Title of Invention


Abstract The Stalagmo Droplet Counter can be used in the laboratory to determine the surface tension easily by using it along with the stalagmometer. It can be easily manufactured and the manufacturing cost is very low. It is very user friendly and easily fits in to the stalagmometer. It is also portable. Using this makes no negative effect on the experiment including the surface tension. It also can be easily understood how the machine functions enabling the experimenter to grasp the functionality of the experiment correct. The stalagmo droplet counter has no errors. This means the experiment can be conducted without repeat and with 100% accuracy. This machine bears no negative influence on the student in learning how the stalagmometer can be used to determine surface tension. It therefore makes the student grasp the experimental concept faster without any waste of time. It further eliminates the strenuous conducting of the experiment which results in lack of interest of students. I expect to manufacture this machine which simplifies this experiment and give it to laboratories for use.
Full Text

Surface tension in ordinary terms, is the inward attraction of molecules which are on the surface of a liquid. Due to the inward of attraction of the molecules on the surface, the surface acts as a thin film.
The Stalagmometer is an instrument which can be filled with a liquid, consisting of a miniature hole through which the liquid can drain very gently. The liquid that drains through, forms a bubble below the hole (Due to surface tension) which drops due to gravity after it forms. The size of the bubble which forms depends on the surface tension of the liquid.
The experiment is conducted so that the number of drops that drain through the Stalagmometer for a nown volume in it, is counted by naked eye for a very long period of time for around two hours. The drops amount
to approximately 500 droplets.
The counting process extends to two hours since the experiment should be repeated 3 times for the desired liquid and three times for water.
Then the surface tension is calculated by the equation below.
1) 1 = Surface tension of liquid
Dw = Surface tension of water
Ilw = Number of drops of water
^ 1 ~ Hw x Ql x Dw 111 = Number of drops of liquid
111 x dw dw = Density of water
Ql = Density of liquid

' Drawbacks of Ordinary Conductance of Experiment
1. The ordinary conductance of experiment requires prolonged periods of counting which is subject to human error. This error margin is very high due to the duration required in reducing the liquid until the correct volume is consumed.
2. Another problem faced here is the requirement to concentrate on the volume level in the Stalagnometer and if the marked level is exceeded the experiment should be conducted for a similar long period again.
3. Due to the loss of accuracy in counting the drops manually, the experiment needs to be repeated twice again to eliminate human error which intern requires more time.
4. Since this practical takes a long time to conduct because of the necessity of counting about 500 drops which takes about two hours to do, it is highly prone to error.
The STALAGMO DROPLET COUNTER counts the number of drops that fall, through a certain volume in the in the Stalagmometer. It stops counting when the desired volume level is reached and an alarm is sounded off to indicate the termination of counting. The number of drops being counted is displayed on a digital

A i vantages of Using the Stalagno Droplet Counter
1. There is no space for error in when using the Stalagmo Droplet Counter, thus there will be no
occurrence of error when counting droplets.
2. There is no necessity of keeping watch on the volume level as the Stalagmo Droplet Counter will
terminate the counting process by itself.
3. The Stalagmo Droplet Counter does not miss count on any droplets as a human would, thus eliminate
the necessity of repetition of experiment.
4. There is no requirement of human presence while the counting process goes on.
5. The Stalagmo Droplet Counter accounts to no chemical reactions on the unknown liquid of which the
surface tension is to be calculated. Hence there is no necessity of prior determination of the liquids
light sensitivity.
6. There is no interference on the Stalagmometer surface, which if happens may change the volume of
the droplet formed.
7. The Stalagmo Droplet Counter's sensors can easily fit into the stalagmometer and has no interference with the normal experiment's conductance.
8. The overall usage of the Stalagmo Droplet Counter is very simple and straight-forward.
A the STALAGMO DROPLET COUNTER is much accurate in counting, repetition is not required and the ci iductance of the experiment may be reduced to once for the liquid and once for water.

4. The calculator is switched on, and the buttons corresponding to "1" and "+" are pressed one after the other. This will start the counter which will start counting the drops falling and indicate it in its display.
5. If any dark solution is used, the sensitivit) of the sensor should be altered accordingly with the control knob meant for adopting the sensor to the liquid. This can be easily done because the correct function of the sensor shall indicated by the starting of counting.
6. After the liquid reaches the lower level of the stalagmometer, the alarm will sound off and the counting
process will be terminated automatically.
7. This process will be conducted with regard to both liquids, the control liquid (Water) and the one with the
anonymous surface tension.

