube 12 is determined by equation (1).

Here, C is the sound velocity of the fluid, π is pi, and α is the correction coefficient.

When the columnar fluid 19 moves to the right, the fluid near the inlet of the drive tube 12 is driven to the right. During the process in which the columnar fluid 19 moves to the left, the fluid that has been stationary outside near the inlet is sucked into the pipe by the negative pressure generated, as shown by the curve in the figure, and then when the columnar fluid 19 moves to the right again. Driven to the right. As a result, a flow as shown by the arrow in the figure is formed within a few cycles after the start of operation. Although the flow is turbulent near the inlet of the drive pipe 12, slightly downstream, as shown by the straight line in the figure, a flow with a substantially constant flow velocity with little pulsation is formed. Therefore, using a reciprocating diaphragm as the drive source, a smooth flow can be obtained without the need for a smoothing device, and since it does not have large rotational inertia like a rotary drive source such as an electric motor, responsive flow control can be achieved. It can be carried out.

Problems to be Solved by the Invention However, the driving principle of the fluid in this device is based on the Helmholtz resonance phenomenon, but the resonant frequency of the Helmholtz resonance phenomenon tends to change due to changes in the temperature of the fluid, etc. If the frequency of 17 remains constant, it will deviate from the resonance phenomenon and the fluid driving efficiency will decrease. Further, reciprocating drive sources generally have lower work efficiency than rotary drive sources.

Therefore, this conventional fluid drive device has the disadvantage that the work efficiency decreases due to changes in fluid temperature, etc., and it is necessary to keep the work efficiency at its maximum by always matching the driving frequency of the diaphragm to the resonance frequency. be.

Means for Solving the Problems In order to solve the above problems, the present invention detects the vibration state of the fluid by installing a pressure sensor in the casing or drive pipe that forms the space, and uses the signal to drive the diaphragm. The drive power source is equipped with a control device that controls the frequency.

Operation: By using this technical means, the frequency of the drive power source is controlled by the control device so that the vibration state inside the space formed by the housing or the drive tube is maximized based on the signal from the pressure sensor attached to the housing or the drive tube. If controlled, the Helmholtz resonance phenomenon will be maintained at maximum conditions, and work efficiency will also be maintained at its maximum.

Embodiment FIG. 1 is a cross-sectional view showing an embodiment of the present invention.
A pressure sensor 21 is installed inside.

The pressure signal detected by the pressure sensor 21 is sent to the connection cable 23.
The information is transmitted to the control device 22 via. The control device 22 is electrically connected to the power supply device 2o.The other functions of the configuration 2 are the same as those of the conventional example shown in FIG. Next, this device will be explained. When this device is started, the columnar fluid 19 within the drive tube 12 undergoes a violent oscillating motion, as described in the conventional example. This means that intense pressure oscillations are occurring within the space 11 as well. The pressure sensor 21 detects this pressure vibration. Now, if the Helmholt resonant frequency of this device changes due to a change in the temperature of the fluid, etc., the frequency of the power supply device 2°, that is, the vibration frequency of the diaphragm 13, remains constant despite this. The resonance condition is broken and the pressure in the space 11 decreases. Therefore, since the output signal of the pressure sensor 21 decreases, this decrease in signal is used to control the control device 22 to control the stain source device 2o.
If the frequency of the diaphragm 12 is controlled so that the drop in the signal becomes zero or the level of the output signal of the pressure sensor 21 is maximized, the diaphragm 12 always matches the Helmpoltz resonance frequency. This means that the fluid is vibrating, and the fluid driving efficiency is maintained at its maximum.

Effects of the Invention The present invention provides a fluid drive that uses a reciprocating drive source, maintains a stable flow rate with little pulsation component, maintains flow characteristics with good controllability, and can always be used at maximum work efficiency. The device can be provided at low cost.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing a fluid drive device according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view showing a conventional example.・Space, 12・
... Drive tube, 13 ... Vibration plate, 20 ...
...Power supply device, 21...Pressure sensor, 22
...Control device, 23...Connection cable.

Claims (1)

[Claims] A casing, a drive tube connected to the casing, and a diaphragm provided on the casing form a Helmholtz resonance condition, a pressure sensor is provided in the casing or the drive tube, and the output of the pressure sensor A fluid drive device including a control device that controls a frequency of a power supply device that vibrates the diaphragm.