JP2007211741A - Shaft seal device of pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shaft seal of a pump whose life is remarkably extended by stopping the intrusion of a highly abrasive moving liquid from a seal to prevent the seal from being worn out by eliminating a difference in liquid pressure on both sides of the seal on the pump casing (liquid contact) side where wear is liable to occur, i.e., by keeping a pressure balance. <P>SOLUTION: This shaft seal device 10-1 of the pump is disposed around a rotating shaft 3 rotated by a drive motor 2 at a connected position between the drive side casing 5 and the pump casing 6 of the pump 1. Two seals 16, 17 are installed around the rotating shaft 3 at an interval in the axial direction. One seal 16 is brought into contact with the moving liquid F in the pump casing 6 and axially movable on the rotating shaft 3 within a specified range. The sealed space S between the one seal and the other seal 16 is formed in a lubricant-filled chamber 18. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pump that is rotated by a driving device such as a uniaxial eccentric screw pump or a rotary pump, and a driving casing having a driving shaft or a rotating shaft connected to the driving shaft directly or via a speed reduction mechanism, and a pump casing. Is placed around the drive shaft or rotating shaft (hereinafter simply referred to as the rotating shaft), and the gap between the rotating shaft and the surrounding casing (non-rotating portion) is sealed to prevent the ingress of the transferred liquid. More particularly, the present invention relates to a shaft seal device suitable for a pump that conveys a highly abrasive transfer liquid (for example, various slurries, dewatered cakes, and mortar).

  With respect to the prior art related to this type of shaft seal device, for example, a shaft seal of a pump disposed around a rotary shaft rotated by the drive device at a joint portion between the drive casing and the pump casing in a pump rotated by the drive device. In the apparatus, a lip packing (seal) can be fitted around the central opening of one seal support member of at least two annular seal support members mounted adjacent to each other on the outer peripheral surface of the rotating shaft. A shaft seal device having a structure in which an annular recess is formed and a lip packing is fitted in the annular recess has been proposed (see, for example, Patent Document 1). According to this shaft seal device, when the surface of the rotating shaft is worn or worn by the lip packing fitted on one side, the seal support member is replaced, and the lip packing is replaced with a new one. The position of the lip packing, i.e., the seal position, moves to a position where there is no wear or wear, so that the life of the rotating shaft is at least doubled and the shaft sealing action is restored to the state at the time of initial assembly. is there. However, even in the case of this shaft seal device, the lip packing and the rotating shaft wear out in a short period of time when used for transferring highly wearable liquid, so the position of the lip packing is frequently changed or replaced with a new one. It is necessary to replace the rotating shaft at an early stage.

Therefore, as shown in FIG. 6, two types of seal support members 47 and 48 to which a lip packing 44 having a substantially L-shaped cross section can be fitted are provided, and one seal support member 47 is a ring provided on the pump casing 46 side. The other seal support member 48 is loaded into the recess 49A and into the annular recess 49B provided on the drive side casing 45 side, and a lubricant sealing chamber 50 such as grease is inserted between the two recesses 49A and 49B. A shaft seal device having a structure in which the sealing chamber 50 is filled with a filler has been proposed (see also Patent Document 1).
JP 2003-56715 A (paragraphs 0018-0021, 0026-0028 and FIGS. 2 and 4)

  The shaft seal structure shown in FIG. 6 in the above-mentioned Patent Document 1 is considered to be the best at present. However, the shaft seal structure also has the following problems when it is applied to a pump that transfers a liquid with high wear resistance.

  In order to prevent cavitation during liquid transfer, it is necessary to apply a pushing pressure to the primary side (suction port side) of the pump. Therefore, a hydraulic pressure difference is generated between the transfer liquid F in the pump casing 46 and the lubricant G in the sealing chamber 50 with the lip packing 44 on the seal support member 47 side on the pump casing 46 side interposed therebetween, and the seal support member. The transfer liquid F enters from the gap between the lip packing 44 on the 47 side and the rotary shaft 3, and the lip packing 44 of the seal support member 47 is rubbed. Specifically, when the filler G is injected into the sealing chamber 50, the intrusion of air is unavoidable, so that the infiltrated air is compressed by the hydraulic pressure difference and allows the transport liquid to enter the seal (lip packing 44). It will be. As a result, the seal (lip packing 44) may be worn out in a very short period of time and liquid leakage may occur.

