The Design of the Welded Ball Valve (Part Two) - Dervos

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DERVOS VALVE CO.,LTD
Add: Unit , Channel Pearl Plaza, No.99 Yilan Road, 
Siming District, , Xiamen City, Fujian Province, China
: -592- 378
Fax: -592- 335
Mail:

Dervos Division: Forge Valves

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Product Usage

Fully Welded ball valves with integral welded valve bodies can effectively avoid external leakage. Welded ball valve is widely used in various fields, its superior quality and high performance stability is ordinary cast steel ball valve can not reach, all-welded ball valve service life is far greater than cast steel ball valve, all-welded ball valve is widely used in city gas, city heating, petrochemical, shipbuilding, steel, pressure regulating stations, power plants and other types of pipeline equipment.
Welded ball valves are generally available in blue, yellow, grey, black and other colours. Transmission methods include handle, worm gear, pneumatic, electric, etc.

Construction Characteristics

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• Fully welded housing;
• Trunnion mounted ball;
• Spring-loaded seat rings;
• Metallic or soft seals;  
• Double Block and Bleed”-version;
• Full or reduced bore;
• Flanged, welded or threaded connections;  
• Blow-out proof shaft;
• Shaft seals replaceable under full pressure in open and closed position;
• No static charging;
• Maintenance-free bearings;

Applicable Standards

Contact us to discuss your requirements of Welded Ball Valve Dn15-Dn150. Our experienced sales team can help you identify the options that best suit your needs.

• Design & Manufacture Conform with: API 6D/ ISO , ASME B16.34
• Connection Dimension Conforms with: ASME B16.25, DIN EN
• Fire Resistance Design Conforms with: API 607/ISO
• Inspection & Test Conforms with: API 6D, ISO , API 598
• Material Conforms with: ISO

Materials of parts 1 Body 12 Ball lubricating bearing 2 Left-right body 13 Screw 3 Ball 14 Bonnet gasket 4 Seat 15 Support cover 5 Sealing ring 16 Die holder 6 O-ring 17 Packing 7 Stem 18 Terminal pad 8 Seat grease injection valve 19 Spring pin 9 Spring 20 Flat key 10 straight pin 21 Stem gasket 11 Blow-down vavle 22 Static-free spring

Materials of parts Body 20#/A105/LF2/F304/F316/F304L/F316L/F11/F22/F51 Ball 20#+Hcr/A105+ENP/LF2+ENP/F304/F316/F304L/F316L/F51 Seat A105+ENP/LF2+ENP/F304/F316/F304L/F316L/F51 Stem 2Cr13/A105+ENP/LF2+ENP/F304/F316/F304L/F316L/F51 Sealing ring PTFE/NYLON/PEEK/TEFLON O-ring VITON/NBR Screw B7M/B8M/L7M/B16M Support cover A105+ENP/LF2+ENP/F304/F316/F304L/F316L/F51 Die holder A105+ENP/LF2+ENP/F304/F316/F304L/F316L/F51 Spring 17-4PH/17-7PH/Inconel Bearing 304+PTFE/316+PTFE Gaske Flexible graphite+304/PTFE

*Materials could be choosed according to customers’ requirement & working condition.


Fully welded ball valve performance

1. No maintenance, adjustment and lubrication, easy to install, reliable long-term operation at low running costs. The surface adopts spraying treatment technology, lustrous and beautiful, which has been in the leading level in China.
2. The surface is sprayed with plastic treatment technology, which has a beautiful lustre and is at the leading level in China. There will be no external leakage etc. The valve body is of welded construction, so the valve is light and easy to insulate.
3. The operating handle can be removed and installed in a different direction.
4. The valve seat is made up of a carbon fibre reinforced Teflon seal ring and a disc spring, so it is highly adaptable to changes in pressure and temperature and does not produce any leakage in the marked pressure and temperature range.
5. The processing of the ball is followed by an advanced computerised tester, so the ball is processed with high precision.
6. As the valve body material is the same as the pipe material, there will be no uneven stress and no deformation due to earthquakes and vehicles passing over the ground, and the pipe is resistant to ageing.
7. Integral fully welded, equal and variable diameter channels, fixed and floating balls, double piston effect sealing system, automatic injected sealant type bearings.
8. To prevent static electricity, the stem and ball and between the stem and stuffing box are equipped with steel balls and springs, which can keep all parts of the valve conductive to the valve body and let the current pass through the area, releasing static electricity. Not only to prevent fire, but also to prevent corrosion and to achieve a temporary cut-off for timely maintenance.
9. The stem anti-disengagement function is because the stem is affected by the pressure inside the valve and always generates a disengagement force so the stem is designed as an anti-disengagement structure.
10. Support with a low friction material thrust washer pushes the pressure against the stem so that the stem only acts as a torque transmitter.

Fully welded ball valve applications