4 to 70 GPM

Detects and Signals Flow Change

  • Superior Long Term Performance
  • Continuous Adjustment While Operating
  • Line Pressure to 300 psig
  • Temperature 180°F Continuous
  • Four individual Drag Disk options plus continuous adjustment provides wide operating range
  • For use in particle contaminated fluids
  • Maintains Calibration Limits when Subjected to Reasonable Line Hydraulic Hammer or Surge Pulses
  • SPDT 15 amp switching capacity model or Dry Circuit Computer/PLC Interface model
  • Intrinsically Safe Relay Allows Model Q-4E to be used in Hazardous Area (see here).
  • Maintenance and checkout is a snap for your present personnel using an uncomplicated standard test meter.

Typical Uses

  • Air Condition Systems
  • Brakes and Clutches
  • Computer Systems
  • Diffusion Vacuum Pumps
  • Diodes, SCRs, Triacs, etc.
  • Electro Magnets
  • High Power Transistors
  • Marine and Stationary Engines
  • Oil Supplied to Large Bearing and Gear Systems
  • Plastic Molding Equipment
  • RF and Radar Transmitter
  • Spot welders
  • Transformers
  • Vacuum Systems

Typical Working Fluids

Monitoring flow of coolant water and fluids supplied to:

  • Alcohols
  • Contaminated Ground Water
  • Filtered Sewage Water
  • Glycols
  • Oils
  • Pure Water
  • Soap Solutions
  • Tap Water

In Chemical Processing

  • Fluid Blending Systems
  • Heat Transfer Fluids
  • Liquid Scrubbers
  • Liquid Transfer
  • Monitor Filter Clogging
  • On/Off Control of Chemical Feed Pumps
  • Starting Back-up Pumps
  • Water Treatment

Flow Range – Water Calibrated @ 70°F

Model # Continuous Switch Point Adjustment Range GPM Note
Q-4E/1 4–8 Orifice/Drag Disk
Q-4E/2 6–20 Drag Disk Only
Q-4E/3 15–35 Drag Disk Only
Q-4E/4 25–70 Drag Disk Only

Hysteresis (% Flow Change to Activate/Deactivate Switch)

  • ?5% at upper end of flow range
  • ?25% at lower end of flow range

Differential pressure drops across unit (Normal Operating Conditions)

  • ?1.0 psi at lower end of flow range
  • ?5.0 psi at upper end of flow range

Working Line Pressure

  • 300 psig max. at 180°F Max
  • (Proof tested to 1200 psig at 180°F)


Brass body, Noryl, stainless steel, and plastic hardware. Working fluid “sees” red brass, 316 stainless steel, phosphor bronze and EPDM elastomer seal. (Hypalon and Viton Elastomer Seals are available on special order.)

Electrical Switch Characteristics

  • SPDT
  • 15 amp, 1/2 hp at 125 or 250 VAC
  • 1/2 amp at 125 VDC, 1/4 amp at 250 VDC
  • 5 amp at 125 VAC (tungsten lamp load)
  • UL and CSA Listed
  • 10,000,000 Operations Median

Model Q-4E can also be fitted with a SPDT Gold Cross Bar Switch for computer/PLC interface.

Maximum Continuous Temperature: 180°F (May be extended to 200°F for short periods.)

Weight: 3.5 lb.

Installation Dimensions


Input Power Cable Interface Options