MINI STEAM GENERATOR

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 09 Issue: 11 | Nov 2022 www.irjet.net p-ISSN: 2395-0072
© 2022, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page 51
MINI STEAM GENERATOR
1 Dr. Jonny Carmona Reyes, 2 Cruz Norberto González Morales, 3 Luis Ángel Juárez Cerón,
1,2,3, Universidad Tecnológica de Tlaxcala, El Carmen Xalpatlahuaya, Huamantla, Tlaxcala, México, 90500
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Abstract - This document presents the invasion of a mini
steam generator that will be programmed by means of
pressure, temperature and water level sensors. The mini
generator will be portable, thus innovating the sizesince most
boilers or industrial steam generators are large, and heavy. It
has a digital controller that will controlthesensorsandwill be
shown in a digital screen. It is required an appropriatelevel of
water so that the boiler continuously generates steam. The
temperature that the water must contain when filling the
boiler and the generator will reduce accidents due to poor
control of temperature, level and pressure.
Key Words: Temperature, pressure, programming,
generator, sensors.
1. INTRODUCTION
Preventive maintenance is the act of performing regularly
scheduledmaintenanceactivitiestohelppreventunexpected
failures in the future. In other words, it's about fixing things
before they break. The benefits that maintenance gives us is
the increase in the life of the assets, reduce maintenance,
boost activity, reduce downtime in addition to reducing
failures, preventing catastrophesandsaving economy.In the
industry, the figure for a steam generator to explode is
35949.0% due to poor maintenance and supervision of the
level. (Machines, 2019).
The problem that regularly arises in steam generators is the
poor supervision of water level and its installation, this
causes explosions and therefore human and material losses.
For this reason, it is proposed the implementation of
temperature sensors, water level sensors, and pressure
sensors besides this, they will be programedwithArduino in
order to reduce the number of accidents due to poor
supervision of steam generator.
The steam generator itself is a closed vessel that generates
water vapor at pressures higher than atmospheric. The
temperature of the liquid increases until it reaches the
vaporization temperature and remains constant while the
liquid becomes vapor, once the boiling temperature is
reached, the operating pressure continues the heat supply
and vaporization begins without temperaturevariation.The
steam generator is made with a stainless steel tubularwitha
height of 50cm, a diameter of 33cm, an electrical resistance
for heating, as well as a layer of fiberglass for protection, a
sheet cap, with temperature and pressure meters.
2. METHODOLOGY
For the development of this project, a container was first
manufactured with a 316 stainless steel schedule 20 tube
with a length of 500mm and a diameter of 101.6mm.
Therefore, the container has 2 lids on both sides with a plate
of the same material with a thickness of 3mm, for that 316
welding of 1/8 in diameter was applied, which also allows
the correct fusion of the materials, Figure 1.
Fig- 1 Container
3 3/8 connections were adopted, and 2 were placed in the
lower part of the container for the water supply and to place
the temperature sensors, likewise, 1 was installed in the
upper part for the adaptation of the pressure sensor.
Therefore, 2 thermowells were placed for the adaptation of
type K thermocouples in two different areas of the container
to detect the temperature of the liquid, 2 stainless steel
nipples 1, ¼” were also placed where they will be set the
water level sensors to control the levelfromtheinside.Inany
case, all these variables will becontrolledsemi-automatically
by the ATMEGA 328P microcontroller, Figure 2.

Fig- 2 Placement of thermowells.
Likewise, for the steam outlet, an outlet was adapted at the
top of the container. In the same way, it will be controlled by
a metal ball valve that allows manual control of the steam
outlet. However, it also has a check valve brass relief that
opens at 1.23MPa for safety in case the internal pressure of
the container is exceeded, Figure 3.
Fig- 3 Placement of relief valve.
Later tests were carried out to verify leaks inside the steam
generator since there are parts that were welded. For this
reason, it was decided to test the container in weldingjoints,
so it was subjected to compressed air tests in addition to a
water test was carried out to rule out leaks between the
welded pieces, in such a way that theresultwasnegative and
no leak was found, later all the sensors were placed in their
respective places to carry out said tests to verify that it did
not exist any leak once the sensors are placed in their
respective place.
In this way, to generate heat in the container, a 65W/in low-
density cartridge-type tubular resistance with a diameter of
6.6mm and a length of 255mm was installed with a 120VAC
power supply for 180°C (350 °F), Figure 4.
Fig-4 Placement of resistance.
It should be considered that it is very important to measure
the temperature of the steam generator, which is why2type
K thermocouples were used with their respective MAX6675
transmitter to make temperature measurements in a wide
range from 0° to 1024°C so that their supply is from 3.3 - 5V,
its working current is 50mA, the temperature rangeisfrom-
200°C to 1024°C and its temperature resolution is 0.25°C;
therefore, the 2 thermocoupleswill beprogrammedwiththe
ATMEGA 328P microcontroller, Figure 5 and 6.
Fig- 6 Type K thermocouple and MAX 6675 module.
Fig- 5 Rod-type thermometer

