JP2007146707A - Mechanical seal device for pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mechanical seal device for a pump without water leak from the mechanical seal device of the seal chamber which occurs at a time of pump operation stop and re-operation. <P>SOLUTION: The mechanical seal device for the pump is provided with a casing 42 including a pump part 62 and a bearing 50 supporting the drive shaft 64 therein, and includes a seal chamber 63 storing a mechanical seal device 63a between the pump part 62 and the bearing 50 in the casing 42. The mechanical seal device 63a is provided with a first seal member 65 and a second seal member 68. A projection 43 projecting radial direction inward is formed in the seal chamber 63 of the casing 42. A projection top part 43a is formed radially inside of an outer radius 69a of a second seal member 68, and an end surface of the projection 43 in a second seal member 68 direction abuts on a slide surface 69b of a second axial seal part 69. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention includes a casing having a pump portion and a bearing that supports a drive shaft of the pump portion therein, and has a seal chamber that houses a mechanical seal device between the pump portion and the bearing in the casing, The mechanical seal device includes a first seal member that seals a radially outer periphery of the drive shaft, and a second seal member that seals a radially inner surface of the seal chamber. An outer peripheral seal portion that seals the drive shaft and a first axial seal portion that seals the sliding surface in cooperation with the second seal member, and the first axial seal portion is second by a spring. The inner diameter seal portion that seals the inner surface of the seal chamber of the second seal member and the radially inner portion of the inner diameter seal portion are provided integrally with the first seal member. About the mechanical seal device of a pump and a second axial sealing portion having a sliding surface in the direction seal portion and the axial direction.

FIG. 2 is an example of an automatic water supply circuit using a carbonator in which a pump having a mechanical seal device of the present invention is used. A carbon dioxide gas cylinder 1 with a regulator is connected to a water tank 6 by an air supply pipe L1, The water tank 6 is connected to an electromagnetic valve 8 by a pipe 10, and the electromagnetic valve 8 is connected to the suction port 3 of the pump 2 by a suction pipe 12.
The discharge port 4 of the pump 2 is connected to a carbonator 18 that produces carbonated water through an electromagnetic valve 16 that is adjusted to an appropriate amount by a discharge pipe 14. It is connected to supply.

FIG. 3 is a diagram showing a cross-sectional configuration of the pump 2 used in FIG.
A rotor 21 supported by a bearing 20 so as to be rotatable by a drive shaft 24 is accommodated in a pump portion 22 of the casing 2a, and a seal chamber 23 having a mechanical seal 23a is provided between the pump portion 22 and the bearing 20. It has been.
The drive shaft 24 penetrating the seal chamber 23 is arranged to be connected to an external drive source (not shown).

As is well known, the mechanical seal 23a is formed of a first seal member 25 and a second seal member 28, and the first seal member 25 seals between the drive shaft 24 and the second seal member 25. The seal member 28 seals the drive shaft 24 radially outward.
Here, the first seal member 25 includes a retainer 27a, and an elastic seal material 26 and a carbon material 27 surrounded by the retainer 27a. The second seal member 28 includes an elastic seal material 31 and an elastic seal material 31. It is comprised with the ceramic 29 of the sliding material enclosed by.

Then, the first seal member 25 is pressed in the direction of the second seal member 28 by the coil spring 27b, and the carbon material 27 and the ceramic 29 are in close contact with each other to perform a seal function.
The elastic sealing material 26 and the drive shaft 24 are in close contact with each other, and serve to seal the drive shaft 24. The spring force of the coil spring 27b compensates for a decrease in seal pressure due to wear of the carbon material 27.

FIG. 4 is a view for explaining a state in which the sealing function of the conventional mechanical seal 23a is incomplete.
If the pump 2 in the operating state is stopped and the electromagnetic valve 8 in FIG. 2 is simultaneously closed and the water absorption from the water tank 6 is stopped, the electromagnetic valve 8 is instantly closed. The pump 2 does not stop rotating abruptly like a step by inertia of the rotor 21, the motor of the drive source, and the drive shaft 24.

  Therefore, the suction pipe 12 in FIG. 2 and the seal chamber 23 in FIG. 3 are in a high vacuum, and the second seal member 28 moves to the right in FIG. As the second seal member 28 moves to the right, the first seal member 25 also moves to the right against the tight pressure between the coil spring 27b and the elastic member 26 and the drive shaft 24.

  Next, when the pump 2 is rotated again, the electromagnetic valve 8 is opened, the vacuum state of the seal chamber 23 is released, and the second seal member 28 immediately returns to the left in the normal position in FIG. However, the first seal member 25 cannot move following the second seal member 28 in real time even if there is a spring force of the coil spring 27b because the pressure of the elastic member 25 in close contact with the drive shaft 24 is large. .

