The 8 Best Flow Meters of 2021

Abstract 

The objective of this project is to learn how to design and produce a flow meter in a laboratory as well as carrying out an experiment to determine how the equipment operates. The paper outlines the function of the flow meter as an instrument that is used to evaluate the flow rate of a liquid. There are various types of flow meter, classified according to their nature of operation and their functionality. The project actively engages students who are starting the project by assembling the electronic component of the flow meter. Thereafter, the students, with assistance of the laboratory technicians, embark on the process of assembling the mechanical part of the flow meter. This process involves that application of heavy mechanical equipment, such as HURCO, Lathe, CNC deford, and Milling machine. The experiment is carried to determine the relationship between the output voltage and the flow rate, as well as between the rotational velocity and the flow rate. In both cases, the finds reveal that there is a direct proportionality between the respective variables. 

Introduction 

A flow meter is an instrument that used to measure the volumetric or mass flow rate of a gas or a liquid passing through a given point. The amount of a fluid at a particular time or the stream rate passing a given point through a pipe can be measured by conducting a flow meter experiment. The measuring process is diverse and each project or experiment has its engineering requirements and constraints. Different names, such as flow indicator, flow gauge, and liquid meter among others are used to refer to the flow meter, and a given name depends on the a particular industry where the instrument and the technique is applied ( Walpole, Myers, Myers, & Ye, 2014, 87). However, the main function and purpose of the equipment remains the same. For industrial applications, precise calculations of quantity are required and these can be obtained using precision flow meters that can provide accurate monitoring and flow control of a given liquid. 

The quantification mechanism of the flow meter is done by allowing liquid to pass through a small wheel located between the input and output of the flow meter that is opposing the liquid. The interaction of the liquid and the wheel generated some force that causes the wheel to rotate at a speed proportional to the pressure developed by the liquid flowing liquid. A circuit that has a sensor that counts the numbers of rotations per second usually connects the flow meter. As a result, the volume of the liquid is evaluated through determination of the number of rotations. 

The aim of this experiment is to learn how to design and produce a flow meter in a laboratory and the way the equipment operates. 

Theory 

The presence of the fluid that moves through the input section of the flow meter moves the wheel making the electronic circuit to count the quantity of the fluid that is flowing. This process continues until fluid is moved through the output and the wheel stops in a particular time. Each type of fluid flows with is unique properties depending on the medium it is moving, its viscosity, and temperature among other factors (Tokaty, 1994, 126). The pressure of a given fluid changes with varying velocity of the fluid. If a hindrance is put in the path taken by fluid, there will be an increase in the velocity (Chattopadhyay, 2006, 23). Various devices and technique such as flow nozzles, orifice plates, Roatameters, and Venturi tubes among others are used in this field as differential pressures flowmeters. These devices and techniques operate by reducing the area of flow, increasing the speed of flow of a particular fluid (Mohanty, 1994, 496). 

One special method that applies the Faraday’s law of electromagnetic induction is the latest and most advanced method of measuring the stream flow (Durgaiah, 2002, 237). This technique operates in a liquid, which is a good conductor of electricity and the flow pie that is non- conductive. Hence, this technique is usually used in measuring the flow rate of water in various experiments. 

As a result, the calculations of the output voltage for the flow meter with a specific flow rate can be evaluated as indicated below: 

Given 

V out = output voltage 

f = frequency 

Vcc = Input voltage (voltage from the source) = 9V 

C = capacitance = 1.0×10^ -8 F 

R = Resistance = 1.0×10^ 5 Ohms 

L = Length = 2.6 mm 

H = Height = 2.32 mm 

W = Width = 0.34 mm 

D = the larger diameter = 11.8 mm 

d = small diameter = 6.2 mm 

Π = Pie = 22/7 = 3.142 

Number of buckets used = eight (8) 

Flow rate ranging between 0 and 20 ml/s 

Therefore, 

V out = Vcc× F×R×C 

Volume = π(0.5D) 2 – π(0.5d) 2 H – 8(W×L×H) 

F = 2(Flow rate/Volume) 

Rotational Velocity = (Flow rate/ volume) 60 

Risk Management 

There is risk of damaging one’s eye when cutting plastic materials using pillar drill. One is supposed to handle the pillar machine with utmost caution and ensure that safety equipment such as goggles are put on and all instructions are followed. The pillar machine must be firmly bolted to the bench to ensure that it is stable to provide a firm anchorage for safe drilling of large pieces of materials. Nails, hammer, and N4 tap should be used with caution to avoid smashing one’s fingers and hands. Caution must be exercised while using lathe machine to avoid hurting one’s eyes and hands. 

