I. Main functions and features
Intermolecular Forces formed liquid surface tension.Numbers of tension reflect on liquid sample’s physics and chemical properties, it is one of the most important index to product quality. Intermolecular Forces formed liquid surface tension.Numbers of tension reflect on liquid sample’s physics and chemical properties, it is one of the most important index to product quality.
1.It used electromagnetic force -balance-type transducer, improving the accuracy of the measurement
2.Demarcated one point and you can adjust the instrument, and it's very convenient.
3.the instrument can show current weight values and tesion Equivalence
4. Integrated temperature detection circuit, automatic temperature compensation for test results;
5. 240×128 dot matrix LCD screen, no logo button, with screen protection function;
6. Historical records with time stamps, store up to 255;
7. Built-in high-speed thermal micro printer, beautiful and fast printing, with offline printing function;
8.the instrument has RS232 interface equipment,it can connect to computer,and it convenient for data processing.
II. Technical characteristics
Measuring range： 0-200mN/m
accuracy：0.1%( test result)±0.1 mN/m
mains voltage：AC220V±20% 50HZ±10%
maximum power dissipation：20W
suit ambient temperature：10～30℃(25℃the best)
suit ambient humidity：≤85% RH
When the platinum ring is pulled up from the "liquid-gas" interface or the "liquid-liquid" interface, a circular liquid column membrane will be formed under the platinum ring. As the ring continues to rise, the liquid column membrane ruptures. In this process The maximum force value detected by the electromagnetic force balance sensor is converted into the tension value by the following formula.
M=mg/2L L= Pt circle’s circumference
The test value will effect by many factor:
（1）Pt circle’s average radius and the Pt wire’s radius
（2）Liquid sample and other medium’s density contrast
（3）The purity of the liquid, the electrolyte impurities will seriously reduce the tension value.
Since the liquid column formed at the platinum ring is not cylindrical, a correction factor F must be introduced. The calculation formula for the correction factor F given by Zuidema and waters:
The final result after correction is:：
In the formula:
P0------ Lower liquid density, unit: g/mL
P1------Upper liquid density or gas density, unit: g/mL
Rs------the average radius of platinum wire, unit: mm
Rh------average radius of platinum ring, unit: mm