JP2523493Y2 - Liquid plunger pump seal structure - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing structure of a liquid plunger pump used for a pressure booster requiring a high pressure.

[0002]

2. Description of the Related Art As shown in FIG. 3, a conventional liquid plunger pump has a plunger 102 slidably provided in a cylinder 101, a discharge valve 103 near the end of the cylinder 101, and a suction valve at the end of the cylinder 101. The suction valves 104 are connected to a tank 106 via a suction line 105. Here, the discharge valve 103 is configured such that the check valve 108 urged by the spring 107 is seated on the tapered valve seat 109 or separated from the tapered valve seat 109 so that the discharge hole 110 of the cylinder 101 is discharged.
Open and close. In addition, the suction valve 104 allows the check valve 112 urged by the spring 111 to be seated on the tapered valve seat 113 or separated from the tapered valve seat 113 so that the suction hole 11
4 Open and close.

Here, when the plunger 102 moves to the left, that is, the direction in which it comes out of the cylinder 101, the pressure in the cylinder 101 decreases due to the moved volume, and the external pressure of the suction valve 104 is reduced.
(Atmospheric pressure). This differential pressure is received in the direction in which the suction valve 104 opens, and when the received pressure becomes greater than the spring force of the spring 111, the check valve 112 is separated from the taper valve seat 113 and the suction valve 104 opens. When the liquid is sucked by the differential pressure and the differential pressure disappears, the check valve 112 is moved by the spring force of the spring 111 to the tapered valve seat 113.
And the suction valve 104 is closed.

Next, when the plunger 102 moves to the right, that is, the direction into the cylinder 101, the pressure inside the cylinder 101 increases due to the moved volume. There is a difference between the rising pressure and the external pressure (atmospheric pressure) of the discharge valve 103, and the discharge valve 103
When the received pressure is greater than the spring force of the spring 107, the check valve 108 is separated from the tapered valve seat 109, the discharge valve 103 is opened, and the liquid of the volume moved by the plunger 102 is discharged. Here, the discharge valve 103 and the suction valve 104 are sealed by a metal seal in which the tapered valve seats 109 and 113 and the tapered surfaces 115 and 116 of the check valves 108 and 112 abut.

[0005] When the pressure becomes higher than 30 kgf / cm ² , a very large receiving pressure is applied to the sealing surfaces of the suction valve and the discharge valve.
An elastic material such as rubber or resin is insufficient in strength and cannot withstand. In addition, since a sticking phenomenon occurs due to insufficient strength when a high pressure is applied, a metal seal is generally used.

[0006]

In the liquid plunger pump constructed as described above, air is present in the cylinder 101 in an initial state in which the liquid is not filled in the cylinder 101. Liquids such as oil and water have a much higher viscosity than air, so even if there is a slight gap in the metal seal surface, it can be sealed, but if air is present, air leaks and the sealing function Does not play.

At this time, if the air sealing function between the tapered valve seat 113 of the suction valve 104 and the tapered surface 116 or between the tapered valve seat 109 of the discharge valve 103 and the tapered surface 115 becomes insufficient, the cylinder The air in the cylinder 101 cannot be discharged, and even if the plunger 102 reciprocates, the pressure in the cylinder 101 does not drop sufficiently, liquid cannot be sucked in, and the liquid cannot be discharged.

The discharge valve 103 of the liquid plunger pump
If the seal portion between the valve and the suction valve 104 is a metal seal, air leakage cannot be prevented unless superfinishing such as polishing and lapping is performed on the sealing surface to improve the sealing performance. If the sealing surface is poorly processed, if a small foreign substance is caught in the sealing portion, or if the sealing surface is damaged, the sealing becomes incomplete and the cylinder 10
The air in 1 cannot be discharged, and the liquid does not discharge even if the plunger 102 reciprocates.

[0009] As the air vent in the initial state of the liquid plunger pump, the following are conventionally known. As shown in FIG. 4, an injection port 121 communicating with the cylinder 101 is provided, and a liquid is externally injected into the cylinder 101 via the injection port 121. As shown in FIG. 5, a pressure reducing valve 122 is connected to the tank 106 to apply pressure to the suction line 105 to discharge air from the discharge hole 110. Further, as shown in FIG.
6 is positioned higher than the cylinder 101 and air is discharged using the head pressure.

