JP7481277B2 - Sealing mechanism and raw material mixing device - Google Patents

Description

Article 30, paragraph 2 of the Patent Act applies. The application of Article 30, paragraph 2 of the Patent Act was announced at a preview event for machine manufacturers and trading companies held at the Kyushu Office of Nippon Eirich Co., Ltd. (4-9-1 Minamifutajima, Wakamatsu-ku, Kitakyushu-shi, Fukuoka Prefecture) on September 12, 2019.

The present invention relates to a sealing mechanism that seals the gap between a rotating container that contains raw materials and rotates and a lid member that closes the upper opening of the rotating container, and a raw material mixing device equipped with the sealing mechanism.

The raw material mixing device is a device that performs various processes such as granulation, coating, mixing, kneading, stirring, and drying of raw materials, and is used in various industrial fields such as pharmaceuticals, chemicals, food, cosmetics, fine chemicals, castings, building materials, paints, and dust processing (see, for example, Patent Document 1 and Patent Document 2). This raw material mixing device is equipped with a rotating container that is rotated around an axis, a lid member that opens and closes the upper opening of the rotating container, and a sealing mechanism that seals the gap between the rotating container and the lid member. The rotating container generally has a cylindrical shape with a bottom. The raw materials to be processed by the raw material mixing device are fed into the rotating container from the upper opening of the rotating container, and then the upper opening of the rotating container is closed by the lid member. The rotating container is rotated at a predetermined rotation speed to perform the various processes.

The sealing mechanism prevents leakage of raw materials from the gap between the rotating vessel and the lid member and prevents foreign matter from entering the rotating vessel from the outside while various processes are being performed. Such a sealing mechanism has a sealing member connected to the underside of the lid member, and the sealing member is pressed against the inner circumferential surface of the rotating vessel with a predetermined pressing force. While various processes are being performed by the raw material mixing device, the rotating vessel into which the raw materials have been charged is rotated, but the lid member and the sealing member connected to the lid member are not rotated. Hereinafter, the inner circumferential surface of the rotating vessel against which the sealing member is pressed may be referred to as the "sealing surface."

In this specification, the materials fed into the rotating vessel of the raw material mixing device are collectively referred to as "raw materials." The raw materials may be solid materials such as powder and sludge, liquid materials such as water and oil, or a mixture of solid and liquid materials. In addition, in the raw material mixing device, each of the multiple materials may be fed into the rotating vessel at a predetermined time interval. For example, a solid material may be fed into the rotating vessel, the rotating vessel may be rotated, and then a liquid material may be fed into the rotating vessel after a predetermined time has elapsed. In this case, the raw materials are solid and liquid materials. In addition, in this specification, the objects removed from the rotating vessel after various processes are performed are collectively referred to as "products."

JP 2013-17923 A JP 2016-2536 A

In order for the sealing mechanism of the raw material mixing device to exhibit the appropriate sealing performance, the sealing member must be pressed against the rotating container with an appropriate pressing force. For example, if the sealing member is a lip seal, the tip of the lip must be pressed against the sealing surface of the rotating container with a specified pressing force.

However, the pressing force required to prevent leakage of the raw material from the rotating vessel varies depending on the properties of the raw material fed into the rotating vessel (e.g., the specific gravity, particle size, and moisture content of the raw material). For example, when light, finely granular raw material is processed in the rotating vessel, the raw material has a high degree of buoyancy, so the pressing force pressing the sealing member against the sealing surface of the rotating vessel is large.

The greater the magnitude of the pressing force, the more the sealing member and the sealing surface of the rotating container with which the sealing member comes into contact deteriorate and deform due to wear. Furthermore, there is a risk that more wear powder will be generated from the sealing member and the sealing surface. Deterioration of the sealing member and the sealing surface leads to a decrease in sealing performance and leads to leakage of raw materials from the rotating container. This increases the frequency of replacing the sealing member, which results in an increase in the running costs of the raw material mixing device. Furthermore, since the raw material mixing device is also used in the manufacturing process of products that do not tolerate the inclusion of foreign matter, such as food and medicine, there is a demand to reduce the generation of wear powder from the sealing member and the sealing surface as much as possible. Therefore, depending on the process performed by the raw material mixing device, it may not be possible to press the sealing member against the rotating container with a large pressing force.

Furthermore, the greater the magnitude of the pressing force, the greater the frictional heat generated between the sealing member and the sealing surface of the rotating vessel. If the generated frictional heat is transmitted to the raw material being processed through the rotating vessel, it may adversely affect the raw material. For example, if the raw material is a low-melting-point material, the raw material may melt. Therefore, there is a demand to reduce the pressing force that presses the sealing member against the rotating vessel as much as possible.

The present invention therefore aims to provide a sealing mechanism that can reduce the pressure that presses the sealing member against the rotating container. It also aims to provide a raw material mixing device equipped with such a sealing mechanism.

In one aspect, a sealing mechanism is provided that seals a gap between a rotating container that contains raw materials and rotates and a lid member that closes the upper opening of the rotating container, the sealing mechanism comprising a sealing member that is connected to the lid member and pressed against the rotating container, a barrier that is disposed radially inward of the sealing member, and a holder that connects the sealing member and the barrier to the lid member, the holder being formed with a flow path for introducing pressurized gas into the space between the sealing member and the barrier.

In one embodiment, the device further includes a seal monitoring mechanism that monitors deterioration of the sealing performance of the seal member.
In one aspect, the seal monitoring mechanism includes a pressure gauge that monitors the pressure in the space.
In one aspect, the seal monitoring mechanism includes a dust sensor capable of detecting the amount of the raw material that has entered the space.

In one aspect, the sealing member is a double lip seal having a first lip and a second lip pressed against the rotating container, the second lip being positioned radially outward of the first lip, and the flow path includes a first flow path for introducing a first pressurized gas into a first space between the first lip and the barrier, and a second flow path for introducing a second pressurized gas into a second space between the first lip and the second lip.
In one embodiment, the second pressurized gas has a pressure greater than a pressure of the first pressurized gas.
In one embodiment, the second pressurized gas has a pressure lower than a pressure of the first pressurized gas.
In one embodiment, the second pressurized gas has a pressure that is the same as the pressure of the first pressurized gas.