To measure the pressure, an analog sensor HK3022 was
used, which works at a range of 0 to 0.5MPa for constant
pressure systems such as water, air, and oil. The sensor
output has an analog voltage that varies linearly from 0.5V
equivalent to 0MPa and 4.0V equivalent to 0.8MPa, for this
reason, its analog outputs are compatible with the analog
inputs (ADC) of the ATMEGA 328P microcontroller,Figure 7.
Figure 7 Analog pressure sensor.
In this way, to measure the water level frominsidethesteam
generator, 2 stainless steel angle level sensors wereused for
the filling and emptying operation, is based on a magnetic
Reed Switch type switch that is hermetically sealed inside
the stem of our sensor and activated by moving the foam
float that contains a permanent magnet so its voltage range
is 0 – 250V, Max. 0.5 - 120VAC, Open circuit resistance 100
MO, Closed-circuit resistance 0.4 O, Power 10W, Operating
temperature -30° ~ 125° C, Thread diameter 28 mm, Nut
diameter 1/8´NPT, Figure 8.
Fig- 8 Switch-type water level sensor.
For filling the steam generator with water, a 12 V DC Mini
electric water pump was used, with a power of 6W,
operating current 0.5-0.7A, Traffic:1300mL/min100ml,Lift
1.5m, life up to 2500H, water temperature is 5-40, outlet
diameter: 6.72mm, size 98 x 35mm, so 6 meters of 6.72mm
transparent hose was used to fill thesteamgenerator,Figure
9 and 10.
Fig- 9 12V water pump.
Fig- 10 Hose
Once all the sensors were placed in their respective places,
tests were carried out with the temperature sensors so that
the steam generator was filled with water, later the
resistance was connected to heat the water and be able to
carry out the temperature tests and verify from ATMEGA
328P, so the result was positive since the 2 thermocouples
marked their temperature, Figure 11.
Fig- 11 Test
In the same way, pressure tests were carried out, which
were done with hot water, allowingit toreacha temperature
of 90°C to generate steam pressure, so the pressure sensor
marked the data in ATMEGA 328P so that a second test
where the steam generator was emptiedandcompressedair
was put inside the container so that the 2 forms the sensor
marked its pressure.
To better understand the operation of the process, the
following flow chart of the pressure sensor is shown (Figure
12) in which the functionality of the pressure sensor is
represented, said sensor will collect the data of the pressure
that is inside the generator, a once the sensor checks the

measurement, the data will be sent to the ATMEGA 328P
serial monitor where the data will be displayed. Said
measurements will be repeated during the time that the
steam generator is in operation.
Fig- 12 Diagram of the operation of the pressure sensor.
The following diagram of the operation of the level sensor
will be explained (Figure 13), its main function is to activate
and deactivate the pump that supplies water to the
generator. The aforementioned sensorhasa similarfunction
to a switch, therefore, when the container is at its maximum
water level, the sensor will maintain the function of an NC
switch, consequently, due to the production of steam, the
water level will decrease. and the sensor will take the
function of a NA switch.
Fig- 13 Level sensor flow chart
So that the slack diagram of the temperature sensor will be
explained (Figure 14), which represents theoperationofthe
thermocouple. Its purpose is to keep the temperature in
ATMEGA 328P monitored so that it will avoid any accidents
and will allow it not to exceed the temperature at which it
should be maintained.
Figure 14 Temperature sensor flowchart
3. CONCLUSIONS
Based on this research, the efficiency of the steam generator
depends on its design. The sensors and the water pump that
feeds the generator were correctly installed. Through
ATMEGA328P they will have pressure, temperature and
level readings.
Filling tests were performed on the generator and it was
observed that the level switches correctly deactivate the
generator feed pump.
With the help of a display of the ATMEGA328P
microcontroller, the readings are displayed that allow us to
keep abreast of the internal temperature of thecontainer,so
that the water that enters the boiler through the pump will
have a temperature of 40 ° C by means of the feed water
preheating system, to have a constant evaporation. It is
worth mentioning that the safety valve never opened due to
some excess internal pressure. Thus, verifying that the
pressure and temperature indicators implemented fulfilled
their function. Some possible causes of failurewouldbethat
if you do not have water at a minimum temperature of 40°C,
a thermal shock can be caused, and the resistance would
have a lower quality of life. If the steam generatorreaches an
overpressure, it can generate an explosion, and if the pump
fails, it would run out of liquid and the generator would
explode.
It is important to look for an ideal type of water that does
not affect or damage the container because when the water
gets very hot, it can generate scale that sticks to the water

level sensors. Finally, the generator must contain a foil
coating for greater personal safety.
REFERENCES
E. J. Alzate Rodríguez, J. W. Montes Ocampo, y C. A. Silva
Ortega, «Medición de temperatura: sensores
termoeléctricos», Sci. tech, vol. 1, n.º 34, may 2007.
Sepúlveda, D. L., & Ramírez, J. (2011). Condiciones de
seguridad en calderas de vapor de empresas afiliadas a una
administradora de riesgos profesionalesenAntioquia,2009.
Revista Facultad Nacional de Salud Pública, 29(2), 145-152.
Gonzalez, M. A. (1999). Análisis de riesgos del tratamiento
del agua para calderas. Plaza y Valdes.
Varetto, R. H. (2012). Conducción de generadores de vapor.
TECNIBOOK EDICIONES.

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