月: 2022年12月

What Is a Heat-Resistant Glove?

Heat-resistant gloves serve as protective gear, shielding workers’ hands and arms from the risks associated with exposure to extreme temperatures, both high and low.

These gloves are crucial in research facilities dealing with temperature extremes and in industries where materials like resins, metals, and glass are melted, offering protection from burns and frostbite.

Materials such as cotton, silicone, aramid fiber, aluminum coatings, and polyurethane are used in their manufacture, chosen for their heat resistance and suitability for the specific working environment.

Uses of Heat-Resistant Gloves

High-temperature applications include food processing, glass manufacturing, steel production, and laboratory work, while low-temperature uses cover freezer operations, fishing, and handling liquid nitrogen.

In food processing, cooking gloves are employed for preparation, and oil-resistant silicone gloves prevent burns. Silicone gloves are preferred in food handling for their resistance to contamination, though they lack thermal insulation, necessitating the use of inner gloves for added protection.

Gloves used in glass and steel manufacturing need to withstand temperatures ranging from 500℃ to nearly 1,000℃, with those undergoing an aluminum vapor deposition process being highly sought after for their superior heat resistance.

For cold environments, such as in ice packing or outdoor work in the fishing industry, polyurethane gloves, which remain flexible at temperatures as low as -60°C, are common. Handling extremely cold liquids, such as liquid nitrogen, requires gloves durable to -196°C, typically used in laboratories and the biotech industry.

Characteristics of Heat-Resistant Gloves

The characteristics of heat-resistant gloves vary according to their material composition:

1. Cotton Material

Cotton gloves, used extensively in military applications, are highly absorbent and offer broad utility thanks to their heat resistance. Blends of cotton with polyester or rayon add features like wrinkle resistance and faster drying.

2. Silicone Material

Silicone gloves withstand temperatures above 200°C and are water-repellent, making them ideal for food industry and cleanroom applications due to their resistance to dust and contaminants.

3. Aramid Fiber

Aramid fibers, resistant up to 370°C, are noted for their flame resistance but are susceptible to degradation from UV exposure, acids, and alkalis.

4. Polyurethane Material

Polyurethane offers good elasticity and heat resistance up to 150°C, along with notable cold resistance, making it versatile for various applications.

5. Silica Fiber (Inorganic Fiber)

Silica fibers withstand temperatures between 600°C to 800°C, surpassing the capabilities of organic fibers for high-temperature applications.

Other Information on Heat-Resistant Gloves

1. Inspection of Heat-Resistant Gloves

Regular inspection is vital to ensure the effectiveness of heat-resistant gloves. Continuous use can lead to deterioration, potentially compromising their protective capabilities. Specifically, aramid fibers, which are susceptible to UV, acids, and alkalis, require careful inspection to maintain their integrity.

Proper management and pre-use checks are critical to avoid impairing the gloves’ fire retardant properties through wear, contamination, or improper maintenance.

2. Accident Cases Related to Burns

Despite the widespread use of heat-resistant gloves for safety, accidents can occur due to several factors:

1. Failure to recognize hazards
2. Undefined work procedures
3. Lack of education on glove hazards and harmfulness

To mitigate risks, wearing the correct protective equipment and engaging in daily safety practices are essential. Awareness of potential dangers among workers and managers is key to preventing accidents.

What Is a Dosimeter?

A dosimeter is a measuring instrument used to measure the amount of radiation.

Instruments used for measuring radiation are commonly referred to as dosimeters, radiation measuring instruments, survey meters, and more. Dosimeters encompass a wide range of measuring instruments, including those with and without mechanical structures.

Some dosimeters, such as glass dosimeters, thermoluminescence dosimeters, and photoluminescence dosimeters, utilize radiation-induced changes in materials. These dosimeters do not require a power source when measuring radiation. Due to their lightweight nature, they can be worn by individuals for routine monitoring of radiation exposure. Such wearable dosimeters are commonly referred to as personal dosimeters.