In one embodiment, the device further includes a seal monitoring mechanism that monitors deterioration of the sealing performance of the seal member.
In one embodiment, the seal monitoring mechanism includes a pressure gauge that monitors the pressure in the first space and/or the second space.
In one embodiment, the seal monitoring mechanism includes a dust sensor capable of detecting the amount of the raw material that has entered the first space and/or the second space.
In one embodiment, the sealing mechanism further includes a seal adjustment member for adjusting the distance between the sealing surface of the rotating container and the sealing member.

In one aspect, a raw material mixing device is provided that includes a rotating container that stores raw materials inside and rotates, a lid member that closes the upper opening of the rotating container, and the sealing mechanism, and is characterized in that the gap between the rotating container and the lid member is sealed by the sealing mechanism.

According to the present invention, pressurized gas introduced between the sealing member and the barrier forms an airflow that is sprayed toward the rotating container. This airflow can push back the raw material flowing toward the sealing member into the rotating container. In particular, the airflow can efficiently push back light, fine particulate raw material (highly buoyant raw material) into the rotating container. Furthermore, the airflow can prevent the raw material from adhering to the sealing member and the barrier. As a result, the raw material is prevented from reaching the sealing member, and the pressing force pressing the sealing member against the rotating container can be reduced.

FIG. 1 is a front view of a raw material mixing device according to one embodiment. FIG. 2 is a side view of the raw material mixing device shown in FIG. FIG. 3 is a schematic cross-sectional view for explaining a sealing mechanism according to one embodiment. FIG. 4 is a top view of the holder shown in FIG. FIG. 5 is a schematic cross-sectional view of the sealing mechanism as viewed in a cross section passing through the communication hole shown in FIG. FIG. 6 is a schematic cross-sectional view for explaining a sealing mechanism according to another embodiment. FIG. 7 is a top view of the holder shown in FIG. FIG. 8 is a schematic cross-sectional view of the sealing mechanism as viewed in a cross section passing through the first communication hole shown in FIG. 9 is a schematic cross-sectional view of the sealing mechanism as viewed in a cross section passing through the second communication hole shown in FIG. FIG. 10 is a schematic diagram showing an example of a seal monitoring mechanism included in the seal mechanism shown in FIG. 3 . FIG. 11 is a schematic diagram showing another example of the seal monitoring mechanism included in the seal mechanism shown in FIG. 3 . 12(a) and 12(b) are schematic diagrams showing an example of a seal monitoring mechanism provided in the seal mechanism shown in FIG. 6. FIG. 13(a) and 13(b) are schematic diagrams showing another example of the seal monitoring mechanism provided in the seal mechanism shown in FIG. 6. In FIG. FIG. 14 is an enlarged schematic view showing an example of a seal adjustment member.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
Fig. 1 is a front view of a raw material mixing device according to one embodiment. Fig. 2 is a side view of the raw material mixing device shown in Fig. 1. As shown in Figs. 1 and 2, the raw material mixing device includes a rotating container (mixing pan) 1 that accommodates raw materials and rotates, a first driving device (motor) 2 for rotating the rotating container 1, a rotor unit 3 that mixes the raw materials in the rotating container 1, and a second driving device (motor) 4 for rotating the rotor unit 3.

In this embodiment, the drive units 2 and 4 are connected to a control unit (not shown), and the control unit is configured to freely control the rotation speed and direction of the drive units 2 and 4. With this configuration, the rotating vessel 1 and the rotor unit 3 can be rotated independently at the desired rotation speed and direction.

The rotating vessel 1 has a cylindrical shape with a bottom, and is rotatably arranged inside the cover 9. In this embodiment, a lid member 5 is provided on the top of the cover 9, and the lid member 5 covers an opening formed at the upper end of the rotating vessel 1. As shown in FIG. 1, the lid member 5 has a supply port 5a for supplying raw materials to the rotating vessel 1. The raw materials may be supplied directly into the rotating vessel 1 from the supply port 5a, or the raw materials may be supplied to the rotating vessel 1 through raw material supply equipment (not shown) such as a chute, nozzle, or hopper connected to the supply port 5a and the raw materials may be supplied to the rotating vessel 1 via the raw material supply equipment and the supply port 5a. When manufacturing a product, the rotating vessel 1 into which the raw materials have been charged and the rotor unit 3 are rotated.

In the embodiment shown in Figs. 1 and 2, the cover 9 and the upper opening of the rotating container 1 are opened by the lid member 5 being raised in a direction parallel to the rotation axis of the rotating container 1 by a drive mechanism (e.g., an air cylinder, a hydraulic cylinder, or an electric cylinder) not shown. Although not shown, the cover 9 and the upper opening of the rotating container 1 may be opened and closed by the lid member 5 rotating about a pivot point. When the lid member 5 is raised and the upper opening of the rotating container 1 is opened, raw materials may be fed into the rotating container 1 from the upper opening. In this case, the supply port 5a may be omitted. When the product is to be removed from the rotating container 1, the lid member 5 may be raised to open the upper opening of the rotating container 1.

The lid member 5 does not need to open or close the upper opening of the rotating container 1 as long as it covers the upper opening. In this case, a discharge port (not shown) for removing the product from the rotating container 1 may be formed in the bottom wall or side wall of the rotating container 1. When a discharge port is provided in the rotating container 1, the raw material mixing device may have a discharge port gate capable of opening and closing the discharge port. When the product is removed from the rotating container 1, the discharge port gate is moved to open the discharge port. Furthermore, the raw material mixing device may have a suction line that can be connected to the discharge port. In this case, the product is sucked out of the rotating container 1 through the suction line connected to the discharge port.

