High Resolution CO Sensor with UL Certification

CO sensors from SPEC, which are mainly applied in smart buildings and air quality measurement, have obtained UL certification. Through UL independent tests, SPEC’s product 3SP-CO-1000 is confirmed to be compliant with UL2034 and UL2075.

Elements with UL certification boost customer’s confidence on using CO sensor 3SP-CO-1000 and other SPEC’s products.products. Usually, CO detection are implemented by electro-chemical sensors for their low power consumption, long service life, high selectivity and sensitivity.

Many commercial electro-chemical sensors in the market are large in size, expensive in price and low in performance, making them hard to be integrated into new applications.SPEC’s patented “silk-print” technology effectively reduces the size of conventional electro-chemical sensors while not lowering their performance, allowing them to be applied in smart homes and IoT. Also, SPEC’s capability enables mass production to cater to all these applications. The patented technologies of SPEC provide possibilities of new applications of outdoor air quality measurement. South Coast Air Quality Management Bureau of California have recently compared the performance of our CO sensor to their high-performance NDIR CO detector which values 10 thousand dollars and is calibrated once a month. The measurement level collected over two months from 80 ppb to 1 ppm have shown a relevancy of over 83%.

The newly come UL certifications have attracted many new customers to use our CO sensors in their security products. The high sensitivity allows this sensors to be applied in situations of harsh requirements, such as measurement of indoor air quality, outdoor pollution and fire alarm.

About Carbon Monoxide
CO is a high-toxic gas of no color, no smell and no taste. CO is one of the most important reason of poisoning accidents, and an important source of global air pollution. For now, 36 states of the USA require their dwellers to install CO detector in their homes, but only 12 states require them to be installed in hotel rooms, and 5 states in school buildings. Existing CO detectors are only for life safety (alarm when the concentration is over 400 ppm) but do nothing about explosure in low concentration of CO. Evidences show that such explosure (e.g. 20ppm) will lead to various health issues and do harm to pregnant women and their babies, cardiac patients, asthmatic patients, the weak, the old and even healthy people who do aerobics exercises. CO sensors, especially when used in smart city network, inter-connected buildings, smart homes, cellphones and other wireless wearable devices, can make people be aware of the air quality and safety of where they live in.

ISweek now supply CO sensors from SPEC, a supplier from the USA. The features of this product are as follows:

Classification, Development and Applications of Gas Sensors

With the development of petrochemical industry, the categories and applications of inflammable, explosive and toxic gases are also increasing. Once leakage of these gases occurs during production, transport or using, it will cause poisoning, fire or even explosive accident, which will severely prejudice the safety of people’s health and possession. Since that gas is diffusive, with the effect of external wind force and internal concentration gradient, after leakage the gas will diffuse along the ground surface, and form and enlarge a danger zone of combustion explosion or poison.

Gas sensors have been researched since 1930s. They were mainly used for detection and alarm of coal gas, LPG and natural gas. For now they are also needed to detect toxic gas including CO, NO2, H2S, NO, NH3 and PH3.

There are a wide range of gas sensors. According to various gas-sensing materials and their characteristics, the sensors can be divided into semi-conductive type, solid electrolyte type, electro-chemical type, contact burning type and macro-molecule type, etc.

  • Semi-conductive gas sensor

This type of sensors mainly adopts semi-conductive gas-sensitive materials. Since appeared in 1962, semi-conductive metal-oxide gas sensors have been widely applied for their high sensitivity and fast response. Currently they have become one of the most produced and widespread gas sensors. According to the different measuring methods of characteristic quantity, these sensors can be divided into two types: resistance type and non-resistance type.

The resistance semi-conductive gas sensors operate by detecting the changes of gas-sensitive component with the variation of gas content. They are mainly made of metallic oxide ceramic gas sensitive materials. In recent years, researches on compound metal oxidate and mixed metal oxides have been deepened, the performance and application range of such gas sensors are consequently enhanced. For example, WO3 gas sensors are capable of measuring NH3 in concentration range of 5 ppm~50 ppm, and ZnO-CuO gas sensors are highly sensitive to 200 ppm of CO.

The operation of non-resistance semi-conductive gas sensors bases on the principle that the resistance value changes with the change of gas content, thus changes the current or voltage. There are mainly MOS diode type, junction diode type and field effect tube gas sensors. Most of these type of sensors detect combustible gas like hydrogen and silicane.

