An oxide capacitor consisting of BaTiO3 and an oxide is studied as a new
type CO2 gas sensor based on capacitance change. Sensitivity to CO2, as
well as the optimum operating temperature, was strongly dependent on the
particular oxide mixed with BaTiO3.
Among the elements investigated in this study, CuO–BaTiO3 exhibited the
highest sensitivity to CO2. In particular, the CuO–BaTiO3 mixed oxide at
the equimolar composition is highly sensitive to CO2. The optimum
operating temperature and frequency for CuO–BaTiO3 are 729 K and 100 Hz,
respectively, and the 80% response time to 2% CO2 is within 25 s. The
equimolar mixture of CuO and BaTiO3 can measure the CO2 concentration
from 100 to 60 000 ppm. Carbonation of oxide seems to play a key role
for the detection of CO2 on these mixed oxide capacitors.
The optimum operating temperature of these mixed oxide capacitors for
CO2 detection, therefore, correlates with the decomposition temperature
of the carbonate corresponding to the oxide mixed with BaTiO3. The
capacitance increase of CuO–BaTiO3 upon exposure to CO2 seems to result
from the elevated height of the potential barrier at the grain boundary
between CuO and BaTiO3. Carbonation of CuO in the element seems to bring
about the elevation in the height of the potential barrier.
ISweek（http://www.isweek.com/）- Industry sourcing & Wholesale industrial products
2016年6月2日星期四
Global Fibre Optics Sensors Market to Grow Steadily at a CAGR of About 9% During 2016-2020
Technavios market research analyst predicts the global fiber optic sensors market to grow steadily at a CAGR of about 9% during the
forecast period. The fiber optic sensors capability of a higher
tolerance for high temperatures is expected to drive the demand for
these sensors in applications that has extreme environmental conditions
and where electrical sensors fail to function properly, such as the oil
and gas, and manufacturing sector.
Increased exploration of unconventional resources is another major factor expected to increase the revenues of the fiber optic sensors market during the forecast period. Fiber optic sensors are integrated into equipment used during the drilling and exploration stages. The increase in consumption of oil and gas and the decline in the production of conventional oil reserves has forced vendors and governments to indulge in exploration and drilling activities, therefore, leading to greater demand for fiber optic sensors in this industry.
Product segmentation and analysis of the fiber optic sensors market
- Intrinsic fiber optic sensors
- Extrinsic fiber optic sensors
The intrinsic sensors segment dominated the market during 2015, with a market share of above 93%. Intrinsic sensors are used to measure physical properties such as strain, pressure, and temperature. The main reason behind the dominance of intrinsic sensors is the early adoption of these sensors in oil and gas industry.
Segmentation by end-user and analysis of the fiber optic sensors market
- Oil and gas
- Manufacturing
- Infrastructure
- Security
- Others
Oil and gas accounted for nearly 31% of the market share during 2015. The high demand for equipment used for exploration and drilling activities and the ability of fiber optic sensors to measure temperatures and strain at different locations through a single fiber using multiplexing technology has been driving the growth of this segment.
Geographical segmentation and analysis of the fiber optic sensors market
- Americas
- APAC
- EMEA
The Americas accounted for almost 42% of the market share during 2015 and is expected to grow at a CAGR of close to 10% during the forecast period. The high adoption rate of fiber optic sensors in the manufacturing industry and the availability of huge reserves resulting in increased exploration and drilling activities are the primary drivers for the market growth in this region.
Key questions answered in the report
- What will the market size and the growth rate be in 2020?
- What are the key factors driving the global fiber optic sensors market?
- What are the key market trends impacting the growth of the global fiber optic sensors market?
- What are the challenges to market growth?
- Who are the key vendors in the global fiber optic sensors market?
- What are the market opportunities and threats faced by the vendors in the global fiber optic sensors market?
- Trending factors influencing the market shares of the Americas, APAC, and EMEA.
- What are the key outcomes of the five forces analysis of the global fiber optic sensors market?
