JPH0511357Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a gear pump for transporting a thermoplastic resin solution such as polyester, nylon, polyethylene, etc.

[Conventional technology]

This type of thermoplastic resin solution is heated to about 300℃ to reduce the viscosity to several thousand poise and turn it into starch syrup, which weighs 50kg.
It is pumped by low speed rotation at a pressure exceeding f/cm ² . For example, as shown in FIG. 3, there has been proposed a shaft sealing part of a gear pump used for this transfer, in which a double mechanical seal 54 is attached to a housing 53 through which a gear drive shaft 51 passes (for example, (See Publication No. 60-56189). The back-to-back type double mechanical seal 54 shown in FIG.
The space is partitioned into three by a pair of sealed end surfaces 55 and 56, and a chamber 59 is filled with flushing liquid at about 300° C. (same temperature as the plastic resin solution), which is press-fitted from a passage 57 and discharged from a passage 58. This prevents the thermoplastic resin solution in the chamber 60 from leaking into the chamber 59 from the sealed end surface 55. In addition, in the sealing method shown in FIG. 5, a ring-shaped gland packing 62 made of woven high-temperature carbon fiber or asbestos is inserted between the hole of the housing 64 and the shaft 65, and is pressed with a packing holder 66 to close the housing. 64 has a shaft sealing function. In this sealing method, the thermoplastic resin solution is leaked through the gap between the packing 62 and the shaft portion 65.

[Problem that the invention attempts to solve]

However, in the double mechanical seal 54 shown in FIG. 4, the flushing liquid that is press-fitted into the chamber 59 and seals the high viscosity thermoplastic resin solution in the chamber 60 with the sealed end surface 55 infiltrates into the chamber 60 and seals the thermoplastic resin. Sometimes it got mixed into the solution. Further, since the thermoplastic resin solution comes to a dead end before the sealing end face 55, there is a problem in that the thermoplastic resin solution stagnates in the inner part of the mechanical seal and deteriorates in quality. In the method using a gland packing, the thermoplastic resin solution leaks through the gap between the gland packing 62 and the shaft portion 65.
Although deterioration of the solution due to solution stagnation can be avoided, it is difficult to adjust the amount of solution leakage. That is, if the packing is slightly loosely tightened, the amount of leakage will suddenly increase, resulting in wasted material, and if the packing is slightly overtightened, the amount of leakage will almost disappear, resulting in the problem of quality deterioration. In addition, the packing that is subjected to high temperature and high pressure lacks durability, causing problems such as the fibers being broken into pieces and the pieces mixed into the solution.

The present invention was developed in view of the above points, and is a gear pump that can adjust the amount of leakage of thermoplastic resin solution to the outside at the shaft sealing part to an appropriate amount, and prevents foreign matter from getting mixed into the thermoplastic resin solution from the shaft sealing part. The purpose is to provide a shaft seal for.

[Means for solving problems]

The first configuration of the present invention to achieve this purpose is
This will be explained using FIG.

The housing 2 with the seal cylinders 5, 39 protrudingly provided and the shaft parts 1, 35 with the seal rings 14, 37 protrudingly installed in the shaft seal part through which the shaft parts 1, 35 of the gear pump pass are connected to the seal cylinder. The end surfaces 25, 45 of the housing 2 and the end surfaces 26, 43 of the seal ring are fitted so as to face each other, and the housing 2 and the seal ring 14, 37
and between the shaft portions 1, 35 and the seal cylinders 5, 39 to form passages that allow external leakage of the thermoplastic resin solution. The seal cylinders 5, 39 are attached so as to be movable, and the end surfaces 25, 45 of the seal cylinders 5, 39 and the seal ring 14,
The gap t between the end faces 26 and 43 of 37 is adjusted.

