What is an Eccentric Hemispherical Valve? A Comprehensive Overview

Introduction

The eccentric semi-ball valve is a valve with the structural point that the valve ball is eccentrically installed in the center of the valve body, and the inflow of the medium is controlled by rotating the valve ball. The eccentric semi-ball valve is substantially used for the control of special fluids  similar as high- density media, media containing solid  patches, media that are easy to solidify, precipitate, and solidify.

The eccentric semi-ball valve is suitable for media control in the fields of chemical, petroleum,  medicinal, and food, especially under special working conditions similar as high temperature and high pressure, strong erosion, high density, and containing solid patches.

Description and Basic generalities

What’s an Eccentric Hemispherical valve?

The eccentric hemispherical valve is a fairly new type of ball valve. Its core design lies in the eccentric placement of the ball and the valve seat. This putatively subtle layout adaptation actually contains profound engineering wisdom. The eccentric design makes the ball have a unique movement line during the opening and ending process, which reduces mechanical  hindrance and  disunion loss compared to the concentric structure.

The structural features of the eccentric hemispherical valve substantially include the following aspects： 

1. valve body：The valve body of the eccentric hemispherical valve generally adopts a globular structure, one side of the sphere is hemispherical and the other side is indirect.The hemispherical side is the bay of the valve, and the indirect side is the outlet of the valve.

2. Hemispherical valve core：The hemispherical valve core is the core element of the eccentric hemispherical valve, and its shape is analogous to a hemispherical coliseum. One side of the hemispherical valve core is convex and the other side is hollow. The convex side corresponds to the hemispherical side of the valve body, and the hollow side corresponds to the indirect side of the valve body.

3. Transmission device：The transmission device of the eccentric semi-ball valve generally adopts homemade, electric or curvaceous transmission device. Homemade transmission bias generally borrow hand bus or handles, electric transmission bias generally borrow motors and reducers, and curvaceous transmission bias generally borrow curvaceous selectors.

4. Sealing structure：The sealing structure of the eccentric semi-ball valve generally adopts soft seals or essence seals. Soft seals generally borrow accoutrements similar as rubber or polytetrafluoroethylene, and essence seals generally borrow accoutrements similar as pristine  sword or titanium amalgamation.

Characteristics of Eccentric Hemispherical valves 

Compact Structure

It adopts direct current design, with small fluid resistance, simple structure, small size, light weight and wide operation range.

The eccentric hemispherical valve has compact structure and light weight, and is suitable for occasions with conditions on valve installation space.

Excellent Sealing Performance

Its structure adopts the eccentric wedge tensing principle to achieve the purpose of gate  tensing, adaptation and closing through the transmission medium. The sealing brace is a essence ring with a hard face contact seal. When the double eccentric structure is opened, the ball is located in the ball storehouse chamber, the inflow section is large, and the valve isn’t washed. When closed, the ball isn’t washed. When opened, the  globular  face of the ball gradationally moves along the valve seat, effectively removing the scaling handicap to achieve dependable sealing.

Wear- resistant and erosion- resistant accoutrements

Eccentric ball valves are generally made of wear and tear- resistant and erosion- resistant accoutrements, and the ball and valve seat are largely matched.

Not easy to blunder under high temperature and high pressure conditions, the eccentric ball  valve can still maintain good sealing performance and isn’t easy to blunder.

High temperature and high pressure capacity

The eccentric ball valve can manage with high temperature and high pressure conditions, and is suitable for places with medium temperatures up to 600℃ and pressures up to 42MPa.

Low Fluid Resistance

Low resistance measure

The eccentric ball valve has low fluid resistance, and its resistance measure is equal to that of a pipe section of the same length, which helps to reduce energy consumption.

Good inflow performance

When completely open, the cross-sectional areas of the valve body channel, ball channel and connecting pipe are harmonious, forming a straight line connection, and the fluid flows easily in the valve.

Easy Operation

Quick opening and ending The eccentric ball valve can be completely opened or closed by rotating 90°, which is accessible and quick to operate.

Simple conservation:

The eccentric ball valve has a simple structure, and the sealing ring is generally portable, which is accessible to disassemble and replace, and is easy to repair and maintain.

Long Service Life

Automatic compensation for wear and tear. The eccentric structure of the sealing face of the eccentric ball valve enables the globular face to automatically compensate for wear and tear, thereby extending the service life of the valve.

Wear-resistant treatment The sealing material of some eccentric ball valves has experienced special wear and tear- resistant treatment, with high  face hardness, which further improves the wear and tear resistance of the  valve.

Working Principle

The working principle of the eccentric hemispherical valve is to control the inflow and pressure of the fluid by rotating the hemispherical valve core. Specifically, the eccentric hemispherical valve adopts an eccentric crankshaft design, which makes the center line of the ball crown diverge from the center line of the valve inflow channel by an eccentric distance. When the valve is opened, the crankshaft rotates a veritably small angle, and the ball crown will leave the valve seat, and the ball crown and the valve seat will no longer communicate; again, during the valve  ending process, the ball crown will only communicate the valve seat at the moment of ending. In this way, the valve seat and the ball crown don’t rub against each other during the opening or  ending process of the valve, icing the sealing and service life of the valve.

