The compact style ball valve is a floating ball valve with a seat carrier design. This seat carrier design is completely different from the traditional floating ball valve seat design. In the compact style floating ball valve, the seat carrier design, has overcome the challenges of low pressure positive shut-off and high operating torques.
By using multiple bearing surfaces, the floating compact ball valve design is able to deal with many areas of friction, that contribute to the overall operating torque of the valve. The compact floater also incorporates a stem bearing that utilizes a step on the bearing, that acts as an axial bearing, when installed into the bonnet, which prevents the stem from cantilevering. Testing has shown that up to 50% of the overall valve torque can be found in the stem and bonnet area of the valve.
Ball / Seat interface
The ball / seat cross section ratio will remain the same even as the valve bore sizes increase. Compared to standard floating ball valves the cross section area is much larger spreading the load to an larger area and reducing friction.
In this design, the seat carrier acts as an internal bypass mechanism that equalizes pressure at the moment the valve is opened, also reducing the operating torque.
Low pressure sealing
The seat assembly with the seat carrier is energized like the trunnion valve but with an elastomeric L- seal. The seat material selection is not like traditional floating ball valves that use PTFE but an Acetal co-polymer or Peek with an elastic memory.
The floating compact ball valve seat design will seal in the low pressure applications, on the inner diameter of the seat insert, creating a line seal and sealing bubble tight, even in Helium gas testing.
In a High pressure differential application the ball is pushed in the seat (the floating principle) pushing the ball into the downstream seat will follow the full geometry of the seat insert, creating a very large ball / seat interface. This large ball / seat cross section is the difference between the soft seated API 6D trunnion ball valves and the compact floating ball valve design, that makes it possible to use this valve in unprocessed upstream fluid applications.
The compact style floating ball & seat interface is larger than any other seat design and makes this valve more tolerant of abrasive fl ow media. This valve is widely used in applications where other ball valves are not even considered, such as upstream manifolds and fracking service.
The Compact style valve is supplied together with the bevel for weld end connections. At first glance, the valve looks like a butt-weld valve. In fact the valve design has eliminated the companion flanges and welds directly to the pipe. This also offers a significant cost and weight savings to this floating compact valve design.
Just like with the flexible bore sizes, this design is an engineered item. It can be supplied to meet any material specifications that are requested. The valve can be supplied in all possible material configurations.
The biggest savings are to be realized in the Space and Weight sectors and also the variety of applications, for which it is well suited. Its original application, for High Pressure Production Manifolds has not restricted it’s use to only Off shore applications, where space and weight are always of the utmost importance. In fact due to the uniqueness of the design, with bores based off of common pipe sizes and piping materials, custom bores sizes can even be offered for piggable service applications.