Solid ball valve design?

[ENPMAT]

Dears,
Could any one explain the meaning of "Solid ball valve" ? and if the ball valve is not constructed with solid ball what are the acceptable alternatives.

Regrads,
ENPMAT

 

[gerhardl]

A 'solid' ball valve is a ballvalve where the ball is machined from 100 compact casting or barstock. The opposite is a 'hollow ball' where the ball is constructed with an inside hollow, usually by two metal spheric halves joined together, with or without inside walls or ribs as reinforcement.

The hollow-ball concept is used to save weight and/or money in materials and machining.

If there is a choice between solid and hollow ball for the same application, the solid ball is normally considered as the 'best cost/lifetime' solution. Reasons given are less risk for construction, wear, material and fabrication failure over time. The difference between the two could however be from 'practically insignificant' to 'very high', all depending on quality, QA for product and application circumstances. Note: for some very large constructions solid ball would not be practical.

(For this answer 'ball-valves' where only a part of a 100% spherical shell is used in construction is not included as full 'hollow ball'. Typical sample would be 'V-port ball valve' for special regulating purposes)

Best advice to you could probably be given to you if you present your application to a factory that produces both solutions.

 

[ENPMAT]

Thanks gerhardl,
So "solid ball" does not mean that the ball is fabricated from soldi materials such as Tungsten carbides or St n°6.

Regards,

 

[gerhardl]

Any solid ball or hollow ball could have an outer layer of some other material as protective or more corrosive or wear resistant surface. The material could be welded on an machined, or deposited as top layer in a number of other ways.

 

[bcd]

Just to confirm that Gerhardl, as usual, is absolutely correct.

Solid ball means the part is made from a solid sphere and a hole is drilled through to make a the flow path. So between the flow port and the outer surface of the sphere, the ball is solid.

Hollow ball is when the inside of the sphere is "hollow" There is a certain thickness to the shell to give it strength, but unless you weld in a piece of pipe, the flow port through the ball will not be circular.


Hollow balls are used to save weight and cost, and are only useful in large valves where the weight of he ball becoms significant. The concern with hollow balls is the strength under pressure when valve is shut, and more importantly, the strength of the ball / stem connection for opening and closing the valve.

Both solid and hollow balls can be made from one material, or a material that is coated with hard facigns such as tungsten carbides.