Application Fields

Eccentric semi-ball valves are extensively used in numerous diligence similar as petroleum, chemical, electric power, external water treatment, food and medicinal.

In the oil painting and gas assiduity, eccentric semi-ball valves can repel high temperature, high pressure and harsh sharp terrain, and are suitable for oil painting and gas channels;

In the chemical assiduity, eccentric semi-ball valves can be used to control the inflow of sharp media;

In the power assiduity, eccentric semi-ball valves are frequently used in the cooling systems of thermal power and nuclear power shops;

In the external water treatment assiduity, eccentric semi-ball valves are extensively used in civic water force, sewage treatment and other affiliated diligence;

In the food and pharmaceutical assiduity, eccentric semi-ball valves have come important  valves in crucial links due to their excellent sealing performance and material parcels.

Comparison with Other valves

Traditional Ball Valves

1. Low inflow resistance of the fluid

The design of the eccentric hemispherical valve makes the internal inflow channel of the valve smooth, and the resistance of the fluid when passing through the valve is small, which can ameliorate the inflow capacity.

2. Good sealing

The ball of the eccentric hemispherical valve adopts a design that deviates from the center of the ball, so that the sealing face between the ball shell and the ball forms a conical seal, which makes the valve have better sealing performance and can insure that the valve is leak- evidence.

3. Strong wear and tear resistance

The sealing face of the eccentric hemispherical valve is generally made of carbide material, which has good wear and tear resistance and can be used for a long time under high-speed inflow media without easy wear and tear of the sealing face.

4. Good erosion resistance

The sealing face material of the eccentric hemispherical valve can elect applicable accoutrements  according to different use conditions, can acclimatize to the cattiness of different media, and has good erosion resistance.

Globe valves and Gate valves 

Small opening necklace

Due to the design of the eccentric hemispherical valve, only the contact force between the ball and the sealing  face needs to be overcome when opening, so the opening necklace is small and the operation is accessible.

Small inflow resistance

The ball of the valve core only connections the valve seat within the semicircle. There’s no contact face when the fluid passes through the valve. There’s contact only when it’s completely opened or closed.

Selection and Installation Considerations

When installing valves, pay attention to the following

1. Select the applicable valve type and specification to meet specific operation conditions.

2. insure that the valve is installed in the correct position and direction and install it according to the inflow direction mark of the valve.

3. Before installing the valve, a primary examination should be carried out, including checking the sealing performance, material and working pressure of the valve.

4. Before installing the valve, insure that the channel is clean and remove any contaminations that may beget blockage or damage.

5. Use applicable tools and accessories, similar as flanges, bolts and gaskets, to insure that the connection between the valve and the channel is firm to help leakage.

6. According to the installation instructions of the valve or the guidance handed by the manufacturer, rightly install and acclimate the operating device of the valve, similar as hand wheel, electric device or curvaceous device.

7. After completing the installation of the valve, perform a leak test and a functional test to  insure that the valve is working duly.

8. For valves that bear frequent conservation, regular examination and cleaning should be included to maintain their normal operation and extend their service life.

Conservation and Overhaul

In order to insure the normal operation of the eccentric hemispheric valve and extend its service life, it needs to be regularly maintained and serviced. The following are some common  conservation and service measures

Regular examination: Check the appearance, connection corridor and sealing shells of the valve for damage or leakage.

Drawing and lubrication: Clean the dirt and contaminations outside and outside the valve regularly, and keep the oiled corridor waxed.

Replace the seal: If the valve is set up to be oohing, the seal should be checked and replaced in time.

Avoid inordinate force: When operating the valve, avoid inordinate force or inordinate gyration of the valve stem to avoid damage to the internal corridor of the valve or failure of the seal.

Conclusion

In summary, the eccentric semi-ball valve has good inflow regulation performance and can achieve precise inflow control. Due to the eccentric design of the valve ball, the opening and  ending necklace of the valve is small, which can reduce the difficulty and fatigue of operation. The sealing performance of the eccentric semi-ball valve is good and can effectively help fluid leakage. Due to the simple structure of the valve, conservation and form are fairly accessible. The eccentric semi-ball valve is suitable for fluid control under high temperature, high pressure, strong  erosion and other working conditions, and has a wide range of operation prospects.

With the nonstop development of fluid control technology, eccentric semi-ball valves are also constantly instituting and perfecting. In the future, eccentric semi-ball valves will develop in the direction of advanced performance, more intelligent and more environmentally friendly. For  illustration, by espousing new accoutrements, optimizing structural design, introducing intelligent control systems and other means, the pressure resistance, temperature resistance, erosion resistance and other parcels of eccentric semi-ball valves can be bettered; at the same time, by introducing Internet of effects technology, realizing remote monitoring and intelligent control and other functions, the intelligence position of eccentric semi-ball valves can be bettered; in addition, by espousing environmentally friendly accoutrements and low- energy consumption design and other measures, the impact of eccentric semi-ball valves on the terrain during use can be reduced.

In short, as an important fluid control device, the eccentric semi-ball valve plays an important  part in colorful fields. With the nonstop advancement of technology and the nonstop expansion of operation fields, the eccentric semi-ball valve will continue to develop and introduce, bringing  further possibilities and challenges to the field of fluid control.