Applications of CO Sensors in Smart Homes and their Installation Position

20180528111441

In recent years, the resident income is continuously increasing, consumption demand is upgrading and electronic information technology is rapidly developing. With the active participation of big enterprises and powerful push of policies, the construction of IoT is being accelerated. The essence of IoT is to connect every thing to cloud platform via information sensing equipment, so as to intelligently identify and manage them. Sensor is the core of IoT. With the development of IoT in China, sensors has been in the air waves.

People are now pursuing higher level of enjoyment, so smart household facilities are specifically developed. Yet the constitute of a smart home requires many different sensing modules. Next, let we ISWeek present the sensors used in smart homes.

  1. A comfortable home needs fully functional gas measurement facilities

In modern household environment, people usually expect comfortable surroundings, thus a sufficient gas measurement system is principle for a household system, which shall include sensors detecting PM2.5, CO, CO2, O2, VOC, formaldehyde and air quality.

  1. Healthy regulating system of humidity and temperature

Human bodies are relatively sensitive towards the temperature and humidity in the air. When the humidity is too high, people will feel uncomfortable; but if humidity is too low, the skin will become very dry. In a smart home, there will be a automatic regulatory system consisted of humidity and temperature sensors to provide a better living space.

Here ISWeek will mainly talk about CO sensors. Why?

It can often be seen in news that someone was carbon monoxide poisoned and sent to hospital. We will wonder, we can be under life risk even just in a shower, so what can we do to safeguard our lives? This question is especially concerned for those parents who care a lot about their young kids. Then, how can we prevent CO poisoning and save our lives?

First we should understand what carbon monoxide poisoning means. It typically caused by breathing in incomplete burned carbon. CO is a colorless and odorless gas, that’s why it has a frightening name called “silent killer”. Carbon monoxide poisoning often occurs from usage of heaters or cooking equipment that run on carbon-based fuels and obstructed ventilation. The news mentioned above can be taken as examples, in which people use gas water heater with no ventilation.

To prevent being poisoned by CO, people should improve their crisis awareness and open ventilation window or turn on vent fan when taking showers. Keep this in mind especially in winter, which is the peak of carbon monoxide poisoning, for that people may prefer to close ventilation windows in order to keep warm. In some old house, the water heaters are installed to connect with kitchens and they share the same ventilation system, which is putting the family under high risk of CO poisoning. Moreover, some water heaters are worn down by years without repair. They may produce more CO than expected and cause intoxication accidents.

CO sensors can be installed indoors to prevent these accidents. The sensors can measure CO concentration and make sound-light alarm immediately when gas leakage is detected. If someone is poisoned and falls into a faint in a rental house, others can find out and help, thus a lethal accident is avoided.

ISweek supply CO sensor 3SP-CO-1000 with our expertise. The characteristics of this product are as follows:

15x15 Carbon Monoxide Sensor (CO Sensor)
  • Compact size and low profile (20x20x3.8 mm)
    • Fast response (< 15 seconds)
    • Long-term stability (through 5000 ppm overload)
    • Low power (0 mW@0mV offset)
    • Separate calibration (Traceable NIST)
    • ROHS compliant

Livelihood Applications of Semi-conductive Sensors

As a converter to convert volume fraction of a certain gas into corresponding electrical signal, the Semiconductor Gas Sensors are mainly applied for civil use. It is for that these sensors are relatively cheap while their performance can meet the requirements of home alarms.

To be specific, gas sensors are used in following applications: in kitchens, sensors detect leakage of natural gas, liquefied petroleum gas and city gas. They also measure gas generated by microwave ovens and control them while cooking. Sensors detecting CO2, smoke and O3 are used to control the automatic operation of air purifiers or fans. In some high-rise buildings, gas sensors are used to detect fires and make alarms.

At present, with the development of gas sensitive materials, gas sensors are featuring with high sensitivity, stable performance, simple structure and compact size. Their price are low but their selectivity and sensitivity are enhanced.

ISweek supply semi-conductive metal-oxide sensor type TGS2611 and TGS2610, and their corresponding module FSM-T-01 and FSM-10H-01. The characteristics of these products are listed below:

日本figaro 可燃气体传感器/天然气传感器

The characteristics of TGS2611:
* Low power consumption
* High sensitivity to methane gas
* Long life with low cost
* Simple application circuit

日本figaro可燃气体传感器/液化石油气传感器
The characteristics of TGS2610:
* Low power consumption
* High sensitivity to LP and gas containing LP (propane and butane
* Long life with low cost
* Simple application circuit

Pre-calibrated Methane Gas Sensor Module

The characteristics of FSM-T-01:
*High sensitivity to methane gas
* Quantitative output of Gas concentration in UART digital signal
* programmable settings of alarm point output
* Factory calibration, temperature compensation.
* Compact in size, low in cost.