  The present invention has been made in view of the above points, and eliminates the hydraulic pressure difference by sandwiching a seal (packing) on the pump casing (wetted) side where wear is likely to occur. It is an object of the present invention to provide a shaft seal device for a pump that prevents the intrusion of a frictional transfer liquid, prevents the seal from being worn, and extends the service life significantly.

  In order to achieve the above object, a shaft seal device for a pump according to the present invention is arranged around a rotary shaft that is rotated by the drive device at a joint portion between the drive side casing and the pump casing in the pump that is rotated by the drive device. In the shaft seal device of the pump to be mounted, two seals are arranged around the rotary shaft at an interval in the axial direction, one seal is in contact with the transfer liquid in the pump casing, and It is configured to be slidable within a certain range in the axial direction on the rotating shaft, and a sealing space between the other seal is formed in the lubricant filling chamber.

  According to the shaft seal device of the pump of the present invention having the above-described configuration, liquid is transferred to the transfer hydraulic pressure (pressure) in the pump casing and the lubricant pressure (pressure) in the lubricant filling chamber across the seal on the pump casing side. When there is a pressure difference, the seal slides to the low pressure side along the rotation axis and stops at a position where the fluid pressure difference becomes zero. In this way, the hydraulic pressure is kept equal across the seal on the pump casing side, so when a highly frictional liquid (for example, various slurries, dehydrated cake) is transferred by the pump, it is pushed into the primary side to prevent cavitation. Even when pressure is applied, the liquid pressure (pump casing) side seal with severe wear is always balanced, and the pump casing transfer liquid is prevented from entering the lubricant filling chamber from the seal. In addition, the pressure in the lubricant filling chamber acts on the seal on the side opposite to the wetted seal (drive casing), but the seal is lubricated with a lubricant (such as grease). It is hard to be worn, and the life is significantly extended compared with the conventional structure.

  According to a second aspect of the present invention, an annular seal support member is slidable within a certain range in the axial direction on the rotary shaft, near the pump casing, around the rotary shaft in the lubricant filling chamber. The pump casing side seal is mounted on the inner peripheral surface side of the seal support member, and another annular seal is mounted on the outer peripheral surface side, and the rotating shaft is mounted on the seal support member. An anti-rotation member for preventing the rotation due to the rotation can be attached.

  With this configuration, the volume of the lubricant filling chamber between the opposing seals around the rotating shaft can be increased to increase the amount of filler injection, and on the pump casing side, the seal on the inner and outer peripheral surfaces of the seal support member can be increased. Prevent ingress of transfer liquid. In the shaft seal device according to the present invention, the pump casing side seal support member slides to the low pressure side comparing the pressure of the liquid transferred in the pump casing and the pressure of the lubricant in the lubricant filling chamber, and the hydraulic pressure difference becomes zero. Kept in position. As a result, similar to the shaft seal device of the first aspect, the life of the seal can be greatly extended even if the transfer liquid is a high wear liquid.

  According to a third aspect of the present invention, an annular seal support member is slidable within a certain range in the axial direction on the rotary shaft, near the pump casing, around the rotary shaft in the lubricant filling chamber. An annular seal is attached to each of the inner peripheral surface (rotating shaft) side and the outer peripheral surface (drive casing) side of the seal support member, and the seal support member is opposite to the pump casing. A plurality of rotating bodies are rotatably mounted on the peripheral surface at intervals in the circumferential direction, and each rotating body is brought into contact with the outer peripheral surface of the rotary shaft and the inner peripheral surface of the drive-side casing to rotate the rotary shaft. The planetary rotation can be made with.