 

  • Contact burning type gas sensor

This type of sensors includes direct contact burning type and catalyst contact burning type. Its operation principle is: when the gas-sensitive component is in power-up state, combustible gas burns due to oxidation or catalyst, which generates heat that increase the temperature of heating wire and change its resistance value. Gas concentration can thus be obtained by measuring the resistance value. These sensors can only measure combustible gas while they are not sensitive to non-combustible gas. For instance, sensors made of Pt wires which are coated with active catalyst like Rh or Pd possess a broad spectrum feature, which means that they can measure various combustible gases. Contact burning type gas sensors are very stable in ambient temperature. They are able to detect most of combustible gas under lower explosive limits. Therefore, such sensors are extensively applied for detection and alarm of combustible gases in petrochemical plants, dockyard, mine tunnels, bathrooms and kitchens.

Now we ISWeek supply combustible gas sensors, including products based on semi-conductor principle and catalytic combustion principle. The details of these sensors are as follows.

日本figaro 可燃气体传感器/天然气传感器

Combustible gas sensor TGS2611:

* Based on semi-conductor principle
* Low power consumption
* High sensitivity to methane gas
* Capable of filtering VOC gases like alcohol
* Long service life and low cost
* Simple application circuits

日本figaro可燃气体传感器/液化石油气传感器

Features of Liquefied petroleum gas sensor TGS2610:

* Based on semi-conductor principle
* Low power consumption
* High sensitivity to liquefied petroleum gas or gas containing LPG component
* Capable of filtering VOC gases like alcohol
* Long service life and low cost
* Simple application circuits

日本figaro 催化燃烧式可燃气体传感器

Features of Combustible gas sensor TGS6812:

* Based on catalytic combustion principle
* Linear output
* Long service life
* Low sensitivity to alcohol
* High sensitivity to hydrogen, methane and LP gases.

Correlations between Nitrogen Oxide(NOx), Volatile Organic Compounds (VOCs) and Ozone(O3)

Instead of PM2.5, O3 has become the “culprit” of air pollution in summer. Therefore, NOx, as an important component to generate ozone, draws the attention of environmental experts. How can nitrogen oxide influence the environment? And how can them be controlled to reduce ozone pollution? Environmental Protection Agency in Chengdu has publish a science popularizing column to answer these questions in detail.

Q: Is NOx important for the generation of O3?

A: In sunlight, a series of photo-chemical reactions will take place between NOx and VOCs, and generate secondary pollutants including ozone, formaldehyde and acetaldehyde. Ozone is a main factor for the reinforce of atmospheric oxidation. High concentration of ozone will turn into photo-chemical smog with a long time, and pose a detriment to the atmosphere as well as people’s health. However, it is “people” who cause ozone pollution: primary pollutants from burning coal, vehicle exhaust and petrochemical engineering, such as nitrogen oxide. In other words, NOx deeply participates in secondary photo-chemical reactions in atmospheric environment, making it one of the major cause of ozone generation.

Q: In order to reduce ozone pollution, how should NOx be controlled?

A: To control ozone pollution at the root, the emission of NOx and VOCs should be limited. Unfortunately, at present NOx emission of China takes up 16.4% of world’s total emission. Moreover, 50% of industrial areas in China are increasing NOx emission. In those densely populated urban areas, vehicle exhaust is also a main source of photo-chemical pollution.

Therefore, to prevent photo-chemical pollution, it is important to strictly obey the emission standards, improve the quality of oil products and working condition of vehicle engine, apply clean fuel and install exhaust cleanup devices. Meanwhile, management and limits on factory gas emission should be strengthened, and monitoring stations should be set up to supervise the conditions of photo-chemical pollution.

In short, although barely mentioned, NOx plays an important role in photo-chemical reactions which generate ozone. The products of such reactions can do great harm to human health, so outdoor activities should be lessened when there are O3 pollution.

Now, we ISWeek supply sensors to measure O3, NO2 and VOCs. The detailed information are as follows.