  FIG. 4 is an explanatory view showing the state at that time, and the second seal member 28 returns to the normal position, and the first seal member 25 is delayed in following. Then, a gap is generated between the end contact surface 29a of the ceramic 29 and the end contact surface 27a of the carbon material 27, and a water leakage flow 23a is generated and flows into the bearing 20 direction. And it leaks outside.

As a device for preventing the gear pump feed from flowing into the bearing portion, a technology is disclosed in which a casing for housing the drive shaft and the driven shaft is divided into two in a gear pump having a drive shaft and a driven shaft. (For example, refer to Patent Document 1).
Also, various techniques for the gear pump are disclosed (for example, see Patent Documents 2 and 3).
JP-A-2005-194909 JP-A-2005-36656 JP 2005-133557 A

  The present invention has been proposed in view of the above-mentioned problems of the prior art, and provides a mechanical seal device for a pump that is free from water leakage from the mechanical seal device in the seal chamber caused by stopping and re-operation of the pump. For the purpose.

  As a result of various studies, the applicant of the present invention does not impair the sealing effect of the mechanical seal even if the pump operation is stopped and the solenoid valve 8 connected to the pump suction pipe is simultaneously closed and the seal chamber is in a vacuum state. Invented a mechanical seal device for a pump. The present invention has been created by such research.

  According to the mechanical seal device of the pump of the present invention, the casing 42 having the pump portion 62 and the bearing 50 that supports the drive shaft 64 of the pump portion 62 is provided inside, and the pump portion 62 and the bearing 50 in the casing 42 are provided. Between the first seal member 65 for sealing the outer periphery in the radial direction of the drive shaft 64 and the inside of the seal chamber 63 in the radial direction. And a second seal member 68 that seals the inner surface 42c, and slides in cooperation with the outer seal portion 66 that seals the drive shaft 64 of the first seal member 65 and the second seal member 68. A first axial seal portion 67 that seals the surface is provided, and the first axial seal portion 67 is a second seal member 68 by a spring 67b. The inner diameter seal portion 71 that seals the inner surface 42c of the seal chamber 63 of the second seal member 68 and the radially inner side of the inner diameter seal portion 71 are integrally provided in the first axial direction. In the mechanical seal device of the pump having the seal portion 67 and the second axial seal portion 69 having the sliding surface 69b in the axial direction, a protrusion 43 protruding radially inward into the seal chamber 63 of the casing 42 is provided. The protrusion top 43 a is formed radially inward from the outer radius 69 a of the second seal member 68, and the end surface of the protrusion 43 in the second seal member 68 direction is the second axial seal portion 69. It is in contact with the sliding surface 69b.

    In implementation, it is important to assemble the end surface of the protrusion in the second seal member direction and the sliding surface 69b of the second axial seal portion in close contact with each other without any gap.

The effects of the mechanical seal device of the pump of the present invention described above will be listed.
(1) An annular protrusion is formed in the seal chamber, the protrusion height is formed radially inward from the outer radius of the second seal member, and the end surface of the protrusion in the second seal member direction is the second axial direction. Since it is in contact with the end face of the seal portion, the pump is stopped and the solenoid valve provided in the water absorption pipe is closed at the same time, and the second seal member is blocked by the protrusion even if the seal chamber is evacuated. There is an advantage that water does not occur without moving in the room direction.

(2) Unlike the conventional sealing method in which a vacuum is generated each time the pump is stopped and the outer peripheral seal portion 66 is worn by sliding between the drive shaft and the outer peripheral seal portion, the above configuration causes the outer seal portion to There is an advantage that wear resistance due to movement is eliminated and durability of the outer peripheral seal portion is increased.

Hereinafter, an embodiment of a mechanical seal device for a pump according to the present invention will be described with reference to the drawings.
FIG. 1 is a sectional view of a mechanical seal device for a pump according to the present invention.
A pump portion 62 and a drive shaft 64 for driving the rotor 51 of the pump portion 62 are disposed inside the pump casing 42, the entire structure being represented by reference numeral 41.

A seal chamber 63 is provided adjacent to the pump portion 62, and the drive shaft 64 passes through the seal chamber 63 and is connected to a motor (not shown) which is an external power source.
A bearing 50 that supports the drive unit 64 is provided outside the seal chamber 63, and a mechanical seal device 63 a for sealing water leakage from the seal chamber 63 toward the bearing 50 is accommodated in the seal chamber 63. .

  The mechanical seal device 63 a includes a first seal member 65 that seals the outer periphery in the radial direction of the drive shaft 64, and a second seal member 68 that seals the radially inner surface 42 c of the seal chamber 63. Yes.

  The first seal member 65 includes an outer peripheral seal portion 66 that seals the outer peripheral surface 64a of the drive shaft 64 and a first axial seal portion 67 that cooperates with the second seal member 68 to seal the sliding surface. It is comprised by the retainer 67a, and is comprised integrally.

