投稿者: Fujiwara

What Is an Impact Roller?

An impact roller is a component designed to absorb the energy generated when heavy or irregularly shaped materials fall onto a conveyor belt, thereby mitigating the impact on the belt.

These rollers are typically mounted on devices known as idlers and installed at points where conveyed materials fall, such as hoppers or chute outlets. By dispersing the impact force, impact rollers help extend the overall lifespan of the conveyor system. Additionally, rubber impact rollers not only cushion the impact but also reduce noise and vibration associated with loading. They are also referred to as impact idlers.

Uses of Impact Rollers

Overview

Impact rollers are used to cushion the impact on conveyor belts and prevent damage. They are designed to absorb the shock from falling materials. With their high impact absorption capability, they reduce the risk of damage and abrasion to the conveyor belt, extending its life even under harsh operating conditions. Key installation points for impact rollers include:

• Loading Zones: Where materials fall from a height onto the conveyor belt
• Transfer Points: Where materials are transferred from different belts or different types of machinery onto the belt

Applications in Various Industries

Conveyor systems are utilized across various industrial applications to streamline production, packaging, and distribution processes. In the logistics industry, they are used for efficient sorting, loading, and unloading of parcels. In manufacturing, their primary use is for transporting parts, materials, and products.

In the automotive industry, conveyor systems are used on assembly lines to move car bodies between processes, efficiently supplying necessary parts for assembly. In mining, they transport ores from extraction sites to processing facilities, reducing production costs and improving operational efficiency. In food processing plants and packaging lines, conveyor systems are essential for automated transportation and packaging of food items. They are used in processes such as washing, heating, and packaging, contributing to improved production efficiency and hygiene management.

Impact rollers are effectively utilized in these industrial scenarios. For example, in mining, they are used to absorb the impact of handling ores and other heavy materials. In manufacturing, impact rollers are used on assembly lines to smoothly move parts and products. Additionally, impact rollers prevent slipping and smooth out vibrations, ensuring the safe and efficient movement of items during packaging processes. In the transportation sector, impact rollers aid in managing heavy loads, enabling efficient and safe transport. Specifically, they are used in baggage handling systems at airports and shipping facilities.

Principle of Impact Rollers

Impact rollers are manufactured by bonding a rubber coating onto a steel tube roller. This bonded rubber coating prevents surface separation and cushions the impact from falling materials. Impact rollers are attached to parts called idlers and used at necessary points on conveyor systems to mitigate impact.

Some impact rollers are equipped with rubber rings. These rubber rings, made from high-quality, durable rubber, enhance the roller’s impact absorption capabilities. The flexibility and elasticity of the rubber rings allow effective shock absorption even under heavy loads. This prevents damage to the conveyor belt and enhances its durability.

Types of Impact Rollers

Overview

Impact rollers come in various diameters and lengths to match the width of the conveyor belt and the material handling capacity. The required impact roller varies depending on factors such as the type of conveyed materials, conveyor speed, and load capacity. Selecting the appropriate product minimizes belt impact, abrasion, and damage.

Rubber-Coated Rollers

Rubber-coated impact rollers cushion transported materials, reduce the impact on the conveyor belt, and minimize operational noise. Some specialized rubber impact rollers include:

• Waterproof Rollers: Used in applications involving water or high humidity
• Extreme Temperature Rollers: Suitable for regions with extremely high or low temperatures
• High-Speed Rollers: Used on conveyor belts that operate at high speeds
• Low-Noise Rollers: Designed to reduce noise output in environments where noise control is essential
• Chemical-Resistant Rollers: Used in applications involving corrosive or chemically harsh conditions

Polyurethane Rollers

Polyurethane impact rollers are known for their durability, wear resistance, and low noise. They offer excellent resistance to abrasion, chemicals, and harsh environmental conditions, making them suitable for demanding applications.

What Is a Conveyor Pulley?

A conveyor pulley is a disc-shaped component used in belt conveyors to transmit power from the belt.