Pre-calibrated Combustible Gas Sensor Module

The characteristics of FSM-10H-01:
* High sensitivity to propane, butane and H2
* PWM, USART digital output proportional to gas concentration
* Maintenance free
* Compact in size
* Conform to RoHS

 

Importance of Gas Sensors in Storage of Fruits & Vegetables

According to the Analysis Report of Market Research and Investment Forecast of Cold-Chain Logistic Industry in 2013 – 2017, in China, the loss ratio of agricultural products astonishingly reaches up to 25~30% per year in logistic processes including picking, transportation and storage, and this is the key factor for the high prices of fruits and vegetables.
The concept of refrigeration may have been known to all, but the concept of CA cold storage may not be the case. CA cold storage is the abbreviation of controlled atmosphere cold storage for fresh agricultural products, which is one of the most advanced, effective and widespread preservation technologies.
However, different from its scale development abroad, the popularity of CA cold storage remain sluggish in China due to various reasons. Statistically, among over 30 thousand agricultural fresh-keeping storehouses in China, only 5~7% of them adopts CA technology. In developed countries, over 80% of edible agricultural products are of modified atmosphere packaging, while in China there are only 2%.
20180514120108
CA cold storage, or say modified atmosphere storage, adds gas component adjustment to refrigeration. By controlling conditions like temperature, humidity, concentration of CO2, O2 and ethylene, the respiration of fruits and vegetables is restrained, the metabolism of them is suspended, so that the freshness and commodity of these products can be better preserved, and their storage period and refreshing time can be extended.
The storage period in CA cold storage can be nearly double than it in common refrigeration. After being taken out of the CA cold storage, the fruits and vegetables “awake” from their “dormancy”, so their length for preservation (shelf lives) are prolonged by 21~28 days, which triple or even quadruple that of fruits from common refrigeration storage.
The reason for CA cold storage to be capable of prolonging refreshing time is that it is particularly strict on controlling dehydration of fresh agricultural products. Instead, common refrigeration storage depends only on cooling system which can do nothing on product dehydration, not to mention extending length of preservation.
Compared with common refrigeration storage, a CA cold storage makes higher profits while takes higher construction cost. The extra cost goes to a whole set of air modifying equipment and airtight construction. Though the initial outlay of a CA cold storage is relatively high, in long term it can make large economic benefit after coming into service, especially when used for those out-of-season species with high additional value, like kiwi fruits and large cherries. It is proved by facts that the high investment in CA preservation will surely bring about high market return. That’s why CA cold storage is widespread in western countries.
20180514120128
It takes only two steps to transform a common refrigeration storage into a CA cold storage. First, enhance airtightness of the storage. Usually atmospheric modifying is to add CO2 and N2 to prolong refresh time, which means gas leakage from both inside and outside should be prevented. Second, add atmospheric controlling equipment. The main equipment for modified atmosphere packaging includes CO2 maker, N2 maker, ethylene removing machine and O2 removing machine, etc.
Fruits and vegetables are still animated after collected. In storage they keep on metabolic activities, mainly respiration, normally, showed as consuming oxygen and releasing carbon dioxide and some heat. Thus, control on concentration of O2 and CO2 in the whole storage environment can significantly increase the storage lives of fruits and vegetables in it.

The design purpose of SST O2 sensor Lox-02 and CO2 sensor MINIR is to modify the atmospheric environment in the whole storage through accurate measurement on concentration of O2 and CO2, so as to extend the expiration date of perishable foods.

LuminOx Fluorescence Optical Oxygen Sensor (O2 Sensor)

 LOX-02 LuminOx Fluorescence Optical Oxygen Sensor (O2 Sensor) BENEFITS
• Low power
• Can also measure O 2 % & barometric pressure
• Suitable for battery power use
• Long life
• High accuracy
• Small & compact
• Low cost
• Maintenance free
• Contains no hazardous materials
• Connects directly to microcontroller without any additional circuitry.
• Factory Calibrated

LOX-02 LuminOx Fluorescence Optical Oxygen Sensor (O2 Sensor) APPLICATIONS
• Oxygen Detection
• Portable Equipment
• Breathing Apparatus
• Inerting
• Medical
• Lab Equipment
• Agriculture
• Incubation
• Fire Prevention
• Flue Gas in Condensing Boilers

Low Power High Performance NDIR CO2 Sensor

Low Power Carbon Dioxide Sensor (NDIR CO2 Sensor) MinIR

MinIR is an ultra low power (3.5mW), high performance CO2 sensor, ideally suited for battery operation and portable instruments. Based on patented IR LED and Detector technology and innovative optical designs, MinIR is a third generation product from Gas Sensing Solutions Ltd – leaders in IR LED CO2 sensing.