In contrast, semiconductor dosimeters, which require a power supply, are also used as personal dosimeters. This is because they can be manufactured to be as small as electronic thermometers.

The term “radiation measuring instrument” is often used interchangeably with “dosimeter.” However, a survey meter is a specialized instrument primarily used for measuring (surveying) radiation levels in specific areas or surfaces to assess radiation contamination.

Uses of Dosimeters

Dosimeters are employed to measure long-term radiation exposure in various aspects of daily life and in occupational settings involving potential radiation exposure.

Strict radiation control measures are mandated by law in medical facilities, research facilities, industrial sectors, and other settings where radiation is utilized. Medical facilities may encounter radiation during X-ray and CT imaging procedures, while nuclear facilities may have radiation exposure risks associated with nuclear reactor operation, nuclear fuel handling, and radioactive material management.

Given the potential health hazards of radiation exposure, workers in radiation-prone environments are required to wear personal dosimeters during tasks involving radiation.

Principles of Dosimeters

Dosimeters are measuring instruments designed to measure the “dose” of radiation.

This “dose” encompasses various indicators, including:

• Absorbed dose (measured in Gy gray), representing the energy absorbed by a material from radiation
• Effective dose (measured in Sv sievert), which expresses the overall effect of radiation on an individual’s entire body
• Irradiation dose (unit: R- Roentgen), indicating the total radiation exposure
• Effective dose equivalent (measured in Sv sievert), a practical indicator for routine radiation monitoring, among others

Dosimeters directly measure the “number” of radiation “rays.” To assess the various types of doses mentioned above, dosimeters are designed to differentiate and detect different types of radiation. By measuring the number of radiation “rays” for each type and considering their respective effects on the human body, it becomes possible to evaluate the overall impact of radiation exposure.

Personal dosimeters typically display the effective dose equivalent (unit: Sv sievert). While assessing the effective dose is ideal for evaluating radiation’s impact on the human body, it is often challenging to measure this dose in real-time. Therefore, the effective dose equivalent, a practical measure, is commonly used for actual radiation monitoring.

However, because a significant amount of radiation exposure in a short time can pose health risks, some dosimeters can also measure the dose equivalent rate (measured in Sv/h), representing the effective dose equivalent per hour. In workplaces where radiation is used, the effective dose for workers is calculated based on the measured effective dose equivalent.

Types of Dosimeters

Various types of radiation exist, including neutron, alpha, beta, gamma, and X-rays, each with distinct characteristics and varying effects on the human body. Glass, thermoluminescence, and photostimulable luminescence dosimeters are capable of detecting β-rays, γ-rays, and X-rays.

1. Glass Dosimeters

Glass dosimeters rely on the phenomenon where irradiated glass emits fluorescence when exposed to ultraviolet light.

2. Thermoluminescence Dosimeters

Thermoluminescence dosimeters leverage the thermoluminescence phenomenon of solids. This phenomenon involves the emission of light by a substance, such as a phosphor, when heated after being irradiated by an external radiation source.

3. Photostimulated Luminescence Dosimeters

Photostimulated luminescence dosimeters operate based on the photostimulated luminescence phenomenon, wherein electrons in a metastable state absorb light energy and return to their ground state after exposure to radiation.

4. Semiconductor Dosimeters

Semiconductor dosimeters function on the principle that when a material is ionized by radiation, an electric current flows through a semiconductor.

How to Select a Dosimeter

The primary consideration when selecting a dosimeter is choosing one suitable for the type of radiation to be measured. Dosimeters designed for β- and γ-rays may differ from those intended for X-rays, and product specifications for X-rays can vary based on energy levels.

1. Glass Dosimeters, Thermoluminescence Dosimeters, and Photostimulated Luminescence Dosimeters

The aforementioned three types are ideal for long-term radiation monitoring. They do not provide immediate radiation dose readings on the spot but require processing and measurement of accumulated radiation doses. This approach is known as passive radiation monitoring. In contemporary practice, specialized companies typically handle this measurement.

