JP7455451B1 - Rotating shaft seal structure - Google Patents

Abstract

The present invention provides a rotary shaft seal structure that can be used under high pressure and does not require long-term maintenance. A first seal member 25 that seals between a rotating body 23 and a casing 21; a second seal member 26 that is located outside the first seal member 25 and seals between a rotating shaft 24 and a casing 21; , a steam input space 212 into which steam is input from the steam input port 211, and a condensing decompression chamber 216 cooled by the refrigerant from the refrigerant input port 214, and steam is input into the steam input space 212 from the steam input port 211. By doing so, the pressure in the steam input space 212 is set to be equal to or higher than that of the pressurized space 22, and the raw material and steam in the pressurized space 22 are prevented from moving toward the steam input space 212, and the pressure is removed from the second seal member 26. By condensing and reducing the pressure of the leaked steam in the condensing and depressurizing chamber 216, leakage of steam to the outside of the casing 21 is prevented. [Selection diagram] Figure 2

Description

The present invention relates to a rotating shaft seal structure for an apparatus having a rotating body that rotates together with a rotating shaft in a pressurized space pressurized by steam.

Conventionally, a rotary valve for transferring raw materials to an input port of a pressure steaming apparatus is known (for example, Patent Document 1 below). Since the rotary valve is highly airtight, it is possible to transfer the raw material to the input port while maintaining the pressure inside the pressure steaming device. In a rotary valve, a rotating body (blade and sidewall) rotates together with a rotating shaft inside a casing. In addition, in a pressurized steaming apparatus that employs a screw device for transporting raw materials as the main body, a rotating body (screw blade) rotates together with the rotating shaft within the casing of the device.

In both rotary valves and screw devices, the rotating shaft passes through the casing, and the space between the casing and the rotating shaft is sealed with a sealing member such as gland packing to ensure airtightness. More specifically, by sealing with a sealing member, raw materials and steam inside the rotary valve and the screw device are prevented from leaking out of the casing. For this reason, a seal between the casing and the rotating shaft has been essential for both rotary valves and screw devices.

Patent No. 5932387

However, sealing members such as gland packing harden after a certain period of time and their sealing performance deteriorates, so it is necessary to periodically replace the sealing members. For this reason, in a pressure steaming apparatus that performs steaming using high-pressure steam, maintenance becomes more frequent. Furthermore, there is a limit to the improvement in sealing performance with only a seal structure in which a seal member is interposed between the casing and the rotating shaft as described above.

The present invention solves the conventional problems as described above, and provides a rotary shaft seal structure that can be used under pressure, especially high pressure, and does not require long-term maintenance. The purpose is to provide.

To achieve the above object, the rotary shaft seal structure of the present invention is a rotary shaft seal structure for an apparatus having a rotating body that rotates integrally with the rotary shaft in a pressurized space pressurized by steam, a rotating shaft, the rotating body, a casing through which the rotating shaft passes, a first seal member that seals between the rotating shaft or the rotating body and the casing; a second seal member located outside the seal member and sealing between the rotating shaft or the rotating body and the casing; a steam inlet provided in the casing; a steam input space located between the seal member and the second seal member, provided in the casing to surround the rotating shaft or the rotating body, and into which steam from the steam input port is input; and the casing; a refrigerant inlet located outside the second seal member in the axial direction of the rotating shaft and provided in the casing to surround the rotating shaft or the rotating body; a condensing decompression chamber cooled by a refrigerant, and by injecting steam into the steam input space from the steam input port, the steam input space is brought to the same pressure or higher as the pressurized space, and the pressure is increased. By preventing the raw material and steam in the space from moving toward the steam input space, and by condensing and reducing the pressure of the leaked steam leaking from the second sealing member in the condensing and depressurizing chamber, the steam is released from the casing. It is characterized by preventing leakage of.