Ozone Sensor + Nitrogen Dioxide Sensor (O3 Sensor + NO2 Sensor)

The features of O3 sensor OX-B431:

  1. High resolution up to 15ppb
  2. Short response time of 45s
  3. Linear output, excellent linearity
  4. Little zero drift
Nitrogen Dioxide Sensor (NO2 Sensor) 4-Electrode

The features of NO2 sensor NO2-B43F:

  1. High resolution up to20ppb
  2. Short response time of 60s
  3. Linear output, excellent linearity
  4. Interference of O3 gas is filtere
Photoionization Gas Sensor (PID Sensor)

The features of PID-A1 Photoionization Gas Sensor (PID Sensor):

  1. Wide measurement range of 0~6000ppm
  2. High resolution of 50ppb
  3. Linear output
  4. No need of circuit design and easy to use
  5. With internal heater, the sensor can work normally under high humidity without being affected.
Photoionization Gas Sensor (PID Sensor)

The features of PID-AH Photoionization Gas Sensor (PID Sensor):

  1. Measurement range of 0~50ppm
  2. High resolution of 1ppb
  3. Linear output
  4. No need of circuit design and easy to use
  5. With internal heater, the sensor can work normally under high humidity without being affected.

 

PID sensors which can detect VOC gas

VOCs is short for “Volatile Organic Compounds”. When it’s written as VOC, it specifically means only one kind of them or a collective concept of all kinds of VOCs.

For various requirements of research, management or control, different organizations have different definition to VOCs. ASTM d3960-98 define VOC as any organic compounds that can participate in atmospheric photochemical reactions. EPA (Environmental Protection Agency of the USA) define VOC as any carbon compound that can participate in atmospheric photochemical reactions, except for carbon monoxide, carbon dioxide, carbonic acid, metal carbide, carbonate and ammonium carbonate. WHO (World Health Organization, 1989) defines TVOC as the general term of VOC whose melting point is lower than indoor temperature and boiling point is between 50-260℃. In Indoor Air Quality Standard published in China(GB/T 18883-2002), the definition of Total Volatile Organic Compounds TVOC is the general term of VOC whose retention time is between that of n-hexane and n-hexadecane through non-polar chromatographic column (polarity index<10) analysis with samples of Tenax GC and Tenax TA.

In the air, the existing organic matters are not limited to only VOCs. Some organics can exist in both gas state and particulate matter in room temperature. With temperature changing, the ratio of these two states of the matters will also change. Such organics are called semi-volatile organic compounds, or say SVOCs in short. Some organics can only stay in particle matters in room temperature. These organics are called non-volatile organic compounds (NVOCs). VOCs, SVOCs and NVOCs can all participate in atmospheric chemical or physical process in the air, some or which can do harm to human health. The environmental effects of such matters include the air quality, weather and climate.

ISweek now supply PID sensors from Alphasense which can detect VOC gas. The features of this product are as follows:

Photoionization Gas Sensor (PID Sensor)

Photoionization Gas Sensor (PID Sensor) – PID-A1

  1. Large measurement range of 0~6000ppm
  2. Minimum detectable concentration of VOC is 50ppb
  3. The light bulb is of 10.6eV
  4. Long service life of light bulb up to 5000 hours
  5. Be able to measure most VOC gases
  6. Linear output
Photoionization Gas Sensor (PID Sensor)

Photoionization Gas Sensor (PID Sensor) – PID-AH

  1. High resolution of 0~50ppm
  2. Minimum detectable concentration of VOC is 1ppb
  3. The light bulb is of 10.6eV
  4. Long service life of light bulb up to 5000 hours
  5. Be able to measure most VOC gases
  6. Linear output

Installation Instructions of Methane Leakage Alarm

In recent years, gas alarms are more or less used in office spaces, smart homes and factories. As fuel of natural gas and coal gas, methane is widely applied for civil or industrial use. A methane alarm is to measure the concentration of methane gas and make alarm when it reaches explosion point or a preset value, in order to drive ventilation, cut-off and spray system to prevent accidents like explosion, fire or poisoning. Now let’s see the correct installation method of methane alarm, so that it can protect our safety in daily life.

The correct position to install methane leakage alarm is: a place with good ventilation and 1.5 meters from the gas source.

  • natural gas, city gas, CO and smoke is lighter than fresh air, so if the alarm is used to detect these gases, it should be installed at 0.3m below the ceiling.
  • liquefied gas is heavier than air, so the alarm should be installed at 0.3m above the floor. If the alarm is to detect natural gas or CO, it should be installed at 1.4-1.7 m above the floor, since CO is toxic gas which will cause lethal accident even with a little amount.

 

The alarm should not be installed in the following places:

  1. Inside a closet or places where ventilation is hard; and places where can be easily smoked by lamp black.
  2. An environment with too much dust or suspended particles which may cause false alarm of the detector.

