The Structural Advantages and Standards of Ball Valves

The Structural Advantages and Standards of Ball Valves


Items Names Structural advantages  Design Standards
1 Internally threaded  ball valves,
socket welded ball valves,
integral ball valves and split ball valves
1. Reduced bores or no reduced bores
2. Floating balls (supported by seats)
3. Anti-blow out stem
4. Internal threads, socket welding, butt welding (extended shell) ends
5. Anti-static and fire-resistant structure
 
BS 5351,
ISO 7121,
MSS-SP-72 and BS 5159
2 Wafer ball valves and integral side entry ball valves 1. Reduced bores or no reduced bores 2. Floating balls(supported by seats) or fixed balls (supported by shafts)
3. Anti-blow-out stem
4. Anti-static or fire-resistant structure
5. Flange ends
 
3 Side entry ball valves and integral top entry ball valves 1. Full bores or reduced bores
2. Floating balls (supported by seats) or fixed types (supported by shafts)
3. Anti-blow-out stem
4. Sliding valve seats or sealed cavity balls
5. Anti-static or fire-resistant structure
GB/T 12237
4 Trunnion ball valves 1. Full bores
2. Floating balls (shaft supports)
3. Flange connection for the shell and upper bonnet
4. Flange (RF, RTJ) and butt welding ends
5. Anti-static and fire-resistant structure
API 6D
5 One-piece ball valves 1. Straight-through or reduced bores
2. Forged steel or cast steel shells
3. The valve seat pressed by the internal thread
4. Anti-blow-out stem
5. Threaded connections
 
6 Two-piece ball valves 1. Full bores or reduced bores
2. Forged steel or cast steel left and right shells
3. The valve seat pressed by the internal thread
4. Anti-blow-out stem
5. Threaded connections
 
7 Ball valve with insulation jackets 1. Full bores or reduced bores
2. Forged steel or cast steel shells 
3. PTFE valve seats for floating balls
4. The valve stem is sealed with packing, and the packing sleeve and pressure plate are used to press and seal.
5. Flange structure
6. The shell part is equipped with a thermal insulation jacket.
 
8 Metal-sealed pneumatic top entry ball valves 1. Full bores or reduced bores
2. Casting chromium molybdenum steel shells and upper bonnets
3. Bolted flanges
4. Sealing rings and metal valve seats for the sealing of the flange
5. Butt-welding hard alloys for the sealing surfaces
6. Flange structure
API 6D and API 608
9 Oil-sealed trunnion ball valves 1. Full bores
2. Cast steel or forged steel left and right shells and spheres
3. O ring sealing for the left and right shells
4. Bolts for connecting the left and right shells
5. Grease nozzles provided at the sealing rings of both valve seats
6. A key for connecting valve stems and balls
7. Welding or flanges for connecting the pipeline
8. PTFE used for the sealing ring
API 6D and API 608
10 Floating ball valves with sliding seats 1. Full bores or reduced bores
2. Forged steel or cast steel left and right shells
3. Bolts for connecting the left and right shells and gaskets used for sealing
4. The seal rings of the left and right housings have a plane with an angle of 5, and the valve seat's seal ring can slide freely on the inclined plane with an angle of 5.
5. The valve stem is sealed with packing.
6. The adjusting screw at the bottom of the shell is also sealed with packing.
7. Flange connections

API 608
11 Trunnion ball valves with front seat sealing 1. Full bores
2. Cast steel or forged steel shells, upper bonnets and spheres
3. Top entry ball valve shells
4. The upper bonnet of the shell is connected by bolts.
5. The floating valve seat is adopted; PTFE is adopted for the sealing surface. The back of the valve seat is equipped with a spring, and the front valve seat shoulder is accurately calculated to ensure the sealing specific pressure of the inlet valve seat.
6. Flange or welding connections
API 6D and API 608
12 Trunnion ball valves with rear seat sealing 1. Full bores
2. Cast steel or forged steel shells, upper bonnets and spheres
3. Top entry ball valve shells
4. The upper bonnet of the shell is connected by bolts.
5. The floating valve seat is adopted; PTFE is adopted for the sealing surface. The back of the valve seat is equipped with a spring, and the front valve seat shoulder is accurately calculated to ensure the sealing specific pressure of the inlet valve seat.
6. Flange or welding connections
API 6D
and API 608
13 Three-piece trunnion ball valves 1. Full bores
2. Cast steel or forged steel middle bodies, left and right shells and spheres
3. The middle body, the left shell and the right shell are connected by bolts, and the gasket is used for sealing.
4. The ball is fixed by upper and lower stems.
5. There is a disc spring behind the seat's sealing ring or at the shoulder.
6. The valve seat is made of PTFE or metal.
7. Bearings are provided at the upper and lower stems, and the upper and lower stems are sealed with O-rings.
8. Flange or welding connections
API 6D
and API 608
14 Top entry trunnion ball valves 1. Full bores
2. Cast steel or forged steel shells, upper bonnets and spheres
3. The shell and upper bonnet are connected by bolts, and gaskets are used to ensure sealing.
API 6D
and API 608
15 Fully welded trunnion ball valves 1. Full bores
2. Cast steel or forged steel left and right shells
3. After the whole valve is assembled and passed the inspection, the left and right shells are welded together again.
4. The ball is fixed by upper and lower stems.
5. The upper stem is sealed with O-rings; the lower stem is sealed with gaskets, and then welded. Bearings are provided at the upper and lower stems.
6. Disc springs are provided on the back and shoulders of the valve seat, and the seat’s sealing ring is made of PTFE or metal.
7. Flange or welding connections
API 6D
and API 608
16 Fully welded floating ball valves 1. Full bores or reduced bores
2. The shell and sphere are formed by steel plates. Valve seats and stuffing box bodies are made by round steel turning, and flanges are made of forged steel.
3. The valve seat’s sealing ring is made of polytetrafluoroethylene.
4. The valve stem adopts anti-blow-out structure.
5. After the overall assembly and inspection, the welding is performed. 
API 608
17 Screw rod type lifting stem ball valves 1. Full bores or reduced bores
2. Spherical top entry shells
3. The shell and upper bonnet are connected by bolts.
4. Cast steel or forged steel shells, upper bonnets and spheres
5. The butt welding hard alloys is adopted for valve seats, and the contact surface of the ball and valve seat is welded with hard alloys.
6. The sphere adopts a fixed ball.
7. There is a spiral flat on the bottom of the valve stem, so that the valve stem lifts and drives the ball to leave the valve seat and rotates 90°,  then presses against the valve seat.
8. Flange, clamping or welding connections
API 6D
and API 608
18 Guide trough lift rod ball valve orbital ball valve

 
1. Full bores or reduced bores
2. Spherical top entry shells
3. The shell and upper bonnet are connected by bolts.
4. The shell, upper bonnet and sphere are made of cast steel or forged steel.
5. The valve seat adopts metal butt welding hard alloys, and the contact surface of the ball and the valve seat is welded with hard alloys.
6. The sphere adopts a fixed ball.
7. There is an S-shaped guide groove on the valve stem, and the guide pin cooperates with the guide groove to drive the ball out of the valve seat when the valve stem is raised and lowered, and then rotate 90°to press against the valve seat.
8. Flange or welding connections
API 6D
and API 608