JPH07133797A - Waterless shaft sealing device for pump - Google Patents

Abstract

PURPOSE:To constitute a seal device of perfect waterless, non-lubrication, and non-cooling, and enabling a non-contact type seal device to be applied for a vertical shaft pump. CONSTITUTION:When a main shaft 3 is driven so as to rotate a vane wheel 2, water in a water tank 5 is pumped up to a drain tank 8. At this time, the pressure of pressurized water is applied on the seal part of the main shaft 3. A labyrinth seal device 10 is used on the through part of the main shaft 3 from a casing 1 to a seal chamber 9c, and an air seal device 11 is used on the through part of the main shaft 3 from the seal chamber 9c to the outward. Further a leak water pipe 4 is connected to the bottom part of the seal chamber 9c, and the extreme end of the leak water pipe is sealed by water. Hereby although a waterless seal device with no necessity for water lubrication or the like is adopted, sealing of the main shaft at starting and during operation of a pump can be performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a shaft seal device for a main shaft of a pump used for draining rainwater and the like, and a device capable of preventing leakage of water and inhalation of outside air without using lubricating water or the like. Is intended to be provided.

[0002]

2. Description of the Related Art In a pumping pump or the like in a drainage field, in order to prevent water inside the pump from flowing out of a casing penetrating portion of a pump shaft (impeller driving main shaft), a gland packing, a mechanical seal, etc. are generally used. I am using. However, these sealing devices are contact type sealing devices, and in order to maintain the sealing performance thereof, it is necessary to inject water from the outside or fill with grease or the like. Also, the actual Kaihei 4-
The one using a non-supplying water seal as a part such as 119390 is known.

[0003]

However, in the above-described gland packing or mechanical seal that has been generally used, it is necessary to supply water or grease from the outside, and especially to use the external water supply. In recent years, it has become difficult to secure a water supply source. Further, in the case of using a lubricant such as grease, it is troublesome to perform folded pattern maintenance and the like where automatic operation is desired. 4-119
No. 390 also has a waterless seal for some structures, but has a problem of wear due to the use of an oil seal, and other structures still have problems such as water leakage treatment. .

[0004]

SUMMARY OF THE INVENTION The present invention achieves a waterless seal of a main shaft of a pump without using a contact seal device.
In a pump in which the main shaft that drives the impeller is projected from the casing and a seal chamber is provided at the protruding portion, a labyrinth seal device is used for the penetrating part of the main shaft from the casing to the penetrating part to the outside. An air-sealing device is used, and a water leakage pipe is connected to the bottom of the sealing chamber, and the tip of the water leakage pipe is sealed with water. Further, a draining plate is provided on the main shaft below the air seal to prevent water leakage from splashing on the air seal.

[0005]

The device according to the present invention is constructed as described above, and therefore, when pumping the pumped water, the pumped water leaks into the seal chamber from an extremely narrow gap between the main shaft and the labyrinth seal device. The leaked water is returned to the water tank or the like through the water leak pipe. At this time, even if water leaks from the labyrinth seal device, it will not hit the water drain plate and fall, and the air seal will not come into contact with liquid and be damaged, nor will water leak from this part. Next, when the pump operation is stopped and started, the inside of the pump casing becomes negative pressure with respect to the outside air as the impeller rotates, but at this time, since the leak pipe is sealed with water, it is sealed. The outside air that enters the chamber is only from the air seal device part, and the suction amount thereof is extremely suppressed by the air seal device to enter the seal chamber.
Since the labyrinth seal prevents entry into the casing, it does not hinder pumping.
As is clear from the above description, in the present invention, even if the non-feed water seal device that does not require water lubrication or the like is adopted, the main shaft can be sealed at the time of starting and operating the pump. . Hereinafter, the present invention will be described in detail with reference to the drawings.

[0006]

1 is a schematic drawing of a water pumping apparatus according to the present invention, in which reference numeral 1 is a vertical shaft casing, 2
Is an impeller, 3 is a main shaft, 4 is a water leakage pipe for returning the water leakage to the pit 5, and the lower end thereof is opened below the water absorption level H of the pit 5. 6 is a drive motor for the impeller 2, 7 is a discharge pipe, 8 is a drain tank, and 9 is a seal box.

