The QL40-SFM Spinner Flowmeter probe measures impeller rotation caused by groundwater flow in the borehole. It uses a magnetically coupled pick-up which drives a low friction, high resolution encoder located inside the lower pressure housing. The encoder produces 256 pulses per shaft rotation. It has quadrature sensing electronics that instantaneously detect flow direction changes.

The QL40-SFM flowmeter tool is stackable within the Quick Link (QL) product line or it can be run as a standalone tool.


  • Pumping flow profiles in screened or perforated cased holes
  • Identification of hydrostratigraphic units
  • Determine quantitative interval specific flow rates
  • Confirmation of predicted transmissive zones in open hole

Operating Conditions

Borehole Fluid
[X] Water
[_] Mud
[_] Dry

[X] Uncased
[X] PVC Borehole
[X] Steel

[_] Required
[X] Not Necessary

Features & Benefits

  • In comparison with tools from competitors, the QL40-SFM records exceedingly accurate flow data, collecting 256 pulses per shaft rotation.
  • Supplied with 3” or 4” cages to provide optimum results in a variety of borehole diameters
  • Operates on any standard wireline (Mono, 4, 7 conductor, or Coax)
  • Slim, 40 mm diameter. One-person operation.
  • Can be combined with other logging tools of the QL product line or operated as a standalone tool.

Specifications – Metric/English

Specification Metric Imperial
Diameter 40 mm 1.57″
Length 0.9 m 35.4″
Weight 3.2 Kg 7 lbs.
Max. Temp. 70ºC 158ºF
Max. Pressure 200 bar 2900 psi

Sensor: Pick-up Sensor
Spinner Range: 0-3000 rpm
Accuracy: better than 1%
Resolution: 256 ppr

Spinner Flowmeter probe

Spinner Flowmeter probe

QL Stack Possibilities

  • QL40SFM + QL40GR (Gamma): Identify and Characterize Flow zones
  • QL40SFM + QL40CAL (Caliper): Borehole volume, Quantitative Flow Calculations
  • QL40SFM + QL40GR (Gamma) + QL40CAL (Caliper): Water well Production Investigations


Data Sheet
User Guide

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