Although these dosimeters do not offer immediate radiation dose readings, they are highly sensitive and well-suited for radiation monitoring based on cumulative exposure over several months. Additionally, vendors can provide records of radiation doses, enhancing convenience.

2. Semiconductor Dosimeters

Semiconductor dosimeters are suitable for situations where substantial radiation exposure is anticipated within a short timeframe, and immediate radiation dose readings are required. These dosimeters provide real-time measurements and are referred to as active dosimeters. Some models display the dose equivalent, which is the dose per hour, and emit warnings when the dose equivalent exceeds predefined levels. Consider whether these functions are necessary when selecting a dosimeter.

However, certain semiconductor dosimeters have limited data storage capacity in the main unit. In such cases, consideration should be given to how dose data will be recorded. Many organizations opt for a combination of active and passive dosimeters to monitor exposure doses during work and manage long-term radiation control effectively.

What Is a Dynamic Mechanical Analyzer (DMA)?

Dynamic mechanical analyzer (DMA) is an instrument that evaluates the viscoelasticity of a sample, which includes both viscosity and elasticity properties. DMA is used to understand the physical properties of materials, particularly polymers, and is essential in applications like plastic product development and food texture analysis.

There are two main types of viscoelasticity measurement instruments: DMA, which evaluates the dynamic mechanical analysis of individual materials such as metallic materials, and a rheometer, which assesses the viscoelasticity of paste-like materials similar to fluids.

Uses of Dynamic Mechanical Analyzer (DMA)

1. DMA

DMA is primarily used for evaluating plastic products and food textures, aiding in the understanding of properties such as shrinkage in the molding process of polymers and expansion during injection.

2. Rheometer

Rheometers are vital in characterizing the viscoelastic properties of materials in industries like food, pharmaceuticals, and cosmetics. They are used to quantitatively assess sensory characteristics such as texture and mouthfeel, ensuring consistent product quality.

Principle of Dynamic Mechanical Analyzer (DMA)

DMA measures viscoelasticity by applying an external force to a sample and observing the resulting behavior. The sample’s response to the applied force—whether it stores energy (elasticity) or dissipates heat (viscosity)—provides insights into its viscoelastic properties.

1. Viscosity

Viscoelasticity involves strain generation upon force application and the persistence of this strain even after the force is removed. This property is crucial in understanding the behavior of materials under stress and their subsequent recovery.

2. Elasticity

Elastic properties are observed when a material returns to its original state after the removal of an external force. This characteristic is important for materials that need to maintain their shape and structural integrity under varying conditions.

Types of Dynamic Mechanical Analyzer (DMA)

1. DMA

DMA is an instrument to measure dynamic mechanical properties. For example, viscosity and elasticity are important indicators in understanding the physical properties of polymeric materials. In the molding process of polymers, shrinkage of molded products and expansion during injection are issues.

This phenomenon is also caused by viscoelasticity which must be taken into account when designing molding. Mainly, equipment capable of measuring DMA is used. The external forces applied can be in tension, compression, cantilever bending, free-support 3-point bending, and shear modes.

2. Rheometer

Rheometers are used to measure viscosity properties in the food, pharmaceutical, and cosmetic industries. It is important to quantitatively evaluate the human sensory characteristics of food products, such as texture, chewiness, crispness, melt-in-the-mouth, and throat feel. Since there are individual differences in such sensory evaluation, numerical evaluation is indispensable to ensure stable quality.

Similar to a rheometer is a viscometer. Viscometers evaluate physical properties by applying an external force in only one direction, mainly rotation. The difference is that a rheometer, like a DMA, evaluates properties through vibration (sinusoidal waves).

Other Information on Dynamic Mechanical Analyzer (DMA)

Evaluation by Dynamic Viscoelasticity Measurement

Dynamic viscoelasticity measurements involve applying a cyclic oscillatory load to a sample and evaluating properties like storage modulus, loss modulus, and tan δ. These parameters provide a comprehensive understanding of a material’s elastic and viscous behaviors, indicating how it will perform under real-world conditions.

What Is a Bulk Solid Flowmeter?