  The first axial seal portion 67 is pressed in the direction of the second seal member 68 via the retainer 67a by a coil spring 67b supported by a dish-shaped cage 67c in contact with the end of the pump portion 62. .

  The second seal member 68 includes an inner diameter seal portion 71 that seals the inner surface 42c of the seal chamber 63, and a second axial seal portion 69 that is integrally provided radially inward of the inner diameter seal portion 71. Has been.

  As described above, the second axial seal portion 69 has the sliding surface 69b in contact with the first axial seal portion 67 in the axial direction.

  In the illustrated example projecting radially inward in the seal chamber 63, an annular protrusion 43 is formed, and the protrusion top 43 a is formed radially inward from the outer radius 69 a of the second seal member 68. . That is, the relationship of radius r2 which is the outer radius 69a> radius r1 of the top portion 43a is established, so that the second seal member 68 prevents the seal chamber 43 from moving in the right direction in the drawing. The protrusion 43 does not necessarily have an annular shape, and may be a plurality of intermittent protrusions.

  An end surface 43 b of the protrusion 43 in the direction of the second seal member 68 is formed so as to contact the sliding surface 69 b of the second axial seal portion 69.

The operation of the mechanical seal device of the pump having the configuration of FIG. 1 will be described below with reference to the circuit diagram of FIG.
The pump 41 in operation is stopped simultaneously with the closing of the electromagnetic valve 8 at the end of the water suction pipe 12 leading to the pump 62 (2 in FIG. 2) as in a normal operation.

  Since the pump unit 62 of the pump 41 is stopped by shutting off the power source of the motor of the drive source, even if the electromagnetic valve 8 is closed, the inertia of the motor, the drive shaft 64 and the rotor 51 of the pump unit 62 (rotational inertia). The pump unit 62 is not immediately stopped and continues to rotate.

  Between the closing of the electromagnetic valve 8 and the stop of the pump unit 62, the water absorption pipe 12 and the seal chamber 63 are in a vacuum state, and the degree of vacuum increases according to the time until the pump unit 62 stops.

  In the conventional mechanical seal device of the pump shown in FIG. 3, the second seal member 68 compresses the coil spring 67 b in accordance with the degree of vacuum in the seal chamber 63, and the pump portion 62 together with the first seal member 65. Move in the direction. When the operation is resumed, a gap is formed between the second seal member 68 and the first seal member 65 as in FIG.

  However, regardless of the degree of vacuum of the seal chamber 63 due to the annular protrusion 43 in FIG. 1, the second axial seal portion 69 of the second seal member 68 is blocked by the protrusion 43 and does not move. Accordingly, the second axial seal portion 69 of the second seal member 68 and the first axial seal portion 67 of the first seal member 65 are in close contact with each other, and water leakage does not occur when the operation is resumed.

It is a composition sectional view showing an embodiment of a mechanical seal device of a pump of the present invention. It is an automatic water supply circuit diagram which shows an example of the environment where the mechanical seal apparatus of the pump of this invention is used. It is a structure sectional view showing the mechanical seal device of the conventional pump. It is explanatory drawing which shows the malfunction of the mechanical seal apparatus of the conventional pump of FIG.

Explanation of symbols

42... Casing 42 c ... Inner surface 43 ... Projection 43 a ... Top 43 b ... End face 50 ... Bearing 62 ... Pump part 63 ... Seal chamber 63a ... Mechanical seal device 64 ... Drive shaft 65 ... First seal member 66 ... Outer peripheral seal portion 67 ... First axial seal portion 67a ... Retainer 67b ... Spring 68 ... Second seal member 69 ... Second axial seal portion 69a ... Outer diameter 69b ... Sliding surface 71 ... Inner diameter seal portion

Claims (1)

  A casing having a pump part and a bearing for supporting a drive shaft of the pump part is provided inside, and a seal chamber is provided between the pump part and the bearing in the casing to accommodate a mechanical seal device. Comprises a first seal member that seals the outer periphery in the radial direction of the drive shaft and a second seal member that seals the radially inner surface of the seal chamber, and seals the drive shaft of the first seal member A first axial seal portion that seals the sliding surface in cooperation with the outer peripheral seal portion and the second seal member, and the first axial seal portion of the second seal member is provided by a spring. The inner diameter seal portion that seals the inner surface of the seal chamber of the second seal member and the radially inner portion of the inner diameter seal portion, and is provided integrally with the first axial seat. And a second axial seal portion having a sliding surface in the axial direction, wherein a projection protruding radially inward is formed in the seal chamber of the casing, and the top of the projection is The pump is characterized in that it is formed radially inward from the outer radius of the second seal member, and the end surface of the projection in the second seal member direction is in contact with the sliding surface of the second axial seal portion. Mechanical seal device.

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