Next, the structure of the seal portion of the main shaft 3 will be described with reference to FIG. In FIG. 2, reference numeral 10 indicates the spindle 3.
Is a non-contact labyrinth seal provided at a portion penetrating the casing 1, and the clearance between the labyrinth seal and the through hole of the casing 1 is as small as about 0.3 mm. Code 11
Is an air seal provided in a portion where the main shaft 3 penetrates the seal box 9, and a seal ring 11a is provided in a ring-shaped groove 9a provided in the seal box 9, and the seal ring 11a is fixed to the seal box 9. At the same time, the inner hole of the seal ring 11 a is brought close to the outer peripheral surface of the main shaft 3. The clearance is about 10 microns. Reference numeral 12 is a draining plate provided on the main shaft 3 for preventing water leaking from the labyrinth seal 10 from hitting the air seal 11. Reference numeral 9b is a drainage hole for leaking water from the seal chamber 9c.

In the shaft sealing device constructed as described above, when the main shaft 3 is driven to rotate the impeller 2, the water in the water tank 5 is pumped to the drain tank 8. At this time, the pressurized water pressure acts on the seal portion of the main shaft 3. Further, when the impeller 2 is activated, the inside of the casing 1 has a negative pressure, and the outside air is not sucked from the seal portion of the main shaft 3. Therefore, in the conventional device, a gland packing or a mechanical seal is used for the seal portion of the main shaft 3, and cooling or lubrication is required.

The device according to the present invention solves the above-mentioned problem of sealing the main shaft during pump operation. First, the air seal 11 which is non-contact with the external atmospheric pressure at the time of starting is installed. By using this, cooling and lubrication are not required, and the clearance with the main shaft 3 can be narrowed to prevent outside air from entering the seal chamber 9c. On the other hand, since the leak pipe 4 is sealed with water, outside air is not sucked from here. Next, regarding the internal pressure seal during operation, the clearance between the labyrinth seal 10 and the main shaft 3 is 0.3 mm.
Since it is extremely narrow, the amount of water leakage is extremely small, and this water leakage is returned to the outside of the machine such as a pit where a pump is installed via the seal chamber 9c.

As is clear from the above description, in the device according to the present invention, the non-contact air seal and labyrinth seal are used to completely suck the outside air and leak water during the operation of the pump without disturbing the operation. It could be prevented. 3 and 4 show another example of use of the device according to the present invention. In FIG. 3, the water leak pipe 4 is water-sealed by a water leak tank provided outside. FIG. 4 shows a case where the present invention is applied to a horizontal shaft type pump, and the horizontal shaft pump can also cope with intake air at the start of operation and water leakage during operation.

[0011]

As described above, in the shaft sealing device according to the present invention, the non-contact type sealing device such as the air seal and the labyrinth seal is used to form a completely non-water-filling, non-lubricating, non-cooling sealing device. In addition, the non-contact type sealing device can be used even in a vertical shaft pump in which the pressure inside the pump at the shaft sealing part is positive or negative by sealing the return pipe of the leak water provided in the seal chamber. Is.

[Brief description of drawings]

FIG. 1 is a schematic overall side view of a waterless shaft sealing device according to the present invention.

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

FIG. 3 is a schematic side view of an installation example of a water leak pipe of the waterless shaft sealing device according to the present invention.

FIG. 4 is a schematic overall side view of another embodiment of the waterless shaft sealing device according to the present invention.

[Explanation of symbols]

 1 Casing 2 Impeller 3 Main shaft 4 Water leak pipe 9c Seal chamber 10 Labyrinth seal 11 Air seal 12 Drain plate

Claims (2)

[Claims] 1. A pump in which a main shaft 3 for driving an impeller 2 is protruded from a casing 1 and a seal chamber 9c is provided at a protruding portion of the main shaft 3.
The labyrinth seal device 10 is used for the penetrating portion to c, the air seal device 11 is used for the penetrating portion of the main shaft 3 from the seal chamber 9c to the outside, and the leak pipe 4 is connected to the bottom of the seal chamber 9c. A non-water-supplying shaft sealing device for a pump in which the tip of the pipe 4 is sealed with water. 2. A waterless shaft sealing device for a pump in which a water drain plate 12 is provided on a main shaft 3 below the air seal device 11.