  If constituted in this way, in addition to the same effects as the inventions of the first and second aspects, instead of receiving all the rotation of the rotating shaft by the seal on the inner peripheral surface side of the support member as in the first and second aspects. The rotating body performs planetary rotation, and the seal support member is rotated in the same direction as the rotating shaft at a speed of approximately 1/2 (when the outer diameter of the rotating body is set to 1/2 of the outer diameter of the rotating shaft). As a result, the inner and outer peripheral seals are worn almost evenly to extend the service life. On the other hand, in the shaft seal device of the second aspect, only the inner peripheral surface side of the seal support member is worn.

  5. The lubricant filling chamber according to claim 4, wherein the lubricant filling chamber is formed in an annular shape, and another opening is provided at a position facing the lubricant injection port (possible even at a non-facing position). An openable / closable stopper can be attached to the.

  With this configuration, by injecting the lubricant into the lubricant filling chamber from the injection port with another opening opened, it is possible to efficiently and sufficiently inject only the filler and prevent air contamination. It can be minimized.

  The shaft seal device of the pump according to the present invention has the following excellent effects. That is, the pump casing side seal is provided so as to be slidable in the axial direction of the rotary shaft, and the pressure is balanced by the seal being displaced to the low pressure side due to pressure fluctuation between the pump casing and the lubricant filling chamber across the seal. Since the configuration is adopted, the hydraulic pressure difference becomes 0 across the seal on the side in contact with the liquid in the pump casing, and therefore the liquid in the pump casing is prevented from entering the filler side from the seal. In addition, as for the other seal, the hydraulic pressure in the pump casing is added to the filler pressure, and a relatively high pressure acts. However, since the seal is in a state lubricated with a lubricant, it is difficult to wear. Compared to the conventional structure, the life is significantly extended. As a result, wear and abrasion of the seal members on both sides of the filler are prevented, and the seal member can be used stably for a long time.

  Embodiments of a shaft seal device for a pump according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a front view schematically showing an embodiment in which a shaft seal device according to an embodiment of the present invention is applied to a uniaxial eccentric screw pump, and FIG. 2A is an enlarged cross-sectional view of the shaft seal device of FIG. FIG. 2B is a cross-sectional view showing the main part of FIG.

  As shown in FIG. 1, a uniaxial eccentric screw pump 1 having a shaft seal device 10-1 (FIG. 2) of this example is operated by a rotating shaft (shaft) 3 connected to a drive shaft of an electric motor 2. Thus, the drive side casing 5 and the pump casing 6 that support the rotating shaft 3 are joined together. The pump casing 6 is provided with a suction port 7 in the upper part, and a connection port 8 with a uniaxial eccentric screw pump body at one end.

  The screw pump main body 31 has a known structure, and a male screw rotor 33 is fitted into the female screw hole 32a of the cylindrical stator 32 so as to be eccentrically rotatable. A stud end 34 protrudes from a discharge port 32b at the tip of the stator 32. Further, both ends of the connecting rod 35 are connected between the base end of the rotor 33 and one end of the rotary shaft 3 through pin joint universal joints 36 that enable eccentric rotation, respectively.

  As shown in FIG. 2, one end surface of the drive side casing 5 and one end surface of the pump casing 6 are joined so as to face each other, and are fastened and fixed by bolts and nuts (not shown) or the like. In both places, both casings 5 and 6 are formed in a cylindrical shape with their outer diameters enlarged in the radial direction, and an annular recess 9 is formed around the rotary shaft 3 at the joint location of both casings 5 and 6. In the annular recess 9, a space portion S is provided in the radial direction with respect to the outer peripheral surface of the rotary shaft 3, and a ring-shaped support housing 11 is fitted, and an O-ring 12 is interposed in the annular groove 11 a of the support housing 11. It is disguised. The support housing 11 constitutes a part of the outer peripheral wall of the drive-side casing 5, and a grease G inlet 13 as a filler is drilled through the support housing 11 in the radial direction, and is opposed to the inlet 13. Another grease injection port 14 is bored at a position where it is located. The inner ends of the inlets 13 and 14 reach the space portion S, and one (left side) of the space portion S communicates with the inside of the pump casing 6, and the other (right side) is a stopper ring portion 15 on the drive motor 2 side. And partitioned. Each inlet 13 and 14 is formed in a screw hole, and plugs (plugs) 13a and 14a having male screw portions are attached to be openable and closable, and are closed.

