JPH0649194A - Shaft seal device of vacuum reactor - Google Patents

Abstract

PURPOSE:To improve the sealing performance of a gland packing of a shaft seal device to thereby enable a troubleless stable operation. CONSTITUTION:A proper pressure is applied to the surface of a gland packing 10 by using a protective ring 13 which has a spring installed therein and is placed in a gland box and the pressure of a sealing liq. is kept lower than or about the same as that of the inside of a vacuum reactor by evacuating through a sealing-liq. injection nozzle 6 which is connected to an evacuation system. Thus, the leak of the sealing liq. into the reactor is prevented and a satisfactory working of the ring 13 is obtd. Simultaneously, lubrication of the packing 10 all the time by the liq. becomes possible and troubles, such as seizure of a stirrer shaft or intrusion of a foreign matter, e.g. a degraded polymer or a carbonization product into the reactor, are avoided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a shaft seal device for a horizontal vacuum reactor having a high-viscosity liquid inside, and in particular, uses a gland packing for a horizontal vacuum reactor of polyethylene terephthalate or a polyester mainly composed of polyethylene terephthalate. The present invention relates to a shaft seal device.

[0002]

2. Description of the Related Art In a horizontal polymerization vacuum reactor handling a molten polymer of polyester, the seal portion of the stirring shaft using a gland packing is easily wedged by the wedge effect due to the deflection of the stirring shaft, and the in-machine polymer is solidified and carbonized. It may even damage the stirrer shaft and render the reactor inoperable.

In order to prevent this, a method of injecting a seal liquid into the gland seal portion can be considered. However, the sealing performance of the seal portion is low, and the pressure inside the reactor is lower than the pressure of the seal portion. Therefore, the seal liquid immediately leaks into the reactor, its function cannot be fully achieved, and the operating state becomes unstable.

Further, when the seal liquid is added, the surface pressure on the seal portion of the gland packing may change, which may further deteriorate the sealing performance.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above problem and maintains a proper surface pressure of the gland packing to improve its sealing performance, and at the same time, the gland seal part is constantly lubricated with a seal liquid to obtain a carbonized polymer. The present invention provides a bearing device for a horizontal vacuum polymerization reactor, in which damage to the stirring shaft is prevented, and a stable vacuum reaction is performed.

[0006]

That is, the present invention relates to a shaft sealing device using a gland packing of a polymerization vacuum reactor, and a spring for pressing the gland packing to a predetermined pressure on the rear part of the gland packing incorporated in a gland box. In addition to the internal protection ring, the gland box was provided with a seal liquid injection nozzle, and the gland box was connected to a vacuum generating means for keeping the box pressure lower than or equal to the reactor internal pressure. It is a shaft seal device for a vacuum reactor which is a feature.

[0007]

[Function] In a shaft sealing device using a gland packing of a reactor that carries out a polymerization reaction in a vacuum, a sealing liquid which gives a proper surface pressure to the gland packing by a protective ring having a spring and communicates with a vacuum generating means. The supply pot holds the seal liquid under vacuum at a pressure substantially equal to or lower than the pressure inside the reactor, thereby preventing the seal liquid from leaking into the reactor and promoting the sound operation of the protection ring. At the same time, the gland packing is constantly infiltrated with the sealing liquid, so that the sealing liquid can be constantly lubricated, and problems such as seizure of the agitator shaft and entry of foreign matter such as deteriorated polymer and carbide into the machine are almost completely eliminated.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. Figure 1
2 is a sectional view showing an embodiment of the present invention, FIG. 2 is an enlarged view of a main part of the shaft sealing portion of FIG. 1, and FIG. 3 is a system diagram of the entire apparatus.

In FIG. 3, 1 is a horizontal vacuum polymerization reactor,
Reference numeral 2 is a vacuum pump, and 3 is a seal liquid pot, and the vacuum pump 2 can make the pressure inside the seal liquid pot 3 lower than the pressure inside the reactor 1. 4 is a drain pot for the seal liquid.

