JPH0697053B2 - Journal bearing for pump and pump using the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a journal bearing for a pump used in a liquid and a gas and a pump using the same, and particularly, to a bearing in the air at the time of starting and stopping. The present invention relates to a submerged bearing of a vertical axis pump or an oblique axis pump that slides in water or slurry during steady operation and a pump using the bearing.

[Conventional technology]

Rubber bearings, lead bronze bearings, and other bearings have been used as submerged bearings for conventional vertical shaft pumps and oblique shaft pumps. However, when starting these pumps, the submersible bearings were often placed in gas, and it was difficult to start the pumps as they were. That is, both rubber bearings and metal bearings such as lead bronze show extremely stable sliding characteristics if used in a state of being lubricated with water or oil, but in a gas, that is, under unlubricated conditions. This is because when it is used, the sliding portion heats up violently and the bearing portion is quickly damaged.

Therefore, in the conventional vertical shaft pump or oblique shaft pump, in order to protect the submersible bearing during operation under a non-lubricated condition at the time of starting, means such as supply of lubricating oil or water injection to the bearing portion has been adopted.

FIG. 1 shows an outline of a conventional vertical shaft pump provided with a device for injecting water into the bearing portion. To explain the outline, FIG. 1 shows the external water level 1 and the position where the external water level 1 is submerged. The pump is installed so that the impeller 2 comes in. The drive motor 3 is provided on land for easy maintenance and inspection, and the rotation of the drive motor 3 is transmitted through the shaft coupling 4 to the shaft 5,
It is transmitted to 5 ', and the impeller 2 connected to the tip of the shaft 5'is rotated. Reference numeral 6 is an intermediate shaft coupling that connects the shaft 5 and the shaft 5 '. Water is sucked from the suction bell 7 by the rotation of the impeller 2, passes through the discharge bowl 8, the hanging pipes 9 and 10, and is discharged from the discharge elbow 11. 12, 13
Is a protective tube for guiding lubricating water to the upper submerged bearing 14 and the lower submerged bearing 15. In addition, the upper submerged bearing 14 supports the submerged bearing.
Lower submersible bearing 15 is supported by ribs 17,1
Supported by 7 '.

Next, the upper submerged bearing 14 will be described with reference to FIG.
FIG. 2 is an enlarged view of the upper submerged bearing 14 in FIG. 1. A cylindrical sleeve 18 made of stainless steel is fixed to the shaft 5 ′ so that it can rotate integrally with the shaft 5 ′. ,
Further, a rubber bearing 19 is fixed to the underwater bearing support 16 with a slight clearance from the outer peripheral surface of the sleeve 18. The inner peripheral shape of the horizontal cross section of the rubber bearing 19 is circular, and is generally provided with several vertical grooves for lubricating water. The radial deflection of the shafts 5, 5'caused by the rotation of the shafts 5, 5'is restricted by the outer peripheral surface of the sleeve 18 slidingly contacting the inner peripheral surface of the rubber bearing 19.

From the water injection port 20 (see FIG. 1) to the shaft when the conventional vertical shaft pump shown in FIG. 1 and FIG.
Water is injected between 5, 5'and the protection tubes 12, 13 and submerged bearings 14, 15
Is to be protected by lubricating it with water. The vertical shaft pump shown in Fig. 1 is provided with two submersible bearings, an upper submerged bearing 14 and a lower submerged bearing 15, as submersible bearings, but the shaft length of the vertical pump can reach several tens of meters. In that case, many submerged bearings are provided. A protective tube is provided over the entire length of the shaft to protect all the underwater bearings in the meantime. Therefore, not only a great amount of equipment cost is required to protect the submersible bearings at the time of starting the pump in this way, but also the weight of the entire pump becomes large, so a large amount of equipment cost is also required for the device for supporting the pump. I was forced to.

Although the description based on FIG. 1 and FIG. 2 is about the vertical shaft pump, the oblique shaft pump also has the same problem.

[Object of the Invention]

An object of the present invention is to provide a journal bearing for a pump used in a gas and a liquid, which has stable sliding characteristics under both usage conditions, and a pump using the journal bearing. In particular, as a submersible bearing for vertical pumps and oblique shaft pumps, it can be started even under unlubricated conditions when the pump is started, and exhibits good sliding characteristics even during steady operation after starting. A journal bearing for a pump that exhibits stable sliding characteristics even in a highly conductive liquid such as seawater or a slurry liquid, and a pump using the journal bearing.