Various other general safety measures must be adhered to during the project. Laboratory coat must always be worn while in the workshop to ensure safety for the participants, for instance it protects one from burns in case of fire. Special types of gloves, such a nitrile must be worn while handling the laboratory equipment. These gloves safeguards one from being affected by the electronic equipment, such electric shocks (Merges, Menell, & Lemley, 2015, 64). Because of the nature of the machines being used for the experiment, it is advisable for students to wear strong boots to protect their feet being hit by heavy metals in the laboratory. All efforts and precautionary measures must be undertaken to safeguard individuals taking part in the project from being affected with sparks, electrical shocks, fumes from the flying wood and plastic as well as burns from the soldering activities. 

Method and materials 

Electronic part 

Different components are required for building the electronic circuit for the experiment 

The following materials were availed for the electronic section of the experiment: 

7 Resistors 

2 Capacitors 

LED 

Green board 

Black and red wires 

Optical sensor 

Battery clip black and red wires 

Operational amplifier 

Battery 

Potentiometer 

Procedure 

The components were arranged in the green board accordingly, where they were soldered and the overload iron cut. The voltage was measured from 0V to 9V and the current kept at 0.04A. The LED was checked to confirm if it was working. Thereafter, the optical sensor of in the opposite side of other components was soldered in the green board. This soldering completed the electronic part of the circuit. 

Mechanical Part 

Various mechanical instruments to be used in this experiment include: 

Pillar drill 

Vice machine 

Height gauge 

Hammer 

Nails 

N4 tap 

HURCO machine 

Lathe machine 

CNC deford machine 

Milling machine 

The pillar drill is used to cut plastic and any other materials for the experiment. The vice machine is used to hold plastic and metallic equipment together during the experiment. Heights readings on different equipment is measured by the height gauge machine. The lathe machine is used to cut metals as well as make various shapes of materials that may be required in the experiment. The CNC denford machine is designed to multitask, and it is used by typing the necessary data into it. The milling machine is used to make holes on the plastic materials. Once all the machines have been used accordingly to produce the necessary mechanical parts, the flow meter was assembled through the combined effort of students as shown by the figures below: 

Data and Results 

Volume = π(0.5D) 2 – π(0.5d) 2 H – 8(W×L×H) 

Volume = π(0.5×11.8)^ 2 – 2.32×π(0.5×6.2)^ 2 – 8(0.34×2.6×2.32) = 22.9129mm^ 3 

V out = Vcc × F×R×C 

But, F = 2(Flow rate/Volume) 

Therefore, 

V out = Vcc ×2(Flow rate/Volume) ×R×C 

Table 1 of the measurement recorded during the project 

Flow rate  Ml/s	Volume  Mm^3	Frequency  Hz	Rotational velocity  r/m	Voltage  ( V)
0	167.26	0.00	0.00	0.00
1.00	167.26	11.96	358.72	0.11
2.00	167.26	23.91	717.45	0.22
3.00	167.26	35.87	1076.17	0.32
4.00	167.26	47.83	1434.89	0.43
5.00	167.26	59.79	1793.61	0.54
6.00	167.26	71.74	2152.34	0.65
7.00	167.26	83.70	2511.06	0.75
8.00	167.26	95.66	2869.78	0.86
9.00	167.26	107.62	3228.51	0.97
10.00	167.26	119.57	358.23	1.08
11.00	167.26	131.53	3945.95	1.18
12.00	167.26	143.49	4304.68	1.29
13.00	167.26	155.45	4663.40	1.40
14.00	167.26	167.40	5022.12	1.51
15.00	167.26	179.36	5380.84	1.61
16.00	167.26	191.32	5739.57	1.72
17.00	167.26	203.28	6098.29	1.83
18.00	167.26	215.23	6457.01	1.94
19.00	167.26	227.19	6815.74	2.04
20.00	167.26	239.15	7174.46	2.15