• Ultra-low Power 3.5mW
• Measurement ranges from 0 to 100%
• 3.3V supply.
• Peak current only 33mA.
• Compact 20mm diameter package

Perishable products, like fruits and vegetables, will keep on metabolic activities after collected, which means that they will consume oxygen (O2) while generate heat, CO2, moisture and probably ethylene. In this period the plants will gradually be mature and resolved into undesirable status.
Therefore, it’s a challenge to guarantee the integrity of products in transportation and storage of perishable foods. During transport process, four essential factors need to be considered — quality, temperature, relative humidity and gas concentration. Quality — the initial fine quality of fruits and vegetables shall be kept; temperature — with temperature lowered by 10℃, the metabolic rate will decrease by half; relative humidity — the quality of products will be severely affected if they are dehydrated by 2%; atmospheric environment control — if O2 concentration decrease from 21% to 2%, the metabolic rate will decrease by 30%.

The graph below shows the effect after adding an atmospheric control system.
image010

In the places where these factors are appropriately arranged, the storage life of fresh agricultural products can be apparently extended by controlling and altering the environment. By slowing down the metabolic rate of these products, their natural maturity can be delayed while their taste and flavor remain unchanged. Therefore, in the storage process of fruits and vegetables, atmospheric control becomes the most crucial part in the design of a CA cold storage.

The Application of O2 Sensors in Tunnels

20180413084349

Chola Mountain is the only way that must be passed of 317 National Highway, the lifeline from Sichuan to Tibet. Chola Mountain Tunnel Project, which locates between Ganzi Tibetan Autonomous prefecture and Dege and Gamtog, is a crucial project to go through this mountain, and the first extra-long highway tunnel built on over altitude of 4300m in the world. The project is consist of two major parts: the tunnel and the approach. The tunnel, with total investment of 1150 million yuan, is a two-way two-lane road of 7 km length, which can endure a maximum traffic flow of 5000 vehicles per day.

For a long while, Chola Mountain has been a “bottleneck” of this highway tunnel. Commonly, it takes more than an hour to climb over Chola Mountain in normal speed, and takes near 3 hours in winter on icy road. Once traffic control is implemented, this lifeline road will be completely cut. On Nov. 10th, this situation is finally changed. After over 10 years of scientific research and 5 years of tough construction, Chola Mountain Tunnel, whose overall length is 7079m, is formally run through. If things go well, the tunnel can be open to traffic at the end of 2017, sweeping away the long-lasting traffic bottleneck thoroughly. Hereupon the economic development of impoverished counties like Dege can be boosted.

Without doubt, Chola Mountain Tunnel is of great significance. Whereas to implement this construction at a place where is of high altitude and annual average temperature is lower than minus 18℃, the first problem that needs to be solved is oxygen supply. Lack of oxygen, people will have trouble at work, even the machines may also be malfunctioning. According to a relevant official in Southwest Institute, oxygen content inside the tunnel may only be a half of that in Chengdu Plain. Since 2004, the institute has started the research on “Construction Technique of Extra-long Tunnels under Conditions of High Altitude, Low Temperature, Pressure and Oxygen Content”.

What can we do to deal with anoxia? To solve this problem, the construction organization specially built an oxygen station outside the tunnel, which can constantly transport oxygen into the tunnel. Nevertheless, actual operation is far more complex. In August, the research group members came to Chola Mountain again for exploration, and what happened then impressed their technician Zhang Bo deeply. Roadway on Chola Mountain winds a lot, so it needs to be highly concentrated to drive upwards. The landscape is beautiful, but with the altitude becoming higher, the enjoy is replaced by discomfort like chest distress and dyspnea. “We already felt uncomfortable on the mountain, but it was worse inside the tunnel.” said Zhang. Although the oxygen problem is solved, new coming staff still need to adapt in plateau construction. Sometimes they need to uptake oxygen in medical room after several hours of working. In fact, in order to accelerate the project, some workers even carry an oxygen bottle with them while working. “We worked for a while, and came out to breath oxygen. It’s hard for people to imagine if they haven’t experience it.”