The raw material mixing device rotates the rotating container 1, which has a predetermined amount of raw material put in and has its upper opening blocked by the lid member 5, and at the same time rotates the rotor unit 3 inside the rotating container 1, thereby carrying out various processes such as granulating, coating, mixing, kneading, stirring, and drying of the raw materials. While the raw material is being processed, the lid member 5 does not rotate even if the rotating container 1 and the rotor unit 3 rotate.

To prevent the raw materials from leaking from the gap between the rotating container 1 and the lid member 5 while the above process is being performed, the raw material mixing device has a sealing mechanism disposed between the rotating container 1 and the lid member 5. This sealing mechanism seals the gap between the rotating container 1 and the lid member 5.

Figure 3 is a schematic cross-sectional view for explaining a sealing mechanism according to one embodiment. The sealing mechanism 30 shown in Figure 3 has a sealing member 36 having a substantially ring shape. When the lid member 5 closes the upper opening of the rotating container 1, the sealing member 36 is pressed against the sealing surface 1a at the upper end of the rotating container 1. In the example shown in Figure 3, the sealing member 36 is a lip seal having a lip 36a that is pressed against the sealing surface 1a of the rotating container 1 and a lip seal body 36c to which the lip 36a is connected and has a ring shape. The lip 36a extends from the lower surface of the lip seal body 36c over the entire circumference of the lip seal body 36c. Therefore, when the lid member 5 closes the upper opening of the rotating container 1, the sealing member 36 seals the gap between the lid member 5 and the rotating container 1 over the entire circumference of the rotating container 1.

In the following description, the sealing mechanism 30 will be described with the sealing member 36 referred to as a lip seal 36, but the sealing member 36 of this embodiment is not limited to a lip seal as long as it is pressed against the sealing surface 1a of the rotating container 1. For example, the sealing member 36 may be a seal ring.

The sealing mechanism 30 further includes a cylindrical barrier 38 disposed radially inside the lip seal 36, and a holder 39 fixed to the lid member 5 while holding the lip seal 36 and the barrier 38. In this embodiment, the holder 39 has an annular shape. When the lid member 5 closes the upper opening of the rotating vessel 1, the central axis of the lip seal 36 and the central axis of the barrier 38 coincide with the central axis of the rotating vessel 1. The lip seal 36 is connected to the holder 39 via a fastener (not shown) such as a screw, with its inner surface in contact with the outer circumferential surface of the holder 39.

In the illustrated example, a flange portion that protrudes radially outward is formed at the upper end of the rotating container 1, and the inner peripheral surface of the flange portion functions as the seal surface 1a against which the lip 36a of the lip seal 36 is pressed. When the lid member 5 closes the upper opening of the rotating container 1, the tip of the lip 36a is pressed against the seal surface 1a of the rotating container 1 with a predetermined pressure force, causing the lip seal 36 to deform in the radial direction.

The lip seal (sealing member) 36 is selected from a material that has a certain degree of elasticity and can exhibit appropriate sealing performance. Such a material is, for example, synthetic rubber. The synthetic rubber that constitutes the lip seal 36 is preferably selected from synthetic rubbers that are widely used as materials for general sealing members. This is because the lip seal 36 can be manufactured inexpensively. Examples of such synthetic rubber include nitrile rubber (NBR), chlorosulfonated polyethylene (CSM), ethylene propylene rubber (EPM, EPDM), polyurethane (PU), and urethane rubber. Note that the material of the lip seal 36 is not limited to synthetic rubber as long as it has appropriate elasticity. For example, the lip seal 36 may be made of resin.

The barrier 38 has a flange 38a at its upper end that protrudes radially outward. The holder 39 has a step formed on the inner circumferential surface at its upper end in accordance with the shape of the flange 38a. With the flange 38a of the barrier 38 engaged with the step of the holder 39, the holder 39 is fixed to the cover member 5 by a plurality of screws 45. Specifically, the holder 39 has a screw hole 39a into which the screw 45 engages, and the cover member 5 has a through hole formed at a position corresponding to the screw hole 39a. With the screw 45 inserted into the through hole of the cover member 5, the screw 45 is screwed into the screw hole 39a of the holder 39, thereby fixing the holder 39 to the cover member 5. In FIG. 3, only one screw 45 and its screw hole 39a are drawn, but in reality, the holder 39 has a plurality of screw holes 39a arranged at equal intervals in the circumferential direction of the holder 39. Therefore, the holder 39 is fixed to the cover member 5 by a plurality of screws 45.

When the holder 39 is fixed to the lid member 5 by the screw 45, the flange portion 38a of the barrier 38 is sandwiched between the lid member 5 and a step formed on the holder 39, thereby connecting the barrier 38 and the lip seal 36 to the lid member 5 via the holder 39. When the lid member 5 to which the barrier 38 and the lip seal 36 are connected closes the upper opening of the rotating vessel 1, a small gap G is formed between the outer peripheral surface of the barrier 5 and the inner surface of the rotating vessel 1. In other words, the barrier 5 does not come into contact with the rotating vessel 1. The size of this gap G is, for example, a few mm (0.3 to 5 mm).

Figure 4 is a top view of the holder 39 shown in Figure 3. As shown in Figure 4, the holder 39 has a plurality of (five in Figure 4) communication holes 39b. These communication holes 39b form a flow path, which will be described later. In the example shown in Figure 4, the holder 39 has five communication holes 39b, but this embodiment is not limited to this example. For example, the holder 39 may have only one communication hole 39b. In other words, the holder 39 has at least one communication hole 39b.

Figure 5 is a schematic cross-sectional view of the sealing mechanism seen from a cross section passing through the communication hole 39b shown in Figure 4. In this embodiment, the communication hole 39b is a through hole extending from the upper surface to the lower surface of the holder 39. A through hole 5b is formed in the lid member 5 at a position corresponding to the communication hole 39b, and when the holder 39 is fixed to the lid member 5, the through hole 5b is connected to the communication hole 39b. A pressurized gas supply line 48 is connected to the through hole 5b of the lid member 5. An end of the pressurized gas supply line 48 is connected to a pressurized gas supply source (not shown), and pressurized gas is supplied to the through hole 5b via the pressurized gas supply line 48.

