Float project

To download project report click on "GO" button

ID ca-pub-2509859738788173

Introduction

                                                                                                                                                                          

                                              

 

Today I am going to talk about a very useful project that I had taken up. It is called the Water Level Indicator. Nowadays everybody has overhead tank at their homes. But everyone who has a water tank above knows the kind of problems that they face. Firstly there is no system to track the water in the tank. Then there come a secondary problem that is when their water pump is started they have no idea when it gets filled up and sometimes there are situation where the pump keeps on pumping water to the tank and the water starts spilling out from the tank. There is wastage of energy as well as wastage of water.

Float switch

          A float switch is a device used to detect the level of liquid within a tank. The switch may be used in a pump, an indicator, an alarm, or other devices.Float switches range from small to large and may be as simple as a mercury switch inside a hinged float or as complex as a series of optical or conductance sensors producing discrete outputs as the liquid reaches many different levels within the tank. Perhaps the most common type of float switch is simply a float raising a rod that actuates amicroswitch.Opened float switch from a sump pump float switch on float switch off A very common application is in sump pumps and condensate pumps where the switch detects the rising level of liquid in the sump or tank and energizes an electrical pump which then pumps liquid out until the level of the liquid has been substantially reduced, at which point the pump is switched off again. Float switches are often adjustable and can include substantial hysteresis. That is, the switch's "turn on" point may be much higher than the"shut off" point. This minimizes the on-off cycling of the associated pump.Some float switches contain a two-stage switch. As liquid rises to the trigger point of the first stage, the associated pump is activated. If the liquid continues to rise (perhaps because the pump has failed or its discharge is blocked), the second stage will be triggered. This stage may switch off the source of the liquid being pumped, trigger an alarm, or both.

                                                                

Later History

This project that I had taken up is the result of long hours of research of work at the Internet as well as long hours of thinking. I had made various versions of the projects earlier but at last I came up with this final product. I bet this has been tested and I can now firmly say that the model would work flawlessly without any complains for years. I am saying this as I have installed this models to various houses in my neighborhood and all are working fine without any maintenance. And indeed this model is admired by all who uses it.

The Situation
The house where I live in has an overhead tank which is about 30 feet from the ground level. I was getting bored going up the rooftop to check whether the tank has filled or the water level was below to start the pump. I had to do this again and again. Then I sought for a solution. I always used to think of the possibilities of how can this problem be tackled in an electronic way. After years of research and by trial and error,  I found one and wanted to put whatever I have done out here so that it may be helpful to someone who has a overhead water tank at their homes.

                                                       

Basically the unit is made up of various sensors acting as a switch. Let me explain in a simple way. What happens is when you turn on you water pump, the water starts to get pumped from your underground reservoir  or from your underground water supply from the pipes to your water tank. In the tank there is a set of sensors( to be precise there are 7 sensors), in the water tank. Just think them as a switch, as the work of the sensor will be to connect a circuit. I will explain in details in my instructables. So the water starts to get filled in the tank and when the water level in the tank starts to rise up, what happens is that the sensors that is installed in the tank starts to get activated one by one indicating the water level in the tank. And finally when it reaches to its top most sensor, there will be a visual display as well as a sound from the unit indicating that the water has filled in the tank and one can be alerted that the tank has been filled up and the water pump has to be switched off saving the electricity bill as well as over flow of water from the tank.
                                                       

Desining

                                                                                                                                         

There are Four parts in this project:-

(i) The Sensor Part
It is generally a fixed support inside the tank having some nuts and bolt with wires coming out.
(ii) The Circuit Part
It comprises the brain of the module, where in all the various inputs from the sensors are fed. It is the unit from where you will get all the information of how much of water is in the tank.
(iii) The Power Supply
It is the part where in you will be converting the A/C voltage to a regulated voltage of 5V to the Circuit.
(IV) The Buzzer Part
It is responsible for bringing up the sound when the water level fills up in the tank. It will also be having a speaker or a buzzer to alert.

It has numerous transistors acting as a switch and e switch gets activated when the sensors tell them to. 

The heart of the circuit is the transistors BC 547. There are total7 transistors in the circuit and each one will be sensing the level of water present in the overhead water tank. There is one extra power LED without a transistor and that is because this Red LED will be telling us two things. Firstly when you power the unit it will be monitoring the power present in the unit and secondly it is also the indicator telling you that there is no water at all present in the tank. As because the water level is below the No. 1 (as shown in the circuit) sensor, no LED's will be lighting up, but only for the one Red LED. Therefore when you switch on your unit if you see only one Red LED lighting up then you know that the is no water present in the tank and therefore you should make you water pump on.
Then as shown in the figure i have given all the LED's in various color. Starting from the beginning is 

  1) Red LED (Indicating no water in the tank as none of the sensors are getting contact with the water)

  2) Red LED ( Level 1, indication very low water in the tank )

  3) Yellow LED (Level 2, indication of low water)

  4) Yellow LED (Level 3, indication of 1/4 of water in the tank)

  5) Green LED (Level 4, indication of half of water in the tank)

