JPS5841364Y2 - pressure generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pressure generator that generates pressure that changes at a constant frequency.

As a conventional device of this type, there is one in which a motor rotates a cam installed in a conduit through which fluid pressure is guided, thereby obtaining pressure that changes at a constant frequency.

The disadvantages of this conventional device are that it has a complicated configuration and that it requires not only fluid (pressure) but also electric power as a driving source.

Use in atmospheres where flammable gases are present was almost impossible due to the latter drawback.

An object of the present invention is to realize a pressure generating device with a simple configuration that does not require electric power or the like and can be driven only by fluid.

In the present invention, fluid is injected toward a vibrating plate, and its back pressure is obtained as an output signal.

The present invention will be explained in detail below with reference to the drawings.

FIG. 1 is a configuration diagram showing an embodiment of a pressure generating device according to the present invention, and FIGS. 2 to 4 are operation explanatory diagrams showing a section XX' of FIG. 1.

In the figure, 1 is a belt-shaped vibrating plate with a rectangular cross section, and 2 has a rectangular slit-shaped opening that jets fluid toward the plate 1 parallel to the plane containing the plate 1. 3 and 4 are plate 1
a column fixed at both ends so as to create a constant tension on the column, 5
is a base for fixing the pillars 3 and 4, 6 is a pipe that guides the back pressure of the nozzle 2, and 7 is a booster that amplifies and outputs the pressure guided by this vibro.

This booster is fixed to the base 5. The operation of the pressure generating device configured in this way will be explained.

When fluid is ejected from the nozzle 2 toward the plate 1 as shown in FIG. 2, the plate 1 in the fluid starts to vibrate due to the action of vortices and the like generated around it.

The amplitude of this vibration gradually increases and thereafter remains at a constant value.

That is, the plate 1 is placed in the position shown in FIG.
It will vibrate alternately back and forth between the positions shown in the figure.

The force that the plate 1 receives will be explained with reference to the positions shown in FIGS. 3 and 4.

In these positions, the inside of plate 1 (jet side)
Because the fluid present at plate 1 is drawn into the jet flow, plate 1
A pressure difference is created on both sides of the plate 1, and a force p is generated that pushes the plate 1 inward.

Therefore, plate 1 (considered to be a beam fixed at both ends)
In addition to the restoring force of the spring, the above-mentioned force p is applied inward (in the direction of the arrow).

Therefore, the plate 1 is strongly pushed by these combined forces and plunges into the fluid again, and with the help of inertial force, it reaches the opposite side of the jet and is now subjected to a force in the opposite direction.

Therefore, the same operation as above is repeated, and the vibration of the plate 1 continues.

Here, the vibration frequency f of the plate 1 is expressed by: k: constant determined by vibration mode t effective length of nibrate 1 T tension applied to nibrate 1 S cross-sectional area of nibrate 1 d density of nibrate 1 (This formula was obtained on the premise that t is sufficiently larger than S).

On the other hand, regarding the back pressure of the nozzle 2, the state shown in Fig. 2 is the highest because the area near the injection port is blocked by the jet to the greatest extent, and the back pressure in the nozzle 2 is the highest in the state shown in Figs. 3 and 4. It will be the lowest because there will be no obstacles.

Therefore, the back pressure of the nozzle 2 changes at a constant frequency, and the booster 7 amplifies and outputs the pressure that changes at the frequency fb expressed by the following equation.

In this equation, since t, T, s and d are constant, the frequency fb is constant.

Therefore, from the output end of the booster T, a constant frequency f
It is possible to obtain a pressure signal that changes at b.

Here, the frequency fb can be adjusted by changing the effective length, tension, etc. of the plate.

In addition, in the above description, the plate 1 is shown and described with both ends fixed, but the same is true even if one end is fixed.

In addition, in the device shown in Fig. 1 of the present invention, when the slit width of the jet nozzle and the thickness of the plate 1 are selected to be approximately equal, experimentally, the most stable air pressure signal with a good characteristic of changing at a constant frequency is obtained. I was able to do that.

As described above, according to the present invention, a pressure generating device that operates only with fluid can be realized with a simple configuration.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the pressure generating device according to the present invention, and FIGS. 2 to 4 are operation explanatory diagrams showing the XX cross section of FIG. 1. 1...Plate, 2...Ejection nozzle, 3, 4...
Pillar, 5...Base, 6...Pipe, 7...Booster.

Claims (1)

[Scope of utility model registration request] a vibrating plate having at least one end fixed; a fluid ejecting means for ejecting a fluid toward the plate parallel to a plane including the plate; and a back pressure of the fluid ejecting means being guided to the plate. A pressure generating device comprising a converting section that generates a pressure that changes at a frequency corresponding to the frequency of vibration.