The pressurized gas supplied to the through hole 5b flows into the communication hole 39b formed in the holder 39. The communication hole 39b opens into the space formed between the barrier 38 (the outer peripheral surface) and the lip seal 36 (the inner peripheral surface of the lip 36a). Therefore, the pressurized gas supplied to the through hole 5b of the cover member 5 is released from the communication hole 39b into the space formed between the barrier 38 and the lip seal 36, filling the space. In this embodiment, the communication hole 39b functions as a flow path for introducing the pressurized gas into the space formed between the barrier 38 and the lip seal 36.

The space formed between the barrier 38 and the lip seal 36 is connected to the inside of the rotating vessel 1 via the gap G. Therefore, the pressurized gas filling this space forms an airflow that is ejected from the gap G into the rotating vessel 1. This airflow of pressurized gas can push back the raw material flowing toward the lip seal 36 into the rotating vessel 1. In particular, the airflow of pressurized gas can efficiently push back light, finely granular raw material (see FIG. 5) into the rotating vessel 1. Furthermore, the airflow can prevent the raw material from adhering to the lip seal 36 and the barrier 38. As a result, the raw material is prevented from reaching the lip seal 36, and the pressing force pressing the lip seal 36 against the seal surface 1a of the rotating vessel 1 can be reduced.

Furthermore, according to the sealing mechanism of this embodiment, the seal member 36 (lip 36a) is uniformly pressed against the seal surface 1a of the rotating container 1 by the pressurized gas. Therefore, even if the raw material passes through the gap G and enters the space formed between the barrier 38 and the lip seal 36, the raw material can be effectively prevented from leaking from the rotating container 1.

As shown in FIG. 5, the pressurized gas supply line 48 may be provided with a pressure regulating valve 50 or a flow regulator (e.g., a needle valve, a mass flow controller, etc.) 54. The pressure of the pressurized gas ejected from the gap G can be adjusted by the pressure regulating valve 50. The flow regulator 54 can adjust the flow rate of the pressurized gas ejected from the gap G. Thus, the pressure regulating valve 50 and the flow regulator 54 make it possible to adjust the pressure and flow rate of the pressurized gas according to the properties of the raw material in the rotating vessel 1. In one embodiment, the sealing mechanism 30 may have either the pressure regulating valve 50 or the flow regulator 54.

Figure 6 is a schematic cross-sectional view for explaining a sealing mechanism 30 according to another embodiment. The configuration of this embodiment that is not specifically explained is similar to the configuration of the above-mentioned embodiment, so the same or corresponding components are given the same reference numerals and redundant explanations are omitted.

The seal member 36 shown in FIG. 6 is a double lip seal (hereinafter simply referred to as a "lip seal") having a first lip 36a and a second lip 36b that are pressed against the seal surface 1a of the rotating container 1 when the lid member 5 closes the upper opening of the rotating container 1, and a lip seal body 36c. The lip seal 36 is connected to the holder 39 via a fastener (not shown) such as a screw, with its upper surface in contact with the lower surface of the holder 39.

The first lip 36a and the second lip 36b are pressed against the seal surface 1a of the rotating container 1. The second lip 36b is disposed radially outward of the first lip 36a. The first lip 36a and the second lip 36b extend from the lower surface of the lip seal body 36c around the entire circumference of the lip seal body 36c. Therefore, when the cover member 5 closes the upper opening of the rotating container 1, the first lip 36a and the second lip 36b of the lip seal 36 seal the gap between the cover member 5 and the rotating container 1 around the entire circumference of the rotating container 1.

In this embodiment, a block 47 having an annular shape is disposed between the base end of the first lip 36a and the base end of the second lip 36b. The inner peripheral surface of the block 47 contacts the outer peripheral surface of the first lip 36a, and the outer peripheral surface of the block 47 contacts the inner peripheral surface of the second lip 36b. When the cover member 5 closes the upper opening of the rotating container 1, the tips of the first lip 36a and the second lip 36b are pressed against the seal surface 1a of the rotating container 1 with a predetermined pressing force, and deform in the radial direction of the lip seal 36. On the other hand, the block 47 prevents the base end of the first lip 36a and the base end of the second lip 36b from deforming in the radial direction of the seal lip 36. In one embodiment, the block 47 may be omitted.

Figure 7 is a top view of the holder 39 shown in Figure 6. As shown in Figure 7, the holder 39 has a plurality of first communication holes 39b (five in Figure 4) and a plurality of second communication holes 39c (five in Figure 4). The first communication holes 39b form a first flow path, which will be described later, and the second communication holes 39c form part of a second flow path, which will be described later.

In the example shown in FIG. 7, the holder 39 has five first communication holes 39b, but this embodiment is not limited to this example. For example, the holder 39 may have only one first communication hole 39b. In other words, the holder 39 has at least one first communication hole 39b.

Figure 8 is a schematic cross-sectional view of the sealing mechanism taken along a cross section passing through the first communication hole 39b shown in Figure 7. In this embodiment, the first communication hole 39b is a through hole that extends while bending from the upper surface to the lower surface of the holder 39. A first pressurized gas supply line 48 is connected to the through hole 5b of the cover member 5. An end of the first pressurized gas supply line 48 is connected to a first pressurized gas supply source (not shown), and the first pressurized gas is supplied to the through hole 5b via the first pressurized gas supply line 48.

The first pressurized gas supplied to the through hole 5b flows into the first communication hole 39b formed in the holder 39. Furthermore, the first pressurized gas is released from the first communication hole 39b into the space (hereinafter referred to as the "first space") formed between the barrier 38 (its outer surface) and the first lip 36a (its inner surface) of the lip seal 36, filling the first space. In this embodiment, the first communication hole 39b functions as a first flow path for introducing the first pressurized gas into the first space.

