JPH08219363A - Pulsation absorber - Google Patents

Abstract

PURPOSE: To heighten pulsation absorbing effect by always obtaining diaphragm reaction corresponding to fed liquid pressure in order to absorb pulsation in a diaphragm type pulsation absorber making use of air pressure. CONSTITUTION: A pulsation absorber is additionally provided with the automatic follow-up change function of air pressure according to the change of fed liquid pressure, that is, a diaphragm 28 for partitioning a liquid chamber 24 and an air chamber 26 in a device body 12 is in a neutral position when there is no difference between the fed liquid pressure and the air pressure while moving toward the low pressure side when there is difference. Feedback control is therefore performed to control air pressure supplied into the air chamber 24 according to the displacement quantity from the neutral position of the diaphragm 28 so 09 to bring the diaphragm close to the neutral position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diaphragm type pulsation absorbing device utilizing air pressure.

[0002]

2. Description of the Related Art When a plunger pump or the like is used, the pulsation of the liquid feed flow rate inevitably occurs in the liquid feed conduit from the pump. Further, even if a pulsation-free pump using a special cam is used, pulsation cannot be completely eliminated. Therefore, a pulsation absorbing device for absorbing the pulsation of the liquid supply flow rate is often provided in the liquid supply conduit from the pump.

As the above-described pulsation absorbing device, a diaphragm type device has been widely used conventionally.

In this diaphragm type pulsation absorbing device, as a method of applying a diaphragm reaction force for balancing the diaphragm against the liquid sending pressure, for example, Japanese Utility Model Laid-Open No. 4-82490 and Japanese Utility Model Laid-Open No. 61-16488.
There is known one using a spring force or one using air pressure as disclosed in Japanese Patent Laid-Open No. 9.

In any of these pulsation absorbers,
The magnitude of the spring force or the air pressure is set so that the diaphragm reaction force corresponding to the liquid feeding pressure is obtained by assuming the magnitude of the liquid feeding pressure in advance. This is because in the diaphragm-type pulsation absorbing device, the pulsation absorbing effect is highest when the liquid feeding pressure on both sides of the diaphragm and the diaphragm reaction force are the same, and the pulsation absorbing effect decreases as the difference increases. is there.

[0006]

However, even if the spring force or the air pressure is set to such a magnitude that the diaphragm reaction force corresponding to the liquid sending pressure is obtained as described above, the liquid sending pressure is assumed in advance after the setting. If the value changes from the above value, the pulsation absorbing effect will be reduced if the diaphragm reaction force remains unchanged.

On the other hand, in the pulsation absorbing device using the spring force, it is structurally difficult to change the once set diaphragm reaction force.

On the other hand, in the pulsation absorbing device using the air pressure, it is possible to change the set diaphragm reaction force by changing and adjusting the air pressure in the air chamber partitioned by the liquid chamber and the diaphragm. However, for that purpose, there is a problem in that it is necessary to change and adjust the air pressure each time the liquid delivery pressure changes.

The present invention has been made in view of such circumstances, and the pulsation absorbing effect can be enhanced by constantly obtaining the diaphragm reaction force corresponding to the liquid feeding pressure for pulsation absorption. It is intended to provide a pulsation absorbing device.

[0010]

SUMMARY OF THE INVENTION The present invention employs a diaphragm type pulsation absorbing device that utilizes air pressure so that the set diaphragm reaction force can be changed. By adding a function for automatically following and changing the above, the above object is achieved.

That is, as described in claim 1, a liquid chamber having an inlet / outlet for liquid circulation in the casing,
In a pulsation absorbing device provided with an air chamber having a pressure supply port and a diaphragm separating the liquid chamber and the air chamber, an air pressure supply means for supplying an air pressure to the air chamber via the pressure supply port. , A displacement amount detecting means for detecting a displacement amount from the neutral position of the diaphragm, and controlling the supply air pressure into the air chamber according to a detection value of the displacement amount detecting means so as to bring the diaphragm close to the neutral position. And a supply air pressure control means for controlling the supply air pressure.

The "neutral position" means the diaphragm position in the state where there is no difference between the liquid feeding pressure and the air pressure.

In the pulsation absorbing device, the position of the diaphragm separating the liquid chamber and the air chamber is in the neutral position if there is no difference between the liquid feeding pressure and the air pressure, and if there is a difference, it moves to the lower pressure side. However, in the present invention, feedback control for controlling the supply air pressure into the air chamber according to the displacement amount from the neutral position of the diaphragm to bring the diaphragm closer to the neutral position is performed. It is possible to always obtain a diaphragm reaction force that is commensurate with the pressure of the liquid to be absorbed. And this
Unlike the conventional case, a high pulsation absorbing effect can be constantly obtained without the need to change and adjust the air pressure every time the liquid feeding pressure changes, and the present invention will be described below with reference to the drawings.

