JP6621693B2 - Mechanical seal and twin screw pump - Google Patents

Description

  The present invention relates to a mechanical seal used for a sanitary-oriented pump that conveys viscous liquid foods, pharmaceuticals, and the like, and a biaxial screw pump using the mechanical seal.

Conventionally, as a mechanical seal used for this type of pump, between the press-contact sliding surface of the rotary sealing ring and the press-contact sliding surface of the fixed sealing ring, from the inner periphery which is the liquid side to the outer periphery which is the atmospheric side. The outside type which is designed to prevent leakage of the liquid to be sealed is commonly used for rotary pumps.
Such an outside type mechanical seal is shown in FIG. The illustrated mechanical seal 51 is attached to the inside of a cylinder of the seal housing 52 via an O-ring 53 and a seal housing 52 disposed outside the rotary shaft R that is mounted and fixed in the shaft hole TA of the pump member T. Between the fixed sealing ring 3, the seat ring 4 mounted on the outer peripheral surface of the rotary shaft R on the atmosphere side V with respect to the fixed sealing ring 3, and between the inner peripheral surface 4A of the seat ring 4 and the outer peripheral surface of the rotary shaft R And a shaft packing 54 interposed therebetween. The seat ring 4 is slidably pressed against the pressure contact sliding surface 25 of the fixed sealing ring 3 by a coil spring or the like (not shown) to generate a sealing action.

  In this mechanical seal 51, the non-sealing liquid J whose pressure is increased by the pumping action of the pump member T faces the liquid side wall surface 3 A of the fixed sealing ring 3, which is the liquid side L, and is stopped by the shaft packing 54. . However, in the outside type mechanical seal 51, since the seal housing 52 and the stationary sealing ring 3 are arranged on the liquid side L near the pump member T, the inner peripheral surface 3B of the stationary sealing ring 3 and the seat ring 4 There must be a relatively large gap 55 between the inner peripheral surface 4A and the outer peripheral surface of the rotary shaft R. Therefore, if the non-sealing liquid J enters the long gap 55 up to the shaft packing 54, the non-sealing liquid J once entered cannot be washed out by CIP cleaning (stationary cleaning) or the like, and sanitary properties are easily lost. .

  On the other hand, the inside that prevents leakage of the sealed liquid from the outer periphery on the atmosphere side to the inner periphery on the liquid side between the pressure contact sliding surface of the rotary sealing ring and the pressure contact sliding surface of the fixed sealing ring A type of mechanical seal is known, and is often used for a twin screw pump or the like. Such an inside type mechanical seal is shown in FIG. The illustrated mechanical seal 61 is disposed in a cylindrical seal housing 2 disposed outside the rotation axis R. That is, the mechanical seal 61 includes a fixed-side sealing portion 23 provided on the seal housing 2 side and having the fixed sealing ring 3, and a rotating-side sealing portion 21 provided on the rotating shaft R side and having the rotary sealing ring 7. The contact surface pressure applying member 13 that slidably presses the rotary sealing ring 7 and the fixed sealing ring 3 is provided. The rotary shaft R is inserted into a shaft hole TA formed in the pump member T and is fixed to the pump member T integrally by screwing such as a bolt.

The rotating side sealing portion 21 includes a stopper ring 10c attached to the rotating shaft R, and a holding ring 8 attached to the atmosphere V side end of the stopper ring 10c so as to be movable in the direction along the ring axis S. A second seal ring 9 interposed between the holding ring 8 and the stopper ring 10c, a shaft packing 11, and a fixing screw 62 screwed into the female screw hole 63 of the stopper ring 10c. Configured. The fixing screw 62 is for fixing the stopper ring 10c directly to the rotation axis R. The rotational axis R of the portion where the stopper ring 10c is mounted has the same diameter throughout the axis S direction.
The fixed-side sealing portion 23 includes a cylindrical seat case 5 mounted in the seal housing 2, a circular ring-shaped seat ring 4 mounted in the seat case 5, an outer peripheral surface of the seat ring 4, and a seal. An O-ring 12 mounted between the inner peripheral surface of the housing 2 and a circular ring-shaped fixed sealing ring 3 fixed to the liquid side L end surface of the seat ring 4 are configured.
Such an inside-type mechanical seal with an emphasis on sanitary properties is described, for example, in Patent Document 1 below.