 

The alarm had better not to be installed in following periods:

  1. When the painting of a room is not completed
  2. When the decoration of a room has just finished and general ventilation is less than 5 days
  3. When there are new wooden furniture inside a room and general ventilation is less than 3 days
  4. When sprayed insectifuge, air freshener, hair spray or gel is used in a room and general ventilation is less than 4 hours

 

In the cases above, alarms should not be installed. If there are already alarms, please cut their power off and cover them with plastic bags or such materials, until the room has enough ventilation. Otherwise the alarm may be damaged or make false alarm (make alarm when there is no gas leakage), or its yellow light may blink and the alarm may be broken.

  1. The height of alarm installation should be 160—170cm for convenient maintenance.
  2. As a safety instrument, the alarm is equipped with sound and light display function. They should be installed in a place where it can be easily seen or heard, so that the technicians can eliminate a hidden danger in time.

3.there should not be strong magnetic fields around the alarm (like high power motor or transmitter) which can interference the normal operation of the instruments.

  1. For different density of various gases, the installation position of indoor probe is different accordingly. When the density of gas to be detected is greater than air, the probe should be installed at 30cm lower than the ceiling facing downward; when the density of gas to be detected is less than air, the probe should be installed at 30cm above the floor facing upward.

 

Here we ISWeek would like to recommend some methane leakage alarms which are widely used in smart homes. The first recommendation is Figaro combustible gas sensor/ natural gas sensor – TGS2611. TGS2611-C00 is the best choice for gas leakage detection, for that it is of small size and excellent response. TGS2611-E00 is equipped with extra filter casing to eliminate the interference of alcohol, so it has high selective sensitivity to methane gas. It is especially suitable for complex gas environment and high requirements in homes, making it an ideal choice of household gas leakage detection sensor.

In order to minimize the cost of development and manufacture, so as to make it more convenient for users to produce domestic natural gas alarm, we recommend a methane gas detecting pre-calibrated module FSM-T-01. FSM-T-01 adopts TGS2611 sensors and coordinates an improved classic circuit to measure the concentration of methane gas. It is pre-calibrated by Figaro’s high accuracy calibration equipment and manufactured with mature conditioning progress.

Pre-calibrated Methane Gas Sensor Module

 

2018 Technical Seminar of Sensors between ISweek and SST was Successfully Held

A sensor technical seminar between ISweek and SST was successfully held on July 16th, 2018 in Zhongke Mansion. Paddy Shannon, the technical director of SST, and Sports Chen, the Manager of ISWeek, attended this seminar, in which the technology of fluorescent oxygen sensors was mainly introduced.

The seminar started with a technical illustration made by Paddy. He introduced SST`s innovative concept and products to ISWeek.

Found in 2002, SST is a solution provider who designs and manufactures series of sensors measuring level, gas, temperature and humidity, pressure, speed and position. SST has been supplying reliable sensors and controllers for over 10 years. The primary goal of SST is to deliver the required sensing and control solutions to our customers which exactly meet their technical and commercial sensor requirements. Where a specific solution is required, SST Sensing Ltd will identify the suitable technology and use this as a building block to provide a bespoke customer solution.

SST is the specialist of fluid and gas sensing technologies. Though sales of oxygen and level sensors make up its main profit, SST has been endeavoring to develop more market with its new products. There are various series of SST sensors for customers to choose, while its engineers are willing to provide comprehensive application and technical supports.

In this seminar, Director Shannon highly recommended the following fluorescent oxygen sensors:

 

 

Paddy Shannon, the technical director of SST explained the working principle and advantages of their products, and also answered some questions that were frequently asked by customers.

Working principle of fluorescent oxygen sensors:

The detection of such sensors is based on the ruthenium polymer coating on the dichroic mirror, which reflects the blue light from LED light source and filters orange fluorescence. Fluorescence of the special ruthenium compound stimulated by oxygen gets quenched, so that the strength of light is changed in relation to oxygen enrichment.

Advantages of fluorescent oxygen sensors:

1.Long service life of over 5 years
2. No lead contained and RoHS compliant
3. Resistant against ambient pressure change
4. Capability of working in low temperature of -30℃
5. Digital output, 3.3TTL level output and simple signal processing

As Director Shannon sees it, the cooperation between SST and ISWeek is a improving success, and it is for that ISWeek always abides to its commitment to every customer. Therefore, ISWeek will make more efforts to ensure that all customers are aware of their great importance. Under this major premise, SST and ISWeek will work together to provide sensors and solutions catering to every customers` requirements.

