Huazheng HZ1731 User manual

HZ1731
Full Automatic Surface Tension
Tester
User Manual
Huazheng Electric Manufacturing (Baoding) Co., Ltd

Dear us er:
Th an k you for choosing HZ1731 Ful l Autom atic Sur fa ce Ten sion
Tester.
We hope that this instrume nt can make you r work easier and more
en jo ya bl e, so that you can get th e fee li ng of office aut om at ion in the test
an d an al ys is work.
Before us ing the inst rument, pl ea se re ad this manual, an d opera te and
maintain the instrume nt accordi ng to the ma nu al to pro lo ng its se rvice li fe .
"Just a light press, the test will be compl eted auto ma ti ca lly" is the
op er ating cha racteristics of this instrument.
If you are sat isfied wi th this inst rument, ple as e tel l yo ur co lleagues;
if you are not satisfie d with this ins trum ent, pl ea se call [phone] to
te ll you to ser ve you at all times- Baoding Huazheng Electri c Manufactu ring
Co. , Lt d., our comp an y will def initel y make you satisfied!

Contents
I.Summary................................................................................................................................................ 4
II.Instrument Introduction....................................................................................................................... 6
III.Instrument Operation........................................................................................................................10
IV.Attention............................................................................................................................................. 14
V.Appendix............................................................................................................................................. 15

I.Summary
This is HZ1731 full automatic surface tension tester including platinum plate method and
platinum ring method produced by . The surface tension is a basic property of liquid,
especially surfactant aqueous solution. Can measure the surface tension value of various
liquid quickly and accurately with physical method instead of chemical method. It has a
wide range of application. It can measure surface tension in hydropower sector to
strengthen supervision on the quality of insulating oil; it can measure and analyze the
surface tension value of various liquid in petroleum and chemical industry, scientific
research and education department.
1.1 What is the surface tension
Surface tension is the tension of liquid surface on any boundary line along the surface
due to the unbalanced molecular attraction. The resultant force on a molecule by
surrounding molecules inside the liquid is 0. However, that on the surface is not zero
because attraction on the molecule on the surface by gas phase molecular in the upper
space is smaller than that by the internal liquid phase molecule. The resultant force is
perpendicular to the liquid inside, resulting in automatic contracting trend in the surface of
the liquid and this contraction force is called surface tension.
Molecules inside the liquid are close to each other, maintaining a balanced distance
between molecules with attraction on a little farther distance and repulsion on a little
closer distance. It makes liquid molecules can only vibrate and rotate near the equilibrium
position unlike gas molecules that can diffuse infinitely. Liquid molecules near the surface
are only affected significantly by liquid inside. With uneven stress, the molecular in higher
velocity can easily escape from liquid and become steam thus resulting in molecule

distribution in the surface layer (a thin liquid layer contacting gas ) is sparser than internal.
Intermolecular repulsion in surface layer decreases as the distance between each other
increases. Intermolecular attraction prevails in surface layer. Mutual traction of any two
parts in surface layer prompts a shrinking trend in surface layer. The liquid surface tends
to reduce as much as possible due to the effect of surface tension, so the small droplet in
the air is in spherical shape.
1.2 Platinum plate method)
When the platinum plate is immersed in the liquid to be measured, the surface tension will
occurs around the platinum plate. The surface tension of the liquid will try to pull plate
down. When surface tension of the liquid and other related stress are equal to the
equilibrium force, the platinum plate will stop. At this time, the balance sensor will measure
the immersion depth, and convert it to the liquid surface tension values.
Steps:
(1) Raise the platform;
(2) When the bottom of the platinum plate contacts with the liquid surface, the equilibrium
value is measured by the sensor and converted to the surface tension value to display.
1.3 Platinum ring method
A circular membrane between testing part and the liquid sample will be formed with this
method.
Steps:
(1) Immerse the platinum ring gently into liquid inside.
(2)The platform descends and then a bubble film forms below the platinum ring and
eventually leaves it.
(3)The equilibrium value is measured by the sensor and converted to the surface tension
value to display.
1.4 Comparison
①The platinum plate method measures the change of liquid surface (or interface) tension
over time. Platinum plate is always contacting with the liquid to be tested and as long as
the liquid surface tension changes, the test value will change. The curve of surface
tension over time can be observed with data processing software.
②The platinum plate method can easily measure the surface tension of medium and high
viscosity liquid; The platinum ring method requires the ring to ascend and the ring is acted
upon surface tension and viscous force in that process.
③The platinum plate method has high precision. Platinum plate is harder to be deformed
than ring. Irregular and uneven round ring may affect test precision.