Registered Utility Model No. 3155565

However, in the inside-type mechanical seal 61 described above, the liquid to be sealed J on the liquid side L is between the liquid side wall surface 10F of the stopper ring 10c and the atmospheric side wall surface TC of the pump member T, and the inner peripheral surface of the stopper ring 10c. There is a problem in that it enters the gap between 10G and the outer peripheral surface of the rotating shaft R and enters the shaft packing 11 to make cleaning difficult. However, the inside-type mechanical seal 61 has a gap between the outer peripheral surface of the rotary shaft R because the inner peripheral surface 10G from the liquid side wall surface 10F of the stopper ring 10c to the shaft packing 11 is shorter than that of the outside-type. There is an advantage that the capacity is relatively small.
On the other hand, since the stopper ring 10c is fixed to the outer peripheral surface of the rotation shaft R by the fixing screw 62, the sealed liquid J passes through the minute gap between the female screw hole 63 and the fixing screw 62, and the stopper ring 10c. It may enter between the inner peripheral surface 10G and the outer peripheral surface of the rotation shaft R. Furthermore, there is a possibility that the fixing screw 62 is loosened due to use over time or vibration during operation, allowing further infiltration of the liquid J to be sealed or fixing the stopper ring 10c.

  The present invention has been made in view of the above-described conventional problems, and omits a fixing screw having many problems, and the sealed liquid is placed between the rotating ring unit and the pump member in the rotating ring unit. It is an object of the present invention to provide a mechanical seal capable of preventing entry into a gap between the peripheral surface and the outer peripheral surface of the rotary shaft, and a biaxial screw pump using the mechanical seal.

  In order to achieve the above object, an inside type mechanical seal according to the present invention includes a rotating ring unit mounted on a rotating shaft side and a rotating side sealing portion having a rotating sealing ring held by the rotating ring unit, A fixed side sealing portion disposed on the seal housing side, and a contact surface pressure applying member that slidably presses the rotary sealing ring and the fixed sealing ring of the fixed side sealing portion. An inside-type mechanical seal that prevents leakage of liquid to be sealed from the outer periphery to the inner periphery in the pressure-contact sliding surface with the sealing ring, the liquid side wall surface of the rotating ring unit, the rotating shaft or the rotating shaft An anti-rotation member for fixing the rotating ring unit in the circumferential direction of the ring with respect to the rotating shaft is disposed between the air side wall surface of the pump member fixed to the rotating member and the rotating ring unit. Sealed radially inward between the liquid side wall surface of the pump and the rotary shaft or the atmospheric side wall surface of the pump member fixed to the rotary shaft and at a radially outer position than the detent member. A first seal ring for preventing liquid leakage is provided, and a hole-side step portion having a large diameter on the atmosphere side portion and a small diameter on the liquid side portion is provided on the inner peripheral surface of the shaft hole through which the rotation shaft in the rotating ring unit is passed. A shaft-side step portion that is formed and engages with the hole-side step portion of the rotating ring unit and prevents the rotating ring unit from moving in the fixed sealing ring direction is formed on the outer peripheral surface of the rotating shaft. The configuration is as follows.

  Further, in the above configuration, the rotating ring unit includes a stopper ring mounted on the rotating shaft, and a holding ring that is mounted on the atmosphere side end of the stopper ring so as to be movable in the axial direction of the ring and holds the rotating sealing ring. The second seal ring is interposed between the stopper ring and the holding ring to prevent leakage of the liquid to be sealed in the axial direction of the ring, and the contact pressure applying member.

Then, before Ki構 formed, between the outer peripheral surface of the inner peripheral surface of the shaft hole formed in the stopper ring and the rotary shaft, a third seal ring to prevent leakage in the axial direction of the sealed fluid is deployed It is what.

  Furthermore, the biaxial screw pump according to the present invention includes a pair of pump screws that rotate in a non-contact screwing manner, a pair of pump screws that are accommodated in a non-contact manner, and a pump chamber between the pair of pump screws. A pump casing to be formed, and a bearing portion connected to the pump casing and rotatably supporting one end portions of a pair of pump screws in a cantilevered manner, and the pump casing in the region where the pump chamber is formed is covered An inlet for taking the sealing liquid into the pump chamber is provided, and a pump casing on the floating end side of the pair of pump screws is provided with a discharge port for discharging the sealed liquid transferred from the pump chamber, In the pump, the liquid to be sealed taken into the pump chamber from the intake port is transferred by the rotational drive of a pair of pump screws and discharged from the discharge port. The mechanical seal according to any one of claims 1 to 3 is disposed at a boundary portion between the bearing portion and the pump casing, a liquid side wall surface of a rotating ring unit of the mechanical seal, and a rotating shaft. Alternatively, the atmosphere side wall surface of the pump screw fixed to the rotating shaft is fixed in the ring circumferential direction via a rotation preventing member.