Reference numeral 5 is a shaft sealing device for the stirring shaft 1a using a gland packing, the cross section of which is shown in FIG. 6
Is a seal liquid injection nozzle, 7 is a seal liquid pressure equalizing nozzle,
Reference numeral 8 is a seal liquid draining nozzle.

In FIG. 1, reference numeral 10 denotes a gland packing of the shaft sealing device 5, which is inserted into the gland box 11 and holds a seal. Grand box 11
Is provided with a seal liquid injection nozzle 6 and is incorporated in the nozzle 12 of the reactor.

A bearing 19 and a bearing box 20 are provided with a pressure equalizing nozzle 7 for the seal liquid and a liquid discharge nozzle 8 for the seal liquid. Reference numeral 21 is an oil seal, and 22 is a bearing cover.

Here, if the sum of the pressure in the gland box 11 and the head of the seal liquid is made equal to the pressure in the reactor, the seal liquid can be always held in the gland box 11 and the gland packing 10 is lubricated. Is possible. In this case, the pressure inside the reactor is usually controlled to be almost constant, and accordingly, the vacuum pump 2 is operated so that the pressure inside the sealing liquid pot or the gland box 11 reaches a predetermined value, or the gland box 11 is operated. The pressure in the box 11 may be controlled by a vacuum generating means such as a vacuum pump or a regulating valve so that the pressure in the box 11 is kept at a predetermined value in conjunction with the pressure inside the reactor.

Reference numeral 13 is a protective ring of the gland packing pressing spring shown in FIG. 2. The protective ring 13 is fixed to the gland box 11 by bolts. The gland packing pressing member 14, the protective plate 15, the support rod 16, and the O-ring 1 are provided.
7, a spring 18 and the like. The spring constant of the spring 18 is usually 1.0 to 1.5 kg / mm, although it depends on the type of the gland packing 10.

Here, even if the state of the gland packing 10 is changed by the sealing liquid, the gland packing retainer 14 slides following the change due to the spring force of the spring 18, so that an appropriate surface pressure should be constantly applied to the gland packing. You can Furthermore, since the seal liquid is always retained in the gland box 11, the O-ring 17 operates soundly due to the lubrication, and foreign matter is prevented from entering the spring 18, so that the packing has an appropriate surface pressure. Does not impair the function of giving.

[0016]

As described above, according to the present invention, it is possible to maintain an appropriate surface pressure on the gland packing and constantly lubricate the seal liquid, and the polymer that has entered the gland box is carbonized to cause the stirrer shaft to seize. It is possible to almost completely eliminate troubles such as foreign matter such as deteriorated polymer and carbide entering the machine, and it is possible to operate smoothly and stably obtain high quality products. It has a remarkable effect of becoming.

[Brief description of drawings]

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

FIG. 2 is an enlarged view of a main part of the shaft sealing portion of FIG.

FIG. 3 is a system diagram for explaining the present invention.

[Explanation of symbols]

 1 Horizontal vacuum polymerization reactor 1a Stirrer shaft 2 Vacuum pump 3 Sealing liquid pot 5 Shaft sealing device 6 Sealing liquid injection nozzle 7 Sealing liquid pressure equalizing nozzle 10 Grand packing 11 Grand box 12 Reactor nozzle 13 Protective ring 18 Spring 20 Bearing box

Claims (1)

[Claims] 1. A shaft sealing device using a gland packing of a polymerization vacuum reactor, wherein a protection ring having a spring for pressing the gland packing to a predetermined pressure is provided at the rear part of the gland packing incorporated in a gland box. A shaft seal of a vacuum reactor, characterized in that a seal liquid injection nozzle is provided in the gland box, and the gland box is connected to a vacuum generating means for maintaining the inside of the box at a pressure lower than or equal to the reactor internal pressure. apparatus.