JPH0942180A - Sealing method for rotary displacement type pump and the pump itself - Google Patents

Abstract

PROBLEM TO BE SOLVED: To minimize the leakage of fluid according to necessity for finely regulating the quantity of leakage by making the fluid temporarily stay in a ring-shaped space to cool it with a refrigerant in a cooling jacket for turning it into a semisolid solution. SOLUTION: When a shaft 3 rotates, a bush 10 rotates with the shaft 3. Molten resin passes through a gap between the shaft 3 and a bearing 4 from a case 1 and enters a space V. On the other hand, since a seal ring 20 is cooled with a refrigerant in a cooling jacket 23, the molten resin in the space V coming into contact with the seal ring 20 is cooled and solidified to proper hardness to turn into a ring-shape. In this case, since temperature is detected by a thermometer 8, and a cooling water fed to the cooling jacket 23 is adjusted, and the temperature of the seal ring 20 is therefore adjusted to the proper temperature, a resin reservoir formed of the space V always locks a similar semisolid solution ring to carry out sealing action.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to rotary positive displacement pumps such as gear pumps and screw pumps.

[0002]

2. Description of the Related Art Since a gear pump for plastic extrusion is exposed to high temperature and high pressure as compared with a general pump, a mechanical seal, a gland packing or the like is rarely used for its shaft. The most frequently used sealing method is
A fine spiral groove is provided on the inner surface of the seal ring, and the rotation of the shaft causes the spiral groove to flow back the leaked liquid from the outside to the inside, thereby reducing the amount of leakage from the pump.

Further, the cooling jacket lowers the temperature in the vicinity of the shaft, solidifies the leaked molten resin to a certain extent, and has a function of suppressing the leak amount.

Further, FIG. 6 shows a structure in which a gap G between the seal rings A and B facing each other in the axial direction can be adjusted during operation by an external adjusting screw C.

[0005]

However, these conventional techniques have the following problems. That is, in the method in which the gap between the shaft and the seal ring is fixed, the leakage of the resin from the gap changes depending on the operating conditions of the pump, such as temperature, pressure, and rotation speed. To adjust this, the pump must be stopped and the leak adjusted by modifying or replacing the seal ring.

Further, in the method of solidifying the resin in the gap with the cooling jacket, the volume of the gap becomes very small.
A slight change in temperature causes the resin in the gap to become unstable, causing the resin to adhere to the shaft or increase leakage. In addition, since there is no method for measuring the temperature of the gap, there is no recording or reproducibility since the temperature control by the cooling jacket is performed only by visually checking the state of the resin in the gap.

On the other hand, in the method of adjusting the clearance by moving the seal ring with the adjusting screw, the amount of resin leakage is controlled only by the size of the axial clearance G between the seal rings A and B. Contact (when the gap is too small) or large leakage (when the gap is large)
It is easy to become.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to provide a method for sealing a rotary positive displacement pump and a rotary positive displacement pump in which fluid leakage can be minimized and the amount of leakage can be finely adjusted.

[0009]

In order to solve the above problems, the structure of the present invention is as follows. That is, according to the method of the first configuration, in the rotary positive displacement pump in which the rotating body is rotatably supported in the case through the shaft and the bearing, and the side plate is fixed to the case through the shaft, the bush is concentric with the shaft. Is inserted and fixed to leave a slight gap between the bearing and the side plate through hole, and the seal ring is inserted into the shaft so as to face the bush in the axial direction with a slight gap left between the side plate and the side plate. Is slidably fitted in the hole of the bushing and overlaps with the bush in a part of the axial direction, and the seal ring is moved in the axial direction, and one side and / or the other side in the axial direction of the overlapping portion. , A ring-shaped space larger than the gap of the overlapping portion is formed, the fluid is temporarily retained in the space to cool, and the temperature of the fluid in the space is detected to detect the temperature of the seal ring cooling jacket. Adjust the cooling medium volume and / or Adjusts the axial position of the seal ring, the fluid in the space is to a semi-solid solution form.

The method of the second configuration is that, in addition to the first configuration, the overlapping surface of the bush and the seal ring is a tapered surface.

