CN217030017U - An ultra-low temperature top-mounted ball valve - Google Patents

Abstract

An ultra-low temperature top-mounted ball valve mainly includes a valve body, a valve cover, a valve stem, and a ball. One end of the valve stem is connected to the ball. The valve cover is connected to the actuator. The valve cover adopts an elongated type. The valve stem is installed in the valve cover through the valve stem bearing at the upper and lower ends of the valve cover. The valve cover cavity between the upper and lower valve stem bearings is connected to the valve. There is a gap between the rods, and the gap communicates with the central cavity of the valve through the relief hole at the lower end of the valve cover. The utility model makes the valve safer and more reliable to use in the liquefied natural gas device, can be sealed reliably under the alternating temperature state of ultra-low temperature and normal temperature, and saves time and labor in assembling and manufacturing.

Description

An ultra-low temperature top-mounted ball valve

technical field

The utility model relates to the technical field of valve manufacturing, in particular to an ultra-low temperature top-mounted ball valve.

Background technique

The main component of LNG is methane, its liquefaction temperature is -163°C, and its volume expands about 600 times during gasification. As a new energy source, liquefied natural gas has been used in my country significantly in recent years. As one of the main valves of LNG plant, ultra-low temperature top-loading ball valve has obvious deficiencies in its technical level in my country. The main manifestations are: under the alternating working temperature load of low temperature and normal temperature, the sealing performance of the valve is unreliable; the valve seat structure needs to be further optimized, the valve needs to be simple and easy to install or maintain, and at the same time, it must meet the valve cavity in 1.06~ It can automatically release pressure at 1.25 times the design pressure.

Utility model content

The utility model provides an ultra-low temperature top-mounted ball valve, which effectively improves the use reliability of the ultra-low temperature top-mounted ball valve.

To achieve the above object, the utility model provides the following technical solutions:

An ultra-low temperature top-mounted ball valve mainly includes a valve body, a valve cover, a valve stem and a ball body. One end of the valve stem is connected to the ball body. The valve cover is connected to the actuator. The valve cover adopts an elongated type. The valve stem is installed in the valve cover through the valve stem bearing at the upper and lower ends of the valve cover. The valve cover cavity between the upper and lower valve stem bearings is connected to the valve. There is a gap between the rods, and the gap communicates with the central cavity of the valve through the relief hole at the lower end of the valve cover.

The gap between the inner cavity of the valve cover and the valve stem is 5mm.

The valve seat comprises a metal valve seat body and a soft sealing ring, the soft sealing ring is embedded in the groove of the valve seat body and forms a sealing pair with the ball.

The inner diameter of the soft sealing ring is a clearance fit with the inner diameter of the groove of the valve seat body, the outer diameter of the soft sealing ring is an interference fit with the outer diameter of the groove of the valve seat body, and the tail of the soft sealing ring is in the groove of the valve seat body. The bottom forms a sealing pair.

The tail of the soft sealing ring is provided with a chamfered structure.

It includes a spring seat, a spring is installed between the spring seat and the valve body, and the end of the spring seat and the positioning nut are in contact with each other through a bearing, and the positioning nut and the valve seat body are threadedly connected.

Compared with the prior art, the utility model has the beneficial effects that the valve is safer and more reliable to use in the LNG plant, can be reliably sealed under the alternating temperature state of ultra-low temperature and normal temperature, and saves time and labor in assembly and manufacture.

Description of drawings

Fig. 1 is the structural representation of the utility model;

Figure 2 is an enlarged schematic view of the lower part of the valve cover and the valve stem of the utility model;

3 is an enlarged schematic view of the upper seal of the valve stem of the present invention;

Figure 4 is a schematic diagram of the valve seat structure of the present invention;

In the figure: 1- valve seat, 2- ball, 3- valve body, 4- valve cover, 5- valve stem, 6- drip tray, 7- relief hole, 8- bracket, 9- actuator, 10- packing , 11- valve stem bearing, 12- valve seat body, 13- soft sealing ring, 14- spring seat, 15- bearing, 16- positioning nut.

Detailed ways

The technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the implementations. example. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

Referring to Figure 1, an ultra-low temperature top-mounted ball valve is composed of a valve seat 1, a sphere 2, a valve body 3, a valve cover 4, a valve stem 5, a drip tray 6, a bracket 8, an actuator 9, and the like. One end of the valve stem 5 is connected to the sphere 2, and the sphere 2 is sealedly connected to the valve seat 1 installed at the inlet and outlet of the valve body flow passage.

Referring to Fig. 2, the upper part of the valve stem 5 and the valve cover 4 are sealed by the packing 10. In order to ensure that the packing 10 does not freeze under the ultra-low temperature environment, the valve cover 4 is of an elongated type. This type of valve standard stipulates The height of the bonnet is not less than 350mm, and we lengthen it to 450mm through analysis and calculation. The purpose of lengthening the bonnet is to prevent the temperature of the packing position from being too low to cause the packing to freeze, thereby causing the problems of seal failure and valve switch jamming.

