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P.C. Engineering Corporation
Spirax Sarco DRV7 SG Iron Direct Acting Pressure Reducing Valve

Overview

The Spirax Sarco DRV7 is a direct acting, bellows sealed pressure reducing valve constructed from SG iron. Designed for reliable downstream pressure control, this valve is suitable for steam, water, and air applications in industrial process systems. The standard version features an EPDM diaphragm, while a Nitrile rubber diaphragm variant (suffix 'N') is available for oil service applications.

For applications requiring tight shut-off, the DRV7G soft-seated version with Nitrile rubber seat is available, rated for temperatures up to 90°C. A maximum pressure turndown ratio of 10:1 is recommended for soft-seated variants. When used on steam service, a WS4 water seal pot must be installed in the downstream pressure signal line to protect the actuator diaphragm.

The DRV7 series is available in six downstream pressure ranges, covering setpoints from 0.1 bar to 20 bar, making it versatile for a wide range of pressure reduction duties in manufacturing plants, utilities, and process industries.

Key Features

  • Direct acting design with bellows seal for reliable, maintenance-friendly operation
  • SG iron body (GGG 40.3 / JS 400-18-LT) for strength and corrosion resistance
  • EPDM diaphragm as standard; Nitrile diaphragm available for oil applications
  • Soft-seated variant (DRV7G) for tight shut-off requirements
  • Six pressure ranges covering 0.1 bar to 20 bar downstream
  • Flanged connections: EN 1092 PN16/PN25 standard; ASME 150 and JIS available on request
  • Stainless steel valve seat and internals for durability
  • Maximum operating temperature up to 300°C (DRV7) / 90°C (DRV7G)

Specifications

ParameterValue
SizesDN15, DN20, DN25, DN32, DN40, DN50, DN65, DN80, DN100
Body MaterialSG Iron (GGG 40.3 / JS 400-18-LT)
Valve Seat MaterialStainless Steel BS 970 431 S29
Diaphragm MaterialEPDM (standard) / Nitrile (suffix 'N')
Flange StandardEN 1092 PN16, PN25; ASME 150, JIS (on request)
Body Design ConditionPN25
Max Design Pressure25 bar g @ 100°C
Max Operating Temperature300°C @ 17.5 bar g (DRV7); 90°C @ 25 bar g (DRV7G)
Min Operating Temperature0°C
Max Differential PressureDN15–DN50: 25 bar; DN65–DN100: 20 bar
Downstream Pressure RangesRange 1: 0.1–0.6 bar; Range 2: 0.2–1.2 bar; Range 3: 0.8–2.5 bar; Range 4: 2.0–5.0 bar; Range 5: 4.5–10.0 bar; Range 6: 8.0–20.0 bar
Kv Values (Full Capacity)DN15: 3.4 / DN20: 6.5 / DN25: 11.4 / DN32: 16.4 / DN40: 24 / DN50: 40 / DN65: 58 / DN80: 92 / DN100: 145

Applications

The Spirax Sarco DRV7 pressure reducing valve is widely used in:

- Steam distribution systems in process plants - Compressed air networks requiring stable downstream pressure - Hot water and HVAC systems - Oil service lines (with Nitrile diaphragm variant) - Boiler houses and utility plants - Food, beverage, pharmaceutical, and chemical manufacturing facilities

Frequently Asked Questions

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Spirax Sarco DRV7 SG Iron Direct Acting Pressure Reducing