JP4475731B2 - Diaphragm pump - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a diaphragm pump that sends out a handling fluid by a reciprocating motion of a diaphragm, and more particularly to a structure of a peripheral ring interposed between two sheets constituting the diaphragm.
[0002]
[Prior art]
The diaphragm pump is a pump that reciprocates a membrane-like diaphragm and sends out a handling fluid. In many cases, the diaphragm has a circular shape, and its peripheral edge is fixed and reciprocates near the center. Therefore, since the periphery of the diaphragm is repeatedly bent by reciprocation, sufficient consideration is required for the shape of this portion.
[0003]
The diaphragm may be formed by bringing two sheets into close contact with each other. A peripheral ring interposed between the two sheets is provided on the peripheral edge of the diaphragm. The peripheral ring is provided with a through hole in the radial direction. This through-hole is normally closed by two sheets of diaphragms. However, if either or both of the sheets are torn, high pressure fluid will flow. If a pressure sensor is coupled to the through hole directly or via a pipe, the breakage of the sheet can be detected.
[0004]
[Problems to be solved by the invention]
As described above, when a peripheral ring is provided at the peripheral portion of the diaphragm composed of two sheets so as to be interposed between the sheets, the vicinity of the inner edge of the peripheral ring is repeatedly bent along with the reciprocating motion of the diaphragm. It becomes a part to receive.
[0005]
An object of the present invention is to prevent a portion subjected to repeated bending from being damaged.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the peripheral ring of the diaphragm pump of the present invention is gradually thinned inward in the vicinity of the inner edge, and a thin plate-like portion is formed at the tip portion. The going part has a concave shape. The thin plate-like portion of the tip portion has a thickness equal to or less than the thickness of one sheet constituting the diaphragm.
[0007]
Further, in the other peripheral ring of the present invention, the vicinity of the inner edge gradually becomes thinner in a tapered shape toward the inside.
[0008]
In the peripheral ring of the present invention, the radius of the tip of the inner edge is not more than half of the thickness of one sheet constituting the diaphragm.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention (hereinafter referred to as embodiments) will be described with reference to the drawings. FIG. 1 shows a schematic configuration of the diaphragm pump of the present embodiment. The piston 10 reciprocates in the cylinder 12 by a drive mechanism (not shown). A cylinder head 16 having a communication hole 14 is provided at the end of the cylinder 12 opposite to the end where the piston 10 is inserted. Further, a diaphragm head 18 is disposed on the right side of the cylinder head 16 in the figure, and a cavity 20 similar to the shape of an abacus ball is formed by a recess provided on the opposing surfaces of the cylinder head 16 and the diaphragm head 18. . The cavity 20 is divided into two chambers by a diaphragm 22. That is, the chamber is divided into a fluid pressure chamber 24 connected to the cylinder chamber via the communication hole 14 and a diaphragm chamber 30 communicating with the suction pipe 26 and the discharge pipe 28 for the handling liquid.
[0010]
The cylinder 12, the communication hole 14, and the fluid pressure chamber 24 are filled with a working fluid. When the piston 10 is reciprocated, the diaphragm 22 is also reciprocated accordingly, and the volume of the diaphragm chamber 30 is changed. The suction pipe 26 and the discharge pipe 28 are provided with check valves 32 and 34, respectively, and the handling liquid flows in one direction from the suction pipe 26 to the discharge pipe 28 by the action of the check valve. .
[0011]
2 and 3 show details of the structure near the end of the diaphragm 22. The diaphragm 22 is formed from two sheets 36 and 38. An annular peripheral ring 40 is disposed on the peripheral edge of the diaphragm 22 and is interposed between the two sheets 36 and 38. As shown in FIGS. 2, 3 and 4, the peripheral ring 40 has a thin annular plate shape. Through holes 42 and 44 are provided at two locations in the radial direction of the ring (upper and lower in FIG. 4). The lower through-hole 44 is normally sealed with a plug 46. The upper through hole 42 communicates with a fluid pressure gauge (not shown) via a pipe 48 and a check valve 50. Before operation, the two sheets 36 and 38 of the diaphragm are in a state with a slight gap as shown in FIG. When the operation of the pump is started, the pressure in the cavity 20 increases, the pressure between the two sheets 36 and 38 is clogged by the pressure, and the state is as shown in FIG. The liquid is filled between the sheets 36 and 38 before operation, but when the sheets are in close contact with each other, the sheet 36 and 38 are discharged from the plug 51 through the through hole 42, the pipe 48 and the check valve 50. The The fluid once discharged by the check valve 50 does not flow backward. After the sheets 36 and 38 are in close contact, the plug 51 is tightened.
[0012]