[Structure of Invention]

1. In a pump device in which the pump shaft is passed through the channel of the liquid to be handled by the pump, the pump shaft is provided so as to be exposed in the channel of the liquid to be handled, and is lubricated in the liquid to be handled and air in the channel, and its rotating member is made of tungsten A journal bearing for a pump, characterized in that it is made of a cemented carbide with a carbide (WC) content of 90% by weight or more, and the stationary member is made of ceramics made of silicon nitride (Si ₃ N ₄ ) or silicon carbide (SiC), And 2. Tungsten carbide (WC) content of the rotating side member is 90
A pump journal bearing, which is made of cemented carbide of at least wt.% And whose stationary side member is made of ceramics made of silicon nitride (Si ₃ N ₄ ) or silicon carbide (SiC), is rotated in the handling liquid and air. A pump configured such that at least one pump shaft is provided above, and the pump shaft is passed through a flow path of a liquid to be handled by the pump.

The present inventors have made it possible to start the pump in a gas, that is, under a non-lubricated condition, and further show stable sliding characteristics in seawater or slurry liquid. As a result of earnest studies on bearings, the present invention has been completed.

Hereinafter, the present invention will be described in detail.

It is desirable that the submersible bearings of the vertical shaft pump or the oblique shaft pump stably exhibit good sliding characteristics under both unlubricated conditions and lubricated conditions as described above.
However, the combination of sliding members in conventional underwater bearings,
For example, in the case of rubber bearings-stainless steel shaft sleeves or carbon-containing Teflon bearings-stainless steel shaft sleeves, the sliding properties in clear water are excellent, but they cannot be used at all under no-lubrication conditions. In the combination of carbon bearings or carbon-containing copper alloy bearings and stainless steel shaft sleeves, if the underwater bearing is immersed in a slurry liquid containing silica sand (alumina particles), the sliding surface will be damaged promptly. , I wasn't necessarily satisfied.

The present inventors conducted a test using the experimental apparatus shown in FIG. 3 and used a vertical shaft pump as shown in FIG. 5 to test various journal bearings for fresh water condition, gas condition, slurry condition, seawater condition or slurry. As a result of investigating the sliding characteristics in various usage environments such as seawater conditions including, it was found that the journal bearing of the present invention is the most excellent.

First, FIG. 3 will be described.

FIG. 3 is a vertical sectional view of the sliding test device.

In FIG. 3, a shaft 23 is rotated by a hydraulic motor 21 via a torque meter 22, and a sleeve-shaped test piece is attached to the end of the shaft 23.
A ring-shaped test piece 26, in which 25 is fitted and fixed, and the test piece 25 is slidably fitted in, is fitted in the bearing house 27, and the radial load applied from the direction indicated by the arrow 30 is applied to the rod via the load cell 28. It is transmitted to the holding member 31 of the bearing house 27 through the 29 end. The bearing house 27 is provided with a hose 33 into which the liquid is fed from the arrow 32. 34 is a tachometer for knowing the number of rotations of the shaft 23.

The bearing house 27, the load cell 28, the rod 29, the bearing house holding member 31, the hose 33, etc. on the side supporting the ring-shaped test piece (diameter 60 mm, width 10 mm) 26 are in the test tank 35.
The test tank 35 is supported by a vertically movable rod 37 of a vertical feed device 36. Therefore, ring-shaped test piece
26 moves up and down, the sleeve-shaped test piece 25 rotates, and liquid can be sent into the bearing gaps between them.

Table 1 shows the data obtained by this sliding tester.

The materials used are as follows.

Cemented Carbide ... JIS H 5501 G Class 3 containing 90% or more WC
No. Stainless steel …… SUS 304 stainless steel Hard facing material …… Slurry water containing 35% WC …… SiO _{2 with} average particle size 80μ and maximum particle size 100μ
Water containing 0.3% by weight River water + slurry ... 0.3% by weight of river sand and average particle size 80
μ, water containing 0.3% by weight of Al ₂ O _{3 with} a maximum particle size of 100 μ Seawater + slurry …… SiO with an average particle size of 80 μ and a maximum particle size of 100 μ
Seawater Table 1 in No.1,2 containing ₂ 0.3 wt% is pump journal bearings of the present invention, Nanba3～10 is a journal bearing for a conventional journal bearing and comparative tests.