According to the rotary shaft seal structure of the present invention, in addition to the first seal member and the second seal member, the steam input space and the condensing pressure reduction chamber are provided, so that leakage of raw materials and steam to the outside of the casing can be prevented. can. As a result, the rotary shaft seal structure of the present invention can be used under high pressure and does not require maintenance for a long period of time.

Specifically, by injecting steam into the steam input space from the steam input port, the pressure in the steam input space is made equal to or higher than that of the pressurized space, and the raw materials and steam in the pressurized space move toward the steam input space. can be prevented. Further, even if steam leaks from the second sealing member, the leaked steam is condensed and depressurized in the condensing and depressurizing chamber and is discharged as a steam condensation drain, so that direct leakage of steam to the outside of the casing can be prevented.

FIG. 1 is a configuration diagram of a pressure steaming apparatus to which a rotary shaft seal structure according to an embodiment of the present invention is adopted. FIG. 1 is a sectional view showing a rotary shaft seal structure according to an embodiment of the present invention. FIG. 3 is a cross-sectional view showing another embodiment of the rotary shaft seal structure. FIG. 3 is a sectional view showing another embodiment of the rotary shaft seal structure of the present invention. FIG. 5 is an enlarged view of the main parts of the rotary shaft seal structure shown in FIG. 4.

The present invention relates to a rotary shaft seal structure for an apparatus having a rotating body that rotates together with a rotary shaft in a pressurized space pressurized by steam. There are no particular limitations on the type of equipment that employs this rotary shaft seal structure. For example, devices employing the same structure include a rotary valve that transfers raw materials to the input port of a pressure steaming device, a screw device that conveys steamed raw materials, a conveyor device, and the like.

In this embodiment, first, an embodiment in which a rotary shaft seal structure according to the present invention is applied to a rotary valve will be described with reference to FIGS. 1, 2, and 3, and then, with reference to FIGS. 4 and 5. An embodiment in which a rotary shaft seal structure according to the present invention is adopted in a screw device will now be described.

FIG. 1 shows a configuration diagram of a pressure steaming apparatus 1 to which a rotary shaft seal structure according to an embodiment of the present invention is adopted. The pressure steaming apparatus 1 is used to steam raw materials (for example, grain raw materials) under pressure in a steam atmosphere. In the pressure steaming apparatus 1, an input rotary valve 13 is attached to a raw material input port 121 of a screw device 12, and a discharge rotary valve 14 is attached to a raw material discharge port 122.

The input rotary valve 13 includes a rotor 132 made up of a rotating shaft 24, a blade 231, and a side wall 232 (see FIG. 2) in a casing 131, and a plurality of pockets 133 formed by the rotor 132. Rotate inside. The discharge rotary valve 14 has a similar configuration and includes a casing 141, a rotor 142, and a pocket 143.

The screw device 12 includes a screw 124 in a casing 123 that transports raw materials. The screw 124 has a rotating shaft 1242 and a screw blade 1241 attached thereto. A joint portion 1242a of the rotating shaft 1242 is connected to a motor (not shown) as a power source via a joint (not shown). The screw device 12 is provided with a pressurized steam supply port 125, and pressurized steam is injected into the casing 123 from the pressurized steam supply port 125 (arrow b). As a result, the raw material is pressure-cooked within the casing 123 in a steam atmosphere.

In FIG. 1, the raw material is supplied toward the input rotary valve 13 (arrow a), and the raw material supplied to the input rotary valve 13 is supplied to the open pocket 133. Subsequently, the rotor 132 rotates to transport it toward the input port 121, pass through the input port 121, and input it toward the screw 124. The raw material is conveyed in the horizontal direction by the rotation of the screw 124, is introduced into the discharge port 122, and is then discharged by being transferred by the discharge rotary valve 14.

In the pressure steaming apparatus 1 shown in FIG. 1, pressurized steam is injected into the casing 123 from the pressurized steam supply port 125, so that the inside of the casing 123 becomes a pressurized space pressurized by the steam. Accordingly, a part of the inside of the casing 131 of the input rotary valve 13 connected to the screw device 12 also becomes a pressurized space pressurized by the steam. Similarly, a part of the inside of the casing 141 of the discharge rotary valve 14 also becomes a pressurized space pressurized by steam.