When the pump is operating normally, the two sheets 36 and 38 of the diaphragm are in close contact with each other, so that the pressure in the cavity 20 does not reach the check valve 50 and the fluid pressure gauge. If one or both of the two sheets 36 and 38 of the diaphragm are damaged, the pressure in the fluid pressure chamber 24 or the diaphragm chamber 30 reaches the check valve 50 through the through hole 42 and the pipe 48 and pushes this valve. open. In addition, this pressure reaches the fluid pressure gauge, which detects the breakage of the diaphragm 22.
[0013]
When the two sheets 36 and 38 of the diaphragm are in close contact with each other, for example, as shown in FIG. Thus, the sheet 38 is greatly bent. This portion is weak, and is easily damaged when subjected to repeated bending by the reciprocating motion of the diaphragm 22. If the tip of the inner edge draws a relatively large arc and is round like the peripheral ring 140 shown in FIG. 5, the diaphragm 22 is biased from the center as described above, and a weak portion is likely to occur.
[0014]
In the present embodiment, as shown in FIGS. 2 and 3, the vicinity of the inner edge of the peripheral ring 40 is gradually thinner toward the center of the ring. In addition, a concave surface is formed instead of a single curved surface, and the tip is formed thinner. The thickness of the tip portion of the peripheral ring 40 of this embodiment is about half of the sheets 36 and 38, and the radius of the tip arc is about 1/4 of the sheet. In the case of this shape, it is possible to adopt the device that used the peripheral ring 140 shown in FIG. 5 without changing the shapes of the cylinder head 16 and the diaphragm head 18. With the above configuration, the center of thickness of the peripheral ring 40 and the diaphragm 22 is prevented from shifting when the two sheets 36 and 38 of the diaphragm are brought into close contact with each other in the initial operation. If the strength of the tip of the inner edge of the peripheral ring is sufficiently high, the thickness of the tip can be made the same as that of the sheets 36 and 38, and the radius of the tip arc can be increased to about half the sheet thickness. Center misalignment can be prevented.
[0015]
FIG. 6 shows another example of the tip shape of the peripheral ring. The peripheral ring 54 is tapered near the tip of the inner edge, and unlike the peripheral ring 40 shown in FIGS. 2 and 3, no concave surface is formed. In this case, it is necessary to change the surrounding shape in accordance with the shape of the peripheral ring 40. Therefore, when this peripheral ring 54 is used, a cylinder head 56 and a diaphragm head 58 having a shape that forms a gap substantially equal to the thickness of one of the sheets 36 and 38 with respect to the tapered portion are employed.
[0016]
As described above, by thinning or sharpening (tapering) the tip on the inner edge side of the peripheral ring, the thickness center of the peripheral ring is shifted from the center of the diaphragm when the two sheets are in close contact with each other. Is prevented, and the durability of the diaphragm is improved.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic configuration of a diaphragm pump.
FIG. 2 is a cross-sectional view showing a detailed shape of a peripheral ring of the present embodiment, and particularly shows a state before two sheets forming a diaphragm are brought into close contact with each other.
FIG. 3 is a cross-sectional view showing a detailed shape of a peripheral ring of the present embodiment, and particularly shows a state after two sheets are brought into close contact with each other.
FIG. 4 is a diagram showing a schematic shape of a peripheral ring.
FIG. 5 is a view showing a state where the sheet is largely bent at the front end of the peripheral ring.
FIG. 6 is a diagram showing another example of the shape of the peripheral ring.
[Explanation of symbols]
10 pistons, 16, 56 cylinder heads, 18, 58 diaphragm heads, 20 cavities, 22 diaphragms, 30 diaphragm chambers, 36, 38 seats, 40, 54 peripheral rings, 52 concave surfaces.

Claims (3)

A diaphragm pump for delivering a handling fluid by a reciprocating motion of a diaphragm;
Two sheets that are in close contact with each other to form the diaphragm;
A ring-shaped peripheral ring provided on the peripheral edge of the diaphragm and interposed between the two sheets;
Have
The inner edge of the peripheral ring is gradually thinned inward, a thin plate-like part is formed at the tip part, and a concave surface is formed in this gradually thinning part,
The thin plate-like portion has a thickness equal to or less than the thickness of one of the sheets constituting the diaphragm.
Diaphragm pump. The diaphragm pump according to claim 1,
The front end radius of the inner edge of the peripheral ring is a diaphragm pump that is less than half the thickness of one sheet. A diaphragm pump for delivering a handling fluid by a reciprocating motion of a diaphragm;
Two sheets that are in close contact with each other to form the diaphragm;
A ring-shaped peripheral ring provided on the peripheral edge of the diaphragm and interposed between the two sheets;
Have
The inner edge of the peripheral ring is gradually thinned inward, and a thin plate-like portion having a thickness equal to or less than one thickness of the sheet constituting the diaphragm is formed at the tip portion.
The front end radius of the inner edge of the peripheral ring is a diaphragm pump that is less than half the thickness of one sheet.

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