According to the third structure, in a rotary positive displacement pump in which a rotating body is rotatably supported in a case via a shaft and a bearing, and a side plate is fixed to the case through the shaft, the rotary plate is concentrically fixed to the shaft. And a bush interposed between the side plate through hole and the side plate through hole, and axially opposed to the bush and inserted through the shaft with a gap, and slidable in the hole of the side plate. A seal ring that is fitted and has a flange portion formed on the outside of a cylindrical portion that overlaps with the bush in a portion in the axial direction; and an adjusting means that moves and fixes the seal ring in the axial direction, A gap is left in the overlapping portion between the bush and the seal ring, and a ring-shaped space larger than the gap in the overlapping portion is left inside and / or outside in the axial direction.

According to a fourth structure, in a rotary positive displacement pump in which a rotating body is rotatably supported in a case via a shaft and a bearing and a side plate is fixed to the case through the shaft, the rotary body is concentrically fixed to the shaft. And a bush formed with an outer taper cylindrical portion that is interposed between the side plate through hole and the side plate through hole and is tapered outward in the axial direction, and a gap is formed in the shaft so as to face the bush in the axial direction. A seal ring that is inserted into the inner side of the bush and is slidably fitted in the hole of the side plate, and a flange is formed on the outer side of the inner tapered barrel that overlaps with the outer tapered barrel of the bush. And an adjusting means for axially moving and fixing the same, a gap is left in the overlapping portion between the bush and the seal ring, and a ring-shaped space that is larger than the gap in the overlapping portion is axially inside thereof. It is left.

According to the fifth structure, in a rotary positive displacement pump in which a rotating body is rotatably supported in a case via a shaft and a bearing, and a side plate is fixed to the case through the shaft, the rotary body is concentrically fixed to the shaft. And a bush formed with an outer taper cylindrical portion that is interposed between the side plate through hole and the side plate through hole and is tapered outward in the axial direction, and a gap is formed in the shaft so as to face the bush in the axial direction. A seal ring that is inserted into the inner side of the bush and is slidably fitted in the hole of the side plate, and a flange is formed on the outer side of the inner tapered barrel that overlaps with the outer tapered barrel of the bush. And an adjusting means for axially moving and fixing the same, a gap is left in the overlapping portion between the bush and the seal ring, and a ring-shaped space larger than the gap in the overlapping portion is axially outside of the overlapping portion. It is left.

A sixth structure is a rotary positive displacement pump in which a rotating body is rotatably supported in a case via a shaft and a bearing, and a side plate is fixed to the case through the shaft, and is fixed concentrically to the shaft. And a bush formed with an inner taper tube portion that is narrowed inward in the axial direction and is interposed between the side plate through hole and the side plate through hole, and a gap is formed in the shaft so as to face the bush in the axial direction. A seal ring that is inserted into the bush, is slidably fitted in the hole of the side plate, and has a flange portion formed outside the outer tapered cylindrical portion that overlaps with the inner tapered cylindrical portion of the bush. And an adjusting means for axially moving and fixing the same, a gap is left in the overlapping portion between the bush and the seal ring, and a ring-shaped space that is larger than the gap in the overlapping portion is axially inside thereof. It is left.

The seventh structure is a rotary positive displacement pump in which a rotating body is rotatably supported in a case via a shaft and a bearing, and a side plate is fixed to the case through the shaft, and is fixed concentrically to the shaft. And a bush formed with an inner taper tube portion that is narrowed inward in the axial direction and is interposed between the side plate through hole and the side plate through hole, and a gap is formed in the shaft so as to face the bush in the axial direction. A seal ring that is inserted into the bush, is slidably fitted in the hole of the side plate, and has a flange portion formed outside the outer tapered cylindrical portion that overlaps with the inner tapered cylindrical portion of the bush. And an adjusting means for axially moving and fixing the same, a gap is left in the overlapping portion between the bush and the seal ring, and a ring-shaped space larger than the gap in the overlapping portion is axially outside of the overlapping portion. It is left.

In the eighth structure, in addition to any one of the third to seventh structures, a measurement hole is provided from the outer peripheral surface of the side plate toward the ring-shaped space, and a thermometer is inserted into the measurement hole. That is, the seal ring is provided with a cooling jacket.

[0017]

When the shaft is rotated, the bush rotates with the shaft. The molten resin enters the space V from the case through the gap between the shaft and the bearing. On the other hand, since the seal ring is cooled by the cooling medium of the cooling jacket, the molten resin in the space V that touches the seal ring is cooled and solidified to have an appropriate hardness to form a ring shape, and the sealing ring itself functions as a packing material. Also,
Since the bush and the seal ring form a taper-shaped gap, the taper gap change amount becomes smaller with respect to the axial movement amount of the seal ring by the operation of the adjusting means, and the gap can be finely adjusted.

