月: 2023年7月

What Is Wear Resistant Rubber?

Wear resistant rubber is a rubber material that is highly resistant to friction and abrasion.

It is used in environments and applications where abrasion due to friction and abrasion occurs. Its high resistance to abrasion allows it to be used for long periods of time. This reduces the frequency of replacement and maintenance, thus saving costs.

They also maintain their performance under intense friction and harsh environments, with little degradation. However, despite its durability, certain environmental conditions may cause deterioration and loss of effectiveness.

Proper material selection and appropriate protection are necessary when exposed to chemicals and extreme temperatures. Prolonged contact with oil can also degrade performance, so care should be taken.

Uses of Wear Resistant Rubber

Wear resistant rubber is used in a variety of applications. The following are typical applications:

1. Vehicles

Wear resistant rubber is widely used in the automotive industry. Tires, in particular, are a type of wear resistant rubber that can be used for long periods of time while withstanding friction with the road. It is also used in various mechanical parts such as engine mounts and brake pads.

Wear resistant rubber is also used in railroad vehicles and equipment. The high electrical insulating properties of rubber make it ideal for use as rail insulation and cushioning material. It protects rolling stock and rails from vibration and friction.

In addition, it is often used for roller coaster tires.

2. Mining and Construction Industries

In the mining and construction industries, wear resistant rubber is an important material. It is used in equipment such as conveyor belts and chute liners.

In the mining industry, it is often used to transport ore, and in construction, it is used to transport earth and sand. Because of its durability to withstand the transport of ores and construction materials, it is widely used in conveying equipment.

3. Industrial Machinery

Wear resistant rubber is often used in industrial machinery and machine parts. Wear resistant rubber is used for parts that continue to be used for long periods of time, such as gaskets, and for parts that frequently come in contact with hard substances (such as metal), such as robot hand jaws. It improves durability while controlling lubrication and friction.

Principle of Wear Resistant Rubber

Wear resistant rubber is a special rubber material that is generally highly resistant to friction and abrasion. Because of its elasticity, rubber can be deformed by external forces or friction and then return to its original shape. This elasticity provides resistance to abrasion.

However, substances called wear resistant agents are added to wear resistant rubber. Abrasion resistant agents are materials that impart effective physical properties against friction, carbon black being one example. Carbon black not only improves the strength and wear resistance of rubber but also helps reduce friction and wear.

Wear resistant rubber formulations are optimized to maximize wear resistance. The type of rubber material and wear resistant rubber, the amount added, and the ratio of wear resistant agents are often adjusted. Manufacturing processes are also optimized to maximize the properties of the rubber.

Various base materials are available, including those made of styrene-butadiene rubber and urethane rubber.

The basic physical properties and characteristics are the same as those of regular rubber, with wear resistant rubber having superior mechanical strength. In addition, as with other rubber products, processing and molding are easy.

How to Select Wear Resistant Rubber

When selecting wear resistant rubber, consider the application, wear resistance, stress, and other factors.

1. Intended Use

First, it is necessary to understand the requirements of the intended use clearly. It is important to select appropriate wear resistant rubber characteristics by considering factors such as the degree of wear, working environment, temperature, and pressure.

2. Frictional Wear Performance

The wear resistant performance of wear resistant rubber may vary. Since different types and grades of wear resistant rubber have different performance, it is necessary to select the appropriate rubber material to meet the wear resistance requirements.

3. Resistance to Stress

Resistance of rubber materials to stress must also be considered. The durability of wear resistant rubber is maximized within the appropriate stress and load ranges. By selecting a product with optimum stress, wear resistant rubber can be extended in service life.

What Is an Ampere-Hour Meter?

An ampere-hour meter is a device that measures the totalization of current over time. Also called a watt-hour meter, it is used to determine the amount of electricity used and the amount of electricity generated.

This machine, which is always installed in ordinary households, calculates monthly electricity rates by calculating the power consumed. Torque proportional to electric power is generated to rotate the disk, and the number of revolutions is calculated as the integrated current value.

In recent years, however, electronic ampere-hour meters that do not use a disk have been developed, and their measurement accuracy has improved.

Uses of Ampere-Hour Meters

Ampere-hour meters are used to measure electric power in various locations, the most familiar being household electric meters.

In addition to factories and large power plants, there is always at least one ampere-hour meter installed in each home. Its purpose is to calculate the electricity consumed in the home. Monthly power consumption is calculated by the ampere-hour meter, and the electric power company sets the electricity rate based on that value.

Analog ampere-hour meters, which are commonly used, are convenient because they measure only active power, but they are vulnerable to vibration and shock, so care must be taken when handling them.

