JPS628689Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a shaft sealing device for powder, which is applied to powder such as lime and cement.

Normally, this type of shaft sealing device is widely used in powder transportation equipment such as screw conveyors and rotary valves, or in crushers, but conventional shaft sealing devices for powder only use mechanical seals. Therefore, when the shaft diameter is large, it is difficult to control the flatness of the rotating sliding surface, and the shaft vibration is very large.
Additionally, if the shaft of the machine is installed obliquely to the horizontal plane, vibrations and inertia due to the retainer's own weight will cause the surface to open, and once powder enters the rotating sliding surface, Powder becomes clogged, and the rotating and sliding parts are made of hard materials, which increases local surface pressure and causes abnormal wear, resulting in loss of shaft sealing function, or There were drawbacks such as the huge cost required for maintenance due to abnormal wear.

On the other hand, a structure has been proposed in which a felt shaft gasket is provided at the entrance of the rotating sliding surface to prevent powder from entering the rotating sliding surface, but this method does not allow powder to enter the rotating sliding surface. On the other hand, undesirable phenomena such as the sliding portion becoming clogged with powder occurred.

The present invention was developed to eliminate the above-mentioned defects, and its purpose is to form an air flow extending from the atmosphere side to the powder side, and to use this air flow to enter the rotating sliding surface. This prevents the powder by blowing it toward the powder side, prevents the lubricant for the bearing from leaking to the powder side through the seal, and prevents the powder from entering the rotating sliding surface. It is an object of the present invention to provide a shaft sealing device for powder which is suitable for preventing the above. In order to achieve the above object, the present invention provides a seal portion near the tip of the casing that seals between a fixed shaft and a casing that is rotatably supported on the fixed shaft, and the seal portion and the casing An inlet of the seal part communicating with the outer powder side is provided in contact with the fixed shaft, and an air flow passage communicating with the vicinity of the inlet of the seal part from the atmosphere side is provided in the fixed shaft, and an air flow path is provided in the fixed shaft, and the air flow passage communicates with the front end surface of the casing. A labyrinth ring that forms an air flow passage by a labyrinth mechanism that communicates with the seal inlet is fixed in between, and a labyrinth ring is fixed to the air side to prevent powder from entering the seal inlet through the air flow passage. This allows air to flow from the to the powder side.

Hereinafter, embodiments of the present invention will be specifically described based on the drawings shown in FIGS. 1 to 3.

Fig. 1 shows a powder shaft sealing device 1 according to the present invention applied to a crusher, and 2 is a cylindrical casing to which a roller (not shown) of the crusher is integrally attached. The mechanism is such that the powder is granulated as the pulverizer rotates, and the powder is transported by a large fan (not shown) while the pulverizer is granulated.

Reference numeral 3 denotes a crusher frame, and a fixed shaft 4 having one end facing the atmosphere side A is integrally attached to the crusher frame 3. A bearing 5 is interposed between the fixed shaft 4 and the casing 2 to support the casing 2 concentrically and rotatably with the fixed shaft 4.

The casing 2 has a first inward protrusion 6 at a distal end that extends vertically from the distal end toward the axis of the casing 2, and is spaced from the first inward protrusion 6 by a predetermined distance. It has a second inward protrusion 7 that is arranged in a parallel ring and located in front of the bearing 5 (on the left side in FIG. 1), and these first inward protrusion 6 and second inward protrusion A seal portion 8 is formed between the portion 7 and the portion 7 . A shaft hole is maintained at an appropriate interval between the first inward protrusion 6 and the outer circumferential surface of the fixed shaft 4, and this shaft hole allows the sealing portion 8 and the powder on the outside of the casing 2 to be removed. Body side B is in communication. That is, the shaft hole forms a seal portion entrance 8a that is in contact with the fixed shaft 4. Furthermore, a distance is maintained between the second inwardly protruding portion 7 and the outer circumferential surface of the fixed shaft 4 to allow the passage of lubricating oil therebetween.

