JPS6142114B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a main bearing that supports the main shaft of a hydraulic machine, and more particularly to an oil-free submersible bearing water supply device in which the main bearing is lubricated with water.

Water-lubricated submerged bearings are the main bearings that support the main shafts of hydraulic machines, and these submerged bearings tend to be used in applications with relatively small radial loads, such as Kaplan water turbines. The types of underwater bearings are roughly divided into those that use lignum vitae exclusively for water lubrication, and ordinary white metal bearings that use grease as a lubricant. The former method not only causes significant wear but also expands due to the presence of moisture, resulting in poor dimensional accuracy and is not often used, so the latter method of grease lubrication is mostly used. However, in this grease lubrication method, it is customary to supply pressurized water to prevent river water containing earth and sand from entering the bearing, and most of the grease supplied by this pressure water flows out into the river. There was a problem with river pollution.

Therefore, recently, phenolic resin-based materials have been adopted as bearing materials to eliminate the need for lubrication. However, unlike the grease lubrication method, this method does not use any lubricant other than water, so fresh water with a higher pressure than the river water at the bottom of the bearing is supplied to the bearing, and river water containing earth and sand, etc. It is necessary to prevent intrusion and prevent damage and wear on the bearing sliding parts. However, this clean water must be clean water that does not contain hard foreign substances, such as tap water, ground water, spring water, etc., and disposing of this clean water causes problems such as increased operating costs. In addition, clean water can sometimes be obtained from river water, but not only is a filtration device required to purify the river water, but this filtration device requires a fine mesh, so it can be clogged with foreign substances. There was a problem that caused operational problems due to such factors, and the frequency of maintenance inspections increased.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an oil-free submersible bearing water supply device that circulates and reuses fresh water to ensure stable operation and minimizes the consumption of fresh water.

In order to achieve the above object, the present invention provides a main shaft sealing device in a hydraulic machine equipped with a main bearing with fresh water lubrication that supports the main shaft, and a main shaft water sealing device that is arranged below the main bearing and prevents the inflow of river water. An upper water tank placed in a position to obtain a hydrostatic pressure higher than the water pressure acting on the lower end of the water device, a lower water tank connected to this upper water tank and placed on the upper cover, and a fresh water supply source connected to the upper water tank. , an automatic fresh water replenishment device that maintains the water level of these water tanks at a constant level is connected to the lower water tank, and the discharge pressure is higher than the water pressure at the lower end of the main shaft water sealing device, and the discharge amount is greater than the required amount of lubricating water for the main bearing. a first fresh water supply system that is connected to the discharge side of the pump and supplies fresh water from the lower end of the main bearing and returns to the lower water tank from the upper end via a regulating valve; and this first fresh water supply system. It is equipped with a second fresh water supply system that branches from the inlet side of the system and returns excess water for main bearing lubrication to the lower water tank via the upper water tank, thereby stably and repeatedly supplying fresh water for main bearing lubrication. can be used.

An embodiment of the present invention will be described below with reference to FIG.

Reference numeral 1 denotes a water-lubricated main bearing that supports the main shaft, and a main shaft water sealing device 3 is arranged below the main bearing 1 to prevent river water from flowing in. This main shaft water sealing device and the lower end of the main bearing 1 form a lower pressure chamber 5, and an upper pressure chamber 4 containing pressure water that lubricates and cools the sliding surfaces of the main bearing 1 is located in the upper part of the main bearing 1.
It is formed by the upper end of and the packing 2. And, 6 is an upper water tank, and this upper water tank 6 is placed at a position where a hydrostatic pressure higher than the water pressure at the lower end of the main shaft water sealing device 3 can be obtained, for example, at a position higher than the highest water level on the inlet side flowing into the water turbine, A lower water tank 7 is arranged above the upper cover of the water turbine, and a pressure water tank chamber 8 formed by the main bearing 1 and the upper cover is arranged below the lower water tank 7 and on the outer peripheral side of the main bearing 1. A suction pipe 10 of a pump 9 that supplies lubricating water to the main bearing 1 is connected to the lower water tank 7 via a foot valve 21. This pump 9 is selected so as to obtain a discharge pressure higher than the head required to suck up fresh water from the lower water tank 7 to the upper water tank 6, and a discharge amount greater than the amount of water required to lubricate the main bearing 1. . The discharge pipe 11 of the pump 9 is connected to a first fresh water supply system connected to the pressure water tank chamber 8 via a water supply pipe 13, and a connecting pipe 1.
2, and a second fresh water supply system connected to the upper water tank 6 via the water tank 6. And pressure water tank chamber 8
is connected to the lower pressure chamber 5 of the main bearing 1 through the communication hole 20, and the upper pressure chamber 4 is connected to the lower water tank 7 through the regulating valve 17 provided in the drain pipe 16, forming a first water supply system. . Further, a second water supply system branched from the discharge pipe 11 is connected to a communication pipe 14 via a communication pipe 12 and an upper water tank 6.
is connected to the lower water tank 7 via a constant water level valve 15. A water supply main pipe 19 is connected to the upper water tank 6, and this water supply main pipe 19 has a constant water level valve 18 disposed in the pipe and is connected to a fresh water supply source.

