JPH07279857A - Shaft seal device in pump for feeding fused plastic material - Google Patents

Abstract

PURPOSE:To cool a fused plastic material leaking through a grand packing with no affection upon a pump body so as to safely solidify a fused plastic material. CONSTITUTION:In a shaft seal device 1, a packing retainer 9 located laterally of a packing box 3, is composed of a cylindrical part 9a abutting against a grand packing loosely fitted on a shaft 3, a body 9b integrally incorporated with a body 9b, and a bolt 10 and a nut 11 screwed onto the nut 11, by which the degree of fastening the grand packing 4 can be adjusted. An annular jacket chamber 13 is formed in the body 9b, surrounding around a gap between the body 9b and the shaft 3. An accumulating chamber 16 communicated with the gap 12, and a discharge port 17 communicated with the accumulating chamber 16 and opened downward, are formed in the body 9b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention interposes a gland packing between a packing box of a main body casing and a main shaft which penetrates the packing box and projects to the outside, and tightens and seals the gland packing with a packing retainer. The present invention relates to a shaft seal device for a pump.

[0002]

2. Description of the Related Art A gland packing is the most commonly used sealing means in a pump shaft sealing device. FIG. 4 is an explanatory view showing a conventional shaft sealing device 20 of a pump, in which a main shaft 22 is passed through a packing box 21 integrally provided with a main body casing, and a gland packing 23 is provided between the packing box 21 and the main shaft 22. Further, on the atmosphere side (right side) of the packing box 21, a packing presser 24 that is loosely inserted into the main shaft 22 is screwed by a bolt 25 and a nut 26 fixed to the packing box 21, and the gland packing 23 is tightened by the packing presser 24. In addition, the contact pressure is generated in the packing to limit leakage. However, when such a gland packing 23 is used, if the leakage amount is reduced to 0, lubrication between the gland packing 23 and the main shaft 22 deteriorates, frictional heat is generated, and the life is shortened. It is necessary to adjust the tightening amount of 24 to allow a small amount of leakage between the gland packing 23 and the main shaft 22 to ensure lubricity. However, the transferred fluid is at a high temperature (about 3
Flammability, like molten plastic at 0-450 ° C,
If it is highly ignitable, it is dangerous to let it leak as it is. Therefore, as shown in the figure, an annular jacket chamber 27 is provided in the packing box 21 around the gland packing 23.
Pass steam (about 100-140 ° C) lower than fluid temperature, cooling water (normal temperature), etc. (about 100 per minute with steam)
˜1000 N liters, about 10 to 100 liters per minute with cooling water), the high temperature fluid was indirectly cooled after being ignited and then leaked, and then discharged from between the main shaft 22 and the packing retainer 24. .

[0003]

In the above-mentioned conventional shaft sealing device, since the solidification temperature of the molten plastic in the thermal decomposition process is about 80 to 150 ° C., it leaks in liquid form between the main shaft and the packing retainer. The plastic in the process of decomposition is
Steam cooling reaches about 150 to 250 ° C., there is still a risk of ignition, and there is a high risk of burns for the operator. Therefore, a method has been adopted in which cooling water is caused to flow into the jacket chamber instead of steam to enhance the cooling effect. In this case, the cooling effect of the packing box increases and the molten plastic solidifies while leaking between the gland packing and the main shaft, and can be taken out as a solidified plastic decomposition product, so there is no danger of ignition and it is safe. However, conversely, the lubricity between the gland packing and the main shaft deteriorates, which shortens the service life of both. Also, since a large amount of cooling water is used,
While the molten plastic in the pump body is also cooled, the thermal efficiency deteriorates, and also in the pump body, the thermal gradient between the packing box and other components that become low in temperature becomes large.
The thermal stress of the pump components is also great and the life of the constituent materials is shortened. In addition, the temperature gradient may cause deformation of the pump.

[0004]

Therefore, according to the present invention, it is possible to not only safely solidify and discharge the molten plastic at high temperature but also to recover and reuse the molten plastic.
Furthermore, the cooling action provides a shaft seal device for the pump that does not affect the lubrication between the gland packing and the main shaft or the components of the pump.The structure is such that the jacket chamber does not contact the main shaft with the packing retainer. Specifically, the jacket chamber is built in the packing presser or is detachably provided separately from the packing presser. Further, the packing retainer may be provided with a leakage material discharge passage communicating with a gap between the main shaft and the packing retainer. In addition, the main shaft in the present invention means, of course, a single shaft,
It also includes a form of a shaft sleeve in which a sleeve is externally mounted on the shaft and sealed with a gland packing.