A bulk solid flowmeter is a device designed to measure the flow rate of aggregates (such as powders or grains).

Although each particle of powder is a solid, it can behave like a fluid when moving in large aggregates. A bulk solid flowmeter utilizes this property of powders to capture and measure the flow rate of moving powder, similar to how fluid flow is measured.

Bulk solid flowmeters find application in various situations, depending on the type of powder and the measurement site.

Uses of Bulk Solid Flowmeters

Situations involving the measurement of large quantities of powder or particles are encountered in various industrial fields.

Bulk solid flowmeters are employed across a wide range of industries to measure and control raw materials and products. They are used in the food industry for items such as flour, milk powder, cocoa, sugar, and salt; in the agriculture and livestock industry for agricultural chemicals, fertilizers, feed, wheat, and rice; in the construction and engineering industry for materials like cement, slaked lime, incinerated ash, and sand; and in the chemical industry for pigments, lead oxide powder, and calcium carbonate. Bulk solid flowmeters are used to measure, control, and proportionally blend materials in various industries.

Depending on the substance being measured, there are situations where volume flow rate control is required, and others where mass flow rate control is necessary. There are flowmeters capable of handling both types of measurements.

Principles of Bulk Solid Flowmeters

There are several types of bulk solid flowmeters, each operating on a different principle.

1. Capacitance Type
   Powder is allowed to fall freely between electrodes consisting of two opposing metal plates, which act as capacitors. As the insulating powder passes between them, the capacitance increases in accordance with the relative permittivity of the powder and the flow rate. By continuously measuring the capacitance between the electrodes, the flow rate of the powder can be measured in real-time. This type of flowmeter can only measure free-fall bulk solid flow.
2. Microwave Type
   A bulk solid flowmeter that utilizes the Doppler effect. A sensor is installed in the conveying pipe, and it transmits microwaves while receiving the reflected microwaves. The frequency of the returned microwaves changes due to the Doppler effect caused by the powder particles passing through the pipe. The changed frequency is proportional to the number of particles, and the amplitude of that frequency is proportional to the average volume of the particles. Consequently, the powder flow rate can be calculated from the frequency and amplitude. This type can measure both free-fall and pneumatic powder flow rates.
3. Coriolis Type
   When powder is placed in a weighing wheel rotating by a motor, centrifugal force causes the powder to move outward with the wheel. During this movement, a Coriolis force is generated in the circumferential direction opposite to the direction of rotation. This Coriolis force is proportional to the mass of the powder, allowing the mass flow rate of the powder to be determined by measuring the Coriolis force. This type can only measure pneumatically conveyed powders.

Overview of Air Quality Monitors

Air quality monitors are devices designed to assess the air quality within an environment by measuring various parameters, including gases like carbon dioxide, carbon monoxide, and volatile organic compounds, as well as atmospheric conditions such as temperature, humidity, and particulate matter like PM2.5. These monitors are essential for ensuring air safety and comfort in various settings, from indoor spaces to industrial sites.

Applications

These monitors are utilized across multiple fields, including environmental monitoring, workplace safety, and in the maintenance of HVAC systems. They play a crucial role in identifying air quality issues, aiding in the prevention of pollution-related health problems.

Operating Principles

The functionality of air quality monitors is based on the detection of specific air quality indicators using advanced sensors. Technologies employed include infrared absorption for carbon dioxide, non-dispersive infrared (NDIR) for carbon monoxide, piezoresistive sensors for atmospheric pressure, and various humidity sensors for moisture levels. Temperature is typically measured with NTC thermistors, sensitive to minute changes in heat.

Types and Standards

Air quality monitors are categorized into two main types: those for outdoor use, assessed by the Air Quality Index (AQI), and those for indoor environments, evaluated through Indoor Air Quality (IAQ) standards. The AQI offers a standardized measure to gauge outdoor air pollution levels, while IAQ focuses on ensuring the health and comfort of indoor spaces.

What Is a Hardness Tester?

