CN113154123A

CN113154123A - Double-layer sealing structure

Info

Publication number: CN113154123A
Application number: CN202110400351.1A
Authority: CN
Inventors: 王晗; 张旭阳; 张鲲羽; 李一兴
Original assignee: 704th Research Institute of CSIC
Current assignee: 704th Research Institute of CSIC
Priority date: 2021-04-14
Filing date: 2021-04-14
Publication date: 2021-07-23

Abstract

The invention relates to a double-layer sealing structure which comprises a valve rod and a valve body matched and connected with the valve rod, wherein a lower gland is fixedly and hermetically connected in the upper end of the valve body, the upper end of the lower gland is connected with an upper gland through three fastening structures, a plurality of layers of graphite sealing filler are arranged between the valve rod and the lower gland for sealing, the lower end of the upper gland is connected with the graphite sealing filler through an upper bushing, and the graphite sealing filler in the lower gland is compressed by the upper gland through the three fastening structures and the upper bushing. The use of this structure can improve the gas leakage problem that meets among the current valve rod seal structure, reduces the working steam use amount of gland sealing air exhaust system. Has wider application prospect in high-pressure steam machinery.

Description

Double-layer sealing structure

Technical Field

The invention relates to a sealing structure in a marine turbo generator set, in particular to a sealing structure for a high-pressure working medium.

Background

The sealing technology for sealing the valve rod of the marine turbo generator with the sealing groove is commonly used. Through turning out the seal groove on the valve rod, reduce the leakage quantity of leakage quantity and the leakage volume of air of steam to make steam can not leak into in the atmosphere through the mode that sets up the air suction cavity on the valve rod.

A conventional seal groove seal structure is shown in fig. 1. Although the sealing groove structure can play a certain sealing role, the use of the sealing groove can not prevent high-pressure steam from flowing to the air extraction chamber through the gap between the shaft holes. And the structure also has a large air leakage amount. The air extraction system needs to consume certain working steam to achieve lower suction pressure, and the larger leakage amount can increase the consumption of the working steam, so that the air consumption of the whole unit is increased. Meanwhile, the structure cannot achieve the sealing effect under the condition that the air exhaust system fails. High-pressure steam leaks into the atmosphere through the gap between the shaft holes, condenses to water above the valve rod, and causes the whole valve body to generate the problems of corrosion and the like.

Therefore, in view of the above problems, a new double-layer sealing structure needs to be provided. The use of this structure can make the sealed effect of valve body better, and this seal structure can guarantee the validity of vapor seal system under the condition that air exhaust system became invalid.

Disclosure of Invention

The invention aims to solve the problem of providing a double-layer sealing structure which can be applied to the failure of an air extraction system and the loosening of bolts, the structure can ensure that the sealing effect of high-pressure steam is better, and the leakage of the steam caused by the failure of the sealing system and the untightening of the bolts can be avoided.

In order to achieve the purpose, the technical scheme of the invention is as follows: the utility model provides a double-deck seal structure, has a valve rod and the valve body of being connected with the valve rod cooperation, gland under the valve body upper end internal fixation sealing connection, gland upper end is connected the upper gland through three fastening structure down, it seals to set up multilayer graphite packing between valve rod and the lower gland, through last bush connection between upper gland lower extreme and the graphite packing, compress tightly the graphite packing in the gland down through three fastening structure by last bush by last gland.

Further, the upper end of the valve body is fixedly connected with a lower gland through a bolt.

Furthermore, the lower gland is connected with the valve body in a sealing mode through a sealing ring.

Further, the lower gland and the valve body are fixed together through three bolts with 120-degree intervals.

Furthermore, the valve body and the lower pressing cover are in clearance fit.

Furthermore, a lower bushing is arranged in the lower end of the valve body, and the valve rod is in sliding connection with the lower bushing in the valve body in a matched mode.

Further, the three fastening structures are arranged at 120 ° intervals.

Furthermore, the fastening structure is composed of a stud, a nut and three disc springs, wherein the three disc springs are sleeved on the stud and are positioned between the nut on the stud and the upper gland.

