JPH061438A - Pressurizing supply device for powder - Google Patents

Abstract

PURPOSE:To shorten an inter-shaft distance so as to provide structural strength of a pressuring supply device against vibration due to nonuniform distribution of powder by decreasing the number of seals between bearings for supporting a rotor shaft. CONSTITUTION:High pressure oil feeders 13, 14 filled with high pressure oil are disposed, with a rotor 2 which has a radial powder passage extending from the central area toward the peripheral edge area and rotates inside a housing 1, being sandwiched between two bearings 10, 11 for supporting a rotor shaft 7. An introduction part for supplying control gas 9 to a passage disposed in the rotor shaft 7 is disposed in a part located outside the bearing 10 and having the same center of rotation as that of the rotor shaft 7 and a diameter smaller than that of the rotor shaft 7. By this arrangement, the seal constitution taking the rotor between two bearings 10, 11 as the center becomes symmetrical so as to decrease the number of seals arranged between bearings. Furthermore, as the introduction part for the control gas 9 is disposed outside the bearing 10, the distance between the bearings can be further shortened so as to provide structural strength against shaft vibration due to the mass unbalance of the rotor 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powder pressurizing supply device used for a fuel supply system of a pressurized fluidized bed boiler, and can also be applied to a fuel supply device of a coal gasification furnace.

[0002]

2. Description of the Related Art FIG. 4 shows an example of a conventional powder pressure supply device. This powder pressurizing and supplying device has a rotor 2 having a radial passage extending from a central portion toward a peripheral portion and rotating in a housing 1. In the rotor 2, powder 3 and powder feeding pipe 4 are provided together with a carrier gas. Is supplied via. The rotor 2 is fixed to a rotor shaft 7 which is rotatably supported so as to rotate across a high pressure gas portion and a low pressure gas portion in the housing 1, and a control gas 9 for controlling the amount of powder discharged from the rotor 2 is further fixed. It is supplied through a passage 8 provided in the rotor shaft 7.

The operation principle of this conventional powder pressurizing and feeding apparatus will be briefly described. An attempt is made to feed powder to a radial powder passage extending from a central portion to a peripheral portion provided in a rotor 2 rotating in a housing 1. The powder 3 is supplied and filled by a powder supply pipe 4 whose tip is inserted into the rotor 2.
The outer peripheral side of the powder passage communicates with the high-pressure space, and the inner peripheral side communicates with the low-pressure space via the return line 5. Therefore, in the powder passage, the gas tries to flow from the outer peripheral side to the inner peripheral side of the powder passage opposite to the direction in which the powder is supplied. Here, when the rotor 2 is rotated at a high speed, the powder 3 inside the passage receives a force toward the outside due to the centrifugal force, and the inside of the passage is filled without any gap. Then, the flow of gas from the outside to the inside can be reduced, and the powder can be sent to the outside against this flow. At this time, the amount of powder to be discharged is controlled by appropriately controlling the powder discharge amount control gas 9 through the high pressure gas supply pipe 6 and the passage 8 provided in the rotor shaft 7 in a valve attached to the outermost periphery of the powder passage. Done by feeding.

Conventionally, the following sealing system has been applied to such a powder pressure supply device. That is, between the two bearings 10 and 11 that support the rotor shaft 7 with the rotor 2 interposed therebetween, three high-pressure lubrication portions filled with high-pressure oil by the high-pressure lubrication oil 12, 13 and 14 are provided. Of these, the two high-pressure oil supply portions on the bearing 10 side are both sealed by setting the powder discharge amount control gas 9 on the high pressure side, and the powder purge gas 15 and the gas in the low pressure bearing space 16 on the low pressure side, respectively. The high pressure refueling portion on the side is for sealing the powder purge gas 17 on the high pressure side and the low pressure bearing space 18 on the low pressure side for sealing between them.
From the side, mechanical seal 19, lip seals 20, 2
1, mechanical seal 22, labyrinth seal 23, 2
4, a lip seal 25 and a mechanical seal 26 are provided. Such a sealing system is shown conceptually in FIG. In FIG. 5, reference symbol M is a mechanical seal, Lp is a lip seal, and Lb is a labyrinth seal.

[0005]

By the way, in the conventional powder pressurizing and supplying apparatus, the portion for supplying the control gas 9 is provided between the two bearings 10 and 11 which support the rotor shaft 7 with the rotor 2 interposed therebetween. Therefore, the number of seals between the bearings is increased, and the labyrinth seals 23 and 24, the lip seal 20,
21 and 25 and the mechanical seals 19, 22, and 26 are combined into eight.