In a belt conveyor system, the conveyor belt operates as the drive pulley, which functions like a pulley to move the conveyor belt. There are various types of pulleys that play different roles, such as changing the direction of the belt or pulling it, and the belt conveyor operates through multiple pulleys positioned at key points of the belt conveyor system.

Uses of Conveyor Pulleys

Conveyor pulleys are primarily used in belt conveyor operations. Industries where conveyor pulleys are commonly used include:

• Steel and Coke
• Quarrying (Crushing Stones)
• Cement and Ready-Mix Concrete
• Asphalt
• Civil Engineering
• Thermal Power Plants
• Recycling
• Water Treatment
• Logistics
• Paper and Pulp

Additionally, pulleys themselves are used in various devices beyond belt conveyors, such as car engines, agricultural machinery, compressors, pumps, and office automation equipment.

Principle of Conveyor Pulleys

Overview

The main components of a conveyor pulley include the shaft, bearing, end disc (side plate), hub, and shell (outer ring).

The shell makes contact with the belt, while the end discs support it on both sides. The shaft rotates, transmitting power to the hub and end discs, causing the outer ring to rotate and move the conveyor belt. The bearing supports the shaft, ensuring it remains in the correct position.

Shell Processing

During belt conveyor operation, the conveyor belt and pulley can become misaligned. To prevent such occurrences, the pulley shell may undergo crown processing, where the diameter of the central part of the outer ring is made larger than that of the ends. Additionally, the surface may be coated with rubber (lining processing).

Types of lining processing include:

• Horizontal Grooves
• Double Helical Type (grooves angled toward the center)
• Diamond Type

The double helical type is highly effective in increasing friction with the belt and preventing foreign matter from entering. The diamond type features a larger rubber surface area in contact with the belt, enhancing friction and bearing larger surface pressure. Unlike the double helical type, it also easily accommodates bidirectional operation.

Types of Conveyor Pulleys

Overview

Conveyor pulleys primarily include:

• Drive Pulley (Head Pulley): Drives the belt conveyor
• Snub Pulley: Increases the wrap angle of the belt around the pulley
• Tail Pulley: Located at the tail of the conveyor
• Tension Pulley: Pulls the belt
• Bend Pulley: Changes the direction of the belt

Each type has its role, and selecting the appropriate one depends on factors such as the length of the conveyor and the type of material being transported.

Head Pulley / Tail Pulley

Belt conveyors have a head (drive side) and a tail. The pulley at the head is called the head pulley, while the one at the tail is called the tail pulley.

The pulley that drives the conveyor is known as the drive pulley, and it is generally the head pulley. However, in some cases, the head pulley and drive pulley are separate in belt conveyors.

Tension Pulley, Bend Pulley, and Snub Pulley

The tension pulley maintains the tension of the conveyor belt, preventing deviation or skewing. The bend pulley changes the direction of the conveyor belt. The snub pulley increases the wrap angle of the conveyor belt around the pulley, preventing the belt from slipping or sagging.

Selecting Pulley Size

The appropriate size of the pulley is closely related to the selection of the conveyor belt. For example, rubber conveyor belts typically require pulleys with larger diameters compared to resin conveyor belts. Additionally, the greater the tension on the conveyor belt, the larger the pulley diameter required.

A smaller pulley diameter causes the conveyor belt to bend more sharply. The sharper the belt bends, the greater the stress on the belt, increasing the likelihood of belt joints coming apart or detaching. If the pulley diameter is smaller than required, the belt may slip at the pulley. Larger pulley diameters reduce the bending degree of the conveyor belt, thereby minimizing stress and extending belt life. However, larger diameters generally increase the manufacturing cost of the pulley.

What Is a Bearing Temperature Sensor?

A bearing temperature sensor is a temperature sensor used to measure the temperature of bearings and detect abnormalities.

Bearings typically increase in temperature after the start of operation, reaching a steady state at a temperature 10 to 40°C higher than the ambient temperature after a certain period. If the bearing temperature does not stabilize and continues to rise abnormally, it indicates a malfunction that needs to be addressed. Bearing temperature sensors are used to detect such malfunctions early. Particularly critical bearings often use temperature sensors to prevent damage like seizure, which can lead to equipment downtime.

