JPH0669528U - Shaft seal structure inside the stuffing box - Google Patents

Abstract

(57) [Summary] [Purpose] Even if the internal pressure decreases due to fluctuations in the internal pressure of the equipment to be sealed, abnormal wear of the shaft 2 due to tightening of the first packing group 4 is prevented. [Structure] A first packing group 4, a sealing ring 5, and a second packing group 6 are provided between the stuffing box 1 and the shaft 2.
In the seal structure in which the shaft sealing member 7 configured by is loaded and the shaft sealing member 7 is axially pressed by the packing presser 8 to seal the shaft, the first packing group 4 on the inner side of the water sealing ring 5 It is constituted by hard rings 4A and 4B having an inner diameter slightly larger than the outer diameter of the shaft 2.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a shaft seal structure in a stuffing box that seals a shaft that reciprocates in the axial direction and a shaft support such as a rotary shaft.

[0002]

[Prior art]

 Conventionally, as a shaft seal structure in a stuffing box, a structure shown in FIG. 5 is known. This shaft seal structure has a plurality of gland packings from the back side between the stuffing box 1 and the shaft 2, more specifically, between the stuffing box 1 and the sleeve 3 attached to the outer periphery of the shaft 2. 1 A packing group 4 and a shaft sealing member 7 composed of a water sealing ring 5 and a second packing group 6 composed of a plurality of gland packings are loaded, and a packing holder 8 fitted from the inlet side of the stuffing box 1 is used. The shaft sealing member 7 is pressed, and water is supplied from the water sealing system 10 to the water sealing ring 5 through the water sealing passage 9 formed in the stuffing box 1 so as to enhance the lubrication and sealing action and seal the shaft. Is configured.

However, in the conventional shaft seal structure in which the first packing group 4 is composed of a plurality of gland packings, when the internal pressure P1 of the device to be sealed changes, and especially when the internal pressure P1 decreases, the first packing group 4 A phenomenon occurs in which the diameter is reduced and it is hugged by the shaft 2 and the shaft 2 is tightened. Therefore, the passage resistance of the water between the shaft 2 and the first packing group 4 becomes large, and the passage of the water supplied to the sealing ring 5 is hindered. As a result, the sealing water pressure P2 is increased, and at the same time, a high pressure is generated in the gap between the outer circumference of the first packing group 4 and the inner circumference of the stuffing box 1 which are formed by the diameter reduction of the first packing group 4. The sealing water flows in, a high sealing water pressure P2 is applied to the outer periphery of the first packing group 4, and the tightening force of the shaft 2 by the first packing group 4 is greatly increased. If the shaft-sealing equipment is continuously operated and the shaft 2 is rotated or reciprocated in such a state that the lubrication performance is reduced and the sliding resistance is large, abnormal wear occurs on the shaft 2. There is.

[0004]

[Problems to be solved by the device]

 The problem to be solved is that when the internal pressure decreases due to fluctuations in the internal pressure of the equipment to be sealed, the tightening force of the shaft by the first packing group increases significantly and abnormal wear occurs on the shaft.

[0005]

[Means for Solving the Problems]

 According to the present invention, a shaft sealing member composed of a first packing group, a liquid sealing ring, and a second packing group is loaded between a stuffing box and a shaft and fitted from the inlet side of the stuffing box. In the shaft sealing structure in the stuffing box that presses the shaft sealing member in the axial direction with the packing retainer to seal the shaft, the first packing group on the inner side of the liquid sealing ring has an inner diameter slightly larger than the outer diameter of the shaft. It is characterized by a hard ring that has a small diameter due to fluctuations in internal pressure. Even if the internal pressure decreases due to fluctuations in the internal pressure of the shaft-sealed machine, the shaft due to tightening of the first packing group Achieved the purpose of reliably preventing abnormal wear of.

[0006]

[Action]

 According to the present invention, even if the internal pressure of the shaft-sealed device fluctuates and drops, the first packing group does not shrink in diameter and cling to the shaft and tighten the shaft. Therefore, between the shaft and the first packing group. In addition, a small gap can always be secured. In addition, since proper passage of water between the shaft and the first packing group can be ensured and a rise in the sealing water pressure can be avoided, a high sealing water pressure is applied to the outer periphery of the first packing group 4 and the first packing group is The shaft is not tightened by the group.