Further, the graphite sealing filler is divided into an upper section and a lower section, and the upper section and the lower section are connected with each other through a supporting block; the position corresponding to the middle supporting block is an air pumping hole; the section of the middle supporting block is of an I-shaped structure, and a small hole is formed in the middle of the I-shaped structure; the air pumping chambers on two sides of the I-shaped structure can prevent steam from flowing out through other gaps.

Further, the graphite sealing filler is a flexible sealing filler.

The invention has the beneficial effects that:

the novel double-layer sealing structure adopted by the invention has the following characteristics:

the graphite sealing filler adopted by the valve rod 1 has a good sealing effect, and the sealing effect of the valve rod can be ensured under the condition that an air exhaust system is not used. And the use of working steam can be reduced without using a steam seal system, so that the efficiency of the whole unit is improved.

2 different fastening means are adopted between the lower gland and the upper gland. The disc spring sealing structure adopted by the upper gland can ensure that the sealing packing cannot be loosened in the repeated pulling of the valve rod in long-term use, so that the phenomena of steam leakage, air leakage and the like are caused.

The use of this structure can improve the gas leakage problem that meets among the current valve rod seal structure, reduces the working steam use amount of gland sealing air exhaust system. Has wider application prospect in high-pressure steam machinery.

Drawings

FIG. 1 is a schematic view of a conventional seal groove seal structure;

FIG. 2 is a cross-sectional view of a double-layer seal structure of the present invention;

FIG. 3 is a schematic view showing the direction of the flow of the leakage steam in the double-layer sealing structure of the present invention;

in the figure: the valve comprises a valve rod 1, a stud 2, a nut 3, a disc spring 4, an upper gland 5, a bolt 6, a lower gland 7, a lower bushing 8, a valve body 9, a sealing ring 10, graphite sealing filler 11 and an upper bushing 12.

Detailed Description

The invention is further described with reference to the following figures and examples.

As shown in fig. 2, the sealing function of the double-layer sealing structure of the present invention is mainly achieved by means of a sealing ring and graphite sealing packing.

The structure comprises a valve rod 1, a stud 2, a nut 3, a disc spring 4, an upper gland 5, a bolt 6, a lower gland 7, a lower bushing 8, a valve body 9, a sealing ring 10, graphite sealing packing 11 and an upper bushing 12. The lower end of the valve body 9 is internally provided with a lower bushing 8, the upper end of the lower bushing is fixedly connected with a lower gland 7 through a bolt 6, the upper end of the lower gland 7 is connected with an upper gland 5 through a stud 2, a nut 3 and a disc spring 4, the valve rod 1 is in sliding connection with the lower bushing 8 in the valve body 9 in a matching manner, a plurality of layers of graphite sealing packing 11 are arranged between the valve rod 1 and the lower gland 7 for sealing, an upper bushing 12 is arranged between the graphite sealing packing 11 at the upper end and the upper gland 5, and the lower gland 7 is in sealing connection with the valve body 9 through a sealing ring 10.

Wherein a sealing ring 10 is used for the gap between the valve body 9 and the lower gland 7. The lower gland 7 and the valve body 9 are fixed together through three bolts 6 with 120 degrees of intervals. Wherein for clearance fit between valve body 9 and the lower pressure cap 7, the reciprocating of valve rod 1 can not produce the effect of direct power to valve body 9, and bolt 6 is difficult for taking place phenomenons such as pine takes off after the installation is screwed up.

The graphite packing 11 is mainly used for sealing the gap between the upper liner 12 and the lower gland 7. The upper bushing 12 is pressed against the lower gland 7 by the upper gland 5 through three fastening arrangements. The three fastening structures are spaced 120 apart. Each fastening structure is composed of a stud 2, a nut 3 and three disc springs 4. Graphite sealing filler 11 has certain flexibility, can make dish spring 4 produce certain deformation through screwing up nut 3 when the installation, and the elasticity that dish spring 4 produced can compress tightly graphite sealing filler 11 and take place certain deformation through last gland 5 and last bush 12, and then makes the gap between graphite sealing filler 11 and the valve rod 1 can be eliminated. The force transmitted to the graphite sealing packing 11 by the valve rod is eliminated by the deformation of the disc spring 4 when the valve rod 1 moves upwards, and the disc spring 4 applies pressure to the graphite sealing packing 11 again after the valve rod 1 stops moving so as to ensure a certain sealing force.

