JPH01283497A - Pressure pulsation suppression device in fluid pipe line - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for suppressing pressure pulsations occurring in any fluid piping system that involves fluid transport, including the piping system of a paper machine.

[Prior Art] For example, when the stock is discharged from the head box of a paper machine, if there is pulsation in the pressure of supplying the stock to the head box, the thickness of the paper will be adversely affected.

As a conventional pulsation damping means, an accumulator a as shown in FIGS. 7 and 8 is generally employed. That is, an accumulator a whose interior is partitioned into a gas chamber C and a liquid chamber d by a rubber membrane is installed in the middle of a conduit C, and a liquid chamber d communicating with the conduit e is connected to a gas chamber C and a liquid chamber d. The pulsations of the fluid are guided and the compressibility of the gas sealed in the gas chamber C absorbs the pulsations of the fluid. In the figure, r is an orifice.

[Problems to be Solved by the Invention] However, in the conventional method, since the accumulator a has a fixed characteristic, it is difficult to attenuate pulsation over a wide frequency range.

Further, since the conventional accumulator a is a passive type, there is a limit to the amount of pulsation attenuation, and the device becomes larger.

The object of the present invention is to provide a compact pressure pulsation suppressing device capable of actively suppressing pulsations of various frequencies.

[Means for Solving the Problems] The present invention provides a pressure sensor that includes a movable wall provided on at least a portion of the pipe wall of a fluid conduit, an actuator connected to the movable wall, and that detects fluid pressure within the fluid conduit. is attached near a movable wall, and the pressure detected by the pressure sensor is fed back to drive the actuator.

[Function] Pressure pulsations occurring in the fluid pipeline are detected by the pressure sensor, and the actuator vibrates the movable wall in the direction in which the pressure pulsations are absorbed, reducing the pressure pulsations in the pipeline. .

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention, in which a part of the pipe wall 2 in the middle of the pipe line 1 is cut out, and a rubber membrane 9 is inserted into the cutout part 3.
A flexible membrane 4 is stretched, and a diaphragm 5 is placed approximately in the center of the flexible membrane 4.
is hardened, and the tip of a vibrating shaft 7 of an electric vibrator 6 is connected to the vibrating plate 5.

A pressure sensor 8 for detecting the pressure of the fluid in the pipe line 1 is provided near the movable part of the pipe line 1, a pressure signal detected by the pressure sensor 8 is amplified by a sensor amplifier 9, and the amplified signal is passed through a bypass filter. 10 to extract only the pressure fluctuations. After passing the fluctuation signal through a compensation filter 11 for improving the stability of the control system and improving the pulsation suppression effect,
The signal is input to the drive amplifier 12 to drive the vibrator 6.

In the following, when the pressure pulsations in the pipe line 2 are on the upper η1 side, the flexible membrane 4 moves downward in FIG. 1, absorbs the pulsations, and has a signal polarity of fIj.

As described above, when the pressure pulsation suppressing device of the present invention is not activated, the pressure pulsation that occurs in the pipe line 1 as a disturbance as shown in FIG. It becomes.

When the pressure pulsation suppressing device of the present invention is activated, the pressure pulsation occurring in the pipe line 1 is detected by the pressure sensor 8, is amplified by the sensor amplifier 9, and is suppressed by the bypass filter 1.
0, only the pressure fluctuation is taken out, further stabilized by the compensation filter II, and then manually inputted to the drive amplifier 12. 8 is driven to have a phase opposite to that of the detected pressure pulsation.

As a result, the foot bank control of the pressure pulsation suppressing device is performed to suppress pressure pulsations due to disturbances in the pipe line 1, and the pressure pulsations in the pipe line 1 are reduced.

That is, in FIG. 2, for simplicity, the transfer function of the pressure pulsation suppressor 15 is assumed to be a proportional residue (constant K), and the phase of the pressure pulsation suppressor output (n canceling pulsation) When the feedback loop is closed in such a way that the pressure pulsation is reversed (1'L phase), negative feedback is performed, and as shown in FIG. 3, the influence of disturbance is suppressed and the pulsation of the pressure inside the tube is reduced.