Principle of Ampere-Hour Meters

Ampere-hour meters have been widely used as household power consumption meters. These were mainly mechanical, analog type machines, but in recent years digital, electronic types have also appeared.

• Mechanical Ampere-Hour Meter
  This is an ampere-hour meter that mechanically measures electric power from the number of revolutions of a disk. A torque proportional to the electric power is generated by the coil for voltage and the coil for current, which rotates the disk. The number of revolutions of this disk is measured as the integrated electric power. Although widely used for a long time, the disadvantage of this device is that it is difficult to miniaturize because of the use of a disk. It is also vulnerable to vibration and shock, so care must be taken when handling it.
• Electronic Ampere-Hour Meter
  This is an ampere-hour meter that measures current and voltage from an electric circuit built into a device and calculates electric power. Since it does not require a mechanical structure like a disk, it can be miniaturized and installed in a small space. It also has high measurement accuracy and can be used for a long period. It can also record hourly power consumption. This allows you to record information on power outages and to find out when you are using too much power. In addition to saving energy, the system can also check the amount of electricity generated by the hour for households with power generation equipment.

What Is a Hydrogen Sulfide Meter?

A hydrogen sulfide meter is a device that measures the concentration of hydrogen sulfide in air or water.

Hydrogen sulfide is a toxic gas and is sometimes monitored as an important parameter in various industrial fields and environmental studies. In particular, high concentrations of hydrogen sulfide have a high potential for health hazards.

Even low concentrations of hydrogen sulfide can cause eye and respiratory irritation and other symptoms. By using a hydrogen sulfide meter, the concentration of hydrogen sulfide in the work environment can be monitored to ensure the health and safety of workers.

It can also be released into the air or water, which can have a negative impact on the surrounding environment. It can be a causative agent of acid rain or have harmful effects on organisms in the water. A hydrogen sulfide meter can detect abnormal values at an early stage and prevent environmental pollution.

Uses of Hydrogen Sulfide Meters

Hydrogen sulfide meters are used in a variety of industrial fields and for environmental studies. The most common applications are for process control or working environment measurements.

1. Oil and Gas Industry

In the oil and gas industry, hydrogen sulfide meters are widely used for working environment measurements. Hydrogen sulfide is likely to be generated at work sites such as oil drilling and natural gas production plants. They are used to ensure the safety of the working environment and to monitor worker health risks.

2. Wastewater Treatment Plants and Sewage Facilities

Wastewater treatment plants and sewage facilities can produce hydrogen sulfide. Hydrogen sulfide meters are often used to monitor the concentration of hydrogen sulfide in wastewater and to provide indicators for proper treatment.

3. Public Places

Hydrogen sulfide meters may also be used to study hydrogen sulfide concentrations in public places and natural environments. Samples of lakes, air, etc. can be obtained to measure levels of hydrogen sulfide, which is useful for monitoring environmental pollution and for environmental protection activities.

Principle of Hydrogen Sulfide Meters

Hydrogen sulfide is detected using specific detection methods. Detection methods vary from chemical reactions to products that use physical changes.

It is possible to cover a defined hydrogen sulfide concentration range. Typical ranges are from a few ppb to several ppm, but may vary depending on the specific application.

Two measurement methods are common: continuous monitoring or intermittent sampling. In continuous monitoring, the instrument constantly measures hydrogen sulfide concentrations in air or water and provides real-time data. In intermittent sampling, samples are taken at specific time intervals and later analyzed.

Measurements are often displayed digitally or on an analog pointer. They may also have the ability to issue warnings or alarms when certain concentration levels are exceeded.

Types of Hydrogen Sulfide Meters

Several types of hydrogen sulfide meters exist. The following are examples of hydrogen sulfide meter types:

1. Portable Hydrogen Sulfide Meter

Portable hydrogen sulfide meters are available. Most are small and can be operated by batteries. They are suitable for on-site safety management and inspections because they allow workers to monitor concentrations while on the move.

Battery-powered products can often be recharged for use. Many products have real-time display of concentration and alarm functions.

2. Fixed Hydrogen Sulfide Meter

Fixed hydrogen sulfide meters are installed in a fixed location and continuously monitor hydrogen sulfide concentrations. They are typically used at a specific location, such as a factory, plant facility or pipeline. They are often used for safety management and process control.

The sensor and the main unit are connected by a cable, and the data is transmitted to a monitoring room or control system. Many products are capable of high-precision measurement and multifunctional monitoring, and are capable of issuing an alarm when outside the set value range.