The symbols in the evaluation columns are: ◎ ... Sufficient durability (16,000 hours or more) ○ ... Practical use (8,000 hours or more) △ ... Usable under some conditions × ... Unusable, friction coefficient The results of comprehensive evaluation of various factors such as wear resistance, seizure resistance and the like are shown.

A number of tests were conducted on bearings other than the above combinations, but these data were omitted.

Fig. 4 shows operating time on the horizontal axis and friction coefficient on the vertical axis. Sliding speed is 2.5 m / s and surface pressure is 6.3 kgf / cm ² for rubber bearing vs. stainless steel SUS304 (symbols marked with ×). ), 67 for silicon nitride ceramic bearings vs. cemented carbide (90% WC)
67 kgf / cm ² (Invention 1 represented by symbol ○), silicon carbide ceramic bearing vs. cemented carbide (90% WC)
kgf / cm ² (Invention 2 represented by symbol *) and 42 kgf / c
The results of the test conducted with m ² (invention 2 ′ represented by the symbol *) are shown.

As is clear from Table 1 and FIG. 4, the journal bearing for a pump of the present invention, that is, the journal bearing for a pump in which a cemented carbide and silicon nitride ceramics or silicon carbide ceramics are combined, is Quartz sand
It exhibits extremely stable sliding characteristics even in a slurry liquid containing alumina particles.

The silicon nitride or silicon carbide ceramics used as a member in the present invention has very high compressive strength but low tensile strength, and has a mechanical property different from that of a metal material such as a small linear expansion coefficient. When it is used, by fixing it in a metal case by shrink fitting, etc., the advantages of the above properties can be utilized and the drawbacks can be sufficiently compensated.

The cemented carbide used in the tests shown in Table 1 and FIG. 4 is equivalent to JIS H5501 G type 3 but contains 90 wt% or more of tungsten carbide (WC). If so, it has good and stable sliding characteristics as shown in Table 1 and FIG.

FIG. 5 shows a schematic vertical sectional view of a vertical shaft pump of the present invention corresponding to the vertical shaft pump shown in FIG.

In FIG. 5, each symbol has the same meaning as each symbol shown in Table 1.

Since the journal bearing of the present invention exhibits stable sliding characteristics in air, clear water, or slurry liquid containing various particles, when applied to a vertical shaft pump, the protective tube 12 shown in FIG. , 13, the water injection port 20 and a device for injecting water into the water injection port 20, which is not shown in FIG. 1, are unnecessary, and in the case of using the journal bearing of the present invention, a bearing member will be described later. Since it is possible to reduce the size of the lower submerged bearing 15, the lower submerged bearing 15 can also be made smaller, and the rib 17 'can be easily attached. Therefore, the rib 17 for supporting the lower submerged bearing 15 shown in FIG. 1 is unnecessary. The structure is extremely simple.

That is, as is clear from FIG. 4 and the description relating to FIG. 4, the journal bearing of the present invention can withstand an extremely high surface pressure load of 10 times or more that of the conventional product, so that the sliding area is made extremely small. Therefore, the submerged bearings 14 and 15 shown in FIG. 5 may be small.

FIG. 6 is an enlarged view of one side of the upper submerged bearing 14 in FIG. 5, but a sliding portion is formed by a sleeve 38 made of cemented carbide and a bearing 39 made of silicon nitride ceramics or silicon carbide ceramics.

The bearing 39 is fixed to the case 40 by shrink fit and fixed to the bearing support 16 side, and the sleeve 38 is fixed to the shaft 5'by a set screw (not shown).

The above is an example in which the present invention is applied to a submersible bearing of a vertical shaft pump, but the same action and effect are also exerted when applied to an oblique shaft pump.

Although the sleeve 38 is longer than the bearing 39 for mounting, it is of course possible to use the sleeve 38 having the same length as the bearing 39. Further, when seawater is handled by the pump shown in FIG. 5, it is preferable that the corrosion current generated between the shaft and the casing becomes extremely small or substantially no corrosion current flows.

