JP4280217B2 - mechanical seal - Google Patents

Description

  The present invention relates to a mechanical seal of a rotating shaft portion, and more particularly to a mechanical seal used in a kneading apparatus or the like.

  A kneading apparatus 50 that uses a mechanical seal of a shaft portion that penetrates a casing side wall and protrudes out of the casing, as shown in FIGS. 6 to 7, is a kneading tank (hereinafter, referred to as “chamber 51”) that contains a kneaded material. And a rotor drive shaft 54 that penetrates the side wall 52 of the chamber 51 at both ends, is connected to the rotor drive shaft 54, and kneads the kneaded material in the chamber 51, and a pressure lid 55. When kneading the kneaded material, the kneaded material is put into the chamber 51 by an appropriate means with the pressure lid 55 opened upward, and the pressure lid 55 is lowered and connected to the rotor drive shaft 54. The kneaded material is kneaded by rotating the rotor R by driving means such as a motor.

  The mechanical seal 60 is provided with a packing presser 62 having a mechanical seal packing 61 disposed on the entire periphery of the packing guide 66 attached to a receiving member 53 provided in the vicinity of the through hole of the rotor drive shaft 54 of the side wall 52 via a bolt 63. And fix.

  Then, the nut 64 is tightened and pressed by the spring 65, and the end surface of the mechanical seal packing 61 is worn on the flange s end surface of the rotor R while the outer peripheral surface of the mechanical seal packing 61 is brought into sliding contact with the inner peripheral surface of the packing guide 66. By pressing against the plate w (packing receiving member), the kneaded material kneaded in the chamber 51 is prevented from leaking outside.

By the way, during kneading, the rotor drive shaft is deflected by the load, and the flange part is shaken.However, in the conventional mechanical seal, since the mechanical seal packing is pressed against the end surface of the rotor flange part, sealing is performed. It is difficult to press the sliding surface of the packing in parallel with the end face of the rotor collar following this vibration, and the kneaded material tends to bite into the sliding surface.
This problem is dealt with by increasing the surface pressure acting on the sliding surface. However, the wear of the packing becomes intense, and wear powder is easily generated, and the life of the packing is also reduced.
Then, the sliding surface may remain open due to the biting material, and the material may leak continuously, and the material biting into the sliding surface may return to the chamber and become contaminated. It was.
In the kneading operation, if the kneaded material that has entered the mechanical seal part returns to the chamber again, there may be a quality problem as contamination, and the kneaded material that has entered once is discharged outside without returning to the chamber. A seal structure is required.

  In view of such problems, the present invention can maintain a state where the sliding surfaces are closed even when the rotor drive shaft is bent, and lowers the surface pressure required for the seal to reduce the life of the packing. It aims at providing the mechanical seal which can improve.

To achieve the above object, in the mechanical seal of the shaft portion which projects outside the casing through the casing side wall, while disposed a ring-shaped mechanical seal packing to the sliding surface of the outer end surface on the outside of the casing side walls, the A ring-shaped packing receiving member with a sliding surface slidably contacting the mechanical seal packing on the inner end surface is urged toward the mechanical seal packing side by the urging means, the two sliding surfaces are brought into contact with each other, and the inner peripheral portion becomes the shaft portion. The mechanical seal packing is disposed so as to rotate integrally with the shaft portion in contact with the inner surface of the mechanical seal packing, the inner portion having a minute gap with the shaft portion, the inner end surface of the packing receiving member, and the shaft. And an outer portion that constitutes an annular pocket serving as a reservoir for material leaking from the minute gap .

  Further, in this case, a push-back member that is elastically supported by a spring on the outer end surface of the packing receiving member so as to face the packing receiving member and pushes back the packing receiving member to be separated from the mechanical seal packing by the reaction force of the spring. Can be provided on the casing side.

  Further, in this case, the push-back member is fixed to the tip of the yoke, the intermediate portion of the yoke is supported by a fulcrum erected from the bearing portion, and a spring is provided between the base of the yoke and the casing side wall. Can be arranged.

  Further, the push-back member can be elastically supported by a preloaded spring.

  Furthermore, the contact member can be configured to contact the packing receiving member at a position offset with respect to the shaft axis.

