The floating ball valve is an industrial valve that relies on medium pressure to achieve sealing. Its core feature is that the ball is in a floating state in the valve cavity. The following are its key features and technical points:
1. Core working principle
Floating sealing mechanism
The ball is connected by a single-side valve stem, without a lower support shaft to fix it; when closed, the medium pressure pushes the ball to move toward the outlet valve seat to form a forced one-way seal (outlet end seal).
Low-pressure conditions rely on the valve seat preload to seal, and the sealing effect increases with the increase of pressure under high-pressure conditions.
Opening and closing operation
The valve stem rotates 90° to drive the ball to rotate, realizing fast switching (the handle is in the open state when it is parallel to the pipeline).
2. Structural features
Support design
The ball is only fixed by the upper valve stem, and can be slightly displaced in the valve body along the medium flow direction to form a "floating" characteristic.
The lower part of the valve stem is equipped with a fly-out shoulder structure to prevent the valve stem from detaching under high-pressure conditions.
Sealing components
Valve seat material: Soft seals (such as PTFE, nylon) are used for clean media at room temperature; hard seals (stainless steel cladding) withstand high temperatures (≤550℃) or corrosive fluids.
Sealing form: The inlet and outlet valve seats clamp the ball, and the medium pressure pushes the ball to press the outlet valve seat, which is a single-sided forced seal.
Safety extension function
Fireproof design: After the soft seal burns out, the metal valve seat contacts the ball to form a secondary seal.
Anti-static device: The built-in spring of the valve stem guides the static electricity of the ball to prevent flammable media from igniting.
3. Application restrictions and scenarios
Applicable boundaries
Pressure range: Medium and low pressure systems (≤PN40/Class 600), ultra-high pressure can easily cause the valve seat to collapse.
Diameter limit: DN15–DN200 (larger diameters affect stability due to imbalanced sealing force).
Media type: Suitable for clean fluids such as water, oil, and gas; media containing particles or high viscosity should be selected with caution.
Typical Applications
General Industry: HVAC, water supply and drainage, low-pressure chemical pipelines.
Energy: Oil transmission branch lines, liquefied natural gas (LNG) medium and low pressure pipelines.
Summary: The floating ball valve drives the ball through the medium pressure to achieve one-way sealing at the outlet. It has a simple and compact structure and low cost. It is an economical solution for medium and low pressure small and medium diameter pipelines. Its fireproof and anti-static design expands industrial safety.