The graphite sealing packing 11 is divided into two sections up and down, and a section of middle supporting block is arranged in the middle and connected with each other. The position corresponding to the middle supporting block is an air pumping hole. The section of the middle supporting block is in an I-shaped structure, and a small hole is formed in the middle of the structure. The air pumping chambers on two sides of the I-shaped structure can prevent steam from flowing out through other gaps.

When in normal use, the air pumping chamber is in a closed state, and the sealing effect of the steam seal structure can be ensured only through the graphite sealing filler. The air-pumping chamber is used as a spare sealing means when the graphite sealing filler is used for a long time.

Fig. 3 shows the steam flow direction after the graphite sealing filler is worn in long-term use and the air exhaust system is opened.

When the double-layer sealing structure is installed, the lower bushing is installed on the valve body, and then the valve rod penetrates through the lower bushing from bottom to top. And then, placing the sealing surface on a step of the valve body, installing the lower pressing block on the valve body, installing the bolt and screwing down. The method comprises the steps of putting graphite sealing filler into a gap between a lower pressing block and a valve rod and putting the graphite sealing filler into a middle supporting block, continuously putting the graphite sealing filler into the middle supporting block, then putting an upper bushing and an upper pressing cover above the graphite sealing filler, screwing a stud into the lower pressing cover through a hole reserved in the upper pressing cover, putting a disc spring above the stud, and finally screwing a nut and pressing the disc spring downwards until the disc spring is deformed to a certain extent.

Claims

1. The utility model provides a double-deck seal structure, has a valve rod and the valve body of being connected with the valve rod cooperation, its characterized in that: the valve body is characterized in that a lower gland is fixedly and hermetically connected in the upper end of the valve body, the upper end of the lower gland is connected with an upper gland through three fastening structures, a plurality of layers of graphite sealing packing are arranged between the valve rod and the lower gland for sealing, the lower end of the upper gland is connected with the graphite sealing packing through an upper bushing, and the graphite sealing packing in the lower gland is compressed through the upper bushing by the upper gland through the three fastening structures.

2. The double-layer sealing structure of claim 1, wherein: the upper end of the valve body is fixedly connected with the lower gland through a bolt.

3. The double-layer sealing structure of claim 1, wherein: the lower gland is connected with the valve body in a sealing mode through a sealing ring.

4. The double-layer sealing structure of claim 1, wherein: the lower gland and the valve body are fixed together through three bolts with 120-degree intervals.

5. The double-layer sealing structure of claim 1, wherein: the valve body is in clearance fit with the lower pressing cover.

6. The double-layer sealing structure of claim 1, wherein: the lower end of the valve body is internally provided with a lower bushing, and the valve rod is in sliding connection with the lower bushing in the valve body in a matching manner.

7. The double-layer sealing structure of claim 1, wherein: the three fastening structures are arranged at 120 ° intervals.

8. The double-layer sealing structure of claim 1, wherein: the fastening structure consists of a stud, a nut and three disc springs, wherein the three disc springs are sleeved on the stud and are positioned between the nut on the stud and the upper gland.

9. The double-layer sealing structure of claim 1, wherein: the graphite sealing filler is divided into an upper section and a lower section, and the upper section and the lower section are mutually connected through a supporting block; the position corresponding to the middle supporting block is an air pumping hole; the section of the middle supporting block is of an I-shaped structure, and a small hole is formed in the middle of the I-shaped structure; the air pumping chambers on two sides of the I-shaped structure can prevent steam from flowing out through other gaps.

10. The double-layer sealing structure of claim 1, wherein: the graphite sealing filler is flexible sealing filler.