When the journal bearing of the present invention is used as the submersible bearing, the shape thereof is cylindrical as shown in FIG. 6 together with the cemented carbide and silicon nitride or silicon carbide ceramics, and the cemented carbide is used as a shaft sleeve. Alternatively, silicon carbide ceramics may be used as the bearing. That is, as long as it has a cylindrical shape, a cemented carbide, silicon nitride, or silicon carbide ceramics can be easily formed, and can be manufactured at a lower cost than an underwater bearing having a complicated shape.

As described above, the journal bearing of the present invention is a journal bearing in which the rotating side member is made of cemented carbide and the fixed side member is made of silicon nitride or silicon carbide ceramics. That is, it has extremely stable sliding characteristics even when sliding in gas, and has even more excellent sliding characteristics under the condition of being lubricated with water. Even when it slides in slurry water composed of fine particles, it maintains its good sliding characteristics, so it is a sliding part that operates under conditions in which an unlubricated state and a lubricated state repeatedly appear. In particular, it is possible to provide a journal bearing for a pump and a pump using the journal bearing, which is extremely suitable for a sliding portion that operates in an abradable handling liquid.

In addition, since silicon nitride ceramics and silicon carbide ceramics have good insulating properties, if they are used as bearings that operate in a liquid with good electrical conductivity, they can block the corrosion current and protect the surrounding metal members. In addition, since it can withstand a high surface pressure load, the sliding part can be made small, and the life of the sliding part can be dramatically extended. It can be said that it is an excellent bearing.

[Brief description of drawings]

FIG. 1 is a schematic view of a conventional vertical shaft pump, FIG. 2 is a schematic view of the upper submerged bearing, FIG. 3 is a sectional view of a sliding test device, and FIG.
FIG. 5 is a diagram showing the coefficient of friction of the bearing, FIG. 5 is a schematic diagram of a vertical shaft pump using the bearing of the present invention, and FIG. 6 is a schematic diagram of the upper submerged bearing. 1 ... outer water level, 2 ... impeller, 3 ... drive motor, 5,
5 '... Axis, 9,10 ... Suspension pipe, 11 ... Discharge elbow, 12,
13 …… Protection tube, 14 …… Upper underwater bearing, 15 …… Lower underwater bearing, 17,17 ′ …… Rib, 18 …… Sleeve, 19 …… Rubber bearing, 20 …… Water inlet, 21 …… Hydraulic motor , 23 …… axis, 25,2
6 …… Test piece, 27 …… Bearing house, 28 …… Load cell, 3
3 …… Hose, 35 …… Test tank, 38 …… Cemented carbide sleeve, 39 …… Ceramics bearing

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Shikuo Koide 11-11 Haneda-Asahi-cho, Ota-ku, Tokyo Inside the EBARA CORPORATION (72) Inventor Shotaro Mizobuchi 11-11 Haneda-Asahi-cho, Ota-ku, Tokyo EBARA CORPORATION (56) Reference JP-A-55-93998 (JP, A) JP-A-54-120612 (JP, A) JP-A-55-109287 (JP, A) JP-A-58-160625 ( JP, A) JP 57-163198 (JP, A) JP 48-57034 (JP, A) Actual development 58-61920 (JP, U) Actual public 29-17308 (JP, Y1) 1977 October, published by Nikkan Kogyo Shimbun, Machine Design Vol. 21, No. 11, pages 109 to 112

Claims (2)

[Claims] 1. A pump device in which a pump shaft is passed through a passage for a liquid to be handled by a pump, which is exposed in a passage for a liquid to be handled,
Lubricated in the handling liquid and air in the flow path, the rotating side member is made of cemented carbide with a tungsten carbide (WC) content of 90% by weight or more, and the fixed side member is silicon nitride (Si ₃ N ₄ ) or silicon carbide. A journal bearing for a pump, characterized by being made of ceramics made of (SiC). 2. A rotary side member is made of tungsten carbide (W
C) A pump journal bearing made of a cemented carbide with a content of 90% by weight or more, and a stationary member made of ceramics made of silicon nitride (Si ₃ N ₄ ) or silicon carbide (SiC),
At least one pump shaft is provided on a pump shaft that rotates in the liquid to be handled and air, and a pump configured to pass the pump shaft into the flow path of the liquid to be handled of the pump.