[0007]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a vertical sectional view showing an example of a shaft seal structure in a stuffing box according to the present invention. Note that the same or corresponding portions as those of the conventional example described in FIG. In FIG. 1, the shaft seal structure has a first packing group from the back side between the stuffing box 1 and the shaft 2, more specifically, between the stuffing box 1 and the sleeve 3 attached to the outer circumference of the shaft 2. 4, a water seal ring 5 and a shaft seal member 7 composed of a second packing group 6 are loaded, and the shaft seal member 7 is pressed by a packing retainer 8 fitted from the inlet side of the stuffing box 1 to seal the water seal ring 5 Is configured to supply water from a water sealing system 10 through a water sealing passage 9 formed in the stuffing box 1 to enhance lubrication and sealing action for shaft sealing.

The second packing group 6C is composed of a plurality of gland packings, and the first packing group 4 is slightly larger than the outer diameter D1 of the sleeve 3 as shown in FIG. 2 and FIG. It has an inner diameter D2 smaller than the inner diameter D4 of the ring 5 and an outer diameter D3 that uniformly abuts the inner peripheral surface of the stuffing box 1. It is composed of two hard rings 4A and 4B, such as bronze or hard resin, which have rigidity such that the internal pressure P1 of the device to be sealed changes little even if the internal pressure P1 fluctuates and drops.

With such a configuration, even if the internal pressure P1 of the shaft-sealed device fluctuates and drops, the diameter of the first packing group 4 is not reduced and the shaft 2 is not clamped to the hug shaft 2. Therefore, a small gap 11 is always secured between the shaft 2 and the first packing group 4, and the sealing water can be properly passed therethrough, so that the shaft is sealed by exhibiting a high lubricating action and a sealing action. You can Further, since the sealing water properly passes between the shaft 2 and the first packing group 4, an increase in the sealing water pressure P2 can be avoided, so that the outer circumference of the first packing group 4 has a high sealing capacity as in the conventional case. The water pressure P2 is not applied, so that the diameter of the first packing group 4 is not reduced and the shaft 2 is not tightened. Therefore, it is possible to reliably prevent abnormal wear of the shaft 2 due to the tightening of the first packing group 4.

In the above embodiment, the first packing group 4 is described by being constituted by the hard rings 4A and 4B that are continuous in the circumferential direction, but the present invention is limited to the embodiment. Instead, as shown in FIG. 4, the first packing group 4 is formed by the hard rings 4A and 4B having a structure in which a semicircular member divided into two is integrally connected by a fastening material (not shown) such as a bolt. You may comprise.

[0011]

[Effect of device]

 As described above, according to the present invention, even if the internal pressure of the shaft-sealed device fluctuates and decreases, the first packing group does not contract the diameter of the first packing group and clasp the shaft. A small gap can always be secured between the packing groups. In addition, since proper passage of water between the shaft and the first packing group can be ensured and a rise in the sealing water pressure can be avoided, a high sealing water pressure is applied to the outer periphery of the first packing group 4, and There is no need to tighten the shaft with one packing group. Therefore, it is possible to reliably prevent abnormal wear of the shaft due to tightening of the first packing group.

[Brief description of drawings]

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

FIG. 2 is an enlarged front view of a hard ring that constitutes a first packing group.

FIG. 3 is an enlarged cross-sectional view showing a loaded state of a first packing group.

FIG. 4 is an enlarged front view showing a modified example of the hard ring that constitutes the first packing group.

FIG. 5 is a vertical sectional view showing a conventional example.

[Explanation of symbols]

 1 Stuffing box 2 Shaft 4 1st packing group 4A Hard ring 4B Hard ring 5 Water sealing ring (sealing ring) 6 2nd packing group 7 Shaft sealing member 8 Packing holder D1 Shaft outer diameter D2 Hard ring inner diameter

Claims (1)

[Scope of utility model registration request] 1. A first packing group, a liquid sealing ring, and a second packing.
A shaft sealing member configured by a packing group is loaded between a stuffing box and a shaft, and a packing holder fitted from the inlet side of the stuffing box axially presses the shaft sealing member to seal the shaft. In the shaft seal structure in the fing box, the first packing group on the inner side of the liquid sealing ring has an inner diameter slightly larger than the outer diameter of the shaft, and is composed of a hard ring that is hardly reduced in diameter due to internal pressure fluctuation. A shaft seal structure inside a stuffing box.