Some leakage from the resin ring of the semi-solid solution is released to the outside from around the shaft. The temperature of the resin ring is adjusted to an appropriate temperature by detecting the temperature with a thermometer and adjusting the cooling medium to the cooling jacket.
, Always forms a similar semi-solid solution ring to provide a sealing effect.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below based on an embodiment of a gear pump shown in the drawings. In FIG. 1, a gear 2 is rotatably supported in a case 1 via a shaft 3 and a bearing 4, and a side plate 5 is fixed to the case 1 through the shaft 3.

The bush 10 is inserted through the shaft 3 and fixed concentrically, and is interposed between the bush 10 and the through hole 5a of the side plate 5 with a gap. The bush 10 is concentrically located outside the cylindrical portion 11 (in the axial direction toward the outside of the pump).
Are formed via the step portion 13. The outer circumferential surface of the outer taper cylinder portion 12 becomes a taper surface 12a which is tapered outward in the axial direction.
Further, it has a central hole 10a through which the shaft 3 penetrates at the axial center. Then, it is fixed to the shaft 3 by a set screw 6 penetrating in the radial direction from the outer circumferential surface of the cylindrical portion 11.

A seal ring 20 is inserted through the shaft 3 so as to face the bush 10 in the axial direction, with a gap,
And it is slidably fitted in the through hole 5a of the side plate 5. The seal ring 20 has a flange portion 22 formed on the outer side in the axial direction of an inner tapered cylindrical portion 21 overlapping the outer tapered cylindrical portion 12 of the bush. The inner circumferential surface of the inner tapered cylindrical portion 21 is a tapered surface 21a which is tapered outward in the axial direction so as to match the outer tapered surface 21a, and the stepped portion 2
A central hole 20a through which the shaft 3 penetrates is provided at the center of the shaft.
Further, the seal ring 20 is provided with a cooling jacket 23 through which cooling water passes. A plurality of screw rods 7 serving as adjusting means for moving and fixing the seal ring 20 in the axial direction are attached to the shaft 3
Are equally spaced on the same circumference with the center as the center and penetrate through the flange portion 22 of the seal ring and are screwed into the side plate 5.

Then, as shown in FIG. 2, a gap G ₁ and a side plate through hole 5 are provided between the bush cylindrical portion 11 and the bearing 4.
A gap G ₂ is left between it and a. Also, the tapered surface 1
The ring-shaped space V (shaft) is formed on the axially inner side of the overlapping portion of 2a and 21a in a portion surrounded by the end faces of the bush outer taper cylinder part 12 and the seal ring inner taper cylinder part 21 and the side plate through hole 5a. Directional clearance G ₃₁ , radial clearance G
₃₂ ) is left. Further, a gap G _{4 is provided} between the tapered surfaces of the outer and inner tapered tubular portions 12 and 21, a gap G ₅ is provided between the end surface of the outer tapered tubular portion 21 and the surface of the step portion 24 of the inner tapered tubular portion 21, the seal ring. A slight gap G ₆ is left between the inner surface of the central hole 10a and the shaft 3.

A measuring hole 5b is provided from the outer peripheral surface of the side plate 5 toward the ring-shaped space V, and a thermometer 8 is inserted into the measuring hole.

The operation state will be described above. When the shaft 3 is rotated, the bush 10 rotates together with the shaft 3. The molten resin passes through the gap between the shaft 3 and the bearing 4 from the case 1,
Further, it enters the space V through the gaps G ₁ and G ₂ . on the other hand,
Since the seal ring 20 is cooled by the cooling medium (water, oil, air, etc.) of the cooling jacket 22, the molten resin in the space V that touches the seal ring 20 is cooled and solidified to have an appropriate hardness, and becomes a ring shape. Acts as a packing material. That is, if leaked fluid from the gear side enters the semi-solid solution ring, it does not immediately exit. Due to the elasticity of the ring, the entry of leakage from the high pressure side causes the ring to be compressed and pressed against the outflow side to perform a sealing function. If the pressure rises to some extent, the leak will go out of the ring. In this way, it serves as a packing.

Further, since the bush 10 and the seal ring 20 form a tapered gap G ₄ , by operating the adjusting screw 7, the amount of change in the gap distance with respect to the axial movement of the seal ring becomes small, and Can be finely adjusted.

A slight leak from the resin ring of the semi-solid solution is discharged to the outside through the gaps G ₄ , G ₅ and G ₆ . The temperature of the resin ring is adjusted to an appropriate temperature by detecting the temperature with the thermometer 8 and adjusting the cooling water to the cooling jacket 23, and the resin pool due to the ring-shaped space V is always the same ring of semi-solid solution. To form a seal.