  An annular lip packing (seal) 16 is slidably disposed in the axial direction along the rotary shaft 3 at the communicating portion with the pump casing 6 in the space S, and is annular and has an L-shaped cross section on the other side. A lip packing (seal) 17 is disposed in contact with the stopper ring portion 15. A space between the two lip packings 16 and 17 is formed in the grease filling chamber 18.

  The operation mode of the uniaxial eccentric screw pump 1 according to the embodiment of the present invention configured as described above will be described below with a focus on the shaft seal device 10-1.

  When the rotating shaft 3 is rotated by the electric motor 2, the connecting rod rotates, and the rotor 33 rotates eccentrically within the female screw hole 32 a of the stator 32, thereby generating a pump action. The transfer liquid F is sucked into the pump casing 6 from the suction port 7 under the pushing pressure for preventing cavitation, and is sent out from the stud end 34 through the stator 32. At this time, the inside of the pump casing 6 is pressed against the suction pressure of the transfer liquid F, and the lip packing 16 contacting the transfer liquid F compares the internal pressure of the pump casing 6 and the internal pressure of the grease filling chamber 18 toward the low pressure side. Slide. And if it slides to the position where both internal pressures balance, the lip packing 16 will stop. In this state, the internal pressure on the pump casing 6 side and the internal pressure on the grease filling chamber 18 side are balanced, and the transfer liquid F on the pump casing 6 side is prevented from entering the grease filling chamber 18 from the lip packing 16.

  In the shaft seal device 10-1 according to the present embodiment, the two annular lip packings 16 and 17 that are in contact with the outer peripheral surface of the rotating shaft 3 and the inner peripheral surface of the support housing 11 are respectively manufactured and used. It has a simple structure, is compact, and is very advantageous in terms of cost. Of course, even if the transfer liquid (supply / discharge liquid) F is a highly wearable liquid, the lip packing 16 is not easily rubbed, so it is less likely to be worn out or worn out, compared to a conventional shaft seal device (see FIG. 0). As a result, the life of the lip packings 16 and 17 is greatly extended, and can be used stably over a long period of time.

  FIG. 3 is a sectional view in which a shaft seal device 10-1 common to the above embodiment is applied to the gear pump 1-1. Since it is basically the same as that in the above embodiment, common members are denoted by the same reference numerals in the drawings and description thereof is omitted.

  Next, FIG. 4 is an enlarged cross-sectional view of a shaft seal device according to another embodiment of the present invention.

  As shown in FIG. 4, the shaft seal device 10-2 of this example is different from the shaft seal device 10-1 of the above embodiment in that the lip packing 16 on the pump casing 6 side is placed on the outer peripheral surface of the rotary shaft 3. The ring-shaped lip packing 19b is in contact with the L-shaped lip packing 19a in contact with the inner peripheral surface of the support housing 11, and the lip packing 19a is formed on the inner surface of the annular seal support member 20 (on the pump casing 6 side). The lip packing 19b is mounted on the outer peripheral surface. The seal support member 20 is slidable in the axial direction of the rotary shaft 3 in the space S integrally with the lip packings 19a and 19b. Further, in order to prevent the seal support member 20 from rotating, a rotation prevention pin 21 is projected on the opposite surface to the drive motor 2 side, and a ring block 22 having a long hole 22a into which the rotation prevention pin 21 can be inserted is attached to an O-ring 23. Is fitted on the drive motor 2 side in the space S. Thus, the space between the two lip packings 19a and 19b and the L-shaped lip packing 17 on the side of the drive motor 2 serves as a grease filling chamber 24.