ISweek（http://www.isweek.com/）- Industry sourcing & Wholesale industrial products
Increased exploration of unconventional resources is another major factor expected to increase the revenues of the fiber optic sensors market during the forecast period. Fiber optic sensors are integrated into equipment used during the drilling and exploration stages. The increase in consumption of oil and gas and the decline in the production of conventional oil reserves has forced vendors and governments to indulge in exploration and drilling activities, therefore, leading to greater demand for fiber optic sensors in this industry.
Product segmentation and analysis of the fiber optic sensors market
- Intrinsic fiber optic sensors
- Extrinsic fiber optic sensors
The intrinsic sensors segment dominated the market during 2015, with a market share of above 93%. Intrinsic sensors are used to measure physical properties such as strain, pressure, and temperature. The main reason behind the dominance of intrinsic sensors is the early adoption of these sensors in oil and gas industry.
Segmentation by end-user and analysis of the fiber optic sensors market
- Oil and gas
- Manufacturing
- Infrastructure
- Security
- Others
Oil and gas accounted for nearly 31% of the market share during 2015. The high demand for equipment used for exploration and drilling activities and the ability of fiber optic sensors to measure temperatures and strain at different locations through a single fiber using multiplexing technology has been driving the growth of this segment.
Geographical segmentation and analysis of the fiber optic sensors market
- Americas
- APAC
- EMEA
The Americas accounted for almost 42% of the market share during 2015 and is expected to grow at a CAGR of close to 10% during the forecast period. The high adoption rate of fiber optic sensors in the manufacturing industry and the availability of huge reserves resulting in increased exploration and drilling activities are the primary drivers for the market growth in this region.
Key questions answered in the report
- What will the market size and the growth rate be in 2020?
- What are the key factors driving the global fiber optic sensors market?
- What are the key market trends impacting the growth of the global fiber optic sensors market?
- What are the challenges to market growth?
- Who are the key vendors in the global fiber optic sensors market?
- What are the market opportunities and threats faced by the vendors in the global fiber optic sensors market?
- Trending factors influencing the market shares of the Americas, APAC, and EMEA.
- What are the key outcomes of the five forces analysis of the global fiber optic sensors market?
ISweek（http://www.isweek.com/）- Industry sourcing & Wholesale industrial products
Optic Fiber Methane Gas Sensor Based on Tunable Diode Laser Absorption Spectroscopy
Tunable diode laser absorption spectroscopy (TDLAS) is a widely used
technique in measuring the concentration of trace gas due to its high
sensitivity, high selectivity, and fast time response.
The fluctuations of temperature in the gas cell can cause the characteristics of the absorption spectra to change in the TDLAS methane sensing system. The three absorption lines in the R(3) transitions of 2v3 band of methane at 1653.72 nm have been studied, and the influence of the temperature fluctuations on the spectral absorption coefficient and the amplitude of second harmonic is analyzed.
A simple piece of equipment with temperature acquisition devices is developed for measuring methane gas concentration, temperature signals are obtained for eliminating the impact of temperature fluctuations.
Using calibration coefficient, the amplitude of second harmonic is transformed into standard signal at reference temperature in order to restrain the influence of temperature fluctuations. The results show that this optic fiber methane gas sensor using tunable diode laser absorption spectroscopy can restrains the influence of temperature fluctuations and improves detection accuracy effectively.
ISweek（http://www.isweek.com/）- Industry sourcing & Wholesale industrial products
The fluctuations of temperature in the gas cell can cause the characteristics of the absorption spectra to change in the TDLAS methane sensing system. The three absorption lines in the R(3) transitions of 2v3 band of methane at 1653.72 nm have been studied, and the influence of the temperature fluctuations on the spectral absorption coefficient and the amplitude of second harmonic is analyzed.
A simple piece of equipment with temperature acquisition devices is developed for measuring methane gas concentration, temperature signals are obtained for eliminating the impact of temperature fluctuations.
Using calibration coefficient, the amplitude of second harmonic is transformed into standard signal at reference temperature in order to restrain the influence of temperature fluctuations. The results show that this optic fiber methane gas sensor using tunable diode laser absorption spectroscopy can restrains the influence of temperature fluctuations and improves detection accuracy effectively.
