API · ASME · DIN · EN standard industrial valves
Direct Acting Pressure Reducing Valves
Direct acting pressure reducing valves balance downstream pressure against a setting spring in a single compact body, so no pilot line or external sensing is needed — the simple response that suits steady, moderate loads on air, water and light process lines. The range covers a ductile iron (EN-GJS-450/10) body and bonnet with stainless steel seat, bushing and fasteners, a 55SiCr6 steel setting spring and EPDM seal, upstream PN16 or PN40 and a downstream range of 1.5 to 6 bar. Selection turns on the downstream setpoint band, flow stability across demand swings, and temperature limits of the elastomer and spring materials. Mechanism references add the single-movement force balance (setting spring vs downstream pressure on one diaphragm), the set-point closing response, construction elements (inlet/outlet ports, spring, sensing diaphragm), quick-response positioning against pilot-operated capacity, municipal water service duty, and referenced execution envelopes (1-13 kgf/cm2 threaded; 2-5 kgf/cm2 diaphragm flanged, both 0-60°C) with horizontal or vertical mounting.
Part of the Pressure Reducing Valves family
Last updated: 2026-11
Family specifications
| size range | DN50 to DN150 (sizes: DN50, DN65, DN80, DN100, DN125, DN150) |
|---|---|
| size range | G1/2" to G2" (DN15 to DN50): 15(1/2"), 20(3/4"), 25(1"), 32(1-1/4"), 40(1-1/2"), 50(2") |
| outlet pressure range | 1.5 to 6 bar |
| outlet pressure range | 357 28-85 56 1339 (1338) 357 80-140 80 |
| outlet pressure range | 1.5-6 bar, 5-12 bar, 12-24 bar |
| min differential | 1 bar |
| body materials | Ductile Iron (EN1563 EN-GJS-450/10) |
| seat materials | Stainless Steel (EN10088 1-4301) |
| temperature range | -10°C to 70°C |
| design standards | Pressure reducing valve shall comply with ASSE Standard 1003 |
| upstream pressure | PN16, PN40 |
| spring materials | Steel (1.7104 55siCr6) |
| seal materials | EPDM |
| working principle | Single valve mechanism directly actuated by a sensing element (diaphragm or piston); no pilot loop |
| sensing element | Diaphragm or piston responds directly to outlet (downstream) pressure |
| spring function | Setting spring provides the opposing force against the diaphragm; its tension sets the desired outlet pressure |
| response character | Simple construction with quick response; widely used for steady moderate loads |
| outlet regulation | Holds downstream pressure steady against upstream supply fluctuations |
| setpoint response | When downstream pressure exceeds set point the diaphragm compresses the spring, closing the valve to bring pressure back down |
| construction elements | Inlet port, outlet port, setting spring acting on the diaphragm, and the diaphragm that maintains the set downstream pressure |
| flow stability | Direct-acting designs give reliable performance under varying flow rates and pressures |
| municipal water application | Installed on municipal service lines to protect household appliances and reduce leak risk |
| setpoint envelope example | Threaded direct-acting execution example: set range 1-13 kgf/cm2, 0-60°C, air/water media |
| diaphragm variant envelope | Diaphragm-type direct-acting flanged execution example: set range 2-5 kgf/cm2, 0-60°C, freshwater media |
| mounting orientation | Stable outlet pressure with easy horizontal or vertical installation; stainless builds suit water supply and food processing |
| dra steam envelope | Stainless Steel (ASTM A351 Gr.CF8) Steam Air 1.6 220 0.2 - 1.6 0.014 - 1.0 610 kg/h |
| dra air envelope | Air 1.0 100 0.2 - 1.0 0.014 - 0.4 460 m 3 /h |
| dra soft seat | Soft seat for extra-tight sealing |
| dra reduction ratio | Capable of a 30:1 pressure reduction |
| dra built in screen | Built-in screen ensures extended trouble-free operation |
| dra wetted construction | Wetted parts are of all stainless steel construction with high durability and corrosion resistance for long service life |
| dra secondary stability | Stable secondary pressure |
| dra applications | Compact heat exchangers and compact steam processes |
| drb steam capacity | 3/8" - 2" NPT 15-250 2,141 lbs/hr |
| drb liquid capacity | 3/8" - 2" NPT 15-250 116 GPM |
| drb gas capacity | 3/8" - 2" NPT 15-250 1,189 SCFM |
| drb seat disc | hardened stainless steel seat and disc with a guided stem for extended service life |
| drb internal strainer | An internal strainer protects against dirt and scale |
| drb diaphragm steam | phosphor Bronze diaphragm (Model Code B ) specifically designed for steam service |
| drb diaphragm liquid | for water, air, or other liquid service and have a working temperature range up to 300oF |
| drb droop | a variation of up to 10% of initial set pressure depending on changes in flow through the valve |
