JP2002257050A - Diaphragm pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To early detect the penetration of handling liquid into a fluid pressure chamber in a diaphragm pump. SOLUTION: Hydrogen concentration in a diaphragm chamber 28 for receiving or discharging the handling liquid and an adjacent chamber (fluid pressure chamber 22) through a diaphragm 20 is set different from that of the handling liquid. A pH sensor 34 for detecting the hydrogen concentration is provided. Variation of the hydrogen ion concentration due to the penetration of the handling liquid is monitored by the pH sensor 34.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diaphragm pump for delivering a handling fluid by reciprocating a diaphragm.

[0002]

2. Description of the Related Art A diaphragm pump is a pump which reciprocates a membrane diaphragm and sends out a handling liquid.
The diaphragm is driven by, for example, transmitting reciprocating motion of a piston to the diaphragm via a fluid. Fluid flows into and out of a fluid pressure chamber provided on one surface of the diaphragm by the reciprocating motion of the piston, and drives the diaphragm.
On the surface of the diaphragm opposite to the fluid pressure chamber, a diaphragm chamber into and out of which the handling liquid flows is formed.

[0003]

In the above-described diaphragm pump, when the diaphragm is damaged or the handling liquid having a high permeability is used, the liquid permeates the diaphragm and the handling liquid becomes a fluid pressure chamber. In some cases. If the handling liquid is a corrosive fluid, parts in the fluid pressure chamber are corroded, causing problems such as damage to the pump body.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and has as its object to detect early the intrusion of the handling liquid into the fluid pressure chamber and prevent the pump from being damaged.

[0005]

In order to solve the above-mentioned problems, a diaphragm pump according to the present invention makes the hydrogen ion concentration in a fluid pressure chamber different from that of a handling liquid, and detects a change in the hydrogen ion concentration. Detects intrusion of handling liquid.

For the detection of the hydrogen ion concentration, for example, a substance whose color changes according to the hydrogen ion concentration is mixed in the fluid in the fluid pressure chamber, and this color change is observed through a viewing window. It is also possible to detect and monitor the hydrogen ion concentration of the fluid in the fluid pressure chamber by using a sensor for measuring the hydrogen ion concentration.

[0007]

Embodiments of the present invention (hereinafter referred to as embodiments) will be described below with reference to the drawings. FIG. 1 shows a schematic configuration of a diaphragm pump according to the present embodiment. The piston 10 reciprocates in the cylinder 12 by a drive mechanism (not shown). Of the cylinder 12,
A cylinder head 14 is formed at the end opposite to the end where the piston 10 is inserted. Further, a diaphragm head 16 is disposed on the right side of the cylinder head 14 in the drawing, and a cavity 18 is formed by a recess provided on a surface of the cylinder head 14 facing the diaphragm head 16. The cavity 18 is divided into two chambers by a diaphragm 20. That is, the fluid pressure chamber 22 connected to the cylinder chamber in which the piston reciprocates, and the suction pipe 24
And a diaphragm chamber 28 communicating with the discharge pipe 26.

[0008] A fluid pressure chamber 22 in the cylinder 12 is filled with a working fluid. When the piston 10 reciprocates, the diaphragm 20 reciprocates accordingly, and the volume of the diaphragm chamber 28 changes. Suction pipe 24 and discharge pipe 2
6 are provided with check valves 30 and 32, respectively.
By the action of the check valve, the handling liquid flows in one direction from the suction pipe 24 to the discharge pipe 26.

When handling a highly corrosive handling liquid, if the handling liquid enters the fluid pressure chamber 22, the components inside the chamber are corroded and the pump function is lost. Therefore, it is necessary to detect the intrusion of the handling liquid before the corrosion of the components in the fluid pressure chamber starts, and to take an early action.

An example of a highly corrosive handling liquid is hydrofluoric acid, which permeates a fluororesin diaphragm. Although some materials are difficult to permeate hydrofluoric acid, such materials generally have poor flexibility, and thus are difficult to use in the diaphragm.
There is a problem that the discharge amount per reciprocation cannot be increased and the apparatus becomes large.