However, in the method of providing the injection port 121, an injection operation is required each time, and the liquid plunger pump can be installed only in a place where the injection operation can be performed. Further, in the case of applying the internal pressure to the cylinder 101 via the pressure reducing valve 122, equipment must be added, which is expensive.

Further, if the cylinder 101 itself is positioned below the liquid level of the tank 106 for air release, the arrangement is restricted.

[0012]

SUMMARY OF THE INVENTION In view of the above circumstances, the present invention is designed to discharge air existing in an initial state and discharge liquid even when the seal of a metal seal of a liquid plunger pump is deteriorated. A plunger is slidably provided in the cylinder, a discharge valve is arranged near the end of the cylinder, and a suction valve is arranged at the end of the cylinder. The discharge valve has a tapered valve seat with a tapered valve seat connected to the discharge hole. The suction valve has a tapered surface in the tapered valve seat connected to the suction hole, and the tapered surface of the check valve urged by the spring is brought into contact with the suction valve. In the liquid plunger pump, an annular mounting groove is engraved on the taper surface of the taper valve seat or the check valve, and a ring-shaped elastic sealing material having a cross-sectional shape that is easily bent at high pressure is attached to the mounting groove. Face Fitted so as to protrude,
A sealing structure for a liquid plunger pump, wherein the mounting groove is formed in a groove shape that allows the elastic sealing material to be bent at a high pressure.

[0013]

Since the suction valve and the discharge valve are provided with an elastic sealing material in combination with a metal seal, when the high pressure is applied to the elastic sealing material, the elastic sealing material itself is deformed to release the pressure. I do.

[0014]

1 shows a specific embodiment of the present invention, and FIG. As shown in FIG. 1, a plunger 2 is slidably provided in a metal cylinder 1, a discharge valve 3 is arranged near the end of the cylinder 1, and a suction valve 4 is arranged at the end of the cylinder 1. Is connected to a tank 6 via a suction line 5. Here, the discharge valve 3 is configured such that a metal check valve 8 urged by a spring 7 is seated on a tapered valve seat 9 connected to the discharge hole 10 or is separated from the tapered valve seat 9 to discharge the discharge hole of the cylinder 1. Open and close 10. In addition, the suction valve 4 allows a metal check valve 12 urged by a spring 11 to be seated on a taper valve seat 13 connected to a suction hole 14 or a taper valve seat.
The suction hole 14 of the cylinder 1 is opened and closed by moving it away from the cylinder 13. An O-ring 17 is provided on the inner surface of the cylinder 1 to maintain the sealing property between the plungers 2.

Here, when the plunger 2 moves to the left, that is, in the direction to exit from the inside of the cylinder 1, the pressure inside the cylinder 1 decreases due to the moved volume, and the external pressure of the suction valve 4 (atmospheric pressure)
And a pressure difference occurs. This differential pressure is received in the direction in which the suction valve 4 opens, and when the received pressure becomes greater than the spring force of the spring 11, the check valve 12 is separated from the taper valve seat 13 and the suction valve 4 opens. The liquid is sucked by the differential pressure, and when the differential pressure disappears, the suction valve 4 becomes a check valve.
12 is seated on the tapered valve seat 13 by the spring force of the spring 11, and the suction valve 4 is closed.

Next, when the plunger 2 moves to the right, that is, the direction into the cylinder 1, the inside of the cylinder 1 is pressed by the moved volume and the pressure rises. A difference is generated between the rising pressure and the external pressure (atmospheric pressure) of the discharge valve 3, the pressure is received in a direction in which the discharge valve 3 opens, and when the received pressure becomes larger than the spring force of the spring 7, the check valve 8 is moved to the tapered valve seat 9. The discharge valve 3 opens further away,
The liquid of the volume to which the plunger 2 has moved is discharged. Here, the seal between the discharge valve 3 and the suction valve 4 is formed by a taper valve seat 9.
This is achieved by a metal seal that abuts against the tapered surfaces 15 and 16 formed at the tips of the check valves 8 and 12.

The present invention is shown in FIG.
As shown in FIG. 7, an elastic sealing material 21 such as rubber or resin is used in combination. FIG. 2 is an enlarged view of the seal portion of the discharge valve 3 of FIG. 1, and the tapered valve seat 9 connected to the discharge hole 10 is formed so that the tapered surface 15 of the check valve 8 abuts. Here, an annular mounting groove 22 is engraved in the tapered valve seat 9, and an annular elastic sealing material 21 having a cross-sectional shape that is easily bent at high pressure is fitted so that the tip surface 21a projects from the tapered valve seat 9. Put in. When a high pressure P is applied to the distal end surface 21a of the elastic sealing material 21, the elastic sealing material 21 is set to be bent as shown by a two-dot chain line in FIG. Here, an example is illustrated, but the tip end surface 21a of the annular elastic sealing material 21 may have any cross-sectional shape as long as it is easily bent at a high pressure. To form a groove shape that allows bending.