Applications of CO, CO2 and Temperature&humidity Sensors in Underground Parking

This application is to measure the air pollution made by automobile exhaust, mainly the concentration of CO, in underground parking garages. According to practical demands or specific requirements of ventilation, the sensors measure air pollution index to control mechanical ventilation in an automatic energy saving manner.

The number of sensors (referring to number of fans), and typical sensing point (the default detection radius of the sensor is 5m) are determined by the controlled range of each draught fan.

To keep the indoor air quality in underground parking garages at a comfortable level, CO2, temperature and humidity should also be take into consideration. The content of CO2 can be measured as an indication of other pollution. The operation of air fans are determined by comprehensive evaluation, and ventilation systems are controlled according to the concentration of pollutants. In this way the in door ventilation and air quality can be bettered to a certain extent, for example, make alarm for CO and start up ventilation system for 30 minutes for CO2.

Now,  ISweek supply sensors that measure CO, CO2, temperature and humidity. The products and their features are shown below.

日本FIGARO 纽扣式一氧化碳传感器(CO传感器)

Features of CO sensor TGS5141:

* Super small size
* Battery driven
* High selectivity / repeatability to CO

* High linear output characteristic to CO
* Easy calibration
* Long service life
* UL compliant
* Conform to UL2034, EN50291 and EN54-31

日本FIGARO  红外二氧化碳传感器(NDIR CO2传感器)

Features of CO2 sensor CDM7160:

* Based on IR principle

* Double channel

* Stable performance

* High accuracy

Miniature Digital Relative Humidity and Temperature Sensor

Features of temperature and humidity sensor HTU21D:

* DFN packaging

* Digital output of temperature and humidity, I2C interface

* Full scale calibration

* Lead-free materials suitable for reflow soldering

* Low power consumption

* Quick response and extremely low temperature coefficient

Relevant Factors to Consider when Purchasing Gas Alarm Sensors

With the concept of smart home being popular and awareness of household safety being enhanced in recent years, the usage rate of gas alarm is increasing. Also, actions with alarm is becoming more efficient because of the combination of gas alarm and the control of smart home, making it more widely welcomed.

We know, the essential requirements for a household combustible gas detector, or say combustible gas alarm, are to be sensitive enough toward target gas while to featured with high stability and resistance against interference. During use, drift tendency may appear to the combustible gas sensor alarm to a certain extent, that’s why it’s hard to produce gas alarm of high performance and quality. Therefore, to buy a high-quality combustible gas sensor alarm is especially important.

Then, when purchasing a gas alarm, what factors related to sensors should users care about? In short, the following two points need careful consideration.

Gas type

The first point is what type the target gas is. Customers buy equipment according to the type of gas they intend to detect, since that gas alarm are usually not for general use. In different areas the content of fuel gas are also different, so the gas sensor to be selected shall be calibrated and tested with local gas content.

Generally speaking, natural gas alarms are for occasions using natural gas, manufactured gas and liquefied petroleum gas in a similar way. In occasions using lpg, general type combustible gas detector alarms calibrated by lpg can also be used.

Service life

When purchasing fuel gas alarms, the users should pay attention to the long-term stability and service life of the alarm. In a general way, the built-in detecting elements of the alarm, like combustible gas sensors, are often between 3-5 years. There may also be difference between domestic ones and imported ones. Users should consult about these issues to the retailers before purchasing. Here we ISWeek would like to recommend several types of combustible gas sensors:

日本figaro 可燃气体传感器/天然气传感器

Features of combustible gas sensor / natural gas sensor TGS2611:

* Low power consumption

* High sensitivity to methane gas

* Capable of filtering VOC gas including alcohol

* Long service life and low cost

* Simple application circuit

Pre-calibrated Methane Gas Sensor Module

Features of pre-calibrated methane gas module / natural gas module FSM-T-01:

* Digital quantitative output of Gas concentration in communication mode

* Resistant against interference of VOC gas like alcohol

* Programmable settings of alarm point output

* Factory calibrated and temperature compensation

* Small size and low cost

日本figaro可燃气体传感器/液化石油气传感器

Features of combustible gas sensor / liquefied petroleum gas sensor TGS2610:

* Low power consumption

* High sensitivity to LP and gases containing LP (propane and butane)

* Resistant against interference of VOC gas like alcohol

* Long service life and low cost

* Simple application circuit

Pre-calibrated Combustible Gas Sensor Module

Feature of liquefied petroleum gas module FSM-10H-01:

* PWM or USART digital output in proportion to gas concentration

* Resistant against interference of VOC gas like alcohol

* Maintenance-free

* Small size

* Conform to RoHS

Figaro Combustible Gas Sensor — Best Choice of Household Gas alarm

With 40 years of application and development, gas sensors and alarms have been successfully improved. For now the gas alarms can be warranted to operate 5 years without maintenance. It has become a standard manner to enhance the durability and to prevent false alarm with a built-in filter.