FIG. 3 shows a second embodiment, in which, in addition to the ring-shaped space V, the second space V ₂ is also axially outward, the end surface of the bush outer taper cylinder portion 12 and the seal ring inner taper surface 21.
a. This significantly increases the sealing effect. Alternatively, only the second space V ₂ may be provided by eliminating the space V and forming a slight gap.

FIG. 4 shows a third embodiment in which the tapered surfaces of the bush 10 and the seal ring 20 are tapered inward in the axial direction opposite to the above. That is, the bush 10 is provided with an inner taper cylinder portion that becomes thinner in the axial direction. In addition, the seal ring 20 is provided with an outer tapered cylindrical portion that overlaps with the inner tapered cylindrical portion. Then, a ring-shaped space V is left between the end surface of the inner taper tube portion of the bush and the outer taper tube portion of the seal ring outside the tapered surface overlapping portion in the axial direction.

FIG. 5 shows a fourth embodiment, and in the third embodiment, the ring-shaped space V is axially inward of the tapered surface overlapping portion, that is, the bush inner taper cylinder portion and the seal ring outer taper cylinder end surface. It is located between and. Alternatively, the spaces V may be provided at two locations by combining the third and fourth embodiments.

The overlapping portion between the bush 10 and the seal ring 20 may be a cylindrical surface having a constant diameter instead of the above-mentioned tapered surface, that is, a cylindrical surface of which the diameter changes. In this case, the amount of leakage is adjusted by adjusting the size of the ring-shaped space V and adjusting the flow rate of cooling water to the cooling jacket.

Numerical examples of the ring-shaped space V and the gaps between the respective parts are shown in Table 1.
It is as follows.

Therefore, the size of the space V is G ₃₁ = 3 to 2
5 mm and G ₃₂ = 3 to 25 mm are suitable, and among them, G ₃₁ = 5 to 15 mm and G ₃₂ = 5 to 15 mm are more suitable.

The present invention is applied to rotary positive-displacement pumps such as gear pumps, screw pumps, vane pumps and cam pumps, and also melted plastics, rubbers, paints, waxes,
Suitable for various fluids of large viscosity such as adhesives.

The present invention is not limited to the examples and embodiments described above, but includes various modifications without departing from the spirit and scope of the claims.

[0035]

According to the structure of the present invention, the resin pool V can be controlled by monitoring the thermometer and adjusting the amount of the cooling medium to the cooling jacket.
It is possible to make a suitable semi-solid solution by using the resin of this part as a packing while keeping the temperature constant. Therefore, the adjustment of the gaps G _{4 to} G ₆ does not need to be so delicate. When the overlapping portion between the seal ring and the bush has a tapered surface, the gap in the tapered surface can be finely adjusted by moving the seal ring in the axial direction.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a gap near an axis.

FIG. 3 is a vertical sectional view of an essential part of a second embodiment of the present invention.

FIG. 4 is a vertical sectional view of an essential part of a third embodiment of the present invention.

FIG. 5 is a vertical sectional view of an essential part of a fourth embodiment of the present invention.

FIG. 6 is a vertical sectional view of a conventional technique.

[Explanation of symbols]

 G Gap V Space 1 Case 2 Gear 3 Shaft 4 Bearing 5 Side plate 5a Through hole 5b Measuring hole 6 Set screw 7 Adjusting screw 8 Thermometer 10 Bushing 10a Center hole 11 Cylindrical part 12 Outer taper tube part 13 Step part 20 Seal ring 20a Center Hole 21 Inner taper cylinder 22 Flange 23 Cooling jacket 24 Step

[Table 1]

Claims (8)