In tunnels and high altitude places, low concentration of oxygen will lead to chest distress and dyspnea to people. an oxygen station can improve the condition, yet it may push the oxygen concentration inside the tunnel to an excessive level, causing oxygen toxicity. Therefore, it is important to monitor oxygen concentration in real time. ISWeek would like to supply electro-chemical O2 sensor type O2-M2, which can effectively solve this problem. Features of this product are as follows:

  1. The measurement range of this product is 0~25%
  2. Linear output
  3. Its signal is easy to process
  4. Service time of 2 years

The chart below is a comparison between O2 sensor O2-M2 and 40XV from British City Company, which is popular in the market:

O2-M2

4OXV

Brand

AlphaSense

City

Principle

Electrochemistry

Electrochemistry

Range

0~25%VOL

1~25%VOL

Response time

15 seconds

15 seconds

Sensitivity drift

1%/Month

2%/Month

Service life

2 years

2 years

From the comparison above, it’s clear that O2-M2 and 4OXV are similar in performance parameters, but O2-M2 serves better in sensitivity drift.

Agricultural IoT: Great importance of CO2 Sensors in Greenhouse

Greenhouse, or say glasshouse, is a facility used for plant cultivation. With photo-permeability and capability of heat preservation (or warming), a greenhouse can provide a warm place to breed and increase yield in periods which are not suitable for plant growth. Greenhouses are often used to grow warm season vegetables, flowers and woods in low-temperature seasons. It’s a relatively enclosed environment  in which plants continuously conduct photosynthesis, thus CO2 concentration inside the greenhouse is apparently different from outside. CO2 content in the greenhouse directly affects growth of plants, for that sufficient CO2 increases chlorophyll content in plants leaves, making them glossy and green. Plants bred with sufficient CO2 bloom earlier and drop fewer flowers and fruits. Their leaf branches grow healthily and fruits are of good quality, so that they can come into market ahead of time in larger production.

20180417093244

Influence of inadequate or excessive CO2 to plant growth
Inadequate content of CO2: CO2 is the “food” of plants. The low concentration of CO2 will make the plants ”starving”, and significantly lower plant biomass. For example, lacking of CO2, vegetable leaves would lost their gloss and  grow slower. It would bloom later with fewer female flower, and its flowers and fruits fall off more. Its leaves are lower, rough and uneven in surface. The leaves may be vertical to the main branch or hang down. It will bear more heteromorphic fruits and fewer high-quality fruits, while the total yield is low.
Excessive content of CO2:  Excessive CO2 content often curves vegetable leaves and influence normal photosynthesis, which will impede plants from absorbing oxygen and proceeding well-balanced respiratory metabolism.
Therefore, in order to enhance vegetable yield,  farmer households often add air fertilizer in greenhouse  planting (At present air fertilizer are mainly CO2, which is an essential element for plant  photosynthesis. Within limits, the higher the concentration of CO2 is, the stronger the photosynthesis will be, thus CO2 is the best air fertilizer.) to increase CO2 content. So how to decide when to add CO2 in the greenhouse?

20180417093258

During daytime, in greenhouse the photosynthesis of plants are prosperous, so CO2 concentration decreases sharply. At night, photosynthesis stops, and plants release CO2 during respiration, so CO2 concentration increases. Greenhouse cultivation keeps plants grow in a relatively airtight place, where CO2 concentration reaches changes greatly in a day. Before sunrise the concentration reaches 1000~1200ppm at max, 2.5~3 hours after that the concentration drops to around 100ppm, which is only 30% of atmospheric concentration, and does not recover to atmospheric level until 4 PM. Commonly, CO2 concentration that vegetable requires is 1000~1500ppm, which means that inside the greenhouse CO2 deficiency is so severe that it has become an important factor that influences vegetable production. Installation of CO2 sensors in greenhouses can ensure that alarms can be made when CO2 concentration is under requirement, so that air fertilizer can be used. In this way, edible mushrooms, flowers, herbal medicines bred in green house can be of high quality and come into market earlier. CO2 sensors decide the growth and development, mature period, stress resistance, quality and quantity of crops.
Therefore, it appears to be very important to control CO2 concentration in a greenhouse.  At present, IR CO2 sensors, which are popular in the market, are designed mainly based on principle of double IR beam. The performance of these sensors are similar, and power consumption of the mainstream products are all about 100mW.
However, given the requirements of agricultural IoT, wireless module and battery powered products, NDIR CO2 sensor of low power consumption is an ideal choice. Currently the CO2 sensor of lowest power consumption worldwide is GSS COZIR-A from the UK. It samples twice per second with power consumption of only 3.5mW.

Ultra Low Power Digital Output NDIR CO2 Gas Sensor

COZIR-A
Advantages of CO2 Sensor COZIR-A
1. The equipment is of reliable performance and compact size, making it portable and easy to install;
2. Multiple wireless sensors are integrated, so that multi-parameter concurrent monitoring between joints can be implemented. the sensors are capable of calculation and storage, so they can perform relatively complex monitor according to environment change.
3. Wireless sensors with high accuracy. Transmission between joints, host and sensors are accomplished by wireless  transmission. Systematic monitor and protective measures are added into the low power consumption design.
4. Except for the system, data can also be conveniently checked on the spot.