  According to the mechanical seal of the present invention, the rotating ring unit is fixed in the ring circumferential direction with respect to the rotating shaft by the rotation preventing member, so that the conventional fixing screw having many troubles such as liquid leakage can be omitted. . A first seal ring is disposed between the liquid side wall surface of the rotary ring unit and the rotary shaft or the atmospheric side wall surface of the pump member fixed to the rotary shaft and at a radially outward position from the rotation preventing member. Therefore, the sealed liquid can be prevented from entering the gap between the inner peripheral surface of the rotary ring unit and the outer peripheral surface of the rotary shaft from between the rotary ring unit and the pump member. At this time, the rotating ring unit is elastically pushed toward the atmosphere side by the first seal ring, but the hole-side step portion can be locked to the shaft-side step portion of the rotating shaft.

  Further, as a rotating ring unit, a stopper ring mounted on the rotating shaft, a holding ring for holding the rotating sealing ring, a second seal ring interposed between the stopper ring and the holding ring, and a contact pressure What is comprised from the provision member can be used.

  Usually, the intrusion of the liquid to be sealed between the inner peripheral surface of the stopper ring and the outer peripheral surface of the rotary shaft is prevented by the presence of the first seal ring, but the inner peripheral surface of the stopper ring and the outer periphery of the rotary shaft In the case where the third seal ring is provided between the surfaces, even if the sealing function of the first seal ring is deteriorated due to aging or abrasion, the liquid to be sealed to the atmosphere side due to the presence of the third seal ring. Can be surely prevented.

  Furthermore, according to the biaxial screw pump according to the present invention, the inside-type mechanical seal having the first seal ring described above is arranged on the rotary shaft at the boundary portion between the bearing portion and the pump casing, and the rotary ring unit The liquid side wall surface and the atmosphere side wall surface of the rotary shaft or the pump screw fixed to the rotation shaft are fixed in the circumferential direction of the ring via a rotation preventing member, so that the food as the liquid to be sealed is brought to the atmosphere side. It is possible to provide a twin screw pump for sanitary use that can be handled without leaking.

It is a partial expanded side view including a partial cross section which shows the inside type mechanical seal which concerns on one Embodiment of this invention. It is a figure which shows the said mechanical seal, Comprising: (a) is AA arrow sectional drawing in FIG. 1, (b) is BB arrow sectional drawing in FIG. It is a top view including the partial cross section which shows the inside of the biaxial screw pump using the said mechanical seal. It is a side view including the partial cross section which shows the inside of the said biaxial screw pump. It is a partial expanded side view including the partial cross section which shows the inside type mechanical seal which concerns on another embodiment of this invention. It is CC sectional view taken on the line in FIG. 5 which shows the said another mechanical seal. It is a partial expanded side view including the partial cross section which shows the inside type mechanical seal which concerns on other embodiment of this invention. It is a partial expanded side view including the partial cross section which shows the conventional outside type mechanical seal. It is a partial expanded side view including the partial cross section which shows the conventional inside type | mold mechanical seal.

  Embodiments of the present invention will be described with reference to the drawings. The embodiment described below is merely an example embodying the present invention, and does not limit the technical scope of the present invention. FIG. 1 is a partially enlarged side view (including an enlarged view in a circle C) including a partial cross section showing an inside type mechanical seal according to an embodiment of the present invention, and FIG. 2 is a view showing the mechanical seal. (A) is the AA arrow directional cross-sectional view in FIG. 1, (b) has shown the BB arrow directional cross-sectional view in FIG. However, the same components as those of the conventional inside type mechanical seal shown in FIG. 9 are denoted by the same reference numerals and detailed description thereof may be omitted.

  In each figure, the inside-type mechanical seal 1 according to this embodiment is provided in a cylindrical seal housing 2 disposed outside the rotation shaft R. That is, the mechanical seal 1 includes a fixed-side sealing portion 23 provided on the seal housing 2 side and having the fixed sealing ring 3, and a rotating-side sealing portion 21 provided on the rotating shaft R side and having the rotary sealing ring 7. The contact surface pressure applying member 13 that slidably presses the rotary sealing ring 7 and the fixed sealing ring 3 is provided. The rotating shaft R is fixed to a pump screw (an example of a pump member) T of a screw pump, for example. Specifically, the rotating shaft R is inserted into a shaft hole TA formed in the pump screw T, and is fixed integrally by screwing the fixing plate 18 and the bolt 17.