The first space is connected to the inside of the rotating vessel 1 through the gap G. Therefore, the first pressurized gas filling the first space forms an airflow that is ejected from the gap G into the rotating vessel 1. This airflow of the first pressurized gas can push back the raw material flowing toward the lip seal 36 into the rotating vessel 1. In particular, this airflow of the first pressurized gas can efficiently push back light, finely granular raw material (see FIG. 5) into the rotating vessel 1. Furthermore, the airflow can prevent the raw material from adhering to the lip seal 36 and the barrier 38. As a result, the raw material is prevented from reaching the lip seal 36, and the pressing force that presses the lip seal 36 against the seal surface 1a of the rotating vessel 1 can be reduced.

Figure 9 is a schematic cross-sectional view of the sealing mechanism seen from a cross section passing through the second communication hole 39c shown in Figure 7. As shown in Figures 7 and 9, the holder 39 may have a second communication hole 39c. In this embodiment, the second communication hole 39c is a through hole that extends linearly from the upper surface to the lower surface of the holder 39. In the example shown in Figure 7, the holder 39 has five second communication holes 39c, but this embodiment is not limited to this example. For example, the holder 39 may have at least one second communication hole 39c.

A through hole 5c is formed in the lid member 5 at a position corresponding to the second communication hole 39c. When the holder 39 is fixed to the lid member 5, the through hole 5c is connected to the second communication hole 39c. A second pressurized gas supply line 49 is connected to the through hole 5c of the lid member 5. The end of the second pressurized gas supply line 49 is connected to a second pressurized gas supply source (not shown), and the second pressurized gas is supplied to the through hole 5c via the second pressurized gas supply line 49.

In this embodiment, the second communication hole 39c of the holder 39 is connected to the through hole 36d formed in the lip seal 36, and the through hole 36d formed in the lip seal 36 is connected to the through hole 47a formed in the block 47. Therefore, the second pressurized gas supplied to the through hole 5c via the second pressurized gas supply line 49 is introduced into the space (hereinafter referred to as the "second space") formed between the first lip 36a (the outer peripheral surface) and the second lip 36b (the inner peripheral surface) of the lip seal 36 through the second communication hole 39c of the holder 39, the through hole 36d of the lip seal 36, and the through hole 47a of the block 47. The second space is filled with the second pressurized gas. In this embodiment, the second communication hole 39b of the holder 39, the through hole 36d of the lip seal 36, and the through hole 47a of the block 47 function as a second flow path for introducing the second pressurized gas into the second space. In an embodiment in which the block 47 is omitted, the second communication hole 39b of the holder 39 and the through hole 36d of the lip seal 36 function as a second flow path for introducing the second pressurized gas into the second space.

In this embodiment, the second pressurized gas supply line 49 may also be provided with a pressure regulating valve 51 or a flow regulator (e.g., a needle valve, a mass flow controller, etc.) 55. The pressure of the second pressurized gas can be adjusted by the pressure regulating valve 51. The flow regulator 55 can adjust the flow rate of the second pressurized gas. In one embodiment, the sealing mechanism 30 may have either the pressure regulating valve 51 or the flow regulator 55.

The pressure of the second pressurized gas may be higher or lower than the pressure of the first pressurized gas. Alternatively, the pressure of the second pressurized gas may be the same as the pressure of the first pressurized gas.

When the second pressurized gas has a higher pressure than the first pressurized gas, the second pressurized gas filling the second space moves the first lip 36a toward the barrier 38, and the second space communicates with the first space. As a result, the second pressurized gas flows into the first space, and both the first and second pressurized gases are ejected from the gap G into the rotating vessel 1. Therefore, compared to an embodiment in which only the first pressurized gas is ejected from the gap G, the flow rate of the pressurized gas ejected from the gap G into the rotating vessel 1 increases, making it more difficult for the raw material to reach the lip seal 36. As a result, the pressing force pressing the lip seal 36 against the seal surface 1a of the rotating vessel 1 can be further reduced.

When the second pressurized gas has a lower pressure than the first pressurized gas, the first lip 36a can be more firmly and uniformly attached to the seal surface 1a of the rotating vessel 1 according to the pressure difference between the first and second pressurized gases. As a result, even if the raw material passes through the gap G, the first lip 36a prevents the raw material from entering the second space. Therefore, the pressing force that presses the lip seal 36 against the seal surface 1a of the rotating vessel 1 can be further reduced.

When the second pressurized gas has the same pressure as the first pressurized gas, the first lip 36a is pressed against the seal surface 1a of the rotating vessel 1 by its restoring force alone and does not move toward the barrier 38. In this case, compared to an embodiment in which the second pressurized gas has a pressure lower than that of the first pressurized gas, the amount of wear of the first lip 36a and the frictional heat generated between the first lip 36a and the rotating vessel 1 can be reduced. Therefore, the frequency of replacing the first lip 36a is reduced, and the running cost of the raw material mixing device can be reduced. Furthermore, the amount of wear powder mixed into the product is reduced. Compared to an embodiment in which the second pressurized gas has a pressure higher than that of the first pressurized gas, the second pressurized gas is prevented from flowing from the second space to the first space, and as a result, the consumption of the second pressurized gas can be reduced. As a result, the running cost of the raw material mixing device can be reduced.

Regardless of the relationship between the pressure magnitude of the first pressurized gas and the pressure magnitude of the second pressurized gas, the first pressurized gas is ejected from the gap G into the rotating vessel 1. This prevents the raw material from reaching the lip seal (sealing member) 36, thereby reducing the pressing force that presses the lip seal 36 against the seal surface 1a of the rotating vessel 1.

Furthermore, according to the sealing mechanism of this embodiment, the second lip 36b of the sealing member 36 is uniformly pressed against the sealing surface 1a of the rotating container 1 by the pressurized gas. Therefore, even if the raw material passes through the gap between the first lip 36a and the sealing surface 1a and enters the second space, the raw material can be effectively prevented from leaking from the rotating container 1.

