How to Inspect the Quality of Fully Welded Ball Valves?

Buried fully welded ball valves have been widely used in a variety of fields. Although there are many buried fully welded ball valves on the current valve market, the quality of them is greatly different. Today, Baltic shares some methods of judging whether fully welded ball valves have good quality or not with you.

First, we can inspect the quality of buried fully welded ball valves through strength tests. Weld high pressure pipe caps on the two side sleeves of the buried fully welded ball valve; open the valve to the 45 degree angles; inject water into the ball valve through the valve for the pressure test on the sleeve; increase the pressure to 1.5 times of the ball valve's nominal pressure and then keep the pressure for 15 minutes. If there is no leakage happening, the buried fully welded ball valve will be qualified.

Second, we can inspect the quality of buried fully welded ball valves through testing the leakproofness of buried fully welded ball valves. Close the buried fully welded ball valve first; inject the nitrogen through the valve for the pressure test on the sleeve until the pressure in the valve cavity rises to 1.1 times of the ball valve's nominal pressure; use a hose to connect the pressure release valve of the middle cavity with the water container and make the hose inserted 1cm in the water. If there are no bubbles produced within 5 minutes, the buried fully welded ball valve will be qualified.

Sealing structures and processing technologies of fully welded ball valves

Sealing structures
The elastic sealing surface of the fully welded ball valve adopts the anti-erosion design, which can absorb the energy from erosion through the deformation first, and then rebound the energy so as to reduce the action of erosion and wear and prolong the service life of the valve. The flange of the fully welded ball valve is connected with the gland of the upper valve stem through the welding connection.

Processing technologies
Fully welded ball valves are welded by automatic submerged arc welding machines, and the flanges and glands are welded automatically, which makes unified welding parameters, high welding efficiency as well as good welding quality obtained. The special processing technologies of balls and valve seats not only make valve seat components have high precision, but also make balls' rotary surfaces in contact have low roughness and high precision, ensuring the good sealing performance, the low torque, the long service lives and reliable operation of fully welded ball valves.