Liquid Level Sensors Advantages in Level Measurement and Differences to Liquid Level Switches

As science and technology rapidly develop, various methods to measure liquid level have been invented, from rulers used in ancient time, to photoelectric, ultrasonic and radar gauges used by now. Liquid level sensor is a kind of pressure sensor measuring liquid level, which is suitable for level measurement in industries like petrochemical engineering, metallurgy, electricity, pharmacy, water supply and sewage, environmental protection and so on. For that the domestic market of magnetic flap level sensors developing continuously, the level sensor industry enjoys a bright future.
The reason for the wide application of level sensors attributes to the principle and features of the sensor.
Level sensors (static pressure liquid gauge / level transmitter / liquid level sensor / water level sensor) is a kind of pressure sensor that measures liquid level. Inputting type of static pressure level transmitter (liquid level gauge) adopts advanced isolated diffused-silicon sensitive elements or ceramic capacitor pressure-sensitive sensors from abroad. Based on the principle that the static pressure of tested liquid is in proportion to liquid level, the sensor transfers static pressure into electric signal, and convert it to standard electric signal (commonly 4~20mA/1~5VDC) by temperature compensation and linear modification.
Level sensors can transfer the variations of material level parameters into standard current signal, and remotely transmit to operation controlling room for centralized display, alarming or automatic control of secondary meters or computers. With its favorable structure and installation methods, the sensor is ideal for continuous measurement of liquid and material level  in special conditions like high temperature, high pressure, strong erosion, easy crystallization, blockage-proof, non-condensation and powdery or granular materials. Therefore this sensor can be applied for measurement and control in many industrial processes.
Level sensors and level switches are two kinds of most frequently used liquid or material level measurement devices, but few people understand the relation and difference between them, which is important for device selection. Now please allow we ISWeek to demonstrate the relationship between level sensors and level switches.
Difference between level sensors and level switches
Level switch is a kind of controller which opens inlet or outlet water valve according to signal output by level sensors to keep a constant water level. In other words, a level switch outputs a switch signal after confirming level height, and then level sensor transfers this signal into electric signal and output.
The electrical signal can be processed, such as connect to PLC data collector or professional display device to output liquid level. Although sharing the same working principle, a level switch is a switch controlling circuit, while a level sensor is a circuit component for voltage and current transformation.
For liquid level measurement, we ISWeek would like to recommend two kinds of products: photoelectric level sensor and level switch sensor.
What is a photoelectric level sensor?
Photoelectric level sensors is a new contact-type of level measurement and control device. It works with the principle of light reflection and refraction when going through an interface between two different mediums. For that it is featured with simple structure, high positional accuracy, no mechanical components, high sensitivity, corrosion resistance, and compact size, the sensor is gradually accepted by the market.

  1. despite of other parameters like temperature, pressure, density and electricity, level output is only related to whether the probe touches the liquid level.  Thus this sensor is featured with high detection accuracy, high repeatability, fast response and precise level control. This sensor needs no calibration and can be installed and use directly.
  2. with a relatively compact size, the photoelectric level sensing probe can be divided an installed in limited space, which means that it is suitable for use in spacial tanks. Also, several photoelectric sensors can be installed in a single object to form a multipoint level sensor or transforming controller.
  3. Since that inside the sensor,all elements are encapsulated with resin, and that there are no movable parts, this photoelectric liquid level sensor can be highly reliable, long-lasting without maintenance.

British SST low-cost Liquid Level SensorsLLC200A3SH

Optomax Basic Series Liquid Level Sensors

LLC low-cost series liquid level sensors are used for single point. For mass OEM client, there is a special design containing an infrared emitter and a detector which are precisely located and installed to ensure that they can achieve perfect optical coupling in the air. When the conical end touches the liquid, IR light will transmit out of the conical surface, so that strength of the light reaches the detector will be weakened.
Features of low-cost photoelectric level sensor LLC200A3SH
(1)fast response,
(2)10mA driving current, photoelectric transistor switch output.
(3)working temperature:-20~85℃,M12 thread.
(4)lead: 250mm 24AWG,8mm, tin-plating.
Typical applications of low-cost photoelectric level sensor LLC200A3SH:
spring pool, leakage detection, automatic beverage dispenser, medical treatment, compressor, printer, water pump, household appliances, oil level monitor, HVAC, machine tool, high=low level switch, water level control, automotive electronics.
Electrical parameters of low-cost photoelectric level sensor LLC200A3SH

Supply voltage (Vs) At will
Supply current Nominal 10mA
Type of output Photoelectric tube (digital)
Output signal
Operating temperature 25 ~ 80°C
Storage temperature -30 °C ~ 85 °C

Ultrasonic Water Level Sensors Provide Real-time Flood Warnings in Iowa

To create the world’s most sophisticated flood monitoring and forecasting system, the Iowa Flood Center (IFC) uses more than 200 Senix ToughSonic 30 and ToughSonic 50 ultrasonic sensors to measure water levels in streams across the state. Data collected from the sensors are automatically sent to the Iowa Flood Information System (IFIS), where the real time monitoring information is integrated into an advanced hydrological model. System data and river stage hydrographs are shared with the public and emergency management officials.