Further, this device has the fate that the distribution of the powder in the internal powder passage is not always uniform, and therefore the imbalance in that the center of mass of the rotor 2 does not coincide with the center of rotation. Inevitable. In order to secure sufficient rigidity against imbalance and to operate the device with low vibration, it is necessary to reduce the distance between the bearings as much as possible. Therefore, in the conventional example, instead of a mechanical seal having a large axial length of the seal, a lip seal having a small axial length of the seal is used, and a part of the oil drain line is used to ensure proper use conditions of the lip seal. Is made to communicate with the low pressure side so that the pressure difference before and after sealing is limited to the head difference of the fluid.

[0007] However, although a device which can withstand practical use has been obtained by such a device, the following problems remain. That is, (1) It is desired to further shorten the bearing spacing in order to suppress the vibration further. (2) From the viewpoint of the durability of the seal, it is preferable to use a mechanical seal instead of the lip seal, but in that case, a large bearing gap is required. (3) In order to increase the rigidity of the shaft, it is desirable to make the shaft diameter as large as possible, but if this is done, the peripheral speed of the seal will increase and the risk of burnout of the seal will increase. (4) Since the pressure of the control gas fluctuates in a pulsed manner, it is difficult to keep the differential pressure before and after the lip seal constant, and there is a risk of burning the lip seal due to an excessive pressure difference. In addition, if it burns out, replacement of the seal at this portion requires disassembly of the entire device, which requires a long recovery time.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a powder pressurizing and feeding device which shortens the distance between bearings and is resistant to vibrations due to the fact that the center of mass does not coincide with the center of rotation. And

[0009]

To solve the above problems, according to the present invention, there is provided a rotor having a powder passage in a radial direction from a central portion to a peripheral portion, which rotates in a housing, and a rotor fixed to the rotor. Powder having a rotor shaft that rotates over a high-pressure gas portion and a low-pressure gas portion inside and outside the housing, and a passage that is provided on the rotor shaft and is supplied with a control gas that controls the amount of powder discharged from the rotor In the pressure supply device, a high-pressure oil supply portion filled with high-pressure oil is provided between two bearings that support the rotor shaft with the rotor interposed therebetween, and the control gas is supplied to a passage provided in the rotor shaft. There is provided a powder pressurizing and feeding device, characterized in that an introduction portion to be fed is arranged in a reduced diameter portion connected to the rotor shaft outside the bearing.

[0010]

According to the above-mentioned means, the seal structure centering around the rotor between the two bearings is symmetrical, the number of seals between the bearings is reduced, and the control gas introduction portion is arranged outside the bearings. As a result, the distance between the bearings can be further shortened, and the bearing can be made stronger against shaft vibration due to mass imbalance of the rotor.

[0011]

FIG. 1 is a conceptual diagram of a seal system of a powder pressurizing and feeding apparatus according to a first embodiment of the present invention. In the figure, the same parts as those shown in FIG. It is attached.

In FIG. 1, labyrinth seals 27 and 28 are used between a high pressure portion to which powder is supplied and a purge chamber having a higher pressure than that, and a mechanical portion is provided between the purge chamber and the high pressure oiling portion. The seals 29 and 30 further include a mechanical seal 3 between the high pressure oil supply portion and the low pressure portion of the bearing portion.
1, 32 are used respectively. Then, the control gas 9 passes through the passage 8 provided at the center of the rotor shaft 7 and the rotor 2
The bearings sandwiching the bearings, in the illustrated example, are guided to the outside of the bearing 10, and the four mechanical seals 33, 3 are provided in the reduced diameter portion of the rotor shaft 7.
A portion for introducing the control gas 9 consisting of 4, 35, 36 is provided. These mechanical seals 33, 34, 35,
36 is provided in the gas box 37.

To explain the operation, the high-pressure portion to which the powder 3 is supplied is adjacent to the portion for introducing the powder purge gas 15, 17 with the labyrinth seals 27, 28 provided between the bearings sandwiched therebetween. , This powder purge gas 15,1
Since the pressure of 7 is higher than that of the supply destination, the seal portion leaks from the purge chamber to the high pressure chamber, so that gas and powder in the high pressure portion do not enter the purge chamber.

On the other hand, the purge chamber is separated from the high pressure oil chamber by a seal, and the pressure of the oil is higher than the pressure of the purge chamber. It won't leak.

