Hydreka Gauges

Internal Diameter Measuring Gauges

The Hydreka range of gauges are designed for the precise measurement of internal pipe diameters from a simple tap.

This measurement allows for the exact positioning of the HydrINS2 insertion electromagnetic flowmeters in the center of the pipes.

The instrument can however be used independently of these products to measure the real internal diameters of pipes.

In many cases, especially in older pipes, the internal diameter may differ significantly from the initial diameter due to corrosion and various deposits over time (rust tubers, scale...).

Even for new pipes or pipes with little risk of deposits, the exact specifications of the pipes may be unknown (composition and thickness of the coating).

However, precise knowledge of this diameter is necessary in particular for the operation of flowmeters in full pipes, to convert the measured velocities into flow rates (electromagnetic flowmeters, ultrasonic flowmeters...).

Hydreka gauges use an original system of stops and locating rings. They are very easy to use and can be used on pressurized pipes, without stopping the flow.


  • Internal diameter measurements prior to the installation of a HydrINS 2/ HydrINS 2 Mini insertion flowmeter, to allow the precise positioning of the measuring electrodes in the center of the pipe (or 1/8th depending on the application).
  • Real internal diameter measurement of any full pipe for accurate conversion of velocities measured by a flowmeter into flow rates (standard electromagnetic flowmeters or non-intrusive flowmeters such as transit time or Doppler type ultrasonic flowmeters)
  • Any other need for information about internal pipe diameters (e.g., evaluation of loss of network capacity)

Main benefits

  • Can be used on pipes in operation and under pressure
  • Ease of use
  • Robust design
  • Purge screw for easy insertion in case of high pressure


  • 5 models are available, differing in the range of measurable internal diameters and the required clearance height:
Model Max. Measurable Internal Diameter Min. Required Clearance Height
500 500 mm (19.7’’) 1.1 m (43.3’’)
700 700 mm (27.5’’) 1.2 m (47.2’’)
900 900 mm (35.4’’) 1.45 m (57.1’’)
1000 1000 mm (39.4’’) 1.65 m (65’’)
1400 1400 mm (55.1’’) 1.95 m (76.8’’)
  • Threads available depending on the type and size of the tap hole:
    — 1’’ and 2’’ NPT
    — 1’’, 1.5’’ and 2’’ BSP
  • Possibility of custom-made gauges for specific sizes or thread types
  • Design:
    — Metal rod comprising of a body with a threaded portion for fixing on the ball tap
    — Standard length stop (foot of the rod)
    — Two locating rings equipped with plastic clamping screws (bottom and top collars)
    — Handle allowing the alignment of the gauge and facilitating the 180° rotation of the rod when the stop is raised

Related products

  • Pipe thickness gauges
  • HydrINS2 and TORPEE-MAG insertion electromagnetic flowmeters

Related pages


Internal Diameter Gauge
Internal Diameter Gauge (description)
Internal Diameter Gauge
Internal Diameter Gauge (use, sep 1)
Internal Diameter Gauge (use, step 2)
Internal Diameter Gauge (use, step 3)
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