[Effect]

Passages are formed between the seal cylinders 5, 35 and the shaft parts 1, 35 and between the seal rings 14, 37 and the housing 2 to allow external leakage of the thermoplastic resin solution. End faces 25, 45 of bodies 5, 39 and end faces 2 of seal rings 14, 37
6 and 43, and this gap t can be finely adjusted by displacing the seal cylinders 5 and 39 in the axial direction, so the leakage amount of the thermoplastic resin solution can be easily controlled from the outside. Can be set. Therefore, there is no excess or deficiency in the amount of thermoplastic resin solution leaking, and solution loss can be kept to the necessary minimum, and there is no stagnation of the solution, so that deterioration of the solution due to stagnation does not occur. In addition, since the shaft seal is non-contact and is lubricated by the thermoplastic resin solution passing through it, there is no need to worry about wear or damage to the shaft seal, and wear particles and other foreign matter are removed from the thermoplastic resin solution in the gear chamber. There is no chance of contamination.

〔Example〕

Embodiments of the present invention will be described based on the drawings. In Fig. 1, 1 is a drive shaft of a gear pump, 2 is a housing fixed to a casing 3 of the gear pump, and a seal cylinder 5, which can be freely inserted into and taken out of a hole 4, is attached to the end with a bolt 6. A hole 9 (smaller in diameter than the hole 4) and a hole 9' (larger in diameter than the hole 9) are formed in the inner part of the portion 4. The casing 3 is equipped with a bearing that rotatably supports the drive shaft 1 with a bearing metal 8 that is installed in a hole 7 formed between a gear chamber (not shown) and a hole 9'. A spacer 10 is fitted into the hole 9' of the housing 2. On the other hand, a spacer 12 that faces the annular recess 11 formed on the inner peripheral side of the end surface of the seal cylinder 5 side of the spacer 10 is in contact with the stepped portion 13 of the drive shaft 1, and the spacer 12 is attached to the step portion 13 of the housing 2. A seal ring 14 located in the hole 9, a spacer 15 located in the hole 24 of the seal cylinder 5, and a flanged spacer 1 whose side in contact with the spacer 15 has the same diameter as the spacer 15.
6. Contact the stopper 17 in order, and then press the stopper 17
is secured to the annular groove 19 of the drive shaft 1 with the screw 18, and the spacer 12 and the seal ring 1 are secured by the axial screw 20 of the stopper 17 and the stepped portion 13 of the drive shaft 1.
4. The spacers 15 and 16 are restrained from moving in the axial direction, and the seal ring 14 is fixed by the pin 21.
The spacer 15 is rotated together with the drive shaft 1 by a screw 22. However, spacer 1
0 between the annular recess 11 and the spacer 12, between the spacer 10 and the seal ring 14, between the seal ring 14 and the housing 2, and between the spacer 15 and the seal cylinder 5. Provide a gap to allow leakage. In addition, when the end surface 25 of the seal cylinder 5 is in contact with the step 23 that is the boundary between the holes 4 and 9 of the housing 2, there is a minimum necessary gap between the end surface 25 and the end surface 26 of the seal ring 14. The reference gap T ₀ is set as follows. The size of the gap t between the end faces 25 and 26 can be set from the outside. For example, an adjustment screw 28 is provided on the flange 27 of the seal cylinder 5, and the end surface 25 of the seal cylinder 5 is adjusted to the step 23.
The adjustment screw 28 is brought into contact with the end surface 29 of the housing 2 in a state in which it is brought into contact with the housing 2, and an initial gap between the end surface 29 and the flange 27 is determined.

Next, loosen the bolt 6 and fix the seal cylindrical body 5 to the housing 2 with the bolt 6 through a gauge that has a thickness equal to the initial clearance plus the thickness obtained by subtracting the reference clearance T ₀ from the clearance to be set. , the required clearance can be obtained.