The fixed shaft 4 is provided with an axial air flow hole 9 extending in the axial direction at its axial center, and the axial air flow hole 9 extends from one end of the fixed shaft 4 facing the atmospheric side A to It has a length sufficient to reach the inlet portion of the seal portion 8. In addition, at or near the end of the axial airflow hole 9, the axial airflow hole 9
and extends radially from the seal portion inlet 8a.
A radial air circulation hole 10 is formed that reaches the outer circumferential surface of the fixed shaft 4 below or slightly in front of the first inward protrusion 6 (towards the left in FIG. 1). In this embodiment, there is one radial air circulation hole 10, but if necessary, it may be formed into a number of radial air circulation holes communicating from the axial air circulation hole 9 toward the outer circumferential surface of the fixed shaft 4. It is also possible to have book radial air flow holes 10. A series of air flow passages 11 consisting of the axial air flow holes 9 and the radial air flow holes 10 communicate the seal portion inlet 8a with the atmosphere side A.
This allows air from the air to be supplied to the inlet of the seal portion 8.

A plurality of grooves 6a (three grooves in this embodiment) are formed in an annular shape on the front surface of the first inward protrusion 6. On the other hand, a bolt 13 is attached to the fixed shaft 4.
A labyrinth ring 12 is fixedly attached to the labyrinth ring 12, and a flange-like portion 14 protrudes from one side of the labyrinth ring 12. The rear end surface of this flange-like portion 14 is located opposite to the front surface of the first inward protrusion 6, and the rear end surface of this flange-like portion 14 has several grooves that can face the groove 6a. A protrusion 15 is provided in an annular shape. In other words, the groove 6a...
A labyrinth mechanism of several stages (three stages in this embodiment) is formed by the combination of the projections 15 and 15, and an air flow passage 16a through which the air flow meanderes in a zigzag pattern is formed within this labyrinth mechanism. In this way, the labyrinth mechanism 16 has several stages of zigzag-like meandering air flow passages 16a, so that air can spread over the entire surface where the powder is about to enter, and a uniform flow velocity can be obtained. Furthermore, this labyrinth mechanism 16 prevents the powder from entering the seal portion 8, and the pressure on the powder 20 side is maintained at a constant negative pressure of about 600 mmAq. Note that 17 is a sealing member such as an O-ring inserted between the labyrinth ring 12 and the outer peripheral surface of the fixed shaft 4, and 20 is a sealing member such as an O-ring on the powder side B, that is,
It shows powder accumulated on the outside of the casing 2, labyrinth ring 12, etc.

Next, the seal portion 8 will be explained.

That is, the seal portion 8 has an annular seal chamber 18 between the outer periphery of the fixed shaft 4 and the casing 2, and a seal ring 19 is accommodated in the seal chamber 18. This seal ring 19 has flange portions 19 on the outer periphery of both ends of the cylindrical portion 19a.
b, 19c are integrally formed, and the outer peripheral edges of the flanges 19b, 19c are
Annular rotating sliding surfaces 19d and 19e are provided in a protruding manner. Moreover, the cylindrical portion 19a of this seal ring 19
is fitted and fixed on the outer periphery of the fixed shaft 4 in the seal chamber 18, and the rotating sliding surface 1 of the flanges 19b, 19c
9d and 19e, respectively, the first inward protrusion 6
and between the atmosphere side seal chamber 18a, which is communicated with the atmosphere side A by sliding contact with the side surface of the second inward protrusion 7, the oil side seal chamber 18b, and the flanges 19b and 19c of the seal ring 19. The inner chamber 18c is divided into a sealed inner chamber 18c.

Therefore, when the pulverizer is operated now, the pressure on the powder side B decreases, and the powder side B is maintained at a constant negative pressure state. When the powder side B becomes negative pressure, this negative pressure eventually forms an air flow extending from the atmosphere side A to the powder side B as shown by the arrow in FIG. That is, the air entering the axial air circulation hole 9 of the fixed shaft 4 as shown by the arrow flows through the axial air circulation hole 9 and the radial air circulation hole 1.
0 sequentially to reach the sealing part inlet 8a, and then from this sealing part inlet 8a to the air flow passage 16a of the labyrinth mechanism 16 to reach the powder side B. Therefore, even if powder tries to enter from the powder side B through the airflow passage 16a of the labyrinth mechanism 16 to the seal portion 8 side, that is, to the rotating sliding surfaces 19d and 19e, it will not flow from the atmosphere side A to the powder side B. Air is flowing along the series of airflow passages 11, 16a, and the velocity of this airflow is increased by the labyrinth mechanism 16, so that the rotating sliding surfaces 19d, 19
The airflow automatically blows off the powder that is about to enter the rotary sliding surfaces 19d and 19e to the powder side B, and prevents the powder from entering the sealing portion 8, that is, the rotating sliding surfaces 19d and 19e. This prevents the powder from clogging 19e and increasing the local surface pressure, causing abnormal wear and impairing the shaft sealing performance.