With easy online access to the water level data from the sensors, Iowa residents and state agencies can now get the reliable, real-time information they need to manage flooding in their locales.

Ultrasonic sensors chosen for ruggedness and reliability

ToughSonic REMOTE 50 Ultrasonic Water Level Sensor

ToughSonic 50 Rear Mount water level sensor

The IFC needed a reliable and cost-effective way to get accurate, real-time stream-level readings. Project Engineer Daniel Ceynar decided to try Senix ultrasonic sensors because they had been used for years for water level measurement in the hydrology research labs at IIHR Hydroscience & Engineering at The University of Iowa. The University of Iowa has long been a world leader in hydrological research.

Senix ultrasonic sensors were selected because they are designed to easily integrate with other equipment; in this case with the system’s cellular modems, solar panels, on-board clock, and other equipment. Senix sensors also were also chosen for their ruggedness, programmability, and the reputation of Senix for excellent engineering support. “Senix sensors and the Senix technical team have been pivotal to the success of this project,” Ceynar said, noting that the IFC and Senix worked closely to design a special threaded collar for the ToughSonic 50 so it could be mounted to the IFC Stream Gauge enclosure using the same threading as the ToughSonic 30. That ToughSonic 50 Rear Mount model has since become a standard product for Senix.

The sensors are programmed for a measurement interval of between five minutes and an hour, using a boxcar average of a preset number of individual measurements. The system sleeps until it’s commanded to wake up to take measurement data and send it to the IFIS. Sensor data is provided using RS-485 serial data communications.

The entire IFIS flood warning system depends on the ruggedness and reliability of the Senix ToughSonic sensors and the IFC system. The Senix sensors are potted in water tight stainless steel housings and operate in 0-100% humidity over a temperature range of -40 to +70°C.

After assembly in the IFC lab, each stream gauge is submerged for three days to verify that it is water tight. This testing has proven useful. In the field numerous sensors have been submerged by flash flooding and once the flood waters subsided the sensors resumed sending correct stream level data without requiring any repairs.

“Once installed, the IFC stream gauges are practically 100% maintenance free,” Ceynar said. “Most stream gauge sites have not been re-visited since they were installed, 4+ years ago.”

Real-time water levels facilitate disaster management.

The Senix ToughSonic sensors have provided the IFC and the people of Iowa with critically important data for forecasting floods and managing the situation after flooding has begun. “The system—stream gauges and other Hydromet data—is routed through the IFIS where it is regularly used by all levels of government, law enforcement and the general public,” Ceynar said. “We’ve had first-hand experience working with our local emergency management coordinator during floods in 2013 and 2014 where we participated in the daily briefings using IFIS.” The stream gauges identify where the crest of the flood is located and track the crest as it approaches sensitive roads, bridges and towns.

Before the system was in place, it was common for emergency personnel to be dispatched to assess the flooding in threatened locations. But with the stream gauges collecting the data in real-time, emergency responders can focus on helping people instead of tracking flood waters.

See a video of a Stream Stage Sensor in action:

Iowa Flood Center a model for the world

Ceynar and his colleagues have been contacted by officials from other states, and from countries as far away as Australia. The stream gauges are also being evaluated by the Washington State Department of Transportation.

The State of Iowa is clearly on the forefront of flood control monitoring systems that allow everybody from private landowners to emergency personnel to make informed decisions during a flood event. “The IFC is the only flood center in the US, and IFIS is the only system of its kind that we are aware of,” Ceynar said. “We continue our efforts to create a National Flood Center.”

Senix is proud to work with innovative research and educational institutions like the University of Iowa both in the lab and in the field.