ISweek（http://www.isweek.com/）- Industry sourcing & Wholesale industrial products
2016年6月1日星期三
A Virtual EXV Mass Flow Sensor for Applications With Two-Phase Flow Inlet Conditions
In conventional vapor compression systems,
electronic expansion valves (EXVs) are used for refrigerant flow control.
Subcooled refrigerant enters the expansion device and is expanded to the
evaporation pressure while the valve opening is modified to achieve the desired
mass flowrate.
The relationship between the inlet and outlet
conditions, the opening, and the mass flowrate has been extensively studied,
e.g. by Park et al. (2007) and appropriate empirical correlations have been
developed. However, for certain operating conditions (e.g. low refrigerant
charge) or applications that generally have two-phase inlet conditions (e.g.
balancing valves used in a hybrid control scheme as proposed by Kim et al.
(2008)), these correlations are not applicable, since even low inlet vapor
fractions lead to a significant reduction of the valve mass flowrate at a given
opening.
This paper proposes a continuous correlation
that can be used for both two-phase and subcooled valve inlet conditions. The
benefit of the continuity is that there is a smooth transition between
subcooled and two-phase inlet conditions, which is essential for control and
simulation purposes. The new correlation employs the Buckingham-Pi theorem as
proposed by Buckingham (1914). The selected dimensionless Pi-groups describe
opening of the valve, subcooling, inlet and outlet pressures, driving pressure
difference across the valve, inlet density, surface tension, and viscosity.
The data that was used to determine the
coefficients of the correlation was taken on a dedicated valve test stand,
which was sized for the per-circuit capacity of a typical 5-ton R410A heat pump
and a 3-ton R404A large room cooling system. The purpose of these tests was
mainly to map the valves for the low pressure drops, high inlet qualities and
large valve openings that occur when they are used as balancing valves in a
hybrid control approach. Two commercially available valves of different rated
capacity were tested.
Due to the much higher valve capacity for
subcooled inlet conditions, valve openings of less than 5% occurred in that
case. This led to an accuracy of the correlation for these points that is less
than what typically can be found for correlations with subcooled inlet
conditions in the open literature. However, for two-phase flow inlet
conditions, the resulting RMS of 1.0 g/s for the 8-PI correlation is
sufficiently small to use the approach for estimating the refrigerant mass flow
and using the EXV as a virtual mass flow sensor. The limitations of this approach in
practical applications, as well as possible applications in fault detection and
diagnostics are shown for application as balancing valves within a 5-ton R410A
heat pump and a 3-ton R404A large room cooling system.
Methane Sensor for Mars
Methane Sensor for Mars (MSM), on-board Mars Orbiter Mission is a
differential radiometer based on Fabry–Perot Etalon (FPE) filters which
measures column density of methane in the Martian atmosphere.
It is the first FPE sensor ever flown to space. Spectral, spatial and radiometric performances of the sensor were characterized thoroughly during the pre-launch calibration. Geophysical calibration of the sensor was carried out using the data acquired over Sahara desert during Earth Parking Orbit phase.
Retrieval algorithm for MSM, which is based on the linearization of radiative transfer equations, gets simultaneous solutions for CH4 and CO2 concentrations in the Martian atmosphere.
ISweek（http://www.isweek.com/）- Industry sourcing & Wholesale industrial products
It is the first FPE sensor ever flown to space. Spectral, spatial and radiometric performances of the sensor were characterized thoroughly during the pre-launch calibration. Geophysical calibration of the sensor was carried out using the data acquired over Sahara desert during Earth Parking Orbit phase.
Retrieval algorithm for MSM, which is based on the linearization of radiative transfer equations, gets simultaneous solutions for CH4 and CO2 concentrations in the Martian atmosphere.
ISweek（http://www.isweek.com/）- Industry sourcing & Wholesale industrial products
New Optical CO2 Sensor Using ATR Technology from Anton Paar
Carbo 520 Optical from Anton Paar is an inline CO2 sensor that is easily
installed directly inline and in constant contact with the processed
sample. Carbo 520 Optical measures CO2 concentration based on the
spectroscopic approach of Attenuated Total Reflection (ATR), so the only
“motion” in the system is the passing of infrared light through a
crystal. Since the sensor has no moving or mechanical parts, there is no
wear and tear and no disposables are required.