This sensor is used to count the number of drops falling from the instrument. The technique used here is as follows. The sensor is light sensitive. It consists of a unit called the LDR(light dependent resistor). The resistance of the LDR changes with the amount of light incident on it. The resistance of an LDR decreases as the intensity of the light incident on it increases. The LED(light emitting diode) emits light in the direction of the LDR with a constant intensity. This changes each time a drop crosses the path of.it (This happens because as the light from the light source goes through the liquid it undergoes refraction, thus the intensity of the light changes (decreases)). This is recognized by Circuit B which is drawn below. This sensor unit fits easily fits into the stalagmometer.

For Sensor Unit 2, the same mechanism is used as in Sensor Unit 1. The only difference is that the intensity of the light will alter only when the water level drops below a certain point, thus terminating the counting process through connecting Circuit A. The signal sent to the circuit is this resistance value. (Due to the intensity variation from Water to Air). The sensor is set where the Stalagmometer termination point is located '(See Diagram). When a dark solution is used the intensity values involved here change. To change the sensor according to this, there is a knob which can regulate the intensity of the LED. This unit too, can he easily fitted into the apparatus of the experiment.
This is the alarm that will sound off when the counting process terminates. The counting process of the calculator will stop. A switch located in the panel may be pressed to switch off the alarm (This s lould be switched on when conducting the experiment again), How the alarm is connected with the other circuits is showed in the diagram below. This circuit is a simple alarm circuit that uses Integrated Circuit NE555.
The input of this unit is -230V AC. This is converted into 12V DC and distributed to all the circuits.
i CIRCUIT A - The signal coming from sensor 2 is recognized. According to this signal, the relay of the
circuit unit gets switched on. The circuits are set up so that, after the relay unit gets on, the counting circuit
gets disconnected and the alarm is switched on.
CIRCUIT B - The signal coming from sensor I, the circuit activates the relay in it. This relay sends signals to the calculator. This signal of the relay switch is sent to the "=" button of the calculator. According to the signals, the calculator counter increases by unity.

The stalagmo droplet counter can be used in the laboratories to simplfy the process involved in the experiment which uses the stalagmometer to
determine the surface tension. This machine counts the number of drops dripping from the
stalagmometer. It counts the number of drops 100% accurately eliminating the
necessity of repeating the experiment.
The counting process and the termination takes place fully
automatically without any human manipulation.

I claim the following:
1. The Stalagmo Droplet Counter counts the number of drops falling from the stalagmometer and displays it in a calculator screen.
2. The Stalagmo Droplet Counter terminates the counting process when the liquid reaches the terminal point.
3. The Stalagmo Droplet Counter indicates the termination of counting by an alarm.
4. There is no necessity of repeating the practical three times as in normal procedure of each liquid (Three times with water and three times with the unknown liquid).
5. This instrument uses LDR's (or else Photo Diodes ) and a Light Source to measure the intensity changes of light through the liquid and air which is used as the method for counting the drops and the liquid level.
6. This instrument has no interference what-so-ever to the ordinary experimental procedure maintained. This instrument has no effect on the liquid or its surface tension. No damage to the stalagmometer is caused by this instrument.
7. This instrument uses the phenomenon of light being exacted. This is used as a means of determining the liquid level.
8. The instrument also uses the fact that a liquid in general, is darker than air due to the density and/or color. The instrument can be adjusted through a knob to adapt to different values of light intensities transmitted, which varies due to the properties of the liquids used.
9. This instrument uses the phenomenon that a bubble (non-hollow) of water acts as a lens due to refraction at the point that it drops off the stagmometer.


492-CHENP-2007 AMENDED CLAIMS 11-11-2013.pdf


492-CHENP-2007 CORRESPONDENCE OTHERS 15-02-2013.pdf

492-CHENP-2007 CORRESPONDENCE OTHERS 29-04-2013.pdf


492-CHENP-2007 FORM-3 15-02-2013.pdf

492-CHENP-2007 OTHER PATENT DOCUMENT 11-11-2013.pdf

492-CHENP-2007 POWER OF ATTORNEY 11-11-2013.pdf

492-CHENP-2007 PRIORITY DOCUMENT 11-11-2013.pdf

492-chenp-2007 correspondence others.pdf

492-chenp-2007 form-3.pdf





492-chenp-2007-form 1.pdf

492-chenp-2007-form 26.pdf

492-chenp-2007-form 3.pdf

492-chenp-2007-form 5.pdf


Patent Number 258040
Indian Patent Application Number 492/CHENP/2007
PG Journal Number 48/2013
Publication Date 29-Nov-2013
Grant Date 28-Nov-2013
Date of Filing 05-Feb-2007
Name of Patentee WACKER CHEMIE AG
Applicant Address HANNS-SEIDEL-PLATZ 4, D-81737 MUNCHEN,
# Inventor's Name Inventor's Address
PCT International Classification Number C08J 3/03
PCT International Application Number PCT/EP05/08246
PCT International Filing date 2005-07-28
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 102004038148.8 2004-08-05 Germany