II.Instrument Introduction
2.1 Technical index
Model
HZ1731
Resolution (mN/m)
0.1
Measure range(mN/m)
0-1000
Repeatability (mN/m)
0.1
Accuracy(mN/m)
0.1
Balance precision(Domestic)
1/1,000
Weighing system
electromagnetic force balance
Test mode
both platinum plate and platinum ring method are
provided;
Display mode
5-inch color touch screen
Measure mode
touch operation;
automatic sample stage lifting; automatic conversion
Measure time
10 secs for Plate Method, 50 secs for Ring
Accuracy correction
automatic one provided
Option
data processing software
2.2 Function
Platinum plate method and platinum ring method for wide appliance
Automatic and intelligent operation and data acquisition minimizing artificial operation
error
Imported key parts(including sensors) making test data in good accuracy and
repeatability
Data automatic generation, storage and printing
Stable operation with low noise
2.3 Preparation
Please make sure the following items have been completed before assembly.
①The lab should be clean at constant room temperature.
②Make sure water available for apparatus cleaning.
③Make sure open flames available to burn platinum ring and platinum plate.
④Install ground socket and plug in 220V power;
⑤Check the instrument appearance and let it stand still for 1-2 hours

2.4 Instrument panorama
2.5 Touch screen
Home
Parameter setting

Testing interface(platinum plate）
2.6 Software installation
(Both touch screen and software operation are available in usage of If do not use
software, please ignore this part. But the touch screen can only display the data at a time
and can't bring up the history data.)
Preparation: connect the software CD and software dog; connect the power cord with a
computer and start up.
①Software installation: Open the installation CD, which contains the PZ series of
surface tension control system, USB serial port driver and CH340 driver (USB serial
driver)
②Driver installation: Select the "USB serial driver", select the suitable driver according to
the computer system:

"PL-2303 Driver (Windows 7 32)" for the win 7, 32 bit operating system;
"PL-2303 Driver (Windows 7 64 WIN8)" for the win 7 64 bit /win 8/win 10operating system;
"PL-2303 Driver (Windows 98 2K XP") for the win XP operating system;
“PL-2303 Driver (Windows Vista32)” for the win Vista operating system
When using win 764 /win 8/win 10 operating system, open the “PL-2303 Driver (Windows
764 WIN8)” folder, select the “LU105T-Win8.8.0 Driver” file to install
“PL2303_Prolific_DriverInstaller_v1.8.0 ”, and click the next step.
There is a single driver “PL-2303 Driver Installer” in the corresponding folder in other
systems.
③CH340 driver (USB serial driver) installation: Double click "CH340 driver (USB serial
driver)", select the installation
④Right click “my computer”, open the device manager, and check the port- if there is a
yellow exclamation mark, right click "Prolific USB-to-Serial Comm Port", select "update
driver software" and "browse the driver files on the computer" to find the driver in the
CD-drive".
If it displays update state as the fig. above, no update is required.
⑤Select the corresponding port number in the software interface and open it(if it has
been opened, ignore this step).
Chose the port com (the port com number in the "device manager": Right click on the
"computer", click "device manager" in the "management", chose the "Port"), then click
“Open”.

III.Instrument Operation
If the platinum plate / ring or beaker is not clean, the measured value will have error with
poor repeatability, being unstable or having continuous increase or decrease. Please keep
clean.
For example, when testing water, if you touch the water with finger the tension value will
be smaller, because the finger oil can change surface properties of water. Please keep the
platinum plate/ring and beaker clean (ultrasonic cleaning then drying before use).
3.1 Instrument calibration
1) Level calibration
Let the device stand still for 1-2 hours, observe whether the calibration bubble on the
back is in the middle. If not, there is no level.
Calibration method: turn adjustment knob until the bubble is in the middle of level.
2) Scale calibration
Put on the supporter. When screen is stable, press "TARE" to reset, then it shows “0.0000
g”. Long press "CAL", then "CAL" and didi sound shows, flashing 100.0000 g. If it shows
100g when 100-g weight is put, the correction is success (please don’t
touch the weights by hand directly)
Note: In correction, long press "MENU" and "CAL", then "CAL" and didi sound shows,
flashing 20.0000g.put into the 20-g weight and make correction.
3) Temperature calibration
Click "Parameter setting" on the touch screen.