In the diaphragm pump shown in FIG. 1, a pH sensor 34 for detecting the hydrogen ion concentration of the fluid in the fluid pressure chamber 22 is provided to monitor the hydrogen ion concentration. It is known that corrosion of general steel is strongly promoted when the hydrogen ion concentration (pH) is 4 or less, and when the pH value in the fluid pressure chamber 22 reaches this value or a predetermined value close to this value. When the value becomes the value, the notification device 36 notifies the monitoring person.

FIG. 2 is a schematic view of a diaphragm pump showing another embodiment. In the diaphragm pump shown in this figure, the same components as those of the diaphragm pump shown in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

The characteristic feature of the diaphragm pump shown in FIG. 2 is the configuration of the diaphragm. The cavity 18 between the cylinder head 14 and the diaphragm head 16 is provided with an insert chamber 38 sandwiched between the heads 14 and 16, and two diaphragms 40 and 42 disposed on both sides of the insert chamber 38. The insert chamber 38 has concave sides on the left and right sides in the figure, and further has a plurality of communication holes communicating left and right. Piston 10
Drives the diaphragm 40, the other diaphragm 42 is driven via the fluid in the intermediate chamber 44 between the two diaphragms 40 and 42, whereby the handling fluid is discharged. In the insert chamber 38,
A monitoring plug 48 provided with a monitoring window 46 is inserted.

An intermediate chamber 44 between the two diaphragms 40 and 42 is filled with a fluid containing a reagent whose color changes depending on the hydrogen ion concentration. By monitoring the change in the color of the fluid in the intermediate chamber, intrusion of the handled fluid into the intermediate chamber 44 is detected. As the pH reagent, pH 3
In (5), a Congo red liquid that changes color from blue-violet to red and red can be used. Also, as mentioned above,
It is preferable to monitor so that it does not become less than 4.
It is also preferable to use methyl red which changes color from blue to yellow at a pH of 4.2 to 6.

Further, instead of the monitoring plug 48, the same one as the pH sensor 34 and the notification device 36 used in the diaphragm pump of FIG. 1 can be used.

Further, even if the handling fluid does not pass through the diaphragm, the handling fluid may enter the fluid pressure chamber 22 due to damage to the diaphragm. According to the diaphragm pump of each of the above-described embodiments, in such a case, it is possible to early detect breakage of the diaphragm.

As described above, the intrusion of the handled fluid into the fluid pressure chamber can be detected at an early stage before a specific failure occurs. Thereby, the interval of the periodic inspection for performing the disassembly and maintenance can be lengthened, and the equipment efficiency improves.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a diaphragm pump of the present embodiment.

FIG. 2 is a diagram illustrating a schematic configuration of a diaphragm pump according to another embodiment.

[Explanation of symbols]

10 pistons, 12 cylinders, 20, 40, 42
Diaphragm, 22 fluid pressure chambers, 28 diaphragm chambers,
34 pH sensor, 44 Intermediate chamber.

Claims (4)

[Claims] 1. A diaphragm pump for delivering a handling liquid by reciprocating a diaphragm, wherein the handling liquid is an adjacent chamber which is separated from the diaphragm chamber through which the handling liquid flows in and out, and which is different from the handling liquid. A diaphragm pump comprising: an adjacent chamber in which a pH detection solution having a hydrogen ion concentration is stored; and pH monitoring means for monitoring a change in the hydrogen ion concentration of the pH detection solution. 2. The diaphragm pump according to claim 1, wherein the pH monitoring means includes a hydrogen ion concentration reagent dissolved in the pH detection liquid, and a monitoring window for viewing a change in color of the hydrogen ion concentration reagent. And a diaphragm pump. 3. The diaphragm pump according to claim 1, wherein said pH monitoring means is a pH detecting device for detecting a hydrogen ion concentration of a pH detecting liquid. 4. The diaphragm pump according to claim 1, wherein the adjacent chamber is a hydraulic chamber filled with a liquid that transmits a reciprocating motion of a piston to the diaphragm. A diaphragm pump that drives a diaphragm.