The first pressurized gas may be the same gas as the second pressurized gas, or may be a different gas. For example, the first pressurized gas may be pressurized nitrogen, while the second pressurized gas may be compressed air different from the pressurized nitrogen. The raw materials in the rotating vessel 1 may contain materials that are altered (e.g., oxidized) when in contact with a large amount of air. In such a case, it is preferable to use an inert gas as the first pressurized gas to be sprayed into the rotating vessel 1. Examples of inert gases include nitrogen and argon. In one embodiment, carbon dioxide may be used as the first pressurized gas. When the second pressurized gas is sprayed into the rotating vessel 1 (i.e., when the second pressurized gas has a higher pressure than the first pressurized gas), it is preferable that the second pressurized gas is also an inert gas or carbon dioxide. On the other hand, when the second pressurized gas is not sprayed into the rotating vessel 1 (i.e., when the second pressurized gas has a lower pressure than the first pressurized gas), it is preferable to use compressed air, which is cheaper than inert gas and carbon dioxide, as the second pressurized gas to reduce the running costs of the raw material mixing device.

When raw materials are repeatedly processed in the raw material mixing device, the lip seal (sealing member) 36 of the sealing mechanism may deteriorate (e.g., wear or break), causing the sealing performance of the lip seal 36 to fall below the allowable range. The deterioration in sealing performance may lead to leakage of raw materials. Therefore, the sealing mechanism may have a seal monitoring mechanism that monitors the deterioration of the sealing performance of the lip seal 36.

Figure 10 is a schematic diagram showing an example of a seal monitoring mechanism provided in the sealing mechanism shown in Figure 3. The configuration of this embodiment that is not specifically described is similar to the above-mentioned embodiment, so duplicated descriptions will be omitted.

The seal monitoring mechanism 60 shown in FIG. 10 includes a pressure gauge 61 that measures the pressure in the space formed between the barrier 38 (its outer peripheral surface) and the lip seal 36 (its inner peripheral surface), and a pressure monitoring line 62 that connects the pressure gauge 61 to this space. The pressure monitoring line 62 is a pipe that extends from the pressure gauge 61 through the cover member 5 and the holder 39.

When the lip seal 36 deteriorates and its sealing performance decreases, the pressurized gas supplied to the space between the barrier 38 and the lip seal 36 leaks from the rotary vessel 1, and as a result, the pressure of the gas in the space between the barrier 38 and the lip seal 36 decreases. The pressure gauge 61 is connected to a control device (not shown), and the control device monitors the pressure of the gas in the space between the barrier 38 and the lip seal 36 based on the measured value sent from the pressure gauge 61. Specifically, the control device pre-stores a predetermined threshold value set according to the properties of the raw material, the pressure of the pressurized gas supplied to the space between the barrier 38 and the lip seal 36, etc., and monitors whether the pressure of the gas in the space is below this threshold value. For example, when the pressure of the pressurized gas supplied to the space between the barrier 38 and the lip seal 36 is 0.3 MPa, the control device monitors whether the pressure of the gas in the space is below 0.25 MPa. In this case, the predetermined threshold value is 0.25 MPa. The predetermined threshold value can be set arbitrarily depending on the properties of the raw material, the processing conditions performed by the raw material mixing device (e.g., the rotation speed of the rotating vessel 1), and the pressure of the pressurized gas, etc.

When the pressure in the space falls below a predetermined threshold, the control device issues an alarm to notify the operator of the deterioration of the sealing performance. This alarm allows the operator to check the condition of the lip seal 36 after the current process is completed, or to replace the lip seal 36. As a result, leakage of raw materials from the rotating vessel 1 due to deterioration of the lip seal 36 is prevented.

Figure 11 is a schematic diagram showing another example of a seal monitoring mechanism provided in the seal mechanism shown in Figure 3. The configuration of this embodiment that is not specifically described is similar to the embodiment shown in Figure 10, so duplicate descriptions will be omitted.

The seal monitoring mechanism 60 shown in FIG. 11 includes a dust sensor 71 that can measure the amount of raw material that has entered the space formed between the barrier 38 and the lip seal 36, and a dust monitoring line 72 that connects the dust sensor 71 to this space. The dust monitoring line 72 is a pipe that extends from the dust sensor 71 through the lid member 5 and the holder 39.

As described above, when the lip seal 36 deteriorates, the pressure of the gas in the space between the barrier 38 and the lip seal 36 decreases. Therefore, raw materials can easily enter this space. In this embodiment, the amount of raw materials that have entered the space between the barrier 38 and the lip seal 36 is monitored by the dust sensor 71 to monitor the deterioration of the lip seal 36. Specifically, the dust sensor 71 is connected to a control device (not shown), and the control device monitors the amount of raw materials that have entered the space between the barrier 38 and the lip seal 36 based on the measurement value sent from the dust sensor 71. The control device pre-stores a predetermined threshold value that is set according to the properties of the raw materials, the processing conditions performed by the raw material agitation device (e.g., the rotation speed of the rotating vessel 1), and the pressure of the pressurized gas, and issues an alarm when the measurement value of the dust sensor 71 exceeds this threshold value.

The predetermined threshold value is determined, for example, as follows: When the lip seal 36 is performing an appropriate sealing performance, the amount of raw material entering the space between the barrier 38 and the lip seal 36 is measured using the dust sensor 71. The predetermined threshold value is determined by multiplying this amount of raw material by a predetermined coefficient (for example, 1.5).

Even with this configuration, the operator can be informed of the deterioration of the lip seal 36 by the alarm. When the alarm is issued, the operator can check the condition of the lip seal 36 after the currently being executed process is completed, or can replace the lip seal 36. As a result, leakage of raw materials from the rotating vessel 1 due to deterioration of the lip seal 36 is prevented.

The seal monitoring mechanism 60 can also be provided in the seal mechanism described with reference to FIG. 6. FIGS. 12(a) and 12(b) are schematic diagrams showing an example of a seal monitoring mechanism provided in the seal mechanism shown in FIG. 6. The configuration of this embodiment that is not specifically described is similar to the embodiment described with reference to FIG. 10, and therefore a duplicate description will be omitted.