The control gas 9 is guided to the outside of the bearing 10 through a passage 8 provided in the rotor shaft 7, and is in contact with the normal pressure portion outside the bearing 10 via high pressure oil. That is, the control gas 9 is sealed outside the bearing 10 sandwiching the rotor, and the oil used as the buffer fluid prevents the gas in the high pressure portion from leaking to the low pressure portion between the bearings. Similarly, in the introduction portion of the control gas 9, the oil used as the buffer fluid prevents the control gas from leaking to the normal pressure portion.

Since the portion for introducing the control gas 9 at this time is provided outside the bearing, even if the diameter is made small, the high shaft required for shaft vibration caused by the imbalance of the powder is required. There is no loss of rigidity. Therefore, the peripheral speed of the seal portion can be reduced by designing the diameter of this portion to be small.

Further, except that labyrinth seals 27 and 28 are used in the portions which may come into direct contact with the powder, mechanical seals are used, and therefore long-term use is possible as compared with the case where a conventional lip seal is used. The reliability when doing is high.

FIG. 2 is a conceptual diagram of a seal system of a powder pressure supply device according to a second embodiment of the present invention. The difference from the first embodiment is that the introduction portion of the control gas 9 is provided in the rotor shaft 7 in the first embodiment, whereas it is provided in the shaft 38 different from the rotor shaft 7 in the present embodiment. The flexible gas hose 39 connects the control gas 9 passages of the two shafts 7 and 38. The shaft 38 is supported by two bearings 40 and 41, and the rotor shaft 7 and the shaft 38 are connected by a coupling 42. Although only one flexible hose 39 is used in the conceptual diagram, two flexible hoses 39 are used to balance the center of gravity.
It is desirable to use more than one and arrange symmetrically around the center of the shaft 37. Since the flexible hose 39 receives a centrifugal force due to rotation, a cover (not shown) is attached to the outside so as to serve as a guide.

In this structure, since the shaft for introducing the control gas 9 is separate from the rotor shaft 7, it is possible to make a large difference in diameter from the rotor shaft 7, so that the mechanical seal can be made small and the seal at this portion can be made smaller. When damaged, the shaft and the seal portion can be collectively replaced as an assembly, which has the advantage that the downtime can be shortened.

FIG. 3 is a conceptual diagram of a seal system of a powder pressure supply device according to a third embodiment of the present invention. The difference from the first embodiment is that the control gas 9 is supplied from the peripheral surface portion of the shaft in the first embodiment, whereas it is supplied from the end surface of the shaft in the present embodiment.

The number of seals can be reduced by supplying from the end surface of the shaft. In this structure, the thrust of the axial direction is generated by the pressure of the high-pressure control gas applied to the shaft end surface, so it is desirable to make the diameter of the seal portion as small as possible.

[0022]

According to the present invention, by reducing the number of seals between the bearings that support the rotor shaft, the distance between the shafts can be shortened, and the vibrations due to the non-uniform distribution of powder can be strengthened.

Further, since the diameter of the seal portion can be reduced, the peripheral speed of the seal can be reduced and the risk of burnout can be reduced. Further, particularly in the case of a mechanical seal, the cost can be reduced by reducing the size.

Further, since the control gas sealing portion, which is the most severe condition for the pulse-like pressure fluctuation, is located outside the bearing, replacement in case of damage is easy and downtime can be reduced. it can.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a seal system of a powder pressure supply device according to a first embodiment of the present invention.

FIG. 2 is a conceptual diagram of a seal system of a powder pressure supply device according to a second embodiment of the present invention.

FIG. 3 is a conceptual diagram of a seal system of a powder pressure supply device according to a third embodiment of the present invention.

FIG. 4 is a vertical sectional view illustrating a conventional powder pressure supply device.

FIG. 5 is a conceptual diagram of a seal system of a conventional powder pressure supply device.

[Explanation of symbols]

 2 rotor 3 powder 7 rotor shaft 8 passage 9 control gas 10 bearing 11 bearing 13 high pressure oil supply 14 high pressure oil supply 15 powder purge gas 37 gas box 39 flexible hose

Claims (1)

[Claims] 1. A rotor having a powder passage in a radial direction extending from a central portion to a peripheral portion and rotating in a housing, and a rotor fixed to the rotor and rotating across a high pressure gas portion and a low pressure gas portion inside and outside the housing. In the powder pressurizing and supplying device having a rotor shaft for rotating and a passage, which is provided on the rotor shaft and to which control gas for controlling the amount of powder discharged from the rotor is supplied, Are provided between two bearings that support the rotor shaft with the rotor sandwiched therebetween, and an introduction portion that supplies the control gas to a passage provided in the rotor shaft is connected to the rotor shaft outside the bearing. A powder pressurizing and feeding device characterized by being arranged in a reduced diameter portion.