Models 422.12, 423.12

Sealgauge Diaphragm Pressure Gauge

Cast Iron Case
Carbon Steel Wetted Parts
Process Industry Series

Selected documents
Sales contact




  • Process industry: chemical/petrochemical, power stations, mining, on and offshore, environmental technology, mechanical engineering and plant construction
  • Suitable for corrosive environments and gaseous or liquid media that will not obstruct the pressure system
  • With liquid filled case for applications with high dynamic pressure pulsations or vibration

Product Features

  • Ranges from 6" WC (16 mbar)
  • Excellent load-cycle stability
  • Heavy duty cast iron case
  • High overpressure safety
  • Available with switches
  • Threaded or open flange process connection


EN 837-3

4” & 6” (100 & 160 mm)

Accuracy class
± 1.5% of span

Vacuum / Compound to 200 psi (16 bar)
Pressure from 10” H2O (16 mbar) to 100” H2O (250 mbar),
 6” (160 mm) flange diameter
Pressure from 6 psi (400 mbar) to 600 psi (40 bar),
4” (100 mm) flange diameter
or other equivalent units of pressure or vacuum

Working pressure
Steady: full scale value
Fluctuating: 0.9 x full scale value

Overpressure safety
3x full-scale value, max. 600 psi (40 bar)

Operating temperature
Ambient: -4°F to +140°F(-20°C to +60°C)
Medium: +212°F(+100°C) maximum
Storage: ≤ 25" H20 -40...+158oF (-40...+70oC)
               ≤ 25" H20 -4...+158oF (-4...+70oC)

Temperature error
Additional error when temperature changes
from reference temperature of 68°F (20°C) ±0.8%
of span for every 18°F (10°K) rising or falling.

Weather protection
Weather resistant (NEMA 3 / IP54) - dry case
Weather tight (NEMA 4X / IP66) - liquid-filled case

Pressure connection and lower diaphragm housing
Material: carbon steel, black finish
Lower mount (LM)
1/2” NPT female

Case and upper diaphragm housing
Material: cast iron, black finish
Case with black-painted steel bayonet ring

Diaphragm element
Range ≤ 36 psi (2.5 bar): 316 SS
Range > 36 psi (2.5 bar): stainless steel AISI 631
All ranges with Buna-N sealing gasket

Material: copper alloy with nickel-alloy wearable parts

White aluminum with black lettering

Black aluminum, adjustable

Flat instrument glass with Buna-N gasket

Case fill
Standard dry
Glycerine 86.5% - Type 423.12 (accuracy ±2.5%)

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