As shown in FIG. 12(a), the seal monitoring mechanism 60 includes a first pressure gauge 64 that measures the pressure in the first space formed between the barrier 38 (the outer peripheral surface of the barrier 38) and the first lip 36a (the inner peripheral surface of the lip seal 36), and a first pressure monitoring line 65 that connects the first pressure gauge 64 to the first space. The first pressure monitoring line 65 is a pipe that extends from the first pressure gauge 64 through the cover member 5 and the holder 39. The first pressure gauge 64 is connected to a control device (not shown) and monitors the pressure of the gas in the first space.

As shown in FIG. 12(b), the seal monitoring mechanism 60 includes a second pressure gauge 66 that measures the pressure in the second space formed between the first lip 36a (the outer peripheral surface) and the second lip 36b (the inner peripheral surface) of the lip seal 36, and a second pressure monitoring line 67 that connects the second pressure gauge 66 to the second space. The second pressure monitoring line 67 is a pipe that extends from the second pressure gauge 66 through the cover member 5, the holder 39, the lip seal 36, and the block 47. The second pressure gauge 66 is connected to a control device (not shown) and monitors the pressure of the gas in the second space.

When the sealing performance of the lip seal 36 deteriorates, the pressure of the gas in the first space and the pressure of the gas in the second space decrease. A control device (not shown) monitors whether the pressure of the gas in the first space is equal to or lower than a predetermined first threshold and whether the pressure of the gas in the second space is equal to or lower than a predetermined second threshold. In this embodiment, the control device is configured to issue an alarm for deterioration of the lip seal 36 when the pressure of the gas in the first space is equal to or lower than a predetermined first threshold or when the pressure of the gas in the second space is equal to or lower than a predetermined second threshold.

With this configuration, the operator can be informed of the deterioration of the lip seal 36 by an alarm. When the alarm is issued, the operator can check the condition of the lip seal 36 after the currently executed process is completed, or can replace the lip seal 36. As a result, leakage of raw materials from the rotating vessel 1 due to deterioration of the lip seal 36 is prevented.

In one embodiment, the control device may be configured to issue an alarm for deterioration of the lip seal 36 when the pressure of the gas in the first space is equal to or lower than a predetermined first threshold and the pressure of the gas in the second space is equal to or lower than a predetermined second threshold. Alternatively, the seal monitoring mechanism 60 may include only one of the first pressure gauge 64 and the second pressure gauge 66. In this case, the pressure monitoring line connected to the omitted pressure gauge is also omitted.

Figures 13(a) and 13(b) are schematic diagrams showing another example of a seal monitoring mechanism provided in the seal mechanism shown in Figure 6. The configuration of this embodiment that is not specifically described is similar to the embodiment described with reference to Figures 12(a) and 12(b), so duplicated descriptions will be omitted.

The seal monitoring mechanism 60 shown in FIG. 13(a) and FIG. 13(b) has a first dust sensor 74 instead of the first pressure gauge 64, and a second dust sensor 76 instead of the second pressure gauge 66. The first dust sensor 74 communicates with the first space via a first dust monitoring line 75, and the second dust sensor 76 communicates with the second space via a second dust monitoring line 76.

As described above, the deterioration of the sealing performance of the lip seal 36 can also be determined by the amount of raw material measured by the dust sensor. The first dust sensor 74 and the second dust sensor 76 are connected to a control device (not shown), and the control device can issue an alarm to notify an operator of the deterioration of the lip seal 36 when the measurement value of the first dust sensor 74 is equal to or greater than a predetermined first threshold value or when the measurement value of the second dust sensor 76 is equal to or greater than a predetermined second threshold value.

In one embodiment, the control device may be configured to issue an alarm for deterioration of the lip seal 36 when the measurement value of the first dust sensor 74 is equal to or greater than a predetermined first threshold value and the measurement value of the second dust sensor 76 is equal to or greater than a predetermined second threshold value. Alternatively, the seal monitoring mechanism 60 may include only one of the first dust sensor 74 and the second dust sensor 76. In this case, the dust monitoring line connected to the omitted dust sensor is also omitted.

The sealing mechanism may have a seal adjustment member for adjusting the distance between the sealing surface 1a of the rotating container 1 and the lip 36a of the sealing member 36. Figure 14 is a schematic diagram showing an example of a seal adjustment member.

The rotating container 1 shown in FIG. 14 is composed of a container body 1b and a seal ring 1c connected to the upper end of the container body 1b. The above-mentioned seal surface 1a is formed on the seal ring 1c. The seal ring 1c is connected to the upper end of the flange-shaped container body 1b by a plurality of screws (connecting members) 81. More specifically, a through hole into which the screw 81 is inserted is formed at the upper end of the rotating container 1, and the seal ring 1c has a screw hole 1d formed at a position corresponding to the through hole. The screw hole 1d extends from the lower surface to the upper surface of the seal ring 1c. With the seal ring 1c placed on the upper surface of the flange-shaped container body 1b, the screws 81 are passed through the through holes and screwed into the screw holes 1d, thereby connecting the seal ring 1c to the container body 1b.

In FIG. 14, only one screw 81 and its screw hole 1d are shown, but in reality, the seal ring 1c has multiple screw holes 1d arranged at equal intervals in the circumferential direction of the seal ring 1c. Therefore, the seal ring 1c is connected to the container body 1b by multiple screws 81. When the seal ring 1c is connected to the container body 1b using multiple screws 81, the central axis of the seal ring 1c coincides with the central axis of the container body 1b.

In this embodiment, the connecting member for connecting the seal ring 1c to the container body 1b is a screw 81, but the connecting member is not limited to this example. For example, the connecting member may be a clip that clamps the flange-shaped upper end of the container body 1b of the rotating container 1 and the seal ring 1c.