[0005]

[Function] When cooling water or the like is injected into the jacket chamber, the packing retainer is cooled by the cooling action, and the molten plastic leaking from between the gland packing and the main spindle is cooled between the seal retainer and the main spindle to form solidified plastic. Is discharged. Therefore, not only can the solidified plastic be safely taken out, but also its recovery can be done easily. The lubricity between the main shaft and the gland packing is not lost, and the cooling action of the packing retainer does not affect the pump body. If the jacket chamber is built in the packing holder, a high cooling effect can be achieved, which is a preferable form. On the other hand, if it is detachable as a separate body, it can be applied to an existing shaft sealing device, and a special effect can be obtained. Further, if a discharge passage is provided in the packing retainer, the solidified plastic does not scatter, and the collection of the plastic becomes easy, which facilitates reuse in the raw material tank.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory diagram showing the details of a shaft sealing device 1 in a gear pump for a thermal decomposition oil reduction plant for waste plastic that transfers molten plastic in a high temperature decomposition process, the right side is the atmosphere side, and the left is the pump body side. is there. A shaft 3 penetrates through the center of the packing box 2 integrated with the pump body, and a gland packing 4 is provided between the shaft 3 and the packing box 2 to seal the two. An annular first jacket chamber 5 is formed outside the gland packing 4 in the packing box 2, and the cooling steam supplied from the inlet 6 is discharged from the outlet 7 through the first jacket chamber 5. The molten plastic 8 leaking between the shaft 3 and the gland packing 4 can be indirectly cooled to a temperature lower than the ignition point. A packing retainer 9 is arranged on the side of the packing box 2. This packing retainer 9
It is composed of a tubular portion 9a which is loosely penetrated by the shaft 3 and comes into contact with the gland packing 4, and a main body 9b which is integral with the tubular portion 9a.
As shown in FIG. 2, a pair of bolts 10, 10 which are symmetrically fixed to the packing box 2 with the shaft 3 interposed therebetween are penetrated and slidably provided in the axial direction of the shaft 3.
By changing the tightening amount of the nuts 11 and 11 screwed into 0, the tightening amount of the tubular portion 9a to the gland packing 4 can be adjusted. Further, in the main body 9b of the packing retainer 9, a gap 12 with the shaft 3 (in this embodiment, 2
mm), and an annular second jacket chamber 13 is provided so as to surround the second jacket chamber 13 and the cooling water at room temperature is supplied (about 1 to 10 liters / minute) from the lower water injection port 14. The packing presser 9 can be cooled by discharging it through the jacket chamber 13 and the upper drainage port 15.
Further, the main body 9b is provided with a hollow accumulating chamber 16 communicating with the gap 12, and a discharge port 17 (diameter of 30 mm) having a circular horizontal section communicating with the accumulating chamber 16 and opening downward. There is.

The shaft sealing device 1 configured as described above adjusts the amount of tightening of the packing retainer 9 by the bolt 10 and the nut 11 so that the molten plastic 8 can be operated during normal operation of the pump.
Is leaked from between the gland packing 4 and the shaft 3 by the pump pressure, and the tubular portion 9a of the packing presser 9 and the shaft 3 are
It is discharged to the gap 12 between During the operation of the pump, the steam flowing from the inlet 6 through the first jacket chamber 5 to the outlet 7 absorbs the heat of the packing box 2 to indirectly cool the gland packing 4, and the decomposition process of about 300 to 450 ° C. The molten plastic is cooled to about 150-250 ° C. Moreover, since the temperature of the steam here is set to a temperature higher than the melting point of the molten plastic 8 transferred by the pump, the plant and the apparatus are stopped, the pump is stopped, and the heat supply to the pump is cut off. After the molten plastic inside the pump is cooled and solidified, it is also used to melt the solidified plastic in the gland packing 4 and the casing body before operating the pump again. In this way, the plastic in the decomposition process is discharged to the gap 12 as a high temperature liquid, but the packing presser 9 absorbs the heat by the cooling water passing through the second jacket chamber 13 and the temperature drops to near room temperature. Therefore, the molten plastic comes in contact with the packing retainer 9 and is lower than the melting point (about 120 ° C).
Is cooled to room temperature), is extruded into the accumulating chamber 16 while being solidified in the gap 12, and is discharged from the discharge port 17 as it is. Therefore, the pyrolyzed plastic leaked from the shaft sealing device 1 is finally collected as a solid matter,
Not only is there no danger of ignition or ignition, it is safe and it is easy to recharge the raw material tank. Further, since the molten plastic does not solidify in the gland packing 4, wear of the gland packing 4 and the shaft 3 is reduced, the life is extended, and the maintenance is simplified. Further, since the packing retainer 9 separated from the packing box 2 is cooled, the amount of heat absorbed from the pump main body is small, and the amount of cooling water can be reduced accordingly, and conversely, the cooling from the packing retainer 9 to the packing box 2 and the pump main body Since the action is not transmitted, the thermal efficiency of the fluid itself transferred by the pump does not decrease, and the thermal gradient in the pump main body becomes gentle, so that the thermal stress is reduced and the influence on the constituent parts of the pump is reduced.