According to the mechanical seal of the present invention, the mechanical seal of the shaft portion which projects outside the casing through the casing side wall, while disposed a ring-shaped mechanical seal packing to the sliding surface of the outer end surface on the outside of the casing side wall The ring-shaped packing receiving member having a sliding surface that is in sliding contact with the mechanical seal packing on the inner end surface is urged toward the mechanical seal packing side by the urging means, the two sliding surfaces are butted against each other, and the inner peripheral portion is the shaft. The mechanical seal packing is arranged so as to rotate integrally with the shaft portion in contact with the shaft portion, the inner peripheral surface where the gap with the shaft portion is a minute gap, the inner end surface of the packing receiving member, from becoming formed by the outer portion constituting the annular pocket as a reservoir portion of the material leaking from the minute gap by said shaft portion, the sliding surface of the packing receiving member Rotating together with the shaft while applying the required surface pressure to the seal by the biasing means and being pressed against the sliding surface of the mechanical seal packing, the sliding surfaces of the mechanical seal packing and the packing receiving member are not affected by the deflection of the shaft. In addition to being able to prevent or effectively suppress leakage of material from between the sliding surfaces, the contact pressure required for sealing can be lowered to improve the life of the packing. be able to.
In particular, the inner peripheral surface of the mechanical seal packing is an annular portion that serves as a reservoir for material leaking from the minute gap by the inner portion where the gap with the shaft portion is at a minute interval, and the inner end surface of the packing receiving member and the shaft portion. By forming with the outer part which comprises a pocket, the backflow to the inside of the chamber of the kneaded material which entered the shaft seal part does not arise, and contamination can be prevented.
When changing the material, open the sliding surface of the mechanical seal packing and rotate the shaft before kneading the next material, so that the previous kneaded material remaining between the shaft and the mechanical seal packing is removed. It can be discharged in a twisted state. Then, the contamination of different materials can be prevented by closing the sliding surface and kneading the next material.

  Further, a push-back member is provided on the casing side on the outer end surface of the packing receiving member, which is elastically supported by a spring so as to face the packing receiving member, and pushes back the packing receiving member to be separated from the mechanical seal packing by the reaction force of the spring. In some cases, the packing receiving member to be separated from the mechanical seal packing is pushed back and maintained between the sliding surfaces in a closed state, and leakage of the material from between the sliding surfaces can be prevented or effectively suppressed.

  In this case, the push-back member is elastically supported by a pre-loaded spring, so that the reaction force of the spring is strengthened, and the push-back member is placed at a slight interval so as to contact the packing receiving member only when the material is caught. Accordingly, wear of the push-back member and the packing receiving member can be prevented without causing unnecessary friction.

  In addition, the abutment member is fixed to the tip of the yoke, and the intermediate portion of the yoke is supported by a fulcrum erected from the bearing portion, and a spring is disposed between the base of the yoke and the casing side wall. With this configuration, the packing receiving member separated from the mechanical seal packing can be pushed back by utilizing the action of the lever.

  Further, when the contact member is configured to contact the packing receiving member at a position offset with respect to the shaft core, the material to be discharged by being twisted from between the sliding surfaces is crushed. Rather than cutting, it can be cut so that it is sheared diagonally, dropped and discharged to the outside.

  Hereinafter, embodiments of a mechanical seal of the present invention will be described with reference to the drawings.

1 to 4 show an embodiment of the mechanical seal of the present invention.
In addition, in the kneading apparatus 10, about the structure similar to the content demonstrated by the prior art example, the description is abbreviate | omitted by writing the same code | symbol.

The mechanical seal 1 of the present embodiment is a mechanical seal of a rotor drive shaft 54 that penetrates the casing side wall 52 of the kneading apparatus 10 and protrudes out of the casing, and is roughly divided into a mechanical seal packing 2 and a packing receiving member 3. And a push-back member 4.
Hereinafter, description will be made sequentially.