When designing the valve cover 4, the valve cover is lengthened as a whole, and at the same time, the matching area between the valve stem 5 and the valve cover 4 is also increased. In order to solve this problem, a set of valve stem bearings 11 are designed on the upper and lower shaft ends of the valve cover 4 and the valve stem 5 respectively (due to the large switching torque of the ball valve, the purpose of installing the bearings is to reduce the friction torque at this position, effectively reducing the The operating torque of the valve), there is a gap of about 5mm in the middle part, and two relief holes 7 are designed at the lower end of the valve cover 4 to connect the middle cavity of the valve with the valve stem gap to prevent gasification in this area due to temperature rise. .

Please refer to Figure 3. In order to ensure that the valve does not leak under the alternating working conditions of low temperature and normal temperature, after repeated analysis and calculation, the valve seat 1 is designed as a metal valve seat body 12 and a soft sealing ring 13, so that the line of the soft sealing ring 13 is designed. The difference between the expansion coefficient and the metal valve seat body 12 becomes large. The soft sealing ring 13 is embedded in the groove of the valve seat body 12 and forms a sealing pair with the ball 2 .

The inner diameter of the soft sealing ring 13 and the inner diameter of the groove of the valve seat body 12 are clearance fit, the outer diameter of the soft sealing ring 13 and the outer diameter of the groove of the valve seat body 12 are interference fit, and the tail of the soft sealing ring 13 is in contact with the outer diameter of the groove of the valve seat body 12. The bottom of the groove of the valve seat body 12 forms a sealing pair. It is achieved that the bottom surface of the metal valve seat 12 inlaid with the sealing groove and the bottom surface of the soft sealing ring 12 have a sealing effect design, and there is no radial sealing requirement.

The tail of the soft sealing ring 13 is provided with a chamfered structure, so that the sealing specific pressure can be ensured under high pressure and low temperature environments.

Please refer to FIG. 3 , in the present invention, the valve seat 1 relies on a cylindrical spring to provide a pre-tightening force to it, the spring is installed in the spring seat 14, the spring seat 14 is installed on the outer periphery of the metal valve seat 12, and one end of the spring seat 14 and the valve body pass through Spring connection, the other end is connected with the bearing 15 and the positioning nut 16, and the positioning nut 16 and the metal valve seat 12 are threadedly connected.

When the positioning nut 16 is tightened, since the friction force between the positioning nut 16 and the spring seat 14 is particularly large, a bearing 15 with a low friction coefficient is designed between the two, and the positioning nut 16 and the low friction coefficient bearing 15 are designed between the two. The contact surface is designed in the form of a convex surface, which reduces the friction surface and improves the installation efficiency of the positioning nut 16 .

The valve stem bearing 11 and the bearing 15 are made of stainless steel and PTFE, and the friction coefficient is 0.04.

Claims (6)

1. The utility model provides an ultra-low temperature top-mounted formula ball valve, mainly includes valve body, valve gap, valve rod, spheroid, and the spheroid is connected to valve rod one end, the spheroid with install the disk seat sealing connection in valve body runner inlet outlet department, the valve rod other end seals to pass through behind the valve gap and actuating mechanism is connected its characterized in that: the valve cover (4) is lengthened, the valve rod (5) is arranged in the valve cover at the upper end and the lower end of the valve cover through the valve rod bearing (11), a gap is reserved between the inner cavity of the valve cover (4) and the valve rod (5) between the upper valve rod bearing and the lower valve rod bearing, and the gap is communicated with the middle cavity of the valve through a discharge hole (7) at the lower end of the valve cover (4).

2. The ultra-low temperature top-loading ball valve according to claim 1, wherein: and the clearance between the inner cavity of the valve cover (4) and the valve rod (5) is 5 mm.

3. The ultra-low temperature top-mounted ball valve of claim 1, wherein: the valve seat (1) comprises a metal valve seat body (12) and a soft sealing ring (13), and the soft sealing ring (13) is embedded in a groove of the valve seat body (12) and forms a sealing pair with the ball body (2).

4. The ultra-low temperature top-loading ball valve according to claim 3, wherein: the inner diameter of the soft sealing ring (13) is in clearance fit with the inner diameter of the groove of the valve seat body (12), the outer diameter of the soft sealing ring (13) is in interference fit with the outer diameter of the groove of the valve seat body (12), and the tail part of the soft sealing ring (13) and the bottom of the groove of the valve seat body (12) form a sealing pair.

5. The ultra-low temperature top-loading ball valve according to claim 4, wherein: the tail part of the soft sealing ring (13) is provided with a chamfer structure.

6. The ultra-low temperature top-mounted ball valve of claim 1, wherein: the valve seat comprises a spring seat (14), a spring is arranged between the spring seat (14) and a valve body, the end part of the spring seat (14) is in contact with a positioning nut (16) through a bearing (15), and the positioning nut (16) is in threaded connection with a valve seat body (12).

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