Benefits of the Carbo 520 Optical include:
Minimize your operating costs
• Requires 10 W or less
• Needs no external purging gas or compressed air
• No consumables required
Selective and reliable
• Selective CO2 measurement
• Not influenced by other gases (such as nitrogen, oxygen)
• Color and turbidity are irrelevant to the measurement results
Measure all beverages with a single setup
• Sugar composition or solubility have no influence
• Same measurement method for all kinds of beverages like colas, beers, wines etc.
Fast results anytime anywhere
• Every four seconds
• Full connectivity by fieldbus communication (PROFIBUS, ModBus TCP, PROFINET, EtherNet/IP)
• Classic analog outputs (4-20 mA) and digital-IOs available
Carbo 520 Optical from Anton Paar is a truly “fit-and-forget” system that provides linear, drift-free CO2 readings over the entire measurement range from 0 g/L to 12 g/L– and gives way to a new kind of certainty in CO2 monitoring throughout the beverage production process.
ISweek（http://www.isweek.com/）- Industry sourcing & Wholesale industrial products
Benefits of the Carbo 520 Optical include:
Minimize your operating costs
• Requires 10 W or less
• Needs no external purging gas or compressed air
• No consumables required
Selective and reliable
• Selective CO2 measurement
• Not influenced by other gases (such as nitrogen, oxygen)
• Color and turbidity are irrelevant to the measurement results
Measure all beverages with a single setup
• Sugar composition or solubility have no influence
• Same measurement method for all kinds of beverages like colas, beers, wines etc.
Fast results anytime anywhere
• Every four seconds
• Full connectivity by fieldbus communication (PROFIBUS, ModBus TCP, PROFINET, EtherNet/IP)
• Classic analog outputs (4-20 mA) and digital-IOs available
Carbo 520 Optical from Anton Paar is a truly “fit-and-forget” system that provides linear, drift-free CO2 readings over the entire measurement range from 0 g/L to 12 g/L– and gives way to a new kind of certainty in CO2 monitoring throughout the beverage production process.
ISweek（http://www.isweek.com/）- Industry sourcing & Wholesale industrial products
Are You Having Problems with your Photo-Sensors?
Just as car washes vary from self serve to rollover
to tunnel wash, there are many types of sensors being used to start,
stop, measure length, and control the wash and entry/exit doors.
However, all sensors are not created equal. There are early warning
signs to look for that might indicate a maintenance check-up is in
order.
Are the automatic doors operating properly? Are the nozzles turning on and off as needed? Is soap being dispensed after vehicles exit the wash instead of on time? Does snow and ice cause false signals from the photo-eyes?
If your wash equipment and door systems are not functioning correctly, the photo-eyes that signal the wash line's computer system may not be operating properly. We will examine the most common problems that photo-eyes face in the demanding wash environment and the features that you should consider when selecting sensors for your wash. Afterwards, we will review various types of applications in each type of wash and give some "first-aid" tips for your photo-eye sensors.
How many of you have ever experienced fog in your bays so thick that you couldn't see someone standing 10 feet away? This is a very common problem in locations where cooler temperatures during the winter months combined with hot water put extreme demands on your sensors. Most photo-eyes would fail under these circumstances. To compound this problem, add soap, grease and dirty water and you have the makings for a true disaster.
You know the picture. After a week of snow and ice, the sun finally comes out and the temperature rises to create a nice slushy, mud bath for your car. As cars line up at the wash, the last thing the operator needs is for the equipment to stop working. One single day of non-operation means lost profit that you can never recover.
Keeping your car or truck wash equipment in top-notch condition includes checking and replacing defective photo-eyes. Sensors provide the critical signal to the wash computer. Therefore, it is absolutely necessary they operate properly. As the old saying goes, "junk in, junk out." A photo-eye could mean the marginal difference between profit and loss for your wash.
Common Problems
The number one reason for photo-eye failure is contamination. A car wash is ideally the best testing grounds for a photo-eye because of contamination. Practically, no other industry can compare to the wet, hostile environment of the car wash's dirt, steam, ice, snow, soap, film, grease and everyone's "favorite", fog. If a photo-eye can pass this test, you have a winner.
