Ball valve for welding: design and application

Ball valves act as stop valves on external pipelines (gas and oil pipelines, pipelines for utility lines, pipelines in chemical explosive and fire hazardous industries, etc.). One of the varieties of the ball valve is a ball valve for welding.

It is used as a locking device in order to completely block the flow of circulating medium in the pipeline. Such an environment can be oil and its products, water, natural gas, air, alcohol products, other aggressive media.

This type of crane is characterized by the fact that it is connected to the pipeline by welding. The ball valve for welding does not have detachable parts (flanges, couplings, etc.), and this ensures maximum connection density and minimization of leaks in joints.

Classification

Ball valves for welding are classified according to the type of drive:

• Manual;
• Having electric drive (manufactured by special order taking into account the features of the pipeline);
• Manual with a reducer;
• With pneumatic drive (manufactured by special order taking into account the features of the pipeline).

Usually, a hand welded ball valve is used with relatively small overall dimensions of the passages, with low or medium pressure in the pipeline. If the pipeline pressure is above average, and the pipes themselves are large or medium-sized, it is better to use a crane with an electric drive or a crane with pneumatic drive.

Also, the ball valve for welding can be full-bore and incomplete (classified by the type of passage).

Production and construction of a ball valve

The components of the body of ball valves are made by welding (so that the connection is strong and reliable). A freely floating ball is sealed with PTFE saddles.

In production, the original technology is used. The principal feature of the devices is a steel, non-separable casing. During production, the locking mechanism is first assembled, and then inserted into the housing. The nipples are gently scalded.

The result is a non-separable construction that does not require maintenance.

The ball valve steel welded has a unique internal construction. In case of wear, this design compensates the process itself. This is facilitated by free-floating balls, which are located between springs that have a sealant. If one part wears out, the spring is unclenched and the structure is all still tightly connected. This ensures tightness for a long time.

Operation and maintenance

1. The ball valve for welding shall be operated at a temperature of not less than 30 ^о С.

2. The pressure in the pipeline can be 1.6 / 2.5 / 4 megapascals.

3. The circulating medium must also be of suitable temperature: the range is from -35 to +180 ^o C.

Regular maintenance and expensive maintenance of these devices are not needed. You can add only the seal on the rod by yourself. Design development does not provide for repair work or replacement of parts during the whole period of use.

Advantages and disadvantages of ball valves for welding

Pluses:

• Low specific gravity;
• Low cost;
• The tap opens quickly and easily;
• When using a tap, no stagnant zones are formed in the region where the liquid flows;
• Robust, reliable and simple construction;
• Hermetic overlapping of the liquid flow;
• This crane is installed in the most critical and difficult places of the pipeline;
• No maintenance required.

Disadvantages:

• Repair impossible;
• The crane can only be installed and changed with welding work;
• The possibility of a hydraulic impact when the crane is opened abruptly;
• Inconvenience in use because of the long lever of the crane shut-off (when working in tight conditions).