Flowmeter

Flowmeter

Project developed by Ajit Thachireth & Mayank Moon

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Abstract

1. Flowmeters are the devices that are used to measure the flow of liquid & gases that pass through them.
2. Flowmeter that measure the flow by calculating the amount of liquid flown in unit time are called velocity flowmeter. This type of flowmeter typically provides with velocity of flow (ex: 10 litres per minute).
3. Volumetric flowmeter on the other hand measure the total amount that has been discharged. For example this flowmeters may be utilized to know the amount used in house over a month(100 l).
4. This project is focused to have a flowmeter that has the ability to act both as velocity flowmeter & volumetric flowmeter. So, that it can be used by researchers and also customizable to their requirement rather than procuring a new one for different applications.
5. A typical flowmeter has a casing, transducer and transmitter. Casing is to ensure leak proof operation thereby avoiding any measurement error. Transducer senses the fluid passing through them and converted through transmitter into raw signal. In this project, the data is processed using Arduino and displayed through LCD display.

Bill of Materials

1. Component of 3-d printer Casing:

• Lower casing with integrated input and output tube
• Blade rotor
• Bearing carrying plate
• Magnet mounted plate
• top casing cover
• Bearing (outer dia 30, inner dia 10, thickness 10) (in mm)
• 2XM8 bolt and nut

2. Electrical Component

• Auduino Board
• Couple of breadboard
• Hall effect sensor
• LCD display
• Electrical wires

• All parts required for the assembly of the apparatus available at https://www.youmagine.com/designs/flow-meter

Tools needed for fabrication of flowmeter

1. MOST Delta RepRap or similar RepRap 3-D printer

Skills and Knowledge Necessary to edit design

• 3D Modelling software - FreeCAD
• CURA(Matter control software)
• Arduino programming

Arduino and hall effect sensor

Arduino is a microcontroller ,for projects requiring less computational memory this is a very useful device. In our project we have used arduino to compute flow . For detecting flow we are using hall effect sensor. Hall effect sensor works on the principle o magnetc field . It has a thin strip of metal which is given a potental difference across it. Whenever there is magnetic field, the metal strip deflects causing a change in output voltage. the change in voltage output is detected as pulse on arduino. Unlike othertransducer hall effect has an advantage , it detects static magnetic field aswell  ; while other sensor detects change in magnetic field. Over perod of time hall effect sensor has found its uses increasingly in varied applivcation viz as an encoder ,proximity sensor, rpm, limit switch . Here in our project Hall effect sensor works as a encoder. It has three terminal two for supply and the third one is for signal. Here in our flowmeter there is a small button magnet mounted on top of the disk which rotates with the bearing .The magnet is detected by hall effect sensor whenever it crosses the near field. This acts as digital input on arduino . The no of pulses is used to compute the rate of flow and total flow as well. Computng the no of pulses within a sampling period gives the rate of flow. For displaying flow we are using 16x2 LCD display, mounted on bread board. The arrangement is as shown in the figure. We are using pin no 10 of arduino for hall effect signal

Ardunio code

Detection of magnet by hall effect sensor is used as count in the program, the program sums this count with the previous counts stored in a variable ; multiplying with a caliberation factor gives the flow. This flow is displayed on the LCD. Arduino code is as follows

include <LiquidCrystal.h>
const int  buttonPin = 10 ;    // the pin that the pushbutton is attached to
const int ledPin = 13;       // the pin that the LED is attached to
const int rs = 8, en = 9, d4 = 4, d5 = 5, d6 = 6, d7 = 7;
LiquidCrystal lcd(rs, en, d4, d5, d6, d7);
// Variables will change:
int buttonPushCounter = 0;   
int buttonState = 0;        
int lastButtonState = 0;   
int Calc;
int Calc1;
int  Calc_lst=0;
void setup() {
 // initialize the button pin as a input:
 pinMode(ledPin, OUTPUT);
 // initialize serial communication:
 Serial.begin(9600);
lcd.begin(16, 2);
 }

void loop() {
 buttonState = digitalRead(buttonPin);
 // compare the buttonState to its previous state
 if (buttonState != lastButtonState) {
   // if the state has changed, increment the counter
   if (buttonState == HIGH) {
     // if the current state is HIGH then the button went from off to on:
     buttonPushCounter++;
     Serial.println("on");
     Serial.print("number of button pushes: ");
     Serial.println(buttonPushCounter);
   } else {
     // if the current state is LOW then the button went from on to off:
     Serial.println("off");
   }
  
   delay(5);
 }
 lastButtonState = buttonState;
if (buttonPushCounter  == 0) {
   digitalWrite(ledPin, HIGH);
 } else {
   digitalWrite(ledPin, LOW);
 }
 lcd.clear();
 lcd.setCursor(0,0);
  Calc= buttonPushCounter*50;
 lcd.print("Total counts ");
lcd.print(buttonPushCounter);
lcd.setCursor(0,1);
  lcd.print("Total flow ");
  lcd.print(Calc);
  lcd.print( " mL");
 delay(2);
}

Technical Specifications and Assembly Instructions

1. Download all the .stl files from the link mentioned above.
2. Print all the parts keeping equal scale(x=100% y=100% z=100%) on CURA.
3. Trim off any extruding flash obstructing assembly.
4. Take the lower casing and on it place the blade rotor, the grove part of the blade should go on the casing.

   

   
5. Smaller hole is designed and hence material has to be scraped form the inner surface of the printed part. Ensure sealing of bearing for any leak. Take the bearing assembled and bolt it to the lower casing and on it place the blade rotor, the grove part of the blade should go on the casing.

   
6. Place the magnet mounted plate on the other side of bearing. Place the covering on it top and bolt the whole assembly with M8 bolt and nut

   
7. The print time for the complete assembly must be around 12-14 hours with 30% Infill.

1. Hall effect sensor was mounted on the casing taking care the diameter of the magnet plate.
2. Circuit Connection:
   1. Hall effect sensor has 3 wires, the two outer for voltage input and the middle wire gives the signal which is straight away given to Arduino.
   2. The ports of LCD and aurduino board are connected as shown in the picture.
   3. Battery was connected to Arduino board

1. Demonstration video as shown

3D printed Flowmeter demonstration video
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Calibration

1. The component were assembled and was feed into a tap as shown in demonstration. Time was also being recorded. water was allowed to be flow and collected in a bucket. After one minute the water calculated was recorded in litres. The total pulse was noted from LCD display.
2. Each pulse reading could consequently be calculated both for litre discharge per min and each pulse computes the flow in each count
3. For our case, each pulse was 50 ml of water.

Cost savings

1. The estimated cost of PLA material is approximately $7 for the basic PLA filament.
2. Commercial equivalent costs approximately $50-150. Check the commercial version here -> [1]
3. Savings of $90 is easily possible for our apparatus.

Improvement and adaptability

1. The no blades of the fan can be modified according to the type of liquid used to be detected by flow meter. Since flow meter with higher mass will require lesser no of blades. And the flowmeter with lower mass will require more no of blades for accuracy
2. For better precision the fan shape can be changed to the one shown in the figure . As its blade has curve assisting flow in a particular . Thus reducing error of missing counts while computing flow

Future Works

1. Improvement in design and customizer feature.
2. Tolerances of 3d part could be defined for easy assembly.
3. Use of cheaper borad or customized board for cost reduction.
4. Cabinet design for electrical.
5. Designing and developing similar project for better utilization of electrical component and increasing features.