Uses of Bearing Temperature Sensors

Overview

Bearing temperature sensors are used to monitor the temperature of bearings in various machines. By measuring the internal temperature of bearings, they help quickly detect abnormal temperature rises, enabling rapid detection of malfunctions and prevention of accidents.

Uses of Bearings

Bearings are mechanical components used to support rotating bodies such as shafts smoothly and accurately. They are also known as bushings. Bearings are widely used in industrial machinery, automobiles, aircraft, railway vehicles, household appliances, and other industrial products.

In particular, in piston engines like diesel engines, bearings support the crankshaft at the correct position, allowing it to rotate within the engine block (main bearing). Diesel engines are used in various applications, including ships, power generation, and industrial uses.

Principle of Bearing Temperature Sensors

Causes of Abnormal Temperature Rise in Bearings

Bearings start to gradually increase in temperature as soon as they begin to operate, typically reaching a steady state after 1-2 hours. The normal temperature of bearings depends on the machine’s heat capacity, heat dissipation, speed, and load. If there is a malfunction, the bearing temperature will rise rapidly and become abnormally high. Common causes of abnormal temperature rise include:

• Extreme shortage or excess of lubricant, or inappropriate lubricant
• Improper installation of the bearing
• Insufficient internal clearance of the bearing or excessive load
• Excessive friction in the sealing device
• Creep on the fitting surface

Mechanism of Bearing Temperature Sensors

Bearing temperature sensors can estimate the internal temperature of the bearing by measuring the temperature outside the bearing chamber or directly measure the outer ring temperature of the bearing using oil holes. Some products can be directly screwed into the grease nipple mounting hole of the bearing.

The sensor mechanism for detecting temperature includes thermocouples and resistance temperature detectors (RTDs). A thermocouple is a temperature sensor that uses the electromotive force generated by the temperature difference between two connected metals. Thermistors and RTDs measure temperature by correlating material resistance with temperature. Thermistors are characterized by their ability to measure within a narrow temperature range with high sensitivity and small size. RTDs, on the other hand, can cover a wide temperature range with good linearity but are less sensitive than thermistors.

Types of Bearing Temperature Sensors

Various bearing temperature sensors are available on the market, with different operating temperature ranges, such as -40 to 105°C, -15 to 60°C, and up to 1200°C. Some products can sound an alarm at a specified temperature.

For diesel engines, bearing temperature sensors can be paired with lubricant oil sensors that measure the temperature of the oil rising to the piston crown, allowing for comprehensive temperature monitoring. Some products offer complete wireless capabilities through wireless communication and self-powering systems, and others are powered by lithium batteries.

Additionally, there are sensors that can simultaneously measure vibration speed, acceleration envelope, and temperature, as well as sensors that can communicate with tablets, smartphones, or smartwatches via Bluetooth. Many products are also equipped for cloud integration. Given their use in harsh industrial conditions, many sensors meet standards for waterproofing, dustproofing, fire resistance, and explosion proofing.

What Is a Wireless Charging and Monitoring Device?

A wireless charging and monitoring device is equipment that charges various devices (provides power) and monitors the charging status and battery condition without the need for wired connections through metal contacts such as terminal connections.

Wireless charging is used in a wide range of applications, from personal devices like smartphones and wearable devices to industrial equipment such as sensors, AGVs (automated guided vehicles), collaborative robots, and automated transport carts. The advantages include eliminating the need to plug and unplug power cables, reducing issues related to cable breakage, and avoiding connector wear and tear. In industrial applications, the absence of metal contacts also eliminates the risk of electric shock, greatly enhancing safety.

Uses of Wireless Charging and Monitoring Devices

Wireless charging and monitoring devices are used for wireless charging of various devices, both residential and industrial. Major applications include:

• Smartphones
• Wearable devices
• Industrial sensors such as temperature and pressure sensors
• AGVs (automated guided vehicles) and automated transport carts
• Industrial robots like collaborative robots

In particular, introducing wireless charging to AGVs allows automatic charging during downtime when the AGV is stopped for loading and unloading tasks, thereby efficiently utilizing standby time. The lack of metal contacts also removes the risk of accidents due to sparks or electric shocks, and reduces labor costs associated with charging tasks, thereby contributing to increased productivity.