3. Throw-in Hydrogen Sulfide Meter

This hydrogen sulfide meter is used by throwing in the sensor. They are used by holding a special handle or cable and throwing in the sensor or reagent. They are characterized by the fact that they can be used without coming close to a hydrogen sulfide atmosphere.

Other Information on Hydrogen Sulfide Meters

Health Hazards of Hydrogen Sulfide

10ppm is the limit concentration under irritation of the mucous membrane of the eye. 50ppm to 100ppm causes airway irritation and conjunctivitis. 100ppm to 200ppm causes olfactory paralysis, 300ppm causes subacute poisoning symptoms in one hour, 600ppm causes fatal poisoning in one hour, and 1,000ppm At 1,000 ppm, the concentration is said to be fatal immediately.

For this reason, most small portable hydrogen sulfide meters are limited to 50ppm.

What Is a Hot Air Drying Oven?

A hot air drying oven is a device used to dry hot objects. In processing hot materials, fuel is burnt within a burner and hot air is pumped into the oven to dry the hot object.

Because hot air drying ovens use hot air or gas, the drying rate is relatively fast and efficient. This makes it possible to shorten the drying time of products and materials.

However, the use of hot air or combustion gases may pose a fire hazard. Care must be taken not to allow flammable materials or combustible gases into the oven.

When gas or kerosene is used as a heat source, a large amount of exhaust gas is emitted. Therefore, electric hot air drying is also often used, which has a high heat rate and is easy to handle.

Uses of Hot Air Drying Ovens

Hot air drying ovens are widely used in various industries and fields. The following are some examples of applications.

1. Food Processing and Pharmaceuticals

Fruits, vegetables, and other agricultural products are dried to improve their shelf life, and raw materials used in food processing processes are dried. Production of fruit chips, dried vegetables, dried noodles, dried spices and herbs are examples of use.

In the pharmaceutical industry, drying of drugs and medicines is also an important process. Hot air drying ovens are used to dry, crystallize, and coagulate drugs. Drying improves the stability of drugs and allows for long-term storage and handling.

2. Industry

The chemical industry often needs to dry raw materials and products such as paints and plastics. They are used to remove water from these materials and dry them.

Also, in the mining industry, ores and minerals are often dried before being fed into a blast furnace. Feeding moisture into the blast furnace not only removes heat from the furnace but also increases exhaust gases. Hot air drying ovens can be used to evaporate the moisture content of ores and minerals in advance to improve handling and processing efficiency.

In ceramics manufacturing, drying is performed prior to forming and firing of ceramics. Hot air drying ovens are used to remove moisture from ceramic products to ensure uniform quality and durability.

3. Wood Processing

In the wood processing industry, wood drying is an important process. Hot air drying ovens are used to properly control the humidity of the wood and dry it to improve its stability. This prevents shrinkage and cracking of the wood and improves product quality.

Principle of Hot Air Drying Ovens

Hot air drying ovens use hot air or gas to evaporate moisture from moist materials. They also have heating devices, such as electric heating elements or burners. This heating device will burn fuel or use electrical energy to produce hot air.

Hot air drying ovens also have a blower that sends heated air or gas into the hot air drying oven. The hot air is blown at high speed and spreads around the material or product. The hot air comes in contact with the surface of the material, allowing moisture to evaporate.

Water vapor and exhaust gases generated during drying are discharged to the outside through an exhaust system. The exhaust system removes moisture and harmful gases inside the drying oven.

Types of Hot Air Drying Ovens

There are two types of hot air drying ovens: direct drying and indirect drying.

1. Direct Drying Type

In the direct drying method, heated combustion gas is directly circulated by a circulation fan. It has the advantage of high thermal efficiency and can raise the temperature in a short time.

2. Indirect Drying

In the indirect drying method, a heat exchanger is heated by a burner, and combustion gas and air are exchanged to raise the temperature inside the furnace and circulate it. This method is characterized by the fact that heat is spread throughout the entire furnace, resulting in less unevenness in drying. There is no risk of soot entering the furnace due to incomplete combustion.

In addition, sparks from direct combustion do not come into contact with flammable components, so the risk of explosion is low. Since nitrogen oxides are unlikely to react with the paint during drying, the advantage is that the physical properties of the paint film are not compromised. However, it has low thermal efficiency and takes a long time to raise the temperature.

What Is Non-Shrink Mortar?

Non-Shrinking Mortar is a material used as part of the wall or framework of a building and is a type of material called mortar.

Mortar is a material used when cement, sand, and water are mixed and allowed to harden. Generally, mortar has the property of shrinking when it hardens, but mortar that does not shrink when it hardens is called Non-Shrinking Mortar.