Temp correction = actual room temp- display temp
3.2 Parameter calculation: platinum ring operation
Calculate parameters with distilled water and high purity ethanol before
the test(For example, if distilled water parameters need correction and the
sample is ethanol, just replace the test liquid with distilled water in operation
steps.)
①Install the holder and make it near the inside, avoiding directly leaning on
the connecting rod between sample stage and host.
②Set parameter: Click "Parameter setting", set "Rise speed" "Fall speed". Because liquid
membrane tension occurs when sample table falls, fall speed should be slow as far as
possible.
③Clean beaker, then make infiltration: Wash a beaker with distilled water, and make
infiltration with test liquid-a little ethanol beaker, and pour it out.
④Let sample stage go down and put into liquid to be tested: Click "Ring method",
"Platform fall" to make platform down to the lowest and stop automatically. Add ethanol
into the beaker after infiltration and put the beaker on the platform.
⑤Burn platinum ring and reset: Gently remove the ring with tweezers (the ring is round;
deformation should be avoided), burn it for 20-30 secs to red with alcohol lamp and hung it
on the hook. Press "TARE" button on the scales and "Reset" on the touch screen.
⑥Let sample stage go up. Press "Platform rise". When the ring is emerged in the depth of
3-5 mm into ethanol, press "Platform stop".
⑦Start measuring: Click the "Test" in the "Ring method" interface. Then sample
stage began to decline and collect data. When collection is finished, the device stop
automatically and the peak tension is the current surface tension value.

⑧Continue tests. Raise platform directly, repeat steps⑥⑦ until the data is generally
stable(Usually, we take the average value of the third, fourth and fifth experimental data in
the current test; several times tests are needed for sample of high viscosity.)
⑨Repeat tests. Please clean the ring with slowly running clear water before burning (If
possible, please use the ultrasonic water.) to prevent the ring from being destroyed by
material difficult to burn in the liquid to be tested. Repeat steps⑤⑥⑦⑧.
⑩Change the ethanol to distilled water. Repeat steps③④⑤⑥⑦⑧⑨.
3.3 Parameter calculation: platinum plate operation
Calculate parameters with distilled water and high purity ethanol before the test (For
example, if distilled water parameters need correction and the sample is ethanol, just
replace the test liquid with distilled water in operation steps)
①Install the holder and make it near the inside, avoiding directly leaning on the
connecting rod between sample stage and host.
②Set parameter. Click "Parameter setting", set "Rise speed" "Fall speed". Because liquid
membrane tension occurs when sample table falls, fall speed should be slow as far as
possible.
③Clean beaker and make infiltration. Wash a beaker with distilled water, and make
infiltration with test liquid-a little ethanol beaker, and pour it out.
④Let sample stage go down and put into liquid to be tested. Click "Ring method",
"Platform down" to make platform down to the lowest and stop automatically. Add ethanol
into the beaker after infiltration and put the beaker on the platform.
⑤Burn platinum plate and reset. Light the alcohol lamp. Gently remove the plate (there is
a right angle between the plate and the holder; make sure the platinum bottom is on the
level) and hold it with tweezers, burn it to red (don’t burn the holder; the fire is generally 45
degrees angle to the horizontal) and hang it on the hook gently. Press "TARE" button on

