Sanitary Ball Valve Overview

January 17, 2014
Ball Valve Sketch

Ball Valve Sketch

This is the second of our posts giving basic overviews of the various sanitary valves commercially available on the market.   Today we going to discuss the sanitary ball valve

The sanitary ball valve is a valve with a spherical disc, the part of the valve which controls the flow through it.  The sphere has a hole, or port, through the middle so that when the port is in line with both ends of the valve, flow will occur. When the valve is closed, the hole is perpendicular to the ends of the valve, and flow is blocked.  The handle or lever will be in line with the port position letting you see the valve’s position.  The ball valve along with the butterfly valve and plug valve, are part of the family of quarter turn valves.

Using ball valves in sanitary applications has some pluses and minuses.  Perhaps the greatest benefit of using sanitary ball valves is that they usually work to achieve perfect shutoff even after years of disuse.  They are therefore an excellent choice for shutoff applications and are often preferred to sanitary butterfly valves, diaphragm valves or seat valves.  They do not offer the fine control that may be necessary in throttling applications but are sometimes used for this purpose.  The other big advantage ball valves have is that they are the highest pressure rated sanitary valves on the market.

Principles of Operation
Sanitary ball valves, as the name implies, have a ball with a hole drilled through the center swivel mounted with the valve body.  When the
hole in the ball is oriented in the same direction as the pipe, this will result in full flow rate.  As the hole in the ball is oriented away from the direction of the pipe, the flow rate will be restricted and finally cut off completely when the hole is oriented 90 degrees to the pipe direction.

Cutaway of a Typical 3 Piece Sanitary Ball Valve

Cutaway of a Typical 3 Piece Sanitary Ball Valve

Typical Pressure Ratings
Size                       Rating
0.5”-2”                 1000 PSI
2.5”-4”                 800 PSI

Like sanitary butterfly valves, most sanitary ball valves can be highly automated.  Ball valves are offered with stainless steel actuators for all sizes.  There are different switch packages available which to mount to the actuators.  Double rack and pinion pneumatic actuators are the standard for ball valves, because they are ¼ turn valves.  Also the same as the butterfly valves, ball valves have a large offering of different ¼ turn actuators on the market.

Other Features and Benefits
Many different manufacturers offer their version of a ball valve although the operational features are very similar.  In the market of ball valves there are many different alternative choices so that potential customers are easily able to find another choice.  For this reason it is important to decipher a customer’s needs for the application at hand.  This will make it possible to choose the one that will be a quality performer at a good price.

Like the butterfly valve, a ball valve is available in 316 as well as AL6XN and Titianium material.  This type of construction material is not available with all manufacturers, as well as, it can be difficult to find MTRs and C of C’s to go along with the desired valve.  There are multiple handle styles that are offered with the ball valve as well, such as, pull stop with a locking mechanism and trigger handles.  Ball valves have the luxury of coming with many different connection styles in order to be able to fit into a customized sanitation process line.

Are Sanitary Ball Valves Really Clean?
As we discussed with the butterfly valve.  What is considered “sanitary” is relative to each end user.  The fact that sanitary ball valves are constructed with 316 stainless steel, have FDA approved elastomers and have Tri-clamp or tube OD buttweld ends puts them in the sanitary realm.  But you really cannot truly clean it in place.  Ball valves have cavities and crevices behind the ball that gather product when the valve in being actuated.  These areas do not get clean during CIP.  To truly clean the valve, you have to take it apart.  Even with newer designs of ball valves having FDA approved cavity fillers to help limit product build up on the inside of the vale it is inevitable that product will still accumulate around the outside of the ball and orifices.   Because of the sanitary ball valve do not carry the 3A rating.

Pluses                                                                              Minuses
High Pressure                                                                 Not easily CIPable
Steam able                                                                      Not most clean
No pressure drop                                                           Product gathers on ball and inner cavity
Automated with commercial actuators

This is our 2 cents worth about the sanitary ball valve.  Hopefully you found this informational and mildly interesting.  If there are any questions about these or any other valves please contact us via the website or give us a call at 800-800-8464.