A hardness tester is an instrument used to determine the hardness of materials by measuring the size of deformation or marks left when a specific force is applied. Different hardness scales, such as Rockwell, Vickers, and Brinell, are used, and selecting a hardness tester that matches the test object’s characteristics is crucial.

While most hardness testers are stationary, there are also portable models for on-site testing.

Uses of Hardness Testers

Hardness testers play a vital role in product development and quality control, ensuring materials meet specific hardness requirements. They are used for quality verification, material comparison, research and development, and troubleshooting in product failure analysis.

Principles of Hardness Testers

Hardness testers use various measurement principles and should be chosen based on the material and its hardness. The types include Rockwell, Brinell, Vickers, Shore, durometer, pencil hardness, and Mohs Hardness methods, each with specific applications and measurement techniques.

1. Rockwell Hardness Tester

Uses a diamond indenter and measures hardness based on the depth of indentation. Variants like HRC, HRA, and HRB are used for different materials and applications.

2. Brinell Hardness Tester

Calculates hardness based on the indentation surface area created by a steel ball under load, suitable for objects with uneven hardness or rough surfaces.

3. Vickers Hardness Tester

Measures hardness from the diagonal length of the indentation made by a diamond square-weight indenter with a 136° facing angle and the load applied at the time of the indentation.

4. Shore Hardness Tester

Calculates dynamic resilience hardness by measuring the height of a diamond hammer’s bounce on the specimen.

5. Durometer

Used for softer materials like rubber and elastomer, measuring hardness based on the depth the indenter is pushed in.

6. Pencil Hardness Tester

Measures the surface hardness of coatings by applying a load to a pencil with a fixed tip shape and visually checking for scratches.

7. Mohs Hardness

Although not a hardness tester, there is a method for determining the hardness of minerals called Mohs Hardness, which uses standard minerals of known hardness levels for comparison.

Other Information on Hardness Testers

Notes on the Use of Hardness Testers

Hardness has no universal definition and varies based on the tester used. Regular inspections and calibrations are necessary to ensure accuracy. When comparing hardness values, using the same type of tester is recommended due to varying definitions of hardness across different devices.

What Is a Magnetizer?

A magnetizer is a device that generates a strong magnetic field to perform a process called “magnetization.” Magnetization is the process of imparting magnetic force to a magnetic material and is always necessary when creating permanent magnets. Permanent magnets, in general use, do not have magnetic force at the stage where the material is molded. They become permanent magnets when they are exposed to a strong magnetic field and magnetized. Various materials can be used as magnets, such as iron, nickel, and aluminum, but each has its own limit of magnetism. Magnetizers magnetize materials by applying a magnetic field up to the limit of their magnetism.

Uses of Magnetizers

Magnetizers are mainly used to create permanent magnets. Few natural magnet stones exist, and most industrially used magnets are magnetized using magnetizing equipment. Examples include iron, nickel, and cobalt. These materials can be strongly magnetized and are used where large magnetic forces are required. Other materials have different magnetic limits, so their use depends on the magnetic force they can provide. Industrially, magnetized materials are used in motors and various devices, such as speakers and sensors.

Principles of Magnetizers

To understand the principle of magnetizers, it is important to consider the “air-core coil,” “magnetizing yoke,” and “magnetizing” power source. These components are combined in the structure, and we will introduce the features of each of them.

• Air-Core Coil
  This is one of the components used for magnetization. It has the shape of a cylindrical coil without an iron core and generates a strong magnetic field at its center. A magnet can be created by placing a magnetic material inside this coil. It is a basic technology with a simple structure and has been used for a long time, but it can only create a simple magnet with one north (N) pole and one south (S) pole.
• Magnetizing Yoke
  The magnetizing yoke is another component that is magnetized similarly to an air-core coil. Unlike the air-core coil, the coil is wound around an iron core, which can be made in various shapes. Various types of magnets can be created by changing the shape of the iron core and coil according to the properties of the magnet to be made. Magnets with two or more poles and complex magnetization patterns are possible.
• Magnetizing Power Supply
  This is the power source required for a magnetizer. The air-core coil and magnetizing yoke are connected to this magnetizing power supply to generate a strong magnetic field. A very large current, often several thousand to several tens of thousands of amperes, is required for magnetization. The magnetizing power supply generates this high current, primarily using a capacitor.