Next, the effect will be explained. Prior to operation, each chamber is filled with a predetermined amount of fresh water. When the water turbine is in operation, the pump 9 is continuously operated, and fresh water from the lower water tank 7 is sucked by the pump 9 through the foot valve 21 and the suction pipe 10, pressurized, and supplied to the discharge pipe 11. The pressurized fresh water is sent from the discharge pipe 11 to the pressure water tank chamber 8 via the water supply pipe 13 which is the first fresh water supply system, and the surplus water is sent to the communication pipe 12 which is the second fresh water supply system.
The water is supplied to the upper water tank 6 via. Pressure water tank chamber 8
The pressurized fresh water supplied therein enters the lower pressure chamber 5 through the communication hole 20, lubricates and cools the sliding portion of the main bearing 1, and reaches the upper pressure chamber 4. On the other hand, since the fresh water pressure supplied to the lower pressure chamber 5 is set to a higher pressure than the outer circumference of the runner boss 22 located below the main bearing 1, some of the fresh water flows downward through the main shaft water sealing device 3. This prevents river water containing earth and sand from entering the main bearing 1. On the other hand, fresh water in the upper pressure chamber 4 is configured to flow back to the lower water tank 7 via a regulating valve 17 and a drain pipe 16. The regulating valve 17 arranged in the drain pipe 16 is connected to the main bearing 1.
The amount of lubricating water passing through is adjusted, and the opening degree is adjusted so that the fresh water pressure in the lower pressure chamber 5 is higher than the river water at the lower end of the main shaft water sealing device 3.

Further, since the discharge amount of the pump 9 is selected to be larger than the required amount of lubrication for the main bearing 1, excess water flows to the upper water tank via the connecting pipe 12. Excess water that has flowed into the upper water tank 6 is returned to the lower water tank 7 via the connecting pipe 14. A constant water level valve 15 is provided at the outlet end of the communication pipe 14 to prevent unnecessary flow from the upper water tank 6 to the lower water tank 7 and to keep the water level in the lower water tank 7 constant. In other words, the drain pipe 1
Since the amount of water returned to the lower water tank 7 is smaller than the amount of water returned to the lower water tank 7, the amount of water returned from the upper water tank 9 is equal to the decrease in the water level of the lower water tank. If this operation is repeated, the amount of water leaking from the pressure chamber 5 through the seal 3 will increase.
The total amount of water in the circulatory system will decrease. This decrease first appears as a drop in the water level in the upper water tank 6. Therefore, when the water level in the upper water tank 6 decreases, the constant water level valve 18 provided in the upper water tank 6 opens and the water supply main pipe 19 opens.
Replenish fresh water from the tank.