  The fixed-side sealing portion 23 includes a cylindrical seat case 5 mounted in the seal housing 2, a circular ring-shaped seat ring 4 mounted in the seat case 5, and the seat case 5 and the seat ring 4. A rotation-preventing pin 6 disposed between the outer peripheral surface of the seat ring 4 and the outer peripheral surface of the seat ring 4 and the inner peripheral surface of the seal housing 2. The ring-shaped fixed sealing ring 3 is fixed to the liquid side L end face.

  The rotation-side sealing portion 21 includes a rotation ring unit 22 mounted on the rotation axis R side, and a rotation sealing ring 7 provided at the atmosphere-side V end of the rotation ring unit 22. The rotating ring unit 22 includes a stopper ring 10 attached to the rotating shaft R, a holding ring 8 attached to an end of the stopper ring 10 on the atmosphere V side so as to be movable along the ring axis S, And a second seal ring 9 that is mounted in the inner circumferential groove 8B of the holding ring 8 and interposed between the stopper ring 10 and the second ring. The second seal ring 9 is composed of, for example, an O-ring or the like, and prevents leakage of the sealed liquid J in the direction along the ring axis S. The rotary sealing ring 7 is fixed to the atmosphere-side V end surface of the holding ring 8.

  For example, three guide holes 10B, 10B, 10B and, for example, three holding holes 10C, 10C, 10C are formed on the atmosphere side V end surface of the stopper ring 10 so as to be recessed in the axis S direction. . Each holding hole 10C is loaded with a contact pressure applying member 13 made of a coil spring or the like. The atmospheric pressure side V end of each contact pressure applying member 13 is in contact with the liquid side L end surface of the inner peripheral flange 8 </ b> A formed on the inner peripheral surface of the ring of the holding ring 8. In each guide hole 10B, a drive pin 14 protruding from the liquid side L end surface of the inner peripheral flange 8A is inserted. These drive pins 14 are for guiding the movement of the retaining ring 8 relative to the stopper ring 10 in the direction of the axis S rather than in the circumferential direction.

  In the shaft hole 22A of the stopper ring 10 through which the rotation shaft R is passed, an inner circumferential groove 10A is formed on the entire inner circumferential surface 10G2 at the substantially central portion in the direction of the axis S over the entire circumference. A third seal ring 11 that seals between the inner peripheral surface 10G2 of the stopper ring 10 and the outer peripheral surface of the rotation shaft R is attached to the inner peripheral groove 10A. The third seal ring 11 is constituted by, for example, a shaft packing, and the secondary seal for reliably preventing the sealed liquid J existing in the liquid side L portion from leaking along the axis S toward the atmosphere side V. It functions as an object.

  On the inner peripheral surface 10G of the shaft hole 22A in the stopper ring 10, a hole-side step portion is formed at the boundary between the large-diameter inner peripheral surface 10G2 that is the atmosphere-side V portion and the small-diameter inner peripheral surface 10G1 that is the liquid-side L portion. 10H is formed. On the other hand, on the outer peripheral surface of the rotation shaft R at a position facing the hole side step portion 10H of the stopper ring 10, a shaft side step portion RA that is detachably engaged with the hole side step portion 10H is formed. The shaft side step portion RA of the rotation shaft R is engaged with the hole side step portion 10H of the stopper ring 10 to prevent the stopper ring 10 from moving in the direction of the fixed sealing ring 3.

  Then, at the diagonal position of the inner peripheral surface 10G1 of the stopper ring 10, for example, two locking grooves 10K and 10K extending in parallel with the axis S are formed. On the other hand, on the outer peripheral surface of the rotation shaft R at the position facing the locking grooves 10K, 10K of the stopper ring 10, locking holes RB, RB that are recessed inward in the radial direction are formed. Pin-like detent members 15 and 15 are fitted in these locking holes RB and RB. The front ends of the rotation stoppers 15 and 15 slightly protrude from the outer peripheral surface of the rotating shaft R, and these protruding portions are inserted into the locking grooves 10K and 10K of the stopper ring 10 in the direction along the axis S. It is free to move. That is, these rotation prevention members 15 and 15 fix the stopper ring 10 with respect to the rotation axis R in the ring circumferential direction. A shelf-shaped side circumferential groove 10J is formed over the entire circumference at a position radially outward from the anti-rotation member 15 on the liquid-side L front end surface of the stopper ring 10. A first seal ring 16 made of an O-ring or the like is attached to the side circumferential groove 10J. That is, the first seal ring 16 is in close contact with the side circumferential groove 10J (a part of the liquid side wall surface 10F) and the atmospheric side wall surface TC of the pump screw T. Thereby, the 1st seal ring 16 has prevented leakage of the to-be-sealed liquid J to the liquid side wall surface 10F inward rather than the side circumferential groove 10J.

