JPH0676690U - Shaft seal device - Google Patents

Abstract

(57) [Summary] [Purpose] While not rotating during rotation to prevent a decrease in life due to wear, even if there is a leak from the labyrinth seal due to an increase in the suction water level when rotation is stopped, this leaks to the outside. Be sure to prevent it from coming out. [Structure] It is possible to elastically contact a conical, large-diameter peripheral surface portion 8a of a lower large-diameter peripheral surface portion 8a of a rotary shaft 2 located axially outside the labyrinth seal 6 with a fixed annular seal surface portion 7 of the casing 1 side. A fixed annular seal body 8 is fixed to the lower large-diameter peripheral surface portion 8a of the annular seal body 8 due to centrifugal force when the rotary shaft 2 rotates.
Weight member 9 for separating a from the fixed annular seal surface portion 7
Are attached together.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention mainly relates to a shaft sealing device used in a rotary machine having a rotary shaft penetrating a casing, such as a vertical shaft pump.

[0002]

[Prior art]

 For example, in a vertical shaft pump, as shown in FIG. 3, a rotary shaft 104 for driving and rotating an impeller 103 in a casing 102 arranged vertically is inserted into the casing 102 in a vertical posture. The base end side of the rotary shaft 104 penetrates the upper end wall of the casing 102 and projects upward. Therefore, a shaft sealing device 105 is provided between the rotary shaft 104 and the upper end wall portion of the casing 102 (a penetrating portion of the rotary shaft).

As the shaft sealing device 105, conventionally, as shown in FIG. 4, a labyrinth seal 106 as a non-contact seal is fitted and held in a through hole 107 in a casing 102 so that the shaft is not connected to the rotary shaft 104. A liquid seal between the rotating shaft 104 and the casing 102 in a contact state has been adopted.

[0004]

[Problems to be solved by the device]

 According to the conventional shaft sealing device using the labyrinth seal 106 as described above, when the pump suction is stopped and the vertical pump suction water level is the normal level WL shown in FIG. 3, water leaks from the labyrinth seal 106. Although it is not discharged, when the suction water level becomes higher than the shaft sealing position HWL, water leaks from the gap between the labyrinth seal 106 and the rotating shaft 104, and the pump floor 108 becomes in a flooded state. There was a fear that

The present invention has been made to solve the above-mentioned problems, and by adding a simple structure, the rotating shaft is brought into non-contact during rotation, thereby causing no wear and an increase in rotational resistance. The object of the present invention is to provide a shaft seal device that can reliably prevent water from leaking when rotation is stopped.

[0006]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, a shaft sealing device according to the present invention is a shaft sealing device in which a non-contact seal is provided at a penetrating portion of a rotating shaft in a casing, in which the non-contact seal is positioned in the axial direction more than the installation position. An annular seal body made of an elastic material, which is formed in a conical shape and has a larger diameter toward the lower side, is fixed to the rotating shaft at the upper position, and the lower large-diameter peripheral surface portion of this annular seal body elastically contacts. A fixed annular seal surface is provided on the casing side, and the lower large-diameter peripheral surface portion of the annular seal body has a larger specific gravity than the annular seal body, and when the rotation shaft stops rotating, the annular seal body is The lower large-diameter peripheral surface portion of the annular seal body is pressed against the fixed annular seal surface portion by the elastic force and the additional load, and when the rotary shaft rotates, the lower large-diameter peripheral surface portion of the annular seal body is attached by centrifugal force. Is the above fixed annular seal face part The weight member of separating is obtained by integrally mounted.

[0007]

[Action]

 According to the present invention, when the rotation of the rotating shaft is stopped, the lower large-diameter peripheral surface portion of the annular seal body is pressed against the fixed annular seal surface portion by the additional load of the weight member and the elastic force of the annular seal body. Due to the close contact, the space between the rotary shaft and the casing is sealed by an annular seal body. Therefore, for example, even when the pump suction water level is higher than the shaft sealing position, the sealing action described above can prevent water leakage to the outside. Further, when the rotating shaft rotates, the lower large-diameter peripheral surface portion of the annular seal body is separated from the fixed annular seal surface portion by the centrifugal force acting on the weight member, and the rotating shaft and the casing do not come into contact with each other. It is possible to suppress the functional deterioration of the shaft sealing device due to the wear of the annular seal body and the annular seal surface portion. In addition, smooth rotation can be maintained with little power consumption and no increase in rotation resistance.

[0008]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. 1 and 2 are vertical cross-sectional views when a shaft sealing device according to an embodiment of the present invention is applied to a vertical shaft pump. FIG. 1 shows an operation stopped state, and FIG. 2 shows an operation state.

In FIG. 1 and FIG. 2, reference numeral 1 denotes a casing that supports the rotating shaft 2 through it, and includes a casing body 3 and a cover 4. A labyrinth seal 6 as a non-contact seal fitted on the rotary shaft 2 is held in the rotary shaft through hole 5 of the casing body 3 to seal the rotary shaft through hole 5. At the same time, the outer peripheral surface of the cover 4 is configured as a fixed annular seal surface portion 7.