As explained above, according to this embodiment, the fresh water sucked up by the pump 9 from the lower water tank 7 is circulated to the lower water tank 7 again for reuse, and the amount of water flowing out from the main shaft water sealing device 3 to the river is transferred to the upper water tank. Since the water is automatically replenished from the main water supply pipe 19 provided at 9, the total amount of water can be kept constant at all times, allowing economical and stable summer rotation. In addition, since the pressure water tank chamber 8 is provided on the outer circumferential side of the main bearing 1, the heat generated by the sliding of the main bearing 1 can be cooled by hanging it on the outside, and the heated fresh water can be cooled by the river water flowing outside the water wheel upper cover. You can also do it. Furthermore, since the upper water tank 6 is installed in a position where a higher hydrostatic pressure can be obtained than the water pressure acting on the lower end of the main shaft water sealing device 3, the main shaft water sealing device can be connected to the lower pressure chamber 5 even in the event of a failure of the pump 9 or a loss of power. A higher fresh water pressure can be introduced than the lower end of the main bearing 1, and the main bearing 1 can be lubricated safely without the inflow of river water.

Next, other embodiments of the present invention will be described. The one shown in Figure 2 has multiple hydraulic machines with an upper water tank 6.
The other configurations are the same as those of the previous embodiment.

In this way, the bearing water supply device for each machine has exactly the same effect as the main shaft water sealing device, but the communication pipes 12 and 14 from multiple machines are connected to one upper water tank 6, and this upper water tank 6 will be shared by each machine. Surplus water is sent to the upper water tank 6 from a pump 9 operated for each machine, and if the water level in the lower water tank 7 of each machine falls, each constant water level valve 15 opens according to the water level of each lower water tank. ,
Water is sent from the shared upper water tank 6 to the lower water tank 7 via the communication pipe 14. Therefore, there is no imbalance in the water in the lower water tanks of each machine. Furthermore, even if the pump 9 of any or all of the machines breaks down, the stored water in the upper water tank 6 will be supplied by gravity to the pressure water tank 8 of the machine whose pump 9 is out of order. When the water level in the upper water tank 6 decreases due to this, the constant water level valve 18 opens and fresh water is supplied from the main water supply pipe 19. Therefore, the bearing water supply system of the machine where the pump has failed is the same as when the pump is operating. be able to perform its functions.

In this embodiment as well, there is no imbalance in the water level in the lower water tank 7 of each machine, and since one upper water tank 6 is shared by a plurality of machines, it is very economical.

As explained above, according to the present invention, there is no need to dispose of fresh water as in the past, and only the amount of water leaking from the main shaft water sealing device needs to be compensated, making it possible to significantly reduce the amount of fresh water used. In addition, the pressure regulating valve can easily maintain a predetermined pressure higher than the lower end of the main shaft water sealing device, and even when the pump fails, the same function as when the pump is in operation can be achieved.

[Brief explanation of the drawing]

Fig. 1 is a system diagram showing the entire oil-free submersible bearing water supply system according to an embodiment of the present invention, and Fig. 2 shows connecting pipes for water lubrication from multiple machines to one upper water tank. FIG. 3 is a system diagram showing another example. 1... Main bearing, 2... Packing, 3... Main shaft water sealing device, 4... Upper pressure chamber, 5... Lower pressure chamber,
6... Upper water tank, 7... Lower water tank, 8... Pressure water tank chamber, 9... Pump, 10... Suction pipe, 11...
Discharge pipe, 12... Connection pipe, 13... Water supply pipe, 14
...Communication pipe, 15...Constant water level valve, 16...Drain pipe, 17...Adjusting valve, 18...Constant water level valve, 19...
...Water supply pipe, 20...Communication hole, 21...Foot valve.

Claims (1)

[Claims] 1. In a hydraulic machine equipped with a fresh water lubricated main bearing that supports the main shaft and a main shaft water sealing device that is placed below the main bearing and prevents river water from flowing in, the water pressure that acts on the lower end of the main shaft water sealing device. An upper water tank placed in a position to obtain higher hydrostatic pressure, a lower water tank connected to this upper water tank and placed on the upper cover, and an upper water tank and a fresh water supply source are connected to keep the water level of these tanks constant. A pump that is connected to the lower water tank and has a discharge pressure higher than the water pressure at the lower end of the main shaft water sealing device and has a discharge volume greater than the required amount of lubricating water for the main bearing, and the discharge side of this pump. A first fresh water supply system connects to the main bearing and supplies fresh water from the lower end side of the main bearing and returns to the lower water tank from the upper end side via a regulating valve. An oil-free submersible bearing water supply system comprising: a second fresh water supply system that returns surplus water for lubrication to the lower water tank via the upper water tank.