Principle of Wireless Charging and Monitoring Devices

Overview

Wireless power transfer methods are broadly classified into two types: “radiative” and “coupling (non-radiative).”

“Radiative” methods use light such as laser beams or radio waves such as microwaves. These are suitable for long-distance power transmission but are currently limited to research stages due to significant energy loss and poor transmission efficiency.

“Coupling” methods efficiently transfer power over short distances and are the types currently being implemented. Coupling methods can be further divided into systems using magnetic fields and those using electric fields as the medium for power transfer.

Electromagnetic Induction Method

The electromagnetic induction method generates charging by creating an induced magnetic flux between the transmitting and receiving sides. When two coils are brought close together and an electric current flows through one coil, an electromotive force is generated in the other coil via the magnetic flux passing through the coils. This method is one of the most common for wireless charging due to its compact size and low cost.

However, the transmission distance is short, and charging cannot occur if there is misalignment between the transmitting and receiving sides.

Magnetic Resonance Method

The magnetic resonance method generates power for charging by resonating the magnetic field resonators of the transmitting and receiving sides. This method allows charging over longer distances compared to the electromagnetic induction method, and can transfer power over several meters. It is mainly being researched for charging electric vehicles.

Electric Field Coupling Method

The electric field coupling method uses electrodes placed facing each other between the transmitting and receiving sides. This forms a capacitor, and when high-frequency electricity flows through one side, electricity also flows through the electrode on the other side. This phenomenon is utilized for charging in the electric field coupling method.

While the transmission distance is short, similar to the electromagnetic induction method, this method is less affected by misalignment.

Types of Wireless Charging and Monitoring Devices

Various products are available for wireless charging and monitoring devices.

By application, there are charging devices for small devices like smartphones, equipment for transport vehicles like AGVs, and devices for industrial sensors. Additionally, wireless charging systems for electric vehicles are being developed, with demonstration tests being conducted for systems that transfer power non-contactly from ground-installed transmitting coils to receiving coils in EVs.

Wireless charging devices for industrial sensors may include features that allow real-time monitoring of temperature, pressure, signal power rate, sensor name, and charging level simultaneously with charging. Some products also come with waterproof and dustproof structures.

What Is a Solar Panel Efficiency Monitoring Device?

A solar panel efficiency monitoring device is a machine used to monitor the performance of solar panels in a photovoltaic system.

There are various types of products with different operating mechanisms, including devices that directly monitor solar panels, measurement instruments called CT sensors, and devices that directly obtain data from power conditioners. By using a solar panel efficiency monitoring device, it is possible to quickly respond to any issues in solar power generation, thereby enhancing generation efficiency.

Uses of Solar Panel Efficiency Monitoring Devices

The primary use of solar panel efficiency monitoring devices is to measure data such as power generation and provide information to determine whether the system is operating correctly. Some products, when used in combination with an internet connection, allow users to easily check the power generation status remotely from a computer or smartphone.

These functions enable effective maintenance and efficient operation of solar power generation facilities.

Principle of Solar Panel Efficiency Monitoring Devices

Overview

Solar panel efficiency monitoring devices mainly use systems that obtain data from power conditioners and systems that measure current values through wiring using measurement instruments like CT sensors.

Power Conditioner Monitoring Type

The power conditioner monitoring type of solar panel efficiency monitoring devices communicates with power conditioners equipped with communication functions via communication methods such as RS485 or TCP/IP to monitor the power generation status.

This allows for the acquisition of information such as the amount of power generated by each circuit (string) and the monitoring of power conditioner operation and faults. In the event of a power generation stoppage, it can also identify and predict the cause.

However, disadvantages include high installation costs, limited compatible power conditioners, and the inability to obtain data if the power conditioner’s communication infrastructure is faulty, even if power is being generated.