What Is Vacuum Filling Machinery?

Vacuum filling machinery is a type of equipment used in the packaging process, utilizing a vacuum to fill products, particularly useful for items prone to oxidation. For example, in the food industry, vacuum filling can stabilize the quality of food products by removing oxygen, thus preventing oxidation. A common example is the vacuum-sealed jars of jam, which are often difficult to open due to the vacuum inside.

Uses of Vacuum Filling Machinery

This machinery is predominantly used in the food industry to prevent food deterioration due to oxidation. Vacuum filling is an alternative to nitrogen displacement filling, where nitrogen is used to expel oxygen. While both methods aim to prevent oxidation, vacuum filling is generally less expensive than using nitrogen.

Principles of Vacuum Filling Machinery

Vacuum filling works by first evacuating the gas from the container, creating a low-pressure environment. When a vacuum is formed inside the container and a valve on the liquid side is opened, the pressure difference between the piping and the container causes the liquid to be drawn into the container. However, this method carries the risk of forming pinholes, which can lead to leaks.

There are two primary methods to create a vacuum in these machines:

• Vacuum Pumps: These use the rotational force of a motor. Types include pumps with rotating blades at an eccentric position and roots-type pumps with a cocoon-shaped rotating body.
• Ejectors: Ejectors utilize the Venturi effect, where a constricted structure allows air to pass through at high speed, creating a partial vacuum in the area.

Overview of Vacuum Chambers

Vacuum chambers are sealed enclosures designed to remove air and other gases to achieve a low-pressure environment. They are crucial in various industries for processes requiring reduced atmospheric pressure to prevent oxidation, corrosion, and other air-induced reactions.

Applications

These chambers play a vital role in materials research, surface treatments like vapor deposition, and semiconductor manufacturing, enabling precise conditions for experiments and production processes.

Functionality

Vacuum chambers operate by using vacuum pumps to extract air, ensuring an airtight environment through robust sealing mechanisms. This process is essential for maintaining the desired vacuum level for specific applications.

Selection Criteria

Choosing the right vacuum chamber involves considering its intended use, required vacuum level, size, and construction material to ensure compatibility with the application’s demands and to achieve optimal results.

What Is Hazardous Material Pipe Inspection Equipment?

Hazardous material pipe inspection equipment is a non-destructive device used in production lines for detecting foreign substances in food and medicine manufacturing. This equipment is crucial for ensuring the safety of products consumed by humans, as foreign materials can cause health problems, and in severe cases, jeopardize the company’s reputation. It is a key control point in HACCP (Hazard Analysis Critical Control Point).

Traditionally, detection of organic substances like hair was done visually, but technological advancements have led to the development of machines for this purpose.

Uses of Hazardous Material Pipe Inspection Equipment

This equipment is used in various stages of production in food and pharmaceutical industries. For example, in a vegetable processing plant, post-processing inspection uses optical and deep-running technology to detect narrow objects. The process includes mixing, filling, and then passing the product through metal detectors and X-ray detectors, followed by sterilization and packaging. Various types of inspection equipment are used throughout a single product’s manufacturing process, tailored to the specific foreign matter risks of each product.

Principles of Hazardous Material Pipe Inspection Equipment

The operating principle varies depending on the type of equipment. Metal detectors work by detecting changes in electromagnetic waves caused by metal presence. X-ray detectors use X-rays to create images based on the varying transmission rates through the inspected object, similar to X-ray photography. This technology is particularly effective for detecting denser materials and can also function as a metal detector, although traditional metal detectors are more precise for thin or powdery metals.

Other developing technologies include devices using near-infrared rays to detect foreign matter based on the differential absorption wavelengths of moisture and food ingredients. These advancements enable the detection of foreign substances that match the color of the product or are in a state of decomposition, providing higher accuracy without relying on human visual inspection.