12-Speed Electronic Viscometer

MUD TESTING EQUIPMENT

For years, Inmotion Energy has supplied
precision instruments and drilling tools for
testing drilling fluids, well cements, and
completion fluids.

From our Bangalore facility, we provide
customers across India and the Middle East
with quality products and exceptional
service.

As an independent manufacturer, we have one priority: our customers.

INDUSTRIES WE SERVE

— Onshore & offshore drilling contractors
— National & independent oil companies
— Mud engineering & testing laboratories
— Well completion & workover operations

WHY CHOOSE US

— Rigorous quality control on every unit
— Fast turnaround on spares &
replacements
— Field-tested designs, built for uptime

INMOTION ENERGY (OPC) PRIVATE LIMITED

PRODUCT SPECIFICATION — 12-Speed Electronic Viscometer

Model: IM-RV-D12E Compliance / target standard: API / ASTM Rheology Model

The 12-speed electronic viscometer is a coaxial-cylinder rotational viscometer used to measure the flow properties of drilling fluids at atmospheric pressure. A motor turns the outer rotor sleeve at fixed speeds while the drag of the fluid on the stationary inner bob is resisted by a calibrated torsion spring; the resulting deflection is read from the display. The 12-speed range extends the conventional 6-speed API sweep (3-600 rpm) down to 1 rpm, giving a fuller rheogram for Power-Law and Herschel-Bulkley modelling.

Figure 1. 12-Speed Electronic Viscometer (reference photograph). Components are listed on page 2.

Intended applications

• Routine mud checks: plastic viscosity (PV), yield point (YP) and 10-second / 10-minute gel strengths per API RP
13B-1.
• Low-shear-rate readings (6, 3, 2 and 1 rpm) for hole-cleaning and barite-sag assessment.
• Fitting Bingham, Power-Law and Herschel-Bulkley models for hydraulics programs (API RP 13D).
• Formulation comparison in R&D and batch quality control.

FEATURES

• Twelve selectable speeds: 1, 2, 3, 6, 10, 20, 30, 60, 100, 200, 300 and 600 rpm.
• Standard R1 rotor / B1 bob / F1 torsion-spring geometry for direct API-compatible readings.
• Electronic speed regulation for constant shear rate under varying load.
• Compatible with a thermostatic heated cup for tests up to about 200 F (93 C).
• Height-adjustable sample platform with lock knob and scribed immersion line.

TECHNICAL SPECIFICATIONS

Measuring Principle	Coaxial cylinder, rotating outer sleeve
Test Speeds (rpm)	1, 2, 3, 6, 10, 20, 30, 60, 100, 200, 300, 600
Shear Rate	1.703 × rpm (1/s) with R1-B1 geometry
Rotor R1 / Bob B1 Radius	18.415 mm / 17.245 mm; bob length 38.0 mm
Torsion Spring F1	386 dyne-cm per degree of deflection
Sample Volume	Approx. 350 mL (to cup scribe line)
Test Temperature	Ambient up to about 200°F (93°C) with heated cup (option)

Values are typical for this equipment class based on API/ASTM practice and manufacturer literature (OFITE, Fann, Chandler); confirm against the Inmotion datasheet before use in a certificate or specification.

Main components (see Figure 1)

No.	Component
1	Readout display (dial / digital)
2	Speed selector switch
3	Rotor sleeve and bob
4	Sample cup
5	Adjustable platform and lock knob
6	Base and support column

Principle of operation

The cup is raised until fluid reaches the scribe line on the rotor. The motor drives the rotor sleeve at the selected speed, shearing the fluid in the annulus between rotor and bob. The viscous torque on the bob is balanced by the torsion spring, so the deflection (theta) is proportional to shear stress. Apparent viscosity in cP is 300 x theta / N (N in rpm). From the 600 and 300 rpm readings: PV (cP) = theta600 – theta300 and YP (lbf/100 ft2) = theta300 – PV.

Basic operating procedure

1. Stir the sample, fill the cup to the scribe line and record the sample temperature.
2. Raise the platform until the rotor is immersed exactly to its scribe line; lock the platform.
3. Select 600 rpm; wait for a steady reading (typically 10-15 s) and record it.
4. Repeat at 300, 200, 100, 60, 30, 10, 6, 3, 2 and 1 rpm, recording each steady reading.
5. For gel strength: stir at 600 rpm for 10 s, rest 10 s (or 10 min), then run at 3 rpm and record the maximum
deflection.
6. Calculate PV, YP and apparent viscosity; report the test temperature; clean and dry the rotor and bob.

Calibration and maintenance

• Check with certified Newtonian calibration oil at 300 and 600 rpm; re-calibrate if outside the manual’s
tolerance.
• Confirm the dial reads zero with the rotor running in air and inspect bob and sleeve for dents or wear.
• Remove and clean the rotor regularly to prevent scale and polymer build-up.
• Keep the instrument level and covered when not in use.

Safety precautions

• Keep fingers, hair and cables clear of the rotating sleeve.
• Wear gloves and eye protection; heated samples above 50 C can cause burns.
• Handle chemicals per SDS and dispose of used mud in line with site rules.

Reference sources