Although not shown in FIG. 1, in the input rotary valve 13, a rotating shaft 24 (see FIG. 2) passes through the casing 131. The same applies to the discharge rotary valve 14. As described above, the inside of each casing of the screw device 12, the input rotary valve 13, and the discharge rotary valve 14 becomes a pressurized space pressurized by steam. Therefore, in order to prevent raw materials and steam from leaking out of the casing, a seal structure is required between the rotating shaft or rotating body and each casing.

Specifically, if the starch syrup-like raw material leaks from the gap between the rotating shaft or the rotating body and the casing, the raw material will stick to the rotating shaft or the rotating body and the casing, which will require maintenance to remove the raw material. Furthermore, leakage of steam to the outside of the casing and condensed water from the leaked steam to the outside of the device may damage the environment around the equipment. Even if these problems could be solved by employing a sealing member, the sealing member would harden and its sealing performance would deteriorate, necessitating periodic replacement. Furthermore, when the device is used under high pressure, it may not be possible to ensure sealing performance. The rotating shaft seal structure according to the present invention is a structure that can be used under high pressure and does not require long-term maintenance, and will be described in detail below with reference to FIG. 2.

FIG. 2 is a sectional view showing a rotary shaft seal structure 2 according to an embodiment of the present invention, and is a sectional view taken along line AA of the input rotary valve 13 shown in FIG. 1 (a sectional view in the central axis direction of the rotor 132). corresponds to The rotary shaft seal structure 2 is also the structure of the input rotary valve 13 and the discharge rotary valve 14 shown in FIG. 1, but for convenience of explanation, it will be described as the rotary shaft seal structure 2. However, for simplicity, the rotor is not shown in cross section. Hereinafter, in FIG. 2, the structure of one of the pair of rotating shafts 24 will be described, but the structure of the other rotating shaft 24 is similar.

The rotating shaft seal structure 2 has an external appearance made up of a casing 21, and a pressurized space 22 is formed within the casing 21. The casing 21 includes a rotating body 23 that rotates within the pressurized space 22 . The rotating body 23 is composed of blades 231 and sidewalls 232 provided at both ends of the blades 231. The rotating body 23 rotates together with the rotating shaft 24. The rotating shaft 24 passes through the casing 21.

A first seal member 25 seals between the side wall 232 and the casing 21 . A second seal member 26 seals between the rotating shaft 24 and the casing 21 . That is, the second seal member 26 is located outside the first seal member 25 in the axial direction of the rotating shaft 24 .

Examples of the material for the first seal member 25 and the second seal member 26 include fluororesin, glass-filled fluororesin, and PEEK (Poly Ether Ether Ketone) resin.

The casing 21 is provided with a steam inlet 211, a steam input space 212, and a steam drain outlet 213. The steam injection space 212 is located between the first seal member 25 and the second seal member 26 in the axial direction of the rotating shaft 24, and is provided so as to surround the rotating shaft 24. Steam from the steam input port 211 is input into the steam input space 212 (arrow e), and condensed steam drain is discharged from the steam drain outlet 213 (arrow f).

A water cooling jacket 27 is built into the casing 21. The water cooling jacket 27 is located outside the second seal member 26 in the axial direction of the rotating shaft 24. The water cooling jacket 27 is a cylindrical body, and a space 271 is formed inside the cylindrical body. A refrigerant is introduced into the space 271 from the refrigerant inlet 214 provided in the casing 21 (arrow g). The refrigerant introduced into the space 271 is discharged from the refrigerant outlet 215 provided in the casing 21 (arrow h).

