Torque balance is a precision instrument that uses the torsional torque of metal wire (or quartz wire) to weigh the principle of balance between the gravity of the object being measured, and the core is used to measure tiny masses. It adjusts the reaction moment generated by the torsion angle of the metal wire to achieve balance with the gravity of the sample, and then reads out the sample quality, which has the characteristics of simple structure and high sensitivity, and is suitable for accurate weighing of trace or semi-trace samples.
type
According to the material - it can be divided into metal wire torque balances (commonly used copper alloys, stainless steel wires, strong bearing capacity) and quartz wire torque balances (quartz wire has good elasticity and high stability, suitable for higher precision micro weighing).
By range - including semi-micro torque balances (usually 10-100 mg, accuracy 0.1 mg) and micro torque balances (less than 10 mg, accuracy 0.01 mg and above).
According to the usage scenario - there are laboratory conventional torque balances (suitable for daily micro weighing) and special torque balances (such as explosion-proof type, moisture-proof type, suitable for weighing needs in special environments).
Test principle
The core principle of torsion balances is "moment balance". The elastic wire (or quartz wire) inside the instrument is fixed at one end and connected to the beam at the other end, where the sample can be placed. When the sample is placed, gravity will deflect the beam and drive the wire to twist. When the wire is torsional, a reaction moment proportional to the torsion angle is generated, and when this reaction moment is completely balanced with the moment generated by the sample's gravity, the beam stops deflection. The torsional angle of the wire is read by a dial or optical system, and combined with the coefficient of elasticity of the wire, the mass of the sample can be converted.
Fields of application
Laboratory analysis - used for weighing trace samples in chemical and biological experiments, such as quality testing of small quantities of reagents, biological tissue samples, and powder samples.
Jewelry and precious metals - used for mass measurement of tiny jewelry and precious metal particles to meet the needs of high-precision weighing.
Environmental testing field - weighing trace pollutant particles in soil and water quality to assist environmental monitoring experiments.
Common faults and solutions
Unstable needle swing: It is often caused by environmental vibration, airflow interference or loose beams. Solution: Place the balance on the anti-vibration table, close the doors and windows to reduce airflow, and check and tighten the connection of the beam.
Inaccurate weighing results: This could be due to elastic fatigue of the wire, uncalibrated zeros, or worn weights. Solution: Replace the elastic wire with a new one, recalibrate the zero point, use standard weights to calibrate and replace the wear weights.
Unable to achieve equilibrium: mostly caused by sample placement offset and wire stuttering. Solution: Adjust the sample to the center of the beam, check whether the wire is entangled with foreign objects, clean it up and re-operate.
Blurred scale readings: Caused by optical system offset or dial contamination. Solution: Adjust the position of the optical lens and wipe the dial stain with a dust-free cloth.
How to choose
According to the sample quality selection, the semi-micro sample selection range is 10-100mg, and the microsample selection range is less than 10mg.
For conventional experiments, select metal wire models with an accuracy of 0.1mg, and for high-precision experiments (such as material research and development), select quartz wire models with an accuracy of 0.01mg and above.
Ordinary laboratories should choose ordinary models, and wet, dusty or explosion-proof environments should choose special protective torsion balances.
Give priority to models with good elasticity stability, clear scales, and convenient calibration, while considering brand reputation and after-sales calibration services.
summary
Torque balance is a precision instrument for micro weighing based on the principle of torque balance, which can be divided into various types according to material and range, and is widely used in laboratories, jewelry and other fields. When using, attention should be paid to troubleshooting common faults such as vibration interference and accuracy deviation, and the selection should be combined with sample characteristics, precision requirements and use environment to ensure accurate and reliable weighing results.