  In the case of this example, the pump casing 6 side includes a lip packing 19 a in contact with the outer peripheral surface of the rotary shaft 3 and a lip packing 19 b in contact with the inner peripheral surface of the support housing 11, and the hydraulic pressure in the pump casing 6 and the grease filling chamber 24 are provided. The seal support member 20 slides to the low pressure side compared to the hydraulic pressure of the two, and the slide of the seal support member 20 stops when both hydraulic pressures become equal. Since other configurations are the same as those of the shaft seal device 10-1, the common members are denoted by the same reference numerals in FIG.

  The grease filling chamber 24 of the shaft seal device 10-2 of this example has a larger volume than the grease filling chamber 18 of the shaft seal device 10-1, and also has a ring-shaped lip packing 19a that contacts the transfer liquid F on the pump casing 6 side. -Since the area of 19b is large, the change of the internal pressure of the pump casing 6 can be reflected more sensitively and accurately (high accuracy) in the internal pressure of the grease filling chamber 24. About another operation mode, since it is common with the shaft seal device 10-1 of the said Example, description is abbreviate | omitted.

  FIG. 5 is an enlarged cross-sectional view of a shaft seal device according to still another embodiment of the present invention.

  As shown in FIG. 5, the shaft seal device 10-3 in this example rotates the annular seal support member 20 at a speed of ½ with the rotation of the rotation shaft (shaft) 3 in the shaft seal device 10-2. The two (inner and outer ring) ring-shaped lip packings 19a and 19b attached to the seal support member 20 rotate half (half) relative to the rotary shaft 3 and the support housing 11. It is. For this reason, a plurality (four in this example) of bearings 25 having outer rings 25a formed of an elastic body are arranged at equal intervals in the circumferential direction on the circumferential surface of the seal support member 20 opposite to the lip packings 19a and 19b. A shaft (pin) 26 is rotatably attached to the shaft. Further, the outer diameter of the bearing 25 is set to ½ of the outer diameter of the rotary shaft 3. On the other hand, the locking pin is omitted, and the housing block 22 is not provided with the long hole 22a. Since other configurations are common, common members are denoted by the same reference numerals as those used in FIG. 4 and description thereof is omitted.

  An operation | movement aspect is demonstrated about the shaft-seal apparatus 10-3 of this example which consists of said structure.

  As shown in FIG. 5, the seal support member 20 is provided with lip packings 19 a and 19 b on the inner and outer peripheral portions of the circumferential surface on the pump casing 6 side, and these lip packings 19 a and 19 b serve as transfer liquid in the pump casing 6. Contact F. When the hydraulic pressure in the pump casing 6 and the internal pressure in the grease filling chamber 24 are compared across the lip packings 19a and 19b, the seal support member 20 slides with the bearing 25 on the low pressure side, and both hydraulic pressures are Stop at equal position. As a result, the hydraulic pressure difference between the two lip packings 19a and 19b becomes zero, so that the transfer liquid F in the pump casing 6 does not enter the grease filling chamber 24 side from the lip packings 19a and 19b.

On the other hand, the rotary shaft 3 rotates at a constant speed by the operation of the pump 1 (see FIG. 1). However, as shown in FIGS. 5C and 5D, the bearing 25 rotates in a planetary direction in the opposite direction, and the seal support member 20 The rotating shaft 3 rotates in the same direction as the rotating shaft 3 at a half speed. As a result, the inner peripheral surface side lip packing 19 a of the seal support member 20 is half the rotational speed of the rotary shaft 3, and the outer peripheral side lip packing 19 b of the seal support member 20 is relative to the support housing 11. It rotates at a rotation speed (1/2 rotation speed of the rotation shaft 3). For this reason, the wear is halved compared to the inner peripheral lip packing 19b in the shaft seal device 10-2. Further, since the lip packing 17 on the opposite side is in a circulating state with the grease G like the shaft sealing devices 10-1 and 10-2, there is a difference in rotational speed that is the same as the rotational speed of the rotary shaft 3, but wear. Hard to do.

