What Are The Three Types Of Ball Valves?

According to the structure design and function characteristics of ball valve, ball valves is divided into three types: floating ball valves, fixed ball valves and elastic ball valves. Here's a breakdown:
1.Floating ball valves
Structural features
Sphere floating design: the sphere is fixed by the upper and lower stem only, is not mechanically bound, and can be moved slightly between the valve seats under moderate pressure.
Sealing mechanism: Dielectric pressure presses the ball to the outlet side valve seat, forming a one-way seal; when reverse pressure is applied, the ball is pressed to the inlet side seat, achieving a two-way seal.
Stem Design: The upper stem is connected to the actuator, while the lower stem acts only as a support to prevent the ball from shifting.
Performance advantages
Simple structure: few parts, low manufacturing cost, suitable for medium-small diameter (≤ 300).
Reliable sealing: Dielectric pressure can automatically compensate for the wear and tear of the sealing cover, prolonging the service life.
Convenience of operation: In low voltage condition, small opening and closing torque, suitable for frequent operation.
Typical application
Water treatment system: such as tap water pipes, sewage treatment plants, the use of two-way sealing characteristics to prevent backflow.
Low pressure gas pipe: such as outlet pipeline for air compressor, pressure ≤ 1.6 MPa.
Chemical industry: Pipeline for the transport of non-corrosive media such as alcohol and glycerin.
2. Trunnion installs ball valves
Structural features
Sphere fixation design: The sphere is rigidly connected by the the upper and lower trunnions and cannot be moved.
Sealing mechanism: Dielectric pressure is dispersed to the valve body through the stem, and the sealing pressure is controlled by the preload spring or dielectric pressure respectively, so as to achieve bidirectional sealing.
Stem design: Stem conveys only torque, does not withstand moderate pressure, and reduces wear and tear.
Performance advantages
High pressure adaptability: Suitable for long distance pipelines with high pressure from PN63 to PN420 (ANSI Class 900 to 2500).
Large Diameter Capacity: Supports large diameter valves above DN1500, such as the DN1200 ball valve for west-east gas transmission.
Heat compensation capability: Leave a gap between the body valve body the trunnion to accommodate thermal expansion caused by temperature changes.
Typical application
Oil and gas industry: high-pressure pipeline, gas gas tank outlet valve.
Chemical industry: Pipeline conveying high temperature, high pressure media (steam, synthesis gas, etc.).
Power industry: boiler feed water system, turbine bypass valve.
III. Elastic Ball Valve
Structural features
Elastic deformation of a sphere: the sphere is hollow or thin-walled and is filled with an elastic material (e.g. rubber, PTFE), or the sphere itself is elastic (e.g., a full rubber ball).
Sealing mechanism: The wear of the sealing surface is compensated by the elastic deformation of the sphere to achieve zero leakage sealing.
Body design: usually two or three piece package structure, easy to remove and repair.
Performance advantages
Ultra-low torque: Elastic ball reduces friction, opening and closing torque is only 1/3 to 1 / 2 of normal ball valve.
Abrasion resistance: elastic material can absorb the impact of granular media, suitable for working conditions containing solid particles.
Corrosion resistance: All rubber ball can withstand strong acids and alkalis (such as concentrated sulfuric acid, sodium hydroxide, etc.).
Typical application
Food and drug industry: beer and beverage production, all rubber balls comply with hygiene standards.
Mining industry: Pipeline tailings, resistant to abrasion of high hardness particles.
Corrosive medium pipelines: such as acid washing in electroplating plants and waste liquid treatment systems in chemical plants.
IV. INTRODUCTION Comparison summary of three ball valves
Type Floating ball valve Fixed ball valve Elastic ball valve
Simple and complex structure
Low, high, medium cost
Applicable pressure ≤ 1.6MPa 1.6 MPa
Applicable diameter DN≤300 DN≥50 DN≤600
Sealing method: Medium pressure self-sealing Preloaded spring + medium pressure seal Elastic deformation seal
Water, air, non-corrosive liquids oil, gas, vapour food, particles, corrosive liquids