  Next, the operation of the mechanical seal 1 configured as described above will be described. This mechanical seal 1 is sealed from the outer periphery, which is the liquid side L, to the inner periphery, which is the atmosphere side V, between the press-contact sliding surface 25 of the rotary sealing ring 7 and the press-contact sliding surface 25 of the fixed sealing ring 3. This is an inside type that prevents leakage of the liquid J. First, when the rotation shaft R is rotated by driving a motor (not shown), the pump screw T generates a pump force to convey the sealed liquid J, and the rotation-side sealing portion is rotated along with the rotation of the pump screw T and the rotation shaft R. 21 also rotates. At this time, the holding ring 8 of the rotating ring unit 22 is elastically pressed toward the fixed-side sealing portion 23 by the spring elastic force of the contact surface pressure applying members 13, 13, 13, and the rotating sealing ring 7 is pressed and slid. The surface 25 is slidably pressed against the pressure-contact sliding surface 25 of the fixed sealing ring 3, thereby causing a sealing action.

After the stopper ring 10 is mounted on the outer peripheral surface of the rotating shaft R from the floating end side, the rotating shaft R is mounted and fixed in the shaft hole TA of the pump screw T. On the other hand, the stopper ring 10 is elastically urged toward the atmosphere side V by the first seal ring 16 fitted in the side circumferential groove 10J, but the hole side step portion 10H contacts the shaft side step portion RA. Stop in contact. At this time, the rotation preventing member 15 indirectly fixes the rotation shaft R in the circumferential direction by fixing the stopper ring 10 to the pump screw T.
On the other hand, the non-sealing liquid J is present on the liquid side L at a position outward from the holding ring 8 and the stopper ring 10, but the non-sealing liquid J is removed from the stopper ring 10 due to the second seal ring 9. And the holding ring 8 do not enter the atmosphere side V. Further, since the first seal ring 16 is in close contact with the side circumferential groove 10J of the stopper ring 10 and the atmospheric side wall surface TC of the pump screw T, the non-sealing liquid J enters inward in the radial direction and enters the inside of the stopper ring 10. The problem of entering between the peripheral surface 10G1 and the outer peripheral surface of the rotating shaft R is prevented.

  As described above, according to the mechanical seal 1 of this embodiment, the stopper ring 10 of the rotating ring unit 22 is fixed with respect to the rotating shaft R with respect to the rotating shaft R by the rotation preventing member 15, so that there is a problem such as liquid leakage. The conventional fixing screw (reference numeral 62 in FIG. 9), which has a large number, can be omitted. Further, the first seal ring 16 is disposed between the side circumferential groove 10J of the stopper ring 10 and the atmospheric side wall surface TC of the pump member T and at a radially outward position relative to the rotation preventing member 15. Thus, the sealed liquid J can be prevented from entering the gap between the inner peripheral surface 10G1 of the stopper ring 10 and the outer peripheral surface of the rotary shaft R from between the stopper ring 10 and the pump member T. At this time, the stopper ring 10 is elastically pushed toward the atmosphere side V by the elastic force of the first seal ring 16, but the hole side step portion 10H is locked to the shaft side step portion RA of the rotating shaft R and the position thereof is reached. Can be stopped at.

  And since the 3rd seal ring 11 is arrange | positioned in the clearance gap between the internal peripheral surface 10G1 of the stopper ring 10, and the outer peripheral surface of the rotating shaft R, the 1st seal ring 16 which prevents permeation of the to-be-sealed liquid J to the clearance gap is provided. However, even when the sealing function is deteriorated due to aging or abrasion, the presence of the third seal ring 11 can surely prevent the sealed liquid J from entering the atmosphere side V.

Next, an example in which the above-described mechanical seal 1 is applied to a twin screw pump will be described with reference to FIGS.
The biaxial screw pump 31 according to this embodiment includes a cylindrical pump casing 32 penetrating in the front-rear direction and a bearing portion 5 connected to a terminal portion of the pump casing 32. On the upper surface of the pump casing 32 in the region where the pump chamber 36 is formed, an intake port 48 for taking the sealed liquid J into the pump 36 chamber is formed. A discharge-side casing 3 having a discharge port 49 is connected to the front end portion of the pump casing 32. A pair of pump screws T, T are accommodated in the pump casing 32. The base portion of each pump screw T is formed in a cylindrical shape having a shaft hole TA penetrating in the direction of the axis S. After the rotary shaft R is inserted into these shaft holes TA, a fixing plate 18 is applied to the free end of the rotary shaft R and is screwed with a bolt 17 so as to be integrally fixed to the rotary shaft R. Further, spiral screw teeth are formed on the outer peripheral surface of each base portion.

