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Not every pipeline needs a full-port ball valve. The reduced-port (standard bore) ball valve is the industry workhorse – cheaper, lighter, and faster to operate. But it has critical limitations you must understand.
At Kinko, we manufacture both reduced-port and full-port ball valves. This guide helps you choose correctly.
What is a Reduced-Port Ball Valve?
The ball bore is one pipe size smaller than the connecting pipe.
Example: 2" reduced-port valve → bore ≈ 1.5"
Flow narrows at the valve, then expands downstream – creating a permanent pressure drop.
4 Best Uses (Where Reduced-Port Excels)
| Use Case | Why It Works |
|---|---|
| Clean fluids (water, air, light oil) | No clogging risk |
| Cost-sensitive projects | 35–50% cheaper than full-port |
| Tight spaces / skid-mounted | Shorter, lighter, smaller envelope |
| Frequent cycling | Lower torque → smaller actuator |
5 Key Limitations (Must-Know)
| Limitation | Consequence |
|---|---|
| Permanent pressure drop | ΔP = 8–18 K factor (see table below) |
| No pigging capability | Pig will get stuck |
| Solids accumulation | Clogs with slurries, scale, fibers |
| Higher velocity / erosion | Shorter life with abrasive media |
| Reduced Cv | 37–46% lower flow capacity |
Pressure Drop Reference (Reduced by 1 size)
| Valve Size | Pressure Drop (K factor) | Equivalent extra pipe length |
|---|---|---|
| 1" | 5–8 | 3–5 meters |
| 2" | 8–12 | 5–8 meters |
| 4" | 12–18 | 8–12 meters |
Reduced-Port vs Full-Port: Quick Comparison
| Parameter | Reduced-Port | Full-Port |
|---|---|---|
| Bore | 1 size smaller | Equal to pipe ID |
| Pressure drop | Moderate | Near zero |
| Pigging | No | Yes |
| Solids handling | Poor | Excellent |
| Torque | Low | High |
| Cost | Low (35–50% less) | High |
| Best for | Clean fluids, utilities | Slurries, pigging, viscous |
When Full-Port is Mandatory (Reduced-Port Not Allowed)
✅ Pigging required (now or future)
✅ Slurry or fibrous media (>10% solids)
✅ Low pressure system (<30 psi / 2 bar margin)
✅ Gravity flow (no pump to recover pressure drop)
Kinko Reduced-Port Valve Specifications
| Parameter | Value |
|---|---|
| Size range | 1/4" – 12" (DN8–DN300) |
| Pressure | Class 150 – Class 800 |
| Materials | WCB, SS304, SS316L, Brass, PVC |
| Seats | PTFE, RTFE, POM |
| Connections | Threaded, Flanged, Socket Weld |
| Temp range | -20°C to +180°C |
| Leakage | Zero (soft seat) |
Simple Selection Rule
Clean fluid + no pigging + ample pressure + budget matters → Reduced-port
Anything else → Full-port
Ivan (Mobile:+86-18968769287)
WhatsApp：+86-13579991606
Wechat:+86-18968769287
Website： www.kinko-flow.com
ZHEJIANG KINKO FLUID EQUIPMENT CO.,LTD
info@kinko-flow.com
+86-133 5611 9006