Current Measurement Type (CT Sensor Type)

Solar panel efficiency monitoring devices that use measurement instruments like CT sensors monitor by attaching the instruments to the wires that transmit power to the electrical grid, measuring voltage, current values, and power generation. CT in CT sensors stands for Current Transformer. Since it is attached directly to the wiring, it can be installed regardless of the type of power conditioner and can monitor each panel by installing it on each one. Another characteristic is that it is relatively cheaper to install compared to the power conditioner monitoring type.

Disadvantages include difficulties in pinpointing the cause of power generation decreases due to only measuring AC current values, making it hard to determine if the issue is due to abnormalities or weather conditions, and measurement errors compared to the actual power generation since current values are measured from the wiring.

Types of Solar Panel Efficiency Monitoring Devices

Various manufacturers offer a wide range of solar panel efficiency monitoring devices. Depending on the application, products are available for large-scale commercial use, such as power plants, as well as for residential use.

Some products feature unique functions, such as detecting user-defined percentage deviations from the average values within multiple strings and comparing power among strings, allowing for panel-based monitoring. This makes it possible to specifically detect and report individual panel faults. Other examples include:

• Residential products with easy-to-read measurement display panels
• Products that display self-sufficiency rates and CO2 reduction amounts in conjunction with home power consumption measurement
• Products designed for large-scale monitoring with excellent multi-site monitoring and cloud integration
• Products that are highly compatible with multiple devices such as PCs, smartphones, and tablets

Selecting the appropriate product based on the application is essential.

What Is a Wireless Control Relay?

A wireless control relay is a relay device that receives electrical signals and outputs digital signals to control machinery, using wireless communication methods such as Bluetooth.

Control relays receive external electrical signals and perform tasks like turning electrical circuits on/off or switching them. They relay input signals from sensors or push buttons to other devices. Communication methods vary by product, including Wi-Fi, Bluetooth, and sub-GHz band wireless. These relays are used in various industrial scenarios where wired installation is difficult or in coordination with wireless sensors.

Uses of Wireless Control Relays

Overview

Wireless control relays are used to receive signals wirelessly from sensors and push-button switches and control other devices or processes wirelessly. Specific applications include:

• Controlling industrial processes in conjunction with wireless temperature or pressure sensors
• Smart home automation
• Eliminating wiring in manufacturing and conveyance processes in factories

Applications in Manufacturing

In manufacturing, wireless control relays are used with sensors and switches in the following ways:

• Efficient transmission of trouble alerts
• Efficient reporting of task completion
• Switching the direction of conveyor belts
• Wire-free layouts allowing flexible layout changes
• Remote operation of forklift communication and shutter control
• Counting inspection results and distinguishing between good and defective products
• Activating AGVs (Automated Guided Vehicles) for parts transport
• Indicating vehicle entry and exit

Principle of Wireless Control Relays

Overview and Wireless Communication

A relay is a component that receives external electrical signals and controls the on/off or switching of electrical circuits. Wireless control relays use various wireless communication methods, such as Wi-Fi, low-power radio, Lora, LoRaWAN, and Bluetooth, for communication with sensors and target devices. The suitable data communication method is selected based on the product and application. For example, LoRaWAN offers excellent reception sensitivity and resistance to radio interference, enabling communication distances of over 10 km in ideal environments, making it suitable for wide-area operations.

Wireless control relays, like traditional relays, come in two types: mechanical contact relays and solid-state relays.

Mechanical Contact Relays

Mechanical contact relays operate by mechanically moving contacts to output a contact signal. They are composed of components like electromagnetic coils and contacts and are also known as electromechanical relays due to their operating principle.

When an input voltage signal is received, the internal electromagnetic coil is energized, acting as an electromagnet and moving the movable contact with the movable iron piece. The movable contact touches or separates from the fixed contact, outputting an electrical contact signal.

Solid-State Relays

Solid-state relays have no mechanical moving parts like contact relays and are composed of semiconductors and electronic components like triacs and MOSFETs. They electronically switch signals or currents/voltages on and off using these electronic circuits.