In order to fully demonstrate the performance of the shaft sealing device 1 for powder, the mounting position of the labyrinth ring 12 of the labyrinth mechanism 16, that is, the gap between the air flow passages 16a is a major factor. It is shown in the figure and FIG. In other words, in Figure 2, the outlet flow rate is Q ₁ (m ³ /min) and the inlet flow rate is Q ₂
(m ³ /min), labyrinth gap C, powder side pressure P ₁
is 0.94Kgf/cm ² , atmospheric side pressure P ₂ is 1.0Kgf/cm ² , and seal pressure is Px, which is the graph showing the relationship between seal pressure Px and air flow rate Q in Figure 3. And V= where the wind speed in the labyrinth part is V=
Q/A Calculating the wind speed in the labyrinth section from the formula in ₁ : When C = 1.0 mm, V = 16.7 m/sec When C = 1.5 mm, V = 12.0 m/sec When C = 2.0 mm, V = 9.3 m/sec sec.

In addition, when the powder side B has a negative pressure as in the above embodiment, this negative pressure can be used to automatically create an air flow from the atmospheric side A to the powder side B. However, even if the powder side B is under positive pressure, the fixed shaft 4
A similar effect can be achieved by injecting air into the air flow passages of the.

As described above, the present invention provides an air flow passage that communicates from the atmosphere side to the powder side in order to prevent the intrusion of powder at the inlet portion of the seal portion of the fixed shaft. Since the air flow is formed to reach the powder side, the powder that tries to enter the rotating sliding surface is blown away to the powder side and blocked, and the lubricant for the bearing is transferred to the powder by the sealing part. It is possible to prevent powder from leaking to the side and prevent powder from entering the rotating sliding surface. Moreover, since the air flow path communicating from the seal part entrance to the powder side is formed in a zigzag flow path using a labyrinth mechanism, substances other than air are effectively prevented from passing through this air flow path. This prevents lubricant for bearings from entering the powder side. Furthermore, since the intrusion of powder is prevented between the labyrinth ring and the casing end face, which are non-contact, there is no need to control the flatness of the rotating sliding surface when the shaft diameter is large, and there is no need to control the flatness of the rotating sliding surface when the shaft diameter is large. It also prevents surface opening that occurs when installed, and furthermore, once powder enters the rotating sliding surface, it will clog, causing abnormal wear and damage to the shaft sealing function, resulting in huge maintenance costs. It has an extremely simple structure and has excellent effects that make it an excellent shaft sealing device that can be applied to various types of powder equipment.

[Brief explanation of the drawing]

Figures 1 and 2 show the first embodiment of the present invention; Figure 1 is a side sectional view thereof, Figure 2 is an explanatory diagram showing various numerical values in the labyrinth mechanism, and Figure 3 is a seal pressure FIG. 3 is an explanatory diagram showing the relationship between Px and air flow rate Q. FIG. 4...Fixed shaft, 8...Seal portion, 11...Air flow path, A...Atmosphere side, B...Powder side.

Claims (1)

[Scope of utility model registration request] A seal portion for sealing between a fixed shaft and a casing rotatably supported by the fixed shaft is provided near the tip of the casing, and a seal portion communicates with the powder side outside the casing. a labyrinth mechanism in which an inlet is provided in contact with the fixed shaft, an air flow passage is provided in the fixed shaft to communicate from the atmosphere side to the vicinity of the seal part inlet, and the air flow passage communicates with the seal part inlet between the front end surface of the casing; A labyrinth ring forming an air flow passage is fixedly attached to the labyrinth ring, and air flows from the atmosphere side to the powder side through this air flow passage to prevent powder from entering the sealing part inlet. A shaft sealing device for powder.