What are the main factors affecting valve sealing? Archives

Butterfly valves are classified according to the sealing material, which can be divided into resilient seated butterfly valves and hard-sealed butterfly valves. There is a big difference in the scope of use between the two. The sealing pair of the resilient seated butterfly valve is composed of two parts. One side of the sealing pair is made of metal hard

U-type-flange-butterfly-valve-2

material and the other side is non-metal soft material. This combination makes the resilient seated butterfly valve have good sealing performance and can achieve zero leakage. However, compared with hard-sealed butterfly valves, resilient seated butterfly valves are not suitable for high temperature environments.

The resilient seated butterfly valve is small in size, light in weight, and has good sealing performance. It is responsible for switching on and off and controlling fluid flow in the pipeline system. It has a very wide range of applications in petroleum, chemical, metallurgical, and municipal construction industries.

The connection method of resilient seated butterfly valve is flange type and wafer type. In the process of operating and using resilient seated butterfly valve, some situations are often encountered. Let’s take a look at the factors that affect the operation and use of resilient seated butterfly valve.

In the valve market, rubber and PTFE are the most commonly used sealing materials for resilient seated butterfly valves. These sealing materials can maximize the sealing performance of resilient seatedbutterfly valves, regardless of whether it is a liquid or a gas medium. Zero leakage. However, because of the limitations of the structural characteristics of these sealing materials, the resilient seated butterfly valve cannot be used in high temperature, high pressure and high-wear circulation pipelines. If any of the above conditions appears in the pipeline, the resilient seated butterfly valve will malfunction and damage.
Fluorine lined butterfly valve-PTFE-WAFER (10)
The sealing ring of the resilient seated butterfly valve is fixed on the valve plate. When the butterfly plate of the butterfly valve is in the open position, the fluid medium in the pipeline will flush the sealing surface of the butterfly valve positively. Under the long-term erosion and corrosion of the fluid medium, the resilient seated material will wear out over time, which will affect the sealing performance of the resilient seated butterfly valve and cause leakage.

The factors that affect the operation of the resilient seated butterfly valve are the above two points. After the operator understands this information, he must pay attention to the use of the resilient seated butterfly valve, master the correct operation method of the resilient seated butterfly valve, and regularly perform maintenance and repairs to maximize the resilient seated butterfly valve Play a role and serve our industrial production.

TH Valve is a professional manufacturer of butterfly valve, gate valve, check valve, globe valve, knife gate valve, ball valve with API, JIS, DIN standard, used in Oil, Gas, Marine industry, Water supply and drainage, fire fighting, shipbuilding, water treatment and other systems, with Nominal Diameter of DN50 to DN1200, NBR/EPDM/VITON, Certificates & Approvals: DNV-GL, Lloyds, DNV, BV, API, ABS, CCS. Standards: EN 593, API609, API6D

Valve leakage is very common in daily life and industrial production, and the impact is very large. It will cause waste or bring danger to life. For example, the leakage of tap water valve will lead to serious consequences, such as the

ductile iron, DI, butterfly valve, manufacturer, center line, TH valve

chemical industry. Toxic, harmful, flammable, explosive and corrosive media leakage, etc., serious threats to personal safety, property safety and environmental pollution accidents. A valve that relies on external force to rotate and drive to open and close is designed with a sealing device. It is used to install a certain number of packing seals in the packing culvert to achieve a sealing effect, but how about the sealing? Leakage at the packing of the valve is one of the most prone to leakage failure in the valve, but the reasons are largely the following reasons.

1. The structure of the sealing pair

The structure of the sealing pair will change when the temperature or sealing force changes. Moreover, this change will affect and change the mutual force between the sealing pairs, thereby reducing the performance of the valve sealing. Therefore, when choosing a seal, be sure to choose a seal with elastic deformation. At the same time, pay attention to the width of the sealing surface. The reason is that the contact surfaces of the sealing pair cannot be completely matched. When the width of the sealing surface increases, the force required for sealing must be increased.

2. The specific pressure of the sealing surface

The specific pressure of the sealing surface affects the sealing performance of the valve and the service life of the valve. Therefore, the specific pressure of the sealing surface is also a very important factor. Under the same conditions, too much specific pressure will cause damage to the valve, but too little wine will cause valve leakage. Therefore, we need to fully consider the appropriateness of the specific pressure when designing.

3. The physical properties of the medium

The physical properties of the medium also affect the sealing performance of the valve. These physical properties include temperature, viscosity and surface hydrophilicity. The temperature change not only affects the slackness of the sealing pair and changes in the size of the parts, but also has an inseparable relationship with the viscosity of the gas. The gas viscosity increases or decreases as the temperature increases or decreases. Therefore, in order to reduce the influence of temperature on the sealing performance of the valve, when we design the sealing pair, we must design it into a valve with thermal compensation such as an elastic valve seat. Viscosity is related to the permeability of the fluid. When under the same conditions, the greater the viscosity, the smaller the permeability of the fluid. The hydrophilicity of the surface means that when there is a thin film on the metal surface, the thin film should be removed. Because this thin oil film will destroy the hydrophilicity of the surface and block the fluid channel.

4. The quality of the sealing pair

The quality of the sealing pair mainly refers to the selection, matching, and manufacturing accuracy of materials. For example, the valve disc and the sealing surface of the valve seat are very consistent, which can improve the sealing performance. The characteristic of many hoop waviness is its good labyrinth sealing performance.

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Factors Affecting the Operation and Use of resilient seated Butterfly Valves

What are the main factors affecting valve sealing?

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