Application of Fluorescent Oxygen Sensors in Diffusion Type Oxygen Supply

High altitude anoxia has severe influence on people’s ability of thinking. At elevation of 1500m, the thinking ability starts to be affected, presented as restriction on new acquisition of complex intellectual activity. At 3000m, people’s thinking ability comprehensively decreases, especially in judgment. At 4000m, people would write clumsy handwriting in weird grammar. At elevation of over 5000m, people cannot concentrate on something like they usually do.
While the altitude increases, the atmosphere becomes thinner and the barometric pressure decreases accordingly, lowering the oxygen molecular number. (Please note that the above is talking about number of oxygen molecular, but not oxygen concentration.) Consequently, natural reactions of human body are intensified, leading to heart rate accelerates, reaction slows down, get emotional and immunity decreases, and causing symptoms like headache, ventosity, baldness, dyspnea, doldrums, lower sleep quality and hypomnesis. Being on plateau for long may induce high altitude heart disease, high altitude hypertension, or even acute lung or brain edema, which can possibly be lethal.
Under standard atmospheric pressure, the oxygen content in ambient atmosphere is about 21%(the percentage under standard conditions is 20.9%), and this is also the normal oxygen concentration for human beings who evolve for long and live on plain areas. The oxygen concentration keeps at about 21% from sea level to upper air over altitude of 10000 meters.

So,
What is it for?
That People get oxygen deficit on plateau where oxygen concentration is 21%?
It’s for that at different altitudes,
The oxygen partial pressure differs greatly.
On plateau, the air is thinner (total air pressure is relatively low), so although the oxygen concentration is the same, the partial pressure is lower than that in plain area. That’s why people get anoxia on highland. Most of us think only about oxygen concentration of oxygen(% vol). Now after understanding the difference and linkage between oxygen partial pressure and concentration, we can touch the truth of plateau anoxia.
Then, how can people adapt to the plateau oxygen-deficient environment? In this case oxygen fraction indoor shall be increased to improve the oxygen volume fraction in the air.
In recent years, the concept of diffusion type oxygen supply has been raised, and has been realized indoor by pressure swing absorbtion oxygenerator or liquid oxygen evaporator, as a solution for plateau oxygen-deficient problem. By installing indoor control systems, the oxygen concentration can be automatically adjusted.
When interior oxygen concentration reaches the upper limit (26%), oxygen supply system is automatically shut off; when oxygen enrichment is lower than the lower limit, the system is automatically started.
Therefore, it will be very important to monitor interior oxygen enrichment (which is based on oxygen partial pressure). For now most diffusion oxygen generating systems and oxygen enrichment systems are based on electro-chemical principles. However, the lifespan of electro-chemical oxygen sensors are relatively short, and the output of these sensors will attenuate with time goes by. This is a severe drawback that limits the development of such technology.
The oxygen sensor for diffusion oxygen generating system is required for high accuracy, high repeatability, long lifespan and no pressure dependence. It should also be easy to use and needs few maintenance and calibration. To meet these demands, SST company in Britain has developed oxygen sensor Lox – 02, which is based on principle of fluorescence quenching.

LuminOx Fluorescence Optical Oxygen Sensor (O2 Sensor)
The fluorescent oxygen sensor is designed based on principle of fluorescence quenching. Oxygen absorbs the blue part of spectrum in ray of light. Fluorescence of the special ruthenium compound stimulated by oxygen gets quenched, so that the strength of light is changed in relation to oxygen enrichment. Detection based on principle of optic oxygen, such sensors has no effects on ambient gas to be detected, and consumes no oxygen, which is greatly different from conventional oxygen sensors which consumes oxygen and change the proportion of ingredients of tested gas. Accurate value of oxygen partial pressure can be obtained by demarcating the time that strength of light is changed, and this value will not be influenced by pressure change. During demarcating the oxygen concentration, the sensor is completely inert and has no consumption on oxygen to be detected, while, the implanted pressure chip and software has calculated the concentration value. To read the value of oxygen partial pressure, barometric pressure and oxygen concentration, only a command is needed.

The Operating Principle & Application prospect of Hydrogen Fuel Cell

On March 5th, the first session of the 13th NPC was held in Beijing. In the government work report, the prime minister clearly mentioned that preferential policies for vehicle purchase tax of new-energy vehicles would be prolonged for three years, and restriction policies on second-hand vehicle migration would be comprehensively canceled. Undoubtedly, the development of new-energy vehicle has become an important trend of future automobile industry, but whether electric vehicle or hydrogen cell vehicle will take up the mainstream is still under discussion. Today let’s talk about one of the future development directions of new energy resources — hydrogen fuel cell.

The basic principle of hydrogen fuel cell is that: by the reverse reaction of water electrolysis, hydrogen and oxygen are respectively served to the anode and cathode. Hydrogen out diffuse from anode and react with electrolyte, and then released electrodes reach cathode through external load. The hydrogen fuel cell is a power generating device which transfers the chemical energy in fuel and oxidizing agent into electric energy. Outwardly, with anode, cathode and electrolyte, it seems like an accumulator, but substantially a hydrogen cell needs no recharging, but only hydrogenation. For instance, the battery of a simple electric vehicle is like a power preservation station, while a hydrogen cell is like a power generating station.

