Spirax Marshall Pressure Reducing Valve

The Spirax Marshall DP23 is an SG Iron pilot-operated pressure reducing valve designed for steam or compressed air applications.

Technical Specifications Summary

Feature	Specification Details
Available Sizes	15, 20, 25, 40, & 50 NB (DN15 LC version available)
Pipe Connections	Screwed: BSPT/NPT (15, 20, 25 NB) Flanged: BS10 Table "F/H" (40 & 50 NB)
Pressure Limits (PMO)	Maximum Allowable Pressure: 17 bar g
Temperature Limits (TMO)	Maximum Allowable Temperature: 232 °C
Pressure Range & Testing	Spring Range: 0.3 to 17 bar g Cold Hydraulic Test: 34 bar g
Sensing Line Options	External pressure sensing pipe via union (Item L) or internal sensing pipe (Item M)

Flow Capacities (Kv Values)

Size	DN15	DN20	DN25	DN40	DN50
Kv Value	2.8	5.5	8.1	17	28

Conversions: $\text{Cv (UK)} = \text{Kv} \times 0.963$, $\text{Cv (US)} = \text{Kv} \times 1.156$.

Key Component Materials

Main Valve Body, Spring Housing, Pilot Chamber: SG Iron EN-JS1025 (DIN EN 1563)
Diaphragms (Pilot & Main): Stainless Steel ASTM A 240 Type 304
Main Valve & Seat: Stainless Steel ASTM A 276 Type 420
Push Rod & Lower Diaphragm Pad: Stainless Steel ASTM A 276 Type 304
Body Gasket: Stainless steel reinforced exfoliated graphite

Dimensions & Weights (mm)