Types of Wireless Control Relays

Wireless control relays come in various types. In addition to the operational mechanisms of contact and solid-state relays, there are different types of contact configurations and output methods. The types of contacts include:

• Form A (Normally Open) Contact: Activated by the input signal
• Form B (Normally Closed) Contact: Deactivated by the input signal
• Form C (Transfer) Contact: Combines Form A and Form B, with each operating inversely to the input signal

Functionally, there are products designed to work with wireless pressure sensors or temperature sensors, products with integrated push-button switches, and products intended for smart home applications. The hardware aspects, such as operating temperature, vary by product. Products with an IP54 waterproof rating, for example, can be used in wet environments or outdoors.

What Is a Wireless Pressure Sensor?

A wireless pressure sensor measures pressures, such as gauge pressure, in factories and plants without needing wired connections for power or communication.

In many industrial settings, it is essential to measure and manage the pressure of gases and liquids, including gauge pressure, sealed gauge pressure, and differential pressure. Traditional wired pressure sensors require long power cables and can have installation limitations. Wireless pressure sensors eliminate these restrictions, allowing for installation in desired locations. The power sources are mainly divided into battery-powered and self-powered types. Additionally, some products are used in educational settings for scientific experiments.

Uses of Wireless Pressure Sensors

Wireless pressure sensors are used in various industrial applications, including power plants, chemical plants, oil refineries, and food processing facilities.

Many industrial processes involve the use of pressurized gases or pressurized containers. Monitoring pressure is crucial as pressurized leaks or container expansions can disrupt the safe operation of manufacturing processes. Primary uses include:

• Online and remote gauge monitoring
• Valve leakage monitoring
• Monitoring pipeline and filter blockages
• Measuring gas and liquid flow rates
• Tank level measurement
• Monitoring gas and liquid filters
• Process control in factories

Wireless pressure sensors are also used in educational settings for various physics and chemistry experiments, such as Boyle’s law and measuring pressure inside balloons.

Principle of Wireless Pressure Sensors

Measurement Mechanism

Wireless pressure sensors measure the pressure of gases or liquids via a diaphragm and convert it into an electrical signal using a pressure-sensitive element.

A semiconductor piezoresistive diffusion pressure sensor forms a semiconductor strain gauge on the diaphragm’s surface. The diaphragm deforms under pressure, causing a change in electrical resistance due to the piezoresistive effect, which is then converted into an electrical signal. The piezoresistive effect is the change in electrical resistivity caused by applied stress, different from the piezoelectric effect, which is the polarization phenomenon caused by stress.

A capacitive pressure sensor forms a capacitor with a fixed glass electrode and a movable silicon electrode. The change in capacitance due to the deformation of the movable electrode under pressure is converted into an electrical signal.

Power Source

Wireless pressure sensors come in battery-powered and self-powered or energy-harvesting types. Battery-powered types use various batteries like button cells, AA, AAA, and lithium batteries.

Self-powered types do not require batteries and operate by collecting waste energy from surrounding heat, vibration, etc. Energy sources include temperature differences, vibrations, sunlight, and magnetic fields. This eliminates the need for battery maintenance and reduces operational costs.

Data Transmission

Wireless pressure sensors use various wireless communication methods for data transmission to data loggers, such as Wi-Fi, Zigbee, Lora, LoRaWAN, and Bluetooth. The suitable data communication method is chosen depending on the product and application. For instance, LoRaWAN offers excellent reception sensitivity and resistance to radio interference, allowing for communication distances of over 10 km in ideal environments, making it suitable for wide-area operations. Additionally, some products enable status checking via smartphones.

Types of Wireless Pressure Sensors

Overview

Wireless pressure sensors come in various types, each with different specifications and features. The pressure range, durability, and suitable applications vary by product, so it is necessary to select the appropriate one based on the intended use.

Data Management

Some products allow data to be saved in CSV format for statistical maintenance and management of equipment. Products with mechanical pressure gauges equipped with pressure sensors and communication modules enable pressure readings on-site even when communication is unavailable. Sampling intervals vary by product, from 0.1-second units to minute units, and some offer real-time data display.