  6) Green LED (Level 5, indication of more than half of water)

  7) Green LED (Level 6, indication of nearing filling up the tank)

  8) Blue LED(Level 7, Full indication of tank and buzzer comes on)

Now as the water starts to rise up the sensors starts to get in contact with the water and the transistors are activated and there is a flow of current in the transistors making the LED's light up. Here in between the transistor and the LED there is a current limiting resistor 470 ohms, the job of the resistor is to checks that the LED does not get over voltage and destroy the LED. The transistor is biased by a 470K resistor with the ground and the sensing part is taken from the collector with a 33 ohms resistor going directly to the tank. As i have shown in the diagram the signals are drawn in the Green color. There by you can follow the LED's as they light up from Red to Yellow and then Green and finally to Blue making a sound.

The Buzzer Part
Here you can add any of the normal buzzers that are readily available in the market and if  it is not then you can make yourself with a simple 555 IC. I am giving a small circuit diagram, it is really simple to make and there are minimum parts. It is a simple audio oscillator. I have also provide a circuit diagram here but if you are able to manage a buzzer then no need to assemble this circuit.

The Power Supply
This section contains a transformer converting the mains voltage 220V bring down to 9V. There is a bridge rectifier containing 4 diodes and making the Alternating current to Direct Current. After the filtering the voltage is then directly fed to the voltage regulator (7805) with a filtering capacitor. From the regulator IC the output voltage is then again filtered with a capacitor and is fed to the circuit. This comprises the power supply of the device.

This completes the electronic part of the project and now i will be going to the sensor part, which is also made easily.

Working principle

                               

                                                                                                                                        

Float level method of liquid level measurement. The float is attached to the end of a string which rest on a sprocket pulley.

The other end of the string is in tension by a counterpoise. As the liquid level changes the float rises or falls correspondingly and the pulley rotates.

The pulley connected to spindle and spindle with pointer. Pointer moves over a calibrated scale which directly shows the liquid level.

Q:How does a float switch work?

Answer:

            There are many different types of float switches, some of which are mercury switches that activate by allowing the liquid metal to complete the circuit, and others that are simple floats connected to a micro switch that activates the device. They are common in sump pumps, dishwasher sand other appliances. Continue Reading Keep Learning What is a three-way electrical switch? How does a coolant-level sensor work? What is a relay switch used for? Full Answer With a sump pump, the float switch detects flooding in the sump. It activates the switch that starts the pump to operate. As the pump empties the sump, the float drops and the switch stops the pump from operating. In a dishwasher, the switch activates a valve to allow the appliance to fill with water. Once the liquid reaches the preset level, the switch causes the valve to close to prevent flooding. In septic systems where gravity flow is not an option, installers often use a pump system. This system includes three mercury float switches. The lowest switch is set to stop the pump. The middle switch activates the pump. Under normal circumstances, the fluid level remains between these two switches, keeping the pump submerged in effluent water to protect it from corrosive sewer gas. However, if the pump stops working, the tank fills to the point of activating the third switch, causing an alarm to sound, warning the home occupant of a problem.

Other method of level measurement:

1.  Capacitive method
2.  Radiation method
3.  Capacitive method

Using the variable area of capacitor, the liquid level can be measured and it can be shown that for liquids the capacitance of the transducer is directly proportional to the level.

A cylindrical capacitor probe with two electrodes of diameter d1 and d2 (inner) is inserted into the tank containing dielectric liquid of permittivity £1.

For a total tank height (and of the capacitor probe) H, and liquid height h, the capacitance is easily calculated as,

            C   =   2π [(£1 - £2) h + £1H/ln (d1 / d2)] Z

                =   A1 + A2 h

If the liquid is conducting, the electrodes may be coated with a dielectric material.

Often the tank is used as outer electrode and a cylinder rod is centrally inserted to act as the inner electrode.

The accuracy of the method depend also on the accuracy of capacitor measurement which is usually done by a bridge circuit.

   

Ø      Radiation method

A typically B-ray technique for liquid level measurement in diagram

A radiation source is installed at the tank as shown diagram with a detector (usually a Geiger Muller counter) mounted on top with the counting facility or 'average of count' system.

In the liquid radiation is absorbed whereas on the top of the liquid, in air medium, this absorption is negligibly small.

The intensity of radiation, I , recorded by the detector counter system is

Given by,

     I = Ioe-ux 

                                                  

        Where x is the length of the liquid medium through which the radiation passes, Alfa is the absorption coefficient and Io is the unabated radiation intensity emanating from the source.

We have, 

                          H = 1/Alfa ln [Io/I] sin 0(theta)

The relationship between h and I is obviously not linear.

This method applicable for solid as well.

                                        

Biblography

                                                                                                                             

1} Referring textbook

2} www.instructable.com

THANK  YOU FOR VISIT MY BLOG 

Hi friends if you want to share your project or seminar with other students to help them into there project or seminar then plese kindly share with us .

To share your  projects send attachments of  project to chaudharimohit39@gmail.com