Which is better between a fully welded ball valve and a flanged ball valve

There are flange links and welded links, but some users will say which one is better. The technician will answer for you:

One: The flanged ball valve is more troublesome to process than the fully welded ball valve, and the material is also more and heavier than the welded one. The use cost is slightly more expensive than the welded one, and it is more convenient to replace.

Two: The fully welded ball valve body is made of a cast valve body and a forged valve body. The ball cushion is made of reinforced polytetrafluoroethylene. The valve stem adopts an explosion-proof design. Temperature range: -29-150°C. Fully welded ball valves are widely used in long-distance pipelines such as natural gas, petroleum, heat supply, chemical industry and thermoelectric pipe network.

1. Fully welded ball valve city gas: gas output pipeline, mainline and branch line supply pipeline, etc.

2. Fully welded ball valves (application fields: food, chemical industry, petroleum, electric power, etc.)

central heating: output pipelines, main lines, and branch lines of large heating equipment.

3. Fully welded ball valve heat exchanger: opening and closing of pipelines and circuits.

4. All-welded ball valve steel plant: various fluid pipelines, waste gas selective release pipelines, gas and heat supply pipelines, and fuel supply pipelines.

5: Fully welded ball valves are used in various industrial equipment: various heat treatment pipelines, and various industrial gas and heat pipelines.

The flat welding flange is a flange that is directly welded to the equipment or pipeline through the fillet weld. The structure is simple and the processing is convenient.

Its stress characteristics are between the integral flange and the loop flange. The flat welding flange is divided into plate flat welding flange and neck flat welding.

The flat welding flange is low in cost and short in the production cycle. It is more commonly used. A flange type is widely used in various fluid pipelines. Therefore, the requirements for construction time and construction safety are very high when constructing and maintaining gas supply pipelines and heating supply pipelines.

Fully welded ball valves can be directly buried underground. The use of engineering technology for construction can effectively reduce the space occupied by valve control, and greatly save construction costs and engineering time.

And it can prevent the danger of gas explosion, the welded ball valve is a very safe valve.

1. Fully welded ball valve welded structure:

Fully welded ball valves Most of the large-diameter ball valves used in domestic production are split three-piece structures, and the parts are connected by bolts.

Compared with the three-piece ball valve, the wall thickness of the welded ball valve forging can be made very thin under the same strength. The weight of the valve can be reduced by a quarter, while the resistance to pipe bending and extrusion is increased; due to the elimination of the valve body flange and bolts.

Reduced form factor. The same call also eliminates a potential leaky channel. In addition, the internal curve of the welded structure of the valve body is smooth. It maintains the lubricated connection with the pipeline without dead ends, and the fluidity of the medium is good.

2. Fully welded ball valve frame shaft fixed ball design

Fully welded ball valves can be divided into two types: fixed ball and floating ball according to the ball form. Domestic products generally adopt a floating ball structure. Under the pressure of the medium, the ball is pressed tightly on the sealing surface of the outlet end to achieve the purpose of sealing. Once the pressure difference between the inlet and outlet of the valve body is large, it is often difficult to open due to the large torque.

The fully welded ball valve adopts a particularly high-strength satin steel stem, which is supported by stainless steel bearings to rotate smoothly and accurately. Since the pivotally supported valve stem can absorb the thrust generated by the pipeline medium pressure and reduce the friction between the valve ball and the valve seat, even under the full pressure difference, the torque required to operate the concave door is still very low, and the ball valve can be opened and closed freely.

3. Fully welded ball valve stem anti-flying structure:

Fully welded ball valve When the medium passes through the valve, the pressure in the cavity of the valve body may push the valve stem out.

In order to prevent this from happening, a boss structure is provided at the lower part of the valve stem.

In this way, even if the packing and thrust bearing are burned or damaged by other reasons in case of fire, the medium pressure in the valve body will make the valve stem boss and the valve body seal tightly in contact, preventing a large amount of medium from leaking from the damaged packing.

4. Fully welded ball valve anti-static device

Fully welded ball valve When the valve is operated, due to the friction between the ball and the non-metallic material seat such as PTFE, static charges will be generated and accumulated on the ball. In order to prevent static sparks, an anti-static device is specially installed on the valve to discharge the generated static electricity.

5. Fully welded ball valve fireproof structure

Fully welded ball valve (application fields: food, chemical industry, petroleum, electric power, etc.) The seat of the floating ball valve adopts a unique structure. When a fire breaks out and the non-metallic sealing surface material is burned, the metal ring uses the elastic force of the spring to push the seat and the ball to seal.  thereby preventing the spread of fire and the outflow of media.

6. The middle flange of the fully welded ball valve has no leakage structure

The connection between the full-welded ball valve body and the left body is sealed by a gasket. In order to prevent seal leakage caused by factors such as fire, high temperature or vibration, it is specially designed so that the valve body and the left body are in metal contact to form a sealing method. Lan, to ensure no leakage.

7. Fully welded ball valve automatic pressure relief structure

Fully welded ball valve When the medium trapped in the middle cavity of the valve (function: cut-off, diversion, pressure stabilization, diversion, etc.) changes due to factors such as the pressure of the pipeline system or the temperature of the medium, and the pressure in the middle cavity rises abnormally, the middle cavity The medium can rely on its own thrust to push the valve seat to automatically release pressure, thus ensuring the safety of the valve.