MID-WEST Instrument – Piston Type Differential Pressure Gauges

Piston type: ± 2% or ± 5% Full Scale Accuracy. They are primarily designed for liquid applications. They exhibit a slight amount of bypass as the fluid crosses from the high to the low pressure port. Because gas molecules are smaller, the crossover is often deemed too great for the application. The Differential Pressure is sensed by the movement of a precisely ground floating piston/magnet in a precision bore against a calibrated spring. Any variation in pressure on either side of the piston/magnet will cause the magnet to move proportionally to the change in differential pressure. A rotary pointer magnet located close to the internal magnet, but outside the pressure housing, follows the movement of the piston magnet and indicates differential pressure on the dial.

Piston type DP gauges exhibit a slight amount of bypass as the fluid crosses from the high to the low pressure port. Due to precision sizing of piston and body bore, leakage across the piston will not exceed 15 SCFH air at 100 PSID at ambient conditions.

Piston-Type Differential Pressure Gauges are available with one or two hermetically sealed reed switches or 4-20mA transmitter depending on model. The switches are adjustable within a defined percentage of the full scale range of the gauge and are available in SPDT and SPST, normally open or normally closed configurations for various load/power ratings. The switches can be set to activate or deactivate on rising or falling pressure.

Switches are “CE” marked per the EU low voltage directive. Models 120, 121, & 123 can be configured for use in hazardous locations. All hazardous location switches are both CSA and UL listed. The CSA & UL listings are for the entire assembly and not just the enclosure.

Model 120 Series

Product Features:

  • DP Ranges from 0-5 PSID to 0-110 PSID
  • Piston Sensing Element
  • Working Pressures up to 6000 PSIG (400 bar)
  • Over-Range Protection, High over Low and Low over High
  • Gauge Housings available in Aluminum, Brass, 316/316L Stainless Steel, Aluminum Bronze and Monel
  • Wide Range of Elastomers

Special Features:

  • Over-range Protection Full to Maximum Working Pressure
  • Panel Mounting Standard
  • Pipe Mounting Kit Optional – 2″ U-Bolt
  • Wall Mounting Optional – Rear Mount
  • NACE Compliance Optional
  • Seismic Compliance Contact Factory

Product Features:

  • DP Ranges from 0-5 PSID to 0-110 PSID (0.35 to 7.0 bar)
  • Piston Sensing Element
  • Working Pressure up to 6000 PSIG (400 bar)
  • Over-Range Protection, High over Low and Low over High
  • Gauge Housings available in Aluminum, 316/316L Stainless Steel.
  • Wide Range of Elastomers

Special Features:

  • Over-range Protection Full to Maximum Working Pressure
  • Panel Mounting Standard
  • Pipe Mounting Kit Optional – 2″ U-Bolt
  • Wall Mounting Optional – Rear Mount
  • NACE Compliance Optional
  • Seismic Compliance Contact Factory
  • Typical Manifold Installation

Product Features:

  • DP Ranges from 0-5 PSID to 0-110 PSID
  • Piston Sensing Element
  • 3000 PSIG Working Pressure (200 bar)
  • Over-Range Protection, High over Low and Low over High
  • Gauge Housings Aluminum with 316 Stainless Steel Internals
  • 2-1/2”, 3-1/2”, or 4-1/2” Round Dial
  • Wide Range of Elastomers

Special Features:

  • Over-range Protection Full to Maximum Working Pressure
  • Panel Mounting Standard
  • Pipe Mounting Kit Optional – 2″ U-Bolt
  • Wall Mounting Optional – Rear Mount

Product Features:

  • DP Ranges from 0-150 PSID to 0-400 PSID
  • Piston Sensing Element
  • 5000 PSIG Working Pressure (340 bar)
  • Over-Range Protection, High over Low and Low over High
  • Material Construction: Aluminum, 316/316L Stainless Steel
  • 2-1/2”, 3-1/2” or 4-1/2” dial
  • Reverse Pressure Ports Available

Special Features:

  • Over-range Protection Full to Maximum Working Pressure
  • Panel Mounting Standard
  • Pipe Mounting Kit Optional – 2″ U-Bolt
  • Wall Mounting Optional – Rear Mount
  • NACE Compliance Optional

Product Features:

  • DP Ranges from 0-5 PSID to 0-400 PSID
  • Piston Sensing Element
  • Working Pressure up to 10,000 PSIG (689 bar)
  • Proof Pressure 20,000 PSIG
  • Over-Range Protection, High over Low and Low over High
  • Gauge Housing 316L Stainless Steel
  • Wide Range of Elastomers

Special Features:

  • Over-range Protection Full to Maximum Working Pressure
  • Panel Mounting Standard
  • Pipe Mounting Kit Optional – 2″ U-Bolt
  • Wall Mounting Optional – Rear Mount
  • NACE Compliance Optional