  The receiving portion 35 is formed in a box shape from a bearing casing 39 and a partition plate 40, and the cylinder end surface of the pump casing 32 is connected to the end surface of the partition plate 40 and fixed by bolts or the like. In the bearing casing 39, conical roller bearings 41, 41 and roller bearings 42, 42 are arranged. These roller bearings 41 and 42 support one end of one rotating shaft R in a cantilevered manner, and the other end of the other rotating shaft R is also supported by another conical roller bearing 41 and roller bearing 42. It is rotatably supported in a cantilever shape. That is, the bearing portion 35 is configured to rotatably support one end portions of the pair of pump screws T and T in a cantilevered manner.

  A synchronizing gear 43 is fixed to one rotating shaft R, and the other synchronizing gear 43 meshing with the synchronizing gear 43 is fixed to the other rotating shaft R. Due to the synchronous meshing of the synchronous gears 43, 43, the pair of pump screws T, T rotate so as to mesh with each other without being in contact with each other, and are not in contact with the inner peripheral surface 32A of the pump casing 32. In this case, one rotating shaft R serves as a driving shaft and is connected to the motor M via a connecting mechanism 50 such as a speed reduction mechanism. In addition, when the biaxial screw pump 31 is used for transferring foods, pharmaceuticals, cosmetic materials, etc., at least the pump as a part to which the liquid J to be sealed is in direct contact from the viewpoint of sanitary properties, that is, hygiene and property retention. It is desirable to use a stainless steel material for the casing 32, the pump screws T and T, the discharge side casing 33, and the piping.

  In the biaxial screw pump 31, the inside type mechanical seal 1 is disposed in the vicinity of the partition plate 40 that is a boundary portion between the bearing portion 35 and the pump casing 32. That is, the above-described mechanical seals 1 and 1 are respectively attached to the rotation axes R and R in the vicinity of the partition plate 40 in the bearing casing 39. In this case, the seal housing 2 of each mechanical seal 1 is fixed to the inner peripheral surface of the shaft mounting hole of the partition plate 40. Further, the stopper ring 10 in the rotating ring unit 22 and the atmospheric side wall surface TC of the pump screw T fixed to the rotating shaft R are fixed in the ring circumferential direction via the rotation preventing member 15.

  Next, the operation of the twin screw pump 31 configured as described above will be described. Examples of the high-viscosity sealed liquid J to be transferred include foods such as miso, syrup, butter and molten chocolate, cosmetics such as cream, industrial materials such as molten synthetic resin, and medical materials. First, when one pump screw T rotates in one direction by the rotational drive of the motor M, the other pump screw T to which power is transmitted via the synchronous gears 13a and 13b rotates synchronously in the reverse direction. Therefore, when the sealed liquid J is introduced into the inlet 48, the sealed liquid J is taken into the pump chamber 36. As a result, the sealed liquid J in the pump chamber 36 increases in pressure due to the pumping action of the pump screws T, T, and is sent toward the discharge-side casing 33, and is sent out from the discharge port 19 vigorously. In this case, the sealed liquid J whose pressure has increased reaches the liquid side L of each mechanical seal 1, but due to the presence of the first seal ring 16, the outer peripheral surface of the inner peripheral surface 10 </ b> G <b> 1 of the stopper ring 10 and the rotation shaft R. It cannot penetrate between the surfaces.

  As described above, according to the biaxial screw pump 31 of this embodiment, the inside mechanical seal 1 having the first seal ring 16 is attached to the rotational axis R at the boundary between the bearing portion 35 and the pump casing 32. Since the liquid side L of the stopper ring 10 and the rotating shaft R are fixed in the circumferential direction of the ring via the anti-rotation member 15, the food as the liquid to be sealed J is reliably transferred to the atmosphere side V. We were able to provide a pump that could be handled without leaking. In addition, since the pump screws T and T and the inner peripheral surface 32A of the pump casing 32 are not in contact with each other, no metal abrasion powder is generated, and no shear force is applied to the sealed liquid J and the quality is not changed. That is, it is possible to provide a highly sanitary pump suitable for transferring food, medical products, and the like.