All Figaro combustible gas sensor — household gas alarms are equipped with built-in filter. The usage amount of filter materials allows the design of the sensor to conform to the required response time (≤30s) in European standards.

20180607145243 20180607145230

Figaro combustible gas sensors also have following features:

  • Each of the sensors are produced under strict control of temperature and humidity, and 100% complete inspection is done towards target gas of the sensors.
  • The sensors have traceable records, so that the manufacturing logging can be tracked by batch number.
  • To meet customers` need of accuracy, Figaro supplies several types of pre-calibrated modules including LPM2610, NGM2611,CGM6812. These modules are pre-calibrated under strict controlled conditions.

20180607145257

  • Figaro gas sensors conform to environmental protection regulations including ROHS and REACH standards.

20180607145309

  • Low power consumption. Figaro devote itself to the R&D of sensors of low power consumption. With the miniaturization of sensor chips, the power consumption of TGS2610/2611 is as low as 280mw.
  • Long service life. The expected life of TGS6810/6812 sensor is about 10 years.

CO poisoning caused by Using Air-conditioner in a Vehicle & Application of CO Sensor to Prevent Poisoning

With ambient temperature going down, the air-conditioners in vehicles are used by an increasing amount of people, some of which even fall into sleep in the care. This is very dangerous, for that every year there are deadly accidents nationwide due to sleeping in a car with the air-conditioning on.

The cars` doors and windows now are of excellent sealing property. When the car is in down time, the long-time running of the engine will emit CO that will be gathered inside the vehicle and mix with CO2 exhaled by people inside the car. As time goes by, people will unconsciously be CO poisoned.

Interview to Li Yanwei, deputy director of TCM hospital of Boxing County

CO is a kind of gas with no smell or color, so there is no way for people to sense it. After entering a human body, CO will lower hemoglobin’s capability of oxygen uptake, do harm to neural center, leading to dysfunction of human body including senses, reactions and comprehension.

Staying in an anoxic environment for 6 minutes will lead to brain death irreversibly, and if the time is over 30 minutes, people will die of heart ischemia and anoxia.

Interview to Li Yanwei, deputy director of TCM hospital of Boxing County

After being CO poisoned, even people feel dizzy and nausea, they will be hard to save themselves for limbs weakness, not to say if people fall into asleep and feel nothing. As the car is sealed and oxygen content is limited, CO2 exhaled will push CO2 concentration to a certain extent that makes people be into narcosis.

How can CO enter the vehicle?

Then, do you know how CO enter a car? Let’s see the following reporter investigation.

Interview: Shen Wei, automotive repairing technician

When the car is running, the engine rotate in a speed of 1500-3000 rounds/minutes, and there won`t be excessive CO in exhaust gas. However, when the engine is working in idle speed, large quantity of CO will be generated due to incomplete burning of gasoline.

In addition, the car itself is not a completely sealed space, but CO emitted by the engine will accumulate in it if the air-conditioner is left working after the car stops. Adding the CO2 exhaled, people in the car will be poisoned unconsciously over time, in severe cases the accident could be lethal.

Interview: Shen Wei, automotive repairing technician

CO can also get in the car from its trunk. No matter the air-conditioner is set to be internal or external recycle, CO will have its way to enter the car.

The air-conditioners can hardly work very well in winter, it is for that the car owner don`t know how to use them in a proper manner. So what`s the right way to use air-conditioner for warmth in winter?

Interview: Shen Wei, automotive repairing technician

To use air-conditioner for heat directly will wear out the accumulator of the car. The engine start power supply only after the car is running. The right way to use the air-conditioning is: first, start the engine for preheating. When the temperature pointer of the engine goes to the middle, turn on heating, and set air circulation to be external recycle so that cool air in the car can be expelled. After 2-3 minutes, turn air circulation to be internal recycle.

In order to prevent such accidents, ISweek supply CO sensors to monitor CO concentration in real-time. When CO concentration reaches a certain level, the sensor will make alarm. The details of CO sensors are shown below: