JPH02275090A - Shaft sealing device for vertical shaft pump - Google Patents

Abstract

PURPOSE:To check any bubble entrainment with a bubble separator attached to a turning shaft in the lower part of an impeller by controlling the rise of a water level in a partition pipe in utilizing a pumping action made by rotation of the impeller attached to the turning shaft. CONSTITUTION:In a through hole part of a turning shaft 3 in a discharge casing 6, there is provided a shaft sealing means 7 which holds a clearance in space with an outer circumference of this turning shaft 3. In this case, an impeller 1 is attached to the turning shaft 3, while a bubble separator 2 is fitted in a lower part of this impeller likewise. On the other hand, also there is provided a partition pipe 4 which partitions off the turning shaft 3 and a pump passage of the discharge casing 6 at the downstream side of a column pipe 5. When a water level L in the partition pipe 4 moves in the vertical direction and it has exceeded the impeller 1, a rise in the water level L is checked by a pumping action with rotation of the impeller 1. In addition, such a possibility that bubbles might be entrained with a stirring action by rotation of impeller 1 in an around a water surface is checked by the bubble separator 2.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a shaft sealing device for a vertical shaft pump, and the present invention relates to a shaft sealing device for a vertical shaft pump. This relates to a shaft sealing device for a vertical shaft pump that is suitable for water shaft sealing. [Prior art] A conventional non-sealing water shaft sealing device is disclosed in, for example, Japanese Utility Model Publication No. 63-6979.
As described in Publication No. 8, a booster impeller is attached to the pump shaft, and the pump action generated by the rotation of the booster impeller increases the pressure in the shaft seal and maintains the shaft seal at positive pressure. A method has been proposed to prevent the shaft seal from contacting rotation in a dry state.

Further, as a non-sealing water shaft sealing device having no contact portion, a technique described in Japanese Patent Application Laid-Open No. 18199/1983 is known.

In this technology, a shaft sealing vibrator is provided at the discharge casing penetration part of the pump shaft, and the pump shaft is configured to pass through this shaft sealing pipe, and the lower end of the shaft sealing vibrator maintains positive pressure during steady operation of the pump. It extends downward to the point where it becomes.

[Problem to be solved by the invention]

The technology described in the above-mentioned Japanese Utility Model Publication No. 63-69798 had to use a contact type seal in order to eliminate leakage of pumped water from the shaft seal, and required maintenance due to wear of the shaft seal. .

Also, in the technique described in Japanese Patent Application Laid-open No. 18199/1983.

Since the shaft seal part can be made non-contact, there is an advantage that maintenance associated with wear of the shaft seal part is not required.

However, as a usage condition, the pump discharge pipe forms a siphon pipe, and the water pressure inside the discharge casing provided with the shaft seal part is
Negative pressure is required.

If the discharge water level rises and the water pressure in the discharge casing becomes positive, there is a problem in that pumped water leaks from the 411# seal.

The present invention has been made to solve the problems of the prior art described above, and even when the inside of the discharge casing is under positive pressure,
To provide a shaft sealing device for an indoor shaft pump that prevents a rise in the water level in a partition pipe, prevents leakage of pumped water from a shaft seal, and eliminates the need for maintenance due to wear of the shaft seal under a wide range of operating conditions for the indoor shaft pump. This is its purpose.

[Means to solve the problem]

In order to achieve the above object, the shaft sealing device for a chamber shaft pump according to the present invention has a structure in which a shaft that maintains a gap between the rotary shaft through hole of the discharge casing of the chamber shaft pump and the outer periphery of the shaft is provided. In a shaft sealing device for a chamber shaft pump equipped with a sealing means, a partition pipe extending below the shaft sealing means and partitioning a rotating shaft and a pump flow path; It is provided with an impeller and a bubble separating plate located below the impeller and attached to the rotating shaft.

[Effect]

The function of the above technical means is as follows.

The impeller attached to the rotary shaft rotates to produce a pump action that suppresses the water level inside the partition pipe from rising, eliminating leakage of pumped water from the shaft seal.

In addition, a bubble separator plate attached to the lower part of the impeller prevents bubbles that are drawn in by the stirring action caused by the rotation of the impeller near the water surface from reaching the inside of the pump channel.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

The drawing is a longitudinal sectional view of a shaft sealing device for a chamber shaft pump according to an embodiment of the present invention.

In the figure, 1 is an impeller fitted to the rotating shaft 3, 2 is a bubble separation plate located at the bottom of the impeller 1 and fitted to the rotating shaft 3, and 4 is the rotating shaft 3 and the pump flow path. A partition pipe that separates the
Reference numeral 5 indicates a column pipe that serves as a flow path for pumped water and in which the rotating shaft 3 is disposed at part 15; 6 indicates a discharge casing that serves as a pump flow channel provided downstream of the column pipe 5; and 7 indicates rotation of the discharge casing 6. The shaft sealing means 7 is a shaft sealing means provided in the shaft through-hole, and the shaft sealing means 7 is a labyrinth seal that maintains the space between wR and the outer circumference of the rotating shaft 3.

The partition pipe 7 is in contact with the shaft sealing means 7 and functions as a shaft sealing vibrator extending below the shaft sealing means 7.

The impeller 1 and the bubble separating plate 2 are provided on the rotary shaft 3 passing through the partition pipe 7.

Next, the operation of such a chamber shaft pump will be explained.

When the pump starts moving, pumped water fills the pump channel. At this time, the water level inside the partition pipe 4 moves in the vertical direction due to the balance between the internal pressure of the discharge casing 5 acting on the lower part of the partition pipe 4 and the atmospheric pressure acting on the upper part of the partition pipe 4.

When the water level inside the partition pipe 4 exceeds the impeller 1.

The pump action generated by the rotation of the impeller 1 suppresses the rise of the water level inside the five partition pipes 4.

The bubble separating plate 2 prevents bubbles that are drawn in by the stirring action produced by the rotation of the impeller 1 near the water surface from reaching the inside of the pump channel.

According to this embodiment, even if a non-contact seal such as a labyrinth seal is adopted for the shaft seal, the discharge water level of the pump is high.
Even when the water pressure in the discharge casing becomes positive, the action of the impeller 1 has the effect of eliminating leakage of pumped water from the shaft seal portion.

〔Effect of the invention〕

As explained in detail above, according to the present invention, even when the inside of the discharge casing is under positive pressure, the rise of the water level in the partition pipe is prevented, the leakage of pumped water from the shaft seal is prevented, and the indoor shaft pump is It is possible to provide a shaft sealing device for a chamber shaft pump that can eliminate the need for maintenance due to wear of the shaft seal under a wide range of operating conditions.

[Brief explanation of drawings]

FIG. 14 is a longitudinal sectional view of a shaft sealing device for a chamber shaft pump according to an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Impeller, 2... Air bubble separation plate, 3... Rotating shaft, 4... Partition pipe, 6... Discharge casing, 7...
Shaft sealing means.

Claims (1)

[Claims] 1. In the rotating shaft through hole of the discharge casing of the vertical shaft pump,
In a shaft sealing device for a vertical shaft pump including a shaft sealing means for maintaining a gap between the shaft sealing means and the outer periphery of the rotating shaft, a partition pipe extends below the shaft sealing means and partitions the rotating shaft and the pump flow path; A shaft sealing device for a vertical shaft pump, comprising: an impeller attached to the rotating shaft; and a bubble separating plate located below the impeller and attached to the rotating shaft.