In the above embodiment, the side circumferential groove 10J is formed on the liquid side wall surface 10F of the stopper ring 10, the first seal ring 16 is attached to the side circumferential groove 10J, and the inner side of the liquid side L of the stopper ring 10 is further increased. While the engaging grooves 10K and 10K are formed on the peripheral surface 10G1, the engaging hole RB is formed on the rotation shaft R, and the mechanical seal 1 in which the anti-rotation member 15 is fitted in the engaging hole RB is illustrated. However, the present invention is not limited to this.
For example, as shown in FIGS. 5 and 6 including an enlarged view in a circle D, a mechanical seal 1a in which a rotation preventing member 15a is attached to the liquid side wall surface 10F of the stopper ring 10a is also included in the present invention. In this mechanical seal 1a, in the shaft hole 22A in the stopper ring 10a, a hole-side step is formed at the boundary between the large-diameter inner peripheral surface 10G2 that is the atmosphere-side V portion and the small-diameter inner peripheral surface 10G1 that is the liquid-side L portion. Part 10Ha is formed. On the other hand, on the outer peripheral surface of the rotation shaft R at a position facing the hole side step portion 10Ha of the stopper ring 10a, a shaft side step portion RAa that is detachably engaged with the hole side step portion 10Ha is formed.

  On the other hand, for example, two locking holes 10D and 10D are formed at the diagonal position of the tip end surface of the liquid side L in the stopper ring 10a. Pin-like detent members 15a and 15a are fixed to these locking holes 10D and 10D. The non-rotating members 15a and 15a are loosely fitted freely into and out of engaging holes TB and TB formed in the atmospheric side wall surface TC of a pump screw (an example of a pump member) T fixed to the rotary shaft R with a bolt 17 or the like. It is charged in the shape. That is, these rotation prevention members 15a and 15a fix the stopper ring 10a in the ring circumferential direction with respect to the rotation axis R. A shelf-shaped ring receiving surface 10E is formed over the entire circumference of the stopper ring 10a at a position radially outward from the anti-rotation member 15a at the liquid-side L front end surface. A first seal ring 16 made of an O-ring or the like is attached to the ring receiving surface 10E. That is, the first seal ring 16 is in close contact with the ring receiving surface 10E, the liquid side wall surface 10F of the stopper ring 10a connected to the ring receiving surface 10E, and the atmospheric side wall surface TC of the pump screw T. Thus, the first seal ring 16 prevents the sealed liquid J from leaking inward in the ring radial direction.

  Also with the mechanical seal 1a having the above-described configuration, the stopper ring 10a can be fixed with respect to the rotation axis R in the circumferential direction of the ring not by the conventional fixing screw but by the anti-rotation member 15a. Further, the provision of the first seal ring 16 can prevent the sealed liquid J from entering the gap between the inner peripheral surface 10G1 of the stopper ring 10a and the outer peripheral surface of the rotation shaft R.

In the above description, the rotary ring unit 22 is illustrated as being divided into the stopper rings 10 and 10a and the holding ring 8 and the second seal ring 9 and the contact pressure applying member 13 interposed therebetween. Is not limited to them.
For example, a mechanical seal 1b as shown in FIG. 7 is also included in the present invention. The mechanical seal 1b in FIG. 7 differs from the structure of the mechanical seal 1 (FIGS. 1 and 2) described above in that the rotating ring unit is divided into a stopper ring 10b and a holding ring 8b, and a stopper ring. The absence of the inner peripheral groove 10A, the guide hole 10B, the holding hole 10C and the second seal ring 9 of 10b, and the third seal ring 11a being mounted in the inner peripheral groove formed in the holding ring 8b. That is, a large-diameter coil ring-shaped contact surface pressure applying member 13a surrounding the outer periphery of the stopper ring 10b and the holding ring 8b is provided in place of the three contact surface pressure applying members 13, 13, and 13.
Even in the mechanical seal 1b having such a contact surface pressure applying member 13a, the stopper ring 10b can be fixed with respect to the rotation axis R in the ring circumferential direction. Needless to say, it can be prevented from entering between the inner peripheral surface 10G1 of the stopper ring 10b and the outer peripheral surface of the rotary shaft R.

  In the above description, the rotating ring unit 22 is divided into the stopper ring 10, 10a and the holding ring 8 as an inside type mechanical seal, and the second seal ring 9 and the contact pressure applying member 13 are interposed therebetween. However, the present invention is not limited thereto. For example, the rotating ring unit is configured as a single unit and attached to the rotating shaft, and the seat ring of the fixed-side sealing portion is divided into two members and a contact pressure applying member is interposed between them. Are also included in the present invention. Further, as the contact surface pressure applying member, instead of the plurality of coil springs (13) used for the stopper rings 10 and 10a and the large-diameter coil spring (13a) used for the stopper ring 10b, for example, a torsion ring spring Others can also be used.

  And although the example which applied mechanical seal 1,1a, 1b to the biaxial screw pump was shown above, the mechanical seal of this invention is not limited to it. For example, a pump suitable for food hygiene such as a vane pump and a mono pump can be preferably applied.

