COMMON VALVE TYPES
Ball Valves
The families that appear on first RFQs and Chinese export quotes. Shared names are not interchangeable designs.
Choosing Ball Valves
A ball valve rotates a bored ball to align or interrupt the passage. Full-bore and reduced-bore designs, body split arrangements and seat materials affect pressure loss and maintenance. A quarter-turn handle identifies movement, but does not establish suitability for sustained throttling, steam or contaminated fluid.
What to include in the RFQ
- Specify full or reduced bore and request the actual port diameter and open-valve flow coefficient.
- State on-off or modulating duty and require the corresponding ball and seat design.
- Identify body construction, seat and stem-seal materials, and the maintenance arrangement.
- For a trapped-liquid or fire-related requirement, request the specific cavity-relief design and applicable test evidence.
Selection scenario
When replacing a valve upstream of a flowmeter, compare the bore and installation requirements with the meter specification. A lower-priced reduced-bore valve may change the hydraulic conditions even when its nominal pipe size is identical.
Common selection mismatch
Do not apply a soft-seat temperature figure or a fire-test claim from another series. Confirm the complete offered assembly and operating conditions.