A condensing and depressurizing chamber 216 is formed in a space inside the cylindrical water cooling jacket 27 so as to surround the rotating shaft 24 . The inside of the condensing and depressurizing chamber 216 is cooled by the water cooling jacket 27 through which the refrigerant introduced from the refrigerant inlet 214 flows. Although the details will be described later, leaked steam leaking from the second seal member 26 flows into the condensing and depressurizing chamber 216, and this leaked steam is condensed and depressurized in the condensing and depressurizing chamber 216, and then the steam condensing drain outlet 217 (arrow i).

Although not shown in FIG. 2, in order to increase the efficiency of heat exchange between the condensing decompression chamber 216 and the water cooling jacket 27, the condensing decompression chamber 216 may have a structure with fins inside. Further, in the embodiment shown in FIG. 2, indirect cooling is employed in which the inside of the condensing pressure reduction chamber 216 is cooled by the water cooling jacket 27, but the present invention is not limited to this. For example, a structure in which a refrigerant such as water is directly introduced into the condensing and depressurizing chamber 216 may be used.

The rotary shaft seal structure 2 configured as described above is a structure for preventing raw materials and steam from leaking out of the casing 21. This will be specifically explained below with reference to FIG. 2.

In FIG. 2, a motor (not shown) serving as a power source is connected to a joint portion 24a of the rotating shaft 24 via a joint (not shown). When the rotating shaft 24 is rotationally driven by the motor, the rotating body 23 rotates within the pressurized space 22 . Therefore, the raw material is introduced into the rotating shaft seal structure 2 (arrow c), passes through the rotating body 23, and is discharged from the rotating shaft seal structure 2 (arrow d).

The inside of the pressurized space 22 is pressurized by steam. Therefore, there is a possibility that the starch syrup-like raw material leaks toward the rotating shaft 24 through the gap between the casing 21 and the sidewall 232. This leakage is mainly prevented by the first seal member 25 and the steam injection space 212.

Specifically, by injecting steam into the steam input space 212 from the steam input port 211, the pressure in the steam input space 212 is made equal to or higher than that of the pressurized space 22, and the raw materials and steam in the pressurized space 22 are transferred to the steam input space 212. This prevents it from moving to the 212 side. That is, by providing the steam input space 212 in addition to the first seal member 25, leakage of raw materials and steam from the pressurized space 22 can be prevented.

On the other hand, in this embodiment, since steam is injected into the steam injecting space 212 , if there is no seal structure outside the steam injecting space 212 , the steam in the steam injecting space 212 will flow outside the casing 21 along the rotating shaft 24 . leak to. This leakage is prevented by the second seal member 26, the condensing pressure reduction chamber 216, and the oil seal 218.

By providing the second seal member 26, it is possible to suppress the steam in the steam injection space 212 from leaking to the outside from the second seal member 26. The leaked steam leaking from the second sealing member 26 is condensed and depressurized in the condensing and depressurizing chamber 216, becoming a steam condensing drain, and is discharged from the steam condensing drain outlet 217 (arrow i). Therefore, leakage steam from the second seal member 26 can be prevented from leaking out of the casing 21.

In this embodiment, an oil seal 218 is provided outside the condensing pressure reduction chamber 216, but since the pressure inside the condensation pressure reduction chamber 216 is close to atmospheric pressure, the outside of the condensation pressure reduction chamber 216 is provided with a simple oil seal 218 or the like. A standard seal can be used for sufficient sealing. In other words, even if the oil seal 218 is not provided, leakage steam can be prevented from leaking out of the casing 21, so a configuration in which the oil seal 218 is omitted may be used.

According to the above, the rotary shaft seal structure 2 includes the steam input space 212 and the condensation decompression chamber 216 in addition to the first seal member 25, the second seal member 26, and the oil seal 218, so that the rotating shaft seal structure 2 is able to accommodate the casing of raw materials and steam. 21 can be prevented from leaking outside. As a result, the rotary shaft seal structure 2 can be used under high pressure, and there is no need for long-term maintenance.