The mechanical seal packing 2 is a ring-shaped member having the outer end surface 21 on the bearing portion 56 side as a sliding surface 21A. The mechanical seal packing 2 is fitted on a large-diameter portion 57 formed on the rotor drive shaft 54, and is convex on the outer peripheral surface. The part 25 is fixed to the outside of the casing side wall 52 by the fixing ring 22 so as to press down.
The inner peripheral surface of the mechanical seal packing 2 is configured such that the gap between the chamber 51 side and the large-diameter portion 57 is reduced as much as possible, and the outer-end surface 21 side has a constant gap with the large-diameter portion 57. The outer part 23 which comprises the annular pocket 23a which has is formed. The gap between the large diameter portion 57 and the inner portion 24 cannot be eliminated due to its structure, and after the kneading operation is started, the kneaded material leaks from the minute gap between the large diameter portion 57 and the inner portion 24. To do. However, the annular pocket 23a formed on the outer end face 21 side becomes a pooled portion of the leaked kneaded material, and the material once leaked from the chamber 51 is effectively prevented from flowing back into the chamber 5.

The packing receiving member 3 is made of a ring having an inner end surface 31 on the chamber 51 side as a sliding surface 31A, and is in contact with the rotor drive shaft 54 with an O-ring 32 interposed in the inner peripheral portion. The taper portion 57A of the large diameter portion 57 is externally fitted.
This packing receiving member 3 that rotates together with the rotor drive shaft 54 has an alignment property by a taper portion 57A of the rotor drive shaft 54 and an urging means 35 described later, and the sliding surface 31A and the slide of the mechanical seal packing 2 are aligned. The moving surface 21A is configured to come into contact with the outer periphery of the large-diameter portion 57 of the rotor drive shaft 54. Therefore, the moving surface 21A can always be in constant contact regardless of the deflection of the rotor drive shaft 54. It is not necessary to increase the pressure, and the life of the packing can be maintained for a long time.
The outer end surface 33 on the bearing portion 56 side of the packing receiving member 3 is formed as a flange portion 34, and four locations on the inner peripheral portion of the flange portion 34 are moved to the mechanical seal packing 2 side by biasing means 35 formed of a spring or the like. It is pressed.
The urging means 35 is interposed in a bolt 36 that passes through the flange portion 34 with play. The urging means 35 urges the packing receiving member 3 toward the mechanical seal packing 2 side by pressing the flange portion 34 from the outside. A gap is also formed between the inner peripheral portion of the portion 34 and the outer peripheral portion of the rotor drive shaft 54 so that the packing receiving member 3 can tilt.
The bolt 36 is screwed into the large diameter portion 57 of the rotor drive shaft 54, whereby the packing receiving member 3 rotates integrally with the rotor drive shaft 54.

The push-back member 4 is provided with an abutting member 40 so as to oppose two outer peripheral portions of the flange portion 34 of the packing receiving member 3.
The two abutting members 40 are respectively fixed to the tip end portion of the Y-shaped yoke 42, support the intermediate portion of the yoke 42 with a fulcrum 43 erected from the bearing portion 56, and the base portion of the yoke 42. By disposing the pre-loaded spring 41 between the casing side wall 52 and the packing receiving member 3 being separated from the mechanical seal packing 2, the spring 41 is pushed back by the reaction force of the spring 41. The base portion of the yoke 42 is slidably connected to shaft portions 42A projecting from both ends of the block 42B.
The contact portion of the contact member 40 with the flange portion 34 may be contacted at two locations in the diameter direction of the flange portion 34, but the position offset by a distance a below the axis of the rotor drive shaft 54 as shown in the figure. It is said. At this time, the offset direction is convenient for post-processing when the material leaked by twisting from the sliding surfaces 21A and 31A is cut off, and it is convenient for post-processing, and the fulcrum 43 and the spring serving as the action point Considering the distance up to 41, it is preferable to set the lower side. In this way, the contact portion with the flange portion 34 of the contact member 40 is set to a position offset by a distance a from the shaft center, thereby crushing the material that is twisted from the sliding surfaces 21A and 31A and leaks out. Instead of cutting in such a way, it can be cut and sheared from an oblique direction and discharged to the outside.
The spring 41 is inserted into a bolt 44 screwed into the casing side wall 52 and is in a pre-compressed state in which the spring 41 is fixed by being bent by a lock nut 45 via a block 42B. The sliding surfaces 21A, 31A Only when the material is bitten and the packing receiving member 3 is separated from the mechanical seal packing 2 and presses the contact member 40, a strong reaction force is applied with a quick response.
In this way, by elastically supporting the contact member 40 with the pre-loaded spring 41, the reaction force of the spring 41 is increased, and only when the material is caught in the sliding surfaces 21A and 31A, the contact is made with the packing receiving member 3. Thus, the abutting member 40 can be disposed with a very small interval, thereby preventing wear of the abutting member 40 and the packing receiving member 3 without causing unnecessary friction.