In the case of Fig. 3, the canceling pulsation X is obtained by amplifying the pressure pulsation y in the pipe, so it is impossible to make the pressure pulsation in the pipe 1 completely zero unless the constant Can not. That is, in Figure 3, if ε is set to ε-x-yy-, a part is required to make 1+K E-0. The characteristics of the sensor 8 have complex dynamic characteristics, and the entire pulsation suppressing device is not a simple proportional element. Therefore, if the gain of the suppression device is increased in an attempt to enhance the suppression effect, the feedback system becomes unstable, so the compensation filter I) can suppress such instability.

4 and 5 show other embodiments of the present invention, in which the pipe line 1
This is an example of a case where the diameter is large. In a configuration substantially similar to that of the embodiment described above, a rectifier plate 1 is provided on the inner wall 13V1 of the large-diameter pipe line 1.
4 is installed perpendicularly to the flexible membrane 4, and the current plate 14
This is an example in which the pressure sensor 8 is provided approximately at the center of the .

In the case of this embodiment, even when the flexible membrane 4 vibrates, the conduit 2
The flow of fluid inside the pipe is not disturbed, and the distance between the movable part and the pressure sensor 8 is shortened, so the time it takes for the pressure generated in the movable part to reach the pressure sensor 8 is shortened. The control system may become unstable due to a delay in pressure propagation due to an increase in diameter, etc., which will be resolved. Since the purpose of this embodiment is to shorten the distance between the movable part and the pressure sensor, the current plate 14 may be mounted horizontally on the flexible membrane 4, and the pressure sensor 8 may also be mounted horizontally. Good too.

FIG. 6 shows still another embodiment of the present invention, in which a pressure sensor 8 is provided through a flexible membrane 4 on a diaphragm 5 in substantially the same configuration as the previous embodiment.

In the case of this embodiment, the time required for the pressure generated in the movable part to reach the pressure sensor 8 in the large-diameter pipe l is the shortest, making it possible to detect pressure without time delay and suppress pressure pulsation. The device improves the stability of the control system.

It should be noted that the present invention is not limited to only two embodiments, and may be modified in various ways without departing from the gist of the present invention, such as being able to include multiple pairs of movable walls and actuators. Of course.

[Effects of the Invention] As explained above, the pressure pulsation suppressing device for a fluid pipeline system of the present invention exhibits various excellent effects as described below.

(I) Since the movable wall is actuated by an actuator, it is possible to actively attenuate large pulsations, resulting in a large pressure pulsation suppressing effect.

(It) The pressure pulsation suppression effect is greater than that of the conventional passive type, so the device can be made more compact. Therefore, there are fewer restrictions on installation location, and it can be installed in the most effective location.

■ Feedback 1. Since it is a control method, it is not easily affected by changes in the characteristics of the pipeline system, and a stable pressure pulsation suppressing effect can be expected at all times.

■ Since it is a method that directly feeds back pressure, any pressure pulsation can be attenuated regardless of the cause of the pressure pulsation.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of one embodiment of the device l'\ of the present invention;
1 is a diagram showing the device shown in FIG. 1 in an inoperative state, FIG. 3 is a diagram showing the device shown in FIG. 1 in an operating state, and FIG. 4 is an explanation of another embodiment of the device of the present invention. Figure 5 is the ■ of Figure 4.
-■ direction arrow view, FIG. 6 is an explanatory diagram of still another embodiment of the device of the present invention, FIG. 7 is a diagram showing an example of a conventional accumulator, and FIG. 8 is a diagram of the accumulator shown in FIG. 7. It is an internal detailed diagram. 1 is a pipe, 4 is a flexible membrane, 5 is a diaphragm, 6 is a vibrator, 8
indicates a pressure sensor, and 12 indicates a drive amplifier.

Claims (1)

[Claims] 1) Providing a movable wall on at least a part of the pipe wall of the fluid pipe,
An actuator is connected to the movable wall, a pressure sensor for detecting fluid pressure in the fluid pipeline is attached near the movable wall, and the detected pressure of the pressure sensor is fed back to drive the actuator. A pressure pulsation suppressor for fluid piping systems.