Waterproof and Dustproof

Products with an IP65 waterproof rating can be used in wet environments or outdoors. While many products are unsuitable for corrosive gases and fluids, some can measure contaminated water, steam, and slightly corrosive fluids.

Products with explosion-proof certification can be installed in hazardous areas handling flammable gases, such as petrochemical plants, paint factories, and chemical plants.

What Is a Wireless Temperature Sensor?

A wireless temperature sensor is a device that measures temperatures, such as those in pipelines, without the need for wired connections like power cables.

Traditional wired temperature sensors often require long power cables and can have installation limitations. Wireless temperature sensors eliminate these restrictions, allowing for installation in desired locations. They are used in industrial applications for monitoring pipeline temperatures, internal concrete temperatures, and other temperature-related monitoring. Additionally, they are used in educational settings for science experiments. The power sources are mainly divided into battery-powered and self-powered types.

Uses of Wireless Temperature Sensors

The primary use of wireless temperature sensors is for temperature monitoring in industrial applications. Main uses include:

• Measuring pipeline temperatures
• Monitoring machinery conditions (e.g., pumps, motors, compressors, gearboxes in process industries and semiconductor plants)
• Measuring internal concrete temperatures
• Temperature monitoring in retail and food industries (e.g., supermarkets, greenhouses, cold storage rooms, aquaculture facilities, refrigerated trucks)

Specifically, pipeline temperature and machinery condition monitoring are applicable in a wide range of industries such as power plants, chemical plants, oil refineries, and food processing facilities.

Wireless temperature sensors are also utilized in educational settings. Temperature-related science topics are covered from elementary to high school levels, allowing for various uses. They are employed in various experiments, including supercooling, distillation, and heat of neutralization, and waterproof models can be used outdoors.

Principle of Wireless Temperature Sensors

Measurement Mechanism

Wireless temperature sensors detect temperatures using common temperature sensors like thermocouples, thermistors, and resistance temperature detectors (RTDs). A thermocouple is a temperature sensor that uses the electromotive force generated by connecting two different metals with a temperature difference. Thermistors and RTDs measure temperature by correlating material resistance with temperature.

Thermistors are characterized by their ability to measure narrow temperature ranges with high sensitivity and small size, while RTDs cover wide temperature ranges with good linearity but lower sensitivity than thermistors. There are two types of thermistors: NTC thermistors, which decrease in resistance linearly with temperature increase, and PTC thermistors, which increase in resistance non-linearly with temperature increase. Common materials used are semiconductor ceramics primarily composed of metal oxides such as nickel, cobalt, manganese, and iron. RTDs mainly use platinum, nickel, and copper.

Power Source

Wireless temperature sensors come in battery-powered and self-powered or energy-harvesting types. Battery-powered types use various batteries like CR2032 button cells, AA, AAA, and lithium batteries.

Self-powered types do not require batteries and operate by collecting waste energy from surrounding heat, vibration, etc. Energy sources include temperature differences, vibrations, sunlight, and magnetic fields. This eliminates the need for battery maintenance and reduces operational costs.

Data Transmission

Wireless temperature sensors use various wireless communication methods for data transmission to data loggers, such as Wi-Fi, Zigbee, Lora, LoRaWAN, and Bluetooth. The suitable data communication method is chosen depending on the product and application. For instance, LoRaWAN offers excellent reception sensitivity and resistance to radio interference, allowing for communication distances of over 10 km in ideal environments, making it suitable for wide-area operations.

Types of Wireless Temperature Sensors

Wireless temperature sensors come in various types, as mentioned earlier. They are categorized based on application, such as industrial pipeline measurement, machinery measurement, and scientific experiments in educational institutions.

The temperature measurement range varies by product, so selecting the appropriate one is necessary. Measurement intervals also vary by product, and some offer real-time data display. Products with IP66/IP67 waterproof ratings can be used in wet environments or outdoors.

Moreover, some products have explosion-proof certification, allowing installation in hazardous areas handling flammable gases, such as petrochemical plants, paint factories, and chemical plants.