If water-containing mortar shrinks significantly as it sets, it can lead to cracking. Non-Shrinking Mortar prevents the mortar from cracking by suppressing shrinkage during setting.

Applications of Non-Shrinking Mortar

Non-Shrinking Mortar is used in three major applications

1. joint between steel column base and foundation

The base of a steel-framed building must be fixed to a foundation such as reinforced concrete. Non-Shrinking Mortar is injected into the joint to strengthen the bond between the steel frame and the foundation.

2. seismic reinforcement

Non-Shrinking Mortar is used for earthquake-resistant reinforcement of concrete buildings. Non-Shrinking Mortar is used at the anchor points that secure the concrete to the reinforcement, such as steel braces, as well as at the joints between the steel columns and the foundation. By strongly anchoring the reinforcement, it is possible to increase the seismic strength of the building.

3. Repair of concrete structures

Non-Shrinking Mortar is used to repair concrete structures by filling in cracks caused by deterioration. For example, it can be used for “ground improvement” of weakened ground due to excessive extraction of underground water sources, “reinforcement of cracks in concrete walls,” “prevention of bedrock delamination,” and “filling reinforcement” of aged RC structures.

Principle of Non-Shrinking Mortar

The principle of Non-Shrinking Mortar’s non-shrinking property is that it contains an expansion agent. Non-Shrinking Mortar contains a lime-based expander, etc., and has a slight expansive property.

By adding a material that expands to a mortar that shrinks, the material as a whole exhibits Non-Shrinking Mortar or slight expansion.

Types of Non-Shrinking Mortar

There are two types of Non-Shrinking Mortar: “grout” and “pad. Both are chosen according to the construction method.

1. grout type

Grout is a liquid material that is poured into a mold or other container and used to fill a certain space. Since grout has high fluidity, it is easy to fill gaps and is suitable for reinforcing structures.

2. pad type

Pads are used like ordinary mortar, spread out with a trowel. It is less fluid than grout and can be spread on vertical walls.

Other Information on Non-Shrinking Mortar

Non-Shrinking Mortar Method

Non-Shrinking Mortar is called “no-shrink” but it does not mean that it does not expand at all. Although the basic characteristics are watertight and no-shrinkage, a slight expansion may produce the maximum effect depending on the application. One construction method that takes advantage of Non-Shrinking Mortar’s expansive properties is the CFT method. In the hybrid high-rise CFT method, Non-Shrinking Mortar is used as the base material for filling steel pipes.

The principle of the CFT method is based on the mutual restraint (confinement effect) of the outward expansion force of the grouted mortar and the restraining force of the steel pipe. This method has been attracting attention in recent years because it is less expensive than the steel-filled method and, on top of that, has relatively high strength. However, the properties of Non-Shrinking Mortar are the same as those of concrete, and its strength is reduced by neutralization.

Concrete neutralization is a phenomenon in which concrete, which is inherently highly alkaline, approaches neutrality when carbon dioxide from the atmosphere enters the concrete. This phenomenon leads to corrosion of the reinforcing steel inside. In addition, since machine kneading is essential for construction, procurement of equipment is indispensable, and strength and durability are limited only to cases where the concrete is airtight.

What Is an Earth-Leakage Circuit Breaker?

An earth-leakage circuit breaker (ELCB) is an electrical safety device used to protect people from electrical leakage.

By connecting an earth-leakage circuit breaker plug to an electrical outlet, it is possible to prevent personal injury caused by electrical leakage from electrical equipment and appliances. In some household distribution boards, breakers without a leakage current function are used.

If leakage current occurs from electrical equipment or appliances, there is a risk of personal injury. Using an earth-leakage circuit breaker to connect to the equipment can prevent these accidents. In addition, electrical leakage can cause fires. An earth-leakage circuit breaker can also reduce the risk of fire because it detects leakage and shuts off the power supply.

However, when using an earth-leakage circuit breaker, it is important to verify proper specifications and standards. Incorrect selection may result in a risk of incorrect functioning.

Uses of Earth-Leakage Circuit Breakers

Earth-leakage circuit breakers are used in a variety of applications. In general, they are often used for household appliances.

1. General Household

Earth-leakage circuit breakers are used for electrical appliances and home electronics used in the home. Refrigerators, washing machines, and microwave ovens are typical examples. They reduce the risk of electric shock and fire due to electrical leakage and improve home safety.

2. Offices and Commercial Facilities

In offices and commercial facilities, earth-leakage circuit breakers are often connected to printers, telephones, and other office automation equipment. This prevents electrical shock accidents and ensures a safe working environment.