Further, the push-back member 4 can be arranged as shown in FIG. 5 without using the yoke 42 described above.
In the push-back member 4A shown in FIG. 5, a bolt 44A is erected from the bearing portion 56 toward the packing receiving member 3, and the contact member 40A is slidably inserted into the bolt 44A. Is elastically supported by the preloaded spring 41A so as to be urged toward the packing receiving member 3 side.
In this case, it is preferable to provide a plurality of push-back members 4A as in the first embodiment, and the spring 41A that elastically supports the contact member 40A can be a spring that does not preload as long as the spring force is strong. .
Further, as shown in FIG. 3, the yoke 42 is tilted so as to retract the abutting member 40 by tightening the lock nut 45, or the support bolt of the fulcrum 43 is retracted and the lock nut 37 of the bolt 36 is loosened. Thus, the packing receiving member 3 can be moved backward, whereby the sliding surface 21A of the mechanical seal packing 2 can be opened.
As described above, when the material is changed, the sliding surface 21A of the mechanical seal packing 2 is opened and the rotor drive shaft 54 is rotated before the next material is kneaded, thereby rotating the rotor drive shaft 54 and the mechanical seal packing 2 between them. It is possible to discharge the kneaded material before remaining in the twisted state. Thereafter, the sliding surfaces 21A and 31A are closed and the next material is kneaded to prevent contamination of different materials.

Thus, in the mechanical seal 1 of this embodiment, the ring-shaped mechanical seal packing 2 having the outer end surface 21 as the sliding surface 21A in the shaft-side mechanical seal that penetrates the casing side wall 52 and projects out of the casing 52 is provided. The ring-shaped packing receiving member 3 provided with the sliding surface 31A in sliding contact with the mechanical seal packing 2 on the inner end surface 31 is urged toward the mechanical seal packing 2 side so that both sliding surfaces are brought into contact with each other. Therefore, regardless of the deflection of the rotor drive shaft 54, the mechanical seal packing 2 and the sliding surfaces 21A and 31A of the packing receiving member 3 can always be in constant contact with each other. As a result, the surface pressure required for the seal can be lowered and the life of the packing can be improved.
A push-back member 4 that is elastically supported by a spring 41 so as to face the outer end surface 33 of the packing receiving member 3 and pushes back the packing receiving member 3 separated from the mechanical seal packing 2 by the reaction force of the spring 41 is provided on the casing side. Therefore, even if the kneading material is caught in the packing sliding surface, the push-back member 4 can be quickly pushed back by the strong reaction force of the spring 41 on the packing receiving member 3 that is going to separate by this biting. Leakage of the kneaded material from the sliding surfaces 21A and 31A can be prevented or effectively suppressed by maintaining the sliding surfaces 21A and 31A in a closed state.

In this case, the abutting member 40 is elastically supported by the pre-loaded spring 41, so that the reaction force of the spring 41 is strengthened, and a small interval is provided so as to contact the packing receiving member 3 only when the material is caught. The abutting member 40 can be disposed, and thereby the wear of the abutting member 40 and the packing receiving member 3 can be prevented without causing unnecessary friction.
Further, the abutting member 40 of the push-back member 4 is fixed to the tip end portion of the yoke 42, the intermediate portion of the yoke 42 is supported by a fulcrum erected from the bearing portion 56, and the base portion of the yoke 42 and the casing side wall 52 By adopting a configuration in which the spring 41 is disposed between them, the packing receiving member 3 separated from the mechanical seal packing 2 can be pushed back by utilizing the action of the lever.
Then, the packing receiving member 3 was retracted, and the sliding surface of the mechanical seal packing 2 was opened, so that the rotor driving shaft 54 was rotated and twisted in the shape of the remaining part between the rotor driving shaft 54 and the mechanical seal packing 2. The kneaded material can be discharged from the annular pocket 23a.