Table 2 of the details of the project 

	mm	Radius
Outer Diameter	11.90	5.95
Inner diameter	6.29	3.15
Impellor thickness	3.22
Plate thickness	0.67
Blade thickness	0.62
Number of pockets	8
PI	3.141592654
Depth of pocket	2.55
Length of each blade	2.805
	mm^3
Whole impellor Cylinder	358.1
Inner Boss Volume	79.24
Rear Plate Volume	74.52
Volume Of Each Blade	5.60
Total Volume Of Blades	44.80
All 8 total Pocket Volume (mm^3)	159.6
Volume Of One Pocket (mm^3)	19.9468
Volume of 8 pockets (ml)	0.1596
Volume of 8 pockets (l)	0.00015957
Flow Rate (ml/s)	20
Revolution per second (RPS)	125.3331
Rounds per minute (RPM)	7519.9856
Frequency (Hz)	250.6662
Voltage (Vcc)	9	V
voltage output	0.2256
R5	100000	Ohms
C2	0.0000000010	Farads

Table 3 Voltage Output Vs Flow rate 

Flow rate (ml/s)	Voltage out (v)
0	0.0000
1	0.0113
2	0.0226
3	0.0339
4	0.0451
5	0.0564
6	0.0677
7	0.0790
8	0.0903
9	0.1016
10	0.1128
11	0.1241
12	0.1354
13	0.1466
14	0.1579
15	0.1692
16	0.1805
17	0.1918
18	0.203
19	0.2143
20	0.2256

Graph 1 of Voltage Output Vs Flow rate 

Table 3 of the flow rate vs rotational velocity per second 

Volumetric Flow Rates (ml/s)	Rounds per second (RPS)
0	0
1	6.266654683
2	12.53330937
3	18.79996405
4	25.06661873
5	31.33327342
6	37.5999281
7	43.86658278
8	50.13323747
9	56.39989215
10	62.66654683
11	68.93320152
12	75.1998562
13	81.46651088
14	87.73316557
15	93.99982025
16	100.2664749
17	106.5331296
18	112.7997843
19	119.066439
20	125.3330937

Graph 2 showing the relationship between the flow rate and the rotational velocity 

Discussion and Analysis of the Results 

Graph 1 indicates that the output voltage and the flow rate are directly proportional. This relationship means that an increase in the voltage increases that voltage in the circuit. Graph 2 shows similar relationship where rotational velocity is directly proportional to the flow rate. A small increase in flow rate generate significant increase in the rotational velocity. For instance, increasing the rotational velocity from 3 ml/s to 4 ml/s increases the rotational velocity from 1076.17 r/m to 1434.89 r/m. 

From the test conducted on the flow meter, it was found that the output voltage was 0.32V and the flow rare as 320 ml per minute, equivalent to 5.333ml/s. 

From, 

V out = Vcc ×2(Flow rate/Volume) ×R×C 

0.32 = 9×2 × (Flow rate/22.91 × 10^-3) × 1.0 × 10^5 × 1.0 × 10^-8 

Flow rate = 0.407ml/s 

Error of the percentage = ((actual – expected)/actual) × 100 

Error percentage = ((5.12 – 0.4060/5.12) × 100) = 92.05 % 

Conclusion 

In conclusion, the objective of the project was achieved as both the mechanical and the electric parts of the flow meter were successfully assembled using the available materials and equipment. The project and experiment was elaborated in an appropriate and comprehensive way that could be understood by students. Besides, the flow rate was evaluated through the application of the flow meter, which students assembled. The project also established the direct relationship between the rotational velocity and the flow rate was well as the direct relationship between the output voltage and the flow rate of the flow meter. This relationship signifies that an increase in the flow rate increases both the output voltage as well as the rotational velocity. However, the experiment recorded a substantial percentage error of 92.05%. This big error indicates the presence of a much lower flow rate than the actual flow rate. 

References 

Chattopadhyay, P. (2006).  Flowmeters and flow measurement . New Delhi, Asian Books. 

Durgaiah, D. R. (2002).  Fluid mechanics and machinery . New Delhi, New Age International. 

Merges, R. P., Menell, P. S., & Lemley, M. A. (2015).  Intellectual property and the new technological age: 2015 case and statutory supplement . New York, NY, Wolters Kluwer Law & Bus. 

Mohanty, A. K. (1994).  Fluid mechanics . New Delhi, Prentice-Hall of India. 

Tokaty, G. A. (1994).  A history and philosophy of fluid mechanics . Retrieved from: https://www.overdrive.com/search?q=A46AE7DB-3C3E-4D53-A1F1-56BF9BC8056D. 

Walpole, R. E., Myers, R. H., Myers, S. L., & Ye, K. (2014).  Probability and statistics for engineers and scientists . Retrieved from: https://www.dawsonera.com/guard/protected/dawson.jsp?name=https://shib-idp.ucl.ac.uk/shibboleth&dest=http://www.dawsonera.com/depp/reader/protected/external/Abstract.