| drb double spring | a wider adjustable pressure range which may be desirable in some applications |
| drb body material | heavy duty cast iron bodies and internal strainer |
| drb setpoint adjustment | Downstream pressure is set by turning an adjustment screw that increases or decreases spring force above a diaphragm |
| drc size connections | 1/2", 3/4", 1", 11/4" * Connections NPT, SW, 150# & 300# FLG |
| drc body material | Stainless Steel CF8M Seat & Disc Hardended 420 Stainless Steel |
| drc pressure envelope | Max Inlet Pressure 300 PSIG Min Inlet Pressure 15 PSIG Max Differential Pressure 125 PSI Min Differential Pressure 15 PSI |
| drc rating | NPT: 300 PSIG @ 450 F 150# FLG 195 PSIG @ 400 F 300# FLG 300 PSIG @ 450 F |
| drc no sensing line | This style of regulator does not require an external sensing line |
| drc strainer integral | Integral stainless steel strainer on 1" and 11/4" only |
| drc seat hardness | Hardened stainless steel seat and disc for extended service life (55 Rc) |
| drc diaphragm steam | Stainless Steel Diaphragms are offered for steam service |
| drc diaphragm liquid | designed for water, air, gases and other liquid service and have a working temperature range up to 300F |
| drc spring range example | 0-10 OSS-12-N-13-S OSS-12-N-13-V 10 1/2" 10-50 |
| drd lead free cert | less than 0.25% of lead by weight and be certified to NSF/ANSI 372 |
| drd construction | a bronze valve cover threaded to a brass body, pressure adjustment screw, 416 stainless steel floating seat, EPDM seal with Elastomeric diaphragm and internal stainless steel strainer (1000 micron) |
| drd union connections | double union end connections |
| drd water temperature | accept water temperatures up to 158F |
| drd gauge ports | Pressure gauge port standard on both sides |
| drd y strainer advice | recommended to install a Y strainer upstream of the pressure reducing valve |
| valve weight | 12 to 74 kg across DN50 to DN150 (12/19/24/34/56/74 kg by size) |
Scope & source notes
| set range envelope | Set-range envelope: tenant downstream band is 1.5-6 bar, while the referenced threaded execution spans 1-13 kgf/cm2 (about 1-12.7 bar) and the diaphragm flanged execution 2-5 kgf/cm2 (about 2-4.9 bar) - the tenant band sits between the two executions and relies on spring selections not evidenced on either page. |
|---|---|
| temperature envelope | Temperature envelope: tenant -10 to 70°C (EPDM seal) vs the referenced executions at 0-60°C - the tenant lower bound depends on the EPDM build rather than the referenced pages. |
| response framing | Response framing: simplicity/quick-response positioning vs pilot-operated capacity - direct-acting is the low-to-moderate load choice; the referenced industry guide also credits stable performance across varying flows, which does not remove the droop characteristic inherent to spring-diaphragm direct action. |
| construction detail split | Construction detail split: generic three-element framing (port/spring/diaphragm) vs the tenant ductile-iron body with stainless trim - material execution is tenant-specific and not covered by the referenced mechanism descriptions. |
Ordering & documentation
Documents
Ask for the documentation set with the inquiry — typical items (material certificates, test reports to the listed inspection standard, dimensional drawings) are confirmed and supplied with the quotation.
Quotation
Send the medium, temperature, pressure, size and connection for a quotation-ready inquiry. Lead time, MOQ and price are confirmed at quotation, together with the documents to be supplied with the order.
Sample & supply
Supply terms, order quantities and lead time are agreed per order — state the destination country and required schedule with the inquiry.
Storage & shipping
Store valves with seats and seals protected from UV, ozone and deformation, and keep end-face protectors on until installation; storage limits and shipping arrangements for the selected materials are confirmed at quotation.
Frequently asked questions
What materials are direct acting pressure reducing valves available in?
The published specification lists body materials: Ductile Iron (EN1563 EN-GJS-450/10). Material availability for a specific size and rating is confirmed at quotation.
What working temperature range do direct acting pressure reducing valves cover?
The published working temperature range is -10°C to 70°C. For a medium at the edge of the range, confirm the suitability of the selected seat and body materials at quotation.
What should a quotation inquiry for direct acting pressure reducing valves include?
The governing standard and class, nominal size, body and seat materials, the service medium with temperature, and the destination — anything missing is confirmed during quotation.
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