  As described above, the mechanical seal of the present invention has been described based on the embodiments thereof, but the present invention is not limited to the configuration described in the above embodiments, and for example, an open type kneading apparatus that does not use a pressure lid. The configuration can be changed as appropriate without departing from the spirit of the invention.

  The mechanical seal of the present invention can maintain or prevent the kneaded material from leaking between the sliding surfaces by keeping the sliding surfaces closed even when the rotor shaft is bent, and is necessary for the seal. Lower the surface pressure and improve the life of the packing. In addition, the leaking material that is about to pass through the mechanical seal packing is twisted into the shape of the shaft under the action of the inner peripheral surface of the fixed mechanical seal packing and the rotating shaft, making it easy to clean the mechanical seal packing when changing the material. In addition, since the material leaking from the mechanical seal packing does not flow back into the chamber, contamination can be prevented. Further, by providing a push-back member, the twisted diameter of the material that leaks from the sliding surface can be gradually reduced, and further, the contact receiving member is offset to make the packing receiving member in an inclined posture. Since it can be rotated, it has a number of characteristics that the material that leaks in a twisted shape can be cut and dropped and discharged, so it can be suitably used, for example, as a mechanical seal for a kneading apparatus .

It is sectional drawing which shows the kneading apparatus using one Example of the mechanical seal of this invention. It is sectional drawing which shows the mechanical seal of the Example. It is sectional drawing which shows the state which released the sliding surface of the mechanical seal. It is a partial expanded sectional view of the mechanical seal of this invention. The mechanical seal is shown, (a) is a plan view thereof, and (b) is a front view thereof. It is sectional drawing which shows the other Example of the mechanical seal of this invention. It is sectional drawing which shows the principal part of the conventional mechanical seal. It is front sectional drawing of a kneading apparatus.

DESCRIPTION OF SYMBOLS 1 Mechanical seal 2 Mechanical seal packing 21 Outer end surface 21A Sliding surface 22 Fixing ring 23 Outer part 23a Annular pocket 24 Inner part 3 Packing receiving member 31 Inner end surface 31A Sliding surface 32 O-ring 33 Outer end surface (bearing part side)
34 Flange portion 35 Energizing means 36 Bolt 37 Lock nut 4 Push-back member 40 Contact member 41 Spring 42 Yoke 43 Support point 44 Bolt 45 Lock nut 52 Casing side wall 54 Rotor drive shaft 56 Bearing portion 57 Large diameter portion

Claims (5)

In the mechanical seal of the shaft portion that penetrates the casing side wall and protrudes out of the casing, a ring-shaped mechanical seal packing having an outer end surface as a sliding surface is disposed outside the casing side wall, and the sliding is in sliding contact with the mechanical seal packing. a ring-shaped packing receiving member having the inner end face surface, to urge the mechanical seal packing side by the urging means, abutting the two sliding faces, the shaft portion in a state in which the inner circumferential portion in contact with the shaft portion The inner peripheral surface of the mechanical seal packing is separated from the minute gap by the inner portion where the gap with the shaft portion is a minute interval, and the inner end surface of the packing receiving member and the shaft portion. A mechanical seal formed by an outer portion constituting an annular pocket serving as a reservoir portion for leaking material .   A push-back member is provided on the casing side on the outer end surface of the packing receiving member, which is elastically supported by a spring so as to face the packing receiving member, and pushes back the packing receiving member separated from the mechanical seal packing by the reaction force of the spring. The mechanical seal according to claim 1.   The abutment member is fixed to the tip of the yoke, and the intermediate portion of the yoke is supported by a fulcrum erected from the bearing portion, and a spring is disposed between the base of the yoke and the casing side wall. The mechanical seal according to claim 2, wherein the mechanical seal is configured.   4. The mechanical seal according to claim 3, wherein the push-back member is elastically supported by a pre-loaded spring.   The mechanical seal according to claim 3 or 4, wherein the contact member is configured to contact the packing receiving member at a position offset with respect to the shaft axis.

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