In the above-described embodiment, the example in which the elastic sealing material 21 is provided on the tapered valve seat 9 of the cylinder 1 is described. However, the present invention is not limited to this, and the elastic sealing material 21 is provided on the tapered surface 15 of the check valve 8. A material may be fitted. At this time, the taper valve seat 9
Is not provided with an elastic sealing material. In addition, although the discharge valve 3 has been described, the suction valve 4 can be provided with an elastic sealing material in the same manner.

According to the present invention, as described above, the plunger is slidably provided in the cylinder, the discharge valve is disposed near the end of the cylinder, and the suction valve is disposed at the end of the cylinder. A check valve which has a tapered surface on a valve seat and a spring-biased check valve is brought into contact with the valve, and the suction valve has a tapered surface on a taper valve seat connected to a suction hole and is spring-biased. In the liquid plunger pump in which the tapered surface of the liquid plunger is brought into contact, an annular mounting groove is engraved on the tapered surface of the taper valve seat or the check valve, and an annular elastic sealing material having a cross-sectional shape that is easily bent at high pressure in the mounting groove. Is fitted so that the tip surface protrudes from the tapered valve seat or tapered surface,
In the sealing structure of the liquid plunger pump, wherein the mounting groove is formed in a groove shape that allows the elastic sealing material to be bent at a high pressure, the elastic sealing material is used in combination with the metal sealing material. Even if the seal of the material seal deteriorates, the air existing in the initial state can be discharged and the liquid can be discharged.

In the present invention, a metal seal requires superfinishing such as polishing or lapping, but this is not necessary because an elastic sealing material is used together. Further, in the present invention, even if a minute foreign matter is caught in the metal sealing surface, the air is not discharged from the cylinder. Furthermore, the present invention performs a sealing function by the presence of the elastic sealing material even if the metal sealing surface is damaged, and furthermore,
There is no need to vent air in the cylinder or in the line.

In addition, according to the present invention, a special injection port is provided, a pressure reducing valve is connected, or a tank is provided rather than a cylinder in order to bleed air in the initial state of the liquid plunger pump as in the prior art. There is no need to place them at high places.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an outline of a specific embodiment of a liquid plunger of the present invention.

FIG. 2 is a longitudinal sectional view of a main part of the present invention.

FIG. 3 is a longitudinal sectional view of a conventional liquid plunger pump.

FIG. 4 is a longitudinal sectional view of a conventional liquid plunger pump provided with an inlet for bleeding air in an initial state.

FIG. 5 is a longitudinal sectional view of a conventional liquid plunger pump provided with a pressure reducing valve for bleeding air in an initial state.

FIG. 6 is a longitudinal sectional view of a conventional plunger pump in which a tank is arranged at a higher position than a cylinder for bleeding air in an initial state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Cylinder 2 ... Plunger 3 ... Discharge valve 4 ... Suction valve 10 ... Discharge hole 9 ... Taper valve seat 15 ... Taper surface 7 ... Spring 8 ... Check valve 14 ... Suction hole 13 ... Taper valve seat 16 ... Taper surface 11 ... Spring 12: check valve 22: mounting groove 21: elastic sealing material

Claims (1)

(57) [Scope of request for utility model registration] 1. A plunger is slidably provided in a cylinder, a discharge valve is disposed near the end of the cylinder, and a suction valve is disposed at the end of the cylinder. The discharge valve has a tapered surface in a tapered valve seat connected to a discharge hole. The check valve is biased by a spring and the taper surface of the check valve is brought into contact.The suction valve has a taper surface in the taper valve seat connected to the suction hole, and the taper surface of the check valve biased by the spring is brought into contact. In the liquid plunger pump, the annular mounting groove is engraved on the taper surface of the taper valve seat or the check valve.
An annular elastic sealing material having a cross-sectional shape that is easily bent at high pressure is fitted into the mounting groove so that the tip surface protrudes from the tapered valve seat or the tapered surface, and the mounting groove allows the elastic sealing material to be bent at high pressure. A seal structure for a liquid plunger pump formed in a shape.