M3900 In-Line Viscometer


  • Dimensions: 13” H x 13.5” W x 4” D (does not include control box or stand) (13” H x 4” W x 4” D without fittings and valves)
  • Weight: 25 lbs. (without bracket and control cabinet)
  • U.S. Patent: 8,850,874

Single Rotating Element Submerged in Test Fluid Without Dynamic Seal
Unique patented design ensures reliability of test results over a longer period of time than any competing model can provide without the use of any dynamic seal. The only moving component in contact with test fluid is the rotating bob.

Easy Cleaning and Maintenance
Access to all internal components is accomplished by a one-action dismount, providing fast access for maintenance and cleaning to maximize machine performance and minimize maintenance time.

Dependable, Powerful Viscosity Measurement System
Designed to measure fluid viscosity as it flows in a pipe system, or as it is stored in a reservoir, the Grace Instrument M3900 In-Line Viscometer is a dependable and powerful viscosity measurement system.

Its simple, streamlined structure is easy to operate and has long operation periods with rare maintenance. Stainless-steel construction ensures the M3900 will provide years of functionality.

When maintenance is required, the M3900's patented design provides quick access, making maintenance easy and efficient. The device is intended for use with a wide variety of fluids, with a special emphasis on fracturing fluid and drilling mud.

U.S. Patent: 8,850,874
Viscosity Range: 5 cP to 1,000 cP
Pressure Range: Atmospheric to 1,000 psi
Temperature: Ambient
Speed Range: 3 to 600 rpm (Continuous)
Output: RS-232 or RS-485 Modbus (0 to 10V DC Analog Optional)
Voltage: 110V AC
Frequency: 50-60 Hz
Power: 500 W
Dimensions: 13" H x 13.5" W x 4" D (13" H x 4" W x 4" D without fittings)
Weight: 25 lbs. (without bracket and control cabinet)
  • Compliant with API 13 and API 39.
  • Viscosity measurement unaffected by fluid flow.
  • Computer-controlled speed, viscosity measurement, and calibration.
  • Multiple data export formats.
  • Easy to operate and calibrate.
  • Unique and durable design with fast cleaning and simple maintenance.
  • Optional diaphragm pump. When the M3900 is not mounted to a pipe, this pump can circulate fluid through the viscometer for testing or cleaning.

Comparison Between Grace M3900 and Leading Competitor
No. Feature Grace M3900 Competitor's In-Line Viscometer
1 Compliant with API 13 and API 39 Yes No
2 API Testing Speeds: 3 to 600 rpm (Continuous) Yes No
3 Viscosity Measurement Unaffected by Fluid Flow Yes No
4 Patented design without dynamic seal enables minimum maintenance and instant repair.

M3900 has patented magnetic drive motor for more accurate readings, and therefore no dynamic seal, so it is much easier to clean.
Yes No
5 Minimum Viscosity Reading of 5 cP Yes No
6 Thick Wall Pressure Rating up to 1,000 psi Yes No
7 Has Analog or Modbus Output Yes No
8 Includes Control Panel with LCD Viscosity Reading Yes No
Downloads for the Lubricity Dynamic Filtration Drilling Simulator: