The top entry ball valves are the valves that assemble the ball from the top end. It’s quite similar to a globe valve that has a body and a cap, except that the trim portion uses a ball type. It consists of a single entity. Typically, the top entry ball valves are made of cast metal. Since it is made from casting, certain additional NDE tests would be required to ensure that there is no defect in the casting process. Top input ball valves are commonly used in applications requiring limited disassembly for in-line maintenance of their internal components. It is also very common to use high-pressure ball valve inputs that need constant maintenance such as HIPPS (High Integrity Pressure Protection System) valves, etc. The benefit of the Top Entry Ball Valve is its design that allows a limited thread interaction such that the potential leakage path can also be minimized.
What is Top Entry Ball Valve?
Ball valves are commonly used in oil and gas pipelines as well as in oil, refining, petrochemical, chemical, chemical, metallurgical, electrical, nuclear, food, and paper machinery.
Due to the distinctive nature of the environmental conditions and operating conditions of the process, a typical ball valve is not sufficient and the system demands high performance. Using the top entry structure, it is not needed to remove the ball valve from the line when the seat is serviced or replaced, so it is easy to check and maintain the ball valve.
In general, the top entry configuration changes the location of the seat with a wedge or a threaded seat on the outside. The external wedge will, however, improve the exterior leakage point and decrease sealing efficiency, whilst the threaded seat will be quickly destroyed in the big diameter valve and the service life will be reduced. In view of the above conditions, a consistent top entry structure is designed in such a way that the valve seat consists of a V-shaped outer circle, which is developed to be angled to the contact portion of the control rod, reducing the stress on the control rod and the contact surface of the seat valve to maximize the service life effect. In addition, the geometry of the V-shaped outer circle makes it possible for the valve seat to be separated from the valve body when the valve seat is removed.
How does Top Entry Ball Valve Works?
Ball Valves have a ball that is supported at the bottom by a trunnion. When the bore is positioned in the direction of the conduit, the valve is in an open position, letting the fluid flow in. The stem starts to go down, and because of the channels machined on it, it twists 90°, causing the ball to turn the same. Then some of the channels are machined straight, and the stem can’t just go down.
In this case, owing to the angled surface, the stem drives the ball to the bottom trunnion and the seat. The ball only hits the seat in this position, and there is no pressure during the rest of the movement.
Top Entry Ball Valve comes in two main configurations:
Full Bore: The size of the trim is the same for the conduit. In this case, the valve is ideal for pigging.
Reduced Bore: The height of the trim is less than the size of the pipeline.
Types of Top Entry Ball Valve.
Top Entry Trunnion Mounted Ball Valve is specially engineered and built for low operating torque and fast maintenance. The one-piece heavy-duty body allows easy access to the stem and ball for on-site repairs. Top Entry Trunnion Ball Valves are available in a variety of configurations of flanged or welded end links of various sizes. Standard features of the Top Entry Ball Valve include Double Block & Bleed, Fire Safe Design, Emergency Sealant Injection, ISO Mounting Pad also depends on manufacturers. Extended stem/bonnet for underground operation is also a standard alternative provided by Top Entry Trunnion Ball Valve.
Top Entry Floating Ball Valves are mainly used for fluid control purposes in steam, boiling and other general industrial system uses. The top entry floating ball valve is a valve with a ball floating within the valve body, drifting towards the downstream side and pressing firmly against the seat under medium pressure to guarantee seal reliability. It has a simple structure, good sealing capacity, but the seat material is expected to accommodate as the sealing pressure is borne by the seat ring.
What are the Benefits and Features of Top Entry Ball Valve?
TOP ENTRY BALL VALVE is primarily used in pipeline and industrial systems and has a top entry and line maintenance feature. It has many benefits, such as low fluid resistance, simple design, compact volume, lightweight, reliable salting, ease of repair and control, open and close easily, as well as start and closes flexibly.
Its key distinction from the standard ball valve is that it can be maintained on the pipeline even without disassembly from the pipeline. The back seat configuration is adopted for the seat and the back part of the seat holder is obliquely angled to avoid impurity from impacting the back seat.
A one-piece body is used to ensure adequate strength and rigidity at the highest-rated operating pressure for the body. The internal components of the valve are specially engineered and chosen to ensure stability in all operating conditions. Sufficient margin wall thickness and adaptation to high-strength connective bolts are convenient for the maintenance of the valve and the ability to support pipe pressure.
Top Entry Ball Valve Vs Side Entry Ball Valve.
These ball valve concepts refer to the manner in which the valve ball and its internal components may be reached, either from the side of the valve or from the top of the valve (top entry).
The top entry design is used when repeated inline maintenance operations are required on the valve. This is due to the fact that the top entry ball valves provide quicker and faster access to the ball and valve trim relative to the side entry valves that need more repair time and space for the same operations.
The two Ball Valve design can be distinguished as follows:
Top entry ball valves are normally manufactured with cast steel bodies; while side ball entry valves are constructed with (strong) fabricated steel bodies.
Top entry ball valves include a monolithic design (made of one piece); and side entry valves are made of two or three pieces of assembly.
Top entry ball valves need more non-destructive testing than side entry ball valve due to their castings; side entry valves are simpler to install and assemble than the top entry, which takes a long time of training and workmanship to function properly
Top entrance ball valves are usually more costly than side entrance valves and have longer lead times attributed to the casting operations used to produce the body.
Summary:
Top Entry Ball Valves are mainly used where there is frequent maintenance is required for the valve and the seat, it provides ease of access for maintenance and repairs as the ball and the seat inside the valve can be maintained from the top of the valve and without dismantling the whole valve from the pipeline. Ntgd valve is experienced Top Entry Ball Valve Manufacturer, please feel free to contact us if you have any question.
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