FIG. 1 is an overall configuration diagram showing a pulsation absorbing device according to the present invention.

The pulsation absorbing device 10 includes a device body 12
, Displacement sensor 14, displacement meter amplifier 16, controller 1
8, an electropneumatic converter 20, and an air pressure supply means (not shown).

The apparatus body 12 has a liquid chamber 2 having an inlet 24a and an outlet 24b for liquid circulation in a casing 22 composed of a pair of casing halves 22A and 22B.
4, an air chamber 26 having a pressure supply port 26a, and a rubber diaphragm 28 for partitioning the liquid chamber 24 and the air chamber 26.

The apparatus main body 12 is provided in the middle of a liquid feed conduit from a liquid feed pump (not shown), and a liquid outlet from the liquid feed pump is introduced into the liquid chamber 24 through an inlet 24a. When the liquid delivery pressure changes in the liquid chamber 24, the diaphragm 28 is displaced and the pulsation in the liquid delivery conduit is suppressed.

Air pressure is supplied from the air pressure supply means into the air chamber 26 through the pressure supply port 26a.

The displacement sensor 14 is attached to the casing half 22B, and is located at the neutral position of the diaphragm 28 (the diaphragm position when the liquid feeding pressure in the liquid chamber 24 and the air pressure in the air chamber 26 are equal to each other). In the example, as shown in the figure, the displacement amount from the position where the diaphragm 28 is in a flat state) is detected.
The detection signal of the displacement sensor 14 is the displacement meter amplifier 1 described above.
After being amplified at 6, it is input to the controller 18.

The controller 18 controls the air pressure supplied to the air chamber 26 in accordance with the input signal value from the displacement meter amplifier 16 so that the diaphragm 28 approaches the neutral position. Specifically, the controller 18 is provided with respect to the electropneumatic converter 20 provided in the air pressure supply path,
An operation signal (4-2) corresponding to the input signal value (0-5V)
The input air pressure is controlled by inputting 0 mA).

Next, the operation of the present invention will be described.

The position of the diaphragm 28 that divides the liquid chamber 24 and the air chamber 26 in the apparatus main body 12 is in the neutral position if there is no difference between the liquid feeding pressure and the air pressure, and if there is a difference, the pressure is lower. In the present embodiment, feedback control is performed to control the supply air pressure into the air chamber 24 in accordance with the displacement amount of the diaphragm 28 from the neutral position to bring the diaphragm 28 closer to the neutral position. With this configuration, it is possible to constantly obtain a diaphragm reaction force that is commensurate with the liquid supply pressure for pulsation absorption. As a result, unlike the conventional case, a high pulsation absorption effect can always be obtained without the need to change and adjust the air pressure each time the liquid delivery pressure changes.

[0023]

EXAMPLE FIG. 2 is a graph showing the pulsation absorbing effect when the pulsation absorbing device 10 is provided in the liquid feed line of the plunger pump.

As is apparent from this graph, when the pump is rotating at a rotational speed of about 300 rpm, the conventional pulsating suction device, like the pulsating suction device of the present invention, has a pressure between the liquid feeding pressure and the air pressure. The pressure difference is maintained at zero or an extremely small value, and the flow pulsation rate is maintained at a low level. However, when the pump becomes lower rotation (200 rpm) or higher rotation (400 rpm), the liquid flow line When the conventional pulsation absorbing device is provided, the flow pulsation rate increases rapidly. At this time, the pressure difference between the liquid feeding pressure and the air pressure also rapidly increases.

On the other hand, as is clear from the graph,
In the case where the pulsation absorbing device 10 of the present invention is provided in the liquid supply conduit, the pressure difference between the liquid supply pressure and the air pressure is obtained even if the pump is rotated at low speed (200 rpm) or high speed (400 rpm). Is maintained at a very small value, and
The flow pulsation rate is kept low regardless of the pump speed.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing a pulsation absorbing device according to the present invention.

FIG. 2 is a graph showing the operation of the embodiment.

[Explanation of symbols]

 10 Pulsation Absorber 12 Device Main Body 14 Displacement Sensor 16 Displacement Amplifier 18 Controller 20 Electropneumatic Converter 22 Casing 22A, 22B Casing Half 24 Liquid Chamber 24a Inlet 24b Outlet 26 Air Chamber 26a Pressure Feed Port 28 Diaphragm

Claims (1)

[Claims] 1. A pulsation absorber in which a liquid chamber having a liquid flow inlet / outlet, an air chamber having a pressure supply port, and a diaphragm separating the liquid chamber and the air chamber are provided in a casing, Air pressure supply means for supplying air pressure into the air chamber through a pressure supply port, displacement amount detection means for detecting a displacement amount from the neutral position of the diaphragm, and the diaphragm so as to approach the neutral position, And a supply air pressure control means for controlling the supply air pressure into the air chamber according to the detection value of the displacement amount detection means.