There are some sensor brands of this caliber on the market. They are able to withstand this type of abuse because they do not use a lens to magnify the light to the receiver eye. Lens-less eyes are usually designed as modulated infrared sensors (see figure 2).
The transmitter LED (light emitting diode) is turned on and off, acting as a pulse of light, invisible to the naked eye. The receiver is calibrated to the same frequency of modulation to accept the transmittal signal.
Just as a lighthouse penetrates the fog to warn an approaching ship of danger, the lens-less photo-eye cuts through fog, steam, dirt and grime to ensure your car wash trouble-free service. Relate the photo-eye made with a lens to a pair of glasses. If you walk into the wash wearing glasses, they immediately become fogged up. You must take the glasses off and clean them. This is a perfect example of the wrong photo-eye to use in a car wash. By removing the photo-eye made with a lens you eliminate the step of continual lens cleaning.
Misalignment is another photo-eye problem common to car wash facilities. In some cases, it is possible to judge visually if the eyes are out of alignment at an angle or askew to one another.
When installing photo-eyes at a distance of eight to twelve feet, it should be possible to pull a string between the two to check positioning. If the viewing angle of the photo-eye is eight degrees or greater, alignment should not be difficult.
The next common reason why so many photo-eyes fail is vibration. Have you ever seen a car or truck wash facility devoid of vibration? With arches turning on and off, and other assorted wash components in constant motion, vibration is certain to occur.
If a photo-eye system is difficult to align when installed, given the amount of on-site vibration, it is highly probable that proper alignment will be difficult to maintain. With a wide opening- angle, or "beam-spread", installation is not only simple, but vibration won't knock the eyes out of alignment.
Mounting plays an important role in photo-eye alignment. In the wash environment, eyes should always be mounted in a through-beam manner (figure 2). Properly mounted eyes promote reliability for the wash over the long haul.
A special word of warning: Do not use reflectors!! (see Pix) In car and truck wash applications, the use of reflectors is a bad idea. Condensation that forms on reflector faces may cause significant problems and they are prone to damage and mischief.
Last, but certainly not least, water leakage can cause photo-eyes to perform intermittently at best, or fail altogether at worst. As water leaks into the housing of the photo-eye, the internal components become damaged and condensation begins to form on the inside of the lens, fogging up glass and plastic lenses alike.
Check the rating on this eye to determine whether it was designed to withstand wash-down or submersion. A rating of IP67 means that a sensor will perform reliably in water. If the photo-eyes in your car or truck wash are not performing up to standards, replace them. Eliminating the problem sensor before it interferes with the performance of the equipment will save you money on those high volume days.
The Right Sensor
Selecting the right sensor for your application can be tricky, and turning the pages of photo sensor catalogs may only add to the confusion.
The components for most infrared systems used in the car wash industry include a transmitter, receiver, amplifier and socket. Don't be tempted to purchase a photo-electric sensor system based on price alone. The cost of installing quality sensor eyes that are made specifically for the car or truck wash is more than justifiable.
As an operator, you're looking for equipment that will perform reliably, day in and day out, with the least amount of maintenance. Remember, your best profit days are when you are managing and the wash is working. Quality eyes will help put you back in the driver's seat of your wash so you can do the important things like servicing and delivering a quality wash.
Light immunity rating, sensing range, strain relief and body style are other features to consider when selecting your sensors; and often the application will help narrow down your choices. For example, if you plan to mount photo-eyes at the entrance to the car or truck wash, a compact body style will simplify installation and service. These sensors should be fully encapsulated, resisting water leakage. The entrance area also subjects the photo-eyes to prolonged exposure to bright sunlight. To avoid intermittent interference, opt for a sensor with a rating of 50,000 LUX or above.
Although operators only need to cover a distance of approximately 10-50 feet, the sensing range of the photo-eye is extremely crucial in carwash applications. Photo-eyes with ranges of 120 feet or more are strongly recommended to ensure that you will have enough power to penetrate the harsh environment caused by dirt, water, soap, fog, etc.
Common applications
Now, let's take a look at some of the most common types of car or truck wash applications.
