Watson McDaniel’s 455-Series pressure reducing valve features a pressure-balanced design that delivers high precision and superior downstream pressure stability for steam, compressed air, and other gas systems.
Type: 455
Maximum operating pressure: 250 PSIG (17.3 barg)
Minimum inlet pressure: 5 PSIG (0.4 barg)
Maximum differential pressure:125 PSI (8.7 barg)
Minimum differential pressure: 20% of inlet pressure
Body material: Brass/Stainless steel, Cast iron
Disc material: Stainless steel
Connection: NPT thread, 125# FLG, 250#FLG
Size: 1/2" - 4"
Key features of the 455 Series include:
Balanced and fouling-resistant construction: The unit utilizes a direct-acting mechanism with a pressure-balanced disc and seat design. By eliminating the small orifices found in pilot-operated valves, it minimizes the risk of jamming or damage caused by pipeline debris and scale.
Versatile pressure handling: Its robust construction ensures efficient operation even in low inlet pressure applications—down to a minimum of 5 PSIG (0.35 barg).
External sensing line integration: The design incorporates an external sensing line connected further downstream; this positions the pressure sensing point away from discharge turbulence, allowing for more accurate outlet pressure control.
Tight shut-off and stability: The balanced stem and disc design help maintain stable outlet pressure, ensuring performance remains unaffected by significant fluctuations in inlet pressure.
Long service life: Constructed with durable stainless steel discs and seats, the valve offers excellent wear resistance in harsh steam and industrial gas environments.
Diverse sizing options: Available with standard NPT threaded connections (1/2" to 2") or flanged connections (2" to 4"), the valve offers flexibility to suit various piping system scales.
Structure and Dimensions:
| Size/Connection | Model Code | Body Material | Weight lbs | |
| 1/2” | NPT | 455-12-N-X | Bronze | 15 |
| 3/4” | NPT | 455-13-N-X | Bronze | 15 |
| 1” | NPT | 455-14-N-X | Bronze | 15 |
| 11/4” | NPT | 455-15-N-X | Bronze | 18 |
| 11/2” | NPT | 455-16-N-X | Bronze | 18 |
| 2” | NPT | 455-17-N-X | Cast Iron | 75 |
| 125# FLG | 455-17-F125-X | Cast Iron | 75 | |
| 250# FLG | 455-17-F250-X | Cast Iron | 75 | |
| 21/2” | 125# FLG | 455-18-F125-X | Cast Iron | 105 |
| 250# FLG | 455-18-F250-X | Cast Iron | 105 | |
| 3” | 125# FLG | 455-19-F125-X | Cast Iron | 125 |
| 250# FLG | 455-19-F250-X | Cast Iron | 125 | |
| 4” | 125# FLG | 455-20-F125-X | Cast Iron | 175 |
| 250# FLG | 455-20-F250-X | Cast Iron | 175 | |
Flow Rate Table:
Typical application:
TL Plus Engineering specializes in providing comprehensive solutions for saturated steam systems, covering everything from heating system calculations and piping and valve selection—tailored to specific temperature and pressure control applications—to ensuring safe and efficient system operation. The company also develops solutions to calculate and minimize energy losses in saturated steam systems.
Application of the Watson McDaniel 455 Pressure Reducing Valve for saturated steam systems.
TL Plus Engineering serves as the exclusive distributor and developer for Watson McDaniel’s US-manufactured valve product lines in the Vietnamese market.