the scales and "Reset" on the touch screen.
⑥Let sample stage go up. Press "Platform rise" on the touch screen. When the bottom of
the platinum plate is 3~5 mm apart from the ethanol liquid level, press the "Platform stop"
on the touch screen.
⑦Start measuring. Click the "Test" on the "Platinum plate method" interface. The
sample stage began to rise, and collect data, when after the data collection, instrument
and automatic stop, the tension is the surface tension value at this time
⑧Continue tests and repeat step⑥until the data is basically stable (Usually, we take the
average value of the third, fourth and fifth experimental data in the current test; more tests
are needed for sample of high viscosity).
⑨Repeat tests. Please clean the plate with slowly running clear water before burning (If
possible, please use the ultrasonic water.) to prevent the plate from being destroyed by
material difficult to burn in the liquid to be tested. Repeat steps ⑤⑥⑦.
⑩Change the ethanol into distilled water and repeat steps ③④⑤⑥⑦⑧.
3.4 Parameter calculation
Check the Index Table 5.2 or 5.3 according to the current temp, enter the ideal and
measured tension value of distilled water and ethanol and calculate correction coefficient
respectively.
1) Using touch screen
①Click "Calibration of water", input standard and measured values, then click" Ring
calibration".
②Click "Calibration of ethanol" , input standard and measured values, then click" Ring
calibration".

Press "ring correction coefficient" in "set parameter" to calculate the correction data.
Note: with Plate Method, please select "plate correction "to calculate" plate correction
coefficient".
2) Using software:
Input the ideal and measured tension value of distilled water and ethanol on the interface
and then calculate correction coefficient respectively.
3.5 Actual operation
Replace the ethanol or distilled water with the liquid to be tested and repeat the above
operation (3.2 for ring or 3.3 for plate)
IV.Attention
4.1 Low / high value
Platinum plate or ring is not burnt clean (most likely); the beaker is not clean.

No return to zero of correction before the experiment; inaccurate reset or no reset
after a platinum plate or ring being hanged.
Sample contamination in wrong operation process
The characteristic of liquid to be tested is changing with time. The liquid should be
stirred evenly with the same ratio and in full rest.
The wetability of the liquid is not very high, it has viscosity or volatility.
4.2 Poor repeatability
Platinum plate or ring is not clean.
The characteristic of liquid to be tested is changing with time. The liquid should be
stirred evenly with the same ratio and in full rest.
4.3 Platinum ring / plate maintenance
To keep the experiment accuracy, please make sure platinum ring is standard round.
Please put deformed one back to the container and gently smooth it with tweezers. If the
ring is deformed badly or damaged, please buy a new one.
Check whether the platinum ring on the holder is parallel to the liquid level.
V.Appendix
5.1 Surface tension values of some liquid at 20 ℃
Some of the liquid γ (20℃)
liquid
γ（mN/m）
liquid-steam
water-liquid
water
72.75
octane
21.69
51.68
dodecane
25.44
52.90
hexane
27.46
53.77
benzene
28.88
35.0
tetrachloromethane
26.77
45.0
octanol
27.53
8.5

butanol
24.6
1.6
aniline
42.9
5.9
aether
17.0
10.7
ethyl acetate
23.9
3
mercury
284
426
5.2 Density, viscosity and surface tension in the air interface of
water at different temp
t/℃
d/(g/cm3)
η/(10-3 Pa.s)
γ/(mN/m)
0
0.99987
1.787
75.64
5
0.99999
1.519
74.92
10
0.99973
1.307
74.22
11
0.99963
1.271
74.07
12
0.99952
1.235
73.93
13
0.99940
1.202
73.78
14
0.99927
1.169
73.64
15
0.99913
1.139
73.49
16
0.99897
1.109
73.34
17
0.99880
1.081
73.19
18
0.99862
1.053
73.05
19
0.99843
1.027
72.90
20
0.99823
1.002
72.75
21
0.99802
0.9779
72.59
22
0.99780
0.9548
72.44
23
0.99756
0.9325
72.28
24
0.99732
0.9111
72.13
25
0.99707
0.8904
71.97
26
0.99681
0.8705
71.82
27
0.99654
0.8513
71.66
28
0.99626
0.8327
71.50
29
0.99597
0.8148
71.35
30
0.99567
0.7975
71.18
40
0.99224
0.6529
69.56
50
0.98807
0.5468
67.91
60
0.96534
0.3147
60.75

5.3 Density, viscosity and surface tension in the air interface of
ethanol at different temp
t/℃
d/(g/cm3)
η/(10-3Pa.s)
γ/(mN/m)
20
0.795
1.18
22.3
30
0.785
0.97
21.2
40
0.777
0.82
20.4
50
0.765
0.69
19.8
60
0.755
0.58
18.8
70
0.746
0.505
18
80
0.735
0.44
17.15
90
0.73
0.38
16.2
100
0.716
0.34
15.2