Operating principle of hydrogen fuel cell

By far, vehicle manufacturers are strongly promoting their electric vehicles, but there are two main problems faced by all-electric cars:

  1. Long waiting time. The electric vehicle needs to be charged before starting. Even by rapid charge, it takes at least 20 minutes waiting, which is hard to bear for most drivers.
  2. Lifespan and recycle of batteries. Commonly the lifespan of a lithium-ion battery is about 20 years, but due to the particularity of new-energy vehicles, when the battery capacity fades by 80%, the vehicle’s endurance mileage will significantly decrease. It means that in about 5 years, the batteries must be replaced. Whereas the recycle of batteries, requires high cost and tough technological problems, which urgently needs to be resolved. According to the prediction made by China Automotive Technology & Research Center, considering factors like car scrappage term and power battery life, between 2018 to 2020, the accumulative number of scrapped power batteries nationwide will reach a scale of 350 thousand tons.

On Feb. 26th, 2018, seven ministries including Ministry of Industry and Information Technology and Ministry of Science and Technology have jointly issued Interim Procedures of Power Storage Batteries Recycling Management of New-energy Automobiles. The involvement of policies will make positive contribution to the regulation of development of this industry, the integrated utilization of resources and the protection of the environment and human health, so as to push forward the sustainable and healthy development of new-energy vehicle industry.

A vehicle powered by hydrogen fuel cell is featured with high energy conversion efficiency, long lifespan, smooth performance, while its greatest advantage is that it has no pollution emission. Hydrogenation time for such vehicles in mass production now are within 3-7 minutes, which is the same as that for oil-fueled automobiles.

Hydrogen leakage may occur inside the hydrogen fuel cell during use. When the concentration of hydrogen reaches a certain point, it will cause explosion and lead to safety accidents. To avoid such things from happening, it is advisable to implant a hydrogen module in the cell, which can measure hydrogen concentration in real-time and give an alarm when the concentration reaches the safety range to warn the car driver.

We ISweek supply hydrogen module FSM-10H-01 (semi-conductive principle) with our profession. The features of this module are as follows.

  1. Small in size
  2. Low cost
  3. Factory calibrated
  4. Conform to requirements of RoHS
  5. RS485 output of digital signal in proportion to gas concentration
Pre-calibrated Combustible Gas Sensor Module

 

The Application of Combustible Gas Sensor in Urban Gas System

20180323113616

In this rapidly developing era, the demand of natural gas is driving the prosperity of whole gas meter industry. From the prospective of end-users, the popularity of urban gas is improving with the growth of urbanization and urban population, and thus the demand of natural gas for industrial use and domestic use will significantly increase. From the prospective of market opportunity, the increasing demand of domestic and industrial used natural gas is boosting the demand of gas meter. The huge market space has become a powerful driving force on gas meter industry.
Among 600 cities nationwide, only about 300 cities have laid natural gas pipeline. From now on, with the planning and construction of line three and line four of west-east gas pipeline project, the construction of regional and urban pipeline will develop in a rapid speed.
In order to ensure the safety of living, production, fabrication, transport and using, it’s very important to detect and monitor gas leakage and anti-explosion on each process. Meanwhile, relevant government bureaus have formulated standards of monitoring, and have entrusted Shenyang Fire Research Station in Ministry of Public Security to implement of publicizing, acceptance inspection and check of the corresponding standards.
For now, detection methods toward gas industry are:
Household use combustible gas is detected mainly by semi-conductor and planar semi-conductor elements, which primarily detects in the range of 0-10000ppm. The mainstream market is taken up by domestic products. Municipal administrative gas company majorly adopts catalysis elements which mainly detects in the range of 100%LEL. These elements are predominantly used on the storage, transportation and pipeline safety polling of gas, etc. Since 2007, IR gas sensors with proprietary brands start to appear in domestic market, thus IR gas sensors are gradually adopted as high-end gas detection products in gas industry. They are able to detect 100%LEL and 100%VOL. Especially, laser correlation technology can be applied in long distance polling in gas industry.
We ISWeek are glad to supply the semi-conductive sensor TGS2611 and its module FSM-T-01, the features of these products are as follows:

Features of TGS2611:

  1. Quick response
  2. High sensitivity
  3. Strong resistance against interference
  4. Long lifespan of 5 years
日本figaro 可燃气体传感器

Features of Pre-calibrated Methane Gas Sensor Module FSM-T-01:

  1. Adapt for sensor TGS2611
  2. Factory calibrated and temperature compensated
  3. Programmable setting alarm point output
  4. Gas concentration is quantitatively output in RS485 digital signal
  5. Compact size and low cost
Pre-calibrated Methane Gas Sensor Module