Self Serve Washes
In self-serve washes, the most common usage is on service-bay automatic doors. Photo-eyes are installed on entrance and exit doors to prevent damage to a car or to the door if the operator closes the door prematurely.
The sensors should be mounted on each side of the door in a through-beam configuration with the transmitter placed on one side and the receiver on the opposite side. (See pix) The amplifier is placed in a watertight enclosure or in the main control panel. As the car comes into or out of the wash, it breaks the infrared beam and signals the door to reverse. Other applications in self-serve washes include automatic entry systems, exit signs, and "unlimited time" self-serve bays.
"Unlimited time" self-serve bays offer extra value to your customers by allowing them plenty of time to clean their vehicles. This may be achieved by installing two photo-electric systems in the bay. One system is used to detect that a vehicle is present in the bay. The second system is used to reset the timer when that customer leaves to prevent the next customer from enjoying a free wash.
Rollover washes
Rollover washes require the car or truck to be driven into the wash and then the machine moves around the vehicle. Photo-eyes are used to position the wash equipment, measure the length of the vehicle and turn the equipment on and off as needed. The entrance and exit doors generally use photo-eyes to signal the PLC or industrial computer that the vehicle has entered or exited the wash.
Are the automatic doors operating properly? Are the nozzles turning on and off as needed? Is soap being dispensed after vehicles exit the wash instead of on time? Does snow and ice cause false signals from the photo-eyes?
If your wash equipment and door systems are not functioning correctly, the photo-eyes that signal the wash line's computer system may not be operating properly. We will examine the most common problems that photo-eyes face in the demanding wash environment and the features that you should consider when selecting sensors for your wash. Afterwards, we will review various types of applications in each type of wash and give some "first-aid" tips for your photo-eye sensors.
How many of you have ever experienced fog in your bays so thick that you couldn't see someone standing 10 feet away? This is a very common problem in locations where cooler temperatures during the winter months combined with hot water put extreme demands on your sensors. Most photo-eyes would fail under these circumstances. To compound this problem, add soap, grease and dirty water and you have the makings for a true disaster.
You know the picture. After a week of snow and ice, the sun finally comes out and the temperature rises to create a nice slushy, mud bath for your car. As cars line up at the wash, the last thing the operator needs is for the equipment to stop working. One single day of non-operation means lost profit that you can never recover.
Keeping your car or truck wash equipment in top-notch condition includes checking and replacing defective photo-eyes. Sensors provide the critical signal to the wash computer. Therefore, it is absolutely necessary they operate properly. As the old saying goes, "junk in, junk out." A photo-eye could mean the marginal difference between profit and loss for your wash.
Common Problems
The number one reason for photo-eye failure is contamination. A car wash is ideally the best testing grounds for a photo-eye because of contamination. Practically, no other industry can compare to the wet, hostile environment of the car wash's dirt, steam, ice, snow, soap, film, grease and everyone's "favorite", fog. If a photo-eye can pass this test, you have a winner.
There are some sensor brands of this caliber on the market. They are able to withstand this type of abuse because they do not use a lens to magnify the light to the receiver eye. Lens-less eyes are usually designed as modulated infrared sensors (see figure 2).
The transmitter LED (light emitting diode) is turned on and off, acting as a pulse of light, invisible to the naked eye. The receiver is calibrated to the same frequency of modulation to accept the transmittal signal.
Just as a lighthouse penetrates the fog to warn an approaching ship of danger, the lens-less photo-eye cuts through fog, steam, dirt and grime to ensure your car wash trouble-free service. Relate the photo-eye made with a lens to a pair of glasses. If you walk into the wash wearing glasses, they immediately become fogged up. You must take the glasses off and clean them. This is a perfect example of the wrong photo-eye to use in a car wash. By removing the photo-eye made with a lens you eliminate the step of continual lens cleaning.
Misalignment is another photo-eye problem common to car wash facilities. In some cases, it is possible to judge visually if the eyes are out of alignment at an angle or askew to one another.
When installing photo-eyes at a distance of eight to twelve feet, it should be possible to pull a string between the two to check positioning. If the viewing angle of the photo-eye is eight degrees or greater, alignment should not be difficult.