3. Construction Sites

Electric tools are frequently used on construction sites. These tools require high power and may cause electrical leakage. By using an earth-leakage circuit breaker, the power supply of the tools can be protected and the workers can be protected from electric shock.

Principle of Earth-Leakage Circuit Breakers

The principle of an earth-leakage circuit breaker is to detect a leakage and cut off the power supply. A leakage current detector is often incorporated to detect leakage current. The leakage current detector uses a sensor that detects differences in the current.

The RCD compares the current from the power supply to the equipment with the current from the equipment to the power supply. Normally, these two currents should flow the same amount, but when a leakage current occurs, a leakage current is generated. This difference is detected by the leakage current detector.

The leakage current is detected when the difference in current exceeds a certain set value. The set value is generally a few mA to a hundred mA. This set value is appropriately set based on the risk of electric shock or fire.

When an earth-leakage circuit breaker is detected, the shutdown mechanism in the earth-leakage circuit breaker is activated and the power supply is immediately disconnected. This will stop the power supply to the circuit or device where the leakage has occurred, reducing the risk of electric shock or fire.

How to Choose an Earth-Leakage Circuit Breaker

When selecting an earth-leakage circuit breaker, the following factors should be considered:

1. Protective Function

The main purpose of an earth-leakage circuit breaker is to detect leakage and shut off the power supply. However, earth-leakage circuit breakers with overcurrent protection are also available. The presence or absence of an overcurrent protection function should be considered when purchasing a plug.

2. Number of Poles

The number of poles in an earth-leakage circuit breaker refers to the number of pins in the plug. Generally, it is 2 or 3 poles. In order to select the proper number of poles, it must match the requirements of the electrical equipment or appliance being used and the number of poles in the outlet to which it is connected.

3. Voltage Rating

The voltage rating of an earth-leakage circuit breaker indicates the voltage range of the power supply suitable for normal operation. It should be matched to the appropriate voltage range for the electrical equipment and appliances used. For general household use, the voltage is 100V or 200V, with 100V being the most common.

4. Current Rating

The current rating of an earth-leakage circuit breaker plug is the maximum current that the plug can handle. It is important to select a plug with a current rating higher than the total current consumption of the electrical equipment used. Failure to select an appropriate current rating may result in burnout or other failures.

5. Current Sensitivity

The sensitivity current of an earth-leakage circuit breaker is the set value of sensitivity for detecting leakage current. Most common earth-leakage circuit breaker products have a sensitivity current of several mA to 20 mA. Since the ground fault current at the time of an accident varies depending on the situation, it is safer to use a product with a smaller sensitivity current.

Some earth-leakage circuit breakers may be classified into high-sensitivity, intermediate-degree, and low-sensitivity types.

What Is a Water Leak Detector?

A water leak detector is a device that can check for water leaks in pipes.

Many pipes, such as water pipes, are installed underground. These underground pipes cannot be visually inspected for leaks. It is not practical to dig out the pipes every time for inspection because it is too costly and requires too much work.

Water leak detectors can be used to inspect areas that cannot be directly touched, because they use the sound that is made when a leak occurs to detect leaks. Naturally, it can also be used to inspect piping that can be seen.

Usage of Water Leak Detectors

Water leak detectors can be used to detect leaks in pipes that cannot be seen directly, such as underground. Therefore, they are used to check for leaks in water pipes buried in the street or to locate leaks.

Apart from underground piping, the inspection of household water systems is the main example of its use. They are widely used to detect leaks in toilet pipes, hot-water pipes for baths, water receiving tanks, and water meters.

For visible piping, such as valves, visual inspection and water leak detector inspection are sometimes performed at the same time.

Principle of Water Leak Detectors

When a leak occurs, an unusual water noise is heard as the water flows. For this reason, the sound-based leak detection method is widely used to detect leaks. In the case of underground water pipes, there is a risk that a leak could lead to a major disaster, such as flooding of roads, so water leak detection is a socially necessary technology.

Water leak detection by sound has been used for a long time, but the conventional method is to use a listening stick. However, the conventional method of using a listening stick to detect water leakage has the problem that the operator must identify the sound of water leakage by himself, which is affected by the skill of the operator and individual differences. In addition, water leak detection is difficult if the target sound is buried by road noise and other noises other than the sound to be detected.

Water leak detectors are able to treat sound as an electrical signal, making these issues less likely to arise. For example, the problem of differences in judgment results among operators can be solved by setting a common reference value based on the detector’s meter. Other signal processing can be used to remove noise, or to make the sound of a leak easier to hear by emphasizing or reducing certain frequencies.