  The present invention is not limited to the above-described embodiment, and departs from the gist of the present invention including various modifications and corrections that can be conceived by those having ordinary knowledge in the field of the present invention. Of course, even if there is a design change within a range not to be included, it is included in the present invention.

1, 1a, 1b Mechanical seal 2 Seal housing 3 Fixed seal ring 7 Rotating seal ring 8 Holding ring 9 Second seal ring 10, 10a, 10b Stopper ring 10D Locking hole 10E Ring receiving surface 10F Liquid side wall surface 10G, 10G1, 10G2 Inner peripheral surface 10H, 10Ha Hole side step 10J Side peripheral groove (liquid side wall surface)
10K Locking groove 11, 11a Third seal ring 13, 13a Contact surface pressure applying member 15 Non-rotating member 16 First seal ring 21 Rotating side sealing portion 22 Rotating ring unit 22A Shaft hole 23 Fixed side sealing portion 25 Pressing sliding surface 31 Biaxial screw pump 32 Pump casing 35 Bearing portion 36 Pump chamber 40 Partition plate 48 Inlet 49 Discharge port J Sealed liquid L Liquid side S Shaft center T Pump screw (pump member)
TB engagement hole TC atmosphere side wall surface R rotation axis RA, RAa shaft side step RB engagement hole V atmosphere side

Claims (4)

A rotating ring unit having a rotating ring unit mounted on the rotating shaft side and a rotating sealing ring held by the rotating ring unit; a fixed sealing unit disposed on a seal housing; the rotating sealing ring; A contact surface pressure applying member that slidably presses the fixed sealing ring of the fixed-side sealing portion in a slidable manner, from the outer periphery to the inner peripheral direction of the pressure contact sliding surface of the rotary sealing ring and the fixed sealing ring An inside type mechanical seal designed to prevent leakage of liquid to be sealed,
Between the liquid side wall surface of the rotating ring unit and the atmospheric side wall surface of the pump shaft fixed to the rotating shaft or the rotating shaft, the rotating ring unit is fixed to the rotating shaft in the ring circumferential direction. A stop member is provided, and is between the liquid side wall surface of the rotary ring unit and the atmospheric side wall surface of the rotary shaft or the pump member fixed to the rotary shaft, and is located radially outward from the rotation stop member. In addition, a first seal ring that prevents leakage of liquid to be sealed radially inward is provided, and the atmosphere side portion has a large diameter on the inner peripheral surface of the shaft hole through which the rotation shaft of the rotation ring unit passes. A hole-side step portion having a small diameter on the liquid side portion is formed, and a shaft-side step portion that engages with the hole-side step portion of the rotating ring unit and prevents the rotating ring unit from moving in the fixed sealing ring direction. The rotation Mechanical seal, characterized in that formed on the outer circumferential surface of the. The rotating ring unit includes a stopper ring mounted on a rotating shaft, a holding ring that is mounted on the atmosphere side end of the stopper ring so as to be movable in the ring axis direction, and holds the rotating sealing ring, and the stopper The second contact ring that is interposed between a ring and the holding ring to prevent leakage of a liquid to be sealed in a ring axial direction, and the contact surface pressure applying member. mechanical seal. Between the outer peripheral surface of the rotary shaft and the inner peripheral surface of the shaft hole formed in the stopper ring, 請 Motomeko 2 third seal ring to prevent leakage in the axial direction of the sealed liquid that is deployed The mechanical seal as described in. A pair of pump screws that rotate in a non-contact threaded manner, a pump casing that accommodates the pair of pump screws in a non-contact manner and forms a pump chamber between the pair of pump screws, and the pump casing. A bearing portion that is connected and rotatably supports one end portion of the pair of pump screws in a cantilevered manner, and a pump casing in a region where the pump chamber is formed is configured to introduce a liquid to be sealed into the pump chamber. The pump casing on the floating end side of the pair of pump screws is provided with a discharge port for discharging the sealed liquid transferred from the pump chamber, and is taken into the pump chamber from the intake port. In the biaxial screw pump that transfers the sealed liquid by the rotational drive of a pair of pump screws and discharges it from the discharge port.
The mechanical seal according to any one of claims 1 to 3 is disposed at a boundary portion between the bearing portion and the pump casing, and a liquid side wall surface of a rotating ring unit of the mechanical seal; A biaxial screw pump, wherein the rotary shaft or an atmospheric side wall surface of a pump screw fixed to the rotary shaft is fixed in a ring circumferential direction via the rotation preventing member.

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