Design advantages for GZP Casted Trunnion Mounted BALL VALVE

① Fire safe, ② Antistatic, ③ Anti-blowout stem, ④ DIB or DBB Design ⑤ Low fugitive emission packing, ⑥Seat grease injector or Stem seleant injector , ⑦ Trunnion mounted desgin

Technical data
Design	API 6D, API 608, MSS-SP-72(BS5351),ASME B16.34
Pressures range	ANSI 150 ~ANSI 2500 ,PN10~PN420
Size range	2"-48" / DN50-DN1200
Body Material	A216 WCB	A352 LCB	A217 WC1	A217 WC6	A217 WC9	A217 C5	A351 CF8	A351 CF8M	A351 CF3	A351 CF3M
	NACE MR-01-75/NACE MR-01-03 Special Requirements
Face to face	API 6D, ASME B 16.10,
Fanged RF, FF, RTJ Ends	ASME B16.5, ASME B16.47 (Size 26’’~60’’)
	BS 4504,
Butt-Weld BW Ends	ASME B16.25 ,DIN 3239,
Temperature range	-196°~ 650°C
Design feature
Construction	Two or Three piece body and Welded body
Port	Full bore and Reduced bore
Ball Type	Solid ball
Stem	Blowout-proof stem, Anti-static,
Seat Sealing	Double Block and Bleed, Double Isolation and Bleed
Valve Operation	Gear,pneumatic,Hydraulic,Electric actuators.
	Locking devices,extended stem,etc
Fire Safe	API 607, API 6FA
Other design	Anti-static design, automatic pressure relief design, emergency grease injection design, drain valve, anti-corrosion design, anti-sulfur design etc
Inspection and Test
Visual Inspection	MSS SP-55
Material Inspection	PMI Test----Chemical Analysis
	HB Test---Hardness Test
	UT---Ultrasonic Test
	RT---Radio-graphic Test
	MT---Magnetic Test
	NDT Test Non-destructive
Dimension inspection	According to drawings
Valve Inspection and Test	API 598, API 6D, DIN 3230, EN12266

Cavity Pressure Relief Seat

Single Piston Effective (SPE) Design

Pd= Medium Pressure Pc= Body Cavity Pressure Ps= Spring Force

The medium pressure "Pd" and spring force "Ps" will push the valve seat to the ball and ensure the sealling tightness.

When the body cavity pressure increased to a certain value which over than the medium pressure plus spring force,

the cavity pressure "Pc" will push the seat apart from the ball, and the cavity pressure release automatically.

So this valve seat design can ensure the ball valve both side block and bleed function by medium pressure, as so called Double Block and Bleed (DBB Valves)

Double Piston Effective (DPE) Design

The medium pressure "Pd" and spring force "Ps" will push the valve seat to the ball and ensure the sealling tightness.

When the body cavity pressure increased to the pressure limitation, the cavity pressure will be released by the body vent bleeder (Safety Valve), so the valve cavity pressure will always be smaller than the Pd+Ps.

This valve seat desgin can ensure the ball valve both side isolated and block, as so-called Double Isolation and Block (DIB Valves)

Structure：2 pieces or 3 pieces body

High shut-off sealing mechanism and low torque operation

Block and bleed function

Self-cavity pressure relief

Fire safe design

Blow out proof stem construction

Anti-static design

Locking device (for lever handle operation}

ISO 5211 actuator mounting

Emergency grease injection (option)

Construction

The first difference between floating and trunnion mounted ball valves is in the way the valve is constructed. In floating ball valves the ball is only connected to the stem from one end whereas the other end is free. The ball is free to float inside the valve. In trunnion mounted ball valve, the ball is connected to the stem on one end and to another shaft called the trunnion on the other end. The ball is held firmly in place and can only rotate as the stem moves. You can easily distinguish between the two valves when you look at them as the trunnion mounted ball will have an added shaft at the bottom.

Type of Seats

In floating ball valves, the seats are usually made of elastomeric material. An elastomer is a polymer with viscoelasticity (both viscosity and elasticity). This soft material helps cushion the pressure from the onstream that pushes the ball to the seats. The seats in the valve directly manage all the pressure from the onstream. The seats in a floating ball valve have additional seal rings as well since they have to manage all the pressure. In trunnion mounted ball valve the seats are spring-loaded. Any additional pressure is managed by the stem and the trunnion.

Sealing Function

Floating and trunnion mounted ball valves both provide shut-off but have different sealing functions.

When floating ball valves are closed, the onstream pressure forces the upstream seat and the ball to the downstream seat forming a seal.

In , the onstream pressure activates the spring-loaded seats and they move towards the ball sealing the valve.

So the main difference in their sealing function is that, in trunnion mounted ball valves the ball does not have free movement and it can only rotate as the stem moves while In floating ball valves, the ball is free to rotate as well as move sideways.

Application

Floating ball valves are more suited for medium and low-pressure applications. They usually have smaller diameters and only provide seal only from the downstream side. Floating ball valves are suitable for mediums like liquids and gasses. Trunnion mounted ball valves are suited for larger, high-pressure applications. Since the seats move towards the ball, the valve seals from both the upstream and downstream end. Trunnion mounted ball valves can be used with liquids, gasses, as well as slurry mediums.

Added Features

In floating ball valves the seats need a separate mechanism for releasing additional pressure. This is the reason why they are not suited for high-pressure situations. However, the seats in trunnion mounted ball valve are self-relieving so any additional pressure is handled without the need for a separate mechanism. Trunnion mounted ball valves can also have abilities. This enables these valves to be used in critical high-pressure, high-temperature operations.

Conclusion

Floating ball valves have many advantages like small flow resistance, simple structure, good sealing performance, and being cost-effective for certain size and pressure. They are used widely in the oil and gas and water industry. They are available in a number of sizes and can be customized to suit your needs. We can add value-added features like oval safety handle, locking device, easy automation – pneumatic actuator, T-handle, extended bonnet for insulation, and more.

Features of cast trunnion ball valves are as follows:

1) Anti-fire safe design: API 6FA, API607

2) Anti-static device

The static-conduction spring is set between the stem and the ball, the stem and the body. Thus static electricity is conducted to ground and system safety is secured.

3) Anti-blow out design

4) Free leakage of body Sealed construction

The connective position of valve body and bonnet is double sealed by gasket and O-ring, on this base, such factors as fire, high temperature, shock and uneven opening or closing of the torque all can’t induce external leakage

5) Double block&bleed(DBB)

6) Emergency sealing

7) Automatic body cavity relief

When the body pressure going up un-normally as the unstable factor, the trunnion ball valve downstream seat will be pushed by un-normal pressure, and the release the un-normally pressure automatically, it doesn’t damage to the sealing of upstream seat.

8) The valve structure can be 2 pieces or 3 pieces.

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