Although one embodiment of the present invention has been described above, the embodiment is merely an example, and may be modified as appropriate. FIG. 3 is a sectional view showing another embodiment of the rotary shaft seal structure 2. As shown in FIG. In FIG. 2, the first seal member 25 is interposed between the casing 21 and the sidewall 232 that constitutes the rotating body 23, but as shown in FIG. 3(a), the first seal member 25 is , may be interposed between the casing 21 and the rotating shaft 24. The same applies to the structure without the sidewall 232.

Further, as shown in FIG. 3(b), the first seal member 25, the second seal member 26, and the steam injection space 212 are interposed between the casing 21 and the side wall 232 that constitutes the rotating body 23. Good too. Furthermore, in FIG. 2, the condensing pressure reduction chamber 216 is provided so as to surround the rotating shaft 24, but as shown in FIG. It's okay.

FIG. 4 is a sectional view showing a rotary shaft seal structure 2' according to another embodiment of the present invention. The rotary shaft seal structure 2' is also the structure of the screw device 12 shown in FIG. 1, but for convenience of explanation, it will be described as the rotary shaft seal structure 2'. However, for simplicity, the screw is not shown in the cross-sectional view. In the rotary shaft seal structure 2' shown in FIG. 4, those having the same configuration as the rotary shaft seal structure 2 shown in FIG.

The rotating shaft seal structure 2' has an external appearance made up of a casing 21, and a pressurized space 22 is formed within the casing 21. The casing 21 includes a rotating body 28 (screw blade) that rotates within the pressurized space 22 . The rotating body 28 rotates together with the rotating shaft 29. The rotating shaft 29 passes through the casing 21.

In FIG. 4, a motor (not shown) serving as a power source is connected to a joint portion 29a of the rotating shaft 29 via a joint (not shown). When the rotating shaft 29 is rotationally driven by the motor, the rotating body 28 rotates within the pressurized space 22 . Therefore, the raw material is introduced into the rotary shaft seal structure 2' (arrow j), transported in the horizontal direction by the action of the rotary body 28, and discharged from the rotary shaft seal structure 2' (arrow k).

FIG. 5 shows an enlarged view of essential parts of the rotary shaft seal structure 2' shown in FIG. 4. Hereinafter, the structure of one end of both ends of the rotating shaft 29 will be described, but the structure of the other end is similar. In FIG. 5, the inside of the pressurized space 22 is pressurized by steam. Therefore, there is a possibility that the starch syrup-like raw material leaks out of the casing 21 through the gap between the casing 21 and the rotating shaft 29. This leakage is mainly prevented by the first seal member 25 and the steam injection space 212.

Specifically, by injecting steam into the steam input space 212 from the steam input port 211, the pressure in the steam input space 212 is made equal to or higher than that of the pressurized space 22, and the raw materials and steam in the pressurized space 22 are transferred to the steam input space 212. This prevents it from moving to the 212 side. That is, by providing the steam injection space 212 in addition to the first seal member 25, leakage of raw materials and steam from the pressurized space 22 can be prevented similarly to the rotary shaft seal structure 2.

On the other hand, in this embodiment as well, steam is injected into the steam injecting space 212, so if there is no seal structure outside the steam injecting space 212, the steam in the steam injecting space 212 will flow along the rotating shaft 29 and outside the casing 21. leak to. Similar to the rotating shaft seal structure 2, these leaks are prevented by the second seal member 26, the condensing pressure reduction chamber 216, and the oil seal 218.

By providing the second seal member 26, it is possible to suppress the steam in the steam injection space 212 from leaking to the outside from the second seal member 26. The leaked steam leaking from the second sealing member 26 is condensed and depressurized in the condensing and depressurizing chamber 216, becoming a steam condensing drain, and is discharged from the steam condensing drain outlet 217 (arrow i). Therefore, leakage steam from the second seal member 26 can be prevented from leaking out of the casing 21.