[Claims] 1. A rotary positive displacement pump in which a rotating body is rotatably supported in a case via a shaft and a bearing, and a side plate is fixed to the case through the shaft, wherein a bush is inserted and fixed concentrically with the shaft. A small gap is left between the bearing and the side plate through hole, and a seal ring is inserted axially opposite the bush in the shaft with a slight gap left between the bearing and the side plate through hole. It is movably fitted, and is superposed on the bush in a part in the axial direction, and the seal ring is moved in the axial direction, and the superposition is applied to one side and / or the other side in the axial direction of the overlapping portion. A ring-shaped space larger than the gap between the parts is formed, the fluid is temporarily retained in the space to cool, and the temperature of the fluid in the space is detected to determine the amount of the cooling medium in the cooling jacket of the seal ring. Adjust and / or A method for sealing a rotary positive-displacement pump, wherein the axial position of a ring is adjusted so that the fluid in the space is in a semi-solid solution state. 2. The method of sealing a rotary positive displacement pump according to claim 1, wherein the overlapping surface of the bush and the seal ring is a tapered surface. 3. A rotary positive displacement pump in which a rotating body is rotatably supported in a case via a shaft and a bearing, and a side plate is fixed to the case through the shaft, wherein the side plate is concentrically fixed to the shaft. A bush interposed with a gap between the through hole and the bush, which is axially opposed to the bush and is inserted into the shaft with a gap, and is slidably fitted in the hole of the side plate. A bush including a seal ring having a flange portion formed on the outer side of a cylindrical portion that overlaps with the bush in a portion in the axial direction; and an adjusting unit that moves and fixes the seal ring in the axial direction. A gap is left in the overlapping portion with the seal ring, and is axially inside and / or outside,
A rotary positive-displacement pump, wherein a ring-shaped space larger than the gap of the overlapping portion is left. 4. A rotary positive displacement pump in which a rotating body is rotatably supported in a case through a shaft and a bearing, and a side plate is fixed to the case through the shaft, wherein the side plate is concentrically fixed to the shaft. A bush, which is interposed between the through hole and a gap and has an outer taper cylinder portion which is tapered outward in the axial direction, and a bush which faces the bush in the axial direction and has a gap in the shaft. A seal ring which is inserted, slidably fitted in the hole of the side plate, and formed with a flange portion on the outer side of the inner tapered cylindrical portion which overlaps with the outer tapered cylindrical portion of the bush; A gap is left in the overlapped portion between the bush and the seal ring, and a ring-shaped space larger than the gap in the overlapped portion is left inside in the axial direction thereof. Rotation characterized by Product pump. 5. A rotary positive displacement pump in which a rotating body is rotatably supported in a case through a shaft and a bearing, and a side plate is fixed to the case through the shaft, wherein the side plate is concentrically fixed to the shaft. A bush, which is interposed between the through hole and a gap and has an outer taper cylinder portion which is tapered outward in the axial direction, and a bush which faces the bush in the axial direction and has a gap in the shaft. A seal ring which is inserted, slidably fitted in the hole of the side plate, and formed with a flange portion on the outer side of the inner tapered cylindrical portion which overlaps with the outer tapered cylindrical portion of the bush; A gap is left in the overlapping portion between the bush and the seal ring, and a ring-shaped space larger than the gap in the overlapping portion is left outside in the axial direction thereof. Rotation characterized by Product pump. 6. A rotary positive displacement pump in which a rotating body is rotatably supported in a case via a shaft and a bearing, and a side plate is fixed to the case through the shaft, wherein the side plate is concentrically fixed to the shaft. A bush which is interposed between the through hole and a gap and has an inner taper cylindrical portion which is tapered inward in the axial direction, and a gap which is axially opposed to the bush and is formed in the shaft. A seal ring which is inserted, slidably fitted in the hole of the side plate, and formed with a flange portion on the outer side of the outer tapered cylindrical portion which overlaps with the inner tapered cylindrical portion of the bush; A gap is left in the overlapped portion between the bush and the seal ring, and a ring-shaped space larger than the gap in the overlapped portion is left inside in the axial direction thereof. Rotation characterized by Product pump. 7. A rotary positive displacement pump in which a rotating body is rotatably supported in a case through a shaft and a bearing, and a side plate is fixed to the case through the shaft, wherein the side plate is concentrically fixed to the shaft. A bush which is interposed between the through hole and a gap and has an inner taper cylindrical portion which is tapered inward in the axial direction, and a gap which is axially opposed to the bush and is formed in the shaft. A seal ring which is inserted, slidably fitted in the hole of the side plate, and formed with a flange portion on the outer side of the outer tapered cylindrical portion which overlaps with the inner tapered cylindrical portion of the bush; A gap is left in the overlapping portion between the bush and the seal ring, and a ring-shaped space larger than the gap in the overlapping portion is left outside in the axial direction thereof. Rotation characterized by Product pump. 8. A measuring hole is provided from an outer peripheral surface of the side plate toward the ring-shaped space, a thermometer is inserted into the measuring hole, and a cooling jacket is provided at the seal ring. The rotary positive displacement pump according to any one of claims 3 to 7.