The next common reason why so many photo-eyes fail is vibration. Have you ever seen a car or truck wash facility devoid of vibration? With arches turning on and off, and other assorted wash components in constant motion, vibration is certain to occur.
If a photo-eye system is difficult to align when installed, given the amount of on-site vibration, it is highly probable that proper alignment will be difficult to maintain. With a wide opening- angle, or "beam-spread", installation is not only simple, but vibration won't knock the eyes out of alignment.
Mounting plays an important role in photo-eye alignment. In the wash environment, eyes should always be mounted in a through-beam manner (figure 2). Properly mounted eyes promote reliability for the wash over the long haul.
A special word of warning: Do not use reflectors!! (see Pix) In car and truck wash applications, the use of reflectors is a bad idea. Condensation that forms on reflector faces may cause significant problems and they are prone to damage and mischief.
Last, but certainly not least, water leakage can cause photo-eyes to perform intermittently at best, or fail altogether at worst. As water leaks into the housing of the photo-eye, the internal components become damaged and condensation begins to form on the inside of the lens, fogging up glass and plastic lenses alike.
Check the rating on this eye to determine whether it was designed to withstand wash-down or submersion. A rating of IP67 means that a sensor will perform reliably in water. If the photo-eyes in your car or truck wash are not performing up to standards, replace them. Eliminating the problem sensor before it interferes with the performance of the equipment will save you money on those high volume days.
The Right Sensor
Selecting the right sensor for your application can be tricky, and turning the pages of photo sensor catalogs may only add to the confusion.
The components for most infrared systems used in the car wash industry include a transmitter, receiver, amplifier and socket. Don't be tempted to purchase a photo-electric sensor system based on price alone. The cost of installing quality sensor eyes that are made specifically for the car or truck wash is more than justifiable.
As an operator, you're looking for equipment that will perform reliably, day in and day out, with the least amount of maintenance. Remember, your best profit days are when you are managing and the wash is working. Quality eyes will help put you back in the driver's seat of your wash so you can do the important things like servicing and delivering a quality wash.
Light immunity rating, sensing range, strain relief and body style are other features to consider when selecting your sensors; and often the application will help narrow down your choices. For example, if you plan to mount photo-eyes at the entrance to the car or truck wash, a compact body style will simplify installation and service. These sensors should be fully encapsulated, resisting water leakage. The entrance area also subjects the photo-eyes to prolonged exposure to bright sunlight. To avoid intermittent interference, opt for a sensor with a rating of 50,000 LUX or above.
Although operators only need to cover a distance of approximately 10-50 feet, the sensing range of the photo-eye is extremely crucial in carwash applications. Photo-eyes with ranges of 120 feet or more are strongly recommended to ensure that you will have enough power to penetrate the harsh environment caused by dirt, water, soap, fog, etc.
Common applications
Now, let's take a look at some of the most common types of car or truck wash applications.
Self Serve Washes
In self-serve washes, the most common usage is on service-bay automatic doors. Photo-eyes are installed on entrance and exit doors to prevent damage to a car or to the door if the operator closes the door prematurely.
The sensors should be mounted on each side of the door in a through-beam configuration with the transmitter placed on one side and the receiver on the opposite side. (See pix) The amplifier is placed in a watertight enclosure or in the main control panel. As the car comes into or out of the wash, it breaks the infrared beam and signals the door to reverse. Other applications in self-serve washes include automatic entry systems, exit signs, and "unlimited time" self-serve bays.
"Unlimited time" self-serve bays offer extra value to your customers by allowing them plenty of time to clean their vehicles. This may be achieved by installing two photo-electric systems in the bay. One system is used to detect that a vehicle is present in the bay. The second system is used to reset the timer when that customer leaves to prevent the next customer from enjoying a free wash.
Rollover washes
Rollover washes require the car or truck to be driven into the wash and then the machine moves around the vehicle. Photo-eyes are used to position the wash equipment, measure the length of the vehicle and turn the equipment on and off as needed. The entrance and exit doors generally use photo-eyes to signal the PLC or industrial computer that the vehicle has entered or exited the wash.
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