Similar to the embodiment shown in FIGS. 2 and 3, in this embodiment, an oil seal 218 is provided outside the condensing pressure reduction chamber 216, but the pressure inside the condensation pressure reduction chamber 216 is close to atmospheric pressure. Therefore, the outside of the condensing and depressurizing chamber 216 can be sufficiently sealed with a simple seal such as the oil seal 218. In other words, even if the oil seal 218 is not provided, leakage steam can be prevented from leaking out of the casing 21, so a configuration in which the oil seal 218 is omitted may be used.

According to the above, the rotary shaft seal structure 2', like the rotary shaft seal structure 2, includes the first seal member 25, the second seal member 26, and the oil seal 218, as well as the steam injection space 212 and the condensing pressure reduction chamber 216. By providing this, leakage of raw materials and steam to the outside of the casing 21 can be prevented. As a result, the rotary shaft seal structure 2' can be used under high pressure, and there is no need for long-term maintenance.

As described above, the device equipped with the rotary shaft seal structure according to the present invention can be used under pressure, and in particular can be used under high pressure. Specifically, it can be used at 1.00 MPaG or less. It is generally considered difficult to seal a rotating shaft under high pressures of 0.30 to 1.00 MPaG, but according to the rotating shaft seal structure of the present invention, even under such high pressure, the casing of raw materials and steam can be sealed. This prevents leakage and eliminates the need for long-term maintenance. Therefore, the rotary shaft seal structure of the present invention can exhibit more superiority when used under high pressure of 0.30 to 1.00 MPaG.

Further, there is no particular restriction on the rotation speed of the device provided with the rotary shaft seal structure according to the present invention. Generally, a labyrinth seal is used as a sealing member for a rotating shaft of a high-speed rotating device, but a labyrinth seal is not suitable for a low-speed rotating device of about several hundred rpm. The rotary valve that transfers the raw material to the input port of the pressure steaming device, the screw device that conveys the steamed raw material, and the conveyor device that are described above as devices that adopt the same structure are devices that operate at a low rotation speed of 500 rpm or less, By applying the rotary shaft seal structure of the present invention, superiority can be exhibited even more.

1 Pressure steaming device 2,2' Rotating shaft seal structure 21 Casing
211 Steam inlet 212 Steam inlet space 213 Steam drain outlet 214 Refrigerant inlet 215 Refrigerant outlet 216 Condensation decompression chamber 217 Steam condensate drain outlet 218 Oil seal 22 Pressurized space 23 Rotating body 231 Vane 232 Side wall 24 Rotating shaft 25 First seal member 26 Second seal member 27 Water cooling jacket 28 Rotating body 29 Rotating shaft

Claims (1)

A rotating shaft seal structure for a device having a rotating body that rotates together with a rotating shaft in a pressurized space pressurized by steam,
the rotating shaft;
The rotating body;
a casing through which the rotating shaft passes;
a first sealing member that seals between the rotating shaft or the rotating body and the casing;
a second seal member located outside the first seal member in the axial direction of the rotating shaft and sealing between the rotating shaft or the rotating body and the casing;
a steam inlet provided in the casing;
It is located between the first seal member and the second seal member in the axial direction of the rotating shaft, and is provided in the casing so as to surround the rotating shaft or the rotary body, and is arranged to surround the rotating shaft or the rotating body, and to prevent steam from the steam input port. a steam injection space into which
a refrigerant inlet provided in the casing;
a condensing depressurizer located outside the second seal member in the axial direction of the rotating shaft, provided in the casing to surround the rotating shaft or the rotating body, and cooled by the refrigerant from the refrigerant input port; Equipped with a room,
By injecting steam into the steam input space from the steam input port, the pressure in the steam input space is equal to or higher than that of the pressurized space, and the raw material and steam in the pressurized space move toward the steam input space. A rotary shaft seal characterized in that the leakage steam leaking from the second seal member is condensed in the condensation and pressure reduction chamber to reduce the pressure, thereby preventing leakage of steam to the outside of the casing. structure.

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