As mentioned above, although the shaft seal device of the pump of the present invention has been described with reference to the three embodiments, it can be implemented as follows.

  -Although the uniaxial eccentric screw pump and the gear pump were illustrated and demonstrated, the kind of pump is not limited, For example, it can apply also to the shaft seal apparatus of a vortex pump.

The same applies to the case where the transfer liquid F is sucked from the stud end 34 and discharged from the suction port 7.

It is a front view which shows roughly the embodiment which applied the shaft seal device concerning the example of the present invention to the uniaxial eccentric screw pump. 2A is an enlarged cross-sectional view of the shaft seal device of FIG. 1, and FIG. 2B is an enlarged cross-sectional view of the main part of FIG. 2A. It is sectional drawing which applied the shaft seal apparatus 10-1 common to the said Example to the gear pump 1-1. 4A is an enlarged cross-sectional view showing a shaft seal device of a single-shaft eccentric screw pump according to another embodiment of the present invention, and FIG. 4B is a further enlarged view of the main part of FIG. 4A. FIG. FIG. 5A is an enlarged cross-sectional view showing a shaft seal device of a single-shaft eccentric screw pump according to still another embodiment of the present invention, and FIG. 5B is a further enlarged view of the main part of FIG. 5 (c) is a view taken in the direction of arrow A in FIG. 5 (a), and FIG. 5 (d) is a diagram illustrating the rotational directions of the rotary shaft 3, the seal support member 20, and the bearing 25. is there. It is sectional drawing which expands and shows the conventional shaft seal apparatus (a part of pump) considered to be the most excellent structure at present.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Uniaxial eccentric screw pump 2 Electric motor 3 Rotating shaft 5 Drive side casing 6 Pump casing 7 Suction port 8 Connection port 9 Recess 10-1, 10-2, 10-3 Shaft seal device 11 Support housing 12, 23 O-ring 13・ 14 Grease inlet 15 Stopper ring 16 ・ 17 ・ 19a ・ 19b Lip packing (seal)
18.24 Grease filling chamber (lubricant filling chamber)
20 Seal support member 21 Non-rotating pin 22 Housing block 25 Bearing 26 Support shaft (pin)
31 Pump body 32 Cylindrical stator 33 Male screw rotor

Claims (4)

In the shaft seal device of the pump disposed around the rotating shaft that is rotated by the driving device at the joint portion between the driving casing and the pump casing in the pump rotated by the driving device,
Around the rotating shaft, two seals are arranged at an interval in the axial direction, and one seal is brought into contact with the transfer liquid in the pump casing and is fixed on the rotating shaft in the axial direction. A shaft seal device for a pump, characterized in that it is configured to be slidable within the range and a sealed space between the other seal is formed in the lubricant filling chamber. An annular seal support member is slidably disposed on the rotary shaft within a certain range in the axial direction near the pump casing around the rotary shaft in the lubricant filling chamber. An annular pump casing side seal is mounted on the inner peripheral surface side, and another annular seal is mounted on the outer peripheral surface side. The shaft seal device for a pump according to claim 1, wherein a stop member is attached. An annular seal support member is slidably disposed on the rotary shaft within a certain range in the axial direction near the pump casing around the rotary shaft in the lubricant filling chamber. A plurality of rotating bodies are rotatably mounted on a circumferential surface opposite to the pump casing at intervals in the circumferential direction, and the rotating bodies are attached to the rotating shaft outer circumferential surface and the drive-side casing inner circumferential surface. The shaft seal device for a pump according to claim 2, wherein the shaft is rotated by planetary rotation by contact with the rotation shaft. The lubricant filling chamber is formed in an annular shape, provided with another opening in addition to the lubricant inlet, and an openable / closable stopper is attached to the opening and the inlet. A shaft seal device for a pump according to any of the above.

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