In the embodiment shown in FIG. 2, a bearing metal 8 for supporting a drive shaft 35 is provided in the casing 3, and a spacer 38 and a seal ring 37 are fitted into the end of the hole 7 and the hole 9' of the housing 2. It is the same as that shown in FIG. 1 that gaps are provided between the housing 2 and the seal ring 37 and between the housing 2 and the seal ring 37 to allow external leakage of the thermoplastic resin solution.
The seal cylinder 39 has a gap between it and the drive shaft 35 to allow leakage of solution to the outside, and the seal ring 37 has radial grooves 44 on the seal cylinder facing surface 43.
A large number of pins 36 are formed in the elongated hole 48, and the pin 36 is inserted into the drive shaft 35 so as to be movable. The seal cylinder 39 has a step 41 formed at its base near the flange 40, and when the step 41 is in contact with the end surface 42 of the housing 2, the gap between the seal ring 37 and the spacer 38 and the seal ring 37 and the seal cylindrical body 39 is the required minimum clearance. This can be obtained by setting the seal cylinder 39 in the housing 2 after checking the gap between the stepped portion 41 and the end face 42 using a block gauge or the like. Therefore,
A desired gap can be set accurately from the outside. In this embodiment, the seal ring 37 receives pressure from the thermoplastic resin solution before and after the seal ring 37 and comes to rest at a position where the pressing forces on both end surfaces are balanced. The passage gap is automatically adjusted according to pressure changes to control the amount of solution leaking to the outside.

Note that the viscosity of the thermoplastic resin solution passing through the shaft seal increases as the temperature decreases. Figure 2)
Spiral grooves 32 and 47 are formed in the grooves 32 and 47 for sending out the thermoplastic resin solution. Further, the shaft portion referred to in the present invention is the drive shaft 1, 35 in this embodiment.

[Effect of idea]

As is clear from the above explanation, according to the present invention, the housing having a seal cylinder protruding thereon and the shaft part having a seal ring protruding therethrough are made of thermoplastic resin at the shaft seal portion through which the shaft portion of the gear pump passes. In addition to forming a passageway that allows the resin solution to leak to the outside, the gap between the end face of the seal cylinder and the end face of the seal ring can be finely adjusted from the outside by the seal cylinder, so that heat can be prevented. The leakage amount of the plastic resin solution can be easily set from the outside. For this reason,
There is no excess or deficiency in the amount of thermoplastic resin solution leaked,
Loss of the solution can be kept to the necessary minimum, and since there is no stagnation of the solution, deterioration of the quality of the solution due to stagnation can be prevented. In addition, the shaft seal is a non-contact type, and as a result of the thermoplastic resin solution that passes between the shaft seals being lubricated, there is no need to worry about wear or damage to the shaft seal, ensuring the shaft sealing function, and preventing abrasion particles and other Foreign matter will not mix into the thermoplastic resin solution in the gear chamber.

[Brief explanation of the drawing]

Figures 1 and 2 are longitudinal sectional views of embodiments of the present invention, Figure 3 is a partially cutaway sectional view of a conventional gear pump for transferring thermoplastic resin solution, and Figure 4 is a cross-sectional view of a gear pump used in the same gear pump. FIG. 5 is a sectional view of a seal mechanism including a gland packing used in the same gear pump. 1...Shaft part, 2...Housing, 5, 39...
Seal cylinder body, 14, 37... Seal ring, 3
2,47...Spiral groove.

Claims (1)

[Scope of utility model registration request] At the shaft seal part where the gear pump shaft passes through,
A housing having a protruding seal cylinder body and a shaft part having a protruding seal ring are fitted together with the end face of the seal cylinder body and the end face of the seal ring facing each other, and a seal is formed between the housing and the seal ring and between the shaft part and the seal ring. A passage is formed between the seal cylinder and the cylinder to allow external leakage of the thermoplastic resin solution, and the seal cylinder is attached to the housing so as to be movable in the axial direction. A shaft sealing part for a gear pump, characterized in that a gap between an end face and an end face of a seal ring is adjusted.