An annular seal body 8 formed in a conical shape having a larger diameter on the lower side is fixed to the rotary shaft 2 above the cover 4. The annular seal body 8 is made of an elastic material such as rubber so that the large-diameter peripheral surface portion 8a on the lower side thereof comes into elastic contact with the fixed annular seal surface portion 7. Further, a weight member 9 made of metal or the like having a larger specific gravity than the annular seal body 8 is integrally attached to the outer side of the large-diameter peripheral surface portion 8a on the lower side of the annular seal body 8. As a result, when the rotation of the rotary shaft 2 is stopped, the elastic force of the annular seal body 8 and the additional load of the weight member 9 cause the lower large-diameter peripheral surface portion 8a to be pressed and brought into close contact with the fixed annular seal surface portion 7. Further, when the rotating shaft 2 rotates, the lower large-diameter peripheral surface portion 8a of the annular seal body 8 is separated from the fixed annular seal surface portion 7 by the centrifugal force acting on the weight member 9.

Next, the operation of the above configuration will be described. When the rotation shaft 2 is stopped, the lower large-diameter peripheral surface portion 8a of the annular seal body 8 is pressed against the fixed annular seal surface portion 7 by the elastic force of the annular seal body 8 and the additional load of the weight member 9. Due to the close contact, the space between the rotary shaft 2 and the casing 1 is sealed. Therefore, even if the suction water level becomes higher than the installation position of the labyrinth seal 6 and water leaks from the labyrinth seal 6, the leaked water will not leak out due to the liquid sealing action of the annular seal body 8. Can be stopped. As a result, there is no risk of water leaking into the pump floor. When the drain pipe 10 is provided for maintenance, the opening / closing valve 11 is provided in the drain pipe 10 and the opening / closing valve 11 is normally closed.

Further, when the rotary shaft 2 rotates, the lower large-diameter peripheral surface portion 8 a of the annular seal body 8 is separated from the fixed annular seal surface portion 7 by the centrifugal force acting on the weight member 9, so that the annular seal body 8 is rotated. And the annular sealing surface 7 are in a non-contact state where no friction occurs. That is, when the pump is in operation, the rotary shaft penetrating portion of the casing 1 is sealed by the non-contact sealing function of the labyrinth seal 6, while the liquid sealing function of the annular sealing body 8 and the annular sealing surface 7 is worn. The decrease can be suppressed, and the rotation resistance acting on the rotating shaft 2 is small, so that a smooth rotation state can be secured.

Although the above embodiment has been described by applying it to the vertical shaft pump, the bearing device of the present invention can be applied to a rotary machine for fluid other than the vertical shaft pump.

[0014]

[Effect of device]

 As described above, according to the present invention, by simply adding a simple structure such as fixing an annular seal body with a weight member to the rotary shaft on the axial upper side of the non-contact seal, when the rotary shaft stops rotating. By the additional load of the weight member and the elastic force of the annular seal body, the lower large-diameter peripheral surface portion of the annular seal body is pressed and brought into close contact with the fixed annular seal surface portion to seal between the rotary shaft and the casing. Even if the fluid pressure inside the casing rises due to an abnormal rise in the pump suction water level and there is a leak from the non-contact seal, water leakage to the outside can be reliably prevented, and the specified shaft seal Function can be secured. Even so, when the rotary shaft rotates, the lower large-diameter peripheral surface portion of the annular seal body is reliably separated from the fixed annular seal surface portion by the centrifugal force acting on the weight member, so that the rotary shaft and the casing do not come into contact with each other. As a result, it is possible to suppress deterioration of the function of the shaft sealing device due to wear of the annular seal body and the annular seal surface portion, to prolong the service life of the shaft sealing device, increase rotation resistance, and reduce power consumption and smooth operation. You can keep a good rotation.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a shaft seal device according to an embodiment of the present invention applied to a vertical shaft pump in a stopped state.

FIG. 2 is a vertical cross-sectional view showing the shaft seal device in the same embodiment in an operating state of a vertical shaft pump.

FIG. 3 is a schematic configuration diagram of a usage state of the vertical shaft pump.

FIG. 4 is a vertical sectional view showing a conventional shaft sealing device.

[Explanation of symbols]

 1 casing 2 rotating shaft 6 labyrinth seal 7 fixed annular seal surface portion 8 annular seal body 8a lower large diameter peripheral surface portion 9 weight member

Claims (1)

[Scope of utility model registration request] 1. A shaft sealing device, wherein a non-contact seal is provided in a penetrating portion of a rotary shaft in a casing, wherein the diameter of the rotary shaft at an axial upper position relative to the installation position of the non-contact seal becomes larger toward the lower side. An annular seal body made of an elastic material formed into a conical shape is fixed, and a fixed annular seal surface with which the lower large-diameter peripheral surface portion of the annular seal body elastically contacts is provided on the casing side. The lower large-diameter peripheral surface portion of the annular seal body has a larger specific gravity than that of the annular seal body, and when the rotation shaft stops rotating, the lower large-diameter peripheral surface portion is formed by the elastic force and the additional load of the annular seal body. A weight member is attached integrally to the fixed annular seal surface portion so as to press and closely contact, and when the rotating shaft rotates, centrifugal force causes the lower large-diameter peripheral surface portion of the annular seal body to separate from the fixed annular seal surface portion. Special A shaft seal device to be collected.