Rheometer: Principles, Brand,Usage, Common Faults, and Maintenance

1. Principles of Rheometer

A rheometer is an instrument used to measure the rheological properties of fluids under different conditions. Its measurement principles are based on applying stress or strain to the fluid and measuring the fluid’s response under these conditions. The specific principles include:

• Rotational Rheometer: By rotating the measuring element (such as a rotor or cone), shear strain is generated in the fluid, and the required torque or resistance is measured to determine the fluid’s viscosity, shear stress, and rheological characteristics.
• Capillary Rheometer: The fluid flows through a capillary tube, and its viscosity and rheological behavior are studied by measuring the pressure drop and flow rate.
• Oscillatory Rheometer: Oscillatory strain or stress is applied to the fluid, and the fluid’s elastic modulus, viscous modulus, and damping characteristics are measured.
• Tensile Rheometer: Tensile strain is applied to the fluid, and its tensile properties are measured.
• Cone-Plate Rheometer: Using a cone-plate structure, shear strain is generated in the fluid, and the fluid’s viscosity and rheological characteristics are measured.

2. Usage of Rheometer

The usage of a rheometer typically includes the following steps:

Startup Preparation:

• Turn on the air compressor (air valve closed).
• Allow air pressure to rise to the standard value (e.g., 5-8 bar).
• Open the air valve.
• Turn on the constant temperature water bath (ensure external circulation mode).
• Turn on the main power supply and confirm the status of the main unit.
• After self-check, press “ONLINE” to turn off the indicator light and initialize the displacement.
• Open the rheometer software, press “ONLINE” to turn on the indicator light, and initialize the connection.

Experimental Operation:

• Install the measuring jig and sample.
• Set experimental parameters such as temperature, rotation speed, stress, etc.
• Start the experiment and record data.

Experiment Completion:

• Remove the measuring jig and clean the jig and cylinder.
• Turn off the main power supply, water bath, and air compressor.
• Organize the experimental instruments and equipment.

3. Common Faults and Maintenance Methods

The rheometer may encounter the following common faults during use, and the corresponding maintenance methods are as follows:

• Sample Not Flowing or Unstable Flow:
  • Cause: Insufficient sample volume, too thick sample, bubbles in the sample, or sample not fully melted.
  • Maintenance Method: Increase sample volume, reduce sample thickness, centrifuge or filter the sample, ensure the sample is fully melted at the test temperature.
• Poor Repeatability of Test Results:
  • Cause: Unstable sample properties, instrument fault, improper operation, or environmental factors.
  • Maintenance Method: Use a more stable sample, inspect and repair the instrument, recheck the operation process, control environmental factors.
• Large Deviation in Test Results:
  • Cause: Uneven sample, improper operation, instrument fault, or inaccurate test conditions.
  • Maintenance Method: Use a more uniform sample, recheck the operation process, inspect and repair the instrument, adjust test conditions.
• Instrument Unable to Start or Automatically Stops:
  • Cause: Power failure, internal instrument fault, safety protection mechanism.
  • Maintenance Method: Check the power plug and power cord, inspect and repair the internal instrument, check the safety protection mechanism and adjust.
• No Display or Abnormal Display on the Screen:
  • Cause: Internal instrument fault, power failure, connection issue.
  • Maintenance Method: Inspect and repair the internal instrument, check the power plug and power cord, ensure the connection cables are properly inserted.
• Abnormal Sound or Odor During Testing:
  • Cause: Abnormal sample properties, instrument fault, improper operation.
  • Maintenance Method: Recheck the operation process, inspect and repair the instrument, check the sample properties.
• Mechanical Fault:
  • Cause: Broken, worn, or stuck transmission system.
  • Maintenance Method: Inspect and replace transmission components, ensure the transmission system is smooth.
• Electrical Fault:
  • Cause: Power failure, poor wire contact, control circuit fault.
  • Maintenance Method: Check the power supply, wires, and control circuit, perform necessary repairs or replacements.
• Temperature Control Fault:
  • Cause: Fault in the temperature control system.
  • Maintenance Method: Inspect and repair the temperature control system, ensure accurate temperature control.
• Sensor Fault:
  • Cause: Damaged or faulty sensor.
  • Maintenance Method: Inspect and replace the sensor, ensure accurate data collection.
• Software Fault:
  • Cause: Fault in the control software.
  • Maintenance Method: Reinstall or update the software, ensure the software runs normally.

If any issues are encountered during the use of the rheometer, it is recommended to promptly consult professionals or the manufacturer for resolution.

4. Brands and Models of Rheometers Repaired by Longi Electromechanical

• Anton Paar:
  1. MCR 302
  2. MCR702 MultiDrive
  3. MCR 502 WESP
  4. MCR502
  5. MCR72
  6. MCR 92
• TA Instruments:
  1. Discovery HR-3
  2. Discovery HR-2
  3. Discovery HR-1
  4. DHR-1
  5. DHR-2
  6. DHR-3
  7. AR-G2
• Malvern Panalytical:
  1. Kinexus Pro+
  2. Kinexus Ultra+
  3. Kinexus Lab+
  4. Rosand RH2000
  5. Rosand RH7
  6. Rosand RH10
  7. Rosand RH50
• Brookfield (Ametek Brookfield):
  1. RSX Rheometer
  2. RST Rheometer
  3. DVNext Rheometer
  4. PFT Powder Flow Tester
  5. CT3 Texture Analyzer
• Thermo Scientific:
  1. HAAKE MARS 60
  2. HAAKE Viscotester iQ
  3. HAAKE RotoVisco 1
  4. HAAKE RheoStress 1
• Anton Paar Physica:
  1. MCR 302 WESP
  2. MCR 502 TDR
  3. MCR 102
  4. MCR 302 MultiDrive
• ATS RheoSystems:
  1. RST Controlled Stress Rheometer
  2. Viscoanalyzer, EML Rheometer
• Rheosense:
  1. m-VROC
  2. e-VROC
  3. microVISC
• Thermo Fisher Scientific:
  1. HAAKE Viscotester 550
  2. HAAKE MARS iQ, HAAKE Viscotester 3
• Reologica Instruments:
  1. Stresstech HR
  2. Kinexus DSR-E
  3. Bohlin Gemini 2

Longi Electromechanical has nearly 30 years of experience in repairing rheometers and can quickly repair various types of instruments. Additionally, we recycle and sell various used rheometers. Welcome to consult.