In the above embodiment, the second jacket chamber 13
Although the stacking chamber 16 and the discharge port 17 are integrally provided with the packing retainer 9 as described above, the second jacket chamber 13a, the water injection port 14a, the drain port 15a, and the collection chamber 16 are shown in FIG.
If a and the discharge port 17a are separated from the packing retainer 9 and can be attached to and detached from the packing retainer 9 by the bolt 19 or other mounting means as the cooling unit 18, it can be easily applied to the existing pump and the molten plastic It can be used as a transfer pump. In the embodiment, the second jacket chamber provided in the packing retainer is formed by one annular shape, but the shape and size are not limited to those in the above embodiment, and the number thereof is not limited to the axial direction of the shaft. Two or more may be arranged in parallel. This design change is due to the accumulation chamber 16 and the outlet 1.
The same applies to the shape of 7, and the discharge port 17 may be formed in a rectangular shape, or may be provided laterally instead of downward, or a plurality thereof may be provided. Further, if the accumulating chamber 16 and the discharge port 17 are provided, it is convenient to collect the solidified plastic. However, by eliminating them, only the second jacket chamber 13 is integrated with the packing retainer 9.
Alternatively, it may be provided as a separate body.

Although the shaft sealing device of the present invention is applied to a gear pump in the above embodiment, any pump having a shaft sealing device using a gland packing may be used, such as a volute pump, a viscous pump, a piston pump or the like. It can be applied to various pumps. The shaft sealing device of the present invention decomposes when used in a pump used in a pyrolysis oil reduction plant or device that reuses waste plastic in which high-molecular plastic, low-molecular gasoline and kerosene are mixed. Since the molten plastic in the process is particularly high in temperature as described above, the cooling effect on the leaked substance is effectively exhibited as in the example, which is an optimum embodiment. However, the present invention is a relatively low temperature manufacturing process. It is needless to say that the present invention can also be adopted in a pump in which molten plastic or the like is used as a transfer fluid, and a sufficient cooling effect can be achieved here as well.

[0010]

As described above, according to the present invention, the liquid molten plastic leaking in the molten plastic transfer pump can be independently recovered as a safe solid substance without the risk of ignition or burns, and is easy to handle. It can be easily re-charged as a raw material, wear between the spindle and gland packing is reduced, and maintenance work is reduced. In addition, since the packing retainer performs the cooling action, it has little effect on the pump body side, the thermal efficiency of the molten plastic transferred by the pump does not decrease, and the thermal gradient inside the pump body increases and the thermal stress also increases significantly. Therefore, there is no possibility that the life of the pump constituent material is shortened or the pump is thermally deformed. Further, the amount of heat absorption is smaller than that in the case of cooling the packing box, which leads to the saving of the amount of cooling water. When the jacket chamber is built in the packing retainer as in claim 2, the cooling effect is further enhanced, and when it is detachable as a separate body as in claim 3, it can be easily applied to an existing pump shaft sealing device. . Further, when the packing presser is provided with the discharge passage as in claim 4, the recovery of the solidified plastic is facilitated and the reuse in the raw material tank is convenient.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of a shaft sealing device for a molten plastic transfer pump of the present invention.

FIG. 2 is an end view taken along the line AA of FIG.

FIG. 3 is an explanatory diagram showing another embodiment of the present invention.

FIG. 4 is an explanatory view showing a conventional shaft sealing device for a pump.

[Explanation of symbols]

1 ... Shaft sealing device, 2 ... packing box, 3 ... shaft,
4 ... Gland packing, 5 ... First jacket chamber, 6
..Inlet, 7 ... Outlet, 8 ... Molten plastic, 9 ...
・ Packing retainer, 10 ・ ・ Bolts, 11 ・ ・ Nuts, 1
2 ・ ・ Gap, 13 ・ ・ Second jacket chamber, 14 ・ ・ Water injection port, 15 ・ ・ Drainage port, 16 ・ ・ Collection chamber, 17 ・ ・ Drainage port, 18 ・ ・ Cooling unit.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display area F04C 29/04 D

Claims (4)

[Claims] 1. A gland packing is interposed between a packing box integrally formed with the main body casing and a main shaft penetrating the packing box and protruding to the outside, and a packing retainer is provided outside the main body casing. A shaft sealing device for a molten plastic transfer pump that discharges molten plastic transferred in the main body casing from the gland packing by adjusting the leakage amount by adjusting the tightening amount of the packing press and discharging it from between the main shaft and the packing press. There is provided a shaft sealing device for a molten plastic transfer pump, wherein a jacket chamber is provided in the packing retainer in a non-contact manner with a main shaft. 2. The shaft sealing device for a molten plastic transfer pump according to claim 1, wherein the jacket chamber is built in a packing retainer. 3. The shaft sealing device for a molten plastic transfer pump according to claim 1, wherein the jacket chamber is detachably attached to the packing retainer. 4. The molten plastic transfer pump according to claim 1, wherein the packing retainer is provided with a leakage material discharge passage communicating with a gap between the main shaft and the packing retainer. Shaft seal device.