The sealing mechanism has a container seal member 80 that is sandwiched between the bottom surface of the seal ring 1c and the top surface of the container body 1b to prevent leakage of raw materials from the gap between the seal ring 1c and the container body 1b. In this embodiment, the container seal member 80 is an O-ring. Note that the container seal member 80 is not limited to an O-ring as long as it is capable of preventing leakage of raw materials from the gap between the seal ring 1c and the container body 1b. For example, the container seal member 80 may be a resin seal plate.

As shown in FIG. 14, the sealing mechanism has a seal adjustment member (adjustment plate) 86 sandwiched between the rotating container 1 and the seal ring 33. The adjustment plate 86 functions as a so-called "shim" that adjusts the distance of the seal ring 1c (i.e., the rotating container 1) relative to the lip seal 36. The adjustment plate 86 shown in FIG. 14 has a ring shape. Furthermore, the adjustment plate 86 has a through hole 86a through which the screw 81 passes. The through hole 86a is provided corresponding to the through hole formed in the flange-shaped upper end of the rotating container 1. That is, the through hole 86a is formed corresponding to the screw 81 for connecting the seal ring 1c to the container body 1b.

By changing the thickness of the adjustment plate 46 (i.e., the size of the adjustment plate 46 in the direction of extension of the central axis of the seal ring 1c), the position of the seal ring 1c relative to the lip seal 36 (i.e., the distance between the lip seal 36 and the rotating container 1) can be changed. By using such an adjustment plate 46, the pressure with which the lip seal 36 is pressed against the seal ring 1c can be freely adjusted. For example, the thicker the adjustment plate 46 is made, the greater the pressure with which the lip seal 36 is pressed against the seal surface of the seal ring 1c.

Therefore, when the sealing performance of the lip seal 36 is reduced due to wear (for example, when the above-mentioned alarm is issued), the sealing performance of the lip seal 36 can be restored by sandwiching an adjustment plate 46 having a thickness according to the amount of deformation of the lip seal 36 and/or the seal ring 1c due to wear between the container body 1b and the seal ring 1c.

In FIG. 14, an example is described in which the sealing mechanism having the lip seal 36 shown in FIG. 6 has an adjustment plate (seal adjustment member) 46, but the sealing mechanism having the lip seal 36 shown in FIG. 3 may also have an adjustment plate 46.

The above-described embodiments have been described for the purpose of enabling a person having ordinary knowledge in the technical field to which the present invention pertains to practice the present invention. Various modifications of the above-described embodiments would naturally be possible for a person skilled in the art, and the technical ideas of the present invention may also be applied to other embodiments. Therefore, the present invention is not limited to the described embodiments, but is to be interpreted in the broadest scope in accordance with the technical ideas defined by the scope of the claims.

1 Rotating vessel (mixing pan)
2 First driving device 3 Rotor unit 4 Second driving device 5 Lid member 7 Base 9 Cover 30 Sealing mechanism 36 Lip seal (sealing member)
36a: First lip; 36b: Second lip; 36d: Through hole; 38: Barrier; 39: Holder; 39b: First communication hole; 39c: Second communication hole; 45: Screw (fixing device);
47 Block 48 First pressurized gas supply line 49 Second pressurized gas supply line 50, 51 Pressure regulating valve 54, 55 Flow regulator 60 Seal monitoring mechanism 61, 64, 66 Pressure gauge 62, 65, 67 Pressure monitoring line 71, 74, 76 Dust sensor 72, 75, 76 Dust monitoring line 86 Adjustment plate (seal adjustment member)

Claims (13)

A sealing mechanism that seals a gap between a rotating container that contains raw material and rotates and a lid member that closes an upper opening of the rotating container,
a seal member connected to the cover member and pressed against the rotary container;
a barrier disposed radially inward of the seal member;
a holder connecting the sealing member and the barrier to the lid member;
a flow path is formed in the holder for introducing pressurized gas into a space between the seal member and the barrier ;
A sealing mechanism characterized in that, when the lid member covers the upper opening of the rotating container, a gap that functions as an outlet for the pressurized gas is formed between the outer surface of the barrier and the inner surface of the rotating container . The sealing mechanism according to claim 1, further comprising a seal monitoring mechanism that monitors the deterioration of the sealing performance of the sealing member. The seal mechanism according to claim 2 , wherein the seal monitoring mechanism includes a pressure gauge for monitoring a pressure in the space. The sealing mechanism according to claim 2 or 3, characterized in that the seal monitoring mechanism includes a dust sensor capable of detecting the amount of the raw material that has entered the space. the seal member is a double lip seal including a first lip and a second lip that are pressed against the rotary container, the second lip being disposed radially outward of the first lip,
2. The sealing mechanism according to claim 1, wherein the flow passage includes a first flow passage for introducing a first pressurized gas into a first space between the first lip and the barrier, and a second flow passage for introducing a second pressurized gas into a second space between the first lip and the second lip. The sealing mechanism according to claim 5, characterized in that the second pressurized gas has a pressure higher than the pressure of the first pressurized gas. The sealing mechanism according to claim 5, characterized in that the second pressurized gas has a pressure lower than the pressure of the first pressurized gas. The sealing mechanism according to claim 5, characterized in that the second pressurized gas has the same pressure as the first pressurized gas. The sealing mechanism according to any one of claims 5 to 8, further comprising a seal monitoring mechanism for monitoring deterioration of the sealing performance of the sealing member. The seal mechanism according to claim 9, characterized in that the seal monitoring mechanism includes a pressure gauge that monitors the pressure in the first space and/or the second space. The sealing mechanism according to claim 9 or 10, characterized in that the seal monitoring mechanism includes a dust sensor capable of detecting the amount of the raw material that has entered the first space and/or the second space. The sealing mechanism according to any one of claims 1 to 11, further comprising a seal adjustment member for adjusting the distance between the seal surface of the rotating container and the seal member. A rotating container that accommodates raw materials therein and rotates;
a cover member for closing an upper opening of the rotary container;
The sealing mechanism according to any one of claims 1 to 12,
The raw material mixing device according to claim 1, wherein the sealing mechanism seals a gap between the rotating container and the lid member.

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