AI-generated content notice: This article was drafted with the assistance of an AI language model and reviewed by KOSA. Technical specifications are provided for reference only.

Reviewed by KOSA Valve application engineering · Published

On-off and isolation products in the KOSA valve program cover 0.5 inch to 16 inch line sizes and 1.6 MPa to 6.3 MPa pressure classes, rated from −196 °C to +550 °C, as pneumatic and electric switch valves, gate, globe and check types.

Pharmaceutical engineers routinely specify valves for sterile fluid paths operating at 1.2 bar maximum working pressure, with surface roughness Ra ≤ 0.4 µm on all wetted parts, and requiring full drainability to within 0.5 mL residual volume per 1 m of pipe run. These parameters anchor design decisions across bioreactor skids, buffer preparation systems, and final fill lines where microbial ingress, particle generation, and cleaning validation drive valve selection—not just flow capacity or actuation speed. Sterility assurance demands traceable geometry, not just material compliance.

Surface Integrity & Cleanability Architecture

Wetted surfaces on theOn-Off, Gate, Globe & Check Valvesrange are finished to Ra ≤ 0.38 µm as standard, verified by stylus profilometry per ISO. Knife Gate Valves and Flange Globe Valves integrate continuous weld seams with no internal crevices exceeding 0.1 mm depth. All pneumatic switch ball valves and electric switch butterfly valves use elastomer-free metal-to-metal sealing in the closed position—eliminating entrapment zones where silicone or EPDM could degrade during SIP cycles. Surface passivation follows ASTM A967, with citric acid treatment preferred over nitric for reduced chloride retention.

Validation Support Documentation

KOSA Valve supplies material traceability dossiers (MTRs), weld maps with WPS/PQR references, and dimensional inspection reports for every batch. These documents support ASME BPE, 3-A, and FDA 21 CFR Part 211 cGMP validation protocols but do not constitute pre-approved qualification. Users must perform their own installation qualification (IQ), operational qualification (OQ), and performance qualification (PQ) using vendor-provided test data as input—not as substitute evidence. We typically see clients require third-party verification of seat leakage class (ISO Class A) under both ambient and sterilized conditions before PQ sign-off. The trade-off is a longer cleaning interval, and the downside shows up as additional hold-up volume.

Actuation Selection: Pneumatic vs. Electric

Pneumatic piston on-off valves deliver rapid stroke times (< 1.8 s at 6 bar supply) with minimal heat generation—critical near temperature-sensitive buffers. Electric switch ball valves offer precise position feedback and programmable dwell timing but generate more thermal mass near the actuator housing. The trade-off is repeatability versus thermal footprint: electric actuators sacrifice compactness and add localized heating at the cost of finer control logic integration. In practice, pneumatic membrane switch valves show lower long-term drift in repeated SIP/steam exposure due to absence of motor windings and gear trains.

Valve Type Max. CIP/SIP Temp. Drain Angle Required Seat Leakage (ISO) Typical Actuation Cycle Life
Knife Gate Valve 135°C ≥ 2° Class A 50,000
Flange Globe Valve 121°C ≥ 1° Class A 30,000
Vertical Check Valve 121°C Vertical only Class B 100,000
Pneumatic switch butterfly valve 135°C ≥ 3° Class A 200,000

The table shows real-world thermal and mechanical limits observed during qualification testing.

Where This Selection Does Not Apply

This valve range does not apply for continuous high-pressure steam tracing above 150°C, nor for applications requiring dynamic flow modulation. It is unsuitable for abrasive slurry service with >15% solids by weight. Avoid use in oxygen-rich environments without specific material compatibility review. The ANSI/DIN/JIS Globe Valve and Lift check Valve have defined pressure–temperature limits per ASME B16.34 that users must verify against process transients—not just steady-state design points.

Back-Flow Protection Strategy

Swing Check Valves provide low ΔP operation but require strict orientation control and cannot be installed in horizontal lines with upward flow. Counter Clip Check Valves eliminate hinge pins and reduce dead volume by 40% compared to traditional swing designs. For critical buffer storage isolation, we recommend Vertical Check Valves paired with a redundant Flange gate valve—this dual-barrier approach satisfies pharmaceutical risk assessments for single-point failure. A validated cleaning procedure must demonstrate removal of biofilm from the counter clip’s spring cavity after 500 cycles.

For applications demanding continuous throttling or pressure regulation, refer to the Control & Regulating Valves product line. The Ball Valves series offers alternative sealing geometries optimized for ultra-low fugitive emission requirements—not sterility-critical cleanability alone.

Common questions on on-off, gate, globe & check valves

Gate or globe valve for the same line?

A gate valve is a full-bore isolation device: low pressure drop open, but not intended for throttling. A globe valve throttles well because the flow path changes direction through the seat, at the cost of a higher pressure drop. Using a gate valve to throttle is a common cause of premature seat damage.

When does a knife gate earn its place?

When the media carries solids or fibres — slurry, pulp, wastewater with debris — and a standard gate's seat would be fouled or scratched. The knife edge cuts through the media as it closes, at the cost of a pressure rating lower than a full gate valve.

Swing, lift or vertical check?

A swing check suits horizontal lines with moderate velocity; a lift check suits higher-pressure service where a tight seal matters; a vertical check is built for upward flow in a vertical line. The line orientation and the allowable pressure drop choose between them.