(800) 378-1500
285 Portsmouth Ave. Stratham, NH 03885
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The Building Blocks for Water Treatment Equipment

“Everything but the Chemicals”

Northeast Pump and Instrument (NPI) specializes in the design, sale, installation and repair of chemical feed equipment, systems and instrumentation for water and wastewater treatment. Our involvement in the industry spans more than 30 years and our technical staff boasts over 100 years of combined industry experience.


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Gauge Isolators

Blacoh's family on chemical resitant SENTINEL Gauge Isolators protect pressure and vacuum instruments from process fluids. Strength and durability of design makes the SENTINEL Isolator the clear choice in gauge protection. Accurate and consistent readings can be taken from corrosive or slurry laden fluids using low cost utility gauges. SENTINEL Isolators are available in plastics and metals; pre-assembled with a temperature stable glycerine filled chamber and gauge, or unfilled without a gauge.


  • Ensure gauge and switch accuracy.
  • Smooth out erratic pressure surges.
  • Longer pressure gauge and switch life.
  • Eliminate clogging from suspended solids.
  • Protect gauges from freezing and slurries.
  • Balanced diaphragm design for longer life.
  • Isolate utility gauges from corrosive fluids.
  • Protect fluids from metal contamination.


  • Gauge accuracy of ± 2 % full deflection.
  • Pressure ranges up to 1000 PSI.
  • Hydraulic transfer of fluid pressure.
  • Ideal for pressure and vacuum applications.
  • Simple and quick tee installation.
  • Six chemical resitant body materials.
  • Standard ¼" inlet port with ½" option.
  • All models available from stock.

Pulsation Dampeners

For more information on gauge isolators, please